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Sample records for aisi 904l con

  1. Electrochemical Study of Welded AISI 304 and 904L Stainless Steel in Seawater in View of Corrosion

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    Richárd Székely

    2010-10-01

    Full Text Available This is a comparative study of the corrosion behaviour of welds in AISI 304 and AISI 904L stainless steels carried out in seawater model solution in the temperature range 5-35°C and the standard of corrosion testing of welds was followed. The corrosion rate and corrosion attack characteristics were determined for welds of the examined steels with several type of treatment. The aim of this work was to compare the steels based on their resistance against the corrosion in terms of pitting potential (Epit and repassivation potential (Erepass. Seawater is an electrochemically aggressive medium, which can initiate localised corrosion in welded stainless steels. Different electrochemical and testing methods were used, including cyclic voltammetry, chronopotentiometry, electrochemical impedance spectroscopy (EIS, pH measuring and penetration tests.

  2. Evaluation of the AISI 904L Alloy Weld Overlays Obtained by GMAW and Electro-Slag Welding Processes

    Science.gov (United States)

    Jorge, Jorge C. F.; Meira, O. G.; Madalena, F. C. A.; de Souza, L. F. G.; Araujo, L. S.; Mendes, M. C.

    2017-03-01

    The use of superaustenitic stainless steels (SASS) as an overlay replacement for nickel-based alloys can be an interesting alternative for the oil and gas industries, due to its lower cost, when compared to superalloys. Usually, the deposition is made with several welding passes by using conventional arc welding processes, such as gas tungsten arc welding (GTAW) or gas metal arc welding (GMAW) processes. In this respect, electro-slag welding (ESW), which promotes high heat inputs and low dilution of the welds, can also be attractive for this application, as it provides a higher productivity, once only one layer is needed for the deposition of the minimum thickness required. The present work evaluates the behavior of an AISI 904L SASS weld overlay deposited on a carbon steel ASTM A516 Grade 70 by ESW and GMAW processes. Both as-welded and heat-treated conditions were evaluated and compared. A multipass welding by GMAW process with three layers and 48 passes was performed on 12.5 × 200 × 250 mm steel plates with average welding energy of 1.0 kJ/mm. For ESW process, only one layer was deposited on 50 × 400 × 400 mm steel plates with average welding energy of 11.7 kJ/mm. After welding, a post-weld heat treatment (PWHT) at 620 °C for 10 h was performed in half of the steel plate, in order to allow the comparison between this condition and the as-welded one. For both processes, the austenitic microstructure of the weld deposits was characterized by optical microscopy and scanning electron microscopy with electron backscatter diffraction. A low proportion of secondary phases were observed in all conditions, and the PWHT did not promote significant changes on the hardness profile. Martensite for GMAW process and bainite for ESW process were the microstructural constituents observed at the coarse grain heat-affected zone, due to the different cooling rates. For ESW process, no evidences of partially diluted zones were found. As a consequence of the microstructural

  3. Comportamiento electroquímico de un acero inoxidable AISI 430 implantado con cerio

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    Abreu, C. M.

    2002-10-01

    Full Text Available Chemical treatment in solutions containing cerium compounds has been widely used for prevention of localized corrosion in aluminium alloys (pitting corrosion as well as in stainless steels (crevice corrosion. Ionic implantation presents several advantages for stainless steels. The present paper is devoted to study the effect of cerium implantation on the properties of passive films formed on an AISI 430 stainless steel in alkaline medium. The electrochemical study is performed by cyclic voltammetry and EIS. The chemical characterisation of the oxides film developed is performed by XPS, and the morphological study corresponds to SEM examination. The results show that cerium implantation hinders magnetite formation as well as chromium oxidation processes.

    En los últimos años, se ha extendido el uso de disoluciones de sales de cerio como tratamiento para mejorar la resistencia localizada de las aleaciones de aluminio y para incrementar la resistencia a la corrosión en resquicio de diversos aceros inoxidables. En el caso de estos últimos, la adición de cerio mediante implantación iónica supone notables ventajas con respecto a otros tratamientos. En este artículo se investiga el efecto que ejerce la implantación de cerio sobre la película pasivante de un acero inoxidable ferrítico AISI 430. Para ello, se analiza el comportamiento electroquímico en medio básico mediante la utilización de voltametría cíclica y espectroscopia de impedancia electroquímica. La caracterización química de la película de óxidos formada se realiza mediante XPS, y el estudio morfológico mediante SEM. Los resultados muestran una importante inhibición en la formación de magnetita, así como una reducción en el proceso de oxidación que experimenta el cromo en el acero implantado con cerio.

  4. Structure and properties of the Stainless steel AISI 316 nitrided with microwave plasma; Estructura y propiedades del acero inoxidable AISI 316 nitrurado con plasmas de microondas

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    Becerril R, F

    1999-07-01

    In this work were presented the results obtained by nitridation on stainless steel AISI 316 using a plasma generated through a microwave discharge with an external magnetic field using several moistures hydrogen / nitrogen to form a plasma. The purpose of nitridation was to increase the surface hardness of stainless steel through a phase formation knew as {gamma}N which has been reported that produces such effect without affect the corrosion resistance proper of this material. (Author)

  5. Comportamiento tribológico del acero AISI W112 con endurecimiento lineal mediante laser de ND:YAG.L. // Tribological behavior of AISI W112 steel with lineal hardening by means of ND:YAG laser.

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    R. Sagaró

    2001-07-01

    Full Text Available Para disminuir el desgaste en los sistemas tribológicos frecuentemente se acostumbra a endurecer localmente aquellaszonas sometidas a desgaste. En el presente trabajo, para incrementar la dureza y la resistencia al desgaste del acero AISIW112 se empleó un láser de Nd:YAG. Las características de fricción y desgaste del acero AISI W112 en condiciones decontacto deslizante en fricción seca con el acero 65MN4 fueron evaluadas para tratamientos convencionales luego de suirradiación con láser. En el trabajo se presentan además las transformaciones que ocurren durante el tratamiento con láser,así como la influencia de los parámetros operacionales del láser en la profundidad de la capa endurecida y lascaracterísticas tribológicas. El trabajo experimental corroboró que la resistencia al desgaste del acero AISI W112 es variasveces superior en comparación con los tratamientos convencionales.Palabras claves: Comportamiento tribológico, endurecimiento lineal, tratamiento superficial con láser._______________________________________________________________________________Abstract.Diminishing wear in tribological systems is usually done by locally hardening those areas subject to wear. In this paper ispresented the increasing of hardness and resistance to wear of AISI W112 steel by means of a Nd:YAG laser. Thecharacteristics of friction and wear of AISI W112 steel under sliding contact in dry friction conditions with the 65MN4steel were evaluated for conventional treatments and after laser irradiation. In the work are presented the transformationsthat take place during the laser treatment, as well as the influence of the laser operational parameters in the depth of thehardened layer and the tribological characteristics. The experimental work corroborated that the resistance to wear of AISIW112 steel is several times superior in comparison with conventional treatments.Key words: Tribological behavior , lineal hardening, laser superficial

  6. Precipitation of σ phase in superaustenitic stainless steel UHB 904L

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    F. Tehovnik

    2017-01-01

    Full Text Available Superaustenitic stainless steel UHB 904L with high Mo concentrations is widely used in applications that require high toughness and corrosion resistance. Given certain thermal histories, UHB 904L may be susceptible to the formation of potentially detrimental intermetallic phases, such as the σ (sigma phase. The formation of the σ phase is promoted by high concentrations of Cr and Mo, while elements such as carbon, nickel and nitrogen retard its formation. Samples of UHB 904L were isothermally annealed within the temperature range between 850 – 1 000 °C, for 8 h each, followed by water quenching. Microstructural analyses using light and electron microscopy showed that the σ phase forms at temperatures up to 1 000 °C. The tensile specimens were solution treated at 1 000 °C, 1 060 °C, 1 100 °C and 1 140 °C for 0,5 h, followed by water quenching. The tensile tests were performed at room temperature.

  7. Evolución de las características de dureza del acero AISI 304 con el tratamiento térmico

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    López, A.

    2001-04-01

    Full Text Available The evolution of the microstructure and hardness of commercial AISI 304 stainless-steel samples with the heat treatment has been studied. Steel specimens in the as-received condition, and after 50% cold rolling, were soaked for 1 hour at various temperatures between 650 and 1200 °C. Samples, maintain their grain size and hardness until about 900 °C; thereafter, size increases with temperature, while hardness lightly-diminishes. Recrystallization of cold-rolled specimens begins at 650 °C, and finishes around 850 °C. Recrystallized grain-size reaches the value found in the as received material after the treatment at 900 °C. For high her annealing temperatures both grain growth and hardness decrease following the same trent in cold-worked and non-deformed materials.

    Se ha estudiado la evolución que experimenta la microestructura y las propiedades mecánicas (dureza de un acero inoxidable austenítico AISI 304 de calidad comercial, cuando se somete a tratamientos térmicos tras una deformación en frío, por laminación, del 50%. En tratamientos isócronos, de una hora de duración, la recristalización del acero y su ablandamiento comienza a los 650 °C, completándose alrededor de los 825 °C. Entre 650 y 900 °C, se produce un crecimiento de grano recristalizado cuyo tamaño no alcanza el del grano original hasta los 925 °C, aproximadamente. A mayores temperaturas, hasta 1.200 °C, tiene lugar un manifiesto crecimiento del grano austenítico con un ligero descenso en los valores de dureza. El comportamiento del acero laminado y tratado se ha comparado con el de muestras calentadas, en las mismas condiciones, pero sin deformación previa en frío.

  8. High temperature cyclic oxidation of AISI 310 steel in atmospheres with variable oxidation content; Oxidacion ciclica de un acero refractario AISI 310 a alta temperatura en atmosferas con centenidos de oxigeno variables

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    Higuera-Hidalgo, V.; Belzunce-Varela, F. J.; Riba-Lopez, J.

    2005-07-01

    High temperature oxidation test of an AISI 310 stainless steel was performed in two different environments: in an standard atmosphere (21% oxygen) at 704, 800, 884 and 1,000 degree centigree and in the typical environment of a gas turbine and vapor generator of a combined-cycle electric generation unit (10%oxygen) at 800 and 1,000 degree centigree. The oxidation kinetics was determined by means of the measurements of the weight gain per unit surface of the specimen and also determining the thickness of the oxide layer. Comparable results have been obtained using both methodologies and the effect of the oxygen content along with the other experimental differences were determined observing the oxidation kinetics in both environments. The cyclic oxidation of AISI 310 deteriorates at temperatures higher than 1,000 degree centigree. (Author) 9 refs.

  9. DEFORMACIÓN ELÁSTICA RESIDUAL EN LÁMINAS DE ACERO AISI 304 RECUBIERTAS CON UNA PELÍCULA DE NITRURO DE TITANIO DEPOSITADA POR PVD-MAGNETRON SPUTTERING

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    H. A. COLORADO

    2009-01-01

    Full Text Available Se realizó una caracterización mediante difracción de rayos x (DRX en láminas de acero inoxidable AISI 304 recubierto con una capa de nitruro de titanio de 3 um de espesor, obtenida mediante deposición física de vapor (PVD-MAGNETRON SPUTTERING a una temperatura de 200 °C. se tomaron imágenes de microscopía electrónica de barrido (MEB, microscopía óptica (MO y microscopía de fuerza atómica (MFA para caracterizar el sustrato, la capa y la zona cercana a la intercara. adicionalmente se determinó la deformación elástica residual asociada con el ensanchamiento de los picos de DRX.

  10. Study of cyclic oxidation for stainless steels AISI 309 T 253 M A, with low additions of cerium; Estudio de la oxidacion ciclica de los aceros inoxidables AISI 309 T 253 MA, con pequenas adiciones de Cerio

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    Velazquez F, G.L.; Martinez, M.; Ruiz, A. [Universidad Nacional Experimental Politecnica (UNEXPO) - Vicerrectorado de Puerto Ordaz, Centro de Estudios de Corrosion. Puerto Ordaz. venezuela (Venezuela)

    1998-12-31

    It has been detected that the addition of small amounts (<1%) of the so called `reactive elements` such as Cerium to Fe-Cr alloys that was utilized in oxidating environment at high temperatures improving its resistance to oxidation under isothermal and cyclic conditions. In this work, it was evaluated the behavior under cyclic oxidation conditions for an austenitic stainless steel at chromium-nickel (253MA) with cerium addition, and comparing it with the AISI 310S austenitic stainless steel. The cyclic oxidation essays consist of five cycles by 24 hours each one, following of a cooling in air until ambient temperature from the temperatures of 850, 900 and 950 Centigrade, registering the gain mass of the specimen at end of each cycle. In order to this were prepared samples with dimensions of 20 mm. x 10 mm. x 1 mm. Later to the oxidation essays was evaluated the morphology of the corrosion products layer by scanning electron microscopy. The present phases were identified by X-ray diffraction and by chemical microanalysis by Dispersive energy (EDAX). The results obtained show that the steel with cerium addition, presents a higher adherence and resistance to the spalling noting that the cerium promotes the casting anchor of the oxides layer to matrix and by reducing the grain size of the layer improving its plasticity. Additionally the cerium promotes the preferential oxidation of the forming elements of protective layers like the chromium. (Author)

  11. Oxidación cíclica de un acero refractario AISI 310 a alta temperatura en atmósferas con contenidos de oxígeno variables

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    Higuera-Hidalgo, V.

    2005-06-01

    Full Text Available High temperature oxidation tests of an AISI 310 stainless steel was performed in two different environments: in an standard atmosphere (21 % oxygen at 704, 800, 884 and 1,000 °C and in the typical environment of a gas turbine and vapor generator of a combined-cycle electric generation unit (10 % oxygen at 800 and 1,000 °C. The oxidation kinetics was determined by means of the measurement of the weight gain per unit surface of the specimen and also determining the thickness of the oxide layer. Comparable results have been obtained using both methodologies and the effect of the oxygen content along with the other experimental differences were determined observing the oxidation kinetics in both environments. The cyclic oxidation of AISI 310 deteriorates at temperatures higher than 1,000 °C.

    Se ha llevado a cabo un estudio experimental sobre la oxidación a altas temperaturas de un acero inoxidable refractario AISI 310, en dos ambientes diferentes: en una atmósfera convencional (21 % de O2, a 704, 800, 884 y 1.000 °C y en un ambiente simulativo de una turbina de gas y del generador de vapor de uña central eléctrica de ciclo combinado (10-11 % de O2, a 800 y 1.000 °C. La cinética de la oxidación del material se ha determinado a partir, tanto de la ganancia de peso por unidad de superficie experimentada por las probetas objeto de ensayo como por la determinación de los espesores de las capas de óxido formados. Se han obtenido resultados comparables con ambas metodologías y se ha puesto de manifiesto el efecto del contenido de oxígeno y de las demás diferencias experimentales a partir de la comparación de las cinéticas de oxidación del acero en los dos medios oxidantes analizados. La oxidación del acero AISI 310 en situaciones térmicas cíclicas empieza ya a ser importante a partir de una temperatura de 1.000 °C.

  12. DEFORMACIÓN ELÁSTICA RESIDUAL EN LÁMINAS DE ACERO AISI 304 RECUBIERTAS CON UNA PELÍCULA DE NITRURO DE TITANIO DEPOSITADA POR PVD-MAGNETRON SPUTTERING

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    COLORADO, H. A.; SALVA, H. R.; GHILARDUCCI, A. A.

    2009-01-01

    se realizó una caracterización mediante difracción de rayos x (DRX) en láminas de acero inoxidable AISI 304 recubierto con una capa de nitruro de titanio de 3 mm de espesor, obtenida mediante deposición física de vapor (PVD-magnetron sputtering) a una temperatura de 200 ˚C. se tomaron imágenes de microscopía electrónica de barrido (MEB), microscopía óptica (MO) y microscopía de fuerza atómica (MFA) para caracterizar el sustrato, la capa y la zona cercana a la intercara. adicionalmente se dete...

  13. Modificación de los aceros rápidos de herramientas AISI M2 por fusión superficial con láser bajo diferentes condiciones de operación

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    Arias, J.

    2010-06-01

    Full Text Available We applied a laser surface melting treatment to AISIM2 high-speed steel –hardened and tempered- and studied the resulting surface characteristics (microstructure and mechanical behavior (hardness and wear performance. The steel was treated using a Nd:YAG continuous-wave laser with different operation conditions. The influence of the laser processing parameters on the single tracks and on melted surface layer obtained by multipass system with 50% overlap were studied. The microstructure for all conditions is formed byMC- and M2C-type carbides, martensite and retained austenite; the quantities of this phase depends on the operations conditions. It has been determined that low levels of power density and high speed scanning of the beam leads to greater homogeneity in the microstructure with high hardness values and wear resistance.

    Se ha aplicado el tratamiento superficial de fusión con láser a un acero comercial rápido de herramientas AISI M2, templado y revenido, y se ha estudiado su microestructura superficial y comportamiento mecánico (dureza y resistencia al desgaste. Para ello, se ha empleado un láser continuo Nd:YAG, variando las condiciones de operación, analizando la influencia de los distintos parámetros sobre cordones individuales y sobre las características de la superficie fundida cuando se realiza el tratamiento en multipasada con un solape del 50 %. La caracterización microestructural realizada de la superficie fundida muestra que, en todos los casos, se encuentra constituida por carburos de pequeño tamaño,M2C yMC, martensita y austenita retenida, cuya cantidad depende de los parámetros de operación. Así mismo, se ha determinado que valores bajos de densidad de potencia y altas velocidades de barrido del haz conducen a mayor homogeneidad en la microestructura, con altos valores de dureza y resistencia al desgaste.

  14. Surface fatigue and failure characteristics of hot-forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

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    Townsend, Dennis P.

    1987-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground AISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  15. Surface fatigue and failure characteristics of hot forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears

    Science.gov (United States)

    Townsend, D. P.

    1986-01-01

    Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground SISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

  16. Aluminum coating by fluidized bed chemical vapor deposition on austenitic stainless steels AISI 304 and AISI 316

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    Jose Luddey Marulanda-Arevalo

    2015-01-01

    Full Text Available Los revestimientos de aluminio f ueron depositados sobre aceros inoxidables AISI 304 y AISI 316 en el rango de temperatura de 5 60 a 600 °C por deposición química de vapor en lecho fluidizado(CVD – FBR. Se utilizó un lecho que consistía en 10 % de aluminio en polvo y 90 % de lecho inerte (alúmina, el cual fue fluidizado con Ar y como ga ses activadores se utilizó una mezcla de ácido clorhídrico con hidrógeno (HCl/H 2 . En el recubrimiento si n tratamiento térmico están las siguiente s especies: Al 13 Fe 4 , Fe 2 Al 5 , FeAl 2 y Al 5 FeNi, las cuales están presentes para ambos aceros. Además, el tratamiento térmico provoca la difusa de alu minio hacia el sustrato y la difusa de hierro del sustrato haci a la superficie del recubrimiento, haciendo la trans formación de los compuestos ant eriores a FeAl, Fe 2 Al 5 , FeAl 2 , Al 0.99 Fe 0.99 Ni 0.02 , AlNi y el Fe 2 AlCr. Se realizó la simulación termodinámica con el s oftware Thermo Calc para obt ener información de la posible composición y la cantidad de mat erial depositado, para condiciones seleccionadas. Las muestras recubi ertas y sin recubrir, se expus ieron a 750 ºC en una atmósfera d onde el vapor agua se transporta a las muestras usando un flujo de N 2 de 40 ml/min, más 100 % vapor de agua (H 2 O. Los dos sustratos sin revestir se comportaron de manera diferente, ya que el acero AISI 304 soportó bien el a taque y ganó poco peso (0.49 mg/cm 2 , en comparación con el acero AISI 316 que perdió mucho peso (25.4 mg/cm 2 . Los aceros recubiertos ganaron poco de peso durante las mil horas de exposición (0.26 mg/cm 2 y soportaron muy bien el ataque corrosivo en c omparación con sustratos sin r ecubrimiento.

  17. Comparing the Formability of AISI 304 and AISI 202 Stainless Steels

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    du Toit, M.; Steyn, H. G.

    2012-07-01

    The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced α' martensite. Although both grades are predicted to be susceptible to earing during deep drawing, AISI 202 displays a higher work-hardening exponent, higher average normal anisotropy, and a higher limiting drawing ratio than AISI 304. Similar cup heights were measured during Erichsen cupping tests, confirming that the two grades have very similar deep drawing properties. The results of this investigation therefore suggest that AISI 202 is a suitable alternative for AISI 304 in applications requiring good deep drawing properties.

  18. Comparative study of high temperature oxidation behaviour in AISI 304 and AISI 439 stainless steels

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    Antônio Claret Soares Sabioni

    2003-06-01

    Full Text Available This work deals with a comparison of high temperature oxidation behaviour in AISI 304 austenitic and AISI 439 ferritic stainless steels. The oxidation experiments were performed between 850 and 950 °C, in oxygen and Ar (100 vpm H2. In most cases, it was formed a Cr2O3 protective scale, whose growth kinetics follows a parabolic law. The exception was for the the AISI 304 steel, at 950 °C, in oxygen atmosphere, which forms an iron oxide external layer. The oxidation resistance of the AISI 439 does not depend on the atmosphere. The AISI 304 has the same oxidation resistance in both atmospheres, at 850 °C, but at higher temperatures, its oxidation rate strongly increases in oxygen atmosphere. Concerning the performance of these steels under oxidation, our results show that the AISI 439 steel has higher oxidation resistance in oxidizing atmosphere, above 850 °C, while, in low pO2 atmosphere, the AISI 304 steel has higher oxidation resistance than the AISI 439, in all the temperature range investigated.

  19. 904L不锈钢在氢氟酸和浓硫酸混合液中的腐蚀行为%Corrosion Behaviors of 904L Austenite Stainless Steel in Concentrated Sulfuric Acid Containing Hydrofluoric Acid

    Institute of Scientific and Technical Information of China (English)

    曾洪涛; 向嵩; 刘松林; 何勇刚

    2013-01-01

    采用动电位极化曲线、循环极化曲线和电化学阻抗谱(EIS)研究了904L不锈钢在氢氟酸和浓硫酸混合液中的腐蚀行为.结果表明:氢氟酸含量低于2%(质量分数)时,对904L不锈钢在浓硫酸中的腐蚀有抑制作用;氢氟酸含量高于2%时,对904L不锈钢在浓硫酸中的腐蚀有促进作用.随着氢氟酸含量的增加,904L不锈钢的腐蚀由电化学步骤控制转变为传质和电化学步骤混合控制.EIS随着氢氟酸含量的增加从1个时间常数变为2个时间常数,即表现为高频容抗弧和低频感抗弧.%Potentiodynamic polarization curves,cyclic polarization curves and electrochemical impedance spectroscopy (EIS) were used to investigate the corrosion behaviors of 904L stainless steel in concentrated sulfuric acid containing hydrofluoric acid.The result shows that the corrosion of 904L stainless steel in concentrated sulfuric acid is inhibited when the mass fraction of hydrofluoric acid is less than 2%; while the corrosion is promoted when the mass fraction of hydrofluoric acid is higher than 2%.With the increase of hydrofluoric acid concentration,the corrosion controlling step changes from electrochemical reaction to mixed mass transportation-electrochemical reaction.EIS and the plots present the change of time contant from one to two,i.e.capacitance loop in high frequency and inductance loop in low frequency.

  20. Comportamiento termomecánico de aceros AISI 304

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    El Wahabi, M.

    2001-04-01

    Full Text Available The hot deformation behaviour of three AISI 304 (H, L and HP austenitic stainless steel with different carbon contents has been studied. An analysis of the parameters describing their hot flow curves was carried out. No heavy effect of the carbon content was found on most of the latter parameters. However, the work hardening and dynamic recovery behaviour showed clear differences depending on the given alloy, especially at high temperatures and low strain rates where the high carbon steel displayed larger work hardening and dynamic recovery rates than the other steels. The high purity steel (interstitial free displayed the lower stress levels as its hardening rate was slower than in the other two steels.

    Se llevó a cabo un estudio del comportamiento termomecánico de tres aceros inoxidables austeníticos tipo AISI 304 (H, L y HP con diferentes contenido en carbono, mediante la determinación de los parámetros que describen las etapas de deformación en caliente. No se notó un fuerte efecto del carbono en dichos parámetros, excepto en los que describen los procesos de endurecimiento y de restauración dinámica que muestran una cierta dependencia con la composición química, especialmente a bajos valores del parámetro de Zener-Hollomon, donde el acero de alto carbono (304H endurece y restaura más rápido que el de bajo carbono (304L, alcanzándose valores de tensión de pico similares en ambos casos. El material de alta pureza (libre de intersticiales toma valores de tensión de pico más bajos que los otros aceros, endureciendo más lentamente y con una velocidad de restauración similar a la del 304H.

  1. An investigation on weldability of AISI 304 and AISI 1040 steels on friction welding; Untersuchung der Schweisseignung von AISI 304 und AISI 1040 mittels Reibschweissen

    Energy Technology Data Exchange (ETDEWEB)

    Celik, Sare; Ay, Irfan [Balikesir Univ., Cagis Campus (Turkey). Mechanical Eng. Dept.; Dinc, Dincer [General Directorate of Highways, Canakkale (Turkey); Yaman, Ramazan [Balikesir Univ., Cagis Campus (Turkey). Industrial Eng. Dept.

    2010-04-15

    In welding technology, joining processes of different materials, which have dissimilar crystal structures are difficult. Welding of different materials becomes very important to reduce costs. Furthermore, the friction welding method is processed in lower temperature than the melting temperature. Especially, this is a big advantage to overcome difficulties that occur in the heat affected zone during usage of conventional methods. In this study, the weldability of AISI 304 stainless steel and AISI 1040 carbon steel by friction welding is studied. During the welding process, temperature variations in the welding zones were measured with an infrared temperature measurement device. After welding of the samples, tensile and hardness experiments were carried out. For metallographic investigations, optical microscope and scanning electron microscope (SEM) pictures were taken. Energy dispersive spectroscopy (EDS) analysis was carried out for composition investigations on welding and heat affected zones. As a result, these two steels could be joined by friction welding for industrial usage.

  2. State on AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    A. Fattah-alhosseini

    2011-01-01

    Full Text Available The passivity and protective nature of the passive films are essentially related to ionic and electronic transport processes, which are controlled by the optical and electronic properties of passive films. In this study, the electrochemical behavior of passive films anodically formed on AISI 304 stainless steel in sulfuric acid solution has been examined using electrochemical impedance spectroscopy. AISI 304 in sulphuric acid solution is characterized by high interfacial impedance, thereby illustrating its high corrosion resistance. Results showed that the interfacial impedance and the polarization resistance (pol initially increase with applied potential, within the low potential passive. However, at a sufficiently high potential passive (>0.4 V, the interfacial impedance and the polarization resistance decrease with increasing potential. An electrical equivalent circuit based on the impedance analysis, which describes the behavior of the passive film on stainless steel more satisfactorily than the proposed models, is presented.

  3. TIG AISI-316 welds using an inert gas welding chamber and different filler metals: Changes in mechanical properties and microstructure

    Directory of Open Access Journals (Sweden)

    Sánchez, A.

    2010-12-01

    Full Text Available This report analyses the influence of the use of an inert gas welding chamber with a totally inert atmosphere on the microstructure and mechanical properties of austenitic AISI 316L stainless steel TIG welds, using AISI ER316L, AISI 308L and Inconel 625 as filler metals. When compared with the typical TIG process, the use of the inert gas chamber induced changes in the microstructure, mainly an increase in the presence of vermicular ferrite and ferrite stringers, what resulted in higher yield strengths and lower values of hardness. Its effect on other characteristics of the joins, such as tensile strength, depended on the filler metal. The best combination of mechanical characteristics was obtained when welding in the inert gas chamber using Inconel 625 as filler metal.

    En este estudio se analiza la influencia que el uso de una cámara de soldadura de gas inerte tiene sobre la microestructura y las propiedades mecánicas de las soldaduras TIG en el acero inoxidable austenítico AISI-316L cuando se emplean AISI ER316L, AISI 308L e Inconel 625 como materiales de aporte. Cuando se compara con el típico proceso de TIG, el uso de una cámara de gas inerte induce cambios en la microestructura, incrementando la presencia de ferrita vermicular y de laminillas de ferrita, resultando en un aumento del límite elástico y una pérdida de dureza. Su influencia sobre otras características de las soldaduras como la carga de rotura depende de la composición del material de aporte. La mejor combinación de propiedades mecánicas se obtuvo usando el Inconel 625 como material de aporte y soldando en la cámara de gas inerte.

  4. Characterization of AISI 4140 borided steels

    Energy Technology Data Exchange (ETDEWEB)

    Campos-Silva, I., E-mail: icampos@ipn.mx [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Ortiz-Dominguez, M.; Lopez-Perrusquia, N.; Meneses-Amador, A. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico); Escobar-Galindo, R. [Instituto de Ciencia de Materiales de Madrid (CSIC), E-28049 Cantoblanco, Madrid (Spain); Martinez-Trinidad, J. [Instituto Politecnico Nacional, Grupo Ingenieria de Superficies, SEPI-ESIME U.P. Adolfo Lopez Mateos, Zacatenco, Mexico D.F., 07738 (Mexico)

    2010-02-01

    The present study characterizes the surface of AISI 4140 steels exposed to the paste-boriding process. The formation of Fe{sub 2}B hard coatings was obtained in the temperature range 1123-1273 K with different exposure times, using a 4 mm thick layer of boron carbide paste over the material surface. First, the growth kinetics of boride layers at the surface of AISI 4140 steels was evaluated. Second, the presence and distribution of alloying elements on the Fe{sub 2}B phase was measured using the Glow Discharge Optical Emission Spectrometry (GDOES) technique. Further, thermal residual stresses produced on the borided phase were evaluated by X-ray diffraction (XRD) analysis. The fracture toughness of the iron boride layer of the AISI 4140 borided steels was estimated using a Vickers microindentation induced-fracture testing at a constant distance of 25 {mu}m from the surface. The force criterion of fracture toughness was determined from the extent of brittle cracks, both parallel and perpendicular to the surface, originating at the tips of an indenter impression. The fracture toughness values obtained by the Palmqvist crack model are expressed in the form K{sub C}({pi}/2) > K{sub C} > K{sub C}(0) for the different applied loads and experimental parameters of the boriding process.

  5. Análisis experimental del torneado de alta velocidad del acero AISI 1045 // Experimental analysis of high speed turning of AISI 1045 steel gears

    Directory of Open Access Journals (Sweden)

    Luís Wilfredo Hernández‐González

    2012-01-01

    Full Text Available El objetivo de este trabajo es el estudio experimental de la evolución del desgaste del flanco de dosinsertos de carburo recubiertos y un cermet, durante el torneado en seco del acero AISI 1045 con 500 y600 m/min de velocidad de corte. Los resultados fueron comparados utilizando el análisis de varianza y deregresión. La investigación mostró un efecto significativo de la velocidad de corte y del tiempo demaquinado en el desgaste del flanco. El mejor desempeño fue para el carburo recubierto con tres capas,mientras que a elevada velocidad de corte el carburo con dos capas sufrió el mayor desgaste, lo cual sedebe a que cuando pierde sus recubrimientos el substrato del inserto queda desprotegido y el desgastecrece rápidamente por la extremas condiciones del mecanizado por alta velocidad. Además, se planteanrecomendaciones del tiempo de maquinado de los insertos dadas las condiciones de elaboración por altavelocidad.Palabras claves: torneado de alta velocidad, desgaste del flanco, acero AISI 1045, estudio experimental.__________________________________________________________________________AbstractThis work deals with the experimental study of the flank wear evolution of two coating carbide inserts and acermet insert during the dry turning of AISI 1045 steel with 500 and 600 m/min cutting speed. The resultswere compared using the variance and regression analysis. The investigation showed a significant effectof cutting speed and machining time on the flank wear in high speed machining. The three coating layersinsert showed the best performance while the two layers insert had the worst behaviour of the cutting toolwear at high cutting speed, this is because once the coating film is peeled off, the substrate of the insertbecomes uncovered and the wear grows rapidly due to the extreme machining conditions for high speed.Besides, the machining time recommendations of inserts for the cutting conditions at high speed areexposed.Key words: high

  6. Hot hardness characteristics of ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C, and Super Nitralloy

    Science.gov (United States)

    Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

    1973-01-01

    Short-term hot hardness studies were performed with ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C (14-4-1) and case hardened Super Nitralloy. Hardness levels of each material were measured at elevated temperatures in an electric furnace with a low oxygen environment. Test temperatures ranged from 294 to 877 K. The hot hardness characteristics of the ausformed AISI-M-50, Matrix 2 WD-65, and modified AISI 440-C were the same as those determined for high-speed tool steels. Hot hardness for these steels can be predicted within one point Rockwell C. The hot hardness characteristics of both the case and core of Super Nitralloy were superior to AISI 52100 but inferior to the high-speed tool steels. The short-term Rockwell C hardness at temperature for the Super Nitralloy material between 294 and 769 K can be predicted within one point Rockwell C hardness.

  7. "CARACTERIZACIÓN Y PROPIEDADES MECANICAS DE LA SOLDADURA DE UN ACERO INOXIDABLE FERRIRICO AISI 430"

    OpenAIRE

    Moreno Rodríguez, Arturo

    2012-01-01

    En la presente trabajo se investiga la soldabilidad del acero inoxidable ferrítico AISI 430. Las propiedades mecánicas y la microestructura se relacionan con las variables operativas del proceso de soldadura, de ahí que jueguen un papel importante para lograr óptimas propiedades. Buscando la mejora de las propiedades mecánicas de las uniones soldadas, posteriormente, se les aplicó un tratamiento térmico post-soldadura. Las uniones se realizaron mediante el proceso de soldadu...

  8. Resistencia al desgaste de recubrimientos Fe-Nb-Cr-W, Nb, AISI 1020 y AISI 420 producidos por proyección térmica por arco eléctrico

    Directory of Open Access Journals (Sweden)

    López-Covaleda, E. A.

    2013-10-01

    Full Text Available The commercial materials 140MXC (with iron, tungsten, chrome, niobium, 530AS (AISI 1015 steel and 560AS (AISI 420 steel on AISI 4340 steel were deposited using thermal spray with arc. The aim of work was to evaluate the best strategy abrasive wear resistance of the system coating-substrate using the following combinations: (1 homogeneous coatings and (2 coatings depositing simultaneously 140MXC + 530AS and 140MXC + 560AS. The coatings microstructure was characterized using Optical microscopy, Scanning electron microscopy and Laser confocal microscopy. The wear resistance was evaluated through dry sand rubber wheel test (DSRW. We found that the wear resistance depends on the quantity of defects and the mechanical properties like hardness. For example, the softer coatings have the biggest wear rates and the failure mode was characterized by plastic deformation caused by particles indentation, and the other hand the failure mode at the harder materials was grooving. The details and wear mechanism of the coatings produced are described in this investigation.Mediante proyección térmica de arco eléctrico fueron depositados tres materiales comercialmente conocidos como: 140MXC (a base de hierro, wolframio, cromo y niobio, 530AS (acero AISI 1020 y 560AS (acero AISI 420, sobre acero AISI 4340. Con el objetivo de evaluar la mejor estrategia para incrementar la resistencia al desgaste abrasivo, los recubrimientos fueron depositados de dos formas: (1 monocapas homogéneas de cada material y (2 recubrimientos depositando con alambres disimiles de 140MXC + 530AS y 140MXC + 560AS. Los recubrimientos fueron caracterizados microestructuralmente mediante Difracción de rayos X, Microscopía óptica, Microscopía láser confocal y Microscopía electrónica de barrido. La evaluación de la resistencia al desgaste abrasivo se realizó mediante ensayo con arena seca y rueda de caucho (DSRW. Se encontró que la resistencia al desgaste depende entre otras de las

  9. Mechanical and Microstructural Properties of Friction Welded AISI 304 Stainless Steel to AISI 1060 Steel AISI 1060

    Directory of Open Access Journals (Sweden)

    Ates H.

    2014-10-01

    Full Text Available Rotary Friction welding is one of the most popular methods of joining similar and dissimilar materials. It is widely used with metals and thermoplastics in a wide variety of aviation, transport and aerospace industrial component designs. This study investigates the influence of friction and upsetting pressures on the hardness, tensile properties and microstructure of the welds. The experimental results showed that as the friction and upsetting pressures increased, the hardness and tensile strength values increased, as well. The tensile fracture of welded joint occurred in the AISI 1060 side. The friction processed joints were evaluated for their integrity and quality aspects by optical and scanning electron microscopy. For the perfect interfacial bonding, sufficient upsetting and friction pressures are necessary to reach the optimal temperature and severe plastic deformation to bring these materials within the attraction range.

  10. Metallurgical and Mechanical Research on Dissimilar Electron Beam Welding of AISI 316L and AISI 4340

    Directory of Open Access Journals (Sweden)

    A. R. Sufizadeh

    2016-01-01

    Full Text Available Dissimilar electron beam welding of 316L austenitic stainless steel and AISI 4340 low alloy high strength steel has been studied. Studies are focused on effect of beam current on weld geometry, optical and scanning electron microscopy, X-ray diffraction of the weld microstructures, and heat affected zone. The results showed that the increase of beam current led to increasing depths and widths of the welds. The optimum beam current was 2.8 mA which shows full penetration with minimum width. The cooling rates were calculated for optimum sample by measuring secondary dendrite arm space and the results show that high cooling rates lead to austenitic microstructure. Moreover, the metallography result shows the columnar and equiaxed austenitic microstructures in weld zone. A comparison of HAZ widths depicts the wider HAZ in the 316L side. The tensile tests results showed that the optimum sample fractured from base metal in AISI 316L side with the UTS values is much greater than the other samples. Moreover, the fractography study presents the weld cross sections with dimples resembling ductile fracture. The hardness results showed that the increase of the beam current led to the formation of a wide softening zone as HAZ in AISI 4340 side.

  11. The influence of cutting speed and feed rate in surface integrity of aisi 1045//Influencia de la velocidad de corte y la velocidad de avance en la integridad superficial del acero aisi 1045

    OpenAIRE

    Mario Jacas-Cabrera; Tania Rodríguez - Moliner; José Luís Lopes-Da Silveira

    2015-01-01

    El objetivo de esta investigación es el estudio de la influencia de la velocidad de corte y la velocidad de avance en la integridad superficial del acero AISI-1045, sometido a un proceso de torneado. Las probetas se sometieron a un tratamiento térmico de recocidos (81 HRB). En el trabajo se empleó un diseño experimental 32, con dos variables a tres niveles experimentales, para un total de nueve experimentos, los que fueron replicados. La integridad superficial fue evaluada con la medición de ...

  12. Deformation induced martensite in AISI 316 stainless steel

    Directory of Open Access Journals (Sweden)

    Solomon, N.

    2010-04-01

    Full Text Available The forming process leads to a considerable differentiation of the strain field within the billet, and finally causes the non-uniform distribution of the total strain, microstrusture and properties of the material over the product cross-section. This paper focus on the influence of stress states on the deformation-induced a’ martensitic transformation in AISI Type 316 austenitic stainless steel. The formation of deformation-induced martensite is related to the austenite (g instability at temperatures close or below room temperature. The structural transformation susceptibility is correlated to the stacking fault energy (SFE, which is a function not only of the chemical composition, but also of the testing temperature. Austenitic stainless steels possess high plasticity and can be easily cold formed. However, during cold processing the hardening phenomena always occurs. Nevertheless, the deformation-induced martensite transformation may enhance the rate of work-hardening and it may or may not be in favour of further material processing. Due to their high corrosion resistance and versatile mechanical properties the austenitic stainless steels are used in pressing of heat exchanger plates. However, this corrosion resistance is influenced by the amount of martensite formed during processing. In order to establish the links between total plastic strain, and martensitic transformation, the experimental tests were followed by numerical simulation.

    El proceso de conformación da a lugar a una considerable diferenciación del campo de tensiones dentro de una barra de extrusión y, finalmente, causa una distribución no uniforme de la tensión total, la microestructura y propiedades del material sobre el corte transversal. En este trabajo se estudia la influencia de los estados de tensión sobre la transformación martensítica inducida por deformación en un acero inoxidable austenítico tipo AISI 316. La formación de martensita inducida por

  13. Evaluación del comportamiento a fatiga de una unión soldada a tope de acero AISI 1015//Evaluation of the fatigue behaviour of a butt welded joint of AISI 1015 steel

    Directory of Open Access Journals (Sweden)

    Pavel Michel Almaguer‐Zaldivar

    2015-01-01

    Full Text Available Las uniones soldadas son un componente importante de una estructura, por lo que siempre es necesario conocer la respuesta de las mismas sometidas a cargas cíclicas. El objetivo de este trabajo es obtener la curva S-N de una unión soldada a tope de acero AISI 1015 y electrodo E6013 como material de aporte. Los ensayos a fatiga se realizaron de acuerdo a la norma ASTM en una máquina universal MTS810. Se utilizaron probetas de sección rectangular. El ciclo de carga fueasimétrico a tracción, con un coeficiente de asimetría de 0,1. Se obtuvo que la unión estudiada tiene un límite de resistencia a la fatiga de 178 MPa, a un punto de corte de 2 039 093 ciclos.Palabras claves: unión soldada, fatiga, curva S-N, AISI 1015, electrodo E6013._______________________________________________________________________________AbstractWelded joints are an important component in structures, by this reason is necessary to know the behaviour of these elements under cyclic loads. The objective of this work is to obtain the S-N curve of the butt welded joint of AISI 1015 steel and electrode E6013 as the contribution material. Fatiguetest was realized within the ASTM standard in the MTS810 testing machine. Rectangular cross section specimens was used. Cyclic loads was asymmetric tensile and the asymmetry ratio used was 0,1. In this study was obtained the fatigue limit equal to 178 MPa, at the cut point of 2 039 093 cycles.Key words: welded joint, fatigue, S-N curve, AISI 1015 steel, electrode E6013.

  14. Comportamiento del desgaste del flanco en el torneado en seco de alta velocidad del acero AISI 316L//Flank wear behavior in the dry high‐speed turning of AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Yoandrys Morales-Tamayo

    2013-09-01

    Full Text Available El presente estudio experimental se centra en investigar los efectos de los parámetros corte en el desgaste de flanco con dos insertos recubiertos durante el torneado de acabado en seco a altas velocidades del acero inoxidable AISI 316L. Los efectos de los parámetros de corte fueron determinados utilizando un análisis de varianza y de regresión simple. Como principal resultado se obtuvo el efectosignificativo del avance y del tiempo de maquinado en el desgaste del flanco. El inserto de tres capas no sobrepasó el criterio de fin de vida del desgaste, mientras que el inserto de una capa sufrió un desgaste catastrófico para la mayor velocidad de corte. El desgaste del flanco tuvo mejor comportamiento para el avance de 0,08 mm/rev en todas las velocidades empleadas en este estudio.Palabras claves: torneado de alta velocidad, desgaste de flanco, acero inoxidable AISI 316L, estudio experimental, análisis de varianza y regresión.______________________________________________________________________________AbstractThe current experimental study is focused on investigating the effects of cutting parameters on flank wear in two coated carbide inserts during dry high speed finish turning of AISI 316L stainless steel. The effects of cutting parameters were determinate using analysis of variance and simple regression. As a main resulta significant effect of cutting feed and the machining time on flank wear was found. The three coating layers insert did not exceed the criterion of end of life of wear while the insert with one layer suffered a catastrophic wear at the highest cutting speed. The flank wear showed the best performance for the cuttingfeed of 0,08 mm/rev at all the speeds used in the study.Key words: high speed turning; flank wear; AISI 316L stainless steel, experimental study; analysis of variance and regression.

  15. Determinación de tensiones por rayos x del acero AISI 1045 deformado por rodillo // Determination of stress for x‐ray of the steel AISI 1045 deformed for roller

    Directory of Open Access Journals (Sweden)

    Tomás Fernández‐Columbié

    2012-01-01

    Full Text Available El objetivo del trabajo es realizar el análisis de las tensiones a muestras de acero AISI 1045 endurecidasen frío por rodillo. Con empleo del método de Willianson–Hall se determinó las macro ymicrodeformaciones; la deformación reticular del parámetro de red; el tamaño de las cristalitas; losesfuerzos en la red cristalina y la reducción del tamaño promedio de los granos, lo que permitió establecerlos mecanismos de endurecimiento del acero AISI 1045, deformado por rodadura. Fueron medidos yanalizados diferentes puntos teniendo en cuenta los índices de Miller para la fase ferrítica del acero. Losmodelos lineales obtenidos, son estadísticamente significativos, que muestran una tendencia creciente delas propiedades mecánicas y metalúrgicas, según se incrementan las variables independientes delproceso de experimentación.Palabras claves: rodillo, rodadura, deformación plástica.__________________________________________________________________AbstractThe objective of the paper is to carry out the analysis from the tensions to steel samples AISI 1045hardened cold for roller. With employment of the method of Willianson-Hall was determined the macro andmicro deformations; the reticular deformation of the net parameter; the size of the crystallites; the efforts inthe crystalline net and the reduction of the size average of the grains, what allowed to establish themechanisms of hardening of the steel AISI 1045, deformed by rolling. They were measured and analyzeddifferent points keeping in mind the indexes of Miller for the phase ferrite of the steel. The obtained linealmodels, they are statistically significant that they show a growing tendency of the mechanical estates andmetallurgical, as the independent variables of the experimentation process are increased.Key words: roller, rolling, plastic deformation.

  16. Fretting fatigue in AISI 1015 steel

    Indian Academy of Sciences (India)

    R Gnanamoorthy; R Rosi Reddy

    2002-04-01

    A small osillatory movement between two contacting surfaces is termed as fretting and on many occasions it acts as the crack initiation site leading to catastrophic failure of the overall structure. The occurrence of fretting is observed in many engineering structures such as shaft flanges, gas turbines, steel ropes etc. An experimental facility, which can simulate the fretting fatigue in many engineering applications, is the primary requirement of the research program. A laboratory fretting fatigue test facility capable of varying many influencing parameters of fretting fatigue such as slip amplitutde, frequency, contact pressure, etc is designed and developed. Preliminary investigations on plain and fretting fatigue behaviour of AISI 1015 structural steel are reported in this paper. A strength reduction factor of about 1.30 was obtained due to fretting for the test material under the present experimental conditions. Influence of contact load on fretting was also studied. Increasing fretting contact load decreased the fatigue life in the range investigated. Failure analysis showed typical stage I oblique crack growth followed by stage II straight crack perpedicular to the fretting zone.

  17. Optimization of tensile strength of friction welded AISI 1040 and AISI 304L steels according to statistics analysis (ANOVA)

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Ozdemir, Niyazi; Firat, Emrah Hanifi; Caligulu, Ugur [Firat Univ., Elazig (Turkey)

    2013-06-01

    Materials difficult to weld by fusion welding processes can be successfully welded by friction welding. The strength of the friction welded joints is extremely affected by process parameters (rotation speed, friction time, friction pressure, forging time, and forging pressure). In this study, statistical values of tensile strength were investigated in terms of rotation speed, friction time, and friction pressure on the strength behaviours of friction welded AISI 1040 and AISI 304L alloys. Then, the tensile test results were analyzed by analysis of variance (ANOVA) with a confidence level of 95 % to find out whether a statistically significant difference occurs. As a result of this study, the maximum tensile strength is very close, which that of AISI 1040 parent metal of 637 MPa to could be obtained for the joints fabricated under the welding conditions of rotation speed of 1700 rpm, friction pressure of 50 MPa, forging pressure of 100 MPa, friction time of 4 s, and forging time of 2 s. Rotation speed, friction time, and friction pressure on the friction welding of AISI 1040 and AISI 304L alloys were statistically significant regarding tensile strength test values. (orig.)

  18. Influencia de los regímenes de lubricación en la vida de la herramienta y el acabado superficial del fresado de aceros endurecidos AISI D2 y AISI D6

    Directory of Open Access Journals (Sweden)

    Maritza Mariño-Cala

    2015-10-01

    Full Text Available Se realizó un análisis de la calidad superficial y la vida de la herramienta durante el mecanizado con altas velocidades de los aceros endurecidos AISI D2 y AISI D6, en dos regímenes de lubricación. Los ensayos fueron realizados en un centro de mecanizado MORI SEIKI SV 40 y se emplearon herramientas intercambiables de metal duro recubiertas. La evaluación de la calidad superficial se realizó mediante el monitoreo off-line de la rugosidad superficial media Ra en el sentido del avance y perpendicular a este. La progresión del desgaste en las herramientas se analizó a través de un estereoscopio montado en conjunto con una cámara fotográfica digital interconectada a un programa analizador de imágenes. La aplicación de corte seco en operaciones de fresado de aceros endurecidos con altas velocidades apunta hacia una disminución de los costos del proceso asociados al uso de líquidos lubricantes y su reciclaje y a un aumento de la calidad superficial de la pieza y la vida de la herramienta.

  19. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    OpenAIRE

    Thanee Toomprasen; Chawalit Thinvongpituk; Sukangkana Talangkun

    2014-01-01

    This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grain...

  20. Thermomechanical behaviour of AISI 304 steels; Comportamiento termomecanico de aceros AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    El Wahabi, M.; Garcia, V. G.; Cabrera, J. M.; Prado, J. M.

    2001-07-01

    The hot deformation behaviour of three AISI 304 (H, L and HP) austenitic stainless steel with different carbon contents has been studied. An analysis of the parameters describing their hot flow curves was carried out. No heavy effect of the carbon content was found on most of the latter parameters. However, the work hardening and dynamic recovery behaviour showed clear differences depending on the given alloy, especially at high temperatures and low strain rates where the high carbon steel displayed larger work hardening and dynamic recovery rates than the other steels. The high purity steel (interstitial free) displayed the lower stress levels as its hardening rate was slower than in the other two steels. (Author) 16 refs.

  1. The study on the properties of AISI 4140 and AISI 1040 steel rods welded by friction welding

    Directory of Open Access Journals (Sweden)

    Thanee Toomprasen

    2014-06-01

    Full Text Available This paper is aimed to investigate the properties of joint between AISI 4140 and AISI 1040 welded by friction welding. The specimens were prepared in round shape of 13 mm diameter and 100 mm long. They were welded by friction welding method under the following conditions; friction pressure of 183 MPa, friction time of 12 sec, upset pressure of 428 MPa, upset time of 7 sec. and rotational speed of 1400 rpm. The strength and hardness were tested on the welded area. The result showed finer grains. in the welded area. This is the result of friction pressure and upset pressure in the welding process. In addition, the observation result indicated some changes of Ferrite and Pearlite in welded zone. This phase change resulted in the increment of hardness in AISI 4140 at the contact area and adjacent. In part of AISI 1040, the portion of Pearlite and Ferrite are not significantly changed, therefore the value of hardness is almost constant.

  2. Influence of oil and water media on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel

    Institute of Scientific and Technical Information of China (English)

    REN Ping-di; CHEN Guang-xiong; ZHU Min-hao; ZHOU Zhong-rong

    2004-01-01

    A series of fretting test were carried out using a DELTA PLINT testing system to study the influence of hydraulic oil and water on fretting behaviour of AISI 52100 steel rubbing against AISI 1045 steel. The test result shows that media hydraulic oil and water have a distinct influence on fretting behaviour of the tested materials. Medium water can lead to shifting of the partial slip regime in the fretting map from a larger displacement amplitude toward a smaller one and enlargement of the mixed slip regime, in comparison with that in ambient atmosphere. While medium hydraulic oil can result in shifting of the partial slip regime from a smaller displacement amplitude toward a larger one. In the gross slip regime, hydraulic oil and water play a positive role as lubrication media. They can clearly decrease the fretting friction coefficient between AISI 52100 and AISI 1045. The test result also demonstrates that this lubrication effect will get better with increasing displacement amplitude and that hydraulic oil is better than water for lubrication. SEM observation of the wear scars displays that the fretting wear mainly results from abrasive wear and delamination of the fretted materials when using these two kinds of substances as lubrication media.

  3. Tratamiento térmico del acero inoxidable ferrítico AISI 430L sinterizado en atmósfera de N2-H2

    Directory of Open Access Journals (Sweden)

    Ruiz-Prieto, J. M.

    2005-12-01

    Full Text Available In this Work the influence of sintering AISI 430L stainless steel in N2-H2 atmosphere on its properties and microstructure have been studied. The presence of nitrogen in the sintering atmosphere leads to complex nitrides formation the AISI 430L sintered steel microstructure. A subsequent heat treatment was applied to modify this microstructure in order to improve the mechanical properties and corrosion resistance of these ferritic stainless steels.Los aceros inoxidables ferríticos, son aceros que contienen esencialmente cromo (12-30 % junto con níquel y molibdeno en cantidades que, en general, no sobrepasan el 1 % y, en ocasiones, se les adicionan otros elementos como son el aluminio, silicio, titanio o niobio. En el presente trabajo de investigación se ha evaluado la influencia del nitrógeno presente en la atmósfera de sinterización sobre la microestructura y propiedades del acero inoxidable ferrítico AISI 430L. Además, se ha realizado un tratamiento térmico posterior de hipertemple y maduración con el objeto de incrementar las propiedades mecánicas y a corrosión de este acero inoxidable, mediante la modificación microestructural de los nitruros complejos de hierro y cromo precipitados durante la etapa de sinterización.

  4. Tribological and corrosion behaviors of carburized AISI 4340 steel

    Science.gov (United States)

    Thong-on, Atcharawadi; Boonruang, Chatdanai

    2016-01-01

    AISI 4340 steel is widely used in automotive and aircraft industries as gear components. In such applications, surface hardening processes such as carburizing are required in order to improve the life time of the components. There are many studies showing the tribological behavior of the carburized steel, but the corrosion behavior has not yet been clarified. This paper reports on both tribological and corrosion behaviors of the carburized AISI 4340 steel. Factor associated with carburizing, such as the quantities of deposited carbon, dissolved carbon, and formed Cr23C6 and Fe3C, affect the tribological and corrosion behaviors of the steel by improving hardness, friction, lubrication, and wear resistance; but corrosion resistance is reduced. The dissolved carbon affects the formation of the oxide layer of the carburized steel, by obstructing the continuous oxide layer formation and by decreasing the chromium content of the steel, leading to the decrease in the corrosion resistance of the steel.

  5. Magnetic Barkhausen emission in lightly deformed AISI 1070 steel

    Energy Technology Data Exchange (ETDEWEB)

    Capo Sanchez, J., E-mail: jcapo@cnt.uo.edu.cu [Departamento de Fisica, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n, 90500 Santiago de Cuba (Cuba); Campos, M.F. de [EEIMVR-Universidade Federal Fluminense, Av. dos Trabalhadores 420, Vila Santa Cecilia, 27255-125 Volta Redonda, RJ (Brazil); Padovese, L.R. [Departamento de Engenharia Mecanica, Escola Politecnica, Universidade de Sao Paulo, Av. Prof. Mello Moraes, 2231, 05508-900 Sao Paulo (Brazil)

    2012-01-15

    The Magnetic Barkhausen Noise (MBN) technique can evaluate both micro- and macro-residual stresses, and provides indication about the relevance of contribution of these different stress components. MBN measurements were performed in AISI 1070 steel sheet samples, where different strains were applied. The Barkhausen emission is also analyzed when two different sheets, deformed and non-deformed, are evaluated together. This study is useful to understand the effect of a deformed region near the surface on MBN. The low permeability of the deformed region affects MBN, and if the deformed region is below the surface the magnetic Barkhausen signal increases. - Highlights: > Evaluated residual stresses by the magnetic Barkhausen technique. > Indication about the relevance of micro-and macro-stress components. > Magnetic Barkhausen measurements were carried out in AISI 1070 steel sheet samples. > Two different sheets, deformed and non-deformed, are evaluated together. > Magnetic Barkhausen signal increases when deformed region is below the surface.

  6. Dense plasma focus-assisted nitriding of AISI-304

    Science.gov (United States)

    Shafiq, M.; Asghar, M.; Ahmad, S.; Sadiq, M.; Qayyum, A.; Zakaullah, M.

    Nitrogen ion implantation into AISI-304 stainless steel is carried out using a dense plasma focus device, operated at a charging voltage of 18 kV (discharge energyD1.45 kJ) with nitrogen filling at optimum pressure of 0.75 mbar. AISI-304 stainless steel samples placed axially above the anode tip are exposed to the ions for 10, 20 and 30 focus shots. X-ray diffraction (XRD), Vickers's micro hardness tester, scanning electron microscopy, and energy dispersive X-ray spectroscopy are used to explore the ion induced changes in the crystallographic structures, surface morphology, elemental composition and surface hardness of the ion irradiated samples. The XRD pattern confirms the formation of an expanded austenite phase, owing to nitrogen incorporated into the existing iron lattice. The results of micro hardness tester show that the hardness is increased about three times at an axial distance of 5 cm for 20 shots.

  7. Laser Welding Of Thin Sheet Of AISI 301 Stainless Steel

    Science.gov (United States)

    Vilar, R.; Miranda, R. M.

    1989-01-01

    Preliminary results of an investigation on laser welding of AISI 301 stainless steel thin sheet are presented. Welds were made with a CO2 continuous wave laser, varying power density and welding speed. The welds were studied by optical and electron scanning microscopy, X-ray diffraction and hardness tests. Experimental results show that under appropriate conditions, sound welds are obtained, with a negligeable heat affected zoneanda fine microstructure in the fusion zone. The fusion zone shows a cellular - dendritic microstructure, with austenite and ferrite as the major constituents. Ferrite, whose content is 5 to 7%, is predominantly intradendritic with both vermicular and acicular morphologies. However some interdendritic ferrite may also be present. The characteristics of the structure suggest that the solidification mode of AISI 301 stainless steel is essentially ferritic.

  8. Weldability of AISI 304 to copper by friction welding

    Energy Technology Data Exchange (ETDEWEB)

    Kirik, Ihsan [Batman Univ. (Turkey); Balalan, Zulkuf [Firat Univ., Elazig (Turkey)

    2013-06-01

    Friction welding is a solid-state welding method, which can join different materials smoothly and is excessively used in manufacturing industry. Friction welding method is commonly used in welding applications of especially cylindrical components, pipes and materials with different properties, for which other welding methods remain incapable. AISI 304 stainless steel and a copper alloy of 99.6 % purity were used in this study. This couple was welded in the friction welding machine. After the welding process, samples were analyzed macroscopically and microscopically, and their microhardness was measured. Tensile test was used to determine the bond strength of materials that were joined using the friction welding method. At the end of the study, it was observed that AISI 304 stainless steel and copper could be welded smoothly using the friction welding method and the bond strength is close to the tensile strength of copper. (orig.)

  9. Laser surface hardening of AISI H13 tool steel

    Institute of Scientific and Technical Information of China (English)

    Jae-Ho LEE; Jeong-Hwan JANG; Byeong-Don JOO; Young-Myung SON; Young-Hoon MOON

    2009-01-01

    An attempt was made to improve the surface hardness and wear properties of AISI H13 tool steel through solid solution hardening and refinement of microstructures using a 200 W fiber laser as a heat generating source. The hardness of laser melted zone was investigated. In order to identify the effect of heat input on the laser melting zone, scanning conditions were controlled. The results show that, the hardness of as-received AISI H13 tool steel is approximately Hv 240, and the hardness after laser surface heat treatment is around Hv 480-510. The hardening depth and width are increased with the increase in the heat input applied. Application of experimental results will be considered in tooling industry.

  10. The aluminizing in powder technology of AISI 304 steel

    Science.gov (United States)

    Băitanu, D. B.; Găluşcă, D. G.; Achiţei, D. C.; Minciună, M. G.; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    The paper presents a study about the aluminizing treatments applied to AISI 304 stainless steel, with the purpose to improve the corrosion resistance. The aluminizing is realized in a powder medium, composed by aluminium powder (with 99.95% purity), aluminium oxide Al2O3 and ammonium chloride NH4Cl. The structural characterization was made by scanning electronic microscopy to highlight the structure of layer after aluminizing, at different magnitudes.

  11. Cutting Forces Analysis in Additive Manufactured AISI H13 Alloy

    OpenAIRE

    Montevecchi, Filippo; Grossi, Niccolò; Takagi, Hisataka; Scippa, Antonio; Sasahara, Hiroyuki; Campatelli, Gianni

    2016-01-01

    Combining Additive Manufacturing (AM) and traditional machining processes is essential to meet components functional requirements. However significant differences arise in machining AM and wrought parts. Previous works highlighted the increasing of tool wear and worse surface finish. In this paper cutting forces are investigated as an indicator of material machinability. Milling cutting force coefficients are identified using mechanistic approach, comparing AISI-H13 wrought and AM specimen. C...

  12. Recubrimientos de (ti,aln sobre acero aisi 4140 por sputtering reactivo

    Directory of Open Access Journals (Sweden)

    DANNA GARCIA

    2007-01-01

    Full Text Available Empleando la técnica de Pulverización catódica con radiofrecuencia y magnetrón (Magnetron Sputtering RF, se prepararon películas de (Ti,AlN sobre sustratos de acero AISI 4140. Se utilizó un blanco formado con polvos metálicos de Ti y Al, con composición nominal 60% Ti y 40% Al (porcentaje en átomos y una razón de presiones parciales de nitrógeno - argón, PN2/PAr de 0,1 aproximadamente; la temperatura del sustrato se varió entre 260 y 330 ºC y el tiempo de deposición entre 2 y 4,5 horas para obtener películas con diferentes espesores. La composición química de las películas se determinó mediante la técnica de energía dispersada de rayos X (EDX, y su topografía mediante microscopía de fuerza atómica (AFM. Igualmente se midió micro dureza, y se determinó su comportamiento electroquímico mediante espectroscopia de impedancia electroquímica EIS y ensayos TAFEL. Las películas obtenidas presentaron granos globulares, uniformes y de pequeño diámetro, con características electroquímicas de protección al sustrato frente a procesos de corrosión.

  13. Mössbauer studies on an AISI 1137 type steel

    Indian Academy of Sciences (India)

    E Güler; H Akta

    2006-06-01

    An AISI 1137 type medium carbon steel was studied by means of scanning electron microscopy and Mössbauer spectroscopy. This steel in as received state at room temperature was ferritic. Different heat treatments on related steel exhibited different microstructures such as pearlite and bainite. Also magnetism of these product phases was determined as 32.7 T and 32.6 T relatively where ferromagnetism of ferritic phase in as received state was 33.05 T. Mössbauer parameters such as isomer shifts and % volumes were also determined before and after transformations.

  14. A study of cumulative fatigue damage in AISI 4130 steel

    Science.gov (United States)

    Jeelani, S.; Musial, M.

    1986-01-01

    Experimental data were obtained using AISI 4130 steel under stress ratios of -1 and 0. A study of cumulative fatigue damage using Miner's and Kramer's equations for stress ratios of -1 and 0 for low-high, low-high-mixed, high-low, and high-low-mixed stress sequences has revealed that there is a close agreement between the theoretical and experimental values of fatigue damage and fatigue life. Kramer's equation predicts less conservative and more realistic cumulative fatigue damage than the popularly used Miner's rule does.

  15. Glow Discharge Plasma Nitriding of AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    A.QAYYUM; M.A.NAVEED; S.ZEB; G.MURTAZA; M.ZAKAULLAH

    2007-01-01

    Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis.The treated samples were analysed by X-ray diffraction(XRD)to explore the changes induced in the crystallographic structure.The XRD pattern confirmed the formation of an expanded austenite phase(γN)owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice.A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth(μm).The results showed clear evidence of surface changes with substantial increase in surface hardness.

  16. Transformaciones Microestructurales en Soldaduras Disímiles de Acero Inoxidable Austenítico con Acero Inoxidable Ferrítico

    OpenAIRE

    Sara María Aguilar-Sierra; Claudia Patricia Serna-Giraldo; Ricardo Emilio Aristizábal-Sierra

    2015-01-01

    En este trabajo se estudian los fenómenos metalúrgicos que ocurren en la soldadura SMAW de un acero inoxidable ferrítico AISI 430 con un acero inoxidable austenítico AISI 316L. Para el estudio se utilizaron dos tipos de electrodos: austenítico AWS E309L y dúplex AWS E2209-16, ambos con un diámetro de 3,2 mm. Las uniones soldadas se realizaron con un solo pase y se variaron simultáneamente la corriente y la velocidad de soldadura; las condiciones fueron ...

  17. COMPARACIÓN DEL COMPORTAMIENTO AL DESGAS TE DE UN ACERO AISI 1045 NITRURADO Y SEGUIDO DE UN TEMPLE POR INDUCCIÓN

    OpenAIRE

    Gonzalo J. Schierloh; Matías Regis; Raúl Charadia; Eugenia L. Dalibon; Sonia P. Brühl

    2016-01-01

    Se estudió el comportamiento al desgaste de l acero AISI1045 con un tratamiento de nitruración iónica y posterior temple por inducción. Se midió dureza en superficie y perfil en profundidad. Se analizó la microestructura y evaluó el comportamiento al desgaste . Como resultado de la nitruración se obtuvo una zona formada por una capa de compuestos seguida por una zona de difus ión de nitrógeno. L a dureza superficial del acero templado y revenido aumentó en un...

  18. Diffusional Growth Kinetics Analisys of Fe2B Layers Applied During the Coating Powder-Pack Boriding Process on an AISI 1026 Steel

    OpenAIRE

    2015-01-01

    La exigencia de emplear materiales con propiedades avanzadas incluyen la necesidad de aplicar recubrimientos de alta resistencia que alarguen la vida de útil de aceros comerciales, de esta forma, el tratamiento termoquímico de borurización tiene el potencial para cumplir estos requerimientos. En este trabajo de investigación se formula un modelo matemático para analizar la cinética de crecimiento de las capas de 2 Fe B formadas sobre la superficie de un acero AISI 1026. El modelo matemático p...

  19. PERFORMANCE STUDY ON AISI316 AND AISI410 USING DIFFERENT LAYERED COATED CUTTING TOOLS IN CNC TURNING

    Directory of Open Access Journals (Sweden)

    K. RAJA

    2015-01-01

    Full Text Available Stainless steel (SS is used for many commercial and industrial applications owing to its high resistance to corrosion. It is too hard to machine due to its high strength and high work hardening property. A surface property such as surface roughness (SR is critical to the function-ability of machined components. SS is generally regarded as more difficult to machine material and poor SR is obtained during machining. In this paper an attempt has been made to investigate the SR produced by CNC turning on austenitic stainless steel (AISI316 and martensitic stainless steel (AISI410 by different cases of coated cutting tool used at dry conditions. Multilayered coated with TiCN/Al2O3, multilayered coated with Ti(C, N, B and single layered coated with TiAlN coated cutting tools are used. Experiments were carried out by using Taguchi’s L27 orthogonal array. The effect of cutting parameters on SR is evaluated and optimum cutting conditions for minimizing the SR are determined. Analysis of variance (ANOVA is used for identifying the significant parameters affecting the responses. Confirmation experiments are conducted to validate the results obtained from optimization.

  20. Evaluación del coeficiente de endurecimiento del acero AISI 1045 deformado por rodillo

    Directory of Open Access Journals (Sweden)

    D. Alcántara

    2011-12-01

    Full Text Available El objetivo del trabajo es determinar el comportamiento del coeficiente de endurecimiento n por la ecuación de Hollomon en muestras cilíndricas de acero AISI 1045, las cuales, después de ser deformadas, se sometieron a ensayos de tracción. Se utiliza un diseño de experimento donde se tienen en cuenta las variables número de revolución (n con 27, 54 y 110 rev/min, fuerza de compresión (P de 500, 1 500 y   2 500 N y avance (S de 0,075; 0,125 y 0,25 mm/rev. Finalmente, aplicando el método de regresión se obtuvo un coeficiente de endurecimiento, el cual se aproxima a la linealidad cuando restringimos el cálculo a rangos de deformación elevados. Este coeficiente de endurecimiento se aplica en la ecuación de Hollomon para determinar el nuevo valor de tensión de fluencia y aplicarlo para el cálculo del trabajo mínimo a realizar en un proceso de deformación en frío empleando rodillo simple.   Palabras clave: Deformación Plástica; tensión; deformación; endurecimiento.The objective of the work is to determine the behavior of the hardening coefficient n by the equation of Hollomon, in cylindrical samples of steel AISI 1045, those which, after the deformed, were subjected to traction rehearsals. He used an experiment design where are kept in mind the revolution number (n with 27, 54 and 110 rev/min, it compression forces (P of 500, 1 500 and 2 500 N and feed (S of 0.075; 0.125 and 0.25 mm/rev. Finally, applying the regression method a hardening coefficient was obtained, which approaches to the linearity when restrict the calculation to high ranges of deformation. This hardening coefficient is applied in the equation of Hollomon for determine the new value of flow tension and to apply in the calculation of the minimum work to carry out in a cold process of deformation using simple roller.   Keywords: Plastic deformation; stress; deformation; hardening.

  1. Plasma nitriding of AISI 304L and AISI 316L stainless steels: effect of time in the formation of S phase and the chromium nitrides; Nitretacao a plasma dos acos inoxidaveis AISI 304L e AISI 316L: efeito do tempo na formacao da fase S e dos nitretos de cromo

    Energy Technology Data Exchange (ETDEWEB)

    Souza, D.A. de; Barbosa, G.C.; Pinto, F.A.M.; Gontijo, L.C. [Instituto Federal de Educacao, Ciencia e Tecnologia do Espirito Santo - IFES, Vitoria, ES (Brazil); Canal, G.P.; Cunha, A.G., E-mail: disouzam@yahoo.com.br [Universidade Federal do Espirito Santo (UFES), Vitoria, ES (Brazil). Dept. de Fisica

    2009-07-01

    Plasma nitriding can improve hardness and wear resistance of austenitic stainless steels without losses in corrosion resistance. This fact relies on a nitrided layer constituted only by S phase, without chromium nitrides precipitation. In this work, the effect of nitriding time on phases formed on nitrided layer was investigated in two austenitic stainless steels: AISI 304L e AISI 316L. The samples were nitrided at 420 deg C, using a mixture of 60 % N{sub 2} and 40% H{sub 2}, during 5, 7 and 9 hours. It was noted that chromium nitrides were formed on samples of AISI 304L, nitrided for 7 e 9 hours, while all nitrided samples of AISI 316L showed only formation of S phase. The nitrided layers were characterized using optical microscope and x-ray diffraction. (author)

  2. Investigation of Machinability Characteristics of AISI 316Ti Stainless Steel

    Directory of Open Access Journals (Sweden)

    Yunus Kayır

    2012-01-01

    Full Text Available In this study, many experiments of machinability were carried out on universal turning lathe. The cutting forces that occur during machining of workpieces were measured. A standard dynamometer was used to measure cutting forces. The Dynamometer were assembled on the lathe efficiently. An apart were designed and machined to assembly the dynamometer. Moreover, AISI 316Ti stainless steel parts were turned by carbide cutting tools coated with TiAlN components. Effects of cutting tools with different radius on cutting forces and surface roughness were investigated by using different cutting parameters. Moreover, machined parts' surface roughness was controlled. The experimental results showed that cutting forces increased with the increasing federate, but the surface roughness decreased with increasing the radius of cutting edge.

  3. COLD ROLLING ORTHODONTIC WIRES OF AUSTENITIC STAINLESS STEEL AISI 304

    Directory of Open Access Journals (Sweden)

    Rodrigo Santos Messner

    2013-03-01

    Full Text Available Austenitic stainless steels wires are widely used in the final stages of orthodontic treatment. The objective of this paper is to study the process of conformation of rectangular wires from round wires commercial austenitic stainless steel AISI 304 by the process of cold rolling. The wire quality is evaluated by means of dimensional analysis, microhardness measurements, tensile strength and fractographic analysis of the wires subjected to tensile tests. Also a study on the application of finite element method to simulate the process, comparing the force and rolling stress obtained in the rolling is done. The simulation results are consistent with those obtained in the actual process and the rolled wires show ductile fracture, tensile strength and dimensional variations appropriate to orthodontic standards. The fracture morphology shows the model cup-cone type besides the high deformation and hardness inherent in the cold rolling process.

  4. Fretting of AISI 9310 and selected fretting resistant surface treatments

    Science.gov (United States)

    Bill, R. C.

    1977-01-01

    Fretting wear experiments were conducted with uncoated AISI 9310 mating surfaces, and with combinations incorporating a selected coating to one of the mating surfaces. Wear measurements and SEM observations indicated that surface fatigue, as made evident by spallation and surface crack formation, is an important mechanism in promoting fretting wear to uncoated 9310. Increasing humidity resulted in accelerated fretting, and a very noticeable difference in nature of the fretting debris. Of the coatings evaluated, aluminum bronze with a polyester additive was most effective at reducing wear and minimizing fretting damage to the mating uncoated surface, by means of a selflubricating film that developed on the fretting surfaces. Chromium plate performed as an effective protective coating, itself resisting fretting and not accelerating damage to the uncoated surface.

  5. The Study of Plasma Nitriding of AISI304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    WANG Liang; JI Shi-jun; GAO Yu-zhou; SUN Jun-cai

    2004-01-01

    This paper presents results on the plasma nitriding of AISI 304 stainless steel at different temperatures in NH 3 gas. The working pressure was 100~200 Pa and the discharge voltage was 700~800V. The phase of nitrided layer formed on the surface was confirmed by X-ray diffraction. The hardness of the samples was measured by using a Vickers microhardness tester with the load of 50g. After nitriding at about 400 ℃ for two hours a nitrided layer consisting of single γN phase with thickness of 5μm was obtained. Microhardness measurements showed significant increase in the hardness from 240 HV (for untreated samples) up to 950 HV (for nitrided samples at temperature of 420℃). The phase composition, the thickness, the microstructure and the surface topography of the nitrided layer as well as its properties depend essentially on the process parameters.

  6. Experimental survey on the behaviour of AISI 304 steel sheets subjected to perforation

    OpenAIRE

    2010-01-01

    This paper presents and analyzes the behaviour of AISI 304 steel sheets subjected to perforation under a wide range of impact velocities. The relevance of this steel resides in the potential transformation of austenite into martensite during mechanical loading. This process leads to an increase in strength and ductility of the material. It makes the AISI 304 attractive for many engineering applications, especially for building structural elements responsible for absorbing energy under fast lo...

  7. Linear friction welding of AISI 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Bhamji, Imran, E-mail: imran.bhamji@postgrad.manchester.ac.uk [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Preuss, Michael [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Threadgill, Philip L. [Formerly with TWI Ltd., Cambridge, UK (now retired) (United Kingdom); Moat, Richard J. [Manchester Materials Science Centre, University of Manchester, Grosvenor Street, M1 7HS (United Kingdom); Addison, Adrian C. [TWI Ltd., Cambridge (United Kingdom); Peel, Matthew J. [University of Bristol, Queens Building, University Walk, Bristol BS8 1TR (United Kingdom)

    2010-12-15

    Research highlights: {yields} Linear friction welding is a feasible process for joining AISI316L. {yields} Most welds had tensile strengths superior to the parent material. {yields} Welding parameters had a significant impact on weld microstructure. {yields} Control of microstructure by controlling welding parameters is a process benefit. - Abstract: Linear friction welding is a solid state joining process established as a niche technology for the joining of aeroengine bladed disks. However, the process is not limited to this application, and therefore the feasibility of joining a common engineering austenitic steel, AISI 316L, has been explored. It was found that mechanically sound linear friction welds could be produced in 316L, with tensile properties in most welds exceeding those of the parent material. The mechanical properties of the welds were also found to be insensitive to relatively large changes in welding parameters. Texture was investigated in one weld using high energy synchrotron X-ray diffraction. Results showed a strong {l_brace}1 1 1{r_brace}< 1 1 2 > type texture at the centre of the weld, which is a typical shear texture in face centre cubic materials. Variations in welding parameters were seen to have a significant impact on the microstructures of welds. This was particularly evident in the variation of the fraction of delta ferrite, in the thermo-mechanically affected zone of the welds, with different process parameters. Analysis of the variation in delta ferrite, with different welding parameters, has produced some interesting insights into heat generation and dissipation during the process. It is hoped that a greater understanding of the process could help to make the parameter optimisation process, when welding 316L as well as other materials, more efficient.

  8. Austenitic Stainless Steel AISI 316L Corrosion Test Research%奥氏体不锈钢AISI 316L腐蚀试验研究

    Institute of Scientific and Technical Information of China (English)

    王金刚; 刘江涛; 程珊珊

    2014-01-01

    在精对苯二甲酸(PTA)生产中,选取干燥机BM302壳体常用材料奥氏体不锈钢AISI 316L为研究对象,在醋酸环境中,对AISI 316L 受Br-及Cl-作用的电化学极化试验和电化学阻抗试验进行腐蚀性试验研究。试验结果表明,Br-或Cl-浓度的增加都会导致AISI 316L不锈钢腐蚀速率增加、击穿电位降低、腐蚀反应电阻减小,导致其耐腐蚀性能下降,腐蚀加剧。为PTA设备腐蚀的现场监测和设备维护提供参考依据。%In purified terephthalic acid (PTA) production, selected the drying machine BM302 shell commonly use material austenitic stainless steel AISI 316L as the research object. In the acetic acid environment, for corrosive test research of AISI 316L, through Br-and Cl-the role of electrochemical polarization test and electrochemical impedance test. The test results show that Br-or Cl-will lead to the increasing of the concentration of seawater AISI 316L stainless steel corrosion rate increase, breakdown voltage is reduced, and the corrosion reaction resistance decreases, and lead to its corrosion resistance drop, corrosion intensifies. That will provide reference for PTA equipment corrosion field monitoring and equipment maintenance.

  9. Caracterización microestructural de uniones soldadas de acero AISI 316L en tuberías

    Directory of Open Access Journals (Sweden)

    Tomás H. Fernández-Columbié

    2016-03-01

    Full Text Available Se analizó el comportamiento microestructural de uniones soldadas de acero AISI 316L empleado en la fabricación de tuberías, las cuales se ven afectadas por agrietamiento en el cordón de soldadura. Se emplearon electrodos revestidos de acero inoxidables de los tipos E 309–16; 310–16 y E 316L–16, según norma de la AWS, los que fueron evaluados por su depósito en uniones a tope preparadas con biseles en V, soldadas por un solo lado del material de la tubería, así como la selección y preparación de muestra en zonas donde la tubería presenta daños mecánicos, fisuras y corrosión severa con pérdida del espesor de pared crítica para soportar las presiones de trabajo. Se caracterizó la microestructura de la zona fundida y la zona de influencia térmica de cada cordón luego de realizado el proceso de soldadura. Se concluye que la soldadura con electrodos del tipo E 309-16 y del tipo E 316-16 no son recomendables debido a que se obtiene una microestructura sensible al agrietamiento.

  10. Síntesis y caracterización de recubrimientos de tin, tic y ticn sobre acero aisi 4340

    Directory of Open Access Journals (Sweden)

    Héctor E. Jaramillo Suárez

    2004-01-01

    Full Text Available En este trabajo se crecieron películas de TiN, TiC y TiCN sobre aceros AISI 4340, con el objeto de comparar los resultados estructurales, morfológicos y mecánicos al crecerlos sobre un mismo substrato. Se utilizó un láser pulsado Nd: YAG con energía de 500mJ, longitud de onda de 1064 nm y tasa de repetición de 10 Hz. Mediante microscopia de Fuerza Atómica AFM, se observó que los recubrimientos presentan alta homogeneidad y tamaño de grano fino. Por Microscopía Electrónica de Barrido se determinó presencia de microgotas en los recubrimientos. Se aplicó prueba de tensión para determinar la adhesión de las películas; aplicando cargas máximas de 60 Kgf, los recubrimientos no mostraron señales de desprendimiento del substrato. A todos los recubrimientos se les sometió a prueba de dureza Rockwell C, con el fin de determinar la resistencia a la fractura, indicando que estos recubrimientos son aptos para diferentes aplicaciones en la industria.

  11. Evaluación del grado de sensibilización en el acero inoxidable AISI

    Directory of Open Access Journals (Sweden)

    González, O.

    2003-12-01

    Full Text Available Austenitic stainless steel, when heat-treated at 550-850 °C, became susceptible to intergranular corrosion in acids. This phenomenon, know as sensitization, it is result from the precipitation of chrome carbides in the grain boundary, making these areas less resistant to corrosion. Two different electrochemical reactivation tests are compared with a destructive test and related to the classification of its respective microstructures. It was established a quantitative methodology to evaluate the degree of sensitization in AISI 304 and also to compare the correspondence of the results with the data of the automatic and portable EPR device for non-destructive field measurement of the degree of sensitization. The used electrochemical techniques were the EPR (Electrochemical Potentiokinetic Reactivation or single loop test and the PRP (Pasivation Reactivation Potentiokinetic or double loop test. The destructive test used was boiling, 120 h ferric sulfate-50 % sulfuric acid, according to the standard practices ASTM A-262 practices B. The classifications of each structures were according to the standard practices ASTM A-262 practices B.

    El acero inoxidable austenítico, cuando se calienta en un rango de temperatura entre 550 y 850 °C es susceptible a corrosión intergranular en ácidos. Este fenómeno, conocido como sensibilización, es resultado de la precipitación de carburos de cromo en el límite de grano, haciendo esas áreas menos resistentes a la corrosión. Se comparan dos pruebas diferentes de reactivación electroquímica con una prueba destructiva, relacionándolas con su respectiva microestructura. Se estableció una metodología cuantitativa para evaluar el grado de sensibilización del acero AISI 304 y se comparó con los datos generados de una herramienta no destructiva de campo, automática y portátil, para medir el grado de sensibilización. Las técnicas electroquímicas usadas fueron: la EPR (Reactivación electroqu

  12. Corrosion and microstructural analysis data for AISI 316L and AISI 347H stainless steels after exposure to a supercritical water environment

    Directory of Open Access Journals (Sweden)

    A. Ruiz

    2016-06-01

    Full Text Available This article presents corrosion data and microstructural analysis data of austenitic stainless steels AISI 316L and AISI 347H exposed to supercritical water (25 MPa, 550 °C with 2000 ppb of dissolved oxygen. The corrosion tests lasted a total of 1200 h but were interrupted at 600 h to allow measurements to be made. The microstructural data have been collected in the grain interior and at grain boundaries of the bulk of the materials and at the superficial oxide layer developed during the corrosion exposure.

  13. Physical properties of the AISI 348 L{sup *} austenitic stainless steel; Propriedades fisicas do aco inoxidavel austenitico AISI 348 L{sup *}

    Energy Technology Data Exchange (ETDEWEB)

    Teodoro, Celso Antonio; Lucki, Georgi; Silva, Jose Eduardo Rosa da; Terremoto, Luis Antanio Albiac; Castanheira, Myrthes; Damy, Margaret de Almeida [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil)]. E-mail: cteodoro@ipen.br

    2005-07-01

    The study of radiation damage in metals and alloys, used as structural materials of nuclear reactors has a strategic meaning in nuclear technology, because it allows the performance evaluation of these materials in working conditions of PWR. For this sake it is necessary to know the detrimental structural changes that occur during fast neutron irradiation. The aim of the present work is to show some strain-stress results of the AISI 348 L{sup *} stainless steel utilized as a structural material of the fuel elements of PWR, in comparison with the AISI 304. (author)

  14. Corrosion and microstructural analysis data for AISI 316L and AISI 347H stainless steels after exposure to a supercritical water environment.

    Science.gov (United States)

    Ruiz, A; Timke, T; van de Sande, A; Heftrich, T; Novotny, R; Austin, T

    2016-06-01

    This article presents corrosion data and microstructural analysis data of austenitic stainless steels AISI 316L and AISI 347H exposed to supercritical water (25 MPa, 550 °C) with 2000 ppb of dissolved oxygen. The corrosion tests lasted a total of 1200 h but were interrupted at 600 h to allow measurements to be made. The microstructural data have been collected in the grain interior and at grain boundaries of the bulk of the materials and at the superficial oxide layer developed during the corrosion exposure.

  15. Effects of X-rays Radiation on AISI 304 Stainless Steel Weldings with AISI 316L Filler Material: A Study of Resistance and Pitting Corrosion Behavior

    Directory of Open Access Journals (Sweden)

    Francisco Javier Cárcel-Carrasco

    2016-04-01

    Full Text Available This article investigates the effect of low-level ionizing radiation, namely X-rays, on the micro structural characteristics, resistance, and corrosion resistance of TIG-welded joints of AISI 304 austenitic stainless steel made using AISI 316L filler rods. The welds were made in two different environments: natural atmospheric conditions and a closed chamber filled with inert argon gas. The influence of different doses of radiation on the resistance and corrosion characteristics of the welds is analyzed. Welded material from inert Ar gas chamber TIG showed better characteristics and lesser irradiation damage effects.

  16. Study of residual stresses generated in machining of AISI 4340 steel; Estudo das tensoes residuais geradas na usinagem de aco AISI 4340

    Energy Technology Data Exchange (ETDEWEB)

    Reis, W.P. dos; Fonseca, M.P. Cindra; Serrao, L.F.; Chuvas, T.C.; Oliveira, L.C., E-mail: mcindra@vm.uff.b [Universidade Federal Fluminense (PGMEC/UFF), Niteroi, RJ (Brazil). Dept. de Engenharia Mecanica

    2010-07-01

    Among the mechanical construction steels, AISI 4340 has good harden ability, while combining high strength with toughness and good fatigue strength, making it excellent for application in the metalworking industry, where it can work at different levels and types of requests. Residual stresses are generated in almost all processes of mechanical manufacturing. In this study, the residual stresses generated in different machining processes and heat treatment hardening of AISI 4340 were analyzed by X-ray diffraction, by the sen{sup 2} {psi} method, using Cr{kappa}{beta} radiation and compared. All samples, except for turned and cut by EDM, presented compressive residual stresses in the surface with various magnitudes. (author)

  17. Comparative study of pulsed Nd:YAG laser welding of AISI 304 and AISI 316 stainless steels

    Science.gov (United States)

    Kumar, Nikhil; Mukherjee, Manidipto; Bandyopadhyay, Asish

    2017-02-01

    Laser welding is a potentially useful technique for joining two pieces of similar or dissimilar materials with high precision. In the present work, comparative studies on laser welding of similar metal of AISI 304SS and AISI 316SS have been conducted forming butt joints. A robotic control 600 W pulsed Nd:YAG laser source has been used for welding purpose. The effects of laser power, scanning speed and pulse width on the ultimate tensile strength and weld width have been investigated using the empirical models developed by RSM. The results of ANOVA indicate that the developed models predict the responses adequately within the limits of input parameters. 3-D response surface and contour plots have been developed to find out the combined effects of input parameters on responses. Furthermore, microstructural analysis as well as hardness and tensile behavior of the selected weld of 304SS and 316SS have been carried out to understand the metallurgical and mechanical behavior of the weld. The selection criteria are based on the maximum and minimum strength achieved by the respective weld. It has been observed that the current pulsation, base metal composition and variation in heat input have significant influence on controlling the microstructural constituents (i.e. phase fraction, grain size etc.). The result suggests that the low energy input pulsation generally produce fine grain structure and improved mechanical properties than the high energy input pulsation irrespective of base material composition. However, among the base materials, 304SS depict better microstructural and mechanical properties than the 316SS for a given parametric condition. Finally, desirability function analysis has been applied for multi-objective optimization for maximization of ultimate tensile strength and minimization of weld width simultaneously. Confirmatory tests have been conducted at optimum parametric conditions to validate the optimization techniques.

  18. Microstructural characterization of an AISI-SAE 4140 steel without nitridation and nitrided; Caracterizacion microestructural de un acero AISI-SAE 4140 sin nitrurar y nitrurado

    Energy Technology Data Exchange (ETDEWEB)

    Medina F, A.; Naquid G, C. [Gerencia de Ciencia de Materiales, Depto. de Sintesis y Caracterizacion de Materiales, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2000-07-01

    It was micro structurally characterized an AISI-SAE 4140 steel before and after of nitridation through the nitridation process by plasma post-unloading microwaves through Optical microscopy (OM), Scanning electron microscopy (SEM) by means of secondary electrons and retrodispersed, X-ray diffraction (XRD), Energy dispersion spectra (EDS) and mapping of elements. (Author)

  19. Tensiones de contacto por el método de elementos finitos del acero AISI 1045 endurecido por rodillo

    Directory of Open Access Journals (Sweden)

    Fernández-Columbié, T.

    2012-02-01

    Full Text Available In this paper, the tense-deformational behavior is analyzed by means of simulation using the finite element method for AISI 1045 cold rolled deformed steel. ANYSYS V.10 software was used in this study. Revolution number, compressive strength and tool feed rate were the variables considered in the deformation process. They allowed determining the contact stress of the deformed material. The material used was 30 mm diameter and 100 mm length. Samples of 30 mm diameter and 3 mm thickness were prepared for the optical microscopic observation, which were compared to the results obtained from the simulation. The tensile status of the deformed samples was evaluated as from the reduction of the average size of the grains as per the strength applied. This study intends to show that the cold hardening method is a surface hardening option.

    En el trabajo se analiza el estado tenso-deformacional mediante la simulación por el método de los elemento finitos del acero AISI 1045 deformado en frío empleando rodillo simple, para ello se utilizó el software ANSYS V.10. En el proceso de deformación se consideran las variables número de revolución, la fuerza compresiva y el avance de la herramienta, lo que permitió determinar las tensiones de contacto del material deformado. El diámetro del material empleado fue de 30 mm con una longitud de 100 mm. Para la observación de la microscopía óptica, se prepararon muestras de 30 mm de diámetro por 3 mm de espesor, las que fueron comparadas con los resultados obtenidos de la simulación. El estado tensional de las muestras deformadas se evaluó a partir de la reducción del tamaño promedio de los granos según la fuerza empleada. Con el desarrollo del trabajo se trata de demostrar que el empleo del método de endurecimiento en frío es una alternativa de endurecimiento superficial.

  20. Study on tempering behaviour of AISI 410 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Chakraborty, Gopa, E-mail: gopa_mjs@igcar.gov.in [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Das, C.R.; Albert, S.K.; Bhaduri, A.K.; Thomas Paul, V. [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Panneerselvam, G. [Chemistry Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India); Dasgupta, Arup [Metallurgy & Materials Group, Indira Gandhi Center for Atomic Research, Kalpakkam 603102 (India)

    2015-02-15

    Martensitic stainless steels find extensive applications due to their optimum combination of strength, hardness and wear-resistance in tempered condition. However, this class of steels is susceptible to embrittlement during tempering if it is carried out in a specific temperature range resulting in significant reduction in toughness. Embrittlement of as-normalised AISI 410 martensitic stainless steel, subjected to tempering treatment in the temperature range of 673–923 K was studied using Charpy impact tests followed by metallurgical investigations using field emission scanning electron and transmission electron microscopes. Carbides precipitated during tempering were extracted by electrochemical dissolution of the matrix and identified by X-ray diffraction. Studies indicated that temper embrittlement is highest when the steel is tempered at 823 K. Mostly iron rich carbides are present in the steel subjected to tempering at low temperatures of around 723 K, whereas chromium rich carbides (M{sub 23}C{sub 6}) dominate precipitation at high temperature tempering. The range 773–823 K is the transition temperature range for the precipitates, with both Fe{sub 2}C and M{sub 23}C{sub 6} types of carbides coexisting in the material. The nucleation of Fe{sub 2}C within the martensite lath, during low temperature tempering, has a definite role in the embrittlement of this steel. Embrittlement is not observed at high temperature tempering because of precipitation of M{sub 23}C{sub 6} carbides, instead of Fe{sub 2}C, preferentially along the lath and prior austenite boundaries. Segregation of S and P, which is widely reported as one of the causes for temper embrittlement, could not be detected in the material even through Auger electron spectroscopy studies. - Highlights: • Tempering behaviour of AISI 410 steel is studied within 673–923 K temperature range. • Temperature regime of maximum embrittlement is identified as 773–848 K. • Results show that type of

  1. Wear properties of niobium carbide coatings performed by pack method on AISI 1040 steel

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Ugur [Sakarya University, Technical Education Faculty, Department of Metal Education, 54187 Sakarya (Turkey)]. E-mail: ugursen@sakarya.edu.tr

    2005-07-01

    A series of experiments was performed to evaluate tribological properties of niobium carbide coated AISI 1040 steel. In coating process, thermo-reactive diffusion treatment by pack method was performed at the temperatures of 800, 900 and 1000 deg. C for 1-4 h, respectively. Depending on coating process time and temperature, the thickness of niobium carbide layer formed on substrate ranged from 3.4{+-}0.5 to 12{+-}2 {mu}m. The hardness of niobium carbide layers on the steel sample is 1792 HV. The presence of carbides (e.g. NbC, Nb{sub 2}C) formed on the surface of coated AISI 1040 steel was confirmed by X-ray diffraction analysis. Dry wear tests for uncoated and coated AISI 1040 steel against AISI D2 steel were carried out on pin-on-disk configuration and at sliding speed range of 0.5, 1, 2 and 5 m/s, and under 15 N and 30 N loads. The results showed that the average coefficient of friction for coated and uncoated AISI 1040 steel were 0.3 and 0.5, respectively. The specific wear rates for uncoated and coated steel are 4.47x10{sup -5} mm{sup 3}/N.m to 4.29x10{sup -4} and 4.37x10{sup -7} to 3.55x10{sup -5} mm{sup 3}/N.m.

  2. Nitriding Process Characterization of Cold Worked AISI 304 and 316 Austenitic Stainless Steels

    Directory of Open Access Journals (Sweden)

    Waldemar Alfredo Monteiro

    2017-01-01

    Full Text Available The nitriding behavior of austenitic stainless steels (AISI 304 and 316 was studied by different cold work degree (0% (after heat treated, 10%, 20%, 30%, and 40% before nitride processing. The microstructure, layer thickness, hardness, and chemical microcomposition were evaluated employing optical microscopy, Vickers hardness, and scanning electron microscopy techniques (WDS microanalysis. The initial cold work (previous plastic deformations in both AISI 304 and 306 austenitic stainless steels does not show special influence in all applied nitriding kinetics (in layer thicknesses. The nitriding processes have formed two layers, one external layer formed by expanded austenite with high nitrogen content, followed by another thinner layer just below formed by expanded austenite with a high presence of carbon (back diffusion. An enhanced diffusion can be observed on AISI 304 steel comparing with AISI 316 steel (a nitrided layer thicker can be noticed in the AISI 304 steel. The mechanical strength of both steels after nitriding processes reveals significant hardness values, almost 1100 HV, on the nitrided layers.

  3. Plasma post oxidation of nitrocarburized AISI 4140 steel

    Institute of Scientific and Technical Information of China (English)

    LEE Insup

    2006-01-01

    Plasma nitrocarburizing and plasma oxidizing treatments were performed to improve the wear and corrosion resistance of AISI 4140 steel.Plasma nitrocarburizing was conducted for 3 h at 570 ℃ in the nitrogen, hydrogen and methane atmosphere to produce the ε-Fe2-3(N,C) phase.It was found that the compound layer produced by plasma nitrocarburising was predominantly composed of ε-phase, with a small proportion of γ'-Fe4(N,C) phase.The thickness of the compound layer was about 10 μm and the diffusion layer was about 300 μm in thickness, respectively.Plasma post oxidation was performed on the nitrocarburized samples with various oxygen/hydrogen ratio at a constant temperature of 500 ℃ for 1 h.The very thin magnetite (Fe3O4) layer 1-2 μm in thickness on top of the compound layer was obtained by plasma post oxidation.It was confirmed that the corrosion characteristics of the nitrocarburized compound layer can be further improved by the application of the superficial magnetite layer.

  4. AISI waste oxide recycling program. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Aukrust, E.; Downing, K.B.; Sarma, B.

    1995-08-01

    In March 1995 AISI completed a five-year, $60 million collaborative development program on Direct Steelmaking cost-shared by DOE under the Metals Initiative. This program defined an energy-efficient and environmentally-friendly technology to produce hot metal for steelmaking directly from coal and iron ore pellets without incurring the high capital costs and environmental problems associated with traditional coke oven and blast furnace technology. As it becomes necessary to replace present capacity, this new technology will be favored because of reduced capital costs, higher energy efficiency, and lower operating costs. In April 1994, having failed to move forward with a demonstration plant for direct ironmaking, despite substantial efforts by both Stelco and Geneva Steel, an alternative opportunity was sought to commercialize this new technology without waiting until existing ironmaking capacity needed to be replaced. Recycling and resource recovery of steel plant waste oxides was considered an attractive possibility. This led to approval of a ten-month, $8.3 million joint program with DOE on recycling steel plant waste oxides utilizing this new smelting technology. This highly successful trial program was completed in December 1994. The results of the pilot plant work and a feasibility study for a recycling demonstration plant are presented in this final technical report.

  5. Ferromagnetic properties of cold rolled AISI 304L steel

    Science.gov (United States)

    Tavares, S. S. M.; da Silva, M. R.; Neto, J. M.; Miraglia, S.; Fruchart, D.

    2002-04-01

    The ferromagnetic properties (coercive force, residual and saturation magnetisation) of a cold rolled AISI 304L stainless steel were measured as function of the applied deformation, using a vibrating sample magnetometer. The martensite volume fraction produced by deformation was calculated through the magnetisation saturation ( σs) value. A maximum amount of martensite (81%) was obtained by applying a true deformation ɛ=2.41 and a heat treatment at 400°C after rolling. The residual induction ( Br) and the squareness (=ratio between residual ( Br) and saturation ( Bs) inductions) increased, while the coercive field ( Hc) decreased with the amount of deformation. The heat treatment at 400°C promotes as well the increase of both Br and Br/ Bs and the decrease of Hc. The magnetic properties obtained in the most severely deformed samples ( Hc=23.08-23.63 kJ/m 3, Br=1.01-1.20 T and Bs=1.12-1.28 T) are comparable to that of some hard and semi-hard alloys used as magnets. The stability of the ferromagnetic martensite ( α') was investigated by thermomagnetic analysis. The starting ( As) and final ( Af) temperatures of the martensite phase ( α') transformation into austenite during heating were determined to As=430-440°C and Af=610-616°C.

  6. Estudio de impedancia de la corrosión del acero inoxidable AISI 316L en las regiones pasiva y de picadura

    Directory of Open Access Journals (Sweden)

    Polo Sanz, José Luis

    1999-12-01

    Full Text Available Impedance measurements were performed on an AISI 316L stainless steel immersed in a 5% NaCl solution at room temperature. Some samples were polarized up to the passive and pitting regions, respectively. The Nyquist plots in the rest potential and in the passive region show high impedance with capacitive behaviour. The impedance diagram in the pitting region shows three loops: a capacitive loop at high frequencies, a loop with inductive effects at intermediate frequencies, and a second capacitive response at low frequencies. To validate the impedance data Kramers-Kronig relations were applied in the pitting región.

    Se estudia la corrosión del acero inoxidable AISI 316L en solución de NaCl al 5% y a temperatura ambiente, utilizándose probetas polarizadas hasta las regiones pasiva y de picadura. Se obtuvieron diagramas de impedancia en el potencial de corrosión y en esas dos regiones. Los diagramas de impedancia en el potencial de corrosión y en la región pasiva muestran comportamiento capacitivo. En la región de picadura los diagramas de impedancia presentan tres bucles capacitivos: un bucle capacitivo a altas frecuencias, un bucle con efectos inductivos a frecuencias intermedias y un segundo bucle capacitivo a bajas frecuencias. Se aplicaron las transformadas de Kramers-Kronig a los resultados de impedancia obtenidos en la región de picadura.

  7. Evaluación del comportamiento estructural y de resistencia a la corrosión de armaduras de acero inoxidable austenítico AISI 304 y dúplex AISI 2304 embebidas en morteros de cemento Pórtland

    Directory of Open Access Journals (Sweden)

    Medina, E.

    2012-12-01

    Full Text Available The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304 and duplex EN 1.4362 (AISI 2304 have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR, of reinforcements embedded in ordinary Portland cement (OPC mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure.

    Se ha evaluado el comportamiento mecánico y estructural de dos aceros inoxidables corrugados, el austenítico EN 1.4301 (AISI 304 y el dúplex EN 1.4362 (AISI 2304, y se han comparado con el tradicional acero al carbono B500SD. El estudio se ha realizado en tres niveles: a nivel de barra, de sección y de pieza. Las diferentes características mecánicas de los aceros inoxidables condicionan el comportamiento a nivel de sección y de pieza estructural. El estudio del comportamiento frente a la corrosión de los dos aceros inoxidables se ha realizado mediante mediciones electroquímicas monitorizando el potencial de corrosión y la resistencia de polarización de armaduras embebidas en probetas de mortero contaminado con diferentes concentraciones de cloruros durante un tiempo de exposición de un año. Ambos aceros inoxidables permanecen en estado pasivo en las probetas para todos los contenidos de cloruros.

  8. The influence of cutting speed and feed rate in surface integrity of aisi 1045//Influencia de la velocidad de corte y la velocidad de avance en la integridad superficial del acero aisi 1045

    Directory of Open Access Journals (Sweden)

    Mario Jacas-Cabrera

    2015-09-01

    Full Text Available El objetivo de esta investigación es el estudio de la influencia de la velocidad de corte y la velocidad de avance en la integridad superficial del acero AISI-1045, sometido a un proceso de torneado. Las probetas se sometieron a un tratamiento térmico de recocidos (81 HRB. En el trabajo se empleó un diseño experimental 32, con dos variables a tres niveles experimentales, para un total de nueve experimentos, los que fueron replicados. La integridad superficial fue evaluada con la medición de la rugosidad superficial, las tensiones residuales superficiales, la medición de dureza por nano–indentación y por el análisis de la de formación terciaria. Los resultados determinaron la gran influencia de la velocidad de avance en la rugosidad superficial. La medición de las tensiones residuales mostró la influencia de las variables de corte. Del análisis microestructural se observó la existencia de dos zonas de deformación determinándose que el espesor de la zona endurecida llegó a 50 µm. Palabras claves: integridad superficial, rugosidad superficial, nano-indentación; superficie deformada____________________________________________________________________________AbstractThe aim of this research is to study the influence of cutting speed and feed rate on surface integrity of AISI-1045 subjected to a turning process. The specimens were in annealed condition (81 HRB. A 32 factorial experiment design was employed using low, medium and high levels of the two variables in study, performing 9 experiments with a replica. The surfaces were evaluated through the measurements of surface roughness, surface residual stresses, nano-indentation hardness and analyzing the deformed layer. Results corroborated the great influence of feed rate on surface roughness. The results of the residual stresses have shown the influence of cutting speed as well as feed rate in the behavior of circumferential and axial stress respectively. From the analysis of the

  9. Estudio del desgaste del flanco de carburos recubiertos y cermet durante el torneado de alta velocidad en seco del acero AISI 1045

    Directory of Open Access Journals (Sweden)

    Hernández-González, L. W.

    2011-06-01

    Full Text Available This work deals with the experimental study of the flank wear evolution of two coating carbide inserts and a cermet insert during the dry finishing turning of AISI 1045 steel with 400, 500 and 600 m/min cutting speeds. The results were analyzed using the variance analysis and lineal regression analysis in order to describe the relationship between the flank wear and machining time, obtaining the adjusted model equation. The investigation demonstrated a significant effect of cutting speed and machining time on the flank wear at high speed machining. The three coating layers insert showed the best performance while the two layers insert had the worst behaviour of the cutting tool wear at high cutting speeds.

    El objetivo de este trabajo es el estudio experimental de la evolución del desgaste del flanco respecto al tiempo de dos insertos de carburo recubiertos y un cermet durante el torneado de acabado en seco del acero AISI 1045 con velocidades de corte de 400, 500 y 600 m/min. Los resultados fueron comparados utilizando el análisis de varianza y el análisis de regresión lineal para describir la relación entre el desgaste del flanco y el tiempo de maquinado, obteniéndose la ecuación del modelo ajustado. La investigación demostró un efecto significativo de la velocidad de corte y del tiempo de maquinado en el desgaste del flanco en el maquinado de alta velocidad. El mejor desempeño se obtuvo para el carburo recubierto con tres capas, mientras que el carburo con dos capas sufrió el mayor desgaste a elevadas velocidades de corte.

  10. Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

    Science.gov (United States)

    Townsend, Dennis P.; Patel, P. R.

    1988-01-01

    Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

  11. EFFECTS OF COPPER ION IMPLANTATION ON ANTIBACTERIAL ACTIVITY OF AISI420 STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    Z.G. Dan; H.W. Ni; B.F. Xu; J. Xiong; P. Y. Xiong

    2005-01-01

    Antibacterial activity of AISI420 stainless steel (SS) implanted by copper was investigated. Ions extracted from a metal vapor vacuum arc (MEVVA) are sourced with 100keV energy and a dose range from 0.2×1017 to 2.0×1017ions .cm-2. The saturation dose of Cu implantation in AISI420 SS and Cu surface concentration were calculated at the energy of 100keV. The effect of dose on the antibacterial activity was analyzed. Results of antibacterial test show that the saturation dose is the optimum implantation dose for best antibacterial activity, which is above 99% against both Escherichia coli and Staphylococcus aureus. Novel phases such as Fe4Cu3 and Cu9.9Fe0.1 were found in the implanted layer by glancing angle X-ray diffraction (GXRD). The antibacterial activity of AISI420 SS attributes to Cu-contained phase.

  12. Diffusional Growth Kinetics Analisys of Fe2B Layers Applied During the Coating Powder-Pack Boriding Process on an AISI 1026 Steel

    Directory of Open Access Journals (Sweden)

    M. Elias-Espinosa

    2015-01-01

    Full Text Available La exigencia de emplear materiales con propiedades avanzadas incluyen la necesidad de aplicar recubrimientos de alta resistencia que alarguen la vida de útil de aceros comerciales, de esta forma, el tratamiento termoquímico de borurización tiene el potencial para cumplir estos requerimientos. En este trabajo de investigación se formula un modelo matemático para analizar la cinética de crecimiento de las capas de 2 Fe B formadas sobre la superficie de un acero AISI 1026. El modelo matemático propuesto se desarrolló en base a la solución de la ecuación de balance de masa de la interface de crecimiento 2 Fe B/Fe para evaluar el coeficiente de difusión del boro a través de las capas de Fe2B en un rango de temperaturas de 1123 a1273 K. En el modelo desarrollado se incluyó el tiempo de incubación del boruro para formar la fase Fe2B. El modelo matemático fue validado con datos experimentales realizados a una temperatura de 1253 K y tiempo de siete horas. Las capas de boruro fueron caracterizadas y analizadas por microscopia óptica y de barrido (se obtuvo un EDS, así como por Difracción de Rayos – X (XRD. Se utilizó la técnica de indentación Daimler-Benz Rockwell-C para evaluar cualitativamente la adherencia de la capa de Fe2B sobre el sustrato (acero AISI 1026. Para usos prácticos y para un espesor determinado, se propuso un diagrama a espesor constante (215 μm el cual es controlado con la variación de la temperatura y tiempo de exposición al recubrimiento. De los resultados obtenidos, se encontró que la energía de activación para el boro en el acero AISI 1026 es igual a 178 kJ mol-1.

  13. FLOW STRESS MODEL FOR HARD MACHINING OF AISI H13 WORK TOOL STEEL

    Institute of Scientific and Technical Information of China (English)

    H. Yan; J. Hua; R. Shivpuri

    2005-01-01

    An approach is presented to characterize the stress response of workpiece in hard machining,accounted for the effect of the initial workpiece hardness, temperature, strain and strain rate on flow stress. AISI H13 work tool steel was chosen to verify this methodology. The proposed flow stress model demonstrates a good agreement with data collected from published experiments.Therefore, the proposed model can be used to predict the corresponding flow stress-strain response of AISI H13 work tool steel with variation of the initial workpiece hardness in hard machining.

  14. Activated flux tungsten inert gas welding of 8 mm-thick AISI 304 austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    刘观辉; 刘美华; 易耀勇; 张宇鹏; 罗子艺; 许磊

    2015-01-01

    AISI 304 stainless steel plates were welded with activated flux tungsten inert gas (A-TIG) method by utilizing self-developed activated flux. It is indicated from the experimental results that for 8 mm-thick AISI 304 stainless steel plate, weld joint of full penetration and one-side welding with good weld appearance can be obtained in a single pass without groove preparation by utilizing A-TIG welding. Moreover, activated flux powders do not cause significant effect on the microstructure of TIG weld and the mechanical properties of A-TIG weld joints are also superior to those of C-TIG (conventional TIG) welding.

  15. Development of Flow Stress of AISI H13 Die Steel in Hard Machining

    Institute of Scientific and Technical Information of China (English)

    YAN Hong; QIAN Guohua; HU Qiang

    2007-01-01

    An approach was presented to characterize the stress response of workpiece in hard machining, accounting for the effect of the initial workpiece hardness in addition to temperature, strain and strain rate on flow stress in this paper. AISI H13 die steel was chosen to verify this methodology. The proposed flow stress model demonstrates a good agreement with experimental data. Therefore, the proposed model can be used to predict the corresponding flow stress-strain response of AISI H13 die steel with variation of the initial workpiece hardness in hard machining.

  16. Biomaterial Studies on AISI 316L Stainless Steel after Magnetoelectropolishing

    Directory of Open Access Journals (Sweden)

    Massimiliano Filippi

    2009-03-01

    Full Text Available The polarisation characteristics of the electropolishing process in a magnetic field (MEP – magnetoelectropolishing, in comparison with those obtained under standard/conventional process (EP conditions, have been obtained. The occurrence of an EP plateau has been observed in view of the optimization of MEP process. Up-to-date stainless steel surface studies always indicated some amount of free-metal atoms apart from the detected oxides and hydroxides. Such a morphology of the surface film usually affects the thermodynamic stability and corrosion resistance of surface oxide layer and is one of the most important features of stainless steels. With this new MEP process we can improve metal surface properties by making the stainless steel more resistant to halides encountered in a variety of environments. Furthermore, in this paper the stainless steel surface film study results have been presented. The results of the corrosion research carried out by the authors on the behaviour of the most commonly used material - medical grade AISI 316L stainless steel both in Ringer’s body fluid and in aqueous 3% NaCl solution have been investigated and presented earlier elsewhere, though some of these results, concerning the EIS Nyquist plots and polarization curves are also revealed herein. In this paper an attempt to explain this peculiar performance of 316L stainless steel has been undertaken. The SEM studies, Auger electron spectroscopy (AES and X-ray photoelectron spectroscopy (XPS were performed on 316L samples after three treatments: MP – abrasive polishing (800 grit size, EP – conventional electrolytic polishing, and MEP – magnetoelectropolishing. It has been found that the proposed magnetoelectropolishing (MEP process considerably modifies the morphology and the composition of the surface film, thus leading to improved corrosion resistance of the studied 316L SS.

  17. The adhesion of hot-filament CVD diamond films on AISI type 316 austenitic stainless steel

    NARCIS (Netherlands)

    Buijnsters, J.G.; Shankar, P.; Enckevort, W.J.P. van; Schermer, J.J.; Meulen, J.J. ter

    2004-01-01

    Steel ball indentation and scratch adhesion testing of hot filament chemical vapour deposited diamond films onto AISI type 316 austenitic stainless steel substrates using two different interlayer systems, namely chromium nitride and borided steel, have been investigated. In order to compare the adhe

  18. Micro-structural strengthening mechanism of multiple laser shock processing impacts on AISI 8620 steel

    Energy Technology Data Exchange (ETDEWEB)

    Lu, J.Z. [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China); Zhong, J.W., E-mail: zjw1033@126.com [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China); Luo, K.Y.; Zhang, L.; Dai, F.Z. [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China); Chen, K.M. [School of Materials Science and Engineering, Jiangsu University, Zhenjiang 212013 (China); Wang, Q.W.; Zhong, J.S.; Zhang, Y.K. [School of Mechanical Engineering, Jiangsu University, Xuefu Road 301, Jingkou District, Zhenjiang 212013 (China)

    2011-07-25

    Highlights: {yields} LSP can clearly refine coarse grains in the shocked region by dislocation movement. {yields} Micro-structural evolution of AISI 8620 steel after LSP impacts is revealed. {yields} LSP on AISI 8620 steel have grain refinement and dispersion strengthening of carbon. {yields} The results can provide some insights on surface modification of low carbon steel. - Abstract: Micro-structural evolution in the near-surface region of AISI 8620 steel subjected to multiple laser shock processing (LSP) impacts were investigated by means of cross-sectional optical microscopy (OM) and transmission electron microscopy (TEM) observations. Micro-structural evolution process subjected to multiple LSP impacts can be described as follows: (i) the parallel lamellar pearlites are broken into bitty pearlites, and dislocation activities simultaneously led to the formation of dislocation lines (DLs) and dislocation pile-ups in original grains; (ii) bitty pearlites were all broken into Fe{sub 3}C granules, and dislocation movement made Fe{sub 3}C granules disperse near subgrain boundaries and led to subgrain boundaries separating individual cells, and (iii) subgrain boundaries were refined to grain boundaries. Multiple LSP impacts on AISI 8620 steel had dual-function: the refinement of coarse grains in the near-surface region by dislocation movement and dispersion strengthening of C atoms which cut cementite and diffused into the ferrite by moving dislocations.

  19. Influence of temperature on AISI 316L corrosion in phosphoric acid solutions under hydrodynamic conditions

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Tovar, R.; Montanes, M.T.; Garcia-Anton, J. [Valencia Univ. Politecnica, Dept. de Ingenieria Quimica y Nuclear. ETSI Industriales, Valencia (Spain); Ben Bachir, A.; Abdelkebir, B.; Elmandoubi, N. [University Mohammed V-Agdal, Lab. Corrosion-Electrochimie, Faculty of Sciences, Rabat (Morocco)

    2009-07-01

    AISI 316L stainless steel, due to its good mechanical properties and corrosion resistance, is widely used in the phosphoric acid industry, including piping lines. However, phosphoric acid (H{sub 3}PO{sub 4}) is a medium-strong acid, and corrosion problems could occur, especially working with concentrated solutions and increasing temperature. Furthermore, fluid flow can increase corrosion rates. The objective of this work is to study the dynamic corrosion of AISI 316L stainless steel in a range of temperature from 25 C to 60 C by means of cyclic potentiodynamic curves. A hydrodynamic circuit was used in order to study dynamic corrosion. The experiments were carried out in an oxygen-free environment at different Reynolds numbers: 1,456, 3,166 and 5,066. The results show that uniform corrosion mechanisms can be expected for AISI 316L stainless steel in 5.5 M H{sub 3}PO{sub 4} solutions, since no hysteresis loop was observed. Moreover, temperature affects the corrosion parameters obtained from the polarization curves. Temperature shifts corrosion potential to nobler values, reduces the passivity region and enhances passivation current density. On the other hand, little influence of Reynolds number was observed on AISI 316L stainless steel corrosion. (authors)

  20. Efecto del volumen de metal cortado y de la velocidad de corte en el desgaste de la herramienta durante el torneado de alta velocidad del acero AISI 1045

    Directory of Open Access Journals (Sweden)

    Luis W. Hernández González

    2011-01-01

    Full Text Available En este trabajo se aborda el estudio experimental del efecto del volumen de metal cortado y de la velocidad de corte en el desgaste del flanco de dos insertos de carburos recubiertos y un cermet, durante el torneado de acabado en seco del acero AISI 1045 a velocidades de corte moderada, intermedia y alta. Los resultados fueron comparados utilizando la dimensión volumétrica de la vida útil de la herramienta, el análisis de varianza y el análisis de regresión lineal para describir la relación entre el desgaste y el volumen removido, según las ecuaciones del modelo ajustado. La investigación mostró un efecto significativo de la velocidad de corte y del volumen cortado en el desgaste del flanco, pues se logró el mejor desempeño para la alta velocidad con el carburo recubierto con tres capas y el peor funcionamiento con el carburo recubierto con dos capas.

  1. Resistência à corrosão de junta dissimilar soldada pelo processo TIG composta pelos aços inoxidáveis AISI 316L e AISI 444

    Directory of Open Access Journals (Sweden)

    Luis Henrique Guilherme

    2014-03-01

    Full Text Available O aço inoxidável AISI 444 tornou-se uma opção para substituir a liga AISI 316L devido ao seu menor custo e satisfatória resistência à corrosão. Entretanto, o uso da liga AISI 444 no feixe tubular de trocadores de calor acarreta na soldagem de uma junta dissimilar. O presente estudo teve por objetivo avaliar a resistência à corrosão da junta tubo-espelho soldada pelo processo TIG composta pelas ligas AISI 316L e AISI 444. A manufatura das amostras consistiu em replicar o projeto da junta tubo-espelho de trocadores de calor. Realizou-se em juntas soldadas ensaios de sensitização, perda de massa por imersão desde a temperatura ambiente até 90 ºC, e ensaios eletroquímicos de polarização potenciodinâmica nos eletrólitos 0,5 mol/L de HCl e 0,5 mol/L de H2SO4. Os resultados mostraram que a junta dissimilar sofreu corrosão galvânica com maior degradação na zona afetada pelo calor (ZAC do tubo AISI 444. Porém, os mecanismos de corrosão localizada (pite e intergranular demonstraram ser mais ativos para a liga AISI 316L. Conclui-se que a junta dissimilar apresentou melhor resistência à corrosão do que a junta soldada composta unicamente pela liga AISI 316L em temperaturas de até 70 ºC, conforme as condições observadas neste trabalho.

  2. Effect of heat treatment on an AISI 304 austenitic stainless steel evaluated by the ultrasonic attenuation coefficient

    Energy Technology Data Exchange (ETDEWEB)

    Moghanizadeh, Abbas; Farzi, Abolfazl [Islamic Azad Univ., Esfarayen (Iran, Islamic Republic of). Dept. of Civil Engineering

    2016-07-01

    The properties of metals can be substantially changed by various methods, one of them is using heat treatment processes. Moreover, ultrasonic testing is the most preferred and effective, nondestructive testing technique for characterization of mechanical material properties. Austenitic stainless steel AISI 304 serves in many applications due to high strength and corrosion resistance. In certain applications, it is important to evaluate the mechanical properties of AISI 304 stainless steel. In this study, the ultrasonic method (attenuation measurement technique) is used to evaluate the hardness of AISI 304 stainless steel samples which were heat treated at different levels. Due to the heat treatment process, each sample has its specific microstructure and hardness which attenuate ultrasonic waves appropriately. The ultrasonic and hardness test show that it is possible to evaluate the hardness of AISI 304 stainless steel by ultrasonic attenuation coefficient. In addition, the relationship between ultrasonic attenuation coefficients and time of heat treatment is investigated.

  3. Análisis de soldabilidad de aceros inoxidables con aceros de medio y bajo carbono por SMAW

    Directory of Open Access Journals (Sweden)

    José Luddey Marulanda Arevalo

    2013-12-01

    Full Text Available Se presenta un estudio de la soldabilidad de aceros inoxidables austeníticos AISI 304 y AISI 316 con aceros de bajo y medio carbono AISI 1020 – AISI 1045, empleando como materiales de aporte los electrodos EutecTrode® 52 NG, 54 NG y 57 NG, mediante el proceso de arco eléctrico con electrodo revestido (SMAW. Para analizar la soldabilidad de estos electrodos cuando se realiza la unión de aceros inoxidables con aceros al carbono, se practicaron pruebas metalográficas y ensayos mecánicos de dureza, doblez y tracción, con el fin de observar el comportamiento tanto de la zona afectada térmicamente como del cordón de soldadura, a partir del cambio en las propiedades mecánicas y metalúrgicas en las diferentes regiones de las uniones soldadas. Durante el proceso de soldadura se siguió una especificación del procedimiento de soldadura (WPS, para que los resultados fueran repetibles, minimizando los problemas de agrietamiento en caliente, agrietamiento en frío, formación de fase sigma y precipitación de carburos.

  4. RESISTENCIA A LA CORROSIÓN DE LAS MULTICAPAS DE [TIN/ALTIN]n DEPOSITADAS SOBRE ACERO AL CARBONO AISI 1045

    Directory of Open Access Journals (Sweden)

    WILLIAM APERADOR

    2011-01-01

    Full Text Available En este artículo se presenta el mejoramiento frente a la corrosión de los recubrimientos multicapas de [TiN/AlTiN]n con periodos de 2, 6, 12 y 24 bicapas depositados mediante la técnica de PVD magnetrón Sputtering sobre acero al carbono AISI 1045. La evaluación electroquímica se realizó mediante las técnicas espectroscopia de impedancia electroquímica (EIS y curvas de polarización Tafel, en una solución de 0.5M de H2SO4 + 3.5% wt. de NaCl. La resistencia a la corrosión aumentó de forma gradual en función del número de bicapas en comparación al sustrato encontrando valores de velocidad de corrosión de 18.51 mpy para el sustrato sin recubrir y de 1x10 6 mpy para la muestra con 24 bicapas. Los resultados electroquímicos revelan el efecto positivo en cuanto a la protección superficial del acero 1045 con el incremento del periodo en las multicapas de [TiN /AlTiN]n.

  5. Caracterización mediante HRTEM de un acero AISI4140 nitrurado por postdescarga micro-ondas

    Directory of Open Access Journals (Sweden)

    Béjar-Gómez, L.

    2005-12-01

    Full Text Available An analysis of the nitrides formed in an AISI 4140 steel nitrided by postdischarge microwave nitriding treatment was carried out by high resolution transmission electron microscopy (HRTEM, fast Fourier transform (FFT and nanoanalysis. The steel samples were nitrided below of the eutectoid transformation point (590 °C, after nitriding the samples were cooling slowly inside in the reactor whit an argon atmosphere. The analysis were carried out in a FEG-TEM PHILIPS TECNAI F20 at 200 Kv. The results showed the morphology and size of the nitrides ε-Fe2-3N and γ’-Fe4N, which had coherency whit the matrix. By other hand the following crystallographic relations were determined: (110 Fe-α ║ (1001 ε-Fe2-3N ║ (110 γ’-Fe4N and [1-1 0]Fe-α ║ [1 0-1 0] ε-Fe2-3N ║ [0 1 1] Fe4N.

    Un análisis de las fases de nitruros formados en un acero AISI 4140, nitrurado mediante condiciones de postdescarga micro-ondas, se llevó a cabo por microscopía electrónica de transmisión de alta resolución (HRTEM, rápida transformada de Fourier (FFT y nanoanálisis. Las muestras de acero fueron nitruradas por debajo del punto de transformación eutectoide (590 °C; después del tratamiento de nitruración las piezas fueron enfriadas lentamente dentro del reactor con una atmósfera de argón. Los análisis se realizaron en un microscopio Philips con cañón de emisión de campo Tecnai F20 a 200 Kv (PHILIPS FEG-TEM TECNAI F20. Los resultados mostraron la morfología y tamaño de los nitruros de hierro ε-Fe2-3N y γ’-Fe4N, los cuáles mostraron coherencia con la matriz. Además, se obtuvo la siguiente relación de coherencia entre precipitados y matriz: (110 Fe-α ║ (1001 ε-Fe2-3N ║ (110 γ’-Fe4N y [1-1 0]Fe-α ║ [1 0-1 0] ε-Fe2-3N ║ [0 1 1] Fe4N.

  6. Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100. Part 1. Experimental Results (Preprint)

    Science.gov (United States)

    2009-10-01

    factors to the L-P life model are currently used as standard practice to account for improvements in bearing material cleanliness and processing...eleven 12.7 mm diameter ABMA Grade 10 silicon nitride (Si3N4) balls, Ra finish of 6.4 nm and one piece machined silver plated AISI 4340 steel cages...piloted on both sides of the outer ring. The outer ring cage- land shoulders of the M50NiL bearings were titanium nitride (TiN) coated per aerospace

  7. Control of critical parameters for square cup deep drawing of AISI 304 DDQ using genetic algorithm//Control de parámetros críticos en la embutición de una copa rectangular de AISI 304 DDQ empleando algoritmo genético

    Directory of Open Access Journals (Sweden)

    Yudieski Bernal-Aguilar

    2013-05-01

    Full Text Available AbstractsThe main purpose of this work is to develop an intellectualized control technique on the deep drawing of square cup made of AISI 304 DDQ stainless steel using genetic algorithm. These control methods are employed in order to investigate the most significant parameters in sheet metal forming process such as drawing force, with a view of optimizing these parameters. The genetic algorithm is used for theoptimization purpose to minimize the force of the deep drawing process and to investigate the roles of other parameters as blank holder force. Experimental results show that these combinations of control system can cover a wide range of both materials and influential forming parameters automatically. The results further confirm that the developed system is effective and valid alternative for quick responsible control system with high flexibility.Key words: intelligent control, deep drawing, genetic algorithm, sheet metal forming._______________________________________________________________________________ResumenEl objetivo principal del trabajo es desarrollar un método  de control inteligente para la embutición de una pieza rectangular fabricada en AISI DDQ empleando algoritmo genético. Este método de control se utiliza para investigar parámetros críticos en el proceso de conformado de chapa metálica, tales como la fuerza en el prensachapas y  la fuerza máxima de embutición, con el fin de minimizar este parámetro. Los resultados experimentales obtenidos demuestran que el método de control puede cubrir un amplio espectro de combinaciones, tanto para los materiales, como para los parámetros críticos y es una técnica alternativa y flexible, válida para desarrollar sistemas de control en los procesos de embutición con gran flexibilidad. Palabras claves: control inteligente, embutición profunda, algoritmo genético, conformado de chapa metálica

  8. Estudio de los tipos de cráteres obtenidos en el impacto de proyectiles 5,56 SS109, sobre blancos de acero AISI-SAE 1045

    Directory of Open Access Journals (Sweden)

    Castro, Álvaro

    2000-02-01

    Full Text Available The present work describes the morphology and formation of the types of craters obtained with the impact of projectiles 5,56 SS109 over seven steel plates AISI-SAE 1045 that received different cycles of heat treatment. A comparison between the type of deformation and fracture structures and the ones generated by the impact of this projectile over one steel armor plate was made. Each one of the craters was characterized by visual and metallography observation. The influence of the plate microstructure on the efficiency for stopping the projectile and the mechanism of craters formation was evaluated.

    En el presente trabajo se describe la morfología y formación de los tipos de cráteres obtenidos, en el impacto de proyectiles 5,56 SS109, sobre siete chapas de acero AISI-SAE 1045 que fueron sometidas a diferentes tratamientos térmicos, comparando el tipo de estructuras de deformación y fractura obtenidas con las formadas por el impacto de uno de estos proyectiles sobre una chapa comercial para blindaje. Cada uno de los cráteres se caracterizó mediante ensayos de inspección visual y metalografía evaluándose, a partir de los resultados, el papel que ejerce la microestructura obtenida sobre el nivel de eficiencia en la detención del proyectil por parte de la chapa y el mecanismo de formación de los cráteres.

  9. Oxidation behavior of 26Cr-16Ni and AISI 309 austenitic stainless steels in air flow at 1,173 K

    Energy Technology Data Exchange (ETDEWEB)

    Pipatnukun, Peeraya; Wangyao, Panyawat; Lothongkum, Gobboon [Chulalongkorn Univ., Bangkok (Thailand). Dept. of Metallurgical Engineering

    2015-11-01

    This work investigates the isothermal oxidation behavior of as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 at 1,173 K in air flow rate of 40 cm{sup 3} x min{sup -1} using thermogravimetric analysis (TGA). In 33 hours, the oxidation resistance declines from high to low are as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309, respectively. The oxidation kinetic results show that the exponential rate constant of the as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 are 8.79 x 10{sup -6}, 4.02 x 10{sup -5} and 4.35 x 10{sup -5} g x cm{sup -2} x s{sup -n}, respectively. The exponential growth rates of as cast 26Cr-16Ni, as cold-rolled AISI 309 and as cast AISI 309 are 0.42, 0.29 and 0.32, respectively. It indicates that the oxidation kinetic of as cast 26Cr-16Ni approaches a parabolic rate law, but those of as cold-rolled and as cast AISI 309 approach the cubic rate law. The sequence of oxide scale formations on the tested samples is also discussed.

  10. Evaluation of structural behaviour and corrosion resistant of austenitic AISI 304 and duplex AISI 2304 stainless steel reinforcements embedded in ordinary Portland cement mortars; Evaluacion del comportamiento estructural y de resistencia a la corrosion de armaduras de acero inoxidable austenitico AISI 304 y duplex AISI 2304 embebidas en morteros de cemento Portland

    Energy Technology Data Exchange (ETDEWEB)

    Medina, E.; Cobo, A.; Bastidas, D. M.

    2012-07-01

    The mechanical and structural behaviour of two stainless steels reinforcements, with grades austenitic EN 1.4301 (AISI 304) and duplex EN 1.4362 (AISI 2304) have been studied, and compared with the conventional carbon steel B500SD rebar. The study was conducted at three levels: at rebar level, at section level and at structural element level. The different mechanical properties of stainless steel directly influence the behaviour at section level and structural element level. The study of the corrosion behaviour of the two stainless steels has been performed by electrochemical measurements, monitoring the corrosion potential and the lineal polarization resistance (LPR), of reinforcements embedded in ordinary Portland cement (OPC) mortar specimens contaminated with different amount of chloride over one year time exposure. Both stainless steels specimens embedded in OPC mortar remain in the passive state for all the chloride concentration range studied after one year exposure. (Author) 26 refs.

  11. Finite Element Simulation and Experimental Verification of Internal Stress of Quenched AISI 4140 Cylinders

    Science.gov (United States)

    Liu, Yu; Qin, Shengwei; Hao, Qingguo; Chen, Nailu; Zuo, Xunwei; Rong, Yonghua

    2017-03-01

    The study of internal stress in quenched AISI 4140 medium carbon steel is of importance in engineering. In this work, the finite element simulation (FES) was employed to predict the distribution of internal stress in quenched AISI 4140 cylinders with two sizes of diameter based on exponent-modified (Ex-Modified) normalized function. The results indicate that the FES based on Ex-Modified normalized function proposed is better consistent with X-ray diffraction measurements of the stress distribution than FES based on normalized function proposed by Abrassart, Desalos and Leblond, respectively, which is attributed that Ex-Modified normalized function better describes transformation plasticity. Effect of temperature distribution on the phase formation, the origin of residual stress distribution and effect of transformation plasticity function on the residual stress distribution were further discussed.

  12. Finite Element Simulation and Experimental Verification of Internal Stress of Quenched AISI 4140 Cylinders

    Science.gov (United States)

    Liu, Yu; Qin, Shengwei; Hao, Qingguo; Chen, Nailu; Zuo, Xunwei; Rong, Yonghua

    2017-01-01

    The study of internal stress in quenched AISI 4140 medium carbon steel is of importance in engineering. In this work, the finite element simulation (FES) was employed to predict the distribution of internal stress in quenched AISI 4140 cylinders with two sizes of diameter based on exponent-modified (Ex-Modified) normalized function. The results indicate that the FES based on Ex-Modified normalized function proposed is better consistent with X-ray diffraction measurements of the stress distribution than FES based on normalized function proposed by Abrassart, Desalos and Leblond, respectively, which is attributed that Ex-Modified normalized function better describes transformation plasticity. Effect of temperature distribution on the phase formation, the origin of residual stress distribution and effect of transformation plasticity function on the residual stress distribution were further discussed.

  13. Sub-surface Fatigue Crack Growth at Alumina Inclusions in AISI 52100 Roller Bearings

    DEFF Research Database (Denmark)

    Cerullo, Michele

    2014-01-01

    Sub-surface fatigue crack growth at non metallic inclusions is studied in AISI 52100 bearing steel under typical rolling contact loads. A first 2D plane strain finite element analysis is carried out to compute the stress history in the innner race at a characteristic depth, where the Dang Van...... damage factor is highest. Subsequently the stress history is imposed as boundary conditions in a periodic unit cell model, where an alumina inclusion is embedded in a AISI 52100 matrix. Cracks are assumed to grow radially from the inclusion under cyclic loading. The growth is predicted by means...... of irreversible fatigue cohesive elements. Different orientations of the cracks and different matrix-inclusion bonding conditions are analyzed and compared....

  14. Behavior of AISI SAE 1020 Steel Implanted by Titanium and Exposed to Bacteria Sulphate Deoxidizer

    Science.gov (United States)

    Niño, Ely Dannier V.; Garnica, Hernán; Dugar-Zhabon, Veleriy; Castillo, Genis

    2014-05-01

    A hybrid technology to treat solid surfaces with the pulse high voltage and electric arc discharges of low pressure with a three-dimensional ion implantation technique (3DII) is applied. This technology is used to protect AISI SAE 1020 steel against a microbiological corrosion. The titanium ion implanted steel samples (coupons) are subjected to a medium of bacteria sulphate deoxidizer (BSD) which are very typical of the hydrocarbon industry and are potentially harmful for structures when are in contact with petroleum and some of its derivatives. The used technology aims to find an effective hybrid procedure to minimize the harmful effects of bacteria on AISI SAE 1020 steel. The hybrid technology efficiency of superficial titanium implantation is estimated through the measurements of the point corrosion characteristics obtained after testing both the treated and non-treated coupons. The three-dimensional surface structures of the samples are reconstructed with help of a confocal microscope.

  15. Study of carbonitriding thermochemical treatment by plasma screen in active with pressures main austenitic stainless steels AISI 409 and AISI 316L; Estudo do tratamento termoquimico de carbonitretacao por plasma em tela ativa com pressoes variaveis nos acos inoxidaveis austenitico AISI 316L e ferririco AISI 409

    Energy Technology Data Exchange (ETDEWEB)

    Melo, M.S.; Oliveira, A.M.; Leal, V.S.; Sousa, R.R.M. de; Alves Junior, C. [Centro Federal de Educacao Tecnologica do Maranhao (CEFET/MA), Sao Luis, MA (Brazil); Centro Federal de Educacao Tecnologica do Piaui (CEFET/PI), Teresina, PI (Brazil); Universidade Federal do Rio Grande do Norte (DF/UFRN), Natal, RN (Brazil). Dept. de Fisica. Labplasma

    2010-07-01

    The technique called Active Screen Plasma Nitriding (ASPN) is being used as an alternative once it offers several advantages with respect to conventional DC plasma. In this method, the plasma does not form directly in the sample's surface but on a screen, in such a way that undesired effects such as the edge effect is minimized. Stainless steels present not very satisfactory wearing characteristics. However, plasma carbonitriding has been used as to improve its resistance to wearing due to the formation of a fine surface layer with good properties. In this work, samples of stainless steel AISI 316L and AISI 409 were treated at pressures of 2.5 and 5 mbar. After the treatments they were characterized by microhardness, microscopy and Xray diffraction. Microscopy and hardness analysis showed satisfactory layers and toughness in those steels. (author)

  16. Corrosion resistance of the welded AISI 316L after various surface treatments

    Directory of Open Access Journals (Sweden)

    Tatiana Liptáková

    2014-01-01

    Full Text Available The main aim of this work is to monitor the surface treatment impact on the corrosion resistance of the welded stainless steel AISI 316L to local corrosion forms. The excellent corrosion resistance of austenitic stainless steel is caused by the existence of stable, thin and well adhering passive layer which quality is strongly influenced by welding. Therefore surface treatment of stainless steel is very important with regard to its local corrosion susceptibility Surfaces of welded stainless steel were treated by various mechanical methods (grinding, garnet blasting. Surface properties were studied by SEM, corrosion resistance was evaluated after exposition tests in chlorides environment using weight and metalographic analysis. The experimental outcomes confirmed that the mechanical finishing has a significant effect on the corrosion behavior of welded stainless steel AISI 316L.

  17. Experimental study of mechanical properties of friction welded AISI 1021 steels

    Indian Academy of Sciences (India)

    Amit Handa; Vikas Chawla

    2013-12-01

    Friction welding is widely used as a mass production method in various industries. In the present study, an experimental set-up was designed in order to achieve friction welding of plastically deformed AISI 1021 steels. In this study, low alloy steel (AISI 1021) was welded under different welding parameters and afterwards the mechanical properties such as tensile strength, impact strength and hardness were experimentally determined. On the basis of the results obtained from the experimentation, the graphs were plotted. It is the strength of welded joints, which is fundamental property to the service reliability of the weldments and hence present work was undertaken to study the influence of axial pressure and rotational speed in friction welded joints. Axial pressure and rotational speed are the two major parameters which can influence the strength and hence the mechanical properties of the friction welded joints. Thus the axial pressure and rotational speed were taken as welding parameters, which reflect the mechanical properties.

  18. In Situ Observation of Solidification Process of AISI 304 Austenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    HUANG Fu-xiang; WANG Xin-hua; ZHANG Jiong-ming; JI Chen-xi; FANG Yuan; YU Yan

    2008-01-01

    The solidification process of AISI 304 stainless steel during cooling at a rate of 0.05 K/s has been observed in situ using a confocal scanning laser microscope(CSLM).The results show that the δ phase appeared first in liquid steel,as the temperature decreased,the γ phase precipitated prior at δ-grain boundary at 1452.2℃,the liquid steel disappeared at 1431.3℃,and then theγphase precipitated on the δ ferrite.Based on the Scheil-GulliVer solidification model,the solidification processes of AISI 304 stainless steel are simulated using the Scheil model in Thermo-Calc.and the simulation results agree well with the results observed in the experiment.

  19. Martensitic Transformation in Ultrafine-Grained Stainless Steel AISI 304L Under Monotonic and Cyclic Loading

    Directory of Open Access Journals (Sweden)

    Heinz Werner Höppel

    2012-02-01

    Full Text Available The monotonic and cyclic deformation behavior of ultrafine-grained metastable austenitic steel AISI 304L, produced by severe plastic deformation, was investigated. Under monotonic loading, the martensitic phase transformation in the ultrafine-grained state is strongly favored. Under cyclic loading, the martensitic transformation behavior is similar to the coarse-grained condition, but the cyclic stress response is three times larger for the ultrafine-grained condition.

  20. Welding of AA1050 aluminum with AISI 304 stainless steel by rotary friction welding process

    OpenAIRE

    Chen Ying An; Francisco Piorino Neto; Eder Paduan Alves

    2010-01-01

    The purpose of this work was to assess the development of solid state joints of dissimilar material AA1050 aluminum and AISI 304 stainless steel, which can be used in pipes of tanks of liquid propellants and other components of the Satellite Launch Vehicle. The joints were obtained by rotary friction welding process (RFW), which combines the heat generated from friction between two surfaces and plastic deformation. Tests were conducted with different welding process parameters. The results we...

  1. Martensitic transformation during fatigue testing of an AISI 301LN steel

    OpenAIRE

    Mateo García, Antonio Manuel; Fargas Ribas, Gemma

    2012-01-01

    The plastic deformation accumulated during fatigue testing can induce the transformation of austenite to martensite in metastable austenitic stainless steels. To analyze this issue, a metastable austenitic stainless steel grade AISI 301 LN was studied in two different conditions, i.e. annealed and cold rolled. In the first case, the steel was fully austenitic, whereas cold rolled material had almost 30% of martensite. High cycle fatigue tests at a stress ratio of 0.8 were carried out on flat ...

  2. Cathodic cage nitriding of AISI 409 ferritic stainless steel with the addition of CH4

    Directory of Open Access Journals (Sweden)

    Rômulo Ribeiro Magalhães de Sousa

    2012-04-01

    Full Text Available AISI 409 ferritic stainless steel samples were nitrided using the cathodic cage plasma nitriding technique (CCPN, with the addition of methane to reduce chromium precipitation, increase hardness and wear resistance and reduce the presence of nitrides when compared to plasma carbonitriding. Microhardness profiles and X-Ray analysis confirm the formation of a very hard layer containing mainly ε-Fe3N and expanded ferrite phases.

  3. Friction welding of AA6061 to AISI 4340 using silver interlayer

    OpenAIRE

    Suresh D. Meshram; G. Madhusudhan Reddy

    2015-01-01

    The present work pertains to the study on joining of AA6061 and AISI 4340 through continuous drive friction welding. The welds were evaluated by metallographic examination, X-ray diffraction, electron probe microanalysis, tensile test and microhardness. The study reveals that the presence of an intermetallic compound layer at the bonded interface exhibits poor tensile strength and elongation. Mg in AA6061 near to the interface is found to be favourable for the formation and growth of Fe2Al5 i...

  4. Stoichiometric titanium dioxide ion implantation in AISI 304 stainless steel for corrosion protection

    Science.gov (United States)

    Hartwig, A.; Decker, M.; Klein, O.; Karl, H.

    2015-12-01

    The aim of this study is to evaluate the applicability of highly chemically inert titanium dioxide synthesized by ion beam implantation for corrosion protection of AISI 304 stainless steel in sodium chloride solution. More specifically, the prevention of galvanic corrosion between carbon-fiber reinforced plastic (CFRP) and AISI 304 was investigated. Corrosion performance of TiO2 implanted AISI 304 - examined for different implantation and annealing parameters - is strongly influenced by implantation fluence. Experimental results show that a fluence of 5 × 1016 cm-2 (Ti+) and 1 × 1017 cm-2 (O+) is sufficient to prevent pitting corrosion significantly, while galvanic corrosion with CFRP can already be noticeably reduced by an implantation fluence of 5 × 1015 cm-2 (Ti+) and 1 × 1016 cm-2 (O+). Surface roughness, implantation energy and annealing at 200 °C and 400 °C show only little influence on the corrosion behavior. TEM analysis indicates the existence of stoichiometric TiO2 inside the steel matrix for medium fluences and the formation of a separated metal oxide layer for high fluences.

  5. Application of direct laser metal tooling for AISI H13 tool steel

    Institute of Scientific and Technical Information of China (English)

    Jae-Ho LEE; Jeong-Hwan JANG; Byeong-Don JOO; Hong-Sup YIM; Young-Hoon MOON

    2009-01-01

    In the die industry, it is commonly agreed that residual tool life can be successfully extended by timely repair of damaged surfaces. Traditionally, the main repair process is tungsten inert gas (TIG) welding, but a new process called direct laser metal tooling (DLMT) emerges. DLMT is a manual process, of which results depend on the materials of the powders and tools, the laser process and parameters. This technology is a direct-metal freeform fabrication technique in which a 200 W fiber laser is used. AISI H13 tool steel is a suitable material for die casting tools because of the high resistance to thermal fatigue and dimensional stability. In this research, AISI HI3 tool steel was melted with metal powder by fiber laser. Before melting AISI H13, the powders were analyzed with XRF equipment. Then, hardness distribution of laser melted zone was investigated. The microstructure in laser melted zone was discussed. In order to identify the effect of particle size of powder on the melted zone, two types of particle sizes of powders were used. Experimental results show that the mold repair process using DLMT can be applied in the mold repair industry.

  6. Nanoscale precipitates and comprehensive strengthening mechanism in AISI H13 steel

    Science.gov (United States)

    Mao, Wen-wen; Ning, An-gang; Guo, Han-jie

    2016-09-01

    The effects of heat treatment on the precipitates and strengthening mechanism in AISI H13 steel were investigated. The results showed that the presence of nanoscale precipitates favorably affected grain refinement and improved the yield strength. The volume fraction of precipitates increased from 1.05% to 2.85% during tempering, whereas the average precipitate size first decreased then increased during tempering. Contributions to the yield strength arising from the various mechanisms were calculated quantificationally, and the results demonstrated that grain refinement and dislocation density most strongly influenced the yield strength. In addition, under the interaction of average size and volume fraction, precipitates' contribution to the yield strength ranged from 247.9 to 378.5 MPa. Finally, a root-mean-square summation law of σ = σg + σs + (σd 2 + σp 2)1/2, where σg, σs, σd, and σp represent the contributions of fine-grain strengthening, solid-solution strengthening, dislocation strengthening, and precipitation strengthening, respectively, was confirmed as the most applicable for AISI H13 steel, which indicates a strong link between precipitates and dislocations in AISI H13 steel.

  7. Influence of the surface finishing on electrochemical corrosion characteristics of AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    Sylvia Dundeková

    2015-05-01

    Full Text Available Stainless steels from 316 group are very often and successfully uses for medical applications where the good mechanical and chemical properties in combination with non-toxicity of the material assure its safe and long term usage. Corrosion properties of AISI 361L stainless steel are strongly influenced by surface roughness and treatment of the engineering parts (specimens and testing temperature. Electrochemical characteristics of ground, mechanically polished and passivated AISI 316L stainless steel specimens were examined with the aim to identify the polarization resistance evolution due to the surface roughness decrease. Results obtained on mechanically prepared specimens where only natural oxide layer created due to the exposure of the material to the corrosion environment was protecting the materials were compared to the passivated specimens with artificial oxide layer. Also the influence of temperature and stabilization time before measurement were taken into account when discussing the obtained results. Positive influence of decreasing surface roughness was obtained as well as increase of polarization resistance due to the chemical passivation of the surface. Increase of the testing temperature and short stabilization time of the specimen in the corrosion environment were observed negatively influencing corrosion resistance of AISI 316L stainless steel.

  8. Experimental investigation of wear characteristics on TiCN-coated AISI 410 steel

    Science.gov (United States)

    Prabakaran, Vijayasarathi; Sivakumaran, Ilaiyavel; Palimar, Suresh Prabhu

    2016-04-01

    In this work, the dry sliding wear test of uncoated and multilayer TiCN-coated AISI 410 steel against high carbon steel disc recognized at 2.30267 ms-1 sliding speeds and under a three series load of 5, 10 and 20 N at room temperature. On account of the more coherent interface between TiCN and C probably found, there are high hardness and superior wear resistance. Compared to AISI 410 uncoated steel, the presence of C in the multilayer TiCN coatings leads to reduced coefficient of friction and wear loss. The multilayer TiCN coating is characterized by X-ray diffraction analysis, scanning electron microscopy, micro-hardness and pin-on-disc tribometer tests. The more grooving region, pits and ploughing ridge were examined on the worn surface of the AISI 410 uncoated steel. The result shows hard multilayer TiCN-coated particles viewing on the worn surface of the high carbon steel disc.

  9. Análisis de las películas pasivas generadas en aceros inoxidables implantados con cromo

    Directory of Open Access Journals (Sweden)

    Abreu, C. Mª

    2004-06-01

    Full Text Available This work studies the effect of chromium implantation on the development of passive layers generated electrochemically in alkaline medium over two stainless steels. The XPS analyses show that the layers generated on the implanted steels present less thickness together with similar composition compared to the unimplanted steels layers. However, SEM micrographs show that the layers grown on implanted steels present more defects and less adherence that the films on unimplanted steels. These changes together with the results obtained by Cyclic Voltammetry suggest an oxide structure modification, lattice structure or cristalinity state.

    En este trabajo se estudia el efecto de la implantación de cromo en el desarrollo de capas pasivas generadas electroquímicamente en medio básico sobre dos aceros inoxidables (AISI 430 y AISI 304L. Los análisis de XPS muestran que las películas desarrolladas sobre ambos aceros implantados presentan espesores menores, junto con composiciones similares, a las formadas sobre los no implantados. Sin embargo, en los resultados del examen con MEB se puede apreciar que las películas tienen más defectos (agrietamientos y peor adherencia (especialmente en el AISI 430. Este cambio, junto con los datos de voltametría cíclica, parece sugerir una modificación en la estructura de los óxidos, bien en su grado de cristalinidad o bien en la estructura de su red cristalina.

  10. Vida a la fatiga de juntas soldadas del acero inoxidable AISI 316L obtenidas mediante el proceso GMAW

    Directory of Open Access Journals (Sweden)

    Puchi-Cabrera, E. S.

    2007-06-01

    Full Text Available An investigation has been conducted in order to determine the effect of both the metallic transfer mode (pulsed arc or short circuit and the O2 content in the Ar/O2 gas mixture, of the gas-metal arc welding process (GMAW, on the fatigue life under uniaxial conditions of welded joints of 316L stainless steel. It has been concluded that the mixture of the protective gases employed in the process could have an important influence on the fatigue life of the welded joints of such steel in two different ways. Firstly, through the modification of the radius of curvature at the joint between the welding toe and the base metal and, secondly, through a more pronounced degree of oxidation of the alloying elements induced by a higher O2 content in the mixture. As far as the metallic transfer mode is concerned, it has been determined that the welded joints obtained under a pulsed arc mode show a greater fatigue life in comparison with the joints obtained under short circuit for both gas mixtures.

    Se ha llevado a cabo una investigación con la finalidad de determinar el efecto, tanto del modo de transferencia metálica (arco pulsado o cortocircuito como del contenido de O2 en la mezcla de gases protectores Ar/O2, del proceso de soldadura a tope mediante arco metálico con protección gaseosa (GMAW, sobre la vida a la fatiga en condiciones uniaxiales de juntas soldadas del acero inoxidable AISI 316L. Dicho trabajo ha permitido concluir que la composición de la mezcla de gases protectores del proceso GMAW pudiera tener una influencia importante en la vida a la fatiga de las juntas soldadas de dicho material, a través de dos formas distintas: primero, mediante la modificación del radio de curvatura entre la raíz del cordón de soldadura y el metal base y, en segundo lugar, a través del mayor grado de oxidación de los elementos de aleación. En cuanto al modo de transferencia metálica, se determinó que las juntas soldadas mediante arco pulsado

  11. Resistencia a la corrosión de recubrimientos de nitruros metálicos depositados sobre acero AISI M2

    Directory of Open Access Journals (Sweden)

    Jhon Jairo Olaya Florez

    2012-01-01

    Full Text Available En este trabajo se estudia el comportamiento frente a la corrosión de películas de nitruro de zirconio (ZrN, nitruro de titanio (TiN, nitruro de cromo (CrN, nitruro de niobio (NbN y nitruro de tantalio (TaN depositadas sobre acero para herramientas AISI M2 mediante la técnica de sputtering con magnetrón desbalanceado (UBM. La resistencia a la corrosión fue evaluada con ensayos de espectroscopía de impedancia electroquímica (EIS en una solución al 3% de NaCl variando el tiempo de ensayo desde 1 h hasta 7 d. En general, los mejores resultados de resistencia a la corrosión se presentaron en las películas de ZrN y NbN cuando son producidas en la configuración de menor bombardeo iónico en un sistema UBM. Los recubrimientos muestran degradación en el tiempo de ensayo debido a los defectos presentes en su microestructura, que se convierten en canales de difusión por los que la solución corrosiva llega a la superficie del sustrato. Los mecanismos de corrosión para los recubrimientos producidos son discutidos en esta investigación.

  12. Evaluation of performance of AISI 444 steel for application in distillation towers; Avaliacao do desempenho do aco AISI 444 para aplicacao como 'lining' em torres de destilacao

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, R.F.; Miranda, H.C. de; Farias, J.P. [Universidade Federal do Ceara (DEMM/UFC), Fortaleza, CE (Brazil). Dept. de Engenharia Metalurgica e de Materiais. Lab. de Caracterizacao de Materiais], e-mail: rf.guimaraes@yahoo.com.br

    2008-07-01

    In this work, the behavior of the AISI 444 ferritic stainless steel submitted to thermal fatigue test and their corrosion resistance in heavy crude oil was evaluated. The AWS E309MoL-16 and E316L-17 weld metal was employed as filler metal. Plates of the AISI 444 were welded on ASTM A-516 Gr. 60 plates and submitted to fatigue thermal cycle. Samples were extracted from plates welded and heat treated immersed in heavy crude oil at 300 deg C. Optical microscopy (OM), scanning electron microscopy (SEM) and energy dispersive of X-ray analysis (EDX) were used to characterize the microstructure and the corroded surface. The results show that the AISI 444 stainless steels did not present cracks after the thermal fatigue cycle and the heat treated immerse in heavy crude oil. The electrode AWS E309MoL-16 show better corrosion resistance than the AWS E316L-17. (author)

  13. Análisis térmico de soldadura GTAW sobre placa de acero AISI 316L empleando el método de elementos finitos GTAW welding thermal analysis on AISI 316L steel plate using the finite elements method

    Directory of Open Access Journals (Sweden)

    Juan A. Pozo-Morejón

    2011-09-01

    Full Text Available En el presente trabajo se realiza la modelación térmica de soldadura GTAW sobre placa de acero inoxidable AISI 316L. Se analizan los aspectos teóricos más relevantes a considerar durante la ejecución de un análisis de este tipo. En la simulación se emplea un software de análisis por elementos finitos de uso general y se enriquece una metodología, previamente desarrollada, para la modelación en 3D no lineal transitoria del proceso de soldeo. En dicha metodología se implementa una subrutina en lenguaje APDL, programada con el modelo volumétrico de fuente calor de doble elipsoide, en un sistema de coordenadas cartesiano. Se analiza la influencia del paso de tiempo seleccionado sobre los resultados de la simulación. Finalmente se valida la metodología enriquecida, en base a la correlación de los resultados del modelo respecto a los resultados experimentales.In the present work, thermal modeling of GTAW welding on AISI 316L stainless steel plate is presented. More relevant theoretical aspects to be considered during the implementation of an analysis of this type are discussed. For the simulation a general purpose finite element analysis software has been used. A previously developed methodology for 3D nonlinear transient modeling of welding process has also been improved. In this methodology a subroutine in APDL language is implemented, programmed with the double ellipsoid volumetric heat source model, in a Cartesian coordinated system. The influence of the selected time step on the simulation results is analyzed. The good correlation obtained among the results calculated by means of the model and the experimental data validates this improved methodology.

  14. Wear Evaluation of AISI 4140 Alloy Steel with WC/C Lamellar Coatings Sliding Against EN 8 Using Taguchi Method

    Science.gov (United States)

    Kadam, Nikhil Rajendra; Karthikeyan, Ganesarethinam

    2016-10-01

    The purpose of the experiments in this paper is to use the Taguchi methods to investigate the wear of WC/C coated nitrided AISI 4140 alloy steel. A study of lamellar WC/C coating which were deposited by a physical vapor deposition on nitrided AISI 4140 alloy steel. The investigation includes wear evaluation using Pin-on-disk configuration. When WC/C coated AISI 4140 alloy steel slides against EN 8 steel, it was found that carbon-rich coatings show much lower wear of the countersurface than nitrogen-rich coatings. The results were correlated with the properties determined from tribological and mechanical characterization, therefore by probably selecting the proper processing parameters the deposition of WC/C coating results in decreasing the wear rate of the substrate which shows a potential for tribological application.

  15. Preparation of high-performance ultrafine-grained AISI 304L stainless steel under high temperature and pressure

    Directory of Open Access Journals (Sweden)

    Peng Wang

    2016-08-01

    Full Text Available Bulk ultra-fine grained (UFG AISI 304L stainless steel with excellent mechanical properties was prepared by a high-temperature and high-pressure (HTHP method using nanocrystalline AISI 304L stainless steel powders obtained from ball milling. Samples were sintered in high-pressure conditions using the highest martensite content of AISI 304L stainless steel powders milled for 25 h. Analyses of phase composition and grain size were accomplished by X-ray diffraction and Rietveld refinement. By comparing the reverse martensite transformation under vacuum and HTHP treat, we consider that pressure can effectively promote the change in the process of transformation. Compared with the solid-solution-treated 304L, the hardness and yield strength of the samples sintered under HTHP are considerably higher. This method of preparation of UFG bulk stainless steel may be widely popularised and used to obtain UFG metallic materials with good comprehensive performance.

  16. Corrosion Inhibition of AISI 316L and Modified-AISI 630 Stainless Steel by the New Organic Inhibitor [(CH32N]3PSe in Chloride Media:Electrochemical and Physical Study

    Directory of Open Access Journals (Sweden)

    Yafa ZARGOUNI

    2015-04-01

    Full Text Available We evaluate the effect of the Tris-dimethylaminoselenophosphoramide (SeAPon the corrosion inhibition of modified-AISI 630 and AISI 316L stainless steel (SS in 3 wt. % NaCl. The electrochemical behaviors of tested SS samples are investigated before and after adding the Seep into the chloride media by potentiodynamic polarization technique. The adsorption of SeAP onto both SS surfaces is verified by global discharge optical emission spectroscopy (GDOES.  SeAP is found to be a good inhibitor for SS corrosion, especially when added at a concentration of 0.5 wt. %.

  17. Modification and characterization of the AISI 410 martensitic stainless steels surface; Modificacao e caracterizacao da superficie do aco inoxidavel martensitico AISI 410

    Energy Technology Data Exchange (ETDEWEB)

    Bincoleto, A.V.L. [Universidade Federal de Sao Carlos (PPG-CEM/UFSCar), SP (Brazil). Programa de Pos-Graduacao em Ciencia e Engenharia de Materiais; Nascente, P.A.P. [Universidade Federal de Sao Carlos (DEMa/UFSCar), SP (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    Steam turbines are used in the generation of more than half the electric energy produced in the world nowadays. It is important the study which aims to improve the efficiency by means of the optimization of leaks and of the aerodynamic profiles, as well as to maintain the integrity of the components. The martensitic stainless steels are widely employed due to the combination of their good mechanical properties with higher corrosion resistance. However, their lower wear resistance and their poor tribological behavior limit their use, since they decrease the component life time. In order to evaluate the improvement in the performance of the AISI 410 stainless steel, several process of surface modification were employed. Five samples were produced: the first one was not treated, the second one received liquid nitriding, the third, gas nitriding, the forth, thermal aspersion of tungsten carbide, and the fifth, boronizing. The samples were characterized by optical microscopy, surface microhardness, and X-ray diffractometry. (author)

  18. Numerical-experimental analysis of a rin AISI{sub 7}Mg Alloy; Analisis numerico experimental de un rin de aleacion AISi{sub 7}Mg

    Energy Technology Data Exchange (ETDEWEB)

    Sauceda Mesa, Israel; Mata Lucero, Omar; Tirado Delgado, Luis; Ocampo Diaz, Juan de Dios [Universidad Autonoma de Baja California, Mexicali, Baja California (Mexico)

    2005-10-15

    The present work shows the results obtained from an investigation mode on the behaviour of a rin of alloy AISi{sub 7}Mg, which is used in compact Volkswagen's cars. Due to two kind of analysis were realized, firstly an experimental and numerical analysis was done, using a special machine for test the flexionante torque and material fatigue, besides was used an equipment of laser to scanner zone with strength concentrations and the maximum displacement amplitudes. The second analysis was done with the finite element technique, using the software ANSYS and CATIA. The difference between life fatigue cycles obtained from the two analyses was 0.6%. While the time optimize by MEF, was of 85% less than experimental analysis. [Spanish] En el presente trabajo se hicieron investigaciones del comportamiento de un rin de aleacion AISi{sub 7}Mg, el cual es usado en automoviles compactos de volkswagen (VW). Para esto, se realizo analisis experimental y numerico. En el primero se utilizo una maquina para prueba de fatiga de momento flexionante, un equipo de medicion de laser escaner donde se detectaron las zonas de concentraciones de esfuerzos y la maxima amplitud de desplazamiento en el rin. Mientras que en el segundo se obtuvieron los esfuerzos que ocasionaban la fatiga por el elemento finito, utilizando los paquetes de computo Ansys y Catia. La diferencia de los ciclos de vida de fatiga obtenidos entre ambos analisis fue del 0.6%. Mientras que el tiempo que se optimizo por el MEF, fue de un 85% menos que el analisis experimental.

  19. Characterization Of Oxide Layers Produced On The AISI 321 Stainless Steel After Annealing

    Directory of Open Access Journals (Sweden)

    Bochnowski W.

    2015-09-01

    Full Text Available In this study, the structure, chemical composition and topography of oxide layers produced on the surface of the AISI 321 austenitic steel in the annealing process were analyzed. Heat treatment was done at 980°C temperature for 1 hour time in different conditions. The annealing was done in a ceramic furnace in oxidation atmosphere and in vacuum furnaces with cylindrical molybdenum and graphite chambers. The analysis was carried out using the following methods: a scanning electron microscope (SEM equipped with an energy-dispersive X-ray spectrometer (EDX, a transmission electron microscope (TEM equipped with an energy-dispersive X-ray spectrometer (EDX, an X-ray diffractometer (XRD, a secondary ion mass spectrometer with time-of-flight mass analyzer (TOF SIMS and an atomic force microscope (AFM. The oxide layer formed during annealing of the AISI 321 steel at 980°C consisted of sub-layers, diversified in the chemical composition. The thickness of the oxidized layer is depended on the annealing conditions. In a ceramic furnace in oxidation atmosphere, the thickness of the oxide layer was of 300-500 nm, in a vacuum furnace with molybdenum and graphite heating chambers, it ranged from 40 to 300 nm and from a few to 50 nm, respectively. TOF SIMS method allows to get average (for the surface of 100 μm × 100 μm depth profiles of concentration of particular elements and elements combined with oxygen. In oxide layers formed in vacuum furnaces there are no iron oxides. Titanium, apart from being bounded with carbon in carbides, is a component of the oxide layer formed on the surface of the AISI 321 steel.

  20. Electrochemical and pitting corrosion resistance of AISI 4145 steel subjected to massive laser shock peening treatment with different coverage layers

    Science.gov (United States)

    Lu, J. Z.; Han, B.; Cui, C. Y.; Li, C. J.; Luo, K. Y.

    2017-02-01

    The effects of massive laser shock peening (LSP) treatment with different coverage layers on residual stress, pitting morphologies in a standard corrosive solution and electrochemical corrosion resistance of AISI 4145 steel were investigated by pitting corrosion test, potentiodynamic polarisation test, and SEM observations. Results showed massive LSP treatment can effectively cause an obvious improvement of pitting corrosion resistance of AISI 4145 steel, and increased coverage layer can also gradually improve its corrosion resistance. Massive LSP treatment with multiple layers was shown to influence pitting corrosion behaviour in a standard corrosive solution.

  1. An Electrochemical Impedance Study of AISI 321 Stainless Steel in 0.5 M H2SO4

    Directory of Open Access Journals (Sweden)

    A. Fattah-Alhosseini

    2011-01-01

    Full Text Available The electrochemical behavior of passive films formed on AISI 321 has been examined using electrochemical impedance spectroscopy. AISI 321 is characterized by high interfacial impedance, thereby illustrating its high corrosion resistance. Results showed that the interfacial impedance and the polarization resistance initially increase with applied potential, within the low potential. However, at a sufficiently high potential (>0.6 V, the interfacial impedance and the polarization resistance decrease with increasing potential. The impedance data were adequately represented by an equivalent electrical circuit model based on point defect model, which described the behavior of the passive film on stainless steel more satisfactorily than the proposed models.

  2. Estructura cristalina del acero AISI 1045 deformado plásticamente

    Directory of Open Access Journals (Sweden)

    Tomás Fernández Columbié

    2008-01-01

    Full Text Available Se abordó el comportamiento microestructural del acero AISI 1045 endurecido mediante la Deformación Plástica Superficial por rodillo, Se establece el mecanismo de endurecimiento del acero por el deslizamiento de los granos en la red cristalina y se demuestra el fenómeno de la acritud, la cual es producto del tensionamiento de los granos cuando el material es sometido al tensionamiento de su estructura cristalina. Se establece el procedimiento experimental realizado después que las probetas fueron sometidas al proceso de deformación.

  3. Estructura cristalina del acero AISI 1045 deformado plásticamente

    OpenAIRE

    Tomás Fernández Columbié; Isnel Rodríguez González; Dayanis Alcántara Borges

    2008-01-01

    Se abordó el comportamiento microestructural del acero AISI 1045 endurecido mediante la Deformación Plástica Superficial por rodillo, Se establece el mecanismo de endurecimiento del acero por el deslizamiento de los granos en la red cristalina y se demuestra el fenómeno de la acritud, la cual es producto del tensionamiento de los granos cuando el material es sometido al tensionamiento de su estructura cristalina. Se establece el procedimiento experimental realizado después que las probetas fu...

  4. Variación microestructural del acero AISI 1045 endurecido por rodadura

    OpenAIRE

    Esther Fernández-Guilarte; Dayanis Alcántara-Borges; Isnel Rodríguez-González; Tomás Fernández-Columbié

    2010-01-01

    En este trabajo se analiza el comportamiento microestructural del acero AISI 1045, endurecido mediante deformación plástica superficial por rodillo, empleando como variables en el proceso de endurecimiento el número de revoluciones, avance y fuerza del torno 16D20. Se empleó el análisis espectral para determinar la composición química del acero y el Nital como reactivo químico para resaltar la estructura metalográfica después de pulida. Se establecen los parámetros de los regímenes de la defo...

  5. Estimation of embrittlement during aging of AISI 316 stainless steel TIG welds

    Indian Academy of Sciences (India)

    J Nayak; K R Udupa; K R Hebbar; H V S Nayak

    2004-12-01

    Weldments of AISI grade 316 stainless steel, having a ferrite content of 4–6% and a variety of nitrogen concentrations were prepared using a modified element implant technique. Charpy impact specimens prepared from these weldments were subjected to a variety of aging treatments. Impact toughness decreases with aging time at all aging temperatures. Nitrogen is found to be beneficial to toughness. An empirical relation connecting the aging temperature, aging time and nitrogen content with toughness has been developed which can be used to estimate the time for embrittlement.

  6. Biaxial fatigue tests of notched specimens for AISI 304L stainless steel

    Directory of Open Access Journals (Sweden)

    G. Beretta

    2016-07-01

    Full Text Available High cycle fatigue tests were conducted for stainless steel AISI 304L. The geometry was a thin walled tube with a passing through hole. The tests were axial, torsional and in-phase axial-torsional, all of them under load control with R = −1. The S-N curves were constructed following the ASTM E739 standard and the fatigues limits were calculated following the method of maximum likelihood proposed by Bettinelli. The crack direction along the surface was analysed, with especial attention to the crack initiation zones. The notch fatigue limits for different hole diameters were compared with the predictions done with a microstructural fracture mechanics model.

  7. HTS SQUID application for measuring the magnetic properties of AISI type 316L(N) steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, D.G. E-mail: dgpark@nanum.kaeri.re.kr; Kim, D.W.; Hong, J.H.; Timofeev, V.P.; Kim, C.G

    2000-06-02

    A portable RF HTS SQUID-based susceptometer was used for small-size magnetized sample testing in weak DC (up to 200 A/m) and AC (up to 4 A/m) magnetic fields. The system resolution for the magnetic moment is of the order of 1.6x10{sup -10} A m{sup 2}. The measured DC susceptibility of a tested sample of Gd{sub 88}La{sub 12} agrees well with the value obtained by using a commercial liquid helium susceptometer. The measured volume susceptibility of AISI type 316L(N) steel increases after fatigue due to the microcrack induced by cyclic stress.

  8. Microstructural changes due to laser surface melting of an AISI 304 stainless steel

    Directory of Open Access Journals (Sweden)

    d?Oliveira A.S.C.M.

    2001-01-01

    Full Text Available Several techniques can be used to improve surface properties. These can involve changes on the surface chemical composition (such as alloying and surface welding processes or on the surface microstructure, such as hardening and melting. In the present work surface melting with a 3kW CO2 cw laser was done to alter surface features of an AISI 304 stainless steel. Microstructure characterisation was done by optical and scanning electron microscopy. Vickers and Knoop microhardness tests evaluated mechanical features after surface melting. Phase transformation during rapid solidification is analysed and discussed.

  9. PITTING CORROSION OF AISI 316Ti STAINLESS STEEL WITH POLISHED SURFACE

    Directory of Open Access Journals (Sweden)

    Viera Zatkalíková

    2010-05-01

    Full Text Available AISI 316Ti is Cr–Ni–Mo austenitic stainless steel with the high Pitting Resistance Equivalent Number (PREN. The effect of the surface finishing by polishing on the pitting corrosion resistance was tested in aggressive 5% FeCl3 solution. The immersion tests were curried out at the temperature 30, 50, 80 °C. The electrochemical cyclic potentiodynamic tests were carried out in the same solution at temperature 30 and 50 °C. The evaluation of the corrosion resistance arose from the comparison of the results of the immersion and the cyclic potentiodynamic tests.

  10. 1020 AISI-SAE steel Austenitic Nitrocarburising with alcohol and triethanolamine

    Directory of Open Access Journals (Sweden)

    Álvaro Castro P

    2010-04-01

    Full Text Available The present work shows AISI-SAE 1020 steel's nitrocarbide layer's microstructure and micro-hardness profile following 4 hours at 700ºC using methanol, isopropanol and triethanolamine. The steel was then hardened by quenching it in water and then tempered at 350ºC for 1 hour. Its surface had been partially oxidised by heating it at 400ºC for 1 hour. An example is given of other researchers analysing microstructure and propierties in steel having 0,5% C, using endothermic gas and different amounts of ammoniac.

  11. The structural characterization of some biomaterials, type AISI 310, used in medicine

    Science.gov (United States)

    Minciuna, M. G.; Vizureanu, P.; Hanganu, C.; Achitei, D. C.; Popescu, D. C.; Focsaneanu, S. C.

    2016-06-01

    Orthopedics biomaterials are intended for implantation in the human body and substituted or help to repair of bones, cartilage or organ transplant, and tendons. At the end of the 20th century, the availability of materials for the manufacture implants used in medicine has been the same as for other industrial applications. The most used metals for manufacturing the orthopedics implants are: stainless steels, cobalt-chrome-molybdenum alloys, titanium and his alloys. The structural researches which are made in this paper, offer a complete analysis of AISI310 stainless steels, using: optical spectrometry, X-ray diffraction and scanning electronic microscopy.

  12. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  13. Mechanical Properties of Stellite-6 coated AISI 316L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Pushpinderjit Singh

    2016-01-01

    Full Text Available Present paper describes the mechanical properties of Stellite-6 coated AISI 316 L stainless steel. Specimens were coated using Detonation Gun thermal spray process, with different coating thicknesses of Stellite-6 ranging from 50 µm to 150 µm. Afterwards their properties like tensile strength, impact strength and micro hardness were evaluated on the basis of the results obtained from the experimentation. For comparison of substrate and coated material the graphs were plotted. The coated specimens exhibited superior impact strength and microhardness than that of the bare specimens, whereas the tensile strength of coated specimens decreased marginally with the increase in coating thickness.

  14. Investigating early stages of biocorrosion with XPS: AISI 304 stainless steel exposed to Burkholderia species

    Science.gov (United States)

    Johansson, Leena-Sisko; Saastamoinen, Tuomas

    1999-04-01

    We have investigated the interactions of an exopolymer-producing bacteria, Burkholderia sp. with polished AISI 304 stainless steel substrates using X-ray photoelectron spectroscopy (XPS). Steel coupons were exposed to the pure bacteria culture in a specially designed flowcell for 6 h during which the experiment was monitored in situ with an optical microscope. XPS results verified the formation of biofilm containing extracellular polymer on all the samples exposed to bacteria. Sputter results indicated that some ions needed for metabolic processes were trapped within the biofilm. Changes in the relative Fe concentration and Fe 2p peak shape indicated that also iron had accumulated into the biofilm.

  15. Caracterización de capas coloreadas sobre AISI 304

    Directory of Open Access Journals (Sweden)

    López, J.

    1998-05-01

    Full Text Available A common method for obtaining colour coatings on stainless steel surfaces is by dipping in strongly oxidizing solutions (H2SO4-CrO3 at 70°C. This work improves the knowledge of these coatings by means of techniques that were not available some years ago, such as ellipsometry, to determine the refraction index and the thickness, and atomic field microscopy (AFM, to observe the coloured surface. From these techniques, it is possible to state that films are formed by an aggregation of particle ranging in size from 5 to 15 nm, the interstices are pores of approximately 5 nm diameter.

    El método más usual de obtener en la superficie de los aceros inoxidables capas de colores variables es mediante su inmersión en soluciones fuertemente oxidantes (H2SO4-CrO3 a una temperatura en torno a 70°C. El trabajo mejora el conocimiento que de estas capas se tiene por medio de técnicas que no eran disponibles hace algunos años, tales como la elipsometría, para la obtención de parámetros ópticos y determinación de espesores, y la microscopía de campo atómico, para la observación de la superficie coloreada. El uso conjunto de estas técnicas permite observar que la película de color está formada por una agregación de partículas con un tamaño que oscila entre los 5 y los 15 nm, los intersticios que aparecen entre las partículas pueden identificarse como poros de unos 5 nm de tamaño.

  16. Recubrimientos de aluminio-silicio realizados por deposición química de vapor en lecho fluidizado sobre el acero inoxidable AISI 316

    Directory of Open Access Journals (Sweden)

    José Luddey Marulanda Arevalo

    2013-12-01

    Full Text Available Los recubrimientos de aluminio-silicio fueron depositados sobre el acero inoxidable AISI 316 mediante deposición química de vapor en lecho fluidizado (CVD-FBR, en el rango de temperaturas de 540 a 560 ºC, utilizando un lecho formado por 2,5 g de silicio y 7,5 g de aluminio en polvo, y 90 g de lecho inerte (Alúmina, el cual se hizo fluidizar con Ar. Como gases activadores se usó una mezcla de HCl/H2, en relaciones de 1/10 a 1/16. Además, se varió el tiempo de deposición de los recubrimientos de 45 minutos a 1.5 horas, con una relación en volumen de 50% de gases activos y 50% de gases neutros. Se realizó una simulación termodinámica con la ayuda del programa informático Thermocalc, para obtener información de la posible composición y cantidad de material depositado, para las condiciones seleccionadas. En los recubrimientos se encuentran FeAl2Si, Fe2Al5 y FeAl2. Los recubrimientos aluminio-silicio fueron tratados térmicamente, para mejorar sus propiedades mecánicas y su comportamiento frente a la oxidación, por la interdifusión de los elementos de aleación, ya que el tratamiento térmico hace que el aluminio difunda hacia el substrato, y el hierro difunda hacia la superficie del recubrimiento, logrando la transformación de los compuestos anteriores en FeAl, Al2FeSi, Cr3Si, AlCrFe y AlFeNi.

  17. Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Ehrnsten, U.; Toivonen, A. [Materials and Structural Integrity, VTT Technical Research Centre of Finland, Kemistintie 3, P.O. Box 1704, FIN-02044 VTT (Finland); Ivanchenko, M.; Nevdacha, V.; Yagozinskyy, Y.; Haenninen, H. [Department of Mechanical Engineering, Helsinki University of Technology Puumiehenkuja 3, P.O. Box 4200, FIN-02015 HUT (Finland)

    2004-07-01

    Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)

  18. Improving by postoxidation of corrosion resistance of plasma nitrocarburized AISI 316 stainless steels

    Science.gov (United States)

    Yenilmez, A.; Karakan, M.; Çelik, İ.

    2017-01-01

    Austenitic stainless steels are widely used in several industries such as chemistry, food, health and space due to their perfect corrosion resistance. However, in addition to corrosion resistance, the mechanic and tribological features such as wear resistance and friction are required to be good in the production and engineering of this type of machines, equipment and mechanic parts. In this study, ferritic (FNC) and austenitic (ANC) nitrocarburizing were applied on AISI 316 stainless steel specimens with perfect corrosion resistance in the plasma environment at the definite time (4 h) and constant gas mixture atmosphere. In order to recover corrosion resistance which was deteriorated after nitrocarburizing again, plasma postoxidation process (45 min) was applied. After the duplex treatment, the specimens' structural analyses with XRD and SEM methods, corrosion analysis with polarization method and surface hardness with microhardness method were examined. At the end of the studies, AISI 316 surface hardness of stainless steel increased with nitrocarburizing process, but the corrosion resistance was deteriorated with FNC (570 °C) and ANC (670 °C) nitrocarburizing. With the following of the postoxidation treatment, it was detected that the corrosion resistance became better and it approached its value before the process.

  19. Determination of Proper Austenitization Temperatures for Hot Stamping of AISI 4140 Steel

    Science.gov (United States)

    Samadian, Pedram; Parsa, Mohammad Habibi; Shakeri, Amid

    2014-04-01

    High strength steels are desirable materials for use in automobile bodies in order to reduce vehicle weight and increase the safety of car passengers, but steel grades with high strength commonly show poor formability. Recently, steels with controlled microstructures and compositions are used to gain adequate strength after hot stamping while maintaining good formability during processing. In this study, microstructure evolutions and changes in mechanical properties of AISI 4140 steel sheets resulting from the hot stamping process at different austenitization temperatures were investigated. To determine the proper austenitization temperatures, the results were compared with those of the cold-worked and cold-worked plus quench-tempered specimens. Comparisons showed that the austenitization temperatures of 1000 and 1100 °C are proper for hot stamping of 3-mm-thick AISI 4140 steel sheets due to the resultant martensitic microstructure which led to the yield and ultimate tensile strength of 1.3 and 2.1 GPa, respectively. Such conditions resulted in more favorable simultaneous strength and elongation than those of hot-stamped conventional boron steels.

  20. PARAMETRIC STUDY OF ELECTRICAL DISCHARGE MACHINING OF AISI 304 STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    P. SRINIVASA RAO,

    2010-08-01

    Full Text Available Electrical discharge machining (EDM is widely used process in the production of mould / dies, aerospace, automobile and electronics industries where intricate complex shapes need to be machined in very hard materials. The selection of the AISI 304 stainless steel was made taking into account its use in almost all industrial applicationsfor approximately 50% of the world’s stainless steel production and consumption. In this work, a study has been carried out on the influence of four design factors: current, open-circuit voltage, servo and dutycycle over material removal rate, tool wear rate, surface roughness and hardness on the die-sinking electrical discharge machining of AISI 304 stainless steel. This has been done using design of experiments (DOE, which allows us to carry out theabove-mentioned analysis performing a relatively small number of experiments. In this case, a 3*24-1 mixed level factorial design, whose resolution is V, has been selected due to the number of factors considered in the study. The resolution of this mixed factorial design allows us to estimate all the main effects, two-factor interactions and pure quadratic effects of the four design factors selected to perform this study.

  1. Improving electrochemical properties of AISI 1045 steels by duplex surface treatment of plasma nitriding and aluminizing

    Energy Technology Data Exchange (ETDEWEB)

    Haftlang, Farahnaz, E-mail: f.haftlang@students.semnan.ac.ir [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Habibolahzadeh, Ali [Department of Metallurgy and Materials Engineering, Faculty of Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Sohi, Mahmoud Heydarzadeh [School of Metallurgy and Materials, College of Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2015-02-28

    Highlights: • AlN coating was applied on AISI 1045 steel via plasma nitriding and aluminizing. • Plasma nitriding and post-aluminizing result in AlN single phase layer on the steel. • PN–Al coated steel had better corrosion resistance than Al–PN one. • Formation of oxide layer provided protection of PN–Al coated steel against corrosion. • Pitting and surface defects was the dominant corrosion mechanism in Al–PN coated steel. - Abstract: Improvement in electrochemical behavior of AISI 1045 steel after applying aluminum nitride coating was investigated in 3.5% NaCl solution, using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) analyses. Aluminum nitride coating was applied on the steel surface by duplex treatment of pack aluminizing and plasma nitriding. Some specimens were plasma nitrided followed by aluminizing (PN–Al), while the others were pack aluminized followed by plasma nitriding (Al–PN). Topological and structural studies of the modified surfaces were conducted using scanning electron microscope (SEM) equipped by energy dispersive X-ray spectroscope (EDS), and X-ray diffractometer (XRD). The electrochemical measurements showed that the highest corrosion and polarization (R{sub p}) resistances were obtained in PN–Al specimens, having single phase superficial layer of AlN. Pitting mechanism was dominant reason of lower corrosion resistance in the Al–PN specimens.

  2. Structural and Microhardness Changes After Turning of the AISI 1045 Steel for Minimum Quantity Cooling Lubrication

    Science.gov (United States)

    Maruda, Radoslaw W.; Krolczyk, Grzegorz M.; Michalski, Mariusz; Nieslony, Piotr; Wojciechowski, Szymon

    2017-01-01

    This work presents the cooling effect under minimum quantity cooling lubrication and dry cutting on structural changes and microhardness of the ferritic-pearlitic AISI 1045 steel after turning. Due to the fact that the AISI 1045 steel has a two-phase structure, microhardness tests using the Vickers method were conducted with a load of 0.05 HV separately for ferrite and pearlite grains. The tests showed that cooling of the cutting zone under minimum quantity cooling lubrication (MQCL) condition decreased the depth of the hardened layer compared to dry cutting by approximately 40% for both pearlite and ferrite. Scanning electron microscopy analysis revealed that applying MQCL limits the formation of plastic deformations, among others, by reducing the surface crumple zone by approximately 50% compared to dry cutting. As a result of cooling being applied to the cutting zone using the MQCL method, the average diameter of ferrite grains has been decreased in the entire surface area compared to dry cutting. When using dry cutting, clear structural changes of the surface layer were also observed. This may be the result of sulfide inclusions which have formed, causing microcracks on the edge of the hardened layer and surface deformation visible as notches.

  3. Improvement in cavitation erosion resistance of AISI 316L stainless steel by friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Hajian, M. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Abdollah-zadeh, A., E-mail: zadeh@modares.ac.ir [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Rezaei-Nejad, S.S.; Assadi, H. [Department of Materials Engineering, Tarbiat Modares University, P.O. Box 14115-143, Tehran (Iran, Islamic Republic of); Hadavi, S.M.M. [Department of Materials Science and Engineering, MA University of Technology, Tehran (Iran, Islamic Republic of); Chung, K. [Department of Materials Science and Engineering, Research Institute of Advanced Materials, Engineering Research Institute, Seoul National University, Seoul (Korea, Republic of); Shokouhimehr, M. [Department of Chemical Engineering, College of Engineering, Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-07-01

    Commercial AISI 316L plates with the initial grain size of 14.8 μm were friction stir processed (FSP) with different processing parameters, resulting in two fine-grained microstructures with the grain sizes of 4.6 and 1.7 μm. The cavitation erosion behavior, before and after FSP, was evaluated in terms of incubation time, cumulative mass loss and mean depth of erosion. A separate cavitation erosion test was performed on the transverse cross section of a FSP sample to reveal the effect of grain structure. It was observed that FSP samples, depending on their grain size, are at least 3–6 times more resistant than the base material against cavitation erosion. The improvement in cavitation erosion resistance is attributed to smaller grain structure, lower fraction of twin boundaries, and favorable crystallographic orientation of grains in FSP samples. The finer the grain size, the more cavitation erosion resistance was achieved. Moreover, the microstructures of eroded surfaces were studied using a scanning electron microscope equipped with EBSD, and an atomic force microscope. The mechanisms controlling the cavitation erosion damage in friction stir processed AISI 316L are also discussed.

  4. Physical and Tribological Properties of Nitrided AISI 316 Stainless Steel Balls

    Directory of Open Access Journals (Sweden)

    Yang Shicai

    2016-01-01

    Full Text Available AISI 316 austenitic stainless steel balls (diameters 5.0 and 12.0 mm, typical hardness 250 HV0.3 and flat samples (20×20×2.0 mm were nitrided by a pulsed glow discharge Ar/N2 plasma. Hardness of the ball surfaces was analysed using Vickers indentation. Thermal stability of the nitrided balls (diameter 12.0 mm was studied using a furnace to heat them in air for 8 hours at temperatures up to 700.0°C and then, after cooling to room temperature, the surface hardness of the heated balls was re-measured. Scanning electron microscopy and X-ray diffraction were used to study the microstructures, composition and phase formation of the nitrided sublayers. Unlubricated pin-on-disc wear testing was used to evaluate the wear resistance of nitrided stainless steel balls (5.0 mm diameter and the results were compared with similar testing on hardened Cr-Steel balls (5 mm diameter with hardness of about 650 HV0.3. All the test results indicated that the nitrided AISI 316 austenitic stainless steel balls have advantages over the hardened Cr-Steel balls in terms of retaining high hardness after heat treatment and high resistance to sliding wear at room temperature under higher counterpart stress. These properties are expected to be beneficial for wide range of bearing applications.

  5. Friction welding of AA6061 to AISI 4340 using silver interlayer

    Directory of Open Access Journals (Sweden)

    Suresh D. Meshram

    2015-09-01

    Full Text Available The present work pertains to the study on joining of AA6061 and AISI 4340 through continuous drive friction welding. The welds were evaluated by metallographic examination, X-ray diffraction, electron probe microanalysis, tensile test and microhardness. The study reveals that the presence of an intermetallic compound layer at the bonded interface exhibits poor tensile strength and elongation. Mg in AA6061 near to the interface is found to be favourable for the formation and growth of Fe2Al5 intermetallics. Introduction of silver as an interlayer through electroplating on AISI 4340 resulted in accumulation of Si at weld interface, replacing Mg at AA6061 side, thereby reducing the width of intermetallic compound layer and correspondingly increasing the tensile strength. Presence of silver at the interface results in partial replacement of Fe–Al based intermetallic compounds with Ag–Al based compounds. The presence of these intermetallics was confirmed by X-ray diffraction technique. Since Ag–Al phases are ductile in nature, tensile strength is not deteriorated and the silicon segregation at weld interface on AA6061 in the joints with silver interlayer acts as diffusion barrier for Fe and further avoids formation of Fe–Al based intermetallics. A maximum tensile strength of 240 MPa along with 4.9% elongation was obtained for the silver interlayer dissimilar metal welds. The observed trends in tensile properties and hardness were explained in relation to the microstructure.

  6. Microstructure and Properties of Plasma Source Nitrided AISI 316 Austenitic Stainless Steel

    Science.gov (United States)

    Li, G. Y.; Lei, M. K.

    2016-11-01

    Plasma source nitriding is a relatively new nitriding technology which can overcome those inherent shortcomings associated with conventional direct current plasma nitriding technology such as the arcing surface damage, the edging effect and the hollow cathode effect. There is considerable study on the properties of nitrided samples for laboratorial scale plasma source nitriding system; however, little information has been reported on the industrial-scale plasma source nitriding system. In this work, AISI 316 austenitic stainless steel samples were nitrided by an industrial-scale plasma source nitriding system at various nitriding temperatures (350, 400, 450 and 500 °C) with a floating potential. A high-nitrogen face-centered-cubic phase (γN) formed on the surface of nitrided sample surface. As the nitriding temperature was increased, the γN phase layer thickness increased, varying from 1.5 μm for the lowest nitriding temperature of 350 °C, to 30 μm for the highest nitriding temperature of 500 °C. The maximum Vickers microhardness of the γN phase layer with a peak nitrogen concentration of 20 at.% is about HV 0.1 N 15.1 GPa at the nitriding temperature of 450 °C. The wear and corrosion experimental results demonstrated that the γN phase was formed on the surface of AISI 316 austenitic stainless steel by plasma source nitriding, which exhibits not only high wear resistance, but also good pitting corrosion resistance.

  7. Statistical regression modeling and machinability study of hardened AISI 52100 steel using cemented carbide insert

    Directory of Open Access Journals (Sweden)

    Amlana Panda

    2017-01-01

    Full Text Available The present study investigates performance and feasibility of application of low cost cemented carbide insert in dry machining of AISI 52100 steel hardened to (55 ± 1 HRC which is rarely researched as far as machining of bearing steel is concerned. Machinability studies i.e. flank wear, surface roughness and morphology analysis of chip has been investigated and statistical regression modeling has been developed. The test has been conducted based on Taguchi L16 OA taking machining parameters like cutting speed, feed and depth of cut. It is observed that uncoated cemented carbide insert performs well at some selected runs (Run 1, 5 and 9 which show its feasibility for hard turning applications. The developed serrated saw tooth chip of burnt blue colour adversely affects the surface quality. Adequacy of the developed statistical regression model has been checked using ANOVA analysis (depending on F value, P value and R2 value and normal probability plot at 95% confidence level. The results of optimal parametric combinations may be adopted while turning hardened AISI 52100 steel under dry environment with uncoated cemented carbide insert.

  8. Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes

    Science.gov (United States)

    Umbrello, Domenico; Rizzuti, Stefania; Outeiro, José C.; Shivpuri, Rajiv

    2007-04-01

    In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change.

  9. Pitting and Intergranular Corrosion Resistance of AISI Type 301LN Stainless Steels

    Science.gov (United States)

    Ningshen, S.; Kamachi Mudali, U.

    2010-03-01

    The pitting and intergranular corrosion (IGC) resistance of AISI type 301LN stainless steels were evaluated using ASTM methods, anodic polarization, and electrochemical impedance techniques. The IGC results indicated that the microstructure of the samples after sensitization heat treatment at 675 °C for 1 h shows step or dual structure for both imported and indigenous materials indicating insignificant Cr23C6 precipitation. The results of immersion tests in boiling 6% copper sulfate + 16% sulfuric acid + copper solution for 24 h followed by the bend test (ASTM A262 Practice-E method) indicated no crack formation in any of the tested specimens. Pitting corrosion resistance carried out in 6% FeCl3 solution at different temperatures of 22 ± 2 and 50 ± 2 °C (ASTM G 48) up to the period of 72 h revealed pitting corrosion attack in all the investigated alloys. The potentiodynamic anodic polarization results in 0.5 M NaCl revealed variation in passive current density and pitting potential depending on the alloy chemistry and metallurgical condition. The passive film properties studied by electrochemical impedance spectroscopy (EIS) correlated well with the polarization results. The x-ray diffraction (XRD) results revealed the presence of austenite (γ) and martensite (α') phases depending on the material condition. The suitability of three indigenously developed AISI type 301LN stainless steels were compared with imported type 301LN stainless steel and the results are highlighted in this article.

  10. The effect of cladding speed on phase constitution and properties of AISI 431 stainless steel laser deposited coatings

    NARCIS (Netherlands)

    Hemmati, I.; Ocelik, V.; De Hosson, J. Th. M.

    2011-01-01

    Shorter processing time has given impetus to laser cladding technology and therefore in this research the AISI 431 martensitic stainless steel coatings are laser deposited at high cladding speeds, i.e. up to 117 mm/s. The analysis of phase constitution and functional properties of the coatings are p

  11. Effects of Ultrasonic Nanocrystal Surface Modification (UNSM) on Residual Stress State and Fatigue Strength of AISI 304

    Science.gov (United States)

    Cherif, A.; Pyoun, Y.; Scholtes, B.

    2010-03-01

    The effects of a new mechanical surface treatment method, called ultrasonic nanocrystal surface modification (UNSM), on near-surface microstructures and residual stress states as well as on the fatigue behavior of an austenitic steel AISI 304 are investigated and discussed. The results are compared with consequences of other mechanical surface treatment methods such as deep rolling or shot peening.

  12. Extended X-Ray Absorption Fine Structure Investigation of Carbon Stabilized Expanded Austenite and Carbides in Stainless Steel AISI 316

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas; Ståhl, Kenny;

    2011-01-01

    Low temperature carburized AISI 316 stainless steel - carbon expanded austenite - was investigated with EXAFS and synchrotron diffraction together with synthesized carbides of the type M3C2, M7C3 and M23C6. It was found that the chemical environment of carbon expanded austenite is not associated ...

  13. CATALIZADOR ESTRUCTURADO DE Pt/Al2O3 SOBRE UNA ESPUMA DE ACERO INOXIDABLE (AISI 314 PARA LA OXIDACIÓN DE CO

    Directory of Open Access Journals (Sweden)

    Juan P. Bortolozzi

    2011-01-01

    Full Text Available Se obtuvo un catalizador estructurado por recubrimiento de Pt/Al2O3 sobre las paredes de una espuma de acero inoxidable AISI 314. Para estabilizar térmicamente e incrementar la rugosidad de la superficie de la espuma original se realizó un tratamiento a 900°C por 2 h. El soporte, Al2O3, y el metal activo, Pt, se incorporaron por inmersión. Las técnicas de caracterización aplicadas, XRD, LRS y SEM-EDX, permiten concluir que el tratamiento térmico previo indujo la formación de óxido de cromo y de las espinelas Mn1+xCr2-xO4-x y FeCr2O4 como fases principales en las paredes del sustrato. El espesor de la capa formada es cercano a 1 μm y los cristales producidos tienen forma octaédrica. El cubrimiento de alúmina presentó en general una apariencia homogénea, sin interacción con los óxidos formados durante el tratamiento. El Pt se distribuyó de manera uniforme, resultando un catalizador muy activo para la reacción test elegida: oxidación de monóxido de carbono.

  14. Oxidation behaviour at 1123 K of AISI 304-Ni/Al-Al2O3/TiO2 multilayer system deposited by flame spray

    Directory of Open Access Journals (Sweden)

    Cervera, I.

    2011-04-01

    ética DW·S–1 (mg.mm–2 vs. tiempo (horas se ha ajustado a una ley parabólica para todas las muestras. La composición superficial de la capa cerámica y la sección transversal del sistema multicapa se han analizado mediante las técnicas de Microscopía Electrónica de Barrido (SEM, Espectroscopia de Energías Dispersivas de Rayos X (EDX, Difracción de Rayos X (XRD antes y después del proceso de oxidación. Los recubrimientos 97/3 y 87/13 han presentado una estructura estable tras el proceso de deposición por proyección por llama y esta estructura tampoco ha evolucionado después de la oxidación, mientras la mayor parte del recubrimiento 60/40 ha cambiado a una estructura metaestable después la deposición y finalmente ha evolucionado a una estructura más estable después de la oxidación con alto contenido de microagrietamiento. El microanálisis mediante SEM y EDX de las secciones transversales han mostrado una oxidación significativa en la capa de enganche y una débil precipitación intergranular en el material base AISI 304.

  15. Effect of the powder particle size on the wear behavior of boronized AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Guenen, Ali [Mustafa Kemal Univ., Hatay (Turkey). Dept. of Metallurgy and Material Engineering; Kuecuek, Yilmaz; Oege, Mecit; Goek, M. Sabri [Bartin Univ. (Turkey). Dept. of Mechanical Engineering; Er, Yusuf [Firat Univ., Elazig (Turkey); Cay, V. Veli [Dicle Univ., Diyarbakir (Turkey). Civil Aviation Higher School

    2015-06-01

    In this study, the AISI 304 steel specimens were boronized with nanoboron of the size of 10 50 nm and commercial Ekabor 3 powders (<1400 μm) at 950 C to 1000 C for 2 h and 4 h. Boronized steel specimens were characterized via SEM, microhardness and XRD analyses. Abrasive wear behavior of the specimens, boronized at different temperatures and treatment durations, were examined. The fixed ball micro-abrasion tests were carried out using the abrasive slurry, prepared with different SiC powder particle sizes on the boronized specimens at different rotational speeds. The specimens boronized with nanoboron powders exhibited a higher hardness and abrasive wear resistance than the samples boronized with the Ekabor 3 powders.

  16. Corrosion behavior of low energy, high temperature nitrogen ion-implanted AISI 304 stainless steel

    Indian Academy of Sciences (India)

    M Ghorannevis; A Shokouhy; M M Larijani; S H Haji Hosseini; M Yari; A Anvari; M Gholipur Shahraki; A H Sari; M R Hantehzadeh

    2007-01-01

    This work presents the results of a low-energy nitrogen ion implantation of AISI 304 type stainless steel (SS) at a moderate temperature of about 500° C. The nitrogen ions are extracted from a Kauffman-type ion source at an energy of 30 keV, and ion current density of 100 A cm-2. Nitrogen ion concentration of 6 × 1017, 8 × 1017 and 1018 ions cm-2, were selected for our study. The X-ray diffraction results show the formation of CrN polycrystalline phase after nitrogen bombardment and a change of crystallinity due to the change in nitrogen ion concentration. The secondary ion mass spectrometry (SIMS) results show the formation of CrN phases too. Corrosion test has shown that corrosion resistance is enhanced by increasing nitrogen ion concentration.

  17. The Investigation of Surface Roughness on AISI 1040 Steel with Dry Turning

    Directory of Open Access Journals (Sweden)

    Nergizhan Kavak

    2012-12-01

    Full Text Available In this study, the effect of cutting speed and feed rate on the surface roughness was investigated experimentaly in the machining of AISI 1040 steel being mostly used in industry. Experiments was done by dry turning with uncoated cementite carbite cutting tools at different speeds (46. 91 ve 128 m/dk and feed rates (0.16, 0.22 ve 0.28 mm/dev while cutting depth stays stable at 2 mm. It was observed that workpiece surface quality get worse with the increase of feed rate or decrease of cutting speed. As a result of this work, it was seen that 128 m/min cutting speed and 0.16 mm/rev feed rate for the 2 mm cutting depth are the optimum cutting conditions from the point of surface quality.

  18. Tensile and Impact Properties of Shielded Metal Arc Welded AISI 409M Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    K.Shanmugam; A.K.Lakshminarayanan; V.Balasubramanian

    2009-01-01

    The present study is concerned with the effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the joints fabricated by austenitic stainless steel, ferritic stainless steel and duplex stainless steel filler metals were evaluated and the results were reported. From this investigation, it is found that the joints fabricated by duplex stainless steel filler metal showed higher tensile strength and hardness compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Joints fabricated by austenitic stainless steel filler metal exhibited higher ductility and impact toughness compared with the joints fabricated by ferritic stainless steel and duplex stainless steel filler metals.

  19. Stress corrosion cracking of AISI 321 stainless steel in acidic chloride solution

    Indian Academy of Sciences (India)

    Yanliang Huang

    2002-02-01

    The stress corrosion cracking (SCC) of AISI 321 stainless steel in acidic chloride solution was studied by slow strain rate (SSR) technique and fracture mechanics method. The fractured surface was characterized by cleavage fracture. In order to clarify the SCC mechanism, the effects of inhibitor KI on SCC behaviour were also included in this paper. A study showed that the inhibition effects of KI on SCC were mainly attributed to the anodic reaction of the corrosion process. The results of strain distribution in front of the crack tip of the fatigue pre-cracked plate specimens in air, in the blank solution (acidic chloride solution without inhibitor KI) and in the solution added with KI measured by speckle interferometry (SPI) support the unified mechanism of SCC and corrosion fatigue cracking (CFC).

  20. Effect of Plasma Nitriding Temperatures on Characteristics of Aisi 201 Austenitic Stainless Steel

    Science.gov (United States)

    Gao, Yuxin; Zheng, Shaomei

    2016-10-01

    Samples of AISI 201 austenitic stainless steel were produced by plasma nitriding at 350∘C, 390∘C, 420∘C, 450∘C and 480∘C for 5h. Systematic characterization of the nitrided layer was carried out in terms of micrograph observations, phase identification, chemical composition depth profiling, surface microhardness measurements and electrochemical corrosion tests. The results show that the surface hardness and the layer thickness increased with increasing temperature. XRD indicated that a single S-phase layer was formed during low temperature (≤420∘C), while Cr2N or CrN phase was formed besides S-phase when nitrided at 450∘C and 480∘C. The specimen treated at 390∘C presents a much enhanced corrosion resistance compared to the untreated substrate. The corrosion resistance deteriorated for samples treated above 450∘C due to the formation of chromium nitrides.

  1. Influence of nitrogen alloying on hydrogen embrittlement in AISI 304-type stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hannula, S.-P.; Hanninen, H.; Tahtinen, S.

    1984-12-01

    Hydrogen embrittlement of AISI 304-type austenitic stainless steels has been studied with special emphasis on the effects of the nitrogen content of the steels. Hydrogen charging was found to degrade the mechanical properties of all the steels studied, as measured by a tensile test. The fracture surfaces of hydrogen charged specimens were brittle cleavage-like whereas the uncharged specimens showed ductile, dimpled fracture. In sensitized materials transgranular cleavage mode of fracture was replaced by an intergranular mode of fracture and the losses of mechanical properties were higher. Nitrogen alloying decreased the hydrogen-induced losses of mechanical properties by increasing the stabilit of austenite. In sensitized steels the stability of austenite and nitrogen content were found to have only a minor effect on hydrogen embrittlement, except when sensitization had caused ..cap alpha..'-martensite transformation at the grain boundaries.

  2. Influence of nitrogen alloying on hydrogen embrittlement in AISI 304-type stainless steels

    Science.gov (United States)

    Hannula, Simo-Pekka; Hänninen, Hannu; Tähtinen, Seppo

    1984-12-01

    Hydrogen embrittlement of AISI 304-type austenitic stainless steels has been studied with special emphasis on the effects of the nitrogen content of the steels. Hydrogen charging was found to degrade the mechanical properties of all the steels studied, as measured by a tensile test. The fracture surfaces of hydrogen charged specimens were brittle cleavage-like whereas the uncharged specimens showed ductile, dimpled fracture. In sensitized materials transgranular cleavage mode of fracture was replaced by an intergranular mode of fracture and the losses of mechanical properties were higher. Nitrogen alloying decreased the hydrogen-induced losses of mechanical properties by increasing the stability of austenite. In sensitized steels the stability of austenite and nitrogen content were found to have only a minor effect on hydrogen embrittlement, except when sensitization had caused α'-martensite transformation at the grain boundaries.

  3. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.

    2005-01-01

    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  4. Surface characteristics analysis of dry EDMed AISI D2 steel using modified tool design

    Energy Technology Data Exchange (ETDEWEB)

    Pragadish, N.; Kumar, M. Pradeep [Anna University, Chennai (China)

    2015-04-15

    A modified tool design is proposed which helps in drilling holes without any central core, and also enables the effective removal of the debris particles. Experiments were conducted on AISI D2 Steel using copper electrode as tool in both conventional EDM and dry EDM processes and the performance of both processes is compared. Experiments were designed using Taguchi's L27 orthogonal array. Discharge current (I), gap voltage (V), pulse on time (T{sub ON}), gas pressure (P) and tool rotational speed (N) were chosen as the various input parameters, and their effect on the material removal rate (MRR), surface roughness (SR), surface morphology, microstructure and elemental composition of the machined surface is analyzed. The experimental results show better surface characteristics in the surface machined under dry EDM process.

  5. ANALYSIS OF CUTTING FORCE AND CHIP MORPHOLOGY DURING HARD TURNING OF AISI D2 STEEL

    Directory of Open Access Journals (Sweden)

    X. M. ANTHONY

    2015-03-01

    Full Text Available In this research work AISI D2 tool steel at a hardness of 55 HRC is being used for experimental investigation. Cutting speed, feed rate and depth of cut are the cutting parameters considered for the experimentation along with tool geometry namely, nose radius, clearance angle and rake angle. Three different cutting tool materials are used for experimentation namely multicoated carbide, cermet and ceramic inserts. The cutting force generated during the machining process is being measured using Kistler dynamometer and recorded for further evaluation. The chips produced during the machining process for every experimental trail is also collected for understanding the chip morphology. Based on the experimental data collected Analysis of Variance (ANOVA was conducted to understand the influence of all cutting parameters and tool geometry on cutting force.

  6. Determining Ms temperature on a AISI D2 cold work tool steel using magnetic Barkhausen noise

    Energy Technology Data Exchange (ETDEWEB)

    Huallpa, Edgar Apaza, E-mail: gared1@gmail.com [Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes 2463, 05508-030 SP (Brazil); Sánchez, J. Capó, E-mail: jcapo@usp.br [Departamento de Física, Facultad de Ciencias Naturales, Universidad de Oriente, Av. Patricio Lumumba s/n 90500, Santiago de Cuba (Cuba); Padovese, L.R., E-mail: lrpadove@usp.br [Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes 2463, 05508-030 SP (Brazil); Goldenstein, Hélio, E-mail: hgoldens@usp.br [Escola Politécnica da Universidade de São Paulo, Av. Prof. Mello Moraes 2463, 05508-030 SP (Brazil)

    2013-11-15

    Highlights: ► MBN was used to follow the martensite transformation in a tool steel. ► The results were compared with resistivity experiments. ► The Ms was estimated with Andrews equation coupled to ThermoCalc calculations. The experimental results showed good agreement. -- Abstract: The use of Magnetic Barkhausen Noise (MBN) as a experimental method for measuring the martensite start (Ms) temperature was explored, using as model system a cold-work tool steel (AISI D2) austenitized at a very high temperature (1473 K), so as to transform in sub-zero temperatures. The progress of the transformation was also followed with electrical resistance measurements, optical microscopy and scanning electron microscopy. Both MBN and resistivity measurements showed a change near 230 K during cooling, corresponding to the Ms temperature, as compared with 245 K, estimated with Andrews empirical equation applied to the austenite composition calculated using ThermoCalc.

  7. Evaluation of the corrosion resistance of AISI 316 stainless steel filters

    Directory of Open Access Journals (Sweden)

    Luzinete Pereira Barbosa

    2005-06-01

    Full Text Available In this investigation, the corrosion resistance of AISI 316 SS filters prepared with powders in the size ranges 74-44 µm and 210-105 µm and compacted with pressures of 300 MPa and 400 MPa has been evaluated in naturally aerated 0.5 M H2SO4 solution at 25 °C. Weight loss of filters manufactured with compacting pressure of 400 MPa were significantly higher than that of filters compacted at 300 MPa. The filter compacted at 400 MPa had higher carbon and nitrogen contents compared to those compacted at 300 MPa. The former also had chromium rich precipitates and oxides in the grain boundaries. The pores in filters compacted at 400 MPa were smaller than in filters compacted at 300 MPa. Smaller pores favor the formation of concentration cells and consequently, increased crevice corrosion.

  8. Dynamic fracture toughness and Charpy impact properties of an AISI 403 martensitic stainless steel

    Science.gov (United States)

    Sreenivasan, P. R.; Ray, S. K.; Mannan, S. L.; Rodriguez, P.

    1996-04-01

    Dynamic fracture toughness and Charpy impact properties of a normalised and tempered AISI 403 martensitic stainless steel obtained from instrumented impact tests are presented. Procedures for estimating dynamic fracture toughness ( KId) from the load-time traces obtained in instrumented tests of unprecracked Charpy V-notch (CVN) specimens are considered. The estimated KId values show reasonable agreement with those obtained from instrumented drop-weight and precracked Charpy tests. Also, except in the upper transition and uppershelf regions, the ASME KIR curve is generally conservative (i.e. gives lower KId values) when compared to the above KId estimates. The conservatism of the ASME KIR at the upper transition and uppershelf temperatures needs verification/validation. The lowest KId values estimated at the lower shelf temperatures for the above steel, namely, 33-42 MPa√m are in good agreement with the reported values of 35-50 MPa√m for the same steel in the literature.

  9. Martensitic Transformation during Fatigue Testing of an AISI 301LN Stainless Steel

    Science.gov (United States)

    Mateo, A.; Fargas, G.; Zapata, A.

    2012-02-01

    The plastic deformation accumulated during fatigue testing can induce the transformation of austenite to martensite in metastable austenitic stainless steels. To analyze this issue, a metastable austenitic stainless steel grade AISI 301 LN was studied in two different conditions, i.e. annealed and cold rolled. In the first case, the steel was fully austenitic, whereas cold rolled material had almost 30% of martensite. High cycle fatigue tests at a stress ratio of 0.8 were carried out on flat specimens from both steel conditions. Several characterization techniques, including optical microscopy, X-ray diffraction (XRD) and electron back scattered diffraction (EBSD), were used to detect and quantify the martensite induced by the cyclic deformation.

  10. Microstructure and Texture Evolutions in AISI 1050 Steel by Flow Forming

    Energy Technology Data Exchange (ETDEWEB)

    Bedekar, Vikram [Timken Technology Center, Canton, OH; Pauskar, Praveen [Ohio State University, Columbus; Shivpuri, Rajiv [Ohio State University, Columbus; Howe, Jane Y [ORNL

    2014-01-01

    Hot rolled and annealed AISI 1050 steel cylindrical coupons were flow formed at different levels of deformation (66% and 90% wall thickness reduction). TEM studies revealed development of ultra fine (sub) grain cell structure due to severe plastic deformation. The transverse subgrain size changed from 10 m (beginning) to 300nm (66% deformation) to 40nm (90% deformation). EBSD study revealed decreased recrystallization fraction at 90% deformation compared with 66% deformation due to orientation pinning from preferred orientation along {002} planes. No evidence of dislocation pinning or cracking was observed on any samples. The aim of the present work is to study the deformation behaviour and microstructural evolution during conventional flow forming process. The study also sheds light on the strengthening behaviour and structural changes during severe straining.

  11. Optimization of Process Parameters in Turning of AISI 8620 Steel Using Taguchi and Grey Taguchi Analysis

    Directory of Open Access Journals (Sweden)

    Sunil Kumar Sharma

    2014-03-01

    Full Text Available The aim of this research is to investigate the optimization of cutting parameters (cutting speed, feed rate and depth of cut for surface roughness and metal removal rate in turning of AISI 8620 steel using coated carbide insert. Experiments have been carried out based on Taguchi L9 standard orthogonal array design with three process parameters namely cutting speed, feed rate and depth of cut for surface roughness and metal removal rate. The objective function has been chosen in relation to surface roughness and metal removal rate for quality target. Optimal parameters contribution of the CNC turning operation was obtained via grey relational analysis. The analysis of variance is applied to identify the most significant factor. Experiment with the optimized parameter setting, which has been obtained from the analysis, are giving to validate the results.

  12. Nitrocarburizing of AISI-304 stainless steel using high-voltage plasma immersion ion implantation

    Science.gov (United States)

    Abd El-Rahman, A. M.; Mohamed, S. H.; Ahmed, M. R.; Richter, E.; Prokert, F.

    2009-05-01

    AISI-304 austenitic stainless steel has been nitrocarburized in N 2 and C 2H 2 ambient using high-voltage plasma immersion ion implantation (PIII) technology. The use of different PIII treatment times revealed important hints with respect to the microstructural, mechanical and corrosion properties of the nitrocarburized layer. Grazing incidence X-ray diffraction (GIXRD) shows the presence of nitride ( γN and CrN) and carbide ( γC and Fe 3C) phases. Glow discharge optical spectroscopy (GDOS) has been used to characterize the elemental depth profiles in which the thickness of the modified layers is derived. Dynamic microindentation method is used for the study of mechanical performance of the nitrocarburized layer as well as the untreated material. The microhardness has been increased to a maximum value of more than nine times compared to that of the untreated one. The corrosion performance is characterized by potentiodynamic polarization technique and was found to be treatment time dependent.

  13. Variación microestructural del acero AISI 1045 endurecido por rodadura

    Directory of Open Access Journals (Sweden)

    Esther Fernández-Guilarte

    2010-03-01

    Full Text Available En este trabajo se analiza el comportamiento microestructural del acero AISI 1045, endurecido mediante deformación plástica superficial por rodillo, empleando como variables en el proceso de endurecimiento el número de revoluciones, avance y fuerza del torno 16D20. Se empleó el análisis espectral para determinar la composición química del acero y el Nital como reactivo químico para resaltar la estructura metalográfica después de pulida. Se establecen los parámetros de los regímenes de la deformación plástica superficial por rodillo para evaluar la dureza de los pasadores utilizados en las esteras de los equipos de laboreo minero y se expone una metodología para determinar el tiempo de ejecución del corte de las muestras.

  14. Fatigue assessment by energy approach during tensile tests on AISI 304 steel

    Directory of Open Access Journals (Sweden)

    A. Risitano

    2017-01-01

    Full Text Available Estimation of the fatigue limit for steel ductile materials using non-destructive methods is a topic of great interest to researchers today. In recent years, the method adopted has implemented infrared sensors to detect the surface temperature and correlate it with the fatigue limit. In previous paper, a new energy approach was proposed to investigate the fatigue limit during tensile test. The numerical procedure proposed by Chrysochoos is adopted to clean infrared images and applied to analyse the surface heat sources during tensile test. AISI 304 specimens with rectangular cross-sections are tested. Moreover fatigue tests at increasing loads were carried out on steel by a stepwise succession, applied to the same specimen, for applying the thermographic method. The predictions of the fatigue limit, obtained by the analysis of the energy evolution during the static tests, were compared with the predictions obtained applying the thermographic method during fatigue tests.

  15. Effect of Hydrogen and Strain-Induced Martensite on Mechanical Properties of AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Sang Hwan Bak

    2016-07-01

    Full Text Available Plastic deformation and strain-induced martensite (SIM, α′ transformation in metastable austenitic AISI 304 stainless steel were investigated through room temperature tensile tests at strain rates ranging from 2 × 10−6 to 2 × 10−2/s. The amount of SIM was measured on the fractured tensile specimens using a feritscope and magnetic force microscope. Elongation to fracture, tensile strength, hardness, and the amount of SIM increased with decreasing the strain rate. The strain-rate dependence of RT tensile properties was observed to be related to the amount of SIM. Specifically, SIM formed during tensile tests was beneficial in increasing the elongation to fracture, hardness, and tensile strength. Hydrogen suppressed the SIM formation, leading to hydrogen softening and localized brittle fracture.

  16. Effect of Carbon and Nitrogen Content on Deformation and Fracture of AISI 304 Austenitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    C. Menapace

    2008-04-01

    Full Text Available The effect of small differences in the content of carbon and nitrogen on the room temperature tensile deformation and fracture behaviour of an AISI 304 stainless steel was studied. In the steel containing the lower amount of carbon and nitrogen, a higher amount of strain induced alfa’ martensite is formed, which increases strain hardening rate and both uniform and total elongation at fracture. The presence of large martensitic areas in the cross section causes strain localization at the austenite/martensite interface, which promotes the nucleation of cracks and their propagation along the interface. This results in a decrease of Ultimate Tensile Strength. Strain induced transformation slightly reduces strain rate sensitivity, as well.

  17. Surface Modification by Nitrogen Plasma Immersion Ion Implantation on Austenitic AISI 304 Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Miguel CASTRO-COLIN; William DURRER; Jorge ALPEZ; Enrique RAMIREZ-HOMS

    2016-01-01

    Surfaces of AISI 304 austenitic stainless steel plates nitrided by plasma immersion ion implantation (PIII) technology were studied by means of Auger electron spectroscopy (AES)and X-ray photoelectron spectroscopy (XPS)to determine the effect of the nitriding process on the surface and subjacent layers.Elemental compositions obtained by AES and XPS at varying depths indicate that the saturation of N is relatively constant as a function of depth,indicating the reliability of PIII technology for subsurface saturation.It is concluded that the concentrations of both Cr and O increase with depth,the subjacent oxide is driven by the Ar+ sputtering process used to access the lower layers,and then N is bound to Cr.

  18. Adhesion of composite carbon/hydroxyapatite coatings on AISI 316L medical steel

    Directory of Open Access Journals (Sweden)

    J. Gawroński

    2009-07-01

    Full Text Available In this paper are contains the results of studies concerning the problems associated with increased of hydroxyapatite (HAp adhesion, manufactured by using Pulse Laser Deposition (PLD method, to the austenitic steel (AISI 316L through the coating of carbon interlayer on it. Carbon coating was deposited by Radio Frequency Plasma Assisted Chemical Vapour Deposition (RF PACVD method.Test results unequivocally showed that the intermediate carbon layer in a determined manner increase the adhesion of hydroxyapatite to the metallic substrate. Obtained results give rise to deal with issues of manufacturing composite bilayer – carbon film/HAp – on ready implants, casted from austenitic cast steel by lost-wax process method as well as in gypsum forms.

  19. Analysis of deformation induced martensite in AISI 316L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Jagarinec, Darko; Kirbis, Peter; Predan, Jozef; Vuherer, Tomaz; Gubeljak, Nenad [Maribor Univ. (Slovenia). Faculty of Mechanical Engineering

    2016-08-01

    Metastable austenite stainless steel AISI 316L is sensitive to cold deformation, where transformation from austenite to martensite occurred. The bending deformation as the formation process leads to tensile and compression throughout the thickness of the billet. Tensile testing of the specimen causes differences in the true stress-strain along the contraction neck prior to fracture as well. The aim of the paper is to find correlation between microhardness as brief inspection parameters and extension of martensitic transformation. The total equivalent plastic strain extend diagram obtained by numerical simulation of bending was compared with tensile true stress-strain diagram. Results show very good correlation between hardness, true strain and martesite content. Therefore, one can conclude that by hardness measurement, it is possible to measure the level of equivalent plastic strain until ultimate tensile stress as a linear correlation between hardness, true strain and martesite content.

  20. An investigation of the aseptic loosening of an AISI 316L stainless steel hip prosthesis.

    Science.gov (United States)

    Godec, Matjaz; Kocijan, Aleksandra; Dolinar, Drago; Mandrino, Djordje; Jenko, Monika; Antolic, Vane

    2010-08-01

    The total replacement of joints by the implantation of permanently indwelling prosthetic components has been one of the major successes of modern surgery in terms of relieving pain and correcting deformity. However, the aseptic loosening of a prosthetic-joint component is the most common reason for joint-revision surgery. Furthermore, it is thought that wear particles are one of the major contributors to the development and perpetuation of aseptic loosening. The aim of the present study was to identify the factors related to the aseptic loosening of an AISI 316L stainless steel total hip prosthesis. The stem was evaluated by x-ray photoelectron spectroscopy, with polished and rough regions being analyzed in order to establish the differences in the chemical compositions of both regions. Specific areas were examined using scanning electron microscopy with energy dispersive x-ray spectroscopy and light microscopy.

  1. Active flux tungsten inert gas welding of austenitic stainless steel AISI 304

    Directory of Open Access Journals (Sweden)

    D. Klobčar

    2016-10-01

    Full Text Available The paper presents the effects of flux assisted tungsten inert gas (A-TIG welding of 4 (10 mm thick austenitic stainless steel EN X5CrNi1810 (AISI 304 in the butt joint. The sample dimensions were 300 ´ 50 mm, and commercially available active flux QuickTIG was used for testing. In the planned study the influence of welding position and weld groove shape was analysed based on the penetration depth. A comparison of microstructure formation, grain size and ferrit number between TIG welding and A-TIG welding was done. The A-TIG welds were subjected to bending test. A comparative study of TIG and A-TIG welding shows that A-TIG welding increases the weld penetration depth.

  2. Electrochemical behaviour of iron and AISI 304 stainless steel in simulated acid rain solution

    Energy Technology Data Exchange (ETDEWEB)

    Pilic, Zora; Martinovic, Ivana [Mostar Univ. (Bosnia and Herzegovina). Dept. of Chemistry

    2016-10-15

    The growth mechanism and properties of the oxide films on iron and AISI 304 stainless steel were studied in simulated acid rain (pH 4.5) by means of electrochemical techniques and atomic absorption spectrometry. The layer-pore resistance model was applied to explain a potentiodynamic formation of surface oxides. It was found that the growth of the oxide film on iron takes place by the low-field migration mechanism, while that on the stainless steel takes place by the high-field mechanism. Kinetic parameters were determined. Impedance measurements revealed that Fe surface film has no protective properties at the open circuit potential, while the resistance of stainless steel oxide film is very high. The concentration of the metallic ions released into solution and measured by atomic absorption spectroscopy was in accordance with the results obtained from the electrochemical techniques.

  3. Influence of Laser Peening on Phase Transformation and Corrosion Resistance of AISI 321 steel

    Science.gov (United States)

    Karthik, D.; Swaroop, S.

    2016-07-01

    The objective of this study is to investigate the influence of laser peening without coating (LPwC) on austenitic to martensitic (γ → α') phase transformation and corrosion behavior of austenitic stainless steel AISI 321 in 3.5% NaCl environment. Results indicate that LPwC induces a large compressive residual stresses of nearly -854 MPa and γ → α' phase transformation of about 18% (volume fraction). Microstructures of peened surface confirmed the γ → α' phase transformation and showed no grain refinement. Hardness increased slightly with a case depth of 900 μm. Despite the smaller surface roughness introduced, corrosion resistance improved after peening due to compressive residual stresses.

  4. Microstructure and Hardness of High Temperature Gas Nitrided AISI 420 Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Ibrahim Nor Nurulhuda Md.

    2014-07-01

    Full Text Available This study examined the microstructure and hardness of as-received and nitrided AISI 420 martensitic stainless steels. High temperature gas nitriding was employed to treat the steels at 1200°C for one hour and four hours using nitrogen gas, followed by furnace cooled. Chromium nitride and iron nitride were formed and concentrated at the outmost surface area of the steels since this region contained the highest concentration of nitrogen. The grain size enlarged at the interior region of the nitrided steels due to nitriding at temperature above the recrystallization temperature of the steel and followed by slow cooling. The nitrided steels produced higher surface hardness compared to as-received steel due to the presence of nitrogen and the precipitation of nitrides. Harder steel was produced when nitriding at four hours compared to one hour since more nitrogen permeated into the steel.

  5. Acoustic Emission Methodology to Evaluate the Fracture Toughness in Heat Treated AISI D2 Tool Steel

    Science.gov (United States)

    Mostafavi, Sajad; Fotouhi, Mohamad; Motasemi, Abed; Ahmadi, Mehdi; Sindi, Cevat Teymuri

    2012-10-01

    In this article, fracture toughness behavior of tool steel was investigated using Acoustic Emission (AE) monitoring. Fracture toughness ( K IC) values of a specific tool steel was determined by applying various approaches based on conventional AE parameters, such as Acoustic Emission Cumulative Count (AECC), Acoustic Emission Energy Rate (AEER), and the combination of mechanical characteristics and AE information called sentry function. The critical fracture toughness values during crack propagation were achieved by means of relationship between the integral of the sentry function and cumulative fracture toughness (KICUM). Specimens were selected from AISI D2 cold-work tool steel and were heat treated at four different tempering conditions (300, 450, 525, and 575 °C). The results achieved through AE approaches were then compared with a methodology proposed by compact specimen testing according to ASTM standard E399. It was concluded that AE information was an efficient method to investigate fracture characteristics.

  6. On The Enhancement of Wear Resistance of Hardened Carbon Tool Steel (AISI 1095) With Cryogenic Quenching

    Institute of Scientific and Technical Information of China (English)

    V.Soundararajan; N.Alagurmurthi; K.Palaniradja

    2004-01-01

    Many experimental investigations reveal that it is very difficult to have a completely martensitic structure by any hardening process. Some amount of austenite is generally present in the hardened steel. This austenite existing along with martensite is normally referred as the retained austenite. The presence of retained austenite greatly reduces the mechanical properties and such steels do not develop maximum hardness even after cooling at rates higher than the critical cooling rates.Strength can be improved in hardened steels containing retained austenite by a process known as cryogenic quenching.Untransformed austenite is converted into martensite by this treatment. This conversion of retained austenite into martensite results in increased hardness, wear resistance and dimensional stability of steel. Wear can be defined as the progressive loss of materials from the operating surface of a body occurring as a result of relative motion at the surface. Hardness, load,speed, surface roughness, temperature are the major factors which influences wear. Many studies on wear indicate that increasing hardness decreases the wear of a material. With this in mind, to study the surface wear on a surface modified(Cryogenic treated) steel material an attempt has been made in this paper. In this study as a Part -I Hardening was carried out on carbon tool steel (AISI 1095) of different L/D ratio with conventional quenchants like purified water, aqueous solution and Hot mineral oil. As a Part -Ⅱ hardening was followed by quenching was carried out as said in Part- I and the hardened specimen were quenched in liquid Nitrogen which is at sub zero condition. The specimens were tested for its microstructure, hardness and wear loss. The results were compared and analyzed. The alloying elements increases the content of retained austenite hence the material used was AISI1095 (Carbon 0.9%, Si 0.2%, Mn0.4% and the rest Iron)

  7. Effect of the purging gas on properties of Ti stabilized AISI 321 stainless steel TIG welds

    Energy Technology Data Exchange (ETDEWEB)

    Taban, Emel; Kaluc, Erdinc; Aykan, T. Serkan [Kocaeli Univ. (Turkey). Dept. of Mechanical Engineering

    2014-07-01

    Gas purging is necessary to provide a high quality of stainless steel pipe welding in order to prevent oxidation of the weld zone inside the pipe. AISI 321 stabilized austenitic stainless steel pipes commonly preferred in refinery applications have been welded by the TIG welding process both with and without the use of purging gas. As purging gases, Ar, N{sub 2}, Ar + N{sub 2} and N{sub 2} + 10% H{sub 2} were used, respectively. The aim of this investigation is to detect the effect of purging gas on the weld joint properties such as microstructure, corrosion, strength and impact toughness. Macro sections and microstructures of the welds were investigated. Chemical composition analysis to obtain the nitrogen, oxygen and hydrogen content of the weld root was done by Leco analysis. Ferrite content of the beads including root and cap passes were measured by a ferritscope. Vickers hardness (HV10) values were obtained. Intergranular and pitting corrosion tests were applied to determine the corrosion resistance of all welds. Type of the purging gas affected pitting corrosion properties as well as the ferrite content and nitrogen, oxygen and hydrogen contents at the roots of the welds. Any hot cracking problems are not predicted as the weld still solidifies with ferrite in the primary phase as confirmed by microstructural and ferrite content analysis. Mechanical testing showed no significant change according to the purge gas. AISI 321 steel and 347 consumable compositions would permit use of nitrogen rich gases for root shielding without a risk of hot cracking.

  8. Investigating the correlation between some of the properties of plasma nitrided AISI 316L stainless steel

    Directory of Open Access Journals (Sweden)

    M. Olzon-Dionysio

    2013-01-01

    Full Text Available When AISI 316L stainless steels are submitted to the nitriding process at temperatures lower than 450 °C, a high nitrogen content expanded austenite phase is formed, which shows higher hardness and higher pitting corrosion resistance compared to the untreated material. As a result, this material becomes adequate for biomedical application. The conditions of the nitriding technique, such as gas mixture, pressure, time and temperature, play an important role in some properties of the modified layer, including: thickness, hardness and N concentration along the layer. This paper explores a set of six samples of AISI 316L, nitrided at different times and temperatures, whose properties show important differences. The aim of this research is to investigate the correlation between the nitrided layer thickness (in the range of 0.77 to 11 µm with both X-ray patterns characteristics and hardness measurements, which used two distinct loads. The results of this study show that: whereas the 3.6 gf load was suitable to measure the real hardness for four of the nitrided layers showing thickness ≥ 2.9 µm, the 50 gf load measured a substrate contribution, probably even for the highest thickness, 11 µm. Moreover, analyzing different reflections of the X-ray patterns showed evidence of the clear consistency between the X-Ray depths and the nitrided layer thicknesses: if the layer thickness is lower than the penetration depth of X-rays, two phases (austenite and expanded substrate are present. If the layer thickness is higher, only the austenite is observed. Finally, concerning the citotoxicity property, all the samples, nitrided or not, were approved in the test for biocompatibility, indicating their potential use for biomedical applications.

  9. Tribological Properties of Nanometric Atomic Layer Depositions Applied on AISI 420 Stainless Steel

    Directory of Open Access Journals (Sweden)

    E. Marin

    2013-09-01

    Full Text Available Atomic Layer Deposition ( ALD is a modern technique that Allows to deposit nanometric, conformal coatings on almost any kind of substrates, from plastics to ceramic, metals or even composites. ALD coatings are not dependent on the morphology of the substrate and are only regulated by the composition of the precursors, the chamber temperature and the number of cycles. In this work, mono- and bi -layer nanometric, protective low-temperature ALD Coatings, based on Al2O3 and TiO2 were applied on AISI 420 Stainless Steel in orderto enhance its relatively low corrosion resistance in chloride containing environments. Tribological testing were also performed on the ALD coated AISI 420 in order to evaluate the wear and scratch resistance of these nanometric layers and thus evaluate their durability. Scratch tests were performed using a standard Rockwell C indenter, under a variable load condition, in order to evaluate the critical loading condition for each coating. Wear testing were performed using a stainless steel counterpart, in ball-on-discconfiguration, in order to measure the friction coefficient and wear to confront the resistance. All scratch tests scars and wear tracks were then observed by means of Scanning Electron Microscopy (SEM in order to understand the wear mechanisms that occurred on the sample surfaces. Corrosion testing, performed under immersion in 0.2 M NaCl solutions, clearly showed that the ALD coatings have a strong effect in protecting the Stainless Steel Substrate against corrosion, reducing the corrosion current density by two orders of magnitude.Tribological The preliminary results showed that ALD depositions obtained at low Temperatures have a brittle behavior caused by the amorphous nature of their structure, and thus undergo delamination phenomena during Scratch Testing at relatively low applied loads. During ball-on-disc testing, the coatings were removed from the substrate, in particular for monolayer ALD configurations

  10. Problemas en la reparación por laser cladding de superficies de acero AISI D2 tratado térmicamente

    Directory of Open Access Journals (Sweden)

    Busquets, D.

    2010-08-01

    microscopia óptica, microscopía electrónica de barrido (MEB y difracción de electrones retrodispersados (EBSD. El objetivo del trabajo es relacionar los parámetros del proceso de recubrimiento por láser (potencia, velocidad, caudal de polvo con las transformaciones metalúrgicas producidas en el acero de herramienta AISI D2, con el fin de optimizar las condiciones de operación durante la reparación. Los resultados muestran que los parámetros influyen en gran medida en la geometría del cordón y en la formación de la microestructura. Aunque es sencillo obtener deposiciones geométricamente aceptables (forma y tamaño adecuado, ausencia de porosidad, en muchos casos aparecen fenómenos perjudiciales como la dilución de carburos y la aparición de fases metaestables que modifican las propiedades mecánicas del recubrimiento. En concreto, la presencia de austenita retenida en el recubrimiento, relacionada con la temperatura máxima alcanzada y la velocidad de enfriamiento, produce una fuerte disminución en la dureza, que debe evitarse. Además, para una misma composición y acabado superficial, el estado metalúrgico inicial del sustrato tiene una gran influencia sobre el resultado. Sustratos en estado de temple implican una mayor absorción del láser y la acumulación de calor que produce mayores zonas afectadas por el calor (ZAC. Por ese motivo, deben optimizarse los parámetros del proceso para cada operación de manera que se mejore el comportamiento en servicio del componente.

  11. Relaciones cuantitativas entre los contenidos de azufre y de sulfuros en los aceros inoxidables tipo AISI 303: influencia de la composición química de los sulfuros

    Directory of Open Access Journals (Sweden)

    Botella, J.

    1999-06-01

    Full Text Available The work has been done with ten AISI 303 stainless steel rods which have similar chemical compositions, except for sulphur which varies between 0.25 and 0.36%. These steels are studied by Scanning Electron Microscopy (SEM and Energy Dispersive X-Ray Spectrometry (EDX. The sulphides are chemically microanalysed and the occupied volume determined by automatic image analysis. It can be inferred that the chemical composition of sulphides in AISI 303 steels is variable to some extent even though the steel chemistry is almost invariable. This could mean that solidification conditions and thermomechanical transformations are able to affect resulting in variations of sulphide compositions. Quantitative relations between sulphur and sulphide contents are established and the influence of sulphide chemical compositions on those relations is studied. The experimental results are compared with those obtained from theoretical calculations. A good approach is obtained when the difference between chemical compositions of real sulphides and the theoretical one, MnS, is taken into account.

    Se trabaja con una serie de diez redondos de aceros inoxidables tipo AISI 303 de composiciones químicas prácticamente iguales a excepción del azufre que varía entre 0,25 y 0,36%. Se examinan los aceros mediante Microscopía Electrónica de Barrido (MEB y Espectrometría de Dispersión de Energías de Rayos X (EDX acoplada al MEB, analizándose químicamente los sulfuros y determinando, mediante análisis automático de imágenes, los volúmenes ocupados por los sulfuros. Parece deducible que la composición química de los sulfuros en el AISI 303 puede ser discretamente variable aún siendo prácticamente invariable la composición química del acero. Ello podría significar que las condiciones de solidificación y las transformaciones termomecánicas pueden influir, dando como resultado variaciones en la composición química de los sulfuros. Se establecen

  12. Study of corrosion resistance of AISI 444 ferritic stainless steel for application as a biomaterial; Estudo da resistencia a corrosao do aco inoxidavel ferritico AISI 444 para aplicacao como biomaterial

    Energy Technology Data Exchange (ETDEWEB)

    Marques, Rogerio Albuquerque

    2014-09-01

    Ferritic stainless steels are ferromagnetic materials. This property does not allow their use in orthopedic prosthesis. Nevertheless, in some specific applications, this characteristic is very useful, such as, for fixing dental and facial prostheses by using magnetic attachments. In this study, the corrosion resistance and cytotoxicity of the AISI 444 ferritic stainless steel, with low nickel content, extra-low interstitial levels (C and N) and Ti and Nb stabilizers, were investigated for magnetic dental attachments application. The ISO 5832-1 (ASTM F-139) austenitic stainless steel and a commercial universal keeper for dental attachment (Neo-magnet System) were evaluated for comparison reasons. The first stainless steel is the most used metallic material for prostheses, and the second one, is a ferromagnetic keeper for dental prostheses (NeoM). In vitro cytotoxicity analysis was performed by the red neutral incorporation method. The results showed that the AISI 444 stainless steel is non cytotoxic. The corrosion resistance was studied by anodic polarization methods and electrochemical impedance spectroscopy (EIS), in a saline phosphate buffered solution (PBS) at 37 °C. The electronic properties of the passive film formed on AISI 444 SS were evaluated by the Mott-Schottky approach. All tested materials showed passivity in the PBS medium and the passive oxide film presented a duplex nature. The highest susceptibility to pitting corrosion was associated to the NeoM SS. This steel was also associated to the highest dopant concentration. The comparatively low levels of chromium (nearly 12.5%) and molybdenum (0.3%) of NeoM relatively to the other studied stainless steels are the probable cause of its lower corrosion resistance. The NeoM chemical composition does not match that of the SUS444 standards. The AISI 444 SS pitting resistance was equivalent to the ISO 5832-1 pointing out that it is a potential candidate for replacement of commercial ferromagnetic alloys used

  13. Efecto de la modificación superficial de alambres delgados de acero inoxidable AISI 302 mediante plasma electrolítico sobre sus propiedades mecánicas

    Directory of Open Access Journals (Sweden)

    Gallegos, A.

    2012-12-01

    Full Text Available In this work different tests using electrolytic plasma (EP on thin wires of stainless steel AISI 302 in an inert solution were performed. Tensile tests were carried out in order to measure changes in the mechanical strength of the samples; moreover, both the morphological and microstructural changes also were evaluated. It was found that after 10 s of the application of EP, the samples surface was uniformly covered by nodules-like and craters similar to those found in the melting and cooling periods of EP. The results show a significant surface grain refinement, leading to crystalline arrangements with sizes less than 200 nm and also an increase in the samples tensile strength of at least 57 % respect to steel base.

    En este trabajo se realizaron ensayos de aplicación de plasma electrolítico (PE sobre alambres delgados de acero inoxidable AISI 302 en una solución inerte. Las probetas se sometieron a ensayos de tracción, con el fin de medir cambios en su resistencia mecánica; adicionalmente fueron evaluadas en sus cambios morfológicos y microestructurales. Se encontró que después de 10 s de aplicación de PE, la superficie de las probetas estaba uniformemente cubierta por nódulos y cráteres propios del ciclo de fusión y enfriamiento del PE; se evidenció un significativo afinamiento del grano superficial, llegando a ordenamientos cristalinos de tamaño menor a 200 nm y también se observó que la capa superficial afectada presentó un incremento de la resistencia a la tracción de al menos un 57 % respecto al acero base.

  14. Evaluación de la corrosión del acero AISI-SAE 1020 en un ambiente multifásico de salmuera CO2-H2S

    Directory of Open Access Journals (Sweden)

    Darío Yesid Peña Ballesteros

    2010-01-01

    Full Text Available La corrosión por CO2/H2S en la producción de gas y petróleo es una de las áreas de investigación más importantes, debido a la necesidad de evaluar la severidad de la corrosión, disminuir el riesgo de problemas en operación y además bajar los costos de producción. En Colombia, las investigaciones se orientan hacia la corrosión por CO2, a pesar de la existencia de trazas de H2S, que son un peligro potencial para los materiales de las líneas de transporte de hidrocarburos. En este artículo se analiza la experimentación y los resultados del acero expuesto a un sistema Salmuera/CO2/H2S en un cilindro rotatorio. En esta geometría se determinaron las velocidades de corrosión sobre el acero AISI 1020, así como los coeficientes de transferencia de masa y capas viscosas de las especies más representativas del sistema. Adicionalmente, se caracterizó la morfología de los productos de corrosión formados en estos ambientes. El estudio permitió concluir que las especies relacionadas con el CO2 (H2CO3 son las que influyen sobre el mecanismo de deterioro del acero AISI 1020, que está fuertemente influenciado por la variación de la velocidad, la temperatura y el pH.

  15. EFFECTS OF CARBURIZING AND NITRIDING PROCESSES ON THE COST AND QUALITY OF GEARS PRODUCED WITH AISI 4140 AND 8620 STEELS

    Directory of Open Access Journals (Sweden)

    Claudio José Leitão

    2012-09-01

    Full Text Available This study compares the effects of nitriding and carburizing processes applied to gears subjected to contact stresses below 1300 MPa. The manufacturing cost, as well the depth of hardened layer and the distortion produced by two processes are analyzed. AISI 4140 gears quenched, tempered, liquid and gas nitriding and AISI 8620 gears after liquid carburizing, quenching and tempering are analyzed. The dimensional control of the gears was carried out before and after heat and thermochemical treatments. It is concluded that liquid or gas nitriding processes are about 30% more economical than liquid carburizing an also they reduce the dimensional changes. By the other hand liquid carburizing achieves greater case depth. Liquid nitriding process presents the lowest cost, dimensional changes and case depth.

  16. OPTIMIZATION OF SURFACE ROUGHNESS AND TOOL FLANK WEAR IN TURNING OF AISI 304 AUSTENITIC STAINLESS STEEL WITH CVD COATED TOOL

    Directory of Open Access Journals (Sweden)

    M. KALADHAR

    2013-04-01

    Full Text Available AISI 304 austenitic stainless steel is a popularly used grade in the various fields of manufacturing because of its high ductility, high durability and excellent corrosion resistance. High work hardening, low heat conductivity and high built up edge (BUE formation made this as difficult-to- machine material. Poor surface quality and rapid tool wear are the common problems encountered while machining it. In the present work, an attempt has been made to explore the influence of machining parameters on the performance measures, surface roughness and flank wear in turning of AISI 304 austenitic stainless steel with a two layer Chemical vapour deposition(CVD coated tool. In order to achieve this, Taguchi approach has been employed. The results revealed that the cutting speed most significantly, influences both surface roughness and flank wear. In addition to this the optimal setting of process parameters and optimal ranges of performance measures are predicted.

  17. OPTIMIZATION OF SURFACE ROUGHNESS OF AISI 304 AUSTENITIC STAINLESS STEEL IN DRY TURNING OPERATION USING TAGUCHI DESIGN METHOD

    Directory of Open Access Journals (Sweden)

    D. PHILIP SELVARAJ

    2010-09-01

    Full Text Available The present work is concentrated with the dry turning of AISI 304 Austenitic Stainless Steel (ASS. This paper presents the influence of cutting parameters like cutting speed, feed rate and depth of cut on the surface roughness of austenitic stainless steel during dry turning. A plan of experiments based on Taguchi’s technique has been used to acquire the data. An orthogonal array, the signal to noise (S/N ratio and the analysis of variance (ANOVA are employed to investigate the cutting characteristics of AISI 304 austenitic stainless steel bars using TiC and TiCN coated tungsten carbide cutting tool. Finally the confirmation tests that have been carried out to compare the predicted values with the experimental values confirm its effectiveness in the analysis of surface roughness.

  18. LaCrO3 composite coatings for AISI 444 stainless steel solid oxide fuel cell interconnects

    Directory of Open Access Journals (Sweden)

    Wilson Acchar

    2012-12-01

    Full Text Available Doped lanthanum chromite-based ceramics are the most widely used interconnector material in solid fuel cells (SOFC since they exhibit significant electrical and thermal conductivity, substantial corrosion resistance and adequate mechanical strength at ambient and high temperatures. The disadvantage of this material is its high cost and poor ductility. The aim of this study is to determine the mechanical and oxidation behavior of a stainless steel (AISI 444 with a LaCrO3 deposition on its surface obtained through spray pyrolisis. Coated and pure AISI 444 materials were characterized by mechanical properties, oxidation behavior, X-ray diffraction and scanning electronic microscopy. Results indicated that the coated material displays better oxidation behavior in comparison to pure stainless steel, but no improvement in mechanical strength. Both materials indicate that deformation behavior depends on testing temperatures.

  19. Design of Quenching Process for Large-sized AISI P20 Steel Block Used as Plastic Die

    Institute of Scientific and Technical Information of China (English)

    Dongli SONG; Jianfeng GU; Jiansheng PAN; Xin YAO

    2006-01-01

    For large-sized AISI P20 steel block used as plastic die with a thickness of more than 200 mm, appropriate quenching processes are the key to obtain much thick hardened layer. In this paper, different quenching processes of AISI P20 steel block such as oil quenching, direct water quenching, water quenching with precooling and water quenching with pre-cooling and self-tempering were numerically investigated by computer simulation based on the detailed discussion on the mathematical models of quenching processes including partial differential equations of heat transfer, thermal physical properties, latent heat, heat transfer coefficient and calculation of phase transformation, The results show that the water quenching with pre-cooling and self-tempering process can not only effectively avoid quenching cracks, but also obtain deeper harden depth than oil quenching.

  20. Texture analysis of deformation induced martensite in an AISI 301L stainless steel: microtexture and macrotexture aspects

    OpenAIRE

    Hamilton Ferreira Gomes de Abreu; Marcelo José Gomes da Silva; Luís Flávio Gaspar Herculano; Harry Bhadeshia

    2009-01-01

    Experiments have been conducted to study the strain induced transformation from austenite to martensite in a metastable AISI 301LN austenitic stainless steel, deformed by uniaxial tension applied along rolling direction. Samples deformed 10 and 20% have shown the presence of α´ martensite phase. Measured pole figures of martensite phase were compared to calculated ones, assuming no variant selection and selection of variants where interaction between stress and the plate of martensite ad...

  1. In-situ investigation of martensite formation in AISI 52100 bearing steel at sub-zero Celsius temperature

    DEFF Research Database (Denmark)

    Villa, Matteo; Hansen, Mikkel Fougt; Pantleon, Karen;

    2013-01-01

    Martensite formation in AISI 52100 bearing steel at sub-zero Celsius temperature was investigated with Vibrating Sample Magnetometry. The investigation reports the stabilization of retained austenite in quenched samples during storage at room temperature and reveals the thermally activated nature...... of the martensitic transformation. The kinetics of the transformation is interpreted in terms of a-thermal nucleation and thermally activated growth of lenticular martensite....

  2. Wear and Adhesive Failure of Al2O3 Powder Coating Sprayed onto AISI H13 Tool Steel Substrate

    Science.gov (United States)

    Amanov, Auezhan; Pyun, Young-Sik

    2016-07-01

    In this study, an alumina (Al2O3) ceramic powder was sprayed onto an AISI H13 hot-work tool steel substrate that was subjected to sanding and ultrasonic nanocrystalline surface modification (UNSM) treatment processes. The significance of the UNSM technique on the adhesive failure of the Al2O3 coating and on the hardness of the substrate was investigated. The adhesive failure of the coating sprayed onto sanded and UNSM-treated substrates was investigated by a micro-scratch tester at an incremental load. It was found, based on the obtained results, that the coating sprayed onto the UNSM-treated substrate exhibited a better resistance to adhesive failure in comparison with that of the coating sprayed onto the sanded substrate. Dry friction and wear property of the coatings sprayed onto the sanded and UNSM-treated substrates were assessed by means of a ball-on-disk tribometer against an AISI 52100 steel ball. It was demonstrated that the UNSM technique controllably improved the adhesive failure of the Al2O3 coating, where the critical load was improved by about 31%. Thus, it is expected that the application of the UNSM technique to an AISI H13 tool steel substrate prior to coating may delay the adhesive failure and improve the sticking between the coating and the substrate thanks to the modified and hardened surface.

  3. A Comparative Analysis of Surface Roughness and Material Removal Rate in Milling Operation of AISI 410 Steel And Aluminium 6061

    Directory of Open Access Journals (Sweden)

    Gaurav Kumar,

    2014-06-01

    Full Text Available Surface roughness is an important measure of product quality since it greatly influences the performance of Mechanical parts as well as production cost. Roughness plays an extensive role in demonstrating how the object will interface with the environment. The main purpose of this paper is to analyse the comparative study of Surface Roughness and Material Removal Rate (MRR of Aluminium 6061and AISI 410 Steel. In the present paper three parameters were taken to check whether quality lies within desired tolerance level. Surface roughness and MRR were taken using three different parameters of CNC machining including spindle speed, feed rate and depth of cut. Optimization of surface roughness of aluminium 6061 and AISI 410 Steel were done using Response Surface Methodology. Response Surface Methodology is an adequate channel in which response variable can be optimized by taking several experimental runs. This paper aims to obtain an optimal setting of three milling parameters by using Carbide cutting tool in end milling operation of AISI 410 steel and Aluminium Alloy 6061 taken as specimen.

  4. Efecto de la adición de cobre y estaño en el comportamiento a la corrosión por picadura del acero inoxidable AISI 304

    Directory of Open Access Journals (Sweden)

    Pardo, A.

    2004-10-01

    Full Text Available The influence of copper and tin addition on the pitting corrosion resistance of AISI 304 stainless steel in 3.5 % NaCl at 20 °C has been studied using potenciodinamic and cyclic polarization. From that study the effect of alloying elements (Cu and Sn in the corrosion, pitting and repassivation potentials were determined. The effect of copper and tin on the critical pitting temperature (CPT was determined by icon-time-temperature curves. The influence of these alloying elements in FeCl3 under ASTM G48-00 norm was also studied. The addition of copper favours the nucleation of pits. The addition of tin slightly improves the corrosion resistance. The synergic effect of Cu-Sn was positive at low concentrations.

    Se estudia la influencia de la adición de cobre y estaño en la resistencia a la corrosión por picadura del acero inoxidable AISI 304, en 3,5 % NaCl a 20 °C mediante medidas potenciodinámicas de polarización cíclica, con el fin de determinar el efecto de la adición de aleantes (cobre y estaño en los potenciales de corrosión, picadura y repasivación. Se ha determinado el efecto del cobre y estaño en la temperatura crítica de picadura mediante el trazado de curvas icon-tiempo. Asimismo se estudió la influencia de estos aleantes en FeCl3, según norma ASTM 048-00. La adición de cobre favorece la nucleación de picaduras. La adición de estaño presenta una tendencia a mejorar la resistencia a la corrosión. El efecto sinérgico Cu-Sn es positivo en bajas concentraciones.

  5. Evaluación de la fuerza de doblado y de fricción en el conformado de chapa de acero inoxidable AISI 304 DDQ mediante ensayos de doblado en condiciones multiaxiales de embutición

    Directory of Open Access Journals (Sweden)

    Coello, J.

    2012-08-01

    Full Text Available Die radius is a critical area from the viewpoint of friction in forming processes. Moreover the sheet, that has been previously deformed in flange area, suffers bending and unbending stresses. Then, die-sheet contact in die radius must be especially considered in order to guarantee the suitable lubrication conditions. In the present work, a test method is carried out for evaluating an AISI 304 DDQ steel under similar conditions to those existing in the die radius area and that, usually, are not really reproduced in traditional bending under tensions tests. Deformation under pure shear condition, the bending and the radius angle have been established as variables of the tests. Results allow to obtain the apparent pressure sheet-bending tool, that increases with bending angle and decreases with tool radius. This last variable is the most significant while the bending angle has lesser influence. Although experimental results present some concordances with values obtained by analytical methods, some corrections must be considered in them in order to improve the theoretical values.

    El radio de entrada a la matriz se considera una de las zonas críticas en los procesos de conformado de chapa mediante embutición profunda. El análisis de la fuerza de fricción y de doblado existentes resulta importante para predecir el comportamiento de la chapa en dicha zona, así como para garantizar una lubricación adecuada a las condiciones de procesado. En el presente trabajo, se aplica un método de ensayo que evalúa las acciones en el proceso de doblado del acero AISI 304 DDQ bajo condiciones similares a las que sufre el material en los procesos de embutición y que no son reproducidas por los clásicos ensayos de doblado bajo tensión. Se establecen como variables la deformación experimentada previamente por el material en condiciones típicas de cortante puro, “pure shear”, el ángulo de doblado y el radio de doblado. Los resultados obtenidos

  6. Microestrutura de uma Solda Dissimilar entre o Aço Inoxidável Ferrítico AISI 410S e o Aço Inoxidável Austenítico AISI 304L Soldado pelo Processo FSW

    OpenAIRE

    Tathiane Caminha Andrade; Cleiton Carvalho Silva; Hélio Cordeiro de Miranda; Marcelo Ferreira Motta; Jesualdo Pereira Farias; Luciano Andrei Bergman; Jorge Fernandes dos Santos

    2015-01-01

    Resumo O presente trabalho visa investigar a microestrutura formada na soldagem dissimilar entre chapas de aços inoxidáveis ferríticos AISI 410S e aços inoxidáveis austeníticos AISI 304L pelo processo friction stir welding. A soldagem foi realizada com o ajuste dos seguintes parâmetros: rotação 450 rpm; velocidade de soldagem de 1,0 mm/s; e força axial 40 kN. O aço AISI 410S foi posicionado no lado de avanço enquanto que o aço AISI 304L foi posicionado no lado de retrocesso. A análise consist...

  7. Comportamiento del acero AISI-SAE 8615 frente al proceso de nitrocarburación ferrítica, utilizando urea-metanol

    Directory of Open Access Journals (Sweden)

    Barrena, M. I.

    1998-06-01

    Full Text Available The present work shows the behaviour of low carbon alloyed steels as AISI-SAE 8615, after a ferritic nitrocarburizing process. Nitrocarburizing takes place at 570ºC for 3 h in an atmosphere by combustion of methanol and urea under different flow rates. Metallographic studies were performed by optical microscopy. Hardness profiles were measured and carbon percentages were also analized by emission spectrometry in order to determine the extension of the nitrocarburizing process. Optimal flow conditions have been found. The influence of the flow rate on the nitrocarburizing layer thickness has been also studied.

    El presente trabajo muestra el comportamiento del acero aleado de bajo contenido de carbono, AISISAE 8615, cuando se somete a un proceso de nitrocarburación ferrítica, a la temperatura de 570ºC y un tiempo de 3 h. La atmósfera reactiva ha sido generada mediante goteo variable de metanol y urea dentro del horno, utilizando distintas velocidades de flujo. Las capas nitrocarburadas fueron evaluadas mediante técnicas de microscopía óptica. Con el fin de conocer la extensión de las capas nitrocarburadas obtenidas, se realizaron medidas de microdureza y se determinaron los porcentajes de carbono en el proceso mediante espectroscopia de emisión. Se han encontrado las condiciones de flujo óptimo de la mezcla anteriormente comentada y se ha observado cómo su variación influye en el espesor de la capa nitrocarburada.

  8. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    Science.gov (United States)

    Grujicic, M.; Ramaswami, S.; Snipes, J. S.; Yavari, R.; Arakere, A.; Yen, C.-F.; Cheeseman, B. A.

    2013-05-01

    A fully coupled (two-way), transient, thermal-mechanical finite-element procedure is developed to model conventional gas metal arc welding (GMAW) butt-joining process. Two-way thermal-mechanical coupling is achieved by making the mechanical material model of the workpiece and the weld temperature-dependent and by allowing the potential work of plastic deformation resulting from large thermal gradients to be dissipated in the form of heat. To account for the heat losses from the weld into the surroundings, heat transfer effects associated with natural convection and radiation to the environment and thermal-heat conduction to the adjacent workpiece material are considered. The procedure is next combined with the basic physical-metallurgy concepts and principles and applied to a prototypical (plain) low-carbon steel (AISI 1005) to predict the distribution of various crystalline phases within the as-welded material microstructure in different fusion zone and heat-affected zone locations, under given GMAW-process parameters. The results obtained are compared with available open-literature experimental data to provide validation/verification for the proposed GMAW modeling effort.

  9. Investigation of the influential parameters of machining of AISI 304 stainless steel

    Indian Academy of Sciences (India)

    R A Mahdavinejad; S Saeedy

    2011-12-01

    Austenitic stainless steels are hard materials to machine, due to their high strength, high ductility and low thermal conductivity. The last characteristic results in heat concentration at the tool cutting edge. This paper aims to optimize turning parameters of AISI 304 stainless steel. Turning tests have been performed in three different feed rates (0.2, 0.3, 0.4 mm/rev) at the cutting speeds of 100, 125, 150, 175 and 200 m/min with and without cutting fluid. A design of experiments (DOE) and an analysis of variance (ANOVA) have been made to determine the effects of each parameter on the tool wear and the surface roughness. It is being inferred that cutting speed has the main influence on the flank wear and as it increases to 175 m/min, the flank wear decreases. The feed rate has the most important influence on the surface roughness and as it decreases, the surface roughness also decreases. Also, the application of cutting fluid results in longer tool life and better surface finish.

  10. Effects of cold working on the pitting corrosion behavior s of AISI 304 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Kee Min; Kim, Jong Soo; Kim, Young Jun; Kwon, Houk Sang [KAIST, Daejon (Korea, Republic of)

    2015-12-15

    These microstructural changes by cold working can lead improvement of mechanical properties, however from a corrosion resistant point of view, the effects of cold working on the corrosion resistance of stainless steel have been argued. Several studies has been focused on the influence of cold working on the localized corrosion resistance of stainless steels. However, the opinions about the role of cold working on the localized corrosion resistance are highly in consistence. Some studies report that the pitting potential of austenitic stainless steels decreased with cold working level, on the other hands, other studies claimed that the pitting resistance was increased by cold working. Therefore it is necessary to verify how cold working affects pitting corrosion behavior of austenitic stainless steels. In the present work, the influence of cold working on the localized corrosion of AISI 304stainless steel in the neutral chloride solution was studied based on point defect model (PDM). The fraction of deformation-induced martensite was linearly increased with cold rolling level. Through cold rolling, the pitting potential was decreased, the metastable pitting event density was significantly increased and the repassivation potential was decreased. The overall localized corrosion resistance was decreased with cold working, however cold working level increased from 30 % to 50 %, localized corrosion resistance was recovered. The accumulated cation vacancy generates a void at metal/film interface, therefore film breakdown accelerates for cold worked alloys.

  11. Pengaruh Media Pendingin pada Heat Treatment Terhadap Struktur Mikro dan Sifat Mekanik Friction Wedge AISI 1340

    Directory of Open Access Journals (Sweden)

    Bayu Adie Septianto

    2013-09-01

    Full Text Available Baja AISI 1340 termasuk baja paduan rendah dengan komposisi karbon 0.38-0.43% dan Mangan 1,78%. Baja ini digunakan untuk komponen kereta api Friction Wedge yang memiliki standar kekerasan minimal 300 BHN. Untuk menambah kekerasan, salah satu cara yang digunakan adalah heat treatment. Pada penelitian ini variasi yang digunakan adalah media pendingin air, oli SAE 20W, PVA 20% dan pendinginan udara pada tempertaur austenitisasi 8400C dan waktu tahan 20 menit. Kekerasan yang dihasilkan oleh media pendingin air adalah 556,6 BHN, sedangkan quench oli dan polimer 461,8 BHN dan 416 BHN. Pada pendinginan udara dihasilkan kekerasan dibawah 300 BHN. Perbedaan media pendingin berpengaruh terhadap struktur mikro yang terbentuk. Pada pendinginan dengan media air dan oli diperoleh struktur martensit dengan bentuk kristal BCT. Sedangkan pada pendinginan udara terbentuk struktur ferrit dan perlit dengan bentuk kristal BCC. Selain berpengaruh pada sifat mekanik dan struktur mikronya, variasi media pendingin juga memberikan efek terhadap sifat termalnya dan berpengaruh terhadap elongation pada temperatur maksimum kerja. Dari hasil uji TMA, performa paling baik pada temperatur 300oC dihasilkan pada pendinginan quench oli SAE 20W, dengan pertambahan panjang sebesar 0,65%.

  12. Multi-response optimization of Micro-EDM process parameters on AISI304 steel using TOPSIS

    Energy Technology Data Exchange (ETDEWEB)

    Manivannan, R.; Kumar, M. Pradeep [CEG, Anna University, Chennai (India)

    2016-01-15

    The Technique for order preference by similarity to ideal solution (TOPSIS) method of optimization is used to analyze the process parameters of the micro-Electrical discharge machining (micro-EDM) of an AISI 304 steel with multi-performance characteristics. The Taguchi method of experimental design L27 is performed to obtain the optimal parameters for inputs, including feed rate, current, pulse on time, and gap voltage. Several output responses, such as the material removal rate, electrode wear rate, overcut, taper angle, and circularity at entry and exit points, are analyzed for the optimal conditions. Among all the investigated parameters, feed rate exerts a greater influence on the hole quality. ANOVA is employed to identify the contribution of each experiment. The optimal level of parameter setting is maintained at a feed rate of 4 μm/s, a current of 10 A, a pulse on time of 10 μs, and a gap voltage of 10 V. Scanning electron microscope analysis is conducted to examine the hole quality. The experimental results indicate that the optimal level of the process parameter setting over the overall performance of the micro-EDM is improved through TOPSIS.

  13. Kinetics of niobium carbide coating produced on AISI 1040 steel by thermo-reactive deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Sen, Ugur

    2004-07-15

    There are a lot of technologically interesting characteristics of niobium carbide coating deposited by pack method which is the production of hard, wear-resistant, oxidation and corrosion resistant coating layer on the steel substrates. In the present study, the growth kinetics of niobium carbide layer deposited by thermo-reactive diffusion techniques in a solid medium on steel samples was reported. Niobium carbide coating treatment was performed on AISI 1040 steels in the powder mixture consisting of ferro-niobium, ammonium chloride and alumina at 1073, 1173 and 1273 K for 1-4 h. The presence of NbC and Nb{sub 2}C phases formed on the surface of the steel substrates was confirmed by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction analyses. Niobium carbide layer thickness ranges from 3.42{+-}0.52 to 11.78{+-}2.29 {mu}m depending upon the treatment time and temperature. Layer growth kinetics was analyzed by measuring the depth of niobium carbide layer as a function of time and temperature. The kinetics of niobium carbide coating by pack method shows a parabolic relationship between carbide layer thickness and treatment time, and the activation energy for the process is estimated to be 91.257 kJ mol{sup -1}. Moreover, an attempt was made to investigate the possibility of predicting the contour diagram of niobium carbide layer variation and to establish some empirical relationships between process parameters and niobium carbide layer thickness.

  14. Microstructure analysis of AISI 304 stainless steel produced by twin-roll thin strip casting process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The microstructure of AISI 304 austenite stainless steel fabricated by the thin strip casting process were investigated using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD).The microstructures of the casting strips show a duplex structure consisting of delta ferrite and austenite. The volume fraction of the delta ferrite is about 9.74vol% at the center and 6.77vol% at the surface of the casting thin strip, in vermicular and band shapes. On account of rapid cooling and solidification in the continuous casting process, many kinds of inclusions and precipitates have been found. Most of the inclusions and precipitates are spherical complex compounds consisting of oxides, such as, SiO2, MnO, Al2O3,Cr2O3,and FeO or their multiplicity oxides of MnO·Al2O3,2FeO·SiO2, and 2MnO·SiO2. Many defects including dislocations and stacking faults have also formed during the rapid cooling and solidification process, which is helpful to improve the mechanical properties of the casting strips.

  15. Thermodynamic modeling and kinetics simulation of precipitate phases in AISI 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Y., E-mail: yangying@ornl.gov [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Busby, J.T. [Fusion and Materials for Nuclear Systems Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2014-05-01

    This work aims at utilizing modern computational microstructural modeling tools to accelerate the understanding of phase stability in austenitic steels under extended thermal aging. Using the CALPHAD approach, a thermodynamic database OCTANT (ORNL Computational Thermodynamics for Applied Nuclear Technology), including elements of Fe, C, Cr, Ni, Mn, Mo, Si, and Ti, has been developed with a focus on reliable thermodynamic modeling of precipitate phases in AISI 316 austenitic stainless steels. The thermodynamic database was validated by comparing the calculated results with experimental data from commercial 316 austenitic steels. The developed computational thermodynamics was then coupled with precipitation kinetics simulation to understand the temporal evolution of precipitates in austenitic steels under long-term thermal aging (up to 600,000 h) at a temperature regime from 300 to 900 °C. This study discusses the effect of dislocation density and difusion coefficients on the precipitation kinetics at low temperatures, which shed a light on investigating the phase stability and transformation in austenitic steels used in light water reactors.

  16. Influence of cyclic temperature changes on the microstructure of AISI 4140 after laser surface hardening

    Energy Technology Data Exchange (ETDEWEB)

    Miokovic, T. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany); Schulze, V. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany)]. E-mail: volker.schulze@mach.uni-karlsruhe.de; Voehringer, O. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany); Loehe, D. [Institute of Materials Science and Engineering I, University of Karlsruhe, 76131 Karlsruhe (Germany)

    2007-01-15

    In recent years laser surface hardening using pulsed laser sources has become an increasingly established technology in engineering industry and has opened up wider possibilities for the application of selective surface hardening. However, the choice of the process parameters is generally based on experience rather than on their empirical influence on the resulting microstructure, and for hardening processes with cyclic temperature changes, almost no correlations between process parameters and hardening results are known. Therefore, some problems regarding the choice of the process parameters and their influence on the resulting microstructure still remain. In particular, there is a lack of data concerning the effect of cyclic temperature changes on hardening. To facilitate process optimization, this paper deals with a detailed characterization of the microstructures created in quenched and tempered AISI 4140 (German grade 42CrMo4) steel following a temperature-dependent laser surface hardening treatment. The structure properties were obtained from microhardness measurements, scanning electron microscopy investigations and X-ray diffraction analysis of retained austenite.

  17. Nano- and Macro-wear of Bio-carbo-nitrided AISI 8620 Steel Surfaces

    Science.gov (United States)

    Arthur, Emmanuel Kwesi; Ampaw, Edward; Zebaze Kana, M. G.; Adetunji, A. R.; Olusunle, S. O. O.; Adewoye, O. O.; Soboyejo, W. O.

    2015-12-01

    This paper presents the results of an experimental study of nano- and macro-scale wear in a carbo-nitrided AISI 8620 steel. Carbo-nitriding is carried out using a novel method that involves the use of dried, cyanide-containing cassava leaves, as sources of carbon and nitrogen. These are used in a pack cementation that is used to diffuse carbon and nitrogen into case layers at intermediate temperatures [673.15 K, 723.15 K, 773.15 K, and 823.15 K (400 °C, 450 °C, 500 °C, and 550 °C)]. Nano- and macro-scale wear properties are studied in the case-hardened surfaces, using a combination of nano-scratch and pin-on-disk experiments. The measured wear volumes (at both nano- and macro-length scales) are shown to increase with decreasing pack cyaniding temperature. The nano- and macro-wear resistances are also shown to be enhanced by the in situ diffusion of carbon and nitrogen from cyanide-containing bio-processed waste. The underlying wear mechanisms are also elucidated via atomic force microscopy and scanning electron microscopy observations of the wear tracks. The implications of the results are discussed for the design of hardened carbo-nitrided steel surfaces with improved wear resistance.

  18. Deposition of titanium nitride on AISI-304 in a plasma focus environment

    Science.gov (United States)

    Zeb, S.; Qayyum, A.; Shafiq, M.; Zakaullah, M.

    2008-05-01

    Polycrystalline, smooth, and hard thin films of TiN are successfully deposited on AISI-304 substrates using a 1.5kJ Mather-type dense plasma focus device charged at 18kV. The purpose of this study is to investigate the structural and mechanical properties of the TiN thin films in terms of ion dose and substrate position to establish the optimum deposition conditions. The films are analyzed using XRD, SEM, electron microprobe and micro-hardness testing. XRD confirms the deposition of a polycrystalline TiN thin film together with the emergence of an iron chromium nickel phase. The surface hardness-in comparison to the unexposed substrate-is found to increase up to 250% when a film is deposited using 30 focus shots at an axial distance of 6cm. SEM micrographs show that the quality of the film is improved with an increasing number of focus shots. The constituent elements of the film are also confirmed by electron microprobe.

  19. Plasma nitriding of AISI 52100 ball bearing steel and effect of heat treatment on nitrided layer

    Indian Academy of Sciences (India)

    Ravindra Kumar; J Alphonsa; Ram Prakash; K S Boob; J Ghanshyam; P A Rayjada; P M Raole; S Mukherjee

    2011-02-01

    In this paper an effort has been made to plasma nitride the ball bearing steel AISI 52100. The difficulty with this specific steel is that its tempering temperature (∼170–200°C) is much lower than the standard processing temperature (∼460–580°C) needed for the plasma nitriding treatment. To understand the mechanism, effect of heat treatment on the nitrided layer steel is investigated. Experiments are performed on three different types of ball bearing races i.e. annealed, quenched and quench-tempered samples. Different gas compositions and process temperatures are maintained while nitriding these samples. In the quenched and quench-tempered samples, the surface hardness has decreased after plasma nitriding process. Plasma nitriding of annealed sample with argon and nitrogen gas mixture gives higher hardness in comparison to the hydrogen–nitrogen gas mixture. It is reported that the later heat treatment of the plasma nitrided annealed sample has shown improvement in the hardness of this steel. X-ray diffraction analysis shows that the dominant phases in the plasma nitrided annealed sample are (Fe2−3N) and (Fe4N), whereas in the plasma nitrided annealed sample with later heat treatment only -Fe peak occurs.

  20. CRYOGENIC AND STRESS RELIEF THERMAL TREATMENTS IN AN AISI D2 STEEL

    Directory of Open Access Journals (Sweden)

    Paula Fernanda da Silva Farina

    2012-06-01

    Full Text Available The effects of cryogenic treatments on an AISI D2 cold work tool steel using X-ray diffraction from syncronton radiation are studied. The aim of this work is to verify the effects of: i time at cryogenic temperatures (3, 10 and 30 hours; ii cryogenic temperatures (–80°C and –196°C; iii stress relief heat treatment (130°C before cryogenic treatments; iv effect of double tempering at 520°C for 2 hours each time, after cryogenic treatment at –196°C for 30 hours, with and without previous stress relief. X-ray diffraction experiments were conducted at the line D10B-XPD of the Laboratório Nacional de Luz Síncrotron and the experimental results were treated using Rietveld refining, with TOPAS Academic in conjunction with cards from the ICCD-PDF 2006 database for austenite, martensite and carbides M7C3and M2C. Tempered samples were characterized using SEM and SEM-FEG. Volume fraction of retained austenite and carbides, as well as changes in the crystal lattices of martensite and austenite are obtained from the X-ray experiments.

  1. Finite Element Simulation of Residual Stresses in Butt Welding of Two AISI 304 Stainless Steel Plates

    Directory of Open Access Journals (Sweden)

    Gurinder Singh Brar

    2013-06-01

    Full Text Available Welding is one of the most reliable and efficient permanent metal joining processes in the industry. When two plates are joined by welding, a very complex thermal cycle is applied to the weldment. Thermal energy applied results in irreversible elastic-plastic deformation and consequently gives rise to the residual stresses in and around fusion zone and heat affected zone (HAZ. It is well established fact that structural integrity of components is substantially affected by the residual stresses when subjected to thermal and structural loads. Presence of residual stresses may be beneficial or harmful for the structural components depending on the nature and magnitude of residual stresses. Using finite element based commercially available software, coupled thermal-mechanical three dimensional finite element model was developed by making an approximate geometry of the butt welded joint. Finite element analysis was performed to understand the complete nature of residual stresses in manual metal arc welded joint of AISI 304 stainless steel plate. Variation of residual stress in the plates in the heat affected zone was also being studied. The results obtained by finite element method agree well with those from X-ray diffraction method as published in literature for the prediction of residual stresses.

  2. Effect of V Notch Shape on Fatigue Life in Steel Beam Made of AISI 1037

    Directory of Open Access Journals (Sweden)

    Qasim Bader

    2014-04-01

    Full Text Available The present work encompasses effect of V notch shape with various geometries and dimensions on fatigue life behavior in steel beam made of Medium Carbon Steel AISI 1037 which has a wide application in industry. Fatigue life of notched specimens is calculated using the fatigue life obtained from the experiments for smooth specimens (reference and by use Numerical method (FEA.The fatigue experiments were carried out at room temperature, applying a fully reversed cyclic load with the frequency of (50Hz and mean stress equal to zero (R= -1, on a cantilever rotating-bending fatigue testing machine. The stress ratio was kept constant throughout the experiment. Different instruments have been used in this investigation like Chemical composition analyzer type (Spectromax ,Tensile universal testing machine type (WDW-100E ,Hardness tester type (HSV- 1000 , Fatigue testing machine model Gunt WP 140, Optical Light Microscope (OLM and Scanning Electron Microscope (SEM were employed to examine the fracture features . The results show that there is acceptable error between experimental and numerical works .

  3. Investigations on Surface Milling of Hardened AISI 4140 Steel with Pulse Jet MQL Applicator

    Science.gov (United States)

    Bashir, Mahmood Al; Mia, Mozammel; Dhar, Nikhil Ranjan

    2016-06-01

    In this article, an experimental investigation was performed in milling hardened AISI 4140 steel of hardness 40 HRC. The machining was performed in both dry and minimal quantity lubricant (MQL) conditions, as part of neat machining, to make a strong comparison of the undertaken machining environments. The MQL was impinged int the form of pulse jet, by using the specially developed pulse-jet-attachment, to ensure that the cutting fluid can be applied in different timed pulses and quantities at critical zones. The tool wear, cutting force and surface roughness were taken as the quality responses while cutting speed, table feed rate and flow rate of the pulse were considered as influential factors. The depth of cut was kept constant at 1.50 mm because of its less significant effects and the straight oil was adopted as cutting fluid in pulse-jet-MQL. The effects of different factors, on the quality responses, are analyzed using ANOVA. It is observed that MQL applicator system exhibits overall better performance when compared to dry milling by reducing surface roughness, cutting force and prolonging tool life but a flow rate of 150 ml/h has tremendous effects on the responses. This investigation and afterward results are expected to aid the industrial practitioner and researcher to adopt the pulse-MQL in high speed milling to prolong tool life, reduce tool wear, diminish cutting force generation and promote better surface finish.

  4. Parametric optimization during machining of AISI 304 Austenitic Stainless Steel using CVD coated DURATOMIC cutting insert

    Directory of Open Access Journals (Sweden)

    M. Kaladhar

    2012-08-01

    Full Text Available In this work, Taguchi method is applied to determine the optimum process parameters for turning of AISI 304 austenitic stainless steel on CNC lathe. A Chemical vapour deposition (CVD coated cemented carbide cutting insert is used which is produced by DuratomicTM technology of 0.4 and 0.8 mm nose radii. The tests are conducted at four levels of Cutting speed, feed and depth of cut. The influence of these parameters are investigated on the surface roughness and material removal rate (MRR. The Analysis Of Variance (ANOVA is also used to analyze the influence of cutting parameters during machining. The results revealed that cutting speed significantly (46.05% affected the machined surface roughness values followed by nose radius (23.7%. The influence of the depth of cut (61.31% in affecting material removal rate (MRR is significantly large. The cutting speed (20.40% is the next significant factor. Optimal range and optimal level of parameters are also predicted for responses.

  5. Influence of gas pressure and substrate temperature on PIII nitrocarburizing process of AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Rahman, A.M. [Physics Department, Faculty of Science, South Valley University, Sohag Branch, Sohag (Egypt) and Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany)]. E-mail: ahmedphys96@hotmail.com; El-Hossary, F.M. [Physics Department, Faculty of Science, South Valley University, Sohag Branch, Sohag (Egypt); Negm, N.Z. [Physics Department, Faculty of Science, South Valley University, Sohag Branch, Sohag (Egypt); Prokert, F. [Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany); Richter, E. [Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany); Moeller, W. [Institute of Ion Beam Physics and Material Research, FWII, Forschungszentrum Rossendorf, 01314 Dresden (Germany)

    2004-12-01

    Plasma immersion ion implantation (PIII) has been used to modify the surface properties of 304 austenitic stainless steel (AISI). The influence of working gas pressure, 0.2-1.0 Pa, and substrate temperature, 300-500 deg. C, on the microstructure, treating rate, nitrogen/carbon concentration depth profile, and surface microhardness was investigated. A gas composition of 25% C{sub 2}H{sub 2}, 75% N{sub 2}, r.f. plasma power input of 350 W, and a negatively biased potential of 30 kV were fixed during the experiment. The experimental results show that the substrate temperature and the diffusion process of nitrogen and carbon depend on the gas pressure inside the plasma chamber. The thickness of the modified layer has been found to be more than 30 {mu}m for samples were treated in the plasma for 60 min. The results show also that the values of diffusion coefficient and surface microhardness of the treated samples are high to be 3.4 x 10{sup -1} {mu}m{sup 2}/s and 1880 kg/mm{sup 2}, respectively.

  6. Influence of gas pressure and substrate temperature on PIII nitrocarburizing process of AISI 304 stainless steel

    Science.gov (United States)

    Abd El-Rahman, A. M.; El-Hossary, F. M.; Negm, N. Z.; Prokert, F.; Richter, E.; Möller, W.

    2004-12-01

    Plasma immersion ion implantation (PIII) has been used to modify the surface properties of 304 austenitic stainless steel (AISI). The influence of working gas pressure, 0.2-1.0 Pa, and substrate temperature, 300-500 °C, on the microstructure, treating rate, nitrogen/carbon concentration depth profile, and surface microhardness was investigated. A gas composition of 25% C2H2, 75% N2, r.f. plasma power input of 350 W, and a negatively biased potential of 30 kV were fixed during the experiment. The experimental results show that the substrate temperature and the diffusion process of nitrogen and carbon depend on the gas pressure inside the plasma chamber. The thickness of the modified layer has been found to be more than 30 μm for samples were treated in the plasma for 60 min. The results show also that the values of diffusion coefficient and surface microhardness of the treated samples are high to be 3.4 × 10-1 μm2/s and 1880 kg/mm2, respectively.

  7. Nitrocarburizing of AISI-304 stainless steel using high-voltage plasma immersion ion implantation

    Energy Technology Data Exchange (ETDEWEB)

    Abd El-Rahman, A.M. [Physics Department, Faculty of Science, Sohag University, 82524 Sohag (Egypt)], E-mail: ahmedphys96@hotmail.com; Mohamed, S.H.; Ahmed, M.R. [Physics Department, Faculty of Science, Sohag University, 82524 Sohag (Egypt); Richter, E.; Prokert, F. [Institut fuer Ionenstrahlphysik und Materialforschung, Forschungszentrum Dresden Rossendorf (Germany)

    2009-05-15

    AISI-304 austenitic stainless steel has been nitrocarburized in N{sub 2} and C{sub 2}H{sub 2} ambient using high-voltage plasma immersion ion implantation (PIII) technology. The use of different PIII treatment times revealed important hints with respect to the microstructural, mechanical and corrosion properties of the nitrocarburized layer. Grazing incidence X-ray diffraction (GIXRD) shows the presence of nitride ({gamma}{sub N} and CrN) and carbide ({gamma}{sub C} and Fe{sub 3}C) phases. Glow discharge optical spectroscopy (GDOS) has been used to characterize the elemental depth profiles in which the thickness of the modified layers is derived. Dynamic microindentation method is used for the study of mechanical performance of the nitrocarburized layer as well as the untreated material. The microhardness has been increased to a maximum value of more than nine times compared to that of the untreated one. The corrosion performance is characterized by potentiodynamic polarization technique and was found to be treatment time dependent.

  8. Selective laser melting of Fe-Ni-Cr layer on AISI H13 tool steel

    Institute of Scientific and Technical Information of China (English)

    Byeong-Don JOO; Jeong-Hwan JANG; Jae-Ho LEE; Young-Myung SON; Young-Hoon MOON

    2009-01-01

    An attempt to fabricate Fe-Ni-Cr coating on AISI H13 tool steel was performed with selective laser melting. Fe-Ni-Cr coating was produced by experimental facilities consisting of a 200 W fiber laser which can be focused to 80 μm and atmospheric chamber which can control atmospheric pressure with N2 or Ar. Coating layer was fabricated with various process parameters such as laser power, scan rate and fill spacing. Surface quality and coating thickness were measured and analyzed. Three different surface patterns, such as typeⅠ, typeⅡand type Ⅲ, are shown with various test conditions and smooth regular pattern is obtained under the conditions as 10 μm of fill spacing, 50-350 mm/s of scan rate and 40 μm of fill spacing, 10-150 mm/s of scan rate. The maximum coating thickness is increased with power elevation or scan rate drop, and average thickness of 10 μm fill spacing is lower than that of 40 μm fill spacing.

  9. Investigation on Friction and Wear of Cold Rolled High Strength Steel against an AISI52100 Counterpart

    Directory of Open Access Journals (Sweden)

    Jiwon Hur

    2017-03-01

    Full Text Available This article investigates the friction and wear of cold rolled high strength steel at various displacement amplitudes. Reciprocal sliding tests are carried out using a ball-on-flat testing apparatus. The tangential force occurring at the contact surface between a high strength steel specimen and an AISI52100 ball is measured during the tests. After each test, the worn surface profile on the steel specimen is determined. Experimental results show that the ratio of the maximum tangential to the normal force remains at 0.7 after an initial rapid increase, and the ratio does not greatly change according to the imposed displacement amplitudes (in the range of 0.05 mm and 0.3 mm. The wear volume loss on the steel specimen increases according to the number of cycles. It is determined that the wear rate of the specimen changes with respect to the imposed displacement amplitude. That is, the wear rate rapidly increases within the displacement amplitude range of 0.05 mm to 0.09 mm, while the wear rate gradually increases when the displacement amplitude is greater than 0.2 mm. The obtained results provide the friction and wear behaviors of cold rolled high strength steel in fretting and reciprocal sliding regimes.

  10. Enhanced mechanical properties of type AISI301LN austenitic stainless steel through advanced thermo mechanical process

    Energy Technology Data Exchange (ETDEWEB)

    Huang Junxia, E-mail: huangjunxia@baosteel.com [Shanghai Baosteel Research Institute, Shanghai 200431 (China); Ye Xiaoning; Gu Jiaqing; Chen Xu [Shanghai Baosteel Research Institute, Shanghai 200431 (China); Xu Zhou [School of Material Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer 69% of strain induced martensite were obtained after 80% thickness reduction at 0 Degree-Sign C. Black-Right-Pointing-Pointer The best annealing regime was determined for diffusional controlled reversion. Black-Right-Pointing-Pointer The effect of grain size on mechanical properties conforms with the H-P relationship. - Abstract: The effect of annealing temperature and time on the grain size of reversed austenite and mechanical properties was studied based on AISI301LN austenitic stainless steel in this paper. Cold rolling at 0 Degree-Sign C was employed to obtain the strain-induced martensite, followed by annealing treatment at the temperature range of 650-900 Degree-Sign C for 1-20 min. The relationship between the volume fraction of strain-induced martensite and cold reduction was analyzed by Ferritescope MP30 and X-ray diffraction. The grain growth of reversed austenite was observed by FEG-SEM and the mechanical properties were determined by tensile tests and Vickers hardness tests. Austenite grain sizes under 3 {mu}m can be obtained after annealing in the range of 700-900 Degree-Sign C for 1-20 min. The finest austenite grain size was produced after annealing at 700 Degree-Sign C for 20 min, which had a good combination of yield strength ( Almost-Equal-To 830 MPa), tensile strength ( Almost-Equal-To 953 MPa) and elongation ( Almost-Equal-To 36%).

  11. Z phase stability in AISI 316LN + Nb austenitic steels during creep at 650 C

    Energy Technology Data Exchange (ETDEWEB)

    Vodarek, Vlastimil [Technical Univ. Ostrava (Czech Republic)

    2010-07-01

    The creep resistance of austenitic CrNi(Mo) steels strongly depends on microstructural stability during creep exposure. Nitrogen additions to CrNi(Mo) austenitic steels can significantly improve the creep strength. One of the most successful methods of improving the long-term creep resistance of austenitic steels is based on increasing the extent of precipitation strengthening during creep exposure. The role of precipitates in the achievements of good creep properties has been extensively studied for a long time. Although many minor phases are now well documented there are still contractions and missing thermodynamic data about some minor phases. This contribution deals with results of microstructural studies on the minor phase evolution in wrought AISI 316LN niobium stabilised steels during long-term creep exposure at 650 C. Microstructural investigations were carried out on specimens taken from both heads and gauge lengths of ruptured test-pieces by means of optical metallography, transmission and scanning electron microscopy. The attention has been paid to evaluation of thermodynamic and dimensional stability of Z phase and other nitrogen bearing minor phases. Only two nitrogen-bearing minor phases formed in the casts investigated: Z phase and M{sub 6}X. The dimensional stability of Z phase particles was very high. (orig.)

  12. Effect of Beam Oscillation on Microstructure and Mechanical Properties of AISI 316L Electron Beam Welds

    Science.gov (United States)

    Kar, Jyotirmaya; Roy, Sanat Kumar; Roy, Gour Gopal

    2017-04-01

    The properties of electron beam-welded AISI 316L stainless steel butt joints prepared with and without beam oscillation were evaluated by microstructural analysis, mechanical testing like microhardness measurements, tensile tests at room and elevated temperature 973 K (700 °C), three-point bend, and Charpy impact tests. All joints, irrespective of being prepared with or without beam oscillation, were found to be defect free. Welds produced by beam oscillation exhibited narrower fusion zone (FZ) with lathy ferrite morphology, while the weld without beam oscillation was characterized by wider FZ and skeletal ferrite morphology. During tensile tests at room and elevated temperature 973 K (700 °C), all samples fractured in the base metal (BM) and showed almost the same tensile properties as that of the BM. However, the notch tensile tests at room temperature demonstrated higher strength for joints prepared with the oscillating beam. Besides, face and root bend tests, as well as Charpy impact tests, showed higher bending strength and notch toughness, respectively, for joints prepared with beam oscillation.

  13. Surface Nanostructure Formations in an AISI 316L Stainless Steel Induced by Pulsed Electron Beam Treatment

    Directory of Open Access Journals (Sweden)

    Yang Cai

    2015-01-01

    Full Text Available High current pulsed electron beam (HCPEB is an efficient technique for surface modifications of metallic materials. In the present work, the formations of surface nanostructures in an AISI 316L stainless steel induced by direct HCPEB treatment and HCPEB alloying have been investigated. After HCPEB Ti alloying, the sample surface contained a mixture of the ferrite and austenite phases with an average grain size of about 90 nm, because the addition of Ti favors the formation of ferrite. In contrast, electron backscattered diffraction (EBSD analyses revealed no structural refinement on the direct HCPEB treated sample. However, transmission electron microscope (TEM observations showed that fine cells having an average size of 150 nm without misorientations, as well as nanosized carbide particles, were formed in the surface layer after the direct HCPEB treatment. The formation of nanostructures in the 316L stainless steel is therefore attributed to the rapid solidification and the generation of different phases other than the steel substrate in the melted layer.

  14. Welding of AA1050 aluminum with AISI 304 stainless steel by rotary friction welding process

    Directory of Open Access Journals (Sweden)

    Chen Ying An

    2010-09-01

    Full Text Available The purpose of this work was to assess the development of solid state joints of dissimilar material AA1050 aluminum and AISI 304 stainless steel, which can be used in pipes of tanks of liquid propellants and other components of the Satellite Launch Vehicle. The joints were obtained by rotary friction welding process (RFW, which combines the heat generated from friction between two surfaces and plastic deformation. Tests were conducted with different welding process parameters. The results were analyzed by means of tensile tests, Vickers microhardness, metallographic tests and SEM-EDX. The strength of the joints varied with increasing friction time and the use of different pressure values. Joints were obtained with superior mechanical properties of the AA1050 aluminum, with fracture occurring in the aluminum away from the bonding interface. The analysis by EDX at the interface of the junction showed that interdiffusion occurs between the main chemical components of the materials involved. The RFW proves to be a great method for obtaining joints between dissimilar materials, which is not possible by fusion welding processes.

  15. Metallurgical response of an AISI 4140 steel to different plasma nitriding gas mixtures

    Directory of Open Access Journals (Sweden)

    Adão Felipe Oliveira Skonieski

    2013-01-01

    Full Text Available Plasma nitriding is a surface modification process that uses glow discharge to diffuse nitrogen atoms into the metallic matrix of different materials. Among the many possible parameters of the process, the gas mixture composition plays an important role, as it impacts directly the formed layer's microstructure. In this work an AISI 4140 steel was plasma nitrided under five different gas compositions. The plasma nitriding samples were characterized using optical and scanning electron microscopy, microhardness test, X-ray diffraction and GDOES. The results showed that there are significant microstructural and morphological differences on the formed layers depending on the quantity of nitrogen and methane added to the plasma nitriding atmosphere. Thicknesses of 10, 5 and 2.5 µm were obtained when the nitrogen content of the gas mixtures were varied. The possibility to obtain a compound layer formed mainly by γ'-Fe4N nitrides was also shown. For all studied plasma nitriding conditions, the presence of a compound layer was recognized as being the responsible to hinder the decarburization on the steel surface. The highest value of surface hardness - 1277HV - were measured in the sample which were nitrided with 3vol.% of CH4.

  16. Effect of Beam Oscillation on Microstructure and Mechanical Properties of AISI 316L Electron Beam Welds

    Science.gov (United States)

    Kar, Jyotirmaya; Roy, Sanat Kumar; Roy, Gour Gopal

    2017-02-01

    The properties of electron beam-welded AISI 316L stainless steel butt joints prepared with and without beam oscillation were evaluated by microstructural analysis, mechanical testing like microhardness measurements, tensile tests at room and elevated temperature 973 K (700 °C), three-point bend, and Charpy impact tests. All joints, irrespective of being prepared with or without beam oscillation, were found to be defect free. Welds produced by beam oscillation exhibited narrower fusion zone (FZ) with lathy ferrite morphology, while the weld without beam oscillation was characterized by wider FZ and skeletal ferrite morphology. During tensile tests at room and elevated temperature 973 K (700 °C), all samples fractured in the base metal (BM) and showed almost the same tensile properties as that of the BM. However, the notch tensile tests at room temperature demonstrated higher strength for joints prepared with the oscillating beam. Besides, face and root bend tests, as well as Charpy impact tests, showed higher bending strength and notch toughness, respectively, for joints prepared with beam oscillation.

  17. Corrosion of aluminium, stainless steels and AISI 680 nickel alloy in nitrogen-based fuels

    Energy Technology Data Exchange (ETDEWEB)

    Kap, I.; Starostin, M.; Shter, G.E.; Grader, G.S. [Department of Chemical Engineering, Technion-Israel Institute of Technology, Haifa (Israel)

    2012-07-15

    Nitrogen-based compounds can potentially be used as alternative non-carbon or low-carbon fuels. Nevertheless, the corrosion of construction materials at high temperatures and pressures in the presence of such fuel has not been reported yet. This work is focused on the corrosion of AISI Al 6061, 1005 carbon steel (CS), 304, 316L, 310 austenitic stainless steels (SS) and 680 nickel alloy in highly concentrated water solution of ammonium nitrate and urea (ANU). The corrosion at 50 C and ambient pressure and at 350 C and 20 bar was investigated to simulate storage and working conditions. Sodium chloride was added to the fuel (0-5 wt%) to simulate industrial fertilizers and accelerated corrosion environment. Heavy corrosion of CS was observed in ANU solution at 50 C, while Al 6061, 304 and 316L SS showed high resistance both to uniform and pitting corrosion in ANU containing 1% of sodium chloride. Addition of 5% sodium chloride caused pitting of Al 6061 but had no influence on the corrosion of SS. Tests in ANU at 350 C and 20 bar showed pitting on SS 304 and 316L and 680 nickel alloy. The highest corrosion resistance was found for SS 310 due to formation of stable oxide film on its surface. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  18. Surface roughness evaluation of various cutting materials in hard turning of AISI H11

    Directory of Open Access Journals (Sweden)

    H. Aouici

    2016-04-01

    Full Text Available This paper describes a comparison of surface roughness between ceramics and cubic boron nitride (CBN7020 cutting tools when machining of AISI H11 hot work steels treated at 50 HRC. Plan is designed according to Taguchi’s L18 (21×32 orthogonal array. The response surface methodology (RSM and analysis of variance (ANOVA were used to check the validity of multiple linear regression models and to determine the effects, contribution, significance and optimal machine settings of process parameters, namely, cutting speed, feed rate and depth of cut on machining parameters on the Ra and Rt. The results of this research work showed that, the feed rate was found to be a dominant factor on the surface roughness, followed by the cutting speed, lastly the depth of cut. The CBN7020 cutting tool showed the better performance than that of ceramic based cutting tool. In addition, the combination of low feed rate and high cutting speed is necessary for minimizing the surface roughness.

  19. An experimental investigation of pulsed laser-assisted machining of AISI 52100 steel

    Science.gov (United States)

    Panjehpour, Afshin; Soleymani Yazdi, Mohammad R.; Shoja-Razavi, Reza

    2014-11-01

    Grinding and hard turning are widely used for machining of hardened bearing steel parts. Laser-assisted machining (LAM) has emerged as an efficient alternative to grinding and hard turning for hardened steel parts. In most cases, continuous-wave lasers were used as a heat source to cause localized heating prior to material removal by a cutting tool. In this study, an experimental investigation of pulsed laser-assisted machining of AISI 52100 bearing steel was conducted. The effects of process parameters (i.e., laser mean power, pulse frequency, pulse energy, cutting speed and feed rate) on state variables (i.e., material removal temperature, specific cutting energy, surface roughness, microstructure, tool wear and chip formation) were investigated. At laser mean power of 425 W with frequency of 120 Hz and cutting speed of 70 m/min, the benefit of LAM was shown by 25% decrease in specific cutting energy and 18% improvement in surface roughness, as compared to those of the conventional machining. It was shown that at constant laser power, the increase of laser pulse energy causes the rapid increase in tool wear rate. Pulsed laser allowed efficient control of surface temperature and heat penetration in material removal region. Examination of the machined subsurface microstructure and microhardness profiles showed no change under LAM and conventional machining. Continuous chips with more uniform plastic deformation were produced in LAM.

  20. Surface severe plastic deformation of AISI 304 via conventional shot peening, severe shot peening and repeening

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Okan, E-mail: unalokan78@gmail.com [Mechanical Engineering Department, Bartın University, Bartın 74100 (Turkey); Varol, Remzi [Mechanical Engineering Department, Suleyman Demirel University, Isparta 32200 (Turkey)

    2015-10-01

    Highlights: • CSP and SSP treatments transform austenite to metastable martensite structure. • Nanograin layer thickness after CSP and SSP is 8 μm and 22 μm, respectively. • Shot peening leads to carbon segregation from coarse to nano grain layer. • Repeening is an effective way to reduce surface roughness. - Abstract: Air blast conventional shot peening (CSP), severe shot peening (SSP) and repeening (RP) as a severe plastic deformation applications on AISI 304 austenitic stainless steel is addressed. Shot peened specimens are investigated based on optical, FESEM and digital microscope. The investigations present the austenite transformation to metastable martensite via mechanical twinning due to plastic deformation with high strain rates. It is found that SSP induces thicker nanograin layer with compared to CSP. In XRD studies, the austenite peaks broaden by means of severe shot peening and FWHM increase reveals the grain size reduction below 25 nm regimes on the surface. In EDAX line analysis of CSP specimen, carbon content increase has been detected from deformed layer through the nanocrystalline layer then the content reduces. The carbon segregation takes place due to the energy level distinction between dislocations and Fe−C bonds. 3d contour digital microscope studies and roughness investigations reveal that SSP has deleterious side effect on the surface roughness and surface flatness. However, RP is an effective way to reduce the surface roughness to reasonable values.

  1. Effect of Austenitizing Heat Treatment on the Microstructure and Hardness of Martensitic Stainless Steel AISI 420

    Science.gov (United States)

    Barlow, L. D.; Du Toit, M.

    2012-07-01

    The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 °C, followed by oil quenching. The as-quenched microstructures were found to range from almost fully martensitic structures to martensite with up to 35% retained austenite after quenching, with varying amounts of carbides. Optical and scanning electron microscopy was used to characterize the microstructures, and X-ray diffraction was employed to identify the carbide present in the as-quenched structures and to quantify the retained austenite contents. Hardness tests were performed to determine the effect of heat treatment on mechanical properties. As-quenched hardness values ranged from 700 to 270 HV, depending on the amount of retained austenite. Thermodynamic predictions (using the CALPHAD™ model) were employed to explain these microstructures based on the solubility of the carbide particles at various austenitizing temperatures.

  2. Effects of Ti-C:H coating and plasma nitriding treatment on tribological, electrochemical, and biocompatibility properties of AISI 316L.

    Science.gov (United States)

    Kao, W H; Su, Y L; Horng, J H; Zhang, K X

    2016-08-01

    Ti-C:H coatings were deposited on original, nitrided, and polished-nitrided AISI 316L stainless steel substrates using a closed field unbalanced magnetron sputtering system. Sliding friction wear tests were performed in 0.89 wt.% NaCl solution under a load of 30 N against AISI 316L stainless steel, Si3N4, and Ti6Al4V balls, respectively. The electrochemical properties of the various specimens were investigated by means of corrosion tests performed in 0.89 wt.% NaCl solution at room temperature. Finally, the biocompatibility properties of the specimens were investigated by performing cell culturing experiments using purified mouse leukemic monocyte macrophage cells (Raw264.7). In general, the results showed that plasma nitriding followed by Ti-C:H coating deposition provides an effective means of improving the wear resistance, anti-corrosion properties, and biocompatibility performance of AISI 316L stainless steel.

  3. Nondestructive measurement of the residual stress TiN thin film coated on AISI 304 substrate by x-ray stress analyzer

    Science.gov (United States)

    Zhang, Y. K.; Feng, A. X.; Lu, J. Z.; Kong, D. J.; Tang, C. P.

    2006-01-01

    Titanium nitride films are deposited on AISI 304 steel with a hollow-cathode-discharge (HCD) ion-plating technique. The status of residual stresses in TiN thin film coated on AISI304 substrate by HCD is studied by x-ray diffraction stress analyzer. By analyzing morphology of the residual stress of TiN thin film at interface between TiN film and AISI 304 substrate, the adhering mechanism of TiN thin film is understood as follows: the mechanical interlocking had important contribution to the adhesion strength, the thermal stress is the major factor which resulting TiN thin film peeling off spontaneously. The results show that the value of thin film is -210MPa~-650Mpa, and the thermal stress is compressive, the intrinsic stress is tensile, origins of the residual stress are primarily discussed.

  4. Comparative study of the microbiological corrosion among an AISI 304L and an API X65; Estudio comparativo de la corrosion microbiologica entre un AISI 304L y un API X65

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Arganis J, C.; Luna C, P.; Carapia M, L. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico); Gonzalez F, E. [ITT, Toluca, Estado de Mexico (Mexico)

    2004-07-01

    Metallic samples of AISI 304L sensitized and API X65, were subjected to the action of an inoculated media with reductive sulphate microorganisms (SBR), carrying out electrochemical evaluations by means of the techniques of Polarization Resistance (RP), Tafel extrapolation (ET) and Electrochemical Noise (RE). The generated information was complemented with the analysis and diagnostic of the present damage in the surfaces exposed in both metals. The used electrochemical techniques allow to determine the corrosion velocities associated to each system, establishing that the uniform corrosion is not affected by the effect of the microorganisms; however, electrochemical noise, evidenced the formation of stings associated to the presence of bacteria. (Author)

  5. Dimensional characteristics of welds performed on AISI 1045 steel by means of the application of high power diode laser; Caracteristicas dimensionales de soldadura formadas sobre el acero AISI 1045 mediante la aplicacion del laser diodo de alta potencia

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Castillo, A.; Pou, J.; Lusquinos, F.; Quintero, F.; Soto, R.; Boutinguiza, M.; Saavedra, M.; Perez-Amor, M.

    2004-07-01

    The named High Power diode Laser (HPDL), emits a beam of optical energy generated by diode stimulation and offers the capability of supplying levels of power up to 6 kW. The objective of this research work was to study the main welding variables and their effects on dimensional characteristics of the beads performed by means of application of this novel laser. The results obtained, show that HPDL, is an energy source able to perform welds on AISI 1045 steel plates under conduction mode, without any kind of mechanized preparation, preheating or post-weld treatment and, without filler metal application. (Author) 16 refs.

  6. Influence of sintering atmosphere on the mechanical properties of steel P / M AISI 430L; Influencia de la atmosfera de sinterizacion en las propiedades mecanicas de los aceros P/M AISI 430L

    Energy Technology Data Exchange (ETDEWEB)

    Iglesias, F. J.; Martinez, C.; Costes, M. T.; Ruiz, J. M.; Garcia, L. E.; Corpas, F.

    2014-04-01

    It has studied the stainless steel powder metallurgy AISI 430L. It has compared the sintering in two different atmospheres; in vacuum, and in an atmosphere containing nitrogen. It has developed a heat treatment with the aim of improving the mechanical properties. This has been done through microstructural modification of complex nitrides of iron and chromium precipitates during the phase of sintering. Physical properties have been evaluated and are been performing a microstructural analysis for microstructure related to the increase in mechanical properties. (Author)

  7. Formation of abrasion-resistant coatings of the AlSiFexMny intermetallic compound type on the AISI 304L alloy

    Directory of Open Access Journals (Sweden)

    Martínez-Perales, Laura G.

    2016-03-01

    Full Text Available The α-Al9FeMnSi and β-Al9FeMn2Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 °C, pressure (5, 10 y 20 MPa and holding time (3600, 5400 y 7200 seconds. Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 °C, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of α-Al9FeMnSi and β-Al9FeMn2Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface.Los intermetálicos α-Al9FeMnSi y β-Al9FeMn2Si formados por sinterización reactiva de polvos Al, Si, Mn, Fe, Cr, Ni se han utilizado en aceros AISI 304L para mejorar la microdureza. Las variables de procesamiento de sinterización reactiva fueron temperatura (600, 650, 700, 750, y 800 °C, presión (5, 10 y 20 MPa y el tiempo de retención (3600, 5400 7200 segundos. Los resultados experimentales muestran que la temperatura es la variable más importante que afecta a la formación del sustrato/recubrimiento, mientras que la presión no parece tener un efecto significativo una influencia significativa. Los resultados muestran las condiciones óptimas de la sinterización reactiva que favorecen la formación del sustrato/recubrimiento a 800 °C, 20 MPa y 7200 segundos. En estas condiciones, la zona de reacción entre el sustrato y el recubrimiento es más compacta y bien

  8. Modification of AISI M2 high speed tool steels after laser surface melting under different operation conditions; Modificacion de los aceros rapidos de herramientas AISI M2 por fusion superficial con laser bajo diferentes condiciones de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Arias, J.; Cabeza, M.; Castro, G.; Feijoo, I.; Merino, P.; Pena, G.

    2010-07-01

    We applied a laser surface melting treatment to AISIM2 high-speed steel hardened and tempered- and studied the resulting surface characteristics (microstructure) and mechanical behavior (hardness and wear performance). The steel was treated using a Nd:YAG continuous-wave laser with different operation conditions. The influence of the laser processing parameters on the single tracks and on melted surface layer obtained by multipass system with 50% overlap were studied. The microstructure for all conditions is formed by MC- and M{sub 2}C-type carbides, martensite and retained austenite; the quantities of this phase depends on the operations conditions. It has been determined that low levels of power density and high speed scanning of the beam leads to greater homogeneity in the microstructure with high hardness values and wear resistance. (Author) 26 refs.

  9. Arteterapia con personas con discapacidad intelectual

    OpenAIRE

    Lorenzo Pipkau, Milena

    2015-01-01

    Este proyecto pretende hacer una aproximaci??n al mundo del Arte Terapia y los beneficios que esta disciplina puede aportar a las personas con discapacidad intelectual. La idea surge de la experiencia previa de la autora en este ??mbito y con este colectivo. A trav??s de la documentaci??n bibliogr??fica se busca ampliar el conocimiento en cuanto al concepto de arteterapia y sus antecedentes, con la finalidad de elaborar una propuesta pr??ctica que se basar?? en el dise??o de un taller de arte...

  10. Comparative study on structure, corrosion and hardness of Zn-Ni alloy deposition on AISI 347 steel aircraft material

    Energy Technology Data Exchange (ETDEWEB)

    Gnanamuthu, RM. [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of); Mohan, S., E-mail: sanjnamohan@yahoo.com [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Saravanan, G. [Central Electrochemical Research Institute, (CSIR), Karaikudi 630 006, Tamilnadu (India); Lee, Chang Woo, E-mail: cwlee@khu.ac.kr [Department of Chemical Engineering, College of Engineering, Kyung Hee University, 1732 Deogyeong-daero, Gihung, Yongin, Gyeonggi 446-701 (Korea, Republic of)

    2012-02-05

    Highlights: Black-Right-Pointing-Pointer Electrodeposition of Zn-Ni alloy on AISI 347 steel as an aircraft material has been carried out from various baths. Black-Right-Pointing-Pointer The effect of pulse duty cycle on thickness, current efficiency and hardness reached maximum values at 40% duty cycle and for 50 Hz frequencies average current density of 4 A dm{sup -2}. Black-Right-Pointing-Pointer The XRF characterizations of 88:12% Zn-Ni alloy provided excellent corrosion resistance. Black-Right-Pointing-Pointer It is found that Zn-Ni alloy on AISI 347 aircraft material has better structure and corrosion resistance by pulse electrodeposits from electrolyte-4. - Abstract: Zn-Ni alloys were electrodeposited on AISI 347 steel aircraft materials from various electrolytes under direct current (DCD) and pulsed electrodepositing (PED) techniques. The effects of pulse duty cycle on thickness, current efficiency and hardness of electrodeposits were studied. Alloy phases of the Zn-Ni were indexed by X-ray diffraction (XRD) techniques. Microstructural morphology, topography and elemental compositions were characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray fluorescence spectroscopy (XRF). The corrosion resistance properties of electrodeposited Zn-Ni alloy in 3.5% NaCl aqueous solution obtained by DCD and PED were compared using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) technique. Elemental analysis showed that 88% of Zn and 12% of Ni obtained from electrolyte-4 by PED technique at 40% duty cycle for 50 Hz frequencies having better corrosion resistance than that of deposits obtained from other electrolytes.

  11. Analyses of oxide films grown on AISI 304L stainless steel and Incoloy 800HT exposed to supercritical water environment

    Energy Technology Data Exchange (ETDEWEB)

    Fulger, Manuela, E-mail: manuela.fulger@nuclear.ro [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania); Mihalache, Maria; Ohai, Dumitru [Institute for Nuclear Research Pitesti, POB 78, Campului Street, No. 1, 115400 Mioveni (Romania); Fulger, Stefan [University Politechnica Bucharest, Splaiul Independentei Street, No. 313, Bucharest 060042 (Romania); Valeca, Serban Constantin [University of Pitesti, Targul din Vale Street, No. 1, 110040 Pitesti (Romania)

    2011-08-15

    Supercritical water (SCW) is being considered as a cooling medium for the next generation nuclear reactors because it provides high thermal efficiency and plant simplification. However, materials corrosion has been identified as a critical problem due to the oxidative nature of supercritical water. Thus, for safety using of these nuclear reactor systems a systematic study of candidate materials corrosion is needed. As in other high temperature environments, corrosion in SCW occurs by the growth of an oxide layer on the materials surface. The current work aims to evaluate oxidation behavior of AISI 304L SS and Incoloy 800HT in water at supercritical temperatures in the range 723-873 K under a pressure of 25 MPa for up to 1680 h. After exposure to deaerated supercritical water, the samples were investigated using gravimetry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). Oxide films grown on these materials have a layered structure with an outer layer consisting of a mixture of iron oxide/iron-nickel spinel oxides and an inner layer consisting of chromium oxide in the case of Incoloy 800HT and nickel-chromium spinel oxide in the case of AISI 304L SS. The mass gains for Incoloy 800HT at all temperatures were small, while comparatively with AISI 304L SS which exhibited higher oxidation rates. In the same time the results obtained by EIS indicate the best corrosion resistance of oxides grown on Incoloy 800HT surface.

  12. Formation of amorphous Ti alloy layers by excimer laser mixing of Ti on AISI 304 stainless-steel surfaces

    Science.gov (United States)

    Jervis, T. R.; Nastasi, M.; Zocco, T. G.; Martin, J. A.

    1988-07-01

    We used excimer laser radiation at 308 nm to mix thin layers of Ti into AISI 304 stainless steel. Different numbers of shots at a fluence about twice the threshold for melting varied the amount of mixing. When mixing is sufficiently complete, an amorphous surface layer is formed with Ti substituting for Fe on a one-to-one basis in the alloy. The laser mixing process, unlike Ti ion implantation, does not result in high incorporation of C in the processed layer, although some C from surface and interface contamination is incorporated into the surface layer.

  13. Effect of martensite to austenite reversion on the formation of nano/submicron grained AISI 301 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Karimi, M.; Najafizadeh, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, A., E-mail: ahmad_k@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Eskandari, M. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2009-11-15

    The martensite to austenite reversion behavior of 90% cold rolled AISI 301 stainless steel was investigated in order to refine the grain size. Cold rolled specimens were annealed at 600-900 deg. C, and subsequently characterized by scanning electron microscopy, X-ray diffraction, Feritscope, and hardness measurements. The effects of annealing parameters on the formation of fully-austenitic nano/submicron grained structure and the mechanisms involved were studied. It was found that annealing at 800 deg. C for 10 s exhibited the smallest average austenite grain size of 240 {+-} 60 nm with an almost fully-austenitic structure.

  14. OPTIMIZATION OF SURFACE ROUGHNESS OF AISI 304 AUSTENITIC STAINLESS STEEL IN DRY TURNING OPERATION USING TAGUCHI DESIGN METHOD

    OpenAIRE

    D. PHILIP SELVARAJ; Chandramohan, P.

    2010-01-01

    The present work is concentrated with the dry turning of AISI 304 Austenitic Stainless Steel (ASS). This paper presents the influence of cutting parameters like cutting speed, feed rate and depth of cut on the surface roughness of austenitic stainless steel during dry turning. A plan of experiments based on Taguchi’s technique has been used to acquire the data. An orthogonal array, the signal to noise (S/N) ratio and the analysis of variance (ANOVA) are employed to investigate the cutting cha...

  15. Effect of Cl– on the corrosive wear of AISI 321 stainless steel in H2SO4 solution

    Indian Academy of Sciences (India)

    Yanliang Huang; Xiaoxia Jiang; Sizuo Li

    2003-06-01

    The effect of Cl– on the corrosive wear behaviour of AISI 321 stainless steel in H2SO4 solution was studied via the corrosive wear rate, the load bearing capacity of passive film and the relationship between pitting and corrosive wear. There is a critical load at natural potential, below which the corrosive wear rate is slightly lowered by Cl–, while above which is increased. At natural potential there are more pits at low load than that at a higher one in the wear tracks and the pits are also deeper. The load bearing capacity is lowered by Cl– at passive region and then the corrosive wear rate increased.

  16. Investigation And Optimization Of EDM Process Of AISI 4140 Alloy Steel Using Various Tool Electrodes: A Review Paper

    Directory of Open Access Journals (Sweden)

    Kishor Lal ,

    2014-11-01

    Full Text Available The purpose of this research work is to determine the optimized settings of key machining factors like pulse on time, discharge current and duty cycle for AISI 4140 alloy steel using various tool electrodes. The output responses will be measured are material removal rate (MRR,surface roughness(SR and tool wear rate(TWR. Mathematical models are proposed for the above are L27 orthogonal array. The micro structural changes in the work piece after machining process will also be examined by the use of SEM.

  17. Investigation of AISI 441 Ferritic Stainless Steel and Development of Spinel Coatings for SOFC Interconnect Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhenguo; Xia, Guanguang; Wang, Chong M.; Nie, Zimin; Templeton, Joshua D.; Singh, Prabhakar; Stevenson, Jeffry W.

    2008-05-30

    As part of an effort to develop cost-effective ferritic stainless steel-based interconnects for solid oxide fuel cell (SOFC) stacks, both bare and spinel coated AISI 441 were studied in terms of metallurgical characteristics, oxidation behavior, and electrical performance. The conventional melt metallurgy used for the bulk alloy fabrication leads to significant processing cost reduction and the alloy chemistry with the presence of minor alloying additions of Nb and Ti facilitate the strengthening by precipitation and formation of Laves phase both inside grains and along grain boundaries during exposure in the intermediate SOFC operating temperature range. The Laves phase formed along the grain boundaries also ties up Si and prevents the formation of an insulating silica layer at the scale/metal interface during prolonged exposure. The substantial increase in ASR during long term oxidation due to oxide scale growth suggested the need for a conductive protection layer, which could also minimize Cr evaporation. In particular, Mn1.5Co1.5O4 based surface coatings on planar coupons drastically improved the electrical performance of the 441, yielding stable ASR values at 800ºC for over 5,000 hours. Ce-modified spinel coatings retained the advantages of the unmodified spinel coatings, and also appeared to alter the scale growth behavior beneath the coating, leading to a more adherent scale. The spinel protection layers appeared also to improve the surface stability of 441 against the anomalous oxidation that has been observed for ferritic stainless steels exposed to dual atmosphere conditions similar to SOFC interconnect environments. Hence, it is anticipated that, compared to unmodified spinel coatings, the Ce-modified coatings may lead to superior structural stability and electrical performance.

  18. Surface Texturing-Plasma Nitriding Duplex Treatment for Improving Tribological Performance of AISI 316 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Naiming Lin

    2016-10-01

    Full Text Available Surface texturing-plasma nitriding duplex treatment was conducted on AISI 316 stainless steel to improve its tribological performance. Tribological behaviors of ground 316 substrates, plasma-nitrided 316 (PN-316, surface-textured 316 (ST-316, and duplex-treated 316 (DT-316 in air and under grease lubrication were investigated using a pin-on-disc rotary tribometer against counterparts of high carbon chromium bearing steel GCr15 and silicon nitride Si3N4 balls. The variations in friction coefficient, mass loss, and worn trace morphology of the tested samples were systemically investigated and analyzed. The results showed that a textured surface was formed on 316 after electrochemical processing in a 15 wt % NaCl solution. Grooves and dimples were found on the textured surface. As plasma nitriding was conducted on a 316 substrate and ST-316, continuous and uniform nitriding layers were successfully fabricated on the surfaces of the 316 substrate and ST-316. Both of the obtained nitriding layers presented thickness values of more than 30 μm. The nitriding layers were composed of iron nitrides and chromium nitride. The 316 substrate and ST-316 received improved surface hardness after plasma nitriding. When the tribological tests were carried out under dry sliding and grease lubrication conditions, the tested samples showed different tribological behaviors. As expected, the DT-316 samples revealed the most promising tribological properties, reflected by the lowest mass loss and worn morphologies. The DT-316 received the slightest damage, and its excellent tribological performance was attributed to the following aspects: firstly, the nitriding layer had high surface hardness; secondly, the surface texture was able to capture wear debris, store up grease, and then provide continuous lubrication.

  19. Fatigue life improvements of the AISI 304 stainless steel ground surfaces by wire brushing

    Science.gov (United States)

    Ben Fredj, Nabil; Ben Nasr, Mohamed; Ben Rhouma, Amir; Sidhom, Habib; Braham, Chedly

    2004-10-01

    The surface and subsurface integrity of metallic ground components is usually characterized by an induced tensile residual stress, which has a detrimental effect on the fatigue life of these components. In particular, it tends to accelerate the initiation and growth of the fatigue cracks. In this investigation, to deliberately generate compressive residual stresses into the ground surfaces of the AISI 304 stainless steel (SS), wire brushing was applied. It was found that under the experimental conditions selected in this investigation, while the surface roughness was slightly improved by the brushing process, the surface residual stress shifted from a tensile stress (σ‖=+450 MPa) to a compressive stress (σ‖=-435 MPa). On the other hand, the work-hardened deformation layer was almost two times deeper after wire brushing. Concerning the fatigue life, an improvement of 26% in terms of endurance limit at 2×106 cycles was realized. Scanning electron microscope (SEM) observations of the fatigue fracture location and size were carried out to explain the fatigue life improvement. It was found that the enhancement of the fatigue strength could be correlated with the distribution and location of the fatigue fracture nucleation sites. Concerning the ground surfaces, it was seen that the fatigue cracks initiated at the bottom of the grinding grooves and were particularly long (150-200 µm). However, the fatigue cracks at the brushed surfaces were shorter (20-40 µm) and appeared to initiate sideways to the plowed material caused by the wire brushing. The results of the wire-brushed surface characterization have shown that significant advantages can be realized regarding surface integrity by the application of this low-cost process compared to shot peening.

  20. Ensayos de rozamiento plano sobre aceros inoxidables austeníticos con diferente acabado superficial. Determinación de las condiciones de adhesión en el rozamiento

    Directory of Open Access Journals (Sweden)

    Coello, J.

    2008-12-01

    Full Text Available The main purpose of this work is to evaluate the tribological behaviour of austenic stainless steels AISI 304 with bright annealed surface finishing (BA (ASTM a 240; AISI 304 DDQ and AISI 316 with bright surface finishing (B. The assays have been carried out in flat faced dies system with mineral oil of 200 cts viscosity, S2Mo grease and in dry conditions.. The relationship between friction coefficient and pressure and velocity has been established for the mineral oil as lubricant. In these conditions, a strong adhesive tendency has been found in boundary lubrication regime. The results obtained here, show us that S2Mo grease leads to lowest values for the friction coefficient. A minor adhesive behaviour tendency for AISI 316 steel, harder than 304 grades, has been found. A relevant plowing phenomena has been observed for the more critical friction conditions tried out. A surface hardener is produced as a consequence of that.

    El objetivo de este trabajo es determinar el comportamiento tribológico de los aceros inoxidables austeníticos 304 con acabado brillante BA (ASTM A 240, 304 DDQ y 316 con acabado mate 2B, en sistemas de contacto plano, con el fin de simular el rozamiento en la zona del flanco en los procesos de embutición de acero inoxidable. Para ello, se ha estudiado la influencia del acabado superficial del acero, la velocidad de deslizamiento y la presión normal sobre el coeficiente de rozamiento, utilizando un ensayo de fricción con matrices planas. Los ensayos se han realizado con aceite mineral de 200 cst, grasa de bisulfuro de molibdeno y en seco. En presencia de aceite, se ha establecido una correlación de m con la velocidad de deslizamiento y la presión de contacto con comportamiento fuertemente adhesivo en las condiciones de lubricación límite consideradas. Los resultados obtenidos muestran que la grasa de bisulfuro de molibdeno disminuye en un 50 % los valores del coeficiente de rozamiento

  1. Flydende fase sintring af rustfrit stål

    DEFF Research Database (Denmark)

    Maahn, Ernst Emanuel; Mathiesen, Troels

    1998-01-01

    on addition of boride to AISI 316L type steels has previously proved to be sensitive to intergranular corrosion due to formation of intermetallic phases. In order to improve this system further, application of other alloy systems based on a higher alloyed 904L type stainless steel powder (PM 150) has been...

  2. Very high cycle regime fatigue of thin walled tubes made from austenitic stainless steel

    DEFF Research Database (Denmark)

    Carstensen, J.V.; Mayer, H.; Brøndsted, P.

    2002-01-01

    Fatigue life data of cold worked tubes (diameter 4 mm, wall thicknesses 0.25 and 0.30 mm) of an austenitic stainless steel, AISI 904 L, were measured in the regime ranging from 2 × 105 to 1010 cycles to failure. The influence of the loading frequency was investigated as data were obtained...

  3. Study of the tensile behavior of AISI type 316 stainless steel using acoustic emission and infrared thermography techniques

    Directory of Open Access Journals (Sweden)

    Thodamrakandy Haneef

    2015-07-01

    Full Text Available Acoustic emission (AE and infrared thermography technique (IRT have been used to study the tensile behavior of AISI type 316 stainless steel. Strain rates of tensile testing were varied from 1.4 × 10−3 s−1 to 1.4 × 10−2 s−1. AE root mean square voltage increases with increase in strain rate due to the increase in source activation. Dominant frequency of the AE signals generated during different regions of tensile deformation has also been used to compare the results for different strain rates. The dominant frequency increases from elastic region to around 590 kHz during work hardening and 710 kHz around ultimate tensile strength (UTS for all the strain rates. Temperature changes during different regions of deformation are monitored using infrared thermography. The temperature rise in the work hardening region is found to approximately increase linearly with time and from the slopes of the linear regression analyses the rate of temperature rise in the work-hardening region is obtained which is found to be very sensitive to strain rates. From the experimental results an empirical equation that relates the rate of temperature increase with strain rate and thermal hardening coefficient is obtained. The correlation between the variation of AE dominant frequency and temperature rise during different deformation regions provided better insight into the tensile behavior of AISI type 316 SS for different strain rates.

  4. Phase transformations in an AISI 410S stainless steel observed in directional and laser-induced cooling regimes

    Directory of Open Access Journals (Sweden)

    Milton Sergio Fernandes de Lima

    2012-02-01

    Full Text Available The applications of the chromium ferritic stainless steel AISI 410S have been considerably increased in the last years in many technical fields as chemical industries and oil or gas transportation. However, the phase transformation temperatures are, currently, unknown for this alloy. The aim of this work is to determine the alpha to gamma transformation temperatures of the AISI 410S alloy in different cooling conditions and to analyze them using continuous cooling theory. In order to achieve different cooling rates and thermal conditions, two complementary techniques were used: Bridgman furnace crystal growth and laser remelting technique. The measured solidification temperature was around 1730 and 1750 K. Plate-like and dendritic austenite precipitates were obtained in solid-state phase using growth rates between 5 and 10 µm/s in directional growth experiments. Only plate-like austenite phase was observed in the experiments using growth rates above 100 µm/s. The appearance of dendrites, with the consequent segregation of the elements, can be previously determined by the microstructure modeling currently proposed. Massive austenite can be produced from 0.3 to 10 mm/s rates at temperatures between 1100-1300 K. The structure might be less sensitive to corrosion because this phase is produced without microsegregation.

  5. Tribological properties of CrN coatings deposited by nitro-chromizing treatment on AISI D2 steel

    Energy Technology Data Exchange (ETDEWEB)

    Durmaz, M., E-mail: mdurmaz@sakarya.edu.tr; Abakay, E.; Sen, U.; Sen, S. [Department of Metallurgical and Materials Engineering, Engineering Faculty, Sakarya University, Esentepe Campus, 54187 Sakarya (Turkey); Kilinc, B. [Department of Metallurgical and Materials Engineering, Institute of Arts and Sciences, Sakarya University, Esentepe Campus, 54187 Sakarya (Turkey)

    2015-03-30

    In this work, the wear test of uncoated and chromium nitride coated AISI D2 cold work tool steel against alumina ball realized at 0.1 m/s sliding speeds and under the loads of 2.5N, 5N and 10N. Steel samples were nitrided at 575°C for 8 h in the first step of the coating process, and then chromium nitride coating was performed thermo-reactive deposition technique (TRD) in a powder mixture consisting of ferro-chromium, ammonium chloride and alumina at 1000°C for 2 h. Nitro-chromized samples were characterized by X-Ray diffraction analysis (XRD), scanning electron microscopy (SEM), micro-hardness and ball on disk wear tests. The coating layer formed on the AISI D2 steel was compact and homogeneous. X-ray studies showed that the phase formed in the coated layer is Cr{sub 2}N. The depth of the layer was 8.15 µm. The average hardness of the layer was 2160±15 HV{sub 0.025}. For uncoated and chromium nitride materials, wear rate increased with increasing load. The results of friction coefficient and wear rate of the tested materials showed that the CrN coating presents the lowest results.

  6. Optimisation of GTAW parameters for the tensile strength of AISI 304 stainless steel welds using the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Ertan, Rukiye

    2012-07-01

    The influence of welding parameters, i. e. the welding current, root gap and the shielding gas flow rate, on the tensile strength of AISI 304 austenitic stainless steel welded with gas tungsten arc welding was investigated. To determine the optimum levels of the parameters, the Taguchi approach was used to increase the tensile strength. The results were analysed by investigating the variance by which welding parameters significantly affect the response. Mathematical models were developed to describe the influence of the selected parameters on the tensile strength. The results were confirmed by experiments. [German] Der Einfluss der Schweissparameter, d. h. der Schweissstromstaerke, des Wurzelspaltes und des Schutzgasdurchflusses, auf die Zugfestigkeit des WIG-geschweissten hochlegierten Stahles AISI 304 ist in der diesem Beitrag zugrunde liegenden Studie untersucht worden. Um die optimale Groesse der Parameter in Bezug auf eine Erhoehung der Zugfestigkeit zu bestimmen, wurde der Ansatz nach Taguchi gewaehlt. Die Ergebnisse wurden analysiert, indem die Varianz ermittelt wurde, mit der die Schweissparameter signifikant die Ergebnisse veraendern. Es wurden mathematische Modelle entwickelt, um den Einfluss der gewaehlten Parameter auf die Zugfestigkeit zu beschreiben. Die Ergebnisse wurden durch Experimente bestaetigt.

  7. Study on Surface Integrity of AISI 1045 Carbon Steel when machined by Carbide Cutting Tool under wet conditions

    Directory of Open Access Journals (Sweden)

    Tamin N. Fauzi

    2017-01-01

    Full Text Available This paper presents the evaluation of surface roughness and roughness profiles when machining carbon steel under wet conditions with low and high cutting speeds. The workpiece materials and cutting tools selected in this research were AISI 1045 carbon steel and canela carbide inserts graded PM25, respectively. The cutting tools undergo machining tests by CNC turning operations and their performances were evaluated by their surface roughness value and observation of the surface roughness profile. The machining tests were held at varied cutting speeds of 35 to 53 m/min, feed rate of 0.15 to 0.50 mm/rev and a constant depth of cut of 1 mm. From the analysis, it was found that surface roughness increased as the feed rate increased. Varian of surface roughness was suspected due to interaction between cutting speeds and feed rates as well as nose radius conditions; whether from tool wear or the formation of a built-up edge. This study helps us understand the effect of cutting speed and feed rate on surface integrity, when machining AISI 1045 carbon steel using carbide cutting tools, under wet cutting conditions.

  8. The effect of glutaraldehyde on the development of marine biofilms formed on surfaces of AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Tapper, R.C.; Smith, J.R.; Beech, I.B. [Univ. of Portsmouth (United Kingdom). School of Chemistry, Physics, and Radiography; Viera, M.R.; Guiamet, P.S.; Videla, H. [Univ. of La Plata (Argentina); Swords, C.L.; Edyvean, R.G.J. [Univ. of Sheffield (United Kingdom). Dept. of Mechanical and Process Engineering

    1997-08-01

    The effect of pre-conditioning polished and unpolished AISI 304 stainless steel surfaces with glutaraldehyde on the attachment, growth and morphology of an aerobic consortium of marine bacteria was investigated using total cell number counts, epifluorescence microscopy, Atomic Force Microscopy (AFM), Environmental Scanning Electron Microscopy (ESEM) and grazing-angle Fourier Transform Infrared (FTIR) spectroscopy. Both fully hydrated and dehydrated biofilms were studied using AFM and ESEM. Formation of the conditioning layer on steel surfaces from the culture medium, in the presence and absence of glutaraldehyde was monitored in-situ employing AFM and Grazing Angle FTIR spectroscopy. The influence of both surface area and surface energy upon the numbers of bacteria attached to polished and unpolished coupons was determined. This study has shown the influence of pretreatment of AISI 304 stainless steel with glutaraldehyde upon biofilm formation and has demonstrated the ability of AFM, ESEM and FTIR to be used as valuable tools for the in-situ investigation of the effect of biocides on bacterial biofilms.

  9. High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2

    Energy Technology Data Exchange (ETDEWEB)

    Prajitno, Djoko Hadi, E-mail: djokohp@batan.go.id; Syarif, Dani Gustaman, E-mail: djokohp@batan.go.id [Research Center for Nuclear Materials and Radiometry, Jl. Tamansari 71, Bandung 40132 (Indonesia)

    2014-03-24

    The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO{sub 2}. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe{sub 2}O{sub 3}. Minor element such as Cr{sub 2}O{sub 3} is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO{sub 2} appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

  10. Improving the Adhesion Resistance of the Boride Coatings to AISI 316L Steel Substrate by Diffusion Annealing

    Science.gov (United States)

    Campos-Silva, I.; Bernabé-Molina, S.; Bravo-Bárcenas, D.; Martínez-Trinidad, J.; Rodríguez-Castro, G.; Meneses-Amador, A.

    2016-09-01

    In this study, new results about the practical adhesion resistance of boride coating/substrate system formed at the surface of AISI 316 L steel and improved by means of a diffusion annealing process are presented. First, the boriding of AISI 316 L steel was performed by the powder-pack method at 1173 K with different exposure times (4-8 h). The diffusion annealing process was conducted on the borided steels at 1273 K with 2 h of exposure using a diluent atmosphere of boron powder mixture. The mechanical behavior of the boride coating/substrate system developed by both treatments was established using Vickers and Berkovich tests along the depth of the boride coatings, respectively. Finally, for the entire set of experimental conditions, the scratch tests were performed with a continuously increasing normal force, in which the practical adhesion resistance of the boride coating/substrate system was represented by the critical load. The failure mechanisms developed over the surface of the scratch tracks were analyzed; the FeB-Fe2B/substrate system exhibited an adhesive mode, while the Fe2B/substrate system obtained by the diffusion annealing process showed predominantly a cohesive failure mode.

  11. Wear behavior of the surface alloyed AISI 1020 steel with Fe-Nb-B by TIG welding technique

    Energy Technology Data Exchange (ETDEWEB)

    Kilinc, B., E-mail: bkilinc@sakarya.edu.tr; Durmaz, M.; Abakay, E. [Department of Metallurgical and Materials Engineering, Institute of Arts and Sciences, SakaryaUniversity, Esentepe Campus, 54187Sakarya (Turkey); Sen, U.; Sen, S. [Department of Metallurgical and Materials Engineering, Engineering Faculty, Sakarya University, Esentepe Campus, 54187 Sakarya (Turkey)

    2015-03-30

    Weld overlay coatings also known as hardfacing is a method which involves melting of the alloys and solidification for applied coatings. Recently hardfacing by welding has become a commonly used technique for improvement of material performance in extreme (high temperature, impact/abrasion, erosion, etc.) conditions.In the present study, the coatings were produced from a mixture of ferrous niobium, ferrous boron and iron powders in the ranges of -45µm particle size with different ratio. Fe{sub 12}Nb{sub 5}B{sub 3} and Fe{sub 2}NbBalloys were coated on the AISI 1020 steel surface by TIG welding. The phases formed in the coated layer are Fe{sub 2}B, NbB{sub 2}, NbFeB and Fe0,2 Nb{sub 0,8} phases. The hardness of the presence phases are changing between 1689±85 HV{sub 0.01}, and 181±7 HV{sub 0.1}. Microstructural examinations were realized by optical and scanning electron microscopy. The wear and friction behaviors of Fe{sub 12}Nb{sub 5}B{sub 3} and Fe2NbB realized on the AISI 1020 steel were investigated by the technique of TIG welding by using ball-on-disk arrangement against alumina ball.

  12. Resistance Spot Weldability of Dissimilar Materials: BH180-AISI304L Steels and BH180-IFT123 Steels

    Institute of Scientific and Technical Information of China (English)

    Fatih Hayat

    2011-01-01

    In this study, resistance spot weldability of 180 grade bake hardening steel (BH180), 7123 grade interstitial free steel (IF7123) and 304 grade austenitic stainless steel (AISI304L) with each other was investigated. In the joining process, electrode pressure and weld current were kept constant and six different weld time were chosen. Microstructure, microhardness, tensile-shear properties and fracture types of resistance spot welded joints were examined. In order to characterize the metallurgical structure of the welded joint, the microstructural profile was developed, and the relationship between mechanical properties and microstructure was determined. The change of weld time, nugget diameter, the HAZ (heat affected zone) width and the electrode immersion depth were also investigated. Welded joints were examined by SEM (scanning electron microscopy) images of fracture surface. As a result of the experiment, it was determined that with increasing weld time, tensile shear load bearing capacity (TLBC) increased with weld time up to 25 cycle and two types of tearing occurred. It was also determined that while the failure occurred from IF side at the BHIS0+IF7123 joint, it occurred from the BH180 side at the BHIS0+AISI304L joint.

  13. Predicción del desgaste del flanco de la herramienta de corte durante el torneado en seco de alta velocidad para piezas de acero AISI 316L en la industria minera

    Directory of Open Access Journals (Sweden)

    Yusimit K. Zamora-Hernández

    2015-07-01

    Full Text Available Se realizó un estudio experimental sobre la influencia de los parámetros de corte en el torneado del acero inoxidable AISI 316L con insertos recubiertos de TiCN, Al2O3, TiN. Un microscopio electrónico de barrido fue utilizado para medir y analizar el desgaste de las herramientas de corte. Los resultados fueron comparados utilizando el análisis de varianza y el análisis de regresión múltiple para describir la relación entre el desgaste del flanco de las herramientas de corte, el tiempo de maquinado y el avance de corte, obteniéndose las ecuaciones de los modelos ajustados. La investigación demostró el efecto significativo del avance y del tiempo de maquinado en el desgaste del flanco. El inserto de tres capas no sobrepasó el criterio de fin de vida del desgaste, mientras que el inserto de una capa sufrió un desgaste elevado para la mayor velocidad de corte. El desgaste del flanco tuvo mejor comportamiento para el avance de 0,08 mm/rev en todas las velocidades empleadas en este estudio. Los errores medios absolutos no superaron el 15 %.

  14. Microestructura de una unión disímil AISI 321 y una aleación A 351 grado HK-40 obtenida mediante soldadura manual por arco eléctrico

    Directory of Open Access Journals (Sweden)

    Reilis Fuentes-Guilarte

    2016-05-01

    Full Text Available El objetivo fue establecer el comportamiento microestructural de una unión disímil de acero inoxidable austenítico AISI 321 y de la aleación A 351 grado HK 40 obtenida por fundición mediante soldadura manual por arco eléctrico y electrodos revestidos del tipo E 309 L-16. La estructura ferrita–austeníta que se forma en la unión del acero con la aleación es resultado del elevado contenido de carbono de la segunda. La baja velocidad de enfriamiento del cordón de soldadura revela ausencia de discontinuidades en el retículo cristalino de la zona afectada térmicamente y atenúa la formación de carburos de cromo del tipo Cr23C6, que puede formar la aleación A 351 grado HK 40 durante la difusión del volumen de fracción en masa del cromo.

  15. INFLUENCIA DE LA NITRURACIÓN POR PLASMA SOBRE EL COMPORTAMIENTO A LA CORROSIÓN Y LA ADHESIÓN DE RECUBRIMIENTOS DLC SOBRE ACERO INOXIDABLE AISI 420

    Directory of Open Access Journals (Sweden)

    Jorge N. Pecina

    2016-01-01

    Full Text Available En este trabajo se estudió el comportamiento a la corrosió n y la adhesión de dos rec ubrimientos DLC (“Diamond Like Carbon ” , “Soft” y “Hard”, depositados por PACVD (“Plasma Assisted Chemical Vapour Deposition” sobre acero AISI 420, templado y revenido y /o nitrurado por plasma . Se analizaron por espectroscopía Raman y midió dureza en superficie. Se observó la microestructura por OM y SEM. Se realizaron pruebas de adhesión con indentación Rockwell C . S e practicaron ensayos de Niebla Salina e inmersión en HCl . Los DLC “ Soft ” presentaron una dureza de 5 00 HV y un espesor de 2 0 μm , mientras que los “ Hard ” tuvieron 1400 HV y 2 ,5 μm. Ambos recubrimientos presentaron bajo coeficiente de fricción y buena adhesión sobre el sustrato nitrurado . También presentaron buena resistencia a la corrosión atmosférica. En HCl el DLC retardó la degradación que se presentó rápidamente en las muestras sin recubrir.

  16. Microstructure, mechanical properties and chemical degradation of brazed AISI 316 stainless steel/alumina systems

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, O.C. [Instituto Superior de Engenharia do Porto (ISEP), Rua Dr. Antonio Bernardino de Almeida 431, 4200-072 Porto (Portugal)], E-mail: omp@isep.ipp.pt; Barbosa, M.A. [Instituto de Engenharia Biomedica (INEB), Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Roberto Frias s/n, 4200-465 Porto (Portugal)

    2008-05-15

    The main aims of the present study are simultaneously to relate the brazing parameters with: (i) the correspondent interfacial microstructure, (ii) the resultant mechanical properties and (iii) the electrochemical degradation behaviour of AISI 316 stainless steel/alumina brazed joints. Filler metals on such as Ag-26.5Cu-3Ti and Ag-34.5Cu-1.5Ti were used to produce the joints. Three different brazing temperatures (850, 900 and 950 deg. C), keeping a constant holding time of 20 min, were tested. The objective was to understand the influence of the brazing temperature on the final microstructure and properties of the joints. The mechanical properties of the metal/ceramic (M/C) joints were assessed from bond strength tests carried out using a shear solicitation loading scheme. The fracture surfaces were studied both morphologically and structurally using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The degradation behaviour of the M/C joints was assessed by means of electrochemical techniques. It was found that using a Ag-26.5Cu-3Ti brazing alloy and a brazing temperature of 850 deg. C, produces the best results in terms of bond strength, 234 {+-} 18 MPa. The mechanical properties obtained could be explained on the basis of the different compounds identified on the fracture surfaces by XRD. On the other hand, the use of the Ag-34.5Cu-1.5Ti brazing alloy and a brazing temperature of 850 deg. C produces the best results in terms of corrosion rates (lower corrosion current density), 0.76 {+-} 0.21 {mu}A cm{sup -2}. Nevertheless, the joints produced at 850 deg. C using a Ag-26.5Cu-3Ti brazing alloy present the best compromise between mechanical properties and degradation behaviour, 234 {+-} 18 MPa and 1.26 {+-} 0.58 {mu}A cm{sup -2}, respectively. The role of Ti diffusion is fundamental in terms of the final value achieved for the M/C bond strength. On the contrary, the Ag and Cu distribution along the

  17. Transformaciones Microestructurales en Soldaduras Disímiles de Acero Inoxidable Austenítico con Acero Inoxidable Ferrítico

    Directory of Open Access Journals (Sweden)

    Sara María Aguilar-Sierra

    2015-03-01

    Full Text Available En este trabajo se estudian los fenómenos metalúrgicos que ocurren en la soldadura SMAW de un acero inoxidable ferrítico AISI 430 con un acero inoxidable austenítico AISI 316L. Para el estudio se utilizaron dos tipos de electrodos: austenítico AWS E309L y dúplex AWS E2209-16, ambos con un diámetro de 3,2 mm. Las uniones soldadas se realizaron con un solo pase y se variaron simultáneamente la corriente y la velocidad de soldadura; las condiciones fueron 49 A y 2,4 mm.s–1como valores bajos y 107 A y 4,3 mm.s–1como valores altos. Se evaluó la influencia del tipo de electrodo y de los parámetros de soldadura en la evolución microestructural de las zonas afectadas por el calor y de las zonas de fusión, encontrando diferencias en la morfología y cantidad de ferrita delta para todas las condiciones estudiadas. Se evidenció crecimiento y refinación de grano ferrítico y formación de martensita en la zona afectada por el calor del metal base ferrítico. Se evaluó también la resistencia a la tensión hallando similitudes en todas las soldaduras.

  18. Surface fatigue life of carburized and hardened M50NiL and AISI 9310 spur gears and rolling-contact test bars

    Science.gov (United States)

    Townsend, Dennis P.; Bamberger, Eric N.

    1989-01-01

    Spur gear endurance tests and rolling-element surface tests were conducted to investigate vacuum-induction-melted, vacuum-arc-melted (VIM-VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling-contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm (3.5 in.). Gear test conditions were an inlet oil temperature of 320 K (116 F), and outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench rolling-element fatigue tests were conducted at ambient temperatures with a bar speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPA (700 ksi). The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling-contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR M50NiL material was shown to have good resistance to fracture through a fatigue spall and to have fatigue life far superior to that of both VIM-VAR and VAR AISI 9310 gears and rolling-contact bars.

  19. Análisis de la deformabilidad del acero inoxidable AISI 304 DDQ en condiciones multiaxiales de embutición. Evaluación de la influencia de la acritud inicial

    Directory of Open Access Journals (Sweden)

    Ferrer, C.

    2010-10-01

    Full Text Available The deep drawing formability of a material is established as a function of standard indexes, as strength coefficient and anisotropy coefficient. But these indexes are determined in different conditions to those that take place in the forming process. The simulative assays do not separate the actions due to the different variables that work in the process, as for example, the rolling direction. In the present work a test that uses a wedge shape die is considered in order to obtain the strength and anisotropy coefficients as a function of rolling direction. This way, the assays are carried out under a tensile-biaxial compression stress state similar to that one taking place in the flange zone in deep drawing. The experimented material is a deep drawing quality stainless steel AISI 304. The influence of initial strengthened states, rolling and uniaxial tensile on the steel behaviour are also studied. The results permits the authors establish the validity of the assay from the point of view of the strains produced in the sheet. The initial strain has a higher effect on the material than that one obtained from the tensile-biaxial of the state than the tensile-biaxial compression causes. The anisotropy coefficient changes with the strain for the sheet rolling direction.La embutibilidad de un material se establece en función de indicadores normalizados, como son los índices de anisotropía y de acritud, que suelen determinarse en condiciones diferentes a las de conformado. Por otro lado, también es muy frecuente determinar la embutibilidad de los materiales mediante ensayos simulativos, que no separan las diferentes variables que actúan en el proceso como, por ejemplo, la dirección de laminación. En el presente trabajo se utiliza un ensayo con matriz en forma de cuña para determinar el coeficiente de endurecimiento y de anisotropía en función de la dirección de laminación para diferentes deformaciones en condiciones similares a las de tracci

  20. Effects of surface modification of thin wires of AISI 302 stainless steel by electrolytic plasma on its mechanical properties; Efecto de la modificacion superficial de alambres delgados de acero inoxidable AISI 302 mediante plasma electrolitico sobre sus propiedades mecanicas

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, A.; Camurri, C.; Carrasco, C.; Soldera, F.

    2012-07-01

    In this work different tests using electrolytic plasma (EP) on thin wires of stainless steel AISI 302 in an inert solution were performed. Tensile tests were carried out in order to measure changes in the mechanical strength of the samples; moreover, both the morphological and microstructural changes also were evaluated. It was found that after 10 s of the application of EP, the samples surface was uniformly covered by nodules-like and craters similar to those found in the melting and cooling periods of EP. The results show a significant surface grain refinement, leading to crystalline arrangements with sizes less than 200 nm and also an increase in the samples tensile strength of at least 57 % respect to steel base. (Author) 14 refs.

  1. Influence of copper and tin addition on pitting corrosion behaviour of AISI 304 Strainless Steel; Efecto de la adicion de cobre y estano en el comportamiento a la corrosion por picadura de acero inoxidable AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M. C.; Botella, J.; Matres, V.; Viejo, F.; Carboneras, M.; Arrabal, R.

    2004-07-01

    The influence of copper and tin addition on the pitting corrosion resistance of AISI 304 stainless steel in 3.5% NaCl at 20 degree centigree has been studied using potenciodinamic and cyclic polarization. From that study the effect of alloying elements (Cu and Sn) in the corrosion, pitting and re passivation potentials were determined. The effect of copper and tin on the critical pitting temperature (CPT) was determined by i{sub c}orr-time-temperature curves. The influence of these alloying elements in FeCl{sub 3} under ASTM G48-00 norm was also studied. The addition of copper favours the nucleation of pits. The addition of tin slightly improves the corrosion resistance. The synergic effect of Cu-Sn was positive at low concentrations. (Author) 10 refs.

  2. Applications of the essay at slow deformation velocity in pipes of stainless steel AISI-304; Aplicaciones del ensayo a velocidad de deformacion lenta en tuberias de acero inoxidable AISI-304

    Energy Technology Data Exchange (ETDEWEB)

    Zamora R, L.; Mora R, T. De la [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    Nowadays is carried out research related with the degradation mechanisms of structures, systems and/or components in the nuclear power plants, since many of the involved processes are those responsible for the dependability of these, of the integrity of the components and of the aspects of safety. The purpose of this work, was to determine the grade of susceptibility to the corrosion of a pipe of Austenitic stainless steel AISI 304, in a solution of Na CI (3.5%) to the temperatures of 60 and 90 C, in two different thermal treatments - 1. - Sensitive 650 C by 4 hours and cooled in water. 2. Solubilized to 1050 C by 1 hour and cooled in water.

  3. Effects of nitrogen and pulsed mean welding current in AISI 316 austenitic stainless steel solidification cracks; Efecto del nitrogeno y la corriente media pulsada de soldadura en la formacion de grietas de solidificacion en aceros inoxidables AISI 316L

    Energy Technology Data Exchange (ETDEWEB)

    Trevisan, R. E.; Braga, E.; Fals, H. C.

    2002-07-01

    An analysis of the influence of nitrogen concentration in the weld zone and the pulsed mean welding current in the solidification crack formation is presented in this paper. The AISI 316L austenitic stainless steel was employed as the metal base. The welding was done using CC+ pulsed flux cored are welding process and AWS E316L wire type. The tests were conducted using CO{sub 2} shielding gas with four different nitrogen levels (0,5; 10 and 15%) in order to induce different nitrogen weld metal concentrations. The pulsed mean welding current was varied in three levels and the. Transvarestraint tangential strain test was fixed of 5%. The results showed that the solidification cracking decreased as the pulsed mean welding current increase. It was also verified that an increase of the weld zone nitrogen level was associated with a decrease in both the total length of solidification crack and the amount of {delta} ferrite. (AUthor) 20 refs.

  4. Comparative study of AISI M3:2 high speed steel produced through different techniques of manufacturing; Estudo comparativo de acos rapidos AISI M3:2 produzidos por diferentes processos de fabricacao

    Energy Technology Data Exchange (ETDEWEB)

    Araujo Filho, Oscar Olimpio de

    2006-07-01

    In this work AISI M3:2 high speed steels obtained through different techniques of manufacturing, submitted to the same heat treatment procedure were evaluated by measuring their mechanical properties of transverse rupture strength and hardness. Sinter 23 obtained by hot isostatic pressing (HIP), VWM3C obtained by the conventional route and a M3:2 high speed steel obtained by cold compaction of water atomized powders and vacuum sintered with and without the addition of a small quantity of carbon were evaluated after the same heat treatment procedure. The vacuum sintered M3:2 high speed steel can be an alternative to the more expensive high speed steel produced by hot isostatic pressing and with similar properties presented by the conventional one. The characterization of the vacuum sintered M3:2 high speed steel was performed by measuring the densities of the green compacts and after the sintering cycle. The sintering produced an acceptable microstructure and densities near to the theoretical. The transverse rupture strength was evaluated by means of three point bending tests and the hardness by means of Rockwell C and Vickers tests. The technique of scanning electronic microscopy (SEM) was used to evaluate the microstructure and to establish a relation with the property of transverse rupture strength. The structure was determined by means of X-ray diffraction (XRD) patterns and the retained austenite was detected to all the conditions of heat treatment. The main contribution of this work is to establish a relation between the microstructure and the mechanical property of transverse rupture strength and to evaluate the AISI M3:2 vacuum sintered high speed steel as an alternative to the similar commercial high speed steels. (author)

  5. Characterization of Plasma Nitrocarburized Layers Produced on AISI 316L Stainless Steel%AISI 316L不锈钢等离子氮碳共渗层的表征

    Institute of Scientific and Technical Information of China (English)

    L. C. Casteletti; F. A. P. Fernandes; A. Lombardi-Neto; C. A. Picon; G. Tremiliosi-Filho; G. E. Totten

    2009-01-01

    Hardness and consequently wear resistance of austenitic stainless steel can be highly increased, without loosing corrosion resistance by producing plasma nitrocarburizing surface layers. In this work, a AISI 316L stainless steel plasma nitrocarburized at 450℃, and the obtained layers were characterized by optical microscopy, micro-hardness and micro-wear tests. It was verified that the layer is composed by chromium nitrides precipitates and essentially expanded austenite nitrogen rich and with hardness around 850 HV. The total average thickness of the layer was about 45 μm, presenting good uniformity. Its wear resistance was much higher than that of the sub-strate.%奥氏体不锈钢通过等离子氮碳共渗可显著提高其表面硬度,从而提高耐磨性而又不损害其抗腐蚀性能.本文采用光学显微镜、显微硬度和微磨损试验对经于450℃等离子氮碳共渗的AISI 316L不锈钢和所获得的渗层进行了表征.结果证明,等离子氮碳共渗层由氮化铬析出相和富氮奥氏体基体组成,其硬度约850 HV;渗层总深度平均约为45 μm,且很均匀;渗层的耐磨性大大高于基体.

  6. Effect of low temperature plasma hardening treatment on microstructure and properties of AISI 420 stainless steel%低温离子硬化处理对 AISI 420不锈钢组织与性能的影响

    Institute of Scientific and Technical Information of China (English)

    杜威; 赵程

    2014-01-01

    研究了低温离子渗氮、离子氮碳共渗和离子渗碳硬化处理对AISI 420马氏体不锈钢的显微组织、表面硬度、耐蚀性、耐磨性的影响。结果表明,离子渗氮、氮碳共渗和离子渗碳处理都可提高马氏体不锈钢的表面硬度;经不同工艺处理后的试样,除500℃×4 h渗氮工艺外,其他不锈钢试样表面的耐蚀性均未出现明显降低,当渗氮温度过高(500℃)时,由于CrN的析出使得渗氮层的耐蚀性显著下降;磨损试验的结果表明,离子渗碳处理后硬化层的耐磨性最佳。%Effect of low temperature plasma nitriding , nitrocarburizing and carburizing on microstructure , surface hardness , corrosion resistance and wear resistance of AISI 420 martensitic stainless steel was investigated . The results show that plasma nitriding , nitrocarburizing and carburizing process can increase the surface hardness .There is no significantly decrease to the corrosion resistance on the surface of Stainless steel treated by different treatment processes except of plasma nitriding at 500℃for 4 h.If the nitriding temperature is higher than 500℃, the corrosion resistance will significantly decline due to the precipitation of CrN .The wear results show that hardened layer of plasma carburizing sample has the best wear resistance .

  7. Educar con significado o con sentido

    Directory of Open Access Journals (Sweden)

    José Joaquín García García

    2017-01-01

    Full Text Available Hoy día, tres tendencias influyen directamente en la conformación de la escuela. En primer lugar, el afán de encontrar la esencia de todo encumbró a la razón e hizo de la racionalidad el único valor a defender en las aulas. En segundo lugar, el sistema capitalista hizo lo mismo con aquello que tiene valor de uso y valor de cambio, es decir, con la mercancía, validando solo lo que puede tener una utilidad económica conocida o posible. Esto convirtió a la educación en un proceso para certificar y ganar dinero, desdibujando así su intención de formar personas. Finalmente, la visión masculina y eurocéntrica con su locura por quererlo dominar todo, y de pensar que el hombre era el dueño del planeta e inclusive la vida y el destino de los otros hombres, mutiló culturas y eliminó a la naturaleza de los currículums en los centros educativos.

  8. Comparison of Roller Burnishing Method with Other Hole Surface Finishing Processes Applied on AISI 304 Austenitic Stainless Steel

    Science.gov (United States)

    Akkurt, Adnan

    2011-08-01

    Component surface quality and selection of the optimum material are the main factors determining the performance of components used in machine manufacturing. The level of hole surface quality can be evaluated by the measurements regarding surface roughness, micro-hardness, and cylindricity. In this study, data had been obtained for different hole drilling methods. The characteristics of materials obtained after applications were compared for different hole-finishing processes to identify best hole drilling method. AISI 304 austenitic stainless steel material was used. Surface finishing of holes were performed using drilling, turning, reaming, grinding, honing, and roller burnishing methods. The results of the study show that the roller burnishing method gives the best results for mechanical, metallurgical properties, and hole surface quality of the material. On the other hand, the worst characteristics were obtained in the drilling method.

  9. Experimental Determination of Temperature During Rotary Friction Welding of AA1050 Aluminum with AISI 304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Eder Paduan Alves

    2012-03-01

    Full Text Available The purpose of this study was the temperature monitoring at bonding interface during the rotary friction welding process of dissimilar materials: AA1050 aluminum with AISI 304 stainless steel. As it is directly related to the mechanical strenght of the junction, its experimental determination in real time is of fundamental importance for understanding and characterizing the main process steps, and the definition and optimization of parameters. The temperature gradients were obtained using a system called Thermocouple Data-Logger, which allowed monitoring and recording data in real-time operation. In the graph temperature versus time obtained, the heating rates, cooling were analyzed, and the maximum temperature was determined that occurred during welding, and characterized every phases of the process. The efficiency of this system demonstrated by experimental tests and the knowledge of the temperature at the bonding interface open new lines of research to understand the process of friction welding.

  10. Effect of copper on the formation of strain-induced martensite in two austenitic stainless steels AISI 304

    Energy Technology Data Exchange (ETDEWEB)

    Gilapa, Leonidas Cayo Mamani, E-mail: leonidas@ifsc.edu.br [Instituto Federal de Santa Catarina, Rua Pavão, 1337, Bairro Costa e Silva, Joinville, SC CEP 89220-200 (Brazil); Oliveira, Carlos Augusto Silva de, E-mail: carlos.a@ufsc.br [Universidade Federal de Santa Catarina, Campus Universitário Reitor João David Ferreira Lima, Trindade, Florianópolis, SC CEP 88040-970 (Brazil); Silva, Manoel Ribeiro da, E-mail: mrsilva@unifei.edu.br [Universidade Federal de Itajubá, Instituto de Ciências, Itajubá (Brazil)

    2015-01-12

    The transformation of strain-induced martensite in two metastable austenitic stainless steels, AISI 304, with the same basic composition and concentrations of Cu variables was characterized by transmission electron microscopy and magnetic measurements. The deformations to induce the formation of martensite were performed using the test of conformability with Nakajima tooling at room temperature. The results obtained for the various samples showed that the steel with lower content of Cu presented higher degree of magnetization. Also it was observed that the martensite magnetic α′ and paramagnetic ε are formed at the intersection of dislocation, in the grain boundary, inside and at the edge of twinned and the stacking faults in the austenite.

  11. Comparision of Cut Surface Properties Obtained from AISI 1030 Steel by Abresive Water Jet and by Other Methodologies

    Directory of Open Access Journals (Sweden)

    ADNAN AKKURT

    2009-02-01

    Full Text Available With the development in cutting operation, the surface properties which get from the the finishing operation and preparation to manifacture applications have a great importance.Generally the variation features of material, the edge cutting deformation, surface properties and the geometry of the canal characterize the processing quality in the cutting methods.In a cutting operation the aim is to get the cut surface in a very short time with high quality.The answer is searching for the question, which technique for which material must be use to get a good efficiency.In this study the aim was to cut the material AISI 1030, which is used very frequently in manifacture industry, with very common methods and to get and evaluate effects of results on mechanic and metallurgic properties of material.So the result of this study is the method in cutting with ASJ is the most efficient and with oxygen is least efficient.

  12. Normalizing effect on fatigue crack propagation at the heat-affected zone of AISI 4140 steel shielded metal arc weldings

    Directory of Open Access Journals (Sweden)

    B. Vargas-Arista

    2013-01-01

    Full Text Available The fractography and mechanical behaviour of fatigue crack propagation in the heat-affected zone (HAZ of AISI 4140 steel welded using the shielded metal arc process was analysed. Different austenitic grain size was obtained by normalizing performed at 1200 °C for 5 and 10 hours after welding. Three point bending fatigue tests on pre-cracked specimens along the HAZ revealed that coarse grains promoted an increase in fatigue crack growth rate, hence causing a reduction in both fracture toughness and critical crack length, and a transgranular brittle final fracture with an area fraction of dimple zones connecting cleavage facets. A fractographic analysis proved that as the normalizing time increased the crack length decreased. The increase in the river patterns on the fatigue crack propagation in zone II was also evidenced and final brittle fracture because of transgranular quasicleavage was observed. Larger grains induced a deterioration of the fatigue resistance of the HAZ.

  13. Characteristics and Modification of Non-metallic Inclusions in Titanium-Stabilized AISI 409 Ferritic Stainless Steel

    Science.gov (United States)

    Kruger, Dirk; Garbers-Craig, Andrie

    2017-02-01

    This study describes an investigation into the improvement of castability, final surface quality and formability of titanium-stabilized AISI 409 ferritic stainless steel on an industrial scale. Non-metallic inclusions found in this industrially produced stainless steel were first characterized using SEM-EDS analyses through the INCA-Steel software platform. Inclusions were found to consist of a MgO·Al2O3 spinel core, which acted as heterogeneous nucleation site for titanium solubility products. Plant-scale experiments were conducted to either prevent the formation of spinel, or to modify it by calcium treatment. Modification to spherical dual-phase spinel-liquid matrix inclusions was achieved with calcium addition, which eliminated submerged entry nozzle clogging for this grade. Complete modification to homogeneous liquid calcium aluminates was achieved at high levels of dissolved aluminum. A mechanism was suggested to explain the extent of modification achieved.

  14. Application of Deep Cryogenic Treatment to Uncoated Tungsten Carbide Inserts in the Turning of AISI 304 Stainless Steel

    Science.gov (United States)

    Özbek, Nursel Altan; Çİçek, Adem; Gülesİn, Mahmut; Özbek, Onur

    2016-12-01

    This study investigated the effects of deep cryogenic treatment (DCT) on the wear performance of uncoated tungsten carbide inserts. AISI 304 austenitic stainless steel, widely used in industry, was selected as the workpiece material. Cutting experiments showed that the amount of wear significantly increased with increasing cutting speed. In addition, it was found that DCT contributed to the wear resistance of the turning inserts. The treated turning inserts were less worn by 48 and 38 pct in terms of crater wear and notch wear, respectively, whereas they exhibited up to 18 pct superior wear performance in terms of flank wear. This was attributed to the precipitation of new and finer η-carbides and their homogeneous distribution in the microstructure of the tungsten carbide material after deep cryogenic treatment. Analyses via image processing, hardness measurements, and SEM observations confirmed these findings.

  15. Martensite transformation induced by deformation and its phase electrochemical behavior for stainless steels AISI 304 and 316L

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The martensite transformation induced by tensile elongation and its effect on the behavior of phase electrochemistry of AISI 304 and 316L in 3.5% NaCl solution were studied. The results show that the content of ((-martensite in stainless steel 304 increases with the true strain. As ((-martensite content increased, free corrosion potential and pitting potential of stainless steel 304 in 3.5% NaCl solution appeared the change trend of a minimum. It was also found that pitting nucleated preferentially at the phase interfaces between martensite and austenite. There existed apparent difference between electrochemical properties of austenite and of martensite for stainless steel 304 and 316L in 3.5% NaCl solution.

  16. Application of Deep Cryogenic Treatment to Uncoated Tungsten Carbide Inserts in the Turning of AISI 304 Stainless Steel

    Science.gov (United States)

    Özbek, Nursel Altan; Çİçek, Adem; Gülesİn, Mahmut; Özbek, Onur

    2016-09-01

    This study investigated the effects of deep cryogenic treatment (DCT) on the wear performance of uncoated tungsten carbide inserts. AISI 304 austenitic stainless steel, widely used in industry, was selected as the workpiece material. Cutting experiments showed that the amount of wear significantly increased with increasing cutting speed. In addition, it was found that DCT contributed to the wear resistance of the turning inserts. The treated turning inserts were less worn by 48 and 38 pct in terms of crater wear and notch wear, respectively, whereas they exhibited up to 18 pct superior wear performance in terms of flank wear. This was attributed to the precipitation of new and finer η-carbides and their homogeneous distribution in the microstructure of the tungsten carbide material after deep cryogenic treatment. Analyses via image processing, hardness measurements, and SEM observations confirmed these findings.

  17. Coated carbide drill performance under soluble coconut oil lubricant and nanoparticle enhanced MQL in drilling AISI P20

    Science.gov (United States)

    Jamil, N. A. M.; Azmi, A. I.; Fairuz, M. A.

    2016-02-01

    This research experimentally investigates the performance of a TiAlN coated carbide drill bit in drilling AISI P20 through two different kinds of lubricants, namely; soluble coconut oil (SCO) and nanoparticle-enhanced coconut oil (NECO) under minimum quantity lubrication system. The tool life and tool wear mechanism were studied using various cutting speeds of 50, 100 and 150 m/min with a constant feed of 0.01 mm/rev. Since the flank wear land was not regular along the cutting edge, the average flank wear (VB) was measured at several points using image analysis software. The drills were inspected using a scanning electron microscope to further elucidate the wear mechanism. The result indicates that drilling with the nanoparticle- enhanced lubricant was better in resisting the wear and improving the drill life to some extent

  18. A study of corrosion inhibition of steel AISI-SAE 1020 in CO2-brine using surfactant Tween 80

    Science.gov (United States)

    Cedeño, M. L.; L, E. Vera; Pineda T, Y.

    2017-01-01

    Surfactant inhibitors also called active surface agents are molecules composed of a polar hydrophilic group and a non-polar hydrophobic group, with characteristics of adsorption on metal surfaces, high efficiency of inhibiting, low price, low toxicity and easy production. In this work, the corrosion inhibition was study by CO2 steel AISI-SAE 1020 with the addition of 0.01M Tween 80 surfactant to a brine solution (3% NaCl). Electrochemical Impedance Spectroscopy and potentiodynamic polarization testing investigated the phenomenon. The results revealed that the surfactant studied acts as an excellent corrosion inhibitor and inhibition efficiency (E%) increases with increasing fluid velocity. The morphology of the steel surface after exposure to the solution of 3% NaCl with and without surfactant indicates the inhibition phenomenon is due to the adsorption of the surfactant molecules, which insulate the surface of the corrosive medium and reduces the attack surficial.

  19. Corrosion resistance of multilayer hybrid sol-gel coatings deposited on the AISI 316L austenitic stainless steel

    Science.gov (United States)

    Caballero, Y. T.; Rondón, E. A.; Rueda, L.; Hernández Barrios, C. A.; Coy, A.; Viejo, F.

    2016-02-01

    In the present work multilayer hybrid sol-gel coatings were synthesized on the AISI 316L austenitic stainless steel employed in the fabrication of orthopaedic implants. Hybrid sols were obtained from a mixture of inorganic precursor, TEOS, and organic, GPTMS, using ethanol as solvent, and acetic acid as catalyst. The characterization of the sols was performed using pH measurements, rheological tests and infrared spectroscopy (FTIR) for different ageing times. On the other hand, the coatings were characterized by scanning electron microscopy (SEM), while the corrosion resistance was evaluated using anodic potentiodynamic polarization in SBF solution at 37±2°C. The results confirmed that sol-gel synthesis employing TEOS-GPTMS systems produces uniform and homogeneous coatings, which enhanced the corrosion resistance with regard to the parent alloy. Moreover, corrosion performance was retained after applying more than one layer (multilayer coatings).

  20. TEM and AES investigations of the natural surface nano-oxide layer of an AISI 316L stainless steel microfibre.

    Science.gov (United States)

    Ramachandran, Dhanya; Egoavil, Ricardo; Crabbe, Amandine; Hauffman, Tom; Abakumov, Artem; Verbeeck, Johan; Vandendael, Isabelle; Terryn, Herman; Schryvers, Dominique

    2016-11-01

    The chemical composition, nanostructure and electronic structure of nanosized oxide scales naturally formed on the surface of AISI 316L stainless steel microfibres used for strengthening of composite materials have been characterised using a combination of scanning and transmission electron microscopy with energy-dispersive X-ray, electron energy loss and Auger spectroscopy. The analysis reveals the presence of three sublayers within the total surface oxide scale of 5.0-6.7 nm thick: an outer oxide layer rich in a mixture of FeO.Fe2 O3 , an intermediate layer rich in Cr2 O3 with a mixture of FeO.Fe2 O3 and an inner oxide layer rich in nickel.

  1. Experimental investigations on effects of frequency in ultrasonically-assisted end-milling of AISI 316L: A feasibility study.

    Science.gov (United States)

    Maurotto, A; Wickramarachchi, C T

    2016-02-01

    The effects of frequency in ultrasonic vibration assisted milling (UVAM) with axial vibration of the cutter is investigated in this paper. A series of face-mill experiment in dry conditions were conducted on AISI 316L, an alloy of widespread use in industry. The finished surfaces roughness were studied along with basic considerations on tool wear for both conventional milling and an array of frequencies for UVAM (20–40–60 kHz) in a wide range of cutting conditions. Surface residual stresses and cross-cut metallographic slides were used to investigate the hidden effects of UVAM. Experimental results showed competitive results for both surface roughness and residual stress in UVAM when compared with conventional milling especially in the low range of frequency with similar trend for tool wear.

  2. Tribological behavior of AISI302 austenitic stainless steel modified by elevated temperature nitrogen plasma immersion ion implantation

    Institute of Scientific and Technical Information of China (English)

    JIANG Shao-qun; MA Xin-xin; SUN Yue

    2004-01-01

    AISI302 stainless steel samples were modified by elevated temperature nitrogen plasma immersion ion implantation at temperature ranging from 330 ℃ to 450 ℃. The tribological behaviors of the implanted layers of the samples were investigated. The samples were characterized by Auger electron spectroscopy (AES), glancing angle X-ray diffraction (GXRD), and nanoindentation. The results show that the implantation temperature plays an important rule on the microstructure and surface properties of the implanted layers. The thickness of the modified layer implanted at 390 ℃ is about 9 μm. It is improved about two orders compared with that of the implanted at room temperature. The surface nanohardness and the wear resistance of elevated temperature implanted layers increase significantly, and the friction coefficient decreases obviously in comparison with the unimplanted one. These data suggests that the improvement results from the formation of new phases such as ε-(Fe, Cr, Ni)2+xN, or noncrystal phase.

  3. Influence of dissolved hydrogen on the fatigue crack growth behaviour of AISI 4140 steel

    Science.gov (United States)

    Ramasagara Nagarajan, Varun

    Many metallic structural components come into contact with hydrogen during manufacturing processes or forming operations such as hot stamping of auto body frames and while in service. This interaction of metallic parts with hydrogen can occur due to various reasons such as water molecule dissociation during plating operations, interaction with atmospheric hydrogen due to the moisture present in air during stamping operations or due to prevailing conditions in service (e.g.: acidic or marine environments). Hydrogen, being much smaller in size compared to other metallic elements such as Iron in steels, can enter the material and become dissolved in the matrix. It can lodge itself in interstitials locations of the metal atoms, at vacancies or dislocations in the metallic matrix or at grain boundaries or inclusions (impurities) in the alloy. This dissolved hydrogen can affect the functional life of these structural components leading to catastrophic failures in mission critical applications resulting in loss of lives and structural component. Therefore, it is very important to understand the influence of the dissolved hydrogen on the failure of these structural materials due to cyclic loading (fatigue). For the next generation of hydrogen based fuel cell vehicles and energy systems, it is very crucial to develop structural materials for hydrogen storage and containment which are highly resistant to hydrogen embrittlement. These materials should also be able to provide good long term life in cyclic loading, without undergoing degradation, even when exposed to hydrogen rich environments for extended periods of time. The primary focus of this investigation was to examine the influence of dissolved hydrogen on the fatigue crack growth behaviour of a commercially available high strength medium carbon low alloy (AISI 4140) steel. The secondary objective was to examine the influence of microstructure on the fatigue crack growth behaviour of this material and to determine the

  4. Cladding of aluminum on AISI 304L stainless steel by cold roll bonding: Mechanism, microstructure, and mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Akramifard, H.R., E-mail: akrami.1367@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Mirzadeh, H., E-mail: hmirzadeh@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Parsa, M.H., E-mail: mhparsa@ut.ac.ir [School of Metallurgy and Materials Engineering, College of Engineering, University of Tehran, P.O. Box 11155-4563, Tehran (Iran, Islamic Republic of); Center of Excellence for High Performance Materials, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of); Advanced Metalforming and Thermomechanical Processing Laboratory, School of Metallurgy and Materials Engineering, University of Tehran, Tehran (Iran, Islamic Republic of)

    2014-09-08

    The AA1050 aluminum alloy and AISI 304L stainless steel sheets were stacked together to fabricate Al/304L/Al clad sheet composites by the cold roll bonding process, which was performed at temperatures of ∼100 and 23 °C to produce austenitic and austenitic–martensitic microstructures in the AISI 304L counterpart, respectively. The peel test results showed that the threshold reduction required to make a suitable bond at room temperature is below 10%, which is significantly lower than the required reduction for cold roll bonding of Al sheets. The tearing of the Al sheet during the peel test signified that the bond strength of the roll bonded sheets by only 38% reduction has reached the strength of Al, which is a key advantage of the developed sheets. The extrusion of Al through the surface cracks and settling inside the 304L surface valleys due to strong affinity between Al and Fe was found to be the bonding mechanism. Subsequently, the interface and tensile behaviors of three-layered clad sheets after soaking at 200–600 °C for 1 h were investigated to characterize the effect of annealing treatment on the formation and thickening of intermetallic compound layer and the resultant mechanical properties. Field emission scanning electron microscopy, X-ray diffraction, and optical microscopy techniques revealed that an intermediate layer composed mainly of Al{sub 13}Fe{sub 4}, FeC and Al{sub 8}SiC{sub 7} forms during annealing at 500–600 °C. A significant drop in tensile stress–strain curves after the maximum point (UTS) was correlated to the interface debonding. It was found that the formation of intermediate layer by post heat treatment deteriorates the bond quality and encourages the debonding process. Moreover, the existence of strain-induced martensite in clad sheets was found to play a key role in the enhancement of tensile strength.

  5. Joining of Dissimilar alloy Sheets (Al 6063&AISI 304 during Resistance Spot Welding Process: A Feasibility Study for Automotive industry

    Directory of Open Access Journals (Sweden)

    Reddy Sreenivasulu

    2014-12-01

    Full Text Available Present design trends in automotive manufacture have shifted emphasis to alternative lightweight materials in order to achieve higher fuel efficiency and to bring down vehicle emission. Although some other joining techniques are more and more being used, spot welding still remains the primary joining method in automobile manufacturing so far. Spot welds for automotive applications should have a sufficiently large diameter, so that nugget pullout mode is the dominant failure mode. Interfacial mode is unacceptable due to its low load carrying and energy absorption capability. Strength tests with different static loading were performed in, to reveal the failure mechanisms for the lap-shear geometry and the cross-tension geometry. Based on the literature survey performed, venture into this work was amply motivated by the fact that a little research work has been conducted to joining of dissimilar materials like non ferrous to ferrous. Most of the research works concentrated on joining of different materials like steel to steel or aluminium alloy to aluminium alloy by resistance spot welding. In this work, an experimental study on the resistance spot weldability of aluminium alloy (Al 6063 and austenitic stainless steel (AISI304 sheets, which are lap joined by using a pedestal type resistance spot welding machine. Welding was conducted using a 45-deg truncated cone copper electrode with 10-mm face diameter. The weld nugget diameter, force estimation under lap shear test and T – peel test were investigated using digital type tensometer attached with capacitive displacement transducer (Mikrotech, Bangalore, Model: METM2000ER1. The results shows that joining of Al 6063 and AISI 304 thin sheets by RSW method are feasible for automotive structural joints where the loads are below 1000N act on them, it is observed that by increasing the spots per unit length, then the joint with standing strength to oppose failure is also increased linearly incase of

  6. The significance of passivation treatments on AISI 314 foam pieces to be used as substrates for catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Bortolozzi, J.P.; Banus, E.D.; Milt, V.G.; Gutierrez, L.B. [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina); Ulla, M.A., E-mail: mulla@fiq.unl.edu.ar [Instituto de Investigaciones en Catalisis y Petroquimica, INCAPE (FIQ, UNL-CONICET), Santiago del Estero 2829, 3000 Santa Fe (Argentina)

    2010-11-01

    Several properties of metallic foams such as their low density, high mechanical strength and good coefficients of heat and mass transfer make them attractive for applications in catalysis. Important modifications in the composition and morphology of the metallic foam surfaces can take place when they are submitted to treatments at high temperatures. These surface changes are due to the migration of some elements from the metallic core to the pore surface, thus inducing a passivation via an oxide layer formation. This new layer avoids further metallic segregation and generates a surface roughness, both effects having a significant impact on the catalytic coating quality. This work analyzes the effects of calcination temperature and time on the chemistry and morphology of the metallic surface corresponding to the AISI 314 stainless steel foams of 50 and 60 ppi. The chemical and morphological surface changes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX) analysis and Laser Raman Spectroscopy (LRS). The application of high temperature treatments on AISI 314 foams promotes the formation of a surface layer containing chromium oxide and spinel-type compounds of chromium, iron and manganese. The optimum treatment temperature for this type of structures seems to be 900 deg. C because both the adhesion and thickness of the layer formed are adequate. For the sample with smaller pores (60 ppi) the optimal treatment time is close to 2 h and for that with larger pores (50 ppi) the recommended time is 20 h. Under these conditions, a compromise is found between adhesion, thickness and surface roughness, suitable for the subsequent deposition of catalytic material.

  7. Comportamiento a la corrosión del acero 316L sinterizado con distinto grado de porosidad

    Directory of Open Access Journals (Sweden)

    Soria, L.

    1998-05-01

    Full Text Available AISI 316L sintered samples, with porosities ranging from 9 to 40 %, and without alloying losses at the surface, have been prepared. Those samples, along with conventional (rolled steel samples, have been subjected to electrochemical and immersion corrosion tests. According to porosity size quantitative measurements, before and after corrosion tests, two corrosion mechanisms, general and pitting, are proposed depending on the initial porosity.

    A partir de polvos de acero inoxidable AISI 316L, se han preparado muestras con distinto grado de porosidad, entre el 9 y el 40 %, asegurando que la superficie externa no resulta alterada durante el procesado pulvimetalúrgico. Junto a muestras de chapa laminada de la misma composición, han sido sometidas a ensayos de inmersión y a ensayos electroquímicos de corrosión. Estudios cuantitativos de la evolución de la porosidad superficial, antes y después de los ensayos, permiten plantear diversas hipótesis acerca de los mecanismos de corrosión actuantes en función de la porosidad de las piezas.

  8. Estudio experimental de la conducción del calor en el maquinado de materiales endurecidos con altas velocidades de corte. // Experimental study of heat conduction in mechanization with high cutting speeds of hardened materials.

    Directory of Open Access Journals (Sweden)

    L. Cardoso Brandão

    2006-01-01

    Full Text Available El trabajo trata del estudio teórico-experimental de la conducción del calor en los materiales endurecidos, usados para laproducción de moldes y matrices, al maquinarlos con altas-velocidades del corte. Los materiales utilizados son los acerosAISI P20 y AISI D2. Los ensayos se realizaron con fresas de punta esférica (Ball Nose con revestimiento (TiAlN y lasprobetas para los ensayos tienen la forma de una ¼ parte de un tubo de 28 mm de diámetro con una longitud de 100 mm.Las pruebas realizadas demuestran la variación de la temperatura en función de los diferentes sistemas de refrigeración. Seutilizo aire comprimido y aire comprimido frío, comparándose las temperaturas de las probetas con el sistema sinrefrigeración de ningún tipo. Fueron también evaluadas las deformaciones sufridas por la superficie maquinada, debido alas variaciones de temperatura teniendo en cuenta la influencia de los sistemas de refrigeración empleados.Palabras claves: Temperatura; conducción del calor; alta velocidad de corte, moldes y matrices._________________________________________________________________________Abstract.This paper deals with the theoretical-experimental study of heat conduction in hardened materials for the production ofmolds and dies using high speed cutting. The employed materials were the AISI P20 and AISI D2 steels, being the testscarried out with (TiAlN coated ball nose in a work piece with the shape of a 1/4 tube with 28 mm diameter and 100 mmlength. This investigation demonstrates the variation of temperature as a function of different cooling systems, that is,compressed air and compressed cold air. Possible geometric deformation of the machined surfaces due to these variationsin temperature for distinct cooling systems was also evaluated.Keywords: Temperature, heat exchange; high cutting speed, dies.

  9. Caracterización mediante la técnica EBSD de la deformación de chapa de acero inoxidable AISI 304 DDQ bajo tensiones multiaxiales típicas de la embutición

    Directory of Open Access Journals (Sweden)

    Coello, J.

    2009-10-01

    Full Text Available The main aim of this work is to evaluate AISI 304 DDQ stainless steel behaviour under deep drawing deformation condition, that is, pure shear deformation in which material suffers a typical deformation under tension-biaxial compression stresses system. The microestructural evolution has been investigated by optical microscopy and by EBSD technique. The success of the EBSD analysis has been established for the deformation conditions experimented here. It has been determined the rolling direction and the equivalent strain influence on the crystallographic orientation maps, misorientation diagrams and poles figures. The results let the authors say the low angle misorientations corresponding to 0, 45 and 90° rolling directions have an inverse correlation with the material anisotropy. Initial prestraining has been considered also and the analysis of this aspects lead to establish that the increment of the intragranular misorientations with the strain depends on the initial state of the steel; this increment is observed to be minor for samples with initial prestraining. High angle misorientation analysis (>15° indicates that the grain boundaries character distributions depends on the deformation.

    El objetivo de este trabajo es evaluar el comportamiento del acero inoxidable AISI 304 DDQ durante un proceso de deformación típico del conformado de chapa por embutición, tracción-compresión biaxial (T-CC, determinando la evolución microestructural mediante microscopía óptica y EBSD. Se ha establecido la validez del análisis efectuado por EBSD para las condiciones de deformación consideradas en este trabajo. Se ha analizado la influencia de la dirección de laminación y de la deformación equivalente sobre los mapas de orientación cristalina, diagramas de desorientación y figuras de polos inversa, determinando que las desorientaciones de ángulo bajo obtenidas en muestras deformadas a 0°, 45°, y 90° respecto a la dirección de

  10. Investigando con personas con dificultades de aprendizaje

    Directory of Open Access Journals (Sweden)

    Borja González Luna

    2013-12-01

    Full Text Available El artículo muestra los orígenes de lo que Walmsley (2008 denomina «investigación inclusiva». Para comprender qué se entiende por investigación inclusiva tenemos que remontarnos a los debates epistemológicos sobre las metodologías cuantitativas y cualitativas, acontecidos en la década de los 90, en torno a la revista Disability & Society. A partir de una síntesis de dichos debates, focalizados en el ámbito de la «discapacidad intelectual y del desarrollo», se exponen dos estrategias de colaboración con dicha población: a una aproximación etnográfica (de trabajo grupal, y b una aproximación biográfica (de trabajo individual. A continuación se esboza un posible diseño de trabajo de campo que intenta superar el paradigma cualitativo «clásico» con el objetivo de incluir a dicho colectivo más allá del rol de «sujetos de la investigación». Para finalizar se recoge el debate sobre la accesibilidad de los resultados de la investigación a los participantes en dichas investigaciones, y con ello la necesaria innovación en el ámbito de las «devoluciones» de los resultados, cuando se trata de incluir a personas que presentan limitaciones para la comprensión del lenguaje abstracto oral y/o escrito.

  11. Wear properties of Fe-Cr-C and B{sub 4}C powder coating on AISI 316 stainless steel analyzed by the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Gur, Ali Kaya; Ozay, Cetin; Orhan, Ayhan; Buytoz, Soner; Caligulu, Ugur; Yigitturk, Necmettin [Firat Univ., Elazig (Turkey). Faculty of Technical Education

    2014-06-01

    In this study, the plasma arc welded cladding of FeCrC and B{sub 4}C powder mixtures alloyed with 70 wt.-% Cr on the surface of AISI 316 stainless steel was investigated. Application of the Taguchi method revealed respective effects on the abrasive wear resistance of the cladding layer on the stainless steel. The abrasive wear behaviour of the AISI 316 stainless steel surfaces coated with Fe-Cr-C and with 10 wt.-%, 15 wt.-%, 20 wt.-%, and 25 wt.-% B{sub 4}C was investigated by using four loads and four distances for the 220 mesh SiC abrasive. Results were analyzed by variance analysis using ANOVA, and effects of parameters on the wear rate were determined as percentage rate. Furthermore, the error ratio was statistically evaluated. The experimental results were analyzed by the respective analysis of means and variance which is discussed in detail. (orig.)

  12. Processing of AISI M2 HSS with addition of NbC by mechanical alloying using two different types of attritor mills

    Energy Technology Data Exchange (ETDEWEB)

    Araujo Filho, Oscar Olimpio de; Gonzalez, Cezar Henrique; Urtiga Filho, Severino Leopoldino, E-mail: oscaroaf98@hotmail.com, E-mail: gonzalez@ufpe.br, E-mail: urtiga@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Engenharia Mecanica; Neves, Mauricio David Martins das, E-mail: mdneves@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Ambrozio Filho, Francisco, E-mail: ambrozio@fei.edu.br [Centro Universitario da FEI, Sao Bernardo do Campo, SP (Brazil)

    2009-07-01

    The processing of a molybdenum AISI M2 high speed steel with the addition of NbC (6% in mass) by a Powder Metallurgy technique of Mechanical Alloying is the aim of this work. Mechanical Alloying (MA) has been used primarily for particle size reduction, to its present status as an important method for the preparation of either materials with enhanced physical and mechanical properties or, indeed, new phases, or new engineering materials. In this work, niobium carbide (NbC) was added to the AISI M2 HSS powders by Mechanical Alloying technique in two different types of attritor mills and the materials which resulted were characterized by means of SEM plus EDS. The powders were processed in a horizontal attritor Zoz mill and in a vertical attritor mill developed in our laboratory. The parameters of milling were distinct and the results of the processing were compared. (author)

  13. INVESTIGATION SURFACE ROUGHNESS AND CHARACTERIZATION OF CUTTING FRONT SIDE GEOMETRY IN THE CUTTING OF AISI 1030 MATERIAL WITH ABRASIVE WATER JET

    Directory of Open Access Journals (Sweden)

    Adnan AKKURT

    2009-01-01

    Full Text Available Abrasive water jet (AWJ is used as a new and alternative cutting technique in industry to form the materials that are hard to cut. In this study, AISI 1030 steel samples in different thickness were cut with AWJ process. The samples were cut with different cutting speeds. The effect of cutting speed on the surface characteristics was investigated. The results of the study show that AWJ can be used as an effective cutting process to form sharp corners and edges.

  14. Microestrutura de uma Solda Dissimilar entre o Aço Inoxidável Ferrítico AISI 410S e o Aço Inoxidável Austenítico AISI 304L Soldado pelo Processo FSW

    Directory of Open Access Journals (Sweden)

    Tathiane Caminha Andrade

    2015-12-01

    Full Text Available Resumo O presente trabalho visa investigar a microestrutura formada na soldagem dissimilar entre chapas de aços inoxidáveis ferríticos AISI 410S e aços inoxidáveis austeníticos AISI 304L pelo processo friction stir welding. A soldagem foi realizada com o ajuste dos seguintes parâmetros: rotação 450 rpm; velocidade de soldagem de 1,0 mm/s; e força axial 40 kN. O aço AISI 410S foi posicionado no lado de avanço enquanto que o aço AISI 304L foi posicionado no lado de retrocesso. A análise consistiu de preparação metalográfica e caracterização microestrutural por microscopia ótica e microscopia eletrônica de varredura. Para o aço AISI 410S foi observada a formação de martensita associada com ferrita na zona de mistura (ZM, zona termomecanicamente afetada (ZTMA e na zona afetada pelo calor (ZAC. As características do processo de soldagem FSW resultaram num refino de grão para o aço inoxidável ferrítico, posicionado no lado de avanço, tanto na ZM quanto nas ZTMA e ZAC. O mesmo comportamento não foi observado para o lado austenítico.

  15. Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lin Yimin [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China) and Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China)]. E-mail: linyimin_2001@yahoo.com.cn; Lu Jian [LASMIS, University of Technology of Troyes, 10000 Troyes (France); Wang Liping [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100039 (China); Xu Tao [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China); Xue Qunji [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, 18 Middle Tianshui Road, Lanzhou 730000 (China)]. E-mail: qjxue@ns.lzb.ac.cn

    2006-12-15

    A plastic deformation surface layer with nanocrystalline grains was produced on AISI 321 austenitic stainless steel by means of surface mechanical attrition treatment (SMAT). Low-temperature nitriding of SMAT and un-SMAT AISI 321 stainless steel was carried out in pulsed-DC glow discharge. The effect of SMAT pretreatment on the microstructure and properties of the stainless steel were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Vickers hardness tester and UMT-2MT tribometer. The results show that the plasma nitriding of AISI 321 steel can be enhanced considerably by means of SMAT process before nitriding, and a much thicker nitrogen diffusion layer with higher hardness was obtained for the SMAT samples when compared with un-SMAT samples. In addition, the wear resistance and load capacity of the nitrided layers on the SMAT samples was much higher than that of the un-SMAT samples due to the thicker S phase case and the gradient nitrogen diffusion layer.

  16. In vitro response of human peripheral blood mononuclear cells to AISI 316L austenitic stainless steel subjected to nitriding and collagen coating treatments.

    Science.gov (United States)

    Stio, Maria; Martinesi, Maria; Treves, Cristina; Borgioli, Francesca

    2015-02-01

    Surface modification treatments can be used to improve the biocompatibility of austenitic stainless steels. In the present research two different modifications of AISI 316L stainless steel were considered, low temperature nitriding and collagen-I coating, applied as single treatment or in conjunction. Low temperature nitriding produced modified surface layers consisting mainly of S phase, which enhanced corrosion resistance in PBS solution. Biocompatibility was assessed using human peripheral blood mononuclear cells (PBMC) in culture. Proliferation, lactate dehydrogenase (LDH) levels, release of cytokines (TNF-α, IL-1β, IL-12, IL-10), secretion of metalloproteinase (MMP)-9 and its inhibitor TIMP-1, and the gelatinolytic activity of MMP-9 were determined. While the 48-h incubation of PBMC with all the sample types did not negatively influence cell proliferation, LDH and MMP-9 levels, suggesting therefore a good biocompatibility, the release of the pro-inflammatory cytokines was always remarkable when compared to that of control cells. However, in the presence of the nitrided and collagen coated samples, the release of the pro-inflammatory cytokine IL-1β decreased, while that of the anti-inflammatory cytokine IL-10 increased, in comparison with the untreated AISI 316L samples. Our results suggest that some biological parameters were ameliorated by these surface treatments of AISI 316L.

  17. Soledad con espectador

    OpenAIRE

    2011-01-01

    Este proyecto se plantea como una investigación de las posibilidades del dibujo como una herramienta para relatar una historia propia que se empapa de realidad y de ficción con el deseo de confundir al espectador y suscitarle preguntas. Para ello me he servido de mi propia imagen como personaje central. Éste se presenta duplicado, multiplicado, repetido e interactúa consigo mismo en un espacio imaginario con intención de simular aquello que se revela en el interior de la psique. Mi trabajo se...

  18. Giochiamo con i robot

    Directory of Open Access Journals (Sweden)

    Andrea Bonarini

    2009-01-01

    Full Text Available "Giochiamo con i robot" e' un laboratorio interattivo per grandi e piccini realizzato per l'edizione 2007 del Festival della Scienza di Genova. Lungo un percorso che va dalla telerobotica alla robotica evolutiva, il laboratorio sviluppa il tema di dare intelligenza ai robot. Questo percorso, le cui tappe sono le varie installazioni, si conclude nella "bottega" dove e' possibile costruire e programmare i propri robot o smontare e modificare quelli esposti durante il percorso didattico. I visitatori sono coinvolti in attivita' ludiche grazie alle quali possonoentrare in contatto con alcune delle idee potenti della robotica,

  19. en pacientes con obesidad

    Directory of Open Access Journals (Sweden)

    Alcia María Alvarado Sánchez

    2005-01-01

    Full Text Available El objetivo de este estudio fue evaluar la eficacia de una intervención psicológica en pacientes con obesidad. Se utilizó un diseño cuasiexperimental con un grupo de estudio y un grupo control. Después de la intervención, se encontró una diferencia significativa en la reducción de peso entre los grupos. Asimismo, hubo un incremento significativo en la autoestima del grupo estudiado.

  20. Funcionando con la computadora

    OpenAIRE

    Álvarez, Eduardo; Astiz, Mercedes; Medina, Perla; Montero, Y.; Oliver, María; Rocerau, M. Cristina; VALDEZ, Guillermo; Vecino, María; Vilanova, Silvia

    2004-01-01

    En este trabajo se presenta la descripción y resultados de la segunda etapa de una experiencia planteada con el objetivo de indagar la manera en que los alumnos determinan e interpretan funciones que explican situaciones problemáticas valiéndose de una nueva forma de trabajo en el aula: la utilización de la computadora como herramienta y un programa asistente matemático. La primera etapa consistió en el desarrollo de un taller optativo con alumnos de entre 14 y 15 años de edad del Colegio Dr....

  1. Effect of Homogenization &Quenching Media on the Mechanical Properties of Sintered Hot Forged AISI 9250 P/MSteel Preforms

    Directory of Open Access Journals (Sweden)

    S. Aamani

    2014-10-01

    Full Text Available Present investigation is an attempt to generate experimental data in order to establish the influence of homogenization and cooling media on the mechanical properties of hot forged AISI 9250 sintered P/M steel to square cross-section bars produced using elemental powders. The elemental powders corresponding to final AISI 9250 composition ofFe-0.5%C-0.75%Mn-2.0%Si were taken in an appropriate proportion and blended in a pot mill for a period of 32 hours while maintaining the powder to ball ratio by weight as 1.1:1. Compacts of 28mm diameter and 36mm height were prepared on a 1.0 MN capacity Universal Testing Machine (UTM and using suitable die, punch and bottom insert assembly in the density range of 85±1 percent of theoretical by applying the pressure in the range of 550±10 MPa and by taking pre-weighed powder blend. In all 36 compacts were prepared. These green compacts were coated using the indigenously developed ceramic coating and the same was allowed to dry under the ambient conditions for a period of 14-16 hours. These ceramic coated compacts were re-coated 90° to the previous coating and re-dried under the aforementioned conditions for the same length of time. Ceramic coated compacts were sintered in an electric muffle furnace at 1120±10°C for a period of 120 minutes and subsequently hot forged to square cross-section bars of approximate dimensions of 14mm X 14mm X 95-100mm on a friction screw press of 1.00MN capacity at the sintering temperature itself. Nine forged specimens were oil quenched and remaining 27 forged bars were homogenized at the sintering temperature for a period of 60 minutes followed by quenching nine of them in oil, nine specimens in air and remaining nine were cooled in the furnace itself. Standard tensile specimens were prepared from each set and tested for evaluation of mechanical properties followed by SEM Fractography on the fractured specimen surfaces. Tensile tests results have established that the

  2. Machining tools in AISI M2 high-speed steel obtained by spray forming process; Ferramentas de usinagem em aco rapido AISI M2 obtido por conformacao por 'spray'

    Energy Technology Data Exchange (ETDEWEB)

    Jesus, Edilson Rosa Barbosa de. E-mail: erbjesus@usp.br

    2004-07-01

    The aim of the present work was the obtention of AISI M2 high-speed steel by spray forming technique and the material evaluation when used as machining tool. The obtained material was hot rolled at 50% and 72% reduction ratios, and from which it was manufactured inserts for machining tests. The performance of inserts made of the spray formed material was compared to inserts obtained from conventional and powder metallurgy (MP) processed materials. The spray formed material was chemical, physical, mechanical and microstructural characterised. For further characterisation, the materials were submitted to machining tests for performance evaluation under real work condition. The results of material characterisation highlight the potential of the spray forming technique, in the obtention of materials with good characteristics and properties. Under the current processing, hot rolling and heat treatments condition, the analysis of the results of the machining tests revealed a very similar behaviour among the tested materials. Proceeding a criterious analysis of the machining results tests, it was verified that the performance presented by the powder metallurgy material (MP) was slight superior, followed by conventional obtained material (MConv), which presented a insignificant advantage over the spray formed and hot rolled (72% reduction ratio) material. The worst result was encountered for the spray forming and hot rolled (50% reduction ratio) material that presented the highest wear values. (author)

  3. Study of the S phase structure on the AISI 316L steel by X-ray diffraction and Moessbauer spectroscopy; Estudo da estrutura da fase S no aco AISI 316L por difracao de raios X e espectroscopia Moessbauer

    Energy Technology Data Exchange (ETDEWEB)

    Gontijo, L.C. [Centro Federal de Educacao Tecnologica do Espirito Santo, Vitoria, ES (Brazil). Coordenadoria de Ciencia e Tecnologia; Machado, R.; Nascente, P.A.P. [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Engenharia de Materiais]. E-mail: nascente@power.ufscar.br; Miola, E.J. [Universidade Federal de Sao Carlos, SP (Brazil). Dept. de Fisica; Casteletti, L.C. [Universidade de Sao Paulo, Sao Carlos, SP (Brazil). Dept. de Engenharia de Materiais, Aeronautica e Automobilistica

    2005-07-01

    The plasma-nitriding technology has been employed in the industry with the objective of improving the surface properties of metals and alloys. By using the conventional nitriding process at low temperature, some of the properties of the austenitic stainless steels are enhanced by the formation of the S phase, also called expanded austenite. This phase is formed on the surfaces of the austenitic stainless steels nitrided under certain conditions. In the past years, an extensive research has been carried out for the understanding of the S phase, but some questions remain with no answer or with contradictory explanations. In this work, the AISI 316L steel was plasma-nitrided at 350 and 400 deg C, and the samples were characterized by X-ray diffraction (XRD) and conversion electron Moessbauer spectroscopy (CEMS) in order to investigate the S phase. XRD analysis identified the presence of a distorted cubic structure phase. The layer consists of a distribution of nitrogen austenite with different content of nitrogen, ranging from approximately 10 to 40 at-%, and also {gamma}-Fe{sub 4}N and {epsilon}-Fe{sub 2-3}N phases. Moessbauer spectroscopy corroborates these results, and shows a decrease in nitrogen austenite with the increase in nitriding temperature. This decrease is related to the transformation of the nitrogen austenite to the {gamma}-Fe{sub 4}N phase. (author)

  4. Influence of the density of the microwave plasma in the nitridation of the AISI 4140 steel; Influencia de la densidad del plasma de microondas en la nitruracion de acero AISI 4140

    Energy Technology Data Exchange (ETDEWEB)

    Chirino O, S.; Camps C, E.; Escobar A, L.; Mejia H, J.A. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2004-07-01

    A source of microwaves plasma type ECR was used to modify those mechanical properties of the surface of steel pieces AISI 4140. The experiments were carried out in a range of pressure among 4 X 10{sup -4} and 7 X 10{sup -4} Torr using one mixture of gases 60/40 hydrogen / nitrogen and an incident power of the microwaves of 400 W. Previous to the treatment of the samples, the plasma was studied using one Langmuir probe to determine the temperature of the electrons and the density of the plasma, the species excited in the plasma were determined by means of Optical emission spectroscopy. All the samples were treated during 50 min in a regime of low temperature (- 250 C), and the surface hardness it was increased up of 100% of their initial value, with a depth of penetration of the nitrogen of 4.5 {mu} m. The biggest hardness and depth of penetration of the nitrogen were obtained when the biggest density in the plasma was used to carry out the experiments. (Author)

  5. Crack propagation in stainless steel AISI 304L in Hydrogen Chemistry conditions (HWC); Propagacion de Grietas en Acero Inoxidable AISI 304L en Condiciones de Quimica de Hidrogeno (HWC)

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Fuentes C, P.; Merino C, F. [ININ, Carretera Mexico -Toluca s/n, La Marquesa, Ocoyoacac, Mexico (Mexico); Castano M, V. [Instituto de Fisica Aplicada, UNAM, Km 15.5 Carretera Queretaro-San Luis Potosi, Juriquilla, Queretaro (Mexico)]. e-mail: ads@nuclear.inin.mx

    2006-07-01

    Velocities of crack growth in samples type CT pre cracking of stainless steel AISI 304l solder and sensitized thermally its were obtained by the Rising Displacement method or of growing displacement. It was used a recirculation circuit that simulates the operation conditions of a BWR type reactor (temperature of 280 C and a pressure of 8 MPa) with the chemistry modified by the addition of hydrogen with and without the addition of impurities of a powerful oxidizer like the Cu{sup +} ion. In each essay stayed a displacement velocity was constant of 1x10{sup -9} m/s, making a continuous pursuit of the advance of the crack by the electric potential drop technique. Contrary to the idea of mitigation of the crack propagation velocity by effect of the addition of the hydrogen in the system, the values of the growth velocities obtained by this methodology went similar to the opposing ones under normal operation conditions. To the finish of the rehearsal one carries out the fractographic analysis of the propagation surfaces, which showed cracks growth in trans and intergranular way, evidencing the complexity of the regulator mechanisms of the IGSCC like in mitigation conditions as the alternative Hydrogen Chemistry. (Author)

  6. Propagation of crevices in stainless steel AISI304L in conditions of hydrogen chemistry (HWC); Propagacion de grietas en acero inoxidable AISI304L en condiciones de quimica de hidrogeno (HWC)

    Energy Technology Data Exchange (ETDEWEB)

    Diaz S, A.; Fuentes C, P.; Merino C, F. [ININ, 52750 Ocoyoacac, Estado de Mexico (Mexico); Castano M, V. [IFA-UNAM, Juriquilla, Queretaro (Mexico)]. e-mail: ads@nuclear.inin.mx

    2006-07-01

    Crevice growth velocities in samples of AISI 304L stainless steel thermally welded and sensitized were obtained by the Rising displacement method or of growing displacement. It was used a recirculation circuit in where the operation conditions of a BWR type reactor were simulated (temperature of 288 C and a pressure of 8 MPa) with the chemistry modified by the addition of hydrogen with and without the addition of impurities of a powerful oxidizer like the Cu{sup ++} ion. CT pre cracked specimens were used and each rehearsal stayed to one constant displacement velocity of 1 x 10{sup -9} m/s (3.6 {mu}m/hr), making a continuous pursuit of the advance of the crack by the electric potential drop technique. To the end of the rehearsal it was carried out the fractographic analysis of the propagation surfaces. The values of the growth velocities obtained by this methodology went similar to the opposing ones under normal conditions of operation; while the fractographic analysis show the cracks propagation in trans and intergranular ways, evidencing the complexity of the regulator mechanisms of the one IGSCC even under controlled ambient conditions or with mitigation methodologies like the alternative hydrogen chemistry. (Author)

  7. Characterization of welding of AISI 304l stainless steel similar to the core encircling of a BWR reactor; Caracterizacion de soldaduras de acero inoxidable AISI 304L similares a las de la envolvente del nucleo de un reactor BWR

    Energy Technology Data Exchange (ETDEWEB)

    Gachuz M, M.E.; Palacios P, F.; Robles P, E.F. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)

    2003-07-01

    Plates of austenitic stainless steel AISI 304l of 0.0381 m thickness were welded by means of the SMAW process according to that recommended in the Section 9 of the ASME Code, so that it was reproduced the welding process used to assemble the encircling of the core of a BWR/5 reactor similar to that of the Laguna Verde Nucleo electric plant, there being generated the necessary documentation for the qualification of the one welding procedure and of the welder. They were characterized so much the one base metal, as the welding cord by means of metallographic techniques, scanning electron microscopy, X-ray diffraction, mechanical essays and fracture mechanics. From the obtained results it highlights the presence of an area affected by the heat of up to 1.5 mm of wide and a value of fracture tenacity (J{sub IC}) to ambient temperature for the base metal of 528 KJ/m{sup 2}, which is diminished by the presence of the welding and by the increment in the temperature of the one essay. Also it was carried out an fractographic analysis of the fracture zone generated by the tenacity essays, what evidence a ductile fracture. The experimental values of resistance and tenacity are important for the study of the structural integrity of the encircling one of the core. (Author)

  8. fertilizada con diferentes abonos

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Elizondo-Salazar

    2007-01-01

    Full Text Available Producción y calidad de la biomasa de morera (Morus alba fertilizada con diferentes abonos. Se llevó a cabo un experimento en la Estación Experimental “Alfredo Volio Mata” de la Universidad de Costa Rica con el fi n de evaluar la aplicación de 150 kg de N/ha/año proveniente de dos abonos orgánicos: lombriabono y compostaje; y de un fertilizante químico, sobre la producción y calidad de la biomasa de morera. El periodo experimental comprendió un ciclo de 12 meses, iniciando en julio del 2003 y fi nalizando en julio del 2004. Se utilizó una plantación de morera de 12 años de establecida con una densidad de siembra de 27.777 plantas/ ha. Se empleó un diseño de bloques completos al azar con cuatro tratamientos: dos abonos orgánicos, nitrato de amonio (33,5% N y un control. Las plantas se podaron a 0,6 m sobre el nivel del suelo al inicio del ensayo. Durante el periodo experimental, las plantas fueron podadas consecutivamente cada 90 días. Las hojas y los tallos fueron separados y analizados para determinar el contenido de materia seca y proteína cruda. La producción de materia seca fue 23% superior y el contenido de proteína cruda fue signifi cativamente mayor con el nitrógeno químico, mientras que el contenido de materia seca fue menor. No se encontraron diferencias signifi cativas entre el tratamiento control y los tratamientos orgánicos.

  9. Exploration of surface hydrophilic properties on AISI 304 stainless steel and silicon wafer against aging after atmospheric pressure plasma treatment

    Science.gov (United States)

    Chuang, Shang-I.; Duh, Jenq-Gong

    2014-11-01

    The aim of this work is to seek the enhanced surface hydrophilic properties on AISI 304 stainless steel and silicon wafer after atmospheric pressure plasma treatment using a specifically designed atmospheric pressure plasma jet. The aging tendency of surface hydrophilic property under air is highlighted. It is concluded that both of the silicon wafer and stainless steel treated with plasma generated from supply gas of argon 15 slm mixed with oxygen 40 sccm shows a better tendency on remaining high water contact angle as compared to that with pure argon and nitrogen addition. Additional peaks of O I (777, 844 nm), O II (408 nm) are detected by optical emission spectroscope indicating the presence of the oxygen radicals and ionic species, which interact with surfaces and thus contribute to low water contact angle (WCA) surfaces. Moreover, the result acquired from X-ray photoelectron spectroscopy (XPS) indicates that the increase in the oxygen-related bonding exhibits a better contribution on remaining high surface energy over a period of time.

  10. Finite Element Analysis of Cross Rolling on AISI 304 Stainless Steel: Prediction of Stress and Strain Fields

    Science.gov (United States)

    Rout, Matruprasad; Pal, Surjya Kanta; Singh, Shiv Brat

    2017-02-01

    Studies on the effect of strain path during rolling has been carried out for a long time, but the same has not been done using Finite Element Analysis (FEA). Change in strain path affects the state variables in the rolled plate like stress, strain, temperature etc. In the current work, Finite Element Analysis for cross rolling of AISI 304 austenitic stainless steel has been carried out by rotating the plate by 90° in between the passes. To analyze stress and strain fields in the material for cross rolling, a full 3D model of work-roll and plate has been developed using rigid-viscoplastic finite element method. The stress and strain fields, considering von-Mises yield criteria, are calculated by using updated Lagrangian method. In addition to these, the model also calculates the normal pressure and strain rate distribution in the plate during cross rolling. The nature of the variations of stress and strain fields in the plate, predicted by the model, is in good agreement with the previously published works for unidirectional rolling.

  11. Transitions in Wear and Friction of Carbon Fiber Reinforced Copper Matrix Composite Sliding Against AISI-1045 Steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The friction and wear properties of carbon fiber reinforced copper matrix composite in dry sliding against AISI-1045 steel was evaluated by a block-on-ring test machine. It was shown that the low frictional factor and wear rate of the composite block could be maintained when pressure or velocity was below a certain value. But when the pressure or velocity exceeded the critical value, the friction factor and wear rate tended to increase rapidly with pressure and sliding velocity. The morphologies, elemental compositions, and surface profile of worn composite surfaces at different wear stages were analyzed by means of scanning electron microscopy, energy dispersive spectrometry, and profile-meter. It was found that low values of friction and wear were due to a thin solid film forming on the surface of the composite block which includes carbon and copper at a mild wear stage. The film could impede adhesion and provide some degree of self-lubrication. When the film included more metal elements and were damaged, severe wear happened, and the wear rate increased sharply. As a result, a transition diagram in friction and wear was constructed, which provided pressure and velocity conditions of change from mild wear and low friction to severe wear and high friction for the wear-resisting design.

  12. Parametric Optimization Of Gas Metal Arc Welding Process By Using Grey Based Taguchi Method On Aisi 409 Ferritic Stainless Steel

    Science.gov (United States)

    Ghosh, Nabendu; Kumar, Pradip; Nandi, Goutam

    2016-10-01

    Welding input process parameters play a very significant role in determining the quality of the welded joint. Only by properly controlling every element of the process can product quality be controlled. For better quality of MIG welding of Ferritic stainless steel AISI 409, precise control of process parameters, parametric optimization of the process parameters, prediction and control of the desired responses (quality indices) etc., continued and elaborate experiments, analysis and modeling are needed. A data of knowledge - base may thus be generated which may be utilized by the practicing engineers and technicians to produce good quality weld more precisely, reliably and predictively. In the present work, X-ray radiographic test has been conducted in order to detect surface and sub-surface defects of weld specimens made of Ferritic stainless steel. The quality of the weld has been evaluated in terms of yield strength, ultimate tensile strength and percentage of elongation of the welded specimens. The observed data have been interpreted, discussed and analyzed by considering ultimate tensile strength ,yield strength and percentage elongation combined with use of Grey-Taguchi methodology.

  13. In-Process Prediction of Tool Wear and Workpiece Surface Temperature in Turning of AISI D2 Steel

    Directory of Open Access Journals (Sweden)

    Sudhansu Ranjanjan Das

    2012-08-01

    Full Text Available Present days increasing the productivity and the quality of the machined parts are the main challenges of metal cutting industry during turning processes. Optimization methods in turning processes, considered being a vital role for continual improvement of output quality in product and processes include modeling of input-output and in process parameters relationship and determination of optimal cutting conditions. This paper presents an optimization method of the cutting parameters (cutting speed, depth of cut and feed in dry turning of AISI D2 steel to achieve minimum tool wear and low workpiece surface temperature. The experimental layout was designed based on the Taguchi’s L9 (34 Orthogonal array technique and analysis of variance (ANOVA was performed to identify the effect of the cutting parameters on the response variables. The results showed that depth of cut and cutting speed are the most important parameter influencing the tool wear. The minimum tool wear was found at cutting speed of 150 m/min, depth of cut of 0.5 mm and feed of 0.25 mm/rev. Similarly low workpiece surface temperature was obtained at cutting speed of 150 m/min, depth of cut of 0.5 mm and feed of 0.25 mm/rev. Thereafter, optimal ranges of tool wear and workpiece surface temperature values were predicted. Finally, the relationship between factors and the performance measures were developed by using multiple regression analysis.

  14. Surface roughness and cutting forces modeling for optimization of machining condition in finish hard turning of AISI 52100 steel

    Energy Technology Data Exchange (ETDEWEB)

    Azizi, Mohamed Walid; Belhadi, Salim; Yallese, Mohamed Athmane [Univ. of Guelma, Guelma (Algeria); Mabrouki, Tarek; Rigal, Jean Francois [Univ. of Lyon, Lyon (France)

    2012-12-15

    An experimental investigation was conducted to analyze the effect of cutting parameters (cutting speed, feed rate and depth of cut) and workpiece hardness on surface roughness and cutting force components. The finish hard turning of AISI 52100 steel with coated Al2O3 + TiC mixed ceramic cutting tools was studied. The planning of experiment were based on Taguchi's L27 orthogonal array. The response table and analysis of variance (ANOVA) have allowed to check the validity of linear regression model and to determine the significant parameters affecting the surface roughness and cutting forces. The statistical analysis reveals that the feed rate, workpiece hardness and cutting speed have significant effects in reducing the surface roughness; whereas the depth of cut, workpiece hardness and feed rate are observed to have a statistically significant impact on the cutting force components than the cutting speed. Consequently, empirical models were developed to correlate the cutting parameters and workpiece hardness with surface roughness and cutting forces. The optimum machining conditions to produce the lowest surface roughness with minimal cutting force components under these experimental conditions were searched using desirability function approach for multiple response factors optimization. Finally, confirmation experiments were performed to verify the pertinence of the developed empirical models.

  15. Wear Behaviour of Plasma Paste Boronized of AISI 8620 Steel with Borax and B2O3 Paste Mixtures

    Institute of Scientific and Technical Information of China (English)

    Ibrahim Gunes

    2013-01-01

    In the present study,AISI 8620 steel was plasma paste boronized (PPB) by using paste mixtures with different borax and B2O3 percentages.The PPB process was carried out in a DC plasma system at 973,1023 and 1073 K for 5 h in a gas mixture with 70% H2-30% Ar under a constant pressure of 103 Pa (10 mbar).The thickness of boride layers ranged from 15.9 to 53.6 μm depending on the temperature and process time.The hardness of the borides formed on the surface of the steel substrate and unborided steel substrate were 1648-1924 HV0.05 and 226 HV0.05,respectively.X-ray diffraction analysis of the boride layers on the surface of the samples were obtained for FeB and Fe2B phases.The wear tests on the steel were performed by using a ball-on-disc test device at room temperature with applied load of 10 N and with a shear velocity of 0.2 m/s.Wear test results showed that the highest value of wear rate was observed in the unborided sample while the lowest wear rate was observed in the PPB samples with 30% borax + 70% B4C paste at 1073 K for 5 h.

  16. Effect of electromagnetic interaction during fusion welding of AISI 2205 duplex stainless steel on the corrosion resistance

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; González-Sánchez, J.; García-Hernández, R.; Dzib-Pérez, L.; Curiel-López, F. F.

    2017-02-01

    The effect of electromagnetic interaction of low intensity (EMILI) applied during fusion welding of AISI 2205 duplex stainless steel on the resistance to localised corrosion in natural seawater was investigated. The heat affected zone (HAZ) of samples welded under EMILI showed a higher temperature for pitting initiation and lower dissolution under anodic polarisation in chloride containing solutions than samples welded without EMILI. The EMILI assisted welding process developed in the present work enhanced the resistance to localised corrosion due to a modification on the microstructural evolution in the HAZ and the fusion zone during the thermal cycle involved in fusion welding. The application of EMILI reduced the size of the HAZ, limited coarsening of the ferrite grains and promoted regeneration of austenite in this zone, inducing a homogeneous passive condition of the surface. EMILI can be applied during fusion welding of structural or functional components of diverse size manufactured with duplex stainless steel designed to withstand aggressive environments such as natural seawater or marine atmospheres.

  17. The corrosion protection of AISI(TM) 1010 steel by organic and inorganic zinc-rich primers

    Science.gov (United States)

    Danford, M. D.; Mendrek, M. J.

    1995-01-01

    The behavior of zinc-rich primer-coated AISI 1010 steel in 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR), were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electromechanical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 1010 steel cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high current between the steel cathode and both zinc-rich primer anodes (38.8 and 135.2 microns A/sq cm for the organic and inorganic primers, respectively). The results of corrosion rate determinations demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. EIS equivalent circuit parameters confirmed this conclusion. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application on solid rocket booster steel hardware.

  18. Influence of C, N and Ti concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A.; Merino, M.C.; Carboneras, M.; Coy, A.E.; Viejo, F.; Arrabal, R.; Munoz, J.A. [Departamento de Ciencia de Materiales, Facultad de Quimica, Universidad Complutense, 28040, Madrid (Spain)

    2004-07-01

    The influence of Ti, C, and N concentration on the intergranular corrosion resistance of AISI 316 Ti stainless steel has been studied. A kinetic study of the corrosion process has been carried out using gravimetric tests according to ASTM A-262 practices B and C (Streicher and Huey, respectively). The TTS diagrams were drawn as a function of alloying elements concentration (C, N and Ti). Materials characterization under several test conditions was carried out using Scanning Electron Microscopy (SEM) analysing microstructural characteristics and the attack microstructure. The chemical resistance of these steels to intergranular test was function of N, C and Ti concentration. High Ti and N concentration favoured the precipitation of TiN during the material manufacture process. N forms TiN very stable, causing the removal of Ti from the matrix and, indirectly, favouring the Cr{sub 23}C{sub 6} precipitation during the sensitization process and increasing the corrosion rate. In order to inhibit the intergranular corrosion in these materials the N and Ti concentrations must be optimised. (authors)

  19. Growth Characteristics and Kinetics of Niobium Carbide Coating Obtained on AISI 52100 by Thermal-reactive Diffusion Technique

    Institute of Scientific and Technical Information of China (English)

    YAN Shaojin; WANG Hongfu; SUN Qikun; HE Peng; PANG Chengang; WANG Huachang; WANG Ailing

    2014-01-01

    Niobium carbide coating was produced by thermal-reactive diffusion technique on AISI 52100 steel in salt bath at 1 123 K, 1 173 K, and 1 223 K for 1, 2, 4, and 6 hours. The salt consisted of borax, sodium fluoride, boron carbide, and niobium pentoxide. The presence of NbC phase on the steel surface was confirmed by X-ray diffraction analysis. Microscopic observation showed that niobium carbide coating formed on the substrate was smooth and compact. There was a distinct and flat interface between the coating and substrate. The micro-hardness of niobium carbide coating was 2892±145HV. The thickness of coating ranged from 1.6μm to 14μm. The forming kinetics of niobium carbide coating was revealed. Moreover, a contour diagram derived from experimental data was graphed for correct selection of process parameters. Some mathematical equations were built for predicting the coating thickness with predetermined processing temperature and time. The results showed that these mathematical equations are very practical as well as the kinetics equation.

  20. Application of response surface methodology for determining cutting force model in turning hardened AISI H11 hot work tool steel

    Indian Academy of Sciences (India)

    B Fnides; M A Yallese; T Mabrouki; J-F Rigal

    2011-02-01

    This experimental study is conducted to determine statistical models of cutting forces in hard turning of AISI H11 hot work tool steel (∼ 50 HRC). This steel is free from tungsten on Cr–Mo–V basis, insensitive to temperature changes and having a high wear resistance. It is employed for the manufacture of highly stressed diecasting moulds and inserts with high tool life expectancy, plastic moulds subject to high stress, helicopter rotor blades and forging dies. The workpiece is machined by a mixed ceramic tool (insert CC650 of chemical composition 70%Al23+30%TiC) under dry conditions. Based on 33 full factorial design, a total of 27 tests were carried out. The range of each parameter is set at three different levels, namely low, medium and high. Mathematical models were deduced by software Minitab (multiple linear regression and response surface methodology) in order to express the influence degree of the main cutting variables such as cutting speed, feed rate and depth of cut on cutting force components. These models would be helpful in selecting cutting variables for optimization of hard cutting process. The results indicate that the depth of cut is the dominant factor affecting cutting force components. The feed rate influences tangential cutting force more than radial and axial forces. The cutting speed affects radial force more than tangential and axial forces.

  1. Effect of carburizing temperature and time on mechanical properties of AISI/SAE 1020 steel using carbonized palm kernel shell

    Directory of Open Access Journals (Sweden)

    Olanike M. OLUWAFEMI

    2015-12-01

    Full Text Available The effects of varied carburizing temperatures and holding time on the mechanical properties of AISI/SAE1020 steel have been investigated. Standard test samples prepared from the steel sample were subjected to pack hardening process using carbonized palm kernel shell as a carburizer at 800°, 850°, 900° and 950°C and held for 60, 90 and 120 minutes, quenched in oil and temper at 500°C for 60 minutes. After pack hardening process, the test samples were subjected to tensile, impact and hardness tests. and from the data obtained Ultimate tensile strength (UTS and impact strength were calculated, the case and the core hardness of the carburized samples were taken and optical microscope was also used to observe the micro structural features of the case hardened, quenched and tempered samples. It was observed that at 800°, 850° and 900°C, the UTS and the micro hardness initially reduces to minimum and then increased as the carburizing temperature increased, but at 950°C, it was observed that the UTS increases with increase in holding time. It was concluded that the optimum combination of mechanical properties is achieved at the carburizing temperature of 950°C soaked for 120 minutes followed by oil quenching and tempered at 500°C for 60 minutes.

  2. Effect of contents oil temperature and flow rate in the electrochemical corrosion of the AISI-SAE1020-steel

    Science.gov (United States)

    Cedeño, M. L.; L, E. Vera; Pineda T, Y.

    2017-01-01

    Primary causes of corrosion in components and equipment used in the petroleum industry are due to the density differences present in the multiphase system Water/Hydrocarbon/CO2 as well as the presence of weak particles of carbonic acid. The present research is focus on the study of the corrosion rate of the steel AISI-SAE 1020 under a saturated CO2 multiphase system. The effects of fluid speed, temperature and oil content on the steel corrosion were carried out in an electrode of rotator cylinder and also using electrochemical impedance spectroscopy, and potentiodynamic polarization measurements. The results show that the effect of oil content in the rate of steel corrosion is inversely proportional with the speed of the rotor. Our observations indicate that increasing the rotor speed in systems containing 60% oil or higher produce a simultaneous increase in the degradation rate of materials. Similarly, temperatures higher than 60°C generate layers of siderite that reduce the electrochemical effect.

  3. Tribocorrosion Failure Mechanism of TiN/SiOx Duplex Coating Deposited on AISI304 Stainless Steel

    Directory of Open Access Journals (Sweden)

    Qiang Chen

    2016-11-01

    Full Text Available TiN/SiOx duplex coatings were synthesized on AISI304 stainless steel by plasma immersion ion implantation and deposition (PIIID followed by radio frequency magnetron sputtering (RFMS. The microstructure and tribocorrosion failure behaviors of the duplex coatings were investigated by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, reciprocating-sliding tribometer, and electrochemical tests. The as-deposited duplex coating had a two-layered columnar growth structure consisting of face-centered cubic TiN and amorphous SiOx. Sliding tests showed that the TiN interlayer had good adhesion with the substrate, but the SiOx layer suffered from severe delamination failure. Friction force induced a number of micro-cracks in the coating, which provided channels for the diffusion of NaCl solution. The tribocorrosion test showed that the duplex coating exhibited a lower wear-performance in NaCl solution than in ambient atmosphere. Multi-scale chloride ion corrosion occurred simultaneously and substantially degraded the bonding strength of the columnar crystals or neighboring layers. Force-corrosion synergy damage eventually led to multi-degradation failure of the duplex coating. The presented results provide a comprehensive understanding of the tribocorrosion failure mechanism in coatings with duplex architecture.

  4. Analyzing the Effectiveness of Microlubrication Using a Vegetable Oil-Based Metal Working Fluid during End Milling AISI 1018 Steel

    Directory of Open Access Journals (Sweden)

    Vasim Shaikh

    2014-01-01

    Full Text Available Microlubrication minimizes the exposure of metal working fluids to the machining operators leading to an economical, safer, and healthier workplace environment. In this study, a vegetable oil-based lubricant was used to conduct wear analysis and to analyze the effectiveness of microlubrication during end milling AISI 1018 steel. A solid carbide cutting tool with bright oxide finish was used with varying cutting speed and feed rate having a constant depth of cut. Abrasion was the dominant wear mechanism for all the cutting tools under consideration. Other than abrasion, sliding adhesive wear of the workpiece materials was also observed. The scanning electron microscope investigation of the used cutting tools revealed microfatigue cracks, welded microchips, and unusual built-up edges on the cutting tools flank and rake side. A full factorial experiment was conducted and regression models were generated for both the sides of tool flank wear. The study shows that with a proper selection of the cutting parameters it is possible to obtain higher tool life.

  5. A study on the microstructure and mechanical properties of AISI D2 tool steel modified by niobium

    Energy Technology Data Exchange (ETDEWEB)

    Hamidzadeh, M.A.; Meratian, M. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Mohammadi Zahrani, M., E-mail: iut.mohammadi@gmail.com [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2012-10-30

    The microstructure and mechanical properties of AISI D2 tool steel with up to 1.5 wt% niobium additions were investigated. The microstructural evolutions were characterized by means of optical microscopy and scanning electron microscopy techniques. Mechanical properties of the samples were measured using tensile testing, hardness measurements and Charpy impact test. The results indicated that modification of the microstructure was effectively achieved through the addition of 1.5 wt% of niobium, which refined the prior-austenite grains and decreased the volume fraction of eutectic carbides. Also, the eutectic carbide network tended to break thereby forming blocky and ribbon-like morphologies in the eutectic structures. The ductility and impact toughness of the niobium-contained steels were increased considerably and reached to about 5.8% and 15 J/cm{sup 2}, respectively. Generally, the results of this study suggest that niobium can be used as an alloying element to significantly enhance the ductility and impact toughness of D2 tool steel without affecting the hardness.

  6. Comparison of the Electrochemical Behavior of Ti and Nanostructured Ti-Coated AISI 304 Stainless Steel in Strongly Acidic Solutions

    Science.gov (United States)

    Attarzadeh, Farid Reza; Elmkhah, Hassan; Fattah-Alhosseini, Arash

    2017-02-01

    In this study, the electrochemical behaviors of pure titanium (Ti) and nanostructured (NS) Ti-coated AISI 304 stainless steel (SS) in strongly acidic solutions of H2SO4 were investigated and compared. A type of physical vapor deposition method, cathodic arc evaporation, was applied to deposit NS Ti on 304 SS. Scanning electron microscope and X-ray diffraction were used to characterize surface coating morphology. Potentiodynamic polarization, electrochemical impedance spectroscopy, and Mott-Schottky (M-S) analysis were used to evaluate the passive behavior of the samples. Electrochemical measurements revealed that the passive behavior of NS Ti coating was better than that of pure Ti in 0.1 and 0.01 M H2SO4 solutions. M-S analysis indicated that the passive films behaved as n-type semiconductors in H2SO4 solutions and the deposition method did not affect the semiconducting type of passive films formed on the coated samples. In addition, this analysis showed that the NS Ti coating had lower donor densities. Finally, all electrochemical tests showed that the passive behavior of the Ti-coated samples was superior, mainly due to the formation of thicker, yet less defective passive films.

  7. Correlation between surface physicochemical properties and the release of iron from stainless steel AISI 304 in biological media.

    Science.gov (United States)

    Hedberg, Yolanda; Karlsson, Maria-Elisa; Blomberg, Eva; Odnevall Wallinder, Inger; Hedberg, Jonas

    2014-10-01

    Stainless steel is widely used in biological environments, for example as implant material or in food applications, where adsorption-controlled ligand-induced metal release is of importance from a corrosion, health, and food safety perspective. The objective of this study was to elucidate potential correlations between surface energy and wettability of stainless steel surfaces and the release of iron in complexing biological media. This was accomplished by studying changes in surface energies calculated from contact angle measurements, surface oxide composition (X-ray photoelectron spectroscopy), and released iron (graphite furnace atomic absorption spectroscopy) for stainless steel grade AISI 304 immersed in fluids containing bovine serum albumin or citric acid, and non-complexing fluids such as NaCl, NaOH, and HNO3. It was shown that the surface wettability and polar surface energy components were all influenced by adventitious atmospheric carbon (surface contamination of low molecular weight), rather than differences in surface oxide composition in non-complexing solutions. Adsorption of both BSA and citrate, which resulted in ligand-induced metal release, strongly influenced the wettability and the surface energy, and correlated well with the measured released amount of iron.

  8. Enhancing the corrosion resistance of dentistry drills by plasma immersion nitrogen in implantation of AISI 434-based SS

    Energy Technology Data Exchange (ETDEWEB)

    Munoz C, A.E.; Lopez C, R.; Fuentes G, D.; Valencia A, R. [UAEM, Facultad de Quimica, Instituto Literario 100, Toluca (Mexico)]. e-mail: rlc@nuclear.inin.mx

    2007-07-01

    In order to enhance the resistance to the pitting corrosion due to asepsis processes and to avoid structural fractures in dentistry drills, a plasma immersion ion implantation (PIII) treatment using nitrogen has been performed. The selected drill samples, made of AISI 434 based stainless steel with a 0.670 mm diameter, were treated at a -1kV bias between 350 C and 450 C, this temperature being controlled by both a 20-50 {mu}s pulse width and a 200-1000 Hz repetition rate in the bias. The drills were analysed by cyclic potentiodynamic tests showing a good pitting corrosion resistance when treated at around 400 C, as follows from a resulting very low hysteresis loop. Yet, the resistance appears somehow diminished by the presence of sputtering when processed at temperatures near 450 C. It is also found that the PIII nitriding effectiveness appears to be limited by the appearance of uniform corrosion. Finally, X-ray diffraction of the samples has revealed the presence of two new phases, namely {epsilon}-Fe{sub 2}N and Fe{sub 4.4}N, while scanning electron microscopy of the treated surfaces has suggested a sputtering enhancement at the highest temperatures. (Author)

  9. The role of martensitic transformation on bimodal grain structure in ultrafine grained AISI 304L stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Sabooni, S., E-mail: s.sabooni@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of); Karimzadeh, F.; Enayati, M.H. [Department of Materials Engineering, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of); Ngan, A.H.W. [Department of Mechanical Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2015-06-11

    In the present study, metastable AISI 304L austenitic stainless steel samples were subjected to different cold rolling reductions from 70% to 93%, followed by annealing at 700 °C for 300 min to form ultrafine grained (UFG) austenite with different grain structures. Transmission electron microscopy (TEM) and nanoindentation were used to characterize the martensitic transformation, in order to relate it to the bimodal distribution of the austenite grain size after subsequent annealing. The results showed that the martensite morphology changed from lath type in the 60% rolled sample to a mixture of lath and dislocation-cell types in the higher rolling reductions. Calculation of the Gibbs free energy change during the reversion treatment showed that the reversion mechanism is shear controlled at the annealing temperature and so the morphology of the reverted austenite is completely dependent on the morphology of the deformation induced martensite. It was found that the austenite had a bimodal grain size distribution in the 80% rolled and annealed state and this is related to the existence of different types of martensite. Increasing the rolling reduction to 93% followed by annealing caused changing of the grain structure to a monomodal like structure, which was mostly covered with small grains of around 300 nm. The existence of bimodal austenite grain size in the 80% rolled and annealed 304L stainless steel led to the improvement of ductility while maintaining a high tensile strength in comparison with the 93% rolled and annealed sample.

  10. Martensite phase reversion-induced nano/ ultrafine grained AISI 304L stainless steel with magnificent mechanical properties

    Directory of Open Access Journals (Sweden)

    Mohammad Shirdel

    2015-06-01

    Full Text Available Austenitic stainless steels are extensively used in various applications requiring good corrosion resistance and formability. In the current study, the formation of nano/ ultrafine grained austenitic microstructure in a microalloyed AISI 304L stainless steel was investigated by the advanced thermomechanical process of reversion of strain-induced martensite. For this purpose, samples were subjected to heavy cold rolling to produce a nearly complete martensitic structure. Subsequently, a wide range of annealing temperatures (600 to 800°C and times (1 to 240 min were employed to assess the reversion behavior and to find the best annealing condition for the production of the nano/ultrafine grained austenitic microstructure. Microstructural characterizations have been performed using X-ray diffraction (XRD, scanning electron microscopy (SEM, and magnetic measurement, whereas the mechanical properties were assessed by tensile and hardness tests. After thermomechanical treatment, a very fine austenitic structure was obtained, which was composed of nano sized grains of ~ 85 nm in an ultrafine grained matrix with an average grain size of 480 nm. This microstructure exhibited superior mechanical properties: high tensile strength of about 1280 MPa with a desirable elongation of about 41%, which can pave the way for the application of these sheets in the automotive industry.

  11. Separation of surface, subsurface and volume fatigue damage effects in AISI 348 steel for power plant applications

    Energy Technology Data Exchange (ETDEWEB)

    Klein, Martin; Nowak, David; Walther, Frank [Technical Univ. Dortmund (Germany). Dept. of Materials Test Engineering (WPT); Starke, Peter [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Boller, Christian [Saarland Univ., Saarbruecken (Germany). Chair of Non-Destructive Testing and Quality Assurance; Fraunhofer IZFP, Saarbruecken (Germany)

    2016-08-01

    A wide range of industries including energy, chemistry, pharmacy, textiles, food and drink, pulp and paper, etc. is using stainless steels. Metastable austenitic steels such as used in power plants and chemical industry are subjected to cyclic mechanical and thermal loading in air as well as under the influence of corrosive media. This paper provides an overview on different nondestructive and electrochemical measurement techniques, which allow differentiating fatigue damage effects in total strain controlled multiple and constant amplitude tests with respect to damage appearance on surface, in subsurface area as well as in volume of specimens or components microstructure. In addition to conventional mechanical stress-strain hysteresis curves, electrical resistance, magnetic and open circuit potential measurements have been applied to characterize the cyclic deformation behavior of the metastable austenitic steel AISI 348 (X10CrNiNb18-9) in laboratory air and in distilled water. Based on these results obtained, the paper provides an outlook on the possibility for an efficient (remaining) fatigue life evaluation approach, which is adapted to the needs of the application areas.

  12. Standard test method for electrochemical reactivation (EPR) for detecting sensitization of AISI type 304 and 304L stainless steels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 This test method covers a laboratory procedure for conducting an electrochemical reactivation (EPR) test on AISI Type 304 and 304L (UNS No. S30400 and S30403, respectively) stainless steels. This test method can provide a nondestructive means of quantifying the degree of sensitization in these steels (1, 2, 3). This test method has found wide acceptance in studies of the effects of sensitization on intergranular corrosion and intergranular stress corrosion cracking behavior (see Terminology G15). The EPR technique has been successfully used to evaluate other stainless steels and nickel base alloys (4), but the test conditions and evaluation criteria used were modified in each case from those cited in this test method. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this...

  13. Laser-assisted direct joining of AISI304 stainless steel with polycarbonate sheets: Thermal analysis, mechanical characterization, and bonds morphology

    Science.gov (United States)

    Lambiase, F.; Genna, S.

    2017-02-01

    Laser-Assisted Metal and Plastic bonding (LAMP) of AISI304 sheets with polycarbonate sheets is investigated in this work. The process was performed by means of a high power diode laser with a maximum power of 200 W. The study introduces an integrated experimental approach aimed at understanding how the main process conditions (laser power and scanning speed) influence the direct-bonds quality, dimensions and presence of defects. To this end, the bonds dimension, shear strength, formation and dimension of bubbles in the bonded region were related to the temperature measurements and process parameters. According to the achieved results, the processing window that enables a good adhesion of the two materials is relatively small; this is due the activation of the adhesion phenomena that require overcoming an energy threshold. However, excessive energy levels reduce the bonds strength due to the increase in defects (bubbles) dimension that may combine (coalescence) leading to the formation of a central tunnel where the two substrates are completely detached.

  14. Influence of the cutting parameters on flank wear of coated inserts during turning of AISI 316L

    Directory of Open Access Journals (Sweden)

    Yusimit Zamora Hernández

    2015-03-01

    Full Text Available (Received: 2015/01/20 - Accepted: 2015/03/25The continuous improvement of manufacturing processes is critical to achieve optimum levels of productivity, quality and cut production of components and products. This research aims to determine the cutting tool flank wearing progression, during a high speed dry turning, for AISI 316L steel parts. Experimental data were acquired using two cutting feed levels, two material levels, three cutting speeds, and four principal cutting times. A scanning electron microscope (SEM was used to measure and analyze the wear of the cutting tools. Results were compared using analysis of variance and multiple regression for describing the relation between the variables used in the study. The analysis showed that the three layers coating insert did not exceed the end of life wearing criterion, while the one layer insert suffered a catastrophic wearing at the highest cutting speed. It was found that a relation exists between the experimental data and the predicted values for flank wear with a general average error of 4.1182%.

  15. Surface interactions of a W-DLC-coated biomedical AISI 316L stainless steel in physiological solution.

    Science.gov (United States)

    Antunes, Renato A; de Lima, Nelson Batista; Rizzutto, Márcia de Almeida; Higa, Olga Zazuco; Saiki, Mitiko; Costa, Isolda

    2013-04-01

    The corrosion stability of a W-DLC coated surgical AISI 316L stainless steel in Hanks' solution has been evaluated. Particle induced X-ray emission (PIXE) measurements were performed to evaluate the incorporation of potentially bioactive elements from the physiological solution. The film structure was analyzed by X-ray diffractometry and micro-Raman spectroscopy. The wear behavior was assessed using the sphere-on-disc geometry. The in vitro biocompatibility of the W-DLC film was evaluated by cytotoxicity tests. The corrosion resistance of the stainless steel substrate decreased in the presence of the PVD layer. EIS measurements suggest that this behavior was closely related to the corrosion attack through the coating pores. PIXE measurements revealed the presence of Ca and P in the W-DLC film after immersion in Hanks' solution. This result shows that the PIXE technique can be applied to identify and evaluate the incorporation of bioactive elements by W-DLC films. The film showed good wear resistance and biocompatibility.

  16. Biocompatibility studies of low temperature nitrided and collagen-I coated AISI 316L austenitic stainless steel.

    Science.gov (United States)

    Martinesi, M; Stio, M; Treves, C; Borgioli, F

    2013-06-01

    The biocompatibility of austenitic stainless steels can be improved by means of surface engineering techniques. In the present research it was investigated if low temperature nitrided AISI 316L austenitic stainless steel may be a suitable substrate for bioactive protein coating consisting of collagen-I. The biocompatibility of surface modified alloy was studied using as experimental model endothelial cells (human umbilical vein endothelial cells) in culture. Low temperature nitriding produces modified surface layers consisting mainly of S phase, the supersaturated interstitial solid solution of nitrogen in the austenite lattice, which allows to enhance surface microhardness and corrosion resistance in PBS solution. The nitriding treatment seems to promote the coating with collagen-I, without chemical coupling agents, in respect of the untreated alloy. For biocompatibility studies, proliferation, lactate dehydrogenase levels and secretion of two metalloproteinases (MMP-2 and MMP-9) were determined. Experimental results suggest that the collagen protection may be favourable for endothelial cell proliferation and for the control of MMP-2 release.

  17. Electrochemical characterization of AISI 316L stainless steel in contact with simulated body fluid under infection conditions.

    Science.gov (United States)

    López, Danián Alejandro; Durán, Alicia; Ceré, Silvia Marcela

    2008-05-01

    Titanium and cobalt alloys, as well as some stainless steels, are among the most frequently used materials in orthopaedic surgery. In industrialized countries, stainless steel devices are used only for temporary implants due to their lower corrosion resistance in physiologic media when compared to other alloys. However, due to economical reasons, the use of stainless steel alloys for permanent implants is very common in developing countries. The implantation of foreign bodies is sometimes necessary in the modern medical practice. However, the complex interactions between the host and the can implant weaken the local immune system, increasing the risk of infections. Therefore, it is necessary to further study these materials as well as the characteristics of the superficial film formed in physiologic media in infection conditions in order to control their potential toxicity due to the release of metallic ions in the human body. This work presents a study of the superficial composition and the corrosion resistance of AISI 316L stainless steel and the influence of its main alloying elements when they are exposed to an acidic solution that simulates the change of pH that occurs when an infection develops. Aerated simulated body fluid (SBF) was employed as working solution at 37 degrees C. The pH was adjusted to 7.25 and 4 in order to reproduce normal body and disease state respectively. Corrosion resistance was measured by means of electrochemical impedance spectroscopy (EIS) and anodic polarization curves.

  18. Pengaruh Variasi Temperatur Austenisasi pada Proses Heat Treatment Quenching Terhadap Sifat Mekanik dan Struktur Mikro Friction Wedge AISI 1340

    Directory of Open Access Journals (Sweden)

    Fahmi Aziz Husain

    2013-09-01

    Full Text Available Permasalahan yang sering timbul dalam pembuatan friction wedge AISI 1340 adalah adanya Crack yang terjadi setelah proses quenching dalam pembuatan friction wedge. Kemungkinan penyebab kegagalan yang terjadi yakni kurang tepatnya perlakuan panas yang dilakukan.Oleh karena itu perlu adanya suatu penelitian untuk mencari perlakuan panas yang tepat. . Metodologi yang digunakan adalah heat treatment quenching dengan variasi temperatur austenisasi 830°C, 850°C, 870°C dan 920°C dengan waktu penahanan 20 menit, kemudian didinginkan cepat dengan media pendingin oli. Hasil dari penelitian ini adalah semua spesimen hasil treatment memenuhi standar kekerasan friction wedge. Nilai kekerasan naik seiring naiknya temperatur austenisasi. Hasil paling baik didapat dari spesimen heat treatment quenching di media pendingin oli pada temperatur austenisasi 830oC dengan nilai kekerasan 458 BHN, tidak ada Crack yang terjadi dan memiliki nilai elongasi yang paling rendah yaitu 0,43%, sehingga bisa tahan pada temperatur kerja daripada spesimen yang lain. Struktur mikro yang dihasilkan berupa martensit dan austenit sisa. Dari pengujian XRD didapatkan fasa Fe1.91 C0.09 (Martensit BCT dan Fe15.1 C (Austenit FCC.

  19. Electrochemical study of AISI 304 stainless steel during the exposure at the disinfectant solutions with fungal suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Stoica, M.; Bruma, M. [Department of Biochemistry and Technologies, Faculty of Food Science and Engineering, ' ' Dunarea de Jos' ' University of Galati, 111 Domneasca Street, 800201 Galati (Romania); Carac, G. [Department of Chemistry, Faculty of Sciences, ' ' Dunarea de Jos' ' University of Galati, 47 Domneasca Street, 800008 Galati (Romania)

    2010-12-15

    The effect of fungal suspensions on the disinfectant solution (Actisept with sodium dichloroisocyanurate as active substance, which releases 140 ppm active chlorine) and the corrosion behavior of type AISI 304 stainless steel (SS) were evaluated through linear polarization. The work presents a study of biocide Actisept solution as reference solution and the mixed solutions: reference biocide Actisept solution with three fungal suspensions (10 vol%), Aspergillus niger, Candida mycoderma, and Saccharomyces cerevisiae. The fungal suspension has an important influence on the synergistic effect of the SS corrosion in the following order: Saccharomyces cerevisiae > Candida mycoderma > Aspergillus niger. The E{sub corr} values from the mixed solutions decreased with immersion time of the samples. In the case of Aspergillus niger, the corrosion rate was lower than that of any other type of fungal suspension tested, because the arrangement in solutions, the size and composition of Aspergillus niger spores were more favorable to protect the spores of the chemical and the electrical stressing. The results showed that there is a synergistic effect between the active substances from the disinfectant, fungal suspensions and applied potential, thus this effect can be taken into consideration for the hygienic and safety food industry. (Copyright copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Prediction for pitting corrosion of AISI type 403 stainless steel in chloride-containing borate buffer solution

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Yancheng [Pennsylvania State Univ. (United States); Macdonald, D.D. [Pennsylvania State Univ. (United States). Center for Electrochemical Science and Technology; Urquidi-Macdonald, M. [Pennsylvania State Univ. (United States). Engineering Science and Mechanics; Engelhardt, G.R. [OLI Systems, Inc. (United States); Dooley, R.B. [Electric Power Research Inst., Palo Alto, CA (United States). Materials and Chemistry Performance Dept.

    2007-07-15

    The prediction of pitting corrosion damage on low-pressure steam turbine (LPST) blade surfaces has been investigated experimentally and the results have been interpreted in terms of the Point Defect Model (PDM) for passivity breakdown and the nucleation of pits. Experimental relationships between the critical breakdown potential (Vc) and the chloride activity aCl- and pH have demonstrated the applicability of the PDM for describing passivity breakdown on AISI Type 403 stainless steel (SS), a commonly employed blade alloy in LPSTs, in chloride-containing borate buffer solutions. The model parameter values, as determined by optimization of the PDM on passivity breakdown data, may be used to predict the nucleation and accumulation of pitting damage on LPST blades under simulated turbine shutdown conditions. In order to evaluate the predictions, integral damage functions (IDFs) and extreme value distributions in pit depth have been measured on samples taken from failed blades recovered from the field (Texas Genco). These data are being used to test the predictions of Damage Function Analysis (DFA), which is based on the PDM and on deterministic models for pit growth and delayed repassivation. However, the success of this analysis critically depends on our ability to define the corrosion evolutionary path. (orig.)

  1. INFLUENCE OF PLASMA NITRIDING ON THE CORROSION BEHAVIOUR AND ADHESION OF DLC COATINGS DEPOSITED ON AISI 420 STAINLESS STEEL

    Directory of Open Access Journals (Sweden)

    Jorge N. Pecina

    2016-06-01

    Full Text Available In this work the corrosion behavior and adhesion of two DLC (“Diamond Like Carbon” films (“Soft” and “Hard” were studied. Both coatings were deposited by PACVD (“Plasma Assisted Chemical Vapour Deposition” on plasma-nitrided and non-nitrided AISI 420 stainless steel. Raman spectroscopy was conducted and surface hardness was measured. The microstructure by OM and SEM, was observed. Adhesion tests were performed with C. Rockwell indentation test. Salt Spray and immersion were performed in HCl. The “Soft” coating was 20 μm thick, the “Hard” film was about 2.5 μm. The hardness was of 500 HV in the “Soft” DLC and 1400 HV in the “Hard” DLC. Both coatings presented low friction coefficient and good adhesion when they were deposited on nitrided steel. Also presented good resistance to atmospheric corrosion. HCl DLC degradation slowed rapidly introduced uncoated samples.

  2. Surface Properties of Fe4N Compounds Layer on AISI 4340 Steel Modified by Pulsed Plasma Nitriding

    Institute of Scientific and Technical Information of China (English)

    J.C.Díaz-Guillén; G.Vargas-Gutiérrez; E.E.Granda-Gutiérrez; J.S.Zamarripa-Pi(n)a; S.I.Pérez-Aguilar; J.Candelas-Ramirez; L.(A)lvarez-Contreras

    2013-01-01

    In this work,the effect of nitriding current density on hardness,crystalline phase composition,layer thickness and corrosion rate of AISI 4340 steel has been studied.X-ray diffraction analysis shows that thin layers formed during nitriding process are constituted of γ-Fe4N for samples processed between 1 and 2.5 mA/cm2.Thickness of nitrided layer increases proportionally to current density (0 μm for 0.5 mA/cm2 to 15 μm for 2.5 mA/cm2).Plasma nitriding increased the surface hardness from 300 HV50g for untreated sample,to around 800HV50g for nitrided samples at 1 mA/cm2.While the untreated samples exhibited a corrosion rate of 0.153 mm per year,the corrosion performance was improved up to 0.03 mm per year at current densities above 1 mA/cm2,which is about one fifth of the corrosion rate of the untreated sample.

  3. Influence of austenitizing temperature on microstructure and mechanical properties of AISI 431 martensitic stainless steel electron beam welds

    Energy Technology Data Exchange (ETDEWEB)

    Rajasekhar, A. [Department of Mechanical Engineering, SVITS, Mahaboob Nagar 509 001 (India)], E-mail: adula.rajasekhar@rediffmail.com; Madhusudhan Reddy, G.; Mohandas, T. [Defence Metallurgical Research Laboratory, Hyderabad 500 058 (India); Murti, V.S.R. [Department of Mechanical Engineering, SVITS, Mahaboob Nagar 509 001 (India)

    2009-05-15

    The relative effects of various austenitizing temperatures on microstructure and mechanical properties of electron beam welds of AISI 431martensitic stainless steel were studied. The post-weld heat treatments consist of austenitizing the weld samples for 1 h at various temperatures, i.e., at 950 deg. C, 1000 deg. C, 1050 deg. C, 1100 deg. C and at 1150 deg. C and air cooling followed by double tempering, i.e., tempering at 670 + 600 deg. C. In the as-welded condition the microstructure contains dendritic structure with ferrite network and retained austenite in a matrix of un-tempered martensite. The prior austenite grain size increased with increase in austenitizing temperature. Parent metal grain size was coarser as compared to grain size in the weld zone in respective conditions. Retained austenite content increased with increase in the austenitizing temperature. Presence of undissolved carbides was observed in welds and parent metal austenitized up to 1000 deg. C and they dissolved at austenitizing temperature {>=} 1050 deg. C. Coarsening of martensite laths was observed after tempering. The martensite laths were coarser in the samples subjected to higher austenitizing temperatures. Optimum mechanical properties, i.e., strength, hardness and toughness were observed when austenitized between 1050 deg. C and 1100 deg. C followed by tempering. Austenitizing at 1150 deg. C and tempering resulted in inferior mechanical properties. The mechanism for the observed trends is discussed in relation to the microstructure, fracture features and mechanical properties.

  4. Physisorption of ammonia on AISI 304L stainless steel at different surface temperature under high vacuum conditions

    Directory of Open Access Journals (Sweden)

    A. de Castro

    2016-12-01

    Full Text Available The physisorption of ammonia molecules (sticking on the walls of a stainless steel pipe (AISI 304L has been studied at different wall temperatures (323-473K. The total amount of ammonia that is retained on the walls, once equilibrium is reached, has been measured by differentially-pumped mass spectrometry in gas exposure laboratory experiments. The results show ammonia retentions in the range of μg/cm2 resulting in a multilayer adsorption with lower amounts of stuck ammonia at higher temperatures of the stainless steel surface. The sticking coefficient follows an exponential decay evolution with time. The activation energy of the process has been estimated by an Arrhenius fit, assuming that the characteristic time for this decay is inversely proportional to the kinetic adsorption constant. A value of 0.15eV per ammonia molecule has been obtained, being in agreement with nominal values for the physisorption of small molecules or atoms (CO, N2, Ar… that can be found in the specialized literature. The implication of these results in the possible extrapolation to the ITER vacuum system under nitrogen seeded plasma operation is also addressed.

  5. sistema Web con JSP

    Directory of Open Access Journals (Sweden)

    César Viloria Núñez

    2014-01-01

    Full Text Available Este artículo presenta el desarrollo de un sistema de información que permite la adquisición y la administración de información relacionada con los signos vitales como la presión arterial, la frecuencia cardiaca y respiratoria, y la saturación de oxígeno en la sangre de un paciente. La implementación del sistema se basa en una solución Web, permitiendo así que médicos especialistas puedan monitorear a sus pacientes desde cualquier punto conectado a la red en tiempo real y, al mismo tiempo, dar indicaciones críticas al personal médico que se encuentra en el lugar con el paciente.

  6. Transporte forestal con cables

    OpenAIRE

    Anaya L. Héctor J.

    2012-01-01

    La explotación forestal es un problema fundamentalmente de transporte. El apeo y la preparación de las trozas, aunque a veces presentan algunas dificultades, son operaciones fáciles de resolver comparadas con la operación de transporte la cual absorbe del 60% al 70% o más del costo total del aprovechamiento del bosque. El 30% o 40% restante es absorbido por las faenas previas de apeo y troceo.

  7. Encuentros con Elena Poniatowska

    OpenAIRE

    Uzquiza González, José Ignacio

    2008-01-01

    El autor analiza, desde su encuentro con Elena Poniatowska, la vertiente de la literatura testimonial como literatura de mujeres. Un análisis interior de la relación entre realidad y ficción, entre Elena, Jesusa o Tinísima. The author analyzes testimonial literature from the perspective of female literature through his meeting with Elena Poniatowska. An analysis of reality vs. Fiction in Elena, Jesusa and Tinisima.

  8. pacientes con falla cardiaca

    Directory of Open Access Journals (Sweden)

    Diana Marcela Achury Saldaña

    2007-01-01

    Full Text Available Objetivo: determinar la adherencia al tratamiento de pacientes con falla cardiaca hospitalizados, al aplicar un plan educativo quefomenta el autocuidado.Método: estudio cuasiexperimental (entrevistas enfermera-paciente realizado entre diciembre de 2004 y mayo de 2006, con unamuestra de 50 pacientes seleccionados por conveniencia. Se diseñó un instrumento para evaluar los comportamientos de los pacientes,con base en algunos resultados de la adherencia y sus respectivos indicadores de la taxonomía NOC (Nursing out comes classification. Laadherencia al tratamiento fue medida en dos momentos: el primero durante la hospitalización, seguido de la aplicación del plan educativoantes del alta, que proporcionaba información en el manejo de su enfermedad desde una dimensión física, psicológica y social quepromueve el autocuidado; y el segundo un mes después del alta en su domicilio.Resultados: diferencias estadísticamente significativas (P=0,0001 que demuestran cómo mediante la capacitación al paciente enel manejo de su tratamiento farmacológico y no farmacológico, el establecimiento de una sana relación entre el profesional de enfermeríay el paciente, y la participación de la familia, se logra una total adherencia al tratamiento.Conclusiones: para lograr una adherencia total del paciente con falla cardiaca al tratamiento es necesario un proceso educativo y unseguimiento continuo y personalizado que motive permanentemente al paciente y se le reconozca el papel protagónico en su cuidado y manejo de la enfermedad.

  9. Lectura con adolescentes

    Directory of Open Access Journals (Sweden)

    Silvia Méndez Anchía

    2007-01-01

    Full Text Available Con base en la premisa de que la lectura de textos literarios tiene una función formadora y que esta se acentúa en la adolescencia, me propongo demostrar que el cuento “Rapunzel” puede utilizarse como estrategia para explorar algunas situaciones que los sujetos adolescentes perciben como particulares en relación con su vida, pero que se inscriben dentro de grandes problemáticas estudiadas por varias disciplinas. Para ello, he identificado, desde dos marcos de referencia (sociológico y psicoanalítico, diversas problemáticas y discursos que se desprenden de la lectura del cuento realizada por dos mujeres adolescentes, quienes respondieron una guía de lectura y participaron en una entrevista a profundidad. Concluyo que la lectura y comentario del cuento hacen posible que una serie de experiencias que los sujetos adolescentes viven como únicas (como el embarazo de una amiga, las críticas de las personas adultas y las exigencias de padres y madres, ingresen en el circuito de los conocimientos generales al relacionarlas con los discursos y problemáticas en que se inscriben (por ejemplo, el discurso de la “crisis” de la adolescencia, el enfoque de derechos humanos, el mundo fantasmático materno. Por ello, recomiendo la lectura y comentario de textos literarios como estrategia didáctica para contribuir a la elaboración de la subjetividad de personas adolescentes.

  10. Decomposition of Expanded Austenite in AISI 316 L Stainless Steel Nitrided at 450 ℃%450℃渗氮AISI 316 L不锈钢中膨胀奥氏体的分解

    Institute of Scientific and Technical Information of China (English)

    F.A.P.Fernandes; L.C.Casteletti; G.E.Totten; J.Gallego

    2014-01-01

    Expanded austenite (γN ),which can be produced during plasma nitriding of austenitic stainless steels, provides high levels of strength,toughness and corrosion resistance by comparison with traditional nitride layers. However,expanded austenite properties can be lost due to decomposition caused its thermodynamic metastability. In the present work,austenitic stainless AISI 316L steel was plasma nitrided at 450 ℃ for 5 h at 500 Pa and microstructurally characterised by X-ray diffraction (XRD ),and optical and transmission electron microscopy (TEM)which confirmed the presence of fcc expanded austenite with a lattice parameter up to 9.5% larger than untreated austenite.TEM analyses of thin foils showed that fine nitrides were formed in the N layer and some areas were observed with a singular lamellar morphology very similar to the pearlite colonies found in carbon steels. Selected area electron diffraction (SAED)analysis suggests that these areas are composed of bcc ferrite and cubic chromium nitrides produced after a localised decomposition of the expanded austenite layer.Amorphous expanded austenite was observed in some areas of the investigated samples.The occurrence of N decomposition was associated with microsegregation of ferrite stabilisers (Cr,Mo)and depletion of an austenite stabiliser (Ni)in localised regions of the expanded austenite layer.%奥氏体不锈钢等离子渗氮时会形成膨胀奥氏体(γN),其强度、韧性和耐蚀性均高于传统的氮化物层。然而,膨胀奥氏体在热力学上是亚稳的,其性能会因其发生分解而降低。本文对AISI 316L 不锈钢进行了等离子渗氮,工艺为450℃×5 h,压力500 Pa。对渗氮后试样采用XRD、OM和TEM等进行了显微组织表征。试验结果证明了面心立方膨胀奥氏体的存在,其晶格常数比未经渗氮奥氏体增加多达9.5%。薄片试样的TE M分析表明,N层中有细小的氮化物形成,并且发现一些区域呈奇特的

  11. Solidificação da zona de fusão na soldagem do AISI 304 com inconel 600 por laser de Nd: YAG Microstructure development in Nd: YAG laser welding of AISI 304 and Inconel 600

    Directory of Open Access Journals (Sweden)

    Maurício David M. das Neves

    2009-06-01

    Full Text Available Neste trabalho estudou-se a morfologia de solidificação da zona de fusão, numa junta formada a partir de materiais dissimilares, composta por aço inoxidável austenítico AISI 304 e por liga de níquel Inconel 600, soldada com laser pulsado de Nd:YAG. Os parâmetros do feixe laser e do sistema óptico foram selecionados, visando obter uma solda com penetração total e bom acabamento superficial. A caracterização microestrutural foi realizada por microscopia ótica, onde se observou uma zona de fusão com penetração total do tipo keyhole, a presença de pequenos poros e a ausência de trincas. As juntas soldadas foram caracterizadas também, por meio de microscopia eletrônica de varredura (MEV. Medidas realizadas por espectrometria de raios X por dispersão de energia na zona de fusão indicaram uma distribuição levemente heterogênea de níquel e ferro. Observou-se que o início de solidificação da zona de fusão ocorreu por meio de crescimento epitaxial. A morfologia de solidificação da ZF foi basicamente dendrítica e celular sendo, influenciada pelo gradiente de temperatura, velocidade de solidificação e composição química. As variações de composição química e da morfologia de solidificação não alteraram significativamente os valores de microdureza Vickers na zona de fusão. Resultados obtidos nos ensaios de tração indicaram valores de eficiência de soldagem adequados.An autogenous laser welding of dissimilar materials involving AISI 304 austenitic stainless steels and Inconel 600 nickel alloy was investigated in this study. Hence, the aim of this investigation was to study the solidification and microstructure of fusion zone when using a pulsed Nd:YAG laser. The laser and optical beam parameters were chosen to achieve a good weld with total penetration. Optical microscopy pictures showed a typical keyhole weld with total penetration, small pores and free of cracks. The x-ray spectrometry by energy dispersion

  12. Cementos con cenizas volantes

    Directory of Open Access Journals (Sweden)

    Ossa M., Mauricio

    1984-03-01

    additions of 20 and 30% .

    Casi la generalidad de los estudios realizados sobre cementos con adición de cenizas volantes se refieren a sus características y comportamiento en pastas, morteros y hormigones, siempre en relación con aquéllos del cemento portland. Esta vez, se desarrolló un trabajo experimental orientado a relacionar entre sí los cementos con adiciones de cenizas volantes y de puzolana natural. Para ello se fabricaron a escala de laboratorio cementos de ambos tipos, empleando como materias primas comunes clinker y yeso y, como variables, diferentes porcentajes de las dos adiciones, que cumplieron previamente los requisitos normalizados en cuanto a sus actividades puzolánicas. La calidad de los cementos fabricados resultó adecuada y concordante con la del cemento portland-puzolánico obtenido a escala industrial con los mismos clinker, yeso y puzolana natural de este estudio. Posteriormente, se determinaron las características de los cementos experimentales y se confeccionaron morteros normales para la realización de ensayos físicos y mecánicos. Los resultados de ensayos indicaron que los cementos con adición de cenizas volantes (CCV requieren menos agua para consistencia normal, presentan tiempos de fraguado mayores y expansiones en autoclave menores que los cementos con adición de puzolana (CP. Los calores de hidratación a 7 y 28 días de edad fueron aproximadamente similares para ambos tipos de cemento. En morteros normales, los cementos CCV mostraron menor retracción de secado, mayor retentividad y mayor fluidez (para igual cantidad de agua que los cementos CP. En los ensayos de exudación se observó que ésta depende más de la finura que el tipo de adición. Finalmente, los ensayos mecánicos señalaron que las resistencias a compresión y flexotracción de los morteros con cementos CCV son menores a edades inferiores que 14 días (del orden de 5 a 10% a un día de edad, pero que a partir de entonces pasan a ser mayores que las de

  13. Influencia del tiempo de nitruración en baño de sales en el comportamiento tribológico de un acero de herramientas AISI H13

    Directory of Open Access Journals (Sweden)

    Castro, G.

    2007-12-01

    Full Text Available Tribological high temperature characteristics of a H13 tool steel treated by salt bath have been studied. AISI H13 steel samples were nitrided by a sursulf bath, varying nitriding time from 1 to 24 h. Optical microscopy and micro-hardness deep profile through the nitrided layer were performed for each nitriding time. Standard pin-on-disk wear tests were conducted at high temperature. Sliding distance was varied from 150 m to 900 m. It has been observed that friction coefficient does not change with nitriding time and wear rate varies as a function of the sliding distance due to the presence of different wear mechanisms. For short sliding distances, the wear mechanisms that contribute to the total wear were plastic deformation and abrasion, whereas for greater sliding distances the mechanisms that control wear behaviour were oxidation and abrasion.

    Se han investigado las características tribológicas a alta temperatura de un acero de herramientas para trabajo en caliente nitrurado en baño de sales sursulf. Se ha variado el tiempo de nitruración desde 1 hasta 24 h, para analizar su influencia en la microestructura obtenida y en el comportamiento frente al desgaste. Se han realizado ensayos de desgaste a alta temperatura y se ha evaluado la ratio de desgaste y el coeficiente de fricción. Se ha observado que el coeficiente de fricción no varía con el tiempo de nitruración y que la ratio de desgaste varía con la distancia de deslizamiento debido a la presencia de distintos mecanismos de desgaste, pero es independiente del tiempo de nitruración. Así, para distancias de ensayo cortas, los mecanismos de desgaste que contribuyen al desgaste total son deformación plástica y abrasión, mientras que para mayores distancias de deslizamiento los mecanismos observados son oxidación y abrasión.

  14. con problemas de aprendizaje

    Directory of Open Access Journals (Sweden)

    Claudia Jaquelina González Trujillo

    2007-01-01

    Full Text Available Un grupo de niños con diversos problemas de aprendizaje fue atendido bajo un programa de intervención de integración y adaptación social. Mejoras importantes se obtienen en competencias académicas bajo el presente programa de intervención y delimitan áreas de oportunidad para la mejora en aspectos cognitivos como el del proceso de atención e integración social. Las implicaciones de los resultados se discuten bajo un programa de apoyo psicopedagógico para la educación especial.

  15. Mayonesa con quitosano

    OpenAIRE

    Gaffrey, María Celeste

    2014-01-01

    Introducción: El quitosano es un polímero natural que se obtiene a partir de la quitina, la cual forma parte de la estructura de soporte de numerosos organismos vivos, tales como artrópodos (crustáceos e insectos), moluscos y hongos. Presenta propiedades aplicables en los alimentos, como estabilizante, emulsificante, y quelante. No puede ser digerido por los seres humanos por lo cual está considerado como una fibra dietética con un contenido calórico cero. Objetivos: Evaluar...

  16. Atender con ansiedad

    Directory of Open Access Journals (Sweden)

    Alberto Acosta

    2009-10-01

    Full Text Available Tener una personalidad ansiosa o estar ansioso en una determinada situación hace que atendamos de modo diferente a lo que acontece. Investigaciones recientes están descubriendo las relaciones específicas de la ansiedad-rasgo y de la ansiedad-estado con diferentes procesos atencionales. La intervención terapéutica para aliviar los trastornos de ansiedad, tan frecuentes en nuestra época, se va a beneficiar de este conocimiento.

  17. Creo con mis dedos

    OpenAIRE

    S??nchez Aniceto, Monta??a

    2015-01-01

    Las artes pl??sticas son muy importantes para los ni??os/as sobre todo para Educaci??n Infantil ya que promueven la creatividad mediante diferentes recursos y t??cnicas lo que favorece su motivaci??n en las competencias desde la edad temprana hasta la adolescencia. Es la primera forma que tiene el ni??o/a de expresarse en el mundo (a trav??s de los garabatos), de comunicarse, compartir sus emociones con los dem??s, creando su propio lenguaje que evolucionar?? hacia el lenguaje oral y escri...

  18. Eugenistas, pero con prudencia

    Directory of Open Access Journals (Sweden)

    Pogliano, Claudio

    1999-12-01

    Full Text Available Thinking that one could not describe eugenics like a unique movement, since numerous bound varians took place related to the geographical and cultural context, this article tries to demostrate the peculiarity of the Italian case. If already in 1889 Giuseppe Sergi wanted that the artificial selection take it to end what should make the natural, avoiding the risk of the so called «degeneration», only in the face of the First World War seems to grow the alarm for the decadent quality of the population, finding a more and more wide echo. In 1919 the Siges was born (Società italiana de genetica ed eugenica shocked under the impression of the difusse fear about the butcher the war had caused. From there from now on fastens a «nazional» direction closely related to the traditional thought and also with the new political temper. A «moderate» direction, Fascist, Catholic, that was built in consonance with the pronatalism of the regime and in rough polemic with the presumed Anglo-Saxon eugenics aberration.

    Partiendo de la base de que no se puede describir la eugénica como un movimiento unitario, ya que se produjeron numerosas variantes ligadas al contexto geográfico y cultural, este artículo intenta demostrar la peculiaridad del caso italiano. Si ya en 1889 Giuseppe Sergi deseaba que la selección artificial llevase a cabo lo que debía de hacer la natural, evitando así el riesgo de la «degeneración », sólo ante la Primera Guerra Mundial parece crecer la alarma por la decadente calidad de la población, encontrando un eco cada vez más amplio. En 1919 nació la Sige (Società italiana de genetica ed eugenica bajo la impresión del difuso temor que la carnicería bélica había provocado. De ahí en adelante prende rápidamente una dirección «nazional» que se imbrica tanto con una tradición del pensamiento como con el nuevo temple político. Una dirección «moderada» fascista, católica, que se construyó en consonancia con el

  19. Arquitectura con discurso

    OpenAIRE

    Schaposnik, Viviana

    2001-01-01

    En particular a la Carrera Arquitectura le compete un doble rol social: uno general, "educar" desde la Universidad y otro, específico, el que le es propio: dar respuesta a las necesidades planteadas por la sociedad haciéndole su lugar: construyéndolo junto con ella. Aparece la figura del "alumno de arquitectura"' nuestro destinatario específico. El alumno de arquitectura, también deberá tomar conciencia, entender, que el "espacio" que él deberá dominar a través d...

  20. Influence of Size on the Microstructure and Mechanical Properties of an AISI 304L Stainless Steel—A Comparison between Bulk and Fibers

    Directory of Open Access Journals (Sweden)

    Francisco J. Baldenebro-Lopez

    2015-01-01

    Full Text Available In this work, the mechanical properties and microstructural features of an AISI 304L stainless steel in two presentations, bulk and fibers, were systematically studied in order to establish the relationship among microstructure, mechanical properties, manufacturing process and effect on sample size. The microstructure was analyzed by XRD, SEM and TEM techniques. The strength, Young’s modulus and elongation of the samples were determined by tensile tests, while the hardness was measured by Vickers microhardness and nanoindentation tests. The materials have been observed to possess different mechanical and microstructural properties, which are compared and discussed.

  1. Fatigue life and cyclic deformation behaviour of quenched and tempered steel AISI 4140 at two-step stress- and total-strain-controlled push-pull loading

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, V.; Lang, K.H.; Macherauch, E. [Inst. fuer Werkstoffkunde I, Univ. Karlsruhe (Germany)

    2003-05-01

    The behaviour of steels at multi-step cyclic loading was explored up to now almost exclusively in fatigue-life-oriented investigations. Thus, only few works exist dealing with the cyclic deformation behaviour at two- and multi-step loading. Therefore, the cyclic deformation behaviour at two-step experiments with a single amplitude change (2-block experiments) and with multiple changes between two blocks of certain length and different amplitudes (multi-block experiments) was investigated in this work at the technically important steel AISI 4140 (German grade 42CrMo4). (orig.)

  2. Estudio de la influencia microbiológica en la corrosión de latones (UNS C68700, UNS C443 y acero inoxidable AISI 316;

    Directory of Open Access Journals (Sweden)

    Ohanian, Mauricio

    2014-06-01

    Full Text Available Microorganisms may play an important role in the corrosion process and generate conditions which affect the rate and/or the mechanism of deterioration. They become visible by the formation of biofilms: clusters of microorganisms and extracellular polymers. These biofilms affect not only the durability of the material, but also reduce the heat transfer. The present work studied the growth of aerobic and anaerobic heterotrophic microorganisms and sulfate reducing bacteria on aluminum brass (UNS C68700, admiralty brass (UNS C443 and stainless steel AISI 316 in exposure experiments held in the Bay of Montevideo (Uruguay. The influence of the biofilm growth on the corrosion behavior was studied by electrochemical techniques: polarization curves and Electrochemical Impedance Spectroscopy (EIS. The selection of the most suitable material for the exposure conditions is discussed and hypotheses of the corrosion mechanism are presented. Although stainless steel AISI 316 presented the lowest corrosion rate it showed localized deterioration.Los microorganismos influyen de manera significativa en el proceso corrosivo y generan condiciones que afectan la velocidad y/o el mecanismo de deterioro. Su presencia se manifiesta por la formación de bio-películas: conglomerados de bacterias y polímeros extracelulares. Dichas bio-películas afectan la durabilidad del material, la velocidad de flujo y la transferencia de calor. En el presente trabajo se evalúa el crecimiento de microorganismos heterótrofos aerobios, heterótrofos anaerobios y bacterias sulfato-reductoras sobre latón aluminio (UNS C68700, latón almirantazgo (UNS C443 y acero inoxidable AISI 316. Asimismo, se estudia la influencia del crecimiento de la bio-película sobre el comportamiento corrosivo mediante técnicas electroquímicas: curvas de polarización y espectroscopia de impedancia electroquímica. Las exposiciones se realizan en la Bahía de Montevideo, estuario del Río de la Plata

  3. Experimental investigation and modelling of surface roughness and resultant cutting force in hard turning of AISI H13 Steel

    Science.gov (United States)

    Boy, M.; Yaşar, N.; Çiftçi, İ.

    2016-11-01

    In recent years, turning of hardened steels has replaced grinding for finishing operations. This process is compared to grinding operations; hard turning has higher material removal rates, the possibility of greater process flexibility, lower equipment costs, and shorter setup time. CBN or ceramic cutting tools are widely used hard part machining. For successful application of hard turning, selection of suitable cutting parameters for a given cutting tool is an important step. For this purpose, an experimental investigation was conducted to determine the effects of cutting tool edge geometry, feed rate and cutting speed on surface roughness and resultant cutting force in hard turning of AISI H13 steel with ceramic cutting tools. Machining experiments were conducted in a CNC lathe based on Taguchi experimental design (L16) in different levels of cutting parameters. In the experiments, a Kistler 9257 B, three cutting force components (Fc, Ff and Fr) piezoelectric dynamometer was used to measure cutting forces. Surface roughness measurements were performed by using a Mahrsurf PS1 device. For statistical analysis, analysis of variance has been performed and mathematical model have been developed for surface roughness and resultant cutting forces. The analysis of variance results showed that the cutting edge geometry, cutting speed and feed rate were the most significant factors on resultant cutting force while the cutting edge geometry and feed rate were the most significant factor for the surface roughness. The regression analysis was applied to predict the outcomes of the experiment. The predicted values and measured values were very close to each other. Afterwards a confirmation tests were performed to make a comparison between the predicted results and the measured results. According to the confirmation test results, measured values are within the 95% confidence interval.

  4. AISI/DOE Technology Roadmap Program: A Technology of Low Coal Rate and High Productivity of RHF Ironmaking

    Energy Technology Data Exchange (ETDEWEB)

    Wei-Kao Lu

    2002-09-15

    An economical and environment-friendly ironmaking process based on heating the chemiexecy self-sufficient green balls of iron ore and coal in a hearth furnace is being developed with financial support from AISI members and DOE. DRI, which is hot (1400 C), dense (3.2 g/cm) and of high degree of metallization (95%), has been produced in laboratory and in a pilot plant in Genoa, Italy. Products of such quality have been made from American and Brazilian ores, BOF sludge, EAF dust/BOF sludge mixtures and millscale. The removal of zinc and lead from green balls by this process is essentially complete. In comparison with typical blast furnace operation, the new technology with a melter would have a lower total coal rate by 200kg.THM. The elimination of cokemaking and high temperature agglomeration steps, and a simpler gas handling system would lead to lower capital and operating costs. In comparison with commercial RHF practice it is different in atmosphere (fully oxidized at 1600 to 1650 C), in bed height (120 mm instead of 20-25 mm) and in pellet composition (much less coal but of higher VM). The combined effect leads to three times higher furnace productivity, lower coal consumption and superior DRI quality. The risk of re-oxidation (slag formation) and dusty operation are practiexecy eliminated. The process is stable, tolerant and independent of the size, shape and movement of the hearth. However, materials handling (e.g., discharge of hot DRI) and the exact energy savings have to be established in a larger furnace, straight or rotary, and in a continuous mode of operation.

  5. Optimization of Minimum Quantity Lubricant Conditions and Cutting Parameters in Hard Milling of AISI H13 Steel

    Directory of Open Access Journals (Sweden)

    The-Vinh Do

    2016-03-01

    Full Text Available As a successful solution applied to hard machining, the minimum quantity lubricant (MQL has already been established as an alternative to flood coolant processing. The optimization of MQL parameters and cutting parameters under MQL condition are essential and pressing. The study was divided into two parts. In the first part of this study, the Taguchi method was applied to find the optimal values of MQL condition in the hard milling of AISI H13 with consideration of reduced surface roughness. The L9 orthogonal array, the signal-to-noise (S/N ratio and analysis of variance (ANOVA were employed to analyze the effect of the performance characteristics of MQL parameters (i.e., cutting fluid type, pressure, and fluid flow on good surface finish. In the results section, lubricant and pressure of MQL condition are determined to be the most influential factors which give a statistically significant effect on machined surfaces. A verifiable experiment was conducted to demonstrate the reliability of the results. In the second section, the optimized MQL parameters were applied in a series of experiments to find out cutting parameters of hard milling. The Taguchi method was also used to optimize the cutting parameters in order to obtain the best surface roughness. The design of the experiment (DOE was implemented by using the L27 orthogonal array. Based on an analysis of the signal-to-noise response and ANOVA, the optimal values of cutting parameters (i.e., cutting speed, feed rate, depth-of-cut and hardness of workpiece were introduced. The results of the present work indicate feed rate is the factor having the most effect on surface roughness.

  6. Entrevista con Geoffrey Lloyd.

    Directory of Open Access Journals (Sweden)

    Fernando Colina Pérez

    2008-01-01

    Full Text Available Helenista y también sinólogo de relieve internacional, Geoffrey E. R. Lloyd nació en Londres (1933, de padres galeses. Es un gran historiador de la ciencia y del pensamiento griegos. En 1940 fue evacuado de Londres con su madre. Sus estudios significativos comenzaron, tras algún rodeo, en el King’s College donde estudiaba su hermano. Éste sería, como su padre, médico, y él mismo dudó en estudiar esa profesión, que late en sus libros. Pero un profesor de clásicas como John Raven –que redactó, con Geoffrey Kirk, Los filósofos presocráticos–, le indujo a ocuparse de la filosofía antigua; y otro maestro, William Guthrie –a quien debemos la gran Historia de la filosofía griega–, le inició, además, en la medicina griega.

  7. con la cosecha mecanizada

    Directory of Open Access Journals (Sweden)

    Arturo Martínez Rodríguez

    2006-01-01

    Full Text Available Las investigaciones dirigidas a incrementar los indicadores de eficiencia y calidad durante la cosecha mecanizada del café, constituyen un tema de gran actualidad a nivel internacional. La determinación de las propiedades físico-mecánicas de los frutos y del sistema frutopedúnculo, es una etapa indispensable durante las investigaciones relacionadas con la cosecha mecanizada de este producto. En este trabajo se brindan los resultados sobre la determinación de un grupo de propiedades dimensionales, inerciales y elásticas del sistema fruto-pedúnculo de coffea arabica variedad Catuai en diferentes estadios de maduración, relacionadas con la cosecha mecanizada de este cultivo.Así mismo se determina el momento flector requerido para la ruptura de la unión fruto pedúnculo. Durante la investigación se emplearon técnicas de procesamiento de imágenes digitales, así como de extensometría eléctrica. Como resultado de la medición de las diferentes propiedades se apreciaron diferencias sustanciales en las características dimensionales, inerciales y elásticas de los frutos maduros y verdes, así como en el momento requerido para el desprendimiento de los frutos y en las formas en que se produce el desprendimiento.

  8. Entrevista con Patricia Ariza

    Directory of Open Access Journals (Sweden)

    Esperanza Londoño La Rotta

    2017-01-01

    Full Text Available Pensamiento, Palabra y Obra entrevista a una artista, feminista y activista política, quien como mujer y artista ha permitido pensar el arte más allá de un simple espectáculo. Toda una vida dedicada al teatro y a darle voz, a través de sus obras, a víctimas del conflicto colombiano, defensora de derechos humanos; además de hacer evidente en su vida y a través de la plataforma “Artistas por la paz”, las múltiples relaciones que se pueden establecer entre el arte, la construcción de paz y la resolución de conflictos. Hablamos en su casa, en medio del calor de la bienvenida con Patricia Ariza, directora del festival alternativo de teatro, de Mujeres en Escena y de la Corporación Colombiana de Teatro, entre otras muchas actividades que voluntariamente su espíritu libertario ha asumido. Esta entrevista se realizó antes del 2 de octubre, pero con la revisión de los acuerdos que propició el plebiscito ganado por una ínfima minoría por el no, sigue siendo vigente este planteamiento.

  9. Efecto de la velocidad y ángulo de impacto en la resistencia a corrosión - erosión de aceros inoxidables recubiertos con TiN

    Directory of Open Access Journals (Sweden)

    José Ricardo Cano Rodas

    2004-01-01

    Full Text Available Fueron estudiados los mecanismos de degradación superficial en aceros inoxidables austenítico AISI 304 y martensítico AISI 420, con y sin recubrimiento cerámico de TiN, aplicado mediante técnica de deposición física de vapor PVD por arco pulsado, sometidos a erosión (solución de agua destilada con 30% en peso de partículas de sílice, corrosión (solución ½ M H2SO4 + 3.5% NaCl y efectos sinérgicos corrosión - erosión. Fue construido un dispositivo para realizar los ensayos descritos con la posibilidad de variar la velocidad y el ángulo medio de impacto de las partículas sobre la superficie de las muestras. Marcas características fueron observadas en las superficies desgastadas, siendo la condición de ángulo rasante la de mayor efecto nocivo tanto para las superficies desnudas como para las recubiertas con TiN. El nivel de deterioro superficial aumentó con la velocidad de impacto, al tiempo que se evidenció la importancia de la adherencia de las películas protectoras al substrato para la obtención de una buena resistencia a corrosiónerosión. La sinergia corrosión-erosión presentó, en algunas ocasiones, un efecto positivo para la superficie, ya que el impacto de las partículas duras causó intensa deformación plástica pero no consiguió remover material de la superficie.

  10. Entrevista con Juan Marichal.

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    - Consejo de Redacción

    1997-01-01

    Full Text Available Juan Marichal nació en Santa Cruz de Tenerife, en 1922, en el seno de una familia ligada al partido republicano insular. Muy joven, en 1935, se trasladó a Madrid, ciudad en la que vive el estallido de la guerra civil. En 1937, pasa a Valencia y luego a Barcelona; tras su exilio en 1938, prosigue sus estudios secundarios en un liceo de París, concluyéndolos en Casablanca. En 1941 emigra a México, formándose en la UNAM: fue alumno de los exiliados José Gaos y Joaquín Xirau así como del mexicano Edmundo O 'Gorman. Luego, becado en Princeton desde 1946, lo fue de América Castro, donde preparó una tesis sobre Feijoo. Apoyado en las vastas perspectivas de sus maestros, fue orientándose hada nuestra historia intelectual, desde el siglo XV hasta hoy. Su carrera profesional se ha desarrollado en los Estados Unidos (coincidiendo con Amado Alonso y con Ferrater Mora: ha sido profesor de estudios hispánicos en la Universidad de Harvard, desde 1948 hasta 1988, año en que se jubiló voluntariamente como numerario (aunque había permanecido en el Bryn Mawr College, entre 1953 y 1957. A este trabajo se suman, con todo, sus conferencias en América Latina y en España. Ha colaborado en las revistas más importantes, en este campo, de México, Nueva York, Puerto Rico, La Habana, Buenos Aires o París así como de las españolas, desde los sesenta. Juan Marichal -hoy, miembro de la Junta Directiva de los Amigos de la Residencia de Estudiantes, director del Boletín de la Institución Libre de Enseñanza y asociado al Instituto Universitario Ortega y Gasset-, reside en España desde otoño de 1989: se considera a sí mismo «voluntario en Madrid», como había dicho Alfonso Reyes en su estancia madrileña (1914-1924.

  11. Musicalizarte con las Tics

    OpenAIRE

    Gamarra, Patricia Mabel; Velázquez, Helvecia Mercedes del Rocío; Verón, José María

    2015-01-01

    El presente trabajo hace referencia a un relato de experiencia didáctica desarrollada en el Instituto Superior de Música “Prof. Carmelo H. de Biasi” de Corrientes- Argentina, donde el área de interés de Tecnología en Educación se dirige hacia “Aplicación de las TIC en Educación/ Experiencias concretas de utilización de TIC en Educación”. En el diagnóstico realizado en la institución, se pudo observar la escasa transversalidad e interrelación con las distintas áreas curriculares como ser: l...

  12. Mirando con la cabeza

    OpenAIRE

    Corrales, Capi

    2006-01-01

    Las matemáticas y la pintura trabajan con ideas. La palabra idea viene del griego ειδω, que significa ver, mirar u observar, y de ειδοζ, que significa figura, forma, aspecto o visión. Detrás de una montaña concreta está la idea de montaña, un dibujo abstracto, unas líneas que permiten reconocer la montaña detrás de las rocas, los pinos o la nieve. La diferencia entre este árbol y árbol, entre un círculo que dibujamos en la pizarra y círculo: la diferencia entre la cosa y la idea de la cosa. E...

  13. Entrevista con Georges Duby.

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    - Consejo de Redacción

    1994-01-01

    Full Text Available Duby, heredero de dos grandes historiadores como Marc Bloch y Lucien Febvre, es uno de los más importantes medievalistas europeos. Fue, y sigue siendo, un motor de la importante reforma en la historia producida desde los sesenta. En sus primeros trabajos se acusa la recepción de las ideas económicas y geográficas de la mejor historiografía. Su riguroso estudio sobre la base material de la Edad Media, le permitirá luego irrumpir en la historia de las mentalidades, analizando, como decía Febvre, el utillaje mental (vocabulario, sintaxis, lugares comunes, cuadros lógicos, etc. del Medioevo. Así, el ejemplo de Mauss y LéviStrauss le anima a trabajar sobre el matrimonio, la sexualidad y ciertos sistemas del pensamiento: el primero, con su defensa de los hechos sociales totales, y el segundo, que buscaba las dimensiones simbólicas de lo social, le impulsan a trabajar sobre la ideología entendida no como mero reflejo de la situación material sino como «proyecto de acción sobre lo vivido». A su obra individual, atenta a los impulsos culturales más vivos, se suma su empuje decisivo en la realización de proyectos colectivos como la Historia de la vida privada o la Historia de las mujeres. Prácticamente, han sido traducidos todos sus libros al castellano, y han podido verse en España asimismo varios de sus programas televisivos (ha sido presidente de la SEPT, cadena de televisión cultural fundada en 1985. La amplitud de sus intereses intelectuales, transmitidos en su obra con un lenguaje a la vez muy claro y bellamente elaborado, se hace palpable también en este diálogo.

  14. Effect of Continuous and Pulsed Current Gas Tungsten Arc Welding on Dissimilar Weldments Between Hastelloy C-276/AISI 321 Austenitic Stainless Steel

    Science.gov (United States)

    Sharma, Sumitra; Taiwade, Ravindra V.; Vashishtha, Himanshu

    2017-02-01

    In the present investigation, an attempt has been made to join Hastelloy C-276 nickel-based superalloy and AISI 321 austenitic stainless steel using ERNiCrMo-4 filler. The joints were fabricated by continuous and pulsed current gas tungsten arc welding processes. Experimental studies to ascertain the structure-property co-relationship with or without pulsed current mode were carried out using an optical microscope and scanning electron microscope. Further, the energy-dispersive spectroscope was used to evaluate the extent of microsegregation. The microstructure of fusion zone was obtained as finer cellular dendritic structure for pulsed current mode, whereas columnar structure was formed with small amount of cellular structure for continuous current mode. The scanning electron microscope examination witnessed the existence of migrated grain boundaries at the weld interfaces. Moreover, the presence of secondary phases such as P and μ was observed in continuous current weld joints, whereas they were absent in pulsed current weld joints, which needs to be further characterized. Moreover, pulsed current joints resulted in narrower weld bead, refined morphology, reduced elemental segregation and improved strength of the welded joints. The outcomes of the present investigation would help in obtaining good quality dissimilar joints for industrial applications and AISI 321 ASS being cheaper consequently led to cost-effective design also.

  15. Corrosion Performance of AISI-309 Exposed to Molten Salts V2O5-Na2SO4 at 700°C Applying EIS and Rp Electrochemical Techniques

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    E. F. Diaz

    2015-01-01

    Full Text Available The corrosion performance of AISI-309 exposed 5 days to molten salts 50 mol% V2O5-50 mol% Na2SO4 at 700°C is reported in this paper. Such evaluation was made using three electrochemical techniques: potentiodynamic polarization curve (PC, electrochemical impedance spectroscopy (EIS, and linear polarization resistance (Rp. From PC, the Tafel slopes, Icorr, and Ecorr were obtained. From Nyquist and Bode plots, it was possible to determine two different stages; the first one showed just one loop, which indicated the initial formation of Cr2O3 layer over the metallic surface; after that, the dissolution of Cr2O3 formed a porous layer, which became part of the corrosion products; at the same time a NiO layer combined with sulfur was forming, which was suggested as the second stage, represented by two capacitive loops. EIS plots were in agreement with the physical characterization made from SEM and EDS analyses. Fitting of EIS experimental data allowed us to propose two electrical circuits, being in concordance with the corrosion stages. Parameters obtained from the simulation of EIS data are also reported. From the results, it was stated that AISI-309 suffered intergranular corrosion due to the presence of sulfur, which diffused to the metallic surface through a porous Cr2O3 layer.

  16. Microstructure, Strength, and Fracture Topography Relations in AISI 316L Stainless Steel, as Seen through a Fractal Approach and the Hall-Petch Law

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    Oswaldo Antonio Hilders

    2015-01-01

    Full Text Available The influence of the fracture surface fractal dimension DF and the fractal dimension of grain microstructure DM on the strength of AISI 316L type austenitic stainless steel through the Hall-Petch relation has been studied. The change in complexity experimented by the net of grains, as measured by DM, is translated into the respective fracture surface irregularity through DF, in such a way that the higher the grain size (lower DM values the lower the fracture surface roughness (lower values of DF and the shallower the dimples on the fractured surfaces. The material was heat-treated at 904, 1010, 1095, and 1194°C, in order to develop equiaxed grain microstructures and then fractured by tension at room temperature. The fracture surfaces were analyzed with a scanning electron microscope, DF was determined using the slit-island method, and the values of DM were taken from the literature. The relation between grain size, DM, mechanical properties, and DF, developed for AISI 316L steel, could be generalized and therefore applied to most of the common micrograined metal alloys currently used in many key engineering areas.

  17. Multi performance characteristic optimization of shot peening process for AISI 304 austenitic stainless steel using grey relational analysis with principal component analysis and Taguchi method

    Directory of Open Access Journals (Sweden)

    Dr. Lakhwinder Singh

    2013-10-01

    Full Text Available Shot peening is a cold working process. It impact on thin surface layer of the material and is used to enhance the mechanical and surface properties. The manufacturer is in demand to reduce the cost and improve the process productivity. He is always in search of an optimization technique which involves multiple performance characteristics. From this work, an optimal combination of shot peening parameters is generated by using a Grey relational analysis (GRA with Principal component analysis (PCA and Taguchi method. The present study shows that there are many factors that affect the properties of the AISI 304 austenitic stainless steel. Mechanisms to compensate for surface tractions and further enhancement of mechanical properties are described. The shot peening is discussed to enhance the mechanical and surface properties of AISI 304 austenitic stainless steel. The optimization of shot pening process is done by including multi performance characteristics i.e. tensile strength, surface hardness an fatigue strengths. The analysis includes pressure, shot size, exposure time, nozzle distance and nozzle angle as process parameters. The complete analysis will be helpful to the manufacturer in deciding the shot peening parameters for required performance characteristics.

  18. Formation of Biofilms and Biocorrosion on AISI-1020 Carbon Steel Exposed to Aqueous Systems Containing Different Concentrations of a Diesel/Biodiesel Mixture

    Directory of Open Access Journals (Sweden)

    Ivanilda Ramos de Melo

    2011-01-01

    Full Text Available Environmental and economic concerns accelerated biofuels research and industrial production. Many countries have been using diesel and biodiesel blends as fuels justifying research on biofilms formation and metals corrosion. Cylinders made of AISI-1020 carbon steel with an exposed area of 1587 mm2, water, and water associated with B3 fuel (diesel/biodiesel blend at 97 : 3 v/v were used.The formation of biofilms was detected, and biocorrosion was detected on AISI-1020. The results showed a variation in sessile microflora during the experiments. In the biofilms, a significant concentration of aerobic, anaerobic, IOB, Pseudomonas aeruginosa, and sulfate-reducing bacteria was observed. The corrosion rates varied between 0.45±0.01 and 0.12±0.01 mm/year, depending on the experimental conditions. The main corrosion products identified were various forms of FeOOH, magnetite, and all forms of FexSy. In systems where there were high levels of sulfate reducing bacteria, corrosion pits were observed. In addition, the aliphatic hydrocarbons present in the fluid containing 10% B3 were totally degraded.

  19. Effect of Continuous and Pulsed Current Gas Tungsten Arc Welding on Dissimilar Weldments Between Hastelloy C-276/AISI 321 Austenitic Stainless Steel

    Science.gov (United States)

    Sharma, Sumitra; Taiwade, Ravindra V.; Vashishtha, Himanshu

    2017-03-01

    In the present investigation, an attempt has been made to join Hastelloy C-276 nickel-based superalloy and AISI 321 austenitic stainless steel using ERNiCrMo-4 filler. The joints were fabricated by continuous and pulsed current gas tungsten arc welding processes. Experimental studies to ascertain the structure-property co-relationship with or without pulsed current mode were carried out using an optical microscope and scanning electron microscope. Further, the energy-dispersive spectroscope was used to evaluate the extent of microsegregation. The microstructure of fusion zone was obtained as finer cellular dendritic structure for pulsed current mode, whereas columnar structure was formed with small amount of cellular structure for continuous current mode. The scanning electron microscope examination witnessed the existence of migrated grain boundaries at the weld interfaces. Moreover, the presence of secondary phases such as P and μ was observed in continuous current weld joints, whereas they were absent in pulsed current weld joints, which needs to be further characterized. Moreover, pulsed current joints resulted in narrower weld bead, refined morphology, reduced elemental segregation and improved strength of the welded joints. The outcomes of the present investigation would help in obtaining good quality dissimilar joints for industrial applications and AISI 321 ASS being cheaper consequently led to cost-effective design also.

  20. Effects of Deep Cryogenic Treatment on the Wear Resistance and Mechanical Properties of AISI H13 Hot-Work Tool Steel

    Science.gov (United States)

    Çiçek, Adem; Kara, Fuat; Kıvak, Turgay; Ekici, Ergün; Uygur, İlyas

    2015-11-01

    In this study, a number of wear and tensile tests were performed to elucidate the effects of deep cryogenic treatment on the wear behavior and mechanical properties (hardness and tensile strength) of AISI H13 tool steel. In accordance with this purpose, three different heat treatments (conventional heat treatment (CHT), deep cryogenic treatment (DCT), and deep cryogenic treatment and tempering (DCTT)) were applied to tool steel samples. DCT and DCTT samples were held in nitrogen gas at -145 °C for 24 h. Wear tests were conducted on a dry pin-on-disk device using two loads of 60 and 80 N, two sliding velocities of 0.8 and 1 m/s, and a wear distance of 1000 m. All test results showed that DCT improved the adhesive wear resistance and mechanical properties of AISI H13 steel. The formation of small-sized and uniformly distributed carbide particles and the transformation of retained austenite to martensite played an important role in the improvements in the wear resistance and mechanical properties. After cleavage fracture, the surfaces of all samples were characterized by the cracking of primary carbides, while the DCT and DCTT samples displayed microvoid formation by decohesion of the fine carbides precipitated during the cryo-tempering process.

  1. Cultures and co-cultures of human blood mononuclear cells and endothelial cells for the biocompatibility assessment of surface modified AISI 316L austenitic stainless steel.

    Science.gov (United States)

    Stio, Maria; Martinesi, Maria; Treves, Cristina; Borgioli, Francesca

    2016-12-01

    Samples of AISI 316L austenitic stainless steel were subjected either to grinding and polishing procedure, or to grinding and then low temperature glow-discharge nitriding treatment, or to grinding, nitriding and subsequently coating with collagen-I. Nitrided samples, even if only ground, show a higher corrosion resistance in PBS solution, in comparison with ground and polished AISI 316L. Biocompatibility was evaluated in vitro by incubating the samples with either peripheral blood mononuclear cells (PBMC) or human umbilical vein endothelial cells (HUVEC), tested separately or in co-culture. HUVEC-PBMC co-culture and co-incubation of HUVEC with PBMC culture medium, after the previous incubation of PBMC with metallic samples, allowed to determine whether the incubation of PBMC with the different samples might affect HUVEC behaviour. Many biological parameters were considered: cell proliferation, release of cytokines, matrix metalloproteinases (MMPs) and sICAM-1, gelatinolytic activity of MMPs, and ICAM-1 protein expression. Nitriding treatment, with or without collagen coating of the samples, is able to ameliorate some of the biological parameters taken into account. The obtained results point out that biocompatibility may be successfully tested in vitro, using cultures of normal human cells, as blood and endothelial cells, but more than one cell line should be used, separately or in co-culture, and different parameters should be determined, in particular those correlated with inflammatory phenomena.

  2. Effective Duration of Gas Nitriding Process on AISI 316L for the Formation of a Desired Thickness of Surface Nitrided Layer

    Directory of Open Access Journals (Sweden)

    Mahmoud Hassan R. S.

    2014-07-01

    Full Text Available High temperature gas nitriding performed on AISI 316L at the temperature of 1200°C. The microstructure of treated AISI 316L samples were observed to identify the formation of the microstructure of nitrided surface layer. The grain size of austenite tends to be enlarged when the nitriding time increases, but the austenite single phase structure is maintained even after the long-time solution nitriding. Using microhardness testing, the hardness values drop to the center of the samples. The increase in surface hardness is due to the high nitrogen concentration at or near the surface. At 245HV, the graph of the effective duration of nitriding process was plotted to achieve the maximum depth of nitrogen diffuse under the surface. Using Sigma Plot software best fit lines of the experimental result found and plotted to find out effective duration of nitriding equation as Y=1.9491(1-0.7947x, where Y is the thickness of nitrided layer below the surface and X is duration of nitriding process. Based on this equation, the duration of gas nitriding process can be estimated to produce desired thickness of nitrided layer.

  3. Comportamiento de las aleaciones termorresistentes AISI HH y HK-40 ante los procesos de carburización y nitruración

    Directory of Open Access Journals (Sweden)

    Eleno Alfonso-Brindis

    2001-03-01

    Full Text Available Se evalúa el comportamiento de los aceros austeníticos fundidos AISI HH y HK- 40 (de producción nacional ante los procesos de carburización y nitruración en los rangos de temperaturas desde 750 hasta 1 000 °C. Se estudia la cinética y la termodinámica de las posibles reacciones y los productos de las mismas se caracterizan mediante técnicas de Microscopía Óptica, Microscopía Electrónica de Barrido y Microanálisis (MEB-EDAX. En el análisis microscópico se observó la formación de carburos de cromo después de la carburización, mientras que la nitruración dio lugar a la formación de nitruros de cromo. Se concluye que la aleación AISI HK-40 posee una elevada resistencia intrínseca a la carburización y a la nitruración, que hace factible su empleo en componentes de hornos de soleras múltiples para la reducción de minerales lateríticos

  4. The Role of Diffusion Media in Nitriding Process on Surface Layers Characteristics of AISI 4140 with and without Hard Chrome Coatings

    Directory of Open Access Journals (Sweden)

    K.A. Widi

    2016-09-01

    Full Text Available The surface layer characteristics of the AISI 4140 tool steel treated by nitriding gas before and after hard chrome plating utilizing pure nitrogen diffusion media (fluidized bed reactor and the without gas (muffle reactor has been studied experimentally. The result shows that nitriding substrate with hard chrome layers has nitrogen atoms concentration almost twice greater than that without hard chrome layers. After being given a hard chrome plating, nitriding on AISI 4140 steel generally has a nitrogen concentration of up to 4 times more than the substrate without hard chrome coating. Almost the entire specimen showed the highest concentration of N atoms in the area below the surface (hardening depth of 200 to 450 µm. N atoms diffusion depth profile has a correlation with hardening depth profile, especially on the specimens layered with hard chromium. The substrate without hard chrome plating tends to have higher surface hardness than the sub-surface. The results show that the effectiveness and efficiency of the gas nitriding diffusion process can be produced without the use of gas in the muffle reactor but the specimens must be hard chromium coated first. This phenomenon can be explained by the role of the passive layer formation that works as a barrier to keeps the spreading of N atoms concentrated in sub-surface areas.

  5. preescolares desnutridos con madres con obesidad y sin obesidad

    Directory of Open Access Journals (Sweden)

    Viridiana Vanessa Conzuelo-González

    2009-01-01

    Full Text Available El primer objetivo fue conocer cuántos menores de cinco años con diferentes grados de desnutrición tienen una madre con sobrepeso/obesidad/ en una comunidad indígena que vive en extrema pobreza y bajo condiciones de migración masculina internacional. El segundo fue comparar tres variables socionutricionales (ingreso familiar, educación de la madre y adecuación nutrimental de la dieta diaria entre estos hogares y los hogares con desnutrición infantil y madres sin obesidad. Se realizó un estudio transversal (2006-2007, en la comunidad mazahua de San Francisco Tepeolulco, Municipio de Temascalcingo; que incluyó a 85 hogares integrados por preescolares con desnutrición inscritos al programa Oportunidades. Se determinó el estado nutrición de los preescolares con indicadores antropométricos y se obtuvo el IMC de las madres de estos infantes. Se aplicó una encuesta socionutricional, incluida el recordatorio de 24 horas, y complementado con la observación participante (cualitativa. Se encontró que 83% de las madres mazahuas presentaron sobrepeso u obesidad. El estado de nutrición de los preescolares con madres con obesidad presentó un porcentaje mayor de desnutrición (76%. En la variable género, se encontró que 54% de los niños con madres con obesidad tenía baja talla. Al relacionar el nivel educativo de la madre, esta variable resultó ser estadísticamente significativa (p=0.015, donde el analfabetismo está más relacionado con la desnutrición infantil que tienen madres de bajo y/o peso normal. La elevada prevalencia de hogares conformados con preescolares con desnutrición y madres con obesidad, es un síntoma más de la pobreza en zonas indígenas en México, con bajo índice de desarrollo humano.

  6. Vigas preesforzadas con refuerzo externo

    Directory of Open Access Journals (Sweden)

    Juan José Ferrer Narvaez

    2011-01-01

    Full Text Available Es de gran interés para la ingeniería colombiana el efecto del refuerzo externo de elementos estructurales con elementos metálicos. La Unidad de Estructuras ha venido realizando en el transcurso de esta década estudios en elementos en concreto con refuerzos externos a flexión con resultados satisfactorios. El proyecto ''Vigas preesforzadas con refuerzo externo" sirve de base en el estudio del comportamiento de este tipo de elementos estructurales y la extrapolación de los resultados obtenidos en elementos de concreto reforzado a concreto preesforzado.

  7. Improving the corrosion wear resistance of AISI 316L stainless steel by particulate reinforced Ni matrix composite alloying layer

    Energy Technology Data Exchange (ETDEWEB)

    Xu Jiang; Zhuo Chengzhi; Tao Jie; Liu Linlin [Department of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, 29 Yudao Street, Nanjing 210016 (China); Jiang Shuyun [Department of Mechanical Engineering, Southeast University, 2 Sipailou, Nanjing 210096 (China)], E-mail: xujiang73@nuaa.edu.cn

    2009-01-07

    In order to overcome the problem of corrosion wear of AISI 316L stainless steel (SS), two kinds of composite alloying layers were prepared by a duplex treatment, consisting of Ni/nano-SiC and Ni/nano-SiO{sub 2} predeposited by brush plating, respectively, and subsequent surface alloying with Ni-Cr-Mo-Cu by a double glow process. The microstructure of the two kinds of nanoparticle reinforced Ni-based composite alloying layers was investigated by means of SEM and TEM. The electrochemical corrosion behaviour of composite alloying layers compared with the Ni-based alloying layer and 316L SS under different conditions was characterized by potentiodynamic polarization test and electrochemical impedance spectroscopy. Results showed that under alloying temperature (1000 deg. C) conditions, amorphous nano-SiO{sub 2} particles still retained the amorphous structure, whereas nano-SiC particles were decomposed and Ni, Cr reacted with SiC to form Cr{sub 6.5}Ni{sub 2.5}Si and Cr{sub 23}C{sub 6}. In static acidic solution, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is lower than that of the Ni-based alloying layer. However, the corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiO{sub 2} particles interlayer is prominently superior to that of the Ni-based alloying layer under acidic flow medium condition and acidic slurry flow condition. The corrosion resistance of the composite alloying layer with the brush plating Ni/nano-SiC particles interlayer is evidently lower than that of the Ni-based alloying layer, but higher than that of 316L SS under all test conditions. The results show that the highly dispersive nano-SiO{sub 2} particles are helpful in improving the corrosion wear resistance of the Ni-based alloying layer, whereas carbides and silicide phase are deleterious to that of the Ni-based alloying layer due to the fact that the preferential removal of the matrix

  8. Entrevista con Giovanni Levi.

    Directory of Open Access Journals (Sweden)

    - Consejo de Redacción

    1999-01-01

    Full Text Available Nacido en Milán en 1939, Giovanni Levi, el importante y original historiador italiano, es heredero de una tradición familiar de grandes defensores de la libertad tanto cultural como política. En su práctica investigadora late siempre, de hecho, la memoria de un momento tan crítico de la historia italiana como el final del fascismo. Por añadidura, sus antepasados son judíos del Piamonte. Esta experiencia vital y las luchas sociales de los sesenta han marcado su quehacer como historiador y como estudioso. Levi, reconocido en Italia y asimismo en Europa y América, fue profesor en la Universidad de Turín y luego en la de Viterbo; actualmente es catedrático de Historia económica en Venecia, ejerciendo como profesor visitante en Francia. Su trabajo, muy creativo, aborda aspectos de la historia de la familia, la demografía y la agricultura en los siglos XVII y XVIII, pero su crítica como intelectual comprometido con el dudoso presente desborda su estricto ámbito de estudio.

  9. Entrevista con Alberto Tenenti.

    Directory of Open Access Journals (Sweden)

    - Consejo de Redacción

    1995-01-01

    Full Text Available Gran especialista en historia moderna, Alberto Tenenti nació en Viareggio, en 1924. Tras realizar estudios superiores en Italia, trabajó en el Centre National de la Recherche Scientifique varios años, asesorado por Lucien Febvre. Ha dirigido el Archivo del Estado de Brescia; y, más tarde, ha enseñado en París, desde una cátedra en la École Pratique des Hautes Études en Sciences Sociales (VI Sección, alIado de Braudel. Su Il senso della morte e l'amore della vita nel Rinascimento, de 1957, es una obra maestra sobre los orígenes de la sensibilidad moderna: sin olvidar el naciente vitalismo, estudia el desarrollo de dos motivos, el del ars moriendi, que tiene su evolución propia desde 1350 hasta su difusión impresa, y el de lo macabro, que refleja la crisis de conciencia del siglo XV y adquiere «unas dimensiones desconocidas y verdaderamente anormales». En este libro sobre un problema clave como la muerte, apela de modo notable a la iconografía: Tenenti ha recordado que la cultura tradicional, eclesiástica sobre todo, percibió un mayor peligro en la capacidad de reflexión autónoma y de crítica de los hombres de letras, que en las renovaciones radicales de los artistas. Numerosos trabajos de conjunto realizados por él han perseguido una historia global: Los fundamentos del mundo moderno; Florencia en la época de los Medicis; La formación del mundo moderno; El Renacimiento; el primero de ellos estaba firmado con un historiador de su misma generación, R. Romano, estudioso de las relaciones comerciales en la época moderna en Europa y en la América española. Tenenti ha publicado monografías (Venezia e i corsari, 1961, colecciones de artículos (Credence, ideologie, libertinismi tra medioevo ed eta moderna, 1978; Stato: un'idea, una logica. Dal comune italiano all'assolutismo francese, 1987 y editado a clásicos como Il libri della famiglia de L. B. Alberti, 1969. Es también especialista en temas económicos, como el del

  10. Puentes con vigas pretensadas

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1965-07-01

    Full Text Available This paper describes one of the three bridges which Hidrocivil, S. A., has built in Catalonia (northern Spain, over the river Ripoll. The other two bridges are very similar to this one, both in construction and design, and show only minor adjustments to the local topography. The contracting firm proposed several alterations in the prefabrication and constructional procedure, in relation to the initial project, and these changes were accepted. The main feature of these projects is the use of prestressed beams, built at the workshop in sections, and joined together by means of sixty 7 mm cables in each beam. As the shear forces are more acute at the joints, the end of each section has a kind of diaphragm, to provide a large contact area, and hence greater surface to transmit the shear forces. The methods of construction are also of interest. Briefly, they involve building the bridge piles, and use these to support a provisional structure with transversal movement. This provisional structure, in turn, served as platform for two bridge cranes, which lifted the girders to their final location. After the first span was completed, the deck was concreted and the auxiliary structure pushed forward to the next span, to repeat the same operations. This arrangement saved the use of provisional framework.En este trabajo se describe uno de los tres puentes que Hidrocivil, S. A., ha construido.—previo concurso— en la región catalana; concretamente, el que salva el río Ripoll. Los otros dos no han sido objeto de descripción general por ser muy similares, en lo que a ejecución y concepción se refiere, con la única variante que presentan las características topográficas locales. La empresa propuso ciertas variantes— que fueron aceptadas— en la prefabricación y métodos de construcción. El interés de estas obras se centra en el empleo de vigas pretensadas, prefabricadas en taller por trozos, y solidarizados en el mismo mediante las operaciones

  11. Entrevista con Bernard Vincent.

    Directory of Open Access Journals (Sweden)

    Fernando Colina Pérez

    2006-01-01

    Full Text Available Nacido en París (1941, Bernard Vincent es un historiador de renombre en Europa y América del Sur. Consiguió su agregación universitaria en 1966, y desde sus inicios se centró en la Historia Moderna, particularmente en grupos marginales de la España de los siglos XVI-XVII. Ha residido en nuestro país muchos años. Vincent fue miembro de la sección científica de la Casa de Velázquez inicialmente (1968-1971, algo más tarde director de estudios (1977-1978, y a continuación secretario general (1978-1982 de dicha institución. Asimismo ha encabezado el programa de cooperación francoespañol en ciencias sociales (1993-1996. Por otra parte, ha enseñado en la Universidad de París VII, en varias etapas de su vida; pero, sobre todo, ha pertenecido siempre a centros superiores de investigación: Centre National de la Recherche Scientifique (1976-1978, y a la École des Hautes Études en Sciences Sociales, en donde ha sido director de estudios desde 1988 –era doctor de Estado ya en 1986–, y luego responsable de la Sección de Historia, desde 1996 hasta hoy. Sus colaboraciones con las universidades y centros investigadores españoles han sido constantes hasta el presente. Por añadidura, ha sido miembro del Consejo Nacional de las Universidades en Francia, en lo relativo a la historia moderna y contemporánea (1987-1988, 1992-1995, y es desde hace años miembro de la madrileña Academia de la Historia.

  12. Matrices con entradas enteras e inversa con entradas enteras

    OpenAIRE

    Mora, Walter

    2004-01-01

    Algunos artículos publicados en The American Mathematical Monthly discuten acerca de la construcción de matrices con entradas enteras, valores propios enteros y vectores propios con componentes enteras, en particular en [1] se hace una construcción que además permite construir, de manera sencilla, matrices con entradas enteras cuya inversa también tiene entradas enteras. Este artículo trata de estas últimas construcciones e incluye software en Java para generar y modificar ejemplos y para hac...

  13. IMPEDANCIA ELECTROQUÍMICA - INTERPRETACIÓN DE DIAGRAMAS TÍPICOS CON CIRCUITOS EQUIVALENTES

    Directory of Open Access Journals (Sweden)

    ULISES PIRATOBA MORALES

    2010-01-01

    Full Text Available La Impedancia Electroquímica (IE se viene utilizando cada vez más en la caracterización del desempeño de los materiales principalmente en lo relacionado con electrocatálisis y corrosión. En este trabajo se presenta el análisis físico, analítico y gráfico de uno de los circuitos equivalente más usado para el ajuste de los datos y diagramas de IE. Se indica cómo deducir de los diagramas, algunos valores de parámetros útiles en el proceso de ajuste a la función de transferencia de circuito equivalente típico, y la relación entre estos valores y la forma de los diagramas de impedancia electroquímica. Los procesos desarrollados se aplican luego al análisis de datos impedancia electroquímica de un acero AISI 1055 en HCl al 3% y a diez multicapas de periodo ¿ = 100 nm, depositadas sobre H13 en NaCl al 3%.

  14. Study on the types of craters produced in the impact of projectiles 5,56 SS109, over steel targets AISI-SAE 1045; Estudio de los tipos de crateres obtenidos en el impacto de proyectiles 5,56 SS109, sobre blancos de acero AISI-SAE 1045

    Energy Technology Data Exchange (ETDEWEB)

    Castro, A.; Espejo, E.; Martinez, L. [Universidad Nacional de Colombia. Santa Fe de Bogota (Colombia)

    2000-07-01

    The present work describes the morphology and formation of the types of craters obtained with the impact of projectiles 5,56 SS109 over seven steel plates AISI-SAE 1045 that received different cycles of heat treatment. A comparison between the type of deformation and fracture structures and the ones generated by the impact of this projectiles over one steel armor plate was made. Each one of the craters was characterized by visual and metallography observation. The influence of the plate microstructure on the efficiency for stopping the projectile and the mechanism of craters formation was evaluated. (Author) 10 refs.

  15. Development of Nb{sub 2}O{sub 5}|Cu composite as AISI 1020 steel thermal spray coating for protection against corrosion by soil in buried structures; Desenvolvimento e uso do composito de Nb{sub 2}O{sub 5}|Cu como revestimento aplicado por aspersao termica sobre o aco AISI 1020 para protecao contra a corrosao pelo solo em estruturas enterradas

    Energy Technology Data Exchange (ETDEWEB)

    Regis Junior, Oscar [Universidade Tecnologica Federal do Parana, Ponta Grossa, PR (Brazil). Dept. de Mecanica; Silva, Jose Maurilio da; Portella, Kleber Franke [Instituto de Tecnologia para o Desenvolvimento, Curitiba, PR (Brazil). Dept. de Pesquisa em Engenharia Civil; Paredes, Ramon Sigifredo Cortes, E-mail: regis@utfpr.edu.br [Universidade Federal do Parana, Curitiba, PR (Brazil). Dept. de Mecanica

    2012-07-01

    An Nb{sub 2}O|Cu corrosion-resistant coating was developed and applied onto AISI 1020 steel substrate by Powder Flame Spray. A galvanostatic electrochemical technique was employed, with and without ohmic drop, in four different soils (two corrosively aggressive and two less aggressive). Behavior of coatings in different soils was compared using a cathodic hydrogen reduction reaction (equilibrium potential, overvoltage and exchange current density) focusing on the effect of ohmic drop. Results allow recommendation of Nb{sub 2}O{sub 5}|Cu composite for use in buried structure protection. (author)

  16. con el aborto provocado

    Directory of Open Access Journals (Sweden)

    José Luis Redondo Calderón

    2008-01-01

    Full Text Available Las vacunas de células diploides humanas (WI-38, MRC-5 tienen un origen éticamente objetable, dado que dichas células proceden de abortos provocados. Entre ellas destacan vacunas empleadas contra rubéola, sarampión, parotiditis, rabia, poliomielitis, viruela, hepatitis A, varicela y herpes zóster. Actualmente se encuentran en desarrollo otras vacunas cultivadas en células (293, PER.C6 transformadas mediante virus, procedentes de abortos. Entre ellas hay vacunas contra la gripe, virus respiratorio sincitial, parainfl uenza, HIV, virus del Nilo Occidental, virus Ébola, Marburg y Lassa, hepatitis B y C, glosopeda, encefalitis japonesa, dengue, tuberculosis, carbunco, peste, tétanos y paludismo. También con igual origen se trabaja en la elaboración de anticuerpos monoclonales y otras proteínas, terapia génica y genómica. Existe la tecnología necesaria para producir todo lo descrito sin recurrir a abortos provocados. Debe indicarse en los prospectos de vacunas y otros productos el origen de las células empleadas. Debe facilitarse el acceso a las vacunas existentes no cultivadas en células procedentes de abortos provocados. Debe potenciarse la investigación de opciones en aquellos casos en los que no exista una vacuna no originada en células procedentes de abortos provocados. Debe potenciarse la elaboración de anticuerpos monoclonales y de otras proteínas, así como la terapia génica y la genómica sin recurrir a células procedentes de abortos provocados. No sería consecuente rechazar productos obtenidos a partir de células troncales embrionarias y aceptar los originados en células procedentes de abortos provocados. Se debe evitar que la biotecnología basada en el aborto provocado invada todos los terrenos de la medicina.

  17. Perfil del trabajador con discapacidad

    OpenAIRE

    CAPGEMINI; FUNDACIÓN ADECCO

    2014-01-01

    Capgemini y la Fundación Adeco analizan y reflexionan sobre empleo de las personas con discapacidad. A pesar de los avances que se están registrando en este ámbito, la situación laboral de las personas con discapacidad aún está lejos de alcanzar las cotas deseadas de normalización: mientras que la tasa de actividad de las personas sin discapacidad se sitúa en el 76,3%, la de las que sí la tienen desciende bruscamente hasta el 36,5%. En otras palabras, un 63,4% de las personas con discapacidad...

  18. The Stress Distribution and Thermal Behavior of TiBN and TiBN/TiN Coatings in Milling AISI H13 Work Tool Steel

    Institute of Scientific and Technical Information of China (English)

    YAN Hong; HUA Jiang; SHIVPURI Raja

    2005-01-01

    The FEM model of TiBN and TiBN/TiN coated cutting tool in milling of H13 steel was developed. Process variables such as temperature and stress in the coating layer as well as in the substrate were analyzed. The efficacy of the present FEM analysis was verified by conducting controlled milling experiments on AISI H13 to collect the relevant tool life and force data.The results show that the stress in a coated tool can significantly be reduced compared to an uncoated cutting tool,possibly due to surface coatings improving the tribological properties of cutting tools.Coatings with good thermal properties also help to improve the thermal behavior of cutting tool.

  19. Investigation of diffusion kinetics of plasma paste borided AISI 8620 steel using a mixture of B2O3 paste and B4C/SiC

    Indian Academy of Sciences (India)

    Ibrahim Gunes; Sukru Taktak; Cuma Bindal; Yilmaz Yalcin; Sukru Ulker; Yusuf Kayali

    2013-06-01

    In the present study, AISI 8620 steel was plasma paste borided by using various B2O3 paste mixture. The plasma paste boriding process was carried out in a dc plasma system at temperatures of 973, 1023 and 1073 K for 2, 5 and 7 h in a gas mixture of 70% H2 -30% Ar under a constant pressure of 10 mbar. The properties of the boride layer were evaluated by optical microscopy, X-ray diffraction, Vickers micro-hardness tester and the growth kinetics of the boride layers. X-ray diffraction analysis of boride layers on the surface of the steel revealed FeB and Fe2B phases. Depending on temperature and layer thickness, the activation energies of boron in steel were found to be 124.7 kJ/mol for 100% B2O3.

  20. Multi-Objective Optimization ( Surface Roughness & Material Removal Rate of Aisi 202 Grade Stainless Steel in Cnc Turning Using Extended Taguchi Method And Grey Analysis

    Directory of Open Access Journals (Sweden)

    Er.Ankush Aggarwal

    2014-07-01

    Full Text Available The present study applied Taguchi method through a case study in straight turning of AISI 202 stainless steel bar on CNC Machine ( Mfd by ACE DESIGNERS using Titanium Carbide tool for the optimization of Material removal rate, Surface Roughness and tool wear process parameter.The study aimed at evaluating the best process environment which could simultaneously satisfy requirements of both quality as well as productivity with special emphasis on maximizing material removal rate and minimizing surface roughness and tool flank wear at various combination of cutting speed, feed, depth of cut. The predicted optimal setting ensured maximum MRR and minimum surface roughness and tool wear. Since optimum material removal rate is desired, so higher the better criteria of Taguchi signal to noise ratio is used for MRR – SNs = -10 log(Sy2 /n

  1. EXAMINATION OF THE CUTTING FORCES OF AISI 304 AUSTENITIC STAINLESS STEEL IN THE TURNING PROCESS WITH TITANIUM CARBIDE COATED CUTTING TOOLS

    Directory of Open Access Journals (Sweden)

    Özgür TEKASLAN

    2007-02-01

    Full Text Available In this study, cutting forces occurring in the machining process of AISI 304 austenitic stainless steel specimen using titanium coated cutting tools are investigated experimentally and the results are compared to theoretical calculations. In the experimental study, various cutting speeds, feed rates and cutting depths are considered. Cutting forces are measured by 3-dimensional Kistler dynamometer. In the theoretically study, cutting forces are determined by Kienzle formulation. Consequently, it is found that the calculation of cutting forces in the theoretical method doesn't yield the exact results because of various factors and there is a % 25 average differences in accordance with the experimental results. Hence it is evaluated that the experimental technique in the determination of cutting forces yields more accurate results.

  2. Friction and wear of selected metals and alloys in sliding contact with AISI 440 C stainless steel in liquid methane and in liquid natural gas

    Science.gov (United States)

    Wisander, D. W.

    1978-01-01

    Aluminum, titanium, beryllium, nickel, iron, copper, and several copper alloys were run in sliding contact with AISI 440C in liquid methane and natural gas. All of the metals run except copper and the copper alloys of tin and tin-lead showed severely galled wear scars. Friction coefficients varied from 0.2 to 1.0, the lowest being for copper, copper-17 wt. % tin, and copper-8 wt. % tin-22 wt. % lead. The wear rate for copper was two orders of magnitude lower than that of the other metals run. An additional order of magnitude of wear reduction was achieved by the addition of tin and/or lead to copper.

  3. Optimization of pulsed current GTAW process parameters for sintered hot forged AISI 4135 P/M steel welds by simulated annealing and genetic algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Joby; Muthukumaran, S. [National Institute of Technology, Tamil Nadu (India)

    2016-01-15

    Abundant improvements have occurred in materials handling, especially in metal joining. Pulsed current gas tungsten arc welding (PCGTAW) is one of the consequential fusion techniques. In this work, PCGTAW of AISI 4135 steel engendered through powder metallurgy (P/M) has been executed, and the process parameters have been highlighted applying Taguchi's L9 orthogonal array. The results show that the peak current (Ip), gas flow rate (GFR), welding speed (WS) and base current (Ib) are the critical constraints in strong determinant of the Tensile strength (TS) as well as percentage of elongation (% Elong) of the joint. The practical impact of applying Genetic algorithm (GA) and Simulated annealing (SA) to PCGTAW process has been authenticated by means of calculating the deviation between predicted and experimental welding process parameters.

  4. An estimation of stress intensity factor in a clamped SE(T)specimen through numerical simulation and experimental verification: case of FCGR of AISI H11 tool steel

    Institute of Scientific and Technical Information of China (English)

    Masood Shah; Catherine Mabru; Farhad Rezai-Aria; Ines Souki; Riffat Asim Pasha

    2012-01-01

    A finite element analysis of stress intensity factors (KI) in clamped SE(T)c specimens (dog bone profile) is presented.A J-integral approach is used to calculate the values of stress intensity factors valid for 0.125≤a/W≤0.625.A detailed comparison is made with the work of other researchers on rectangular specimens.Different boundary conditions are explored to best describe the real conditions in the laboratory.A sensitivity study is also presented to explore the effects of variation in specimen position in the grips of the testing machine.Finally the numerically calculated SIF is used to determine an FCGR curve for AISI H11 tool steel on SE(T)c specimens and compared with C(T) specimen of the same material.

  5. Microstructure and property modifications of an AISI H13 (4Cr5MoSiV) steel induced by pulsed electron beam treatment

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Kemin; Zou Jianxin; Grosdidier, Thierry; Dong Chuang [School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Shanghai Engineering Research Center of Mg Materials and Applications and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China) and Laboratoire d' Etude des Textures et Applications aux Materiaux (LETAM, CNRS 3143), Universite Paul Verlaine Metz, Ile du Saulcy, 57045 Metz (France); Laboratoire d' Etude des Textures et Applications aux Materiaux (LETAM, CNRS 3143), Universite Paul Verlaine Metz, Ile du Saulcy, 57045 Metz (France) and Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116024 (China); Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116024 (China)

    2010-11-15

    In the present work, surface modifications generated by the low energy high current pulsed electron beam (LEHCPEB) treatments have been investigated on an AISI H13 (4Cr5MoSiV) steel. From the observations of scanning electron microscopy, x-ray diffraction, and electron back scattering diffraction determinations, it could be established that the final structure in the melted layer is a mixture of ultrafine {delta} phase, martensite, and residual austenite. The formation of the heterogeneous microstructures on the surface layer is related to the very rapid heating, melting, solidification, and cooling induced by the LEHCPEB irradiation. After the LEHCPEB treatment, the wear resistance of the steel effectively improved. This can be mainly attributed to the higher hardness of the ultrafine structures formed on the top surface and the hardened subsurface layers after the treatment.

  6. Effect of a Shot Peening Pre Treatment on the Fatigue Behaviour of Hard Chromium on Electroless Nickel Interlayer Coated AISI 4340 Aeronautical Steel

    Directory of Open Access Journals (Sweden)

    Nascimento Marcelino P.

    2002-01-01

    Full Text Available Multiple layer systems of coatings are considered to have larger resistance to crack propagation in comparison to coatings with simple layer. With regard to fatigue, it is possible to improve the resistance of a component with the application of shot peening treatment, whose compressive residual stresses delay or eliminate the initiation and propagation of fatigue cracks. The aim of this study is to analyse the effects on rotating bending fatigue behaviour of hard chromium fraction three-quarters electroless nickel multilayer system coated AISI 4340 high strength steel submitted to shot peening pre treatment. Results indicated that the interaction between the shot peening process with the multilayer system was not satisfactory, resulting in intense delamination. Fracture surface analysis by SEM was performed toward to identify the fatigue crack origin, as well as the coating-substrate delamination process.

  7. Comparison of surface roughness and chip characteristics obtained under different modes of lubrication during hard turning of AISI H13 tool work steel.

    Science.gov (United States)

    Raj, Anil; Wins, K. Leo Dev; Varadarajan, A. S.

    2016-09-01

    Surface roughness is one of the important parameters, which not only affects the service life of a component but also serves as a good index of machinability. Near Dry Machining, methods (NDM) are considered as sustainable alternative for workshops trying to bring down their dependence on cutting fluids and the hazards associated with their indiscriminate usage. The present work presents a comparison of the surface roughness and chip characteristics during hard turning of AISI H13 tool work steel using hard metal inserts under two popular NDM techniques namely the minimal fluid application and the Minimum Quantity Lubrication technique(MQL) using an experiment designed based on Taguchi's techniques. The statistical method of analysis of variance (ANOVA) was used to determine the relative significance of input parameters consisting of cutting speed, feed and depth of cut on the attainable surface finish and the chip characteristics. It was observed that the performance during minimal fluid application was better than that during MQL application.

  8. Influence of minimum quantity of lubricant (MQL on tool life of carbide cutting tools during milling process of steel AISI 1018

    Directory of Open Access Journals (Sweden)

    Diego Núñez

    2017-03-01

    Full Text Available Nowadays, high productivity of machining is an important issue to obtain economic benefits in the industry. This purpose could be reached with high cutting velocity and feed rate. However, the inherently behavior produce high temperatures in the interface of couple cutting tool/workpiece. Many cutting fluids have been developed to control temperature in process and increase tool life. The objective of this paper is to compare the carbide milling tool wear using different systems cutting fluids: flood and minimum quantity of lubrication (MQL. The values of carbide milling cutting tool wear was evaluate according with the standard ISO 8688-1 1989. The experimental results showed that using MQL reduces significantly (about 40% tool wear in milling AISI 1018 steel at industrial cutting conditions.

  9. MICROSTRUCTURE AND CORROSION RESISTANCE OF CHROMIUM NITRIDES OBTAINED BY VACUUM GAS NITRIDING OF ELECTROLYTIC CHROMIUM DEPOSITED ON AISI H13 STEEL

    Directory of Open Access Journals (Sweden)

    H. Cifuentes

    2013-06-01

    Full Text Available In this scientific research paper, the microstructure and corrosion resistance of chromium nitrides obtained from a duplex treatment consisting of an electroplated hard chromium coating applied on a steel AISI H13 follow by a thermochemical treatment in vacuum using NH3 as precursor gas of nitrogen, is evaluated. This type of duplex treatments combine the benefits of each individual treatment in order to obtain, with this synergic effect, compounds type CrxN more economic than those obtained by other kind of treatments e.g. physical vapor deposition (PVD. The results obtained by X-Ray Diffraction (XRD indicate the surface and subsurface transformation of the electrolytic hard chromium coating by formation of CrN and Cr2N phases. Likewise, potentiodynamic polarization tests indicate an increase in corrosion resistance of such kind of compounds in comparison with the obtained results with electroplated hard chromium.

  10. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  11. On the corrosion resistance of AISI 316L-type stainless steel coated with manganese and annealed with flow of oxygen

    Science.gov (United States)

    Savaloni, Hadi; Agha-Taheri, Ensieh; Abdi, Fateme

    2016-06-01

    AISI 316L-type stainless steel was coated with 300-nm-thick Mn thin films and post-annealed at 673 K with a constant flow of oxygen (250 cm3/min). The films crystallographic and morphological structures were analyzed using X-ray diffraction (XRD) and atomic force microscopy (AFM) before corrosion test and scanning electron microscopy (SEM) after corrosion test. Corrosion behavior of the samples in 0.3, 0.5 and 0.6 M NaCl solutions was investigated by means of potentiodynamic and electrochemical impedance spectroscopy (EIS) techniques. Results showed that the corrosion inhibition of annealed Mn/SS316L in all NaCl solutions with different concentrations is higher than that of bare SS316L. A correlation is achieved between the structural variation of the films with the potentiodynamic and EIS corrosion results.

  12. Effect of Welding Processes on Tensile and Impact Properties, Hardness and Microstructure of AISI 409M Ferritic Stainless Joints Fabricated by Duplex Stainless Steel Filler Metal

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; K Shanmugam; V Balasubramanian

    2009-01-01

    The effect of welding processes such as shielded metal arc welding, gas metal arc welding and gas tungsten arc welding on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade is studied. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the welded joints have been evaluated and the results are compared. From this investigatio.n, it is found that gas tungsten arc welded joints of ferritic stainless steel have superior tensile and impact properties compared with shielded metal are and gas metal arc welded joints and this is mainly due to the presence of finer grains in fusion zone and heat affected zone.

  13. Application of orthogonal array technique and particle swarm optimization approach in surface roughness modification when face milling AISI1045 steel parts

    Science.gov (United States)

    Azadi Moghaddam, Masoud; Kolahan, Farhad

    2016-12-01

    Face milling is an important and common machining operation because of its versatility and capability to produce various surfaces. Face milling is a machining process of removing material by the relative motion between a work piece and rotating cutter with multiple cutting edges. It is an interrupted cutting operation in which the teeth of the milling cutter enter and exit the work piece during each revolution. This paper is concerned with the experimental and numerical study of face milling of AISI1045. The proposed approach is based on statistical analysis on the experimental data gathered using Taguchi design matrix. Surface roughness is the most important performance characteristics of the face milling process. In this study the effect of input face milling process parameters on surface roughness of AISI1045 steel milled parts have been studied. The input parameters are cutting speed ( v), feed rate ( f z ) and depth of cut ( a p ). The experimental data are gathered using Taguchi L9 design matrix. In order to establish the relations between the input and the output parameters, various regression functions have been fitted on the data based on output characteristics. The significance of the process parameters on the quality characteristics of the process was also evaluated quantitatively using the analysis of variance method. Then, statistical analysis and validation experiments have been carried out to compare and select the best and most fitted models. In the last section of this research, mathematical model has been developed for surface roughness prediction using particle swarm optimization (PSO) on the basis of experimental results. The model developed for optimization has been validated by confirmation experiments. It has been found that the predicted roughness using PSO is in good agreement with the actual surface roughness.

  14. Decapado del acero inoxidable AISI 316L utilizando una mezcla ecológica de H2O2-H2SO4-HF

    Directory of Open Access Journals (Sweden)

    Gómez, P. P.

    2005-12-01

    Full Text Available This study reports the pickling of austenitic AISI 316L stainless steel (SS using a mixture of hydrogen peroxide (H2O2, sulphuric acid (H2SO4 and hydrofluoric acid (HF at pH 2.0. The stability of H2O2 was also studied using different concentrations of ferric ion from 0 to 40 g/l and temperature from 25 to 60 °C. The pickling rate at 50 °C in the presence and absence of 40 g/l ferric ion was 2.6 and 0.2 mg/dm2 day (mdd, respectively. p-Toluene sulphonic acid was used as stabilizer of H2O2.En la presente investigación se estudia el decapado del acero inoxidable AISI 316L utilizando una mezcla de agua oxigenada (H2O2 y los ácidos sulfúrico (H2SO4 y fluorhídrico (HF a pH 2,0. La estabilidad de la mezcla H2O2-H2SO4-HF se ha ensayado variando el contenido de iones férrico de O a 40 g/l y la temperatura de 25 a 60 °C. La velocidad de decapado a 50 °C ha sido de 2,6 y 0,2 mg/dm2 día (mdd, en ausencia y presencia de 40 g/l de iones férrico, respectivamente. Se ha utilizado el ácido p-toluen sulfónico como estabilizante del H2O2.

  15. Varicela sobreinfectada con Staphylococcus Aureus

    Directory of Open Access Journals (Sweden)

    Fabiana A. Bellot

    2010-12-01

    Full Text Available Paciente masculino de 5 años de edad internado por presentar un cuadro clínico de más o menos cuatro días de evolución caracterizado por la presencia de fiebre, malestar general, anorexia y dolor abdominal leve complicándose con la aparición de erupciones en piel, cuero cabelludo, cara, tronco y mucosas de características maculo-papulosas eritematosas con un halo eritematoso. Las mismas de tamaños y formas variables, tensas, con contenido purulento, acompañado de fiebre de 38 C°. Al examen físico se evidencian: lesiones dérmicas sobreinfectadas con secreción purulenta en algunas regiones del cuerpo (rostro y tronco. El diagnóstico de ingreso fue varicela sobreinfectada por estafilococo.

  16. Deposición metálica de Stellite grado 6 sobre AISI 316 en superficies planas mediante soldadura por fricción. // Metallic deposition of Stellite degree 6 on AISI 316 in plane surfaces by means of friction welding.

    Directory of Open Access Journals (Sweden)

    J. Cabello Eras

    2003-01-01

    Full Text Available En el presente trabajo se realiza un estudio del proceso de deposición metálica de Stellite grado 6 sobre una superficie deacero inoxidable AISI 316 a través de la soldadura por fricción. Se estudiaron distintas combinaciones de parámetros desoldadura tales como, velocidad de rotación de la barra de material de aportación, velocidad transversal del sustrato, tiempode calentamiento, presión de apriete de la barra contra el sustrato y los depósitos obtenidos son sometidos a un análisismetalográfico en la zona de interfase y a una prueba de doblado para comprobar su adhesión al metal base.Palabras claves: Soldadura por fricción, depósitos metálicos._____________________________________________________________________________AbstractPresently work carried out a study of the process of metallic deposition of Stellite degree 6 on a surface of stainlesssteel AISI 316 through the welding by friction. Different combinations of welding parameters were studied as:rotation speed of the contribution material bar, sustain traverse speed, time of heating, pressure of the bar againstthe sustain. The obtained deposits are subject to metalografic analysis in the interface area and to bending test inorder to check their adhesion to the metal bases.Key words: Friction welding, metallic deposits.

  17. con mala calidad de vida

    Directory of Open Access Journals (Sweden)

    Agustín Martín-Rodríguez

    2007-01-01

    Full Text Available En este estudio ex post facto se ha analizado si los familiares de pacientes con mala calidad de vida presentan diferencias en las variables clínicas de personalidad y relaciones familiares en función de que el paciente haya estado o no ingresado en una Unidad de Cuidados Intensivos. Seleccionamos dos grupos: 29 familiares de pacientes traumatizados graves transcurridos cuatro años de su ingreso en una UCI de Traumatología y con mala calidad de vida (debido a secuelas físicas y/o psicológicas tras el ingreso, tales como traumatismos craneoencefálicos, politraumatismos y tetraplejias traumáticas y 32 familiares de pacientes con mala calidad de vida con cuatro años de evolución de su enfermedad física (hipertensión, diabetes, artritis reumatoide y síndrome de intestino irritable que no han estado ingresados en la UCI. Para alcanzar nuestro objetivo empleamos una Encuesta Psicosocial y los siguientes instrumentos: Cuestionario de Análisis Clínico, Escala de Clima Social en la Familia y Escala de Adaptación Psicosocial de la Enfermedad. Los resultados mostraron que los familiares de pacientes con mala calidad de vida que estuvieron ingresados en la UCI hace cuatro años, presentan diferencias significativas en las variables agitación y expresividad comparados con los familiares de pacientes con mala calidad de vida que no han estado ingresados en la UCI.

  18. Encuentro con el tiempo: Adagio con variaciones de Alfredo Aracil

    Directory of Open Access Journals (Sweden)

    Rosa María Rodríguez Hernández

    2012-01-01

    Full Text Available Examinando analíticamente la obra sinfónica Adagio con variaciones de Aracil, estudiaremos los principales componentes para concluir con una evaluación de los mismos. A través de la cronología de la obra de Aracil175, observamos la importancia que adquiere en su trayectoria la memoria; su pensamiento va siempre unido a ésta. Uno de sus recursos principales es la cita; es Adagio con variaciones donde claramente observaremos la memoria lejana e inmediata al tiempo: Wagner es el punto de referencia al pasado, Wolf impulsa hacia el presente, y, Aracil advierte el devenir en cada una de sus variaciones.

  19. Los nenes con los zombies, las nenas con los vampiros

    OpenAIRE

    López Corral, Manuela

    2012-01-01

    En este artículo nos circunscribiremos, dentro de este género literario, a las sagas de reciente salida editorial y, con mayor precisión, a las sagas de novelas románticas para adolescentes tales como Crepúsculo (Stephenie Meyer, 2005), Hush Hush (Becca Fitzpatrick, 2009), Cazadores de Sombras (Cassandra Clare, 2007), Fallen (Lauren Kate, 2010), y otras similares, dejando de lado sagas con otro tipo de particularidades como los citados libros de Harry Potter o los pertenecientes a la trilogía...

  20. Effect of ferric ions in AISI 316L stainless steel pickling using an environmentally-friendly H{sub 2}SO{sub 4}-HF-H{sub 2}O{sub 2} mixture

    Energy Technology Data Exchange (ETDEWEB)

    Narvaez, L. [Metallurgical Institute, UASLP Avda. Sierra Leona 550, 78210 San Luis Potosi (Mexico); Cano, E.; Bastidas, J.M. [CENIM-National Centre for Metallurgical Research (CSIC) Avda. Gregorio del Amo 8, 28040 Madrid (Spain)

    2003-02-01

    A mixture of hydrogen peroxide, sulphuric and hydrofluoric acids has been used as pickling solution at pH 2.0 for AISI 316L austenitic stainless steel (SS). The stability of the H{sub 2}SO{sub 4}-HF-H{sub 2}O{sub 2} mixture is assessed varying the ferric ions content from 0 to 40 g/L, the temperature from 25 to 60 C, and with and without stirring of the pickling solution. The AISI 316L SS pickling rate at 50 C was 2.6 and 0.2 mg/dm{sup 2} day (mdd) in the absence and presence of 40 g/L ferric ions, respectively. p-toluene sulphonic acid (PTSA) has been used as stabiliser of hydrogen peroxide. (Abstract Copyright [2003], Wiley Periodicals, Inc.) [German] Es ist ein Gemisch mit einem pH-Wert von 2.0 aus Wasserstoffperoxid, Schwefelsaeure und Fluorwasserstoffsaeure als Beizloesung fuer nichtrostenden Stahl AISI 316L angewandt worden. Die Stabilitaet des Gemisches H{sub 2}SO{sub 4}-HF-H{sub 2}O{sub 2} haengt vom Gehalt der dreiwertigen Eisenionen, zwischen 0 und 40 g/L, von der Temperatur, zwischen 25 und 60 C, und von der Ruehrintensitaet der Beizloesung ab. Die Beizgeschwindigkeit des nichtrostenden Stahls AISI 316L bei 50 C lag bei 2.6 bzw. 0.2 mg/dm{sup 2} taeglich (mdd), je nachdem, ob 40 g/L dreiwertige Eisenionen enthalten waren oder nicht. Als Stabilisator des Wasserstoffperoxids ist para-Toluensulfonsaeure (PTSA) eingesetzt worden. (Abstract Copyright [2003], Wiley Periodicals, Inc.)

  1. The effect of thermal annealing on the adherence of $Al_2O_3$-films deposited by low-pressure, metal-organic, chemical-vapor deposition on AISI 304

    NARCIS (Netherlands)

    Haanappel, V.A.C.; Vendel, van de D.; Corbach, van H.D.; Fransen, T.; Gellings, P.J.

    1995-01-01

    Thin alumina films, deposited at 280°C by low-pressure, metal-organic, chemical-vapor deposition on stainless steel, type AISI 304, were annealed at 0.17 kPa in a nitrogen atmosphere for 2,4, and 17 hr at 600, 700, and 800°C. The effect of the annealing process on the adhesion of the thin alumina fi

  2. Entrevista con Hans Robert Jauss.

    Directory of Open Access Journals (Sweden)

    - Consejo de Redacción

    1997-01-01

    Full Text Available El importante teórico y crítico literario alemán nació en 1921. Tras el largo paréntesis de la segunda guerra mundial, Jauss realizará sus estudios superiores, a partir de 1948, en Heidelberg, licenciándose en filología románica. Se doctora pronto con una tesis, publicada en 1955, sobre el tiempo y el recuerdo en la obra capital de Marcel Proust, En busca del tiempo perdido, y se habilita en 1957 con un trabajo sobre la epopeya animal en la Edad Media. A continuación, escribe un conjunto de estudios sobre la alegoría, y codirige con el gran especialista Erich Kohler una monumental historia de la literatura medieval, campo al que ha dedicado otros artículos, a la par que proseguía sus investigaciones iniciales.

  3. Tratamiento con implantes Leader-Nano en paciente con oligodoncia

    Directory of Open Access Journals (Sweden)

    Salvador Javier Santos Medina

    2015-03-01

    Full Text Available Los implantes dentales de titanio han revolucionado el mundo de la rehabilitación desde su surgimiento. De manera particular, el empleo de implantes de carga inmediata acorta el tiempo quirúrgico y protésico, con el consiguiente bienestar estético. Se presenta el caso de una paciente femenina de 32 años de edad, con antecedentes de oligodoncia de ambos incisivos laterales superiores y portadora de prótesis parcial acrílica. Fue atendida por el equipo multidisciplinario de implantes en la Clínica Estomatológica Docente “3 de Octubre” y se le realizó tratamiento de rehabilitación integral con implantes Leader-Nano y prótesis fija con corona acrílica sobre dichos implantes. La implantología fue satisfactoria en la paciente; la mejoría estética y funcional, así como la satisfacción de la paciente, fueron los principales logros obtenidos

  4. ARLAB: Laboratorio con Realidad Aumentada

    OpenAIRE

    Rodríguez Calderón, Rosalino; Santillana Arbesú, Rafael

    2013-01-01

    ResumenARLAB es una innovación que incorporar tecnología de realidad aumentada a los experimentos clásicos decontrol y automatización industrial, permitiendo integrar y que interactúen varias tecnologías desarrollándoseexperimentos mixtos, parte real y parte virtual en 3D, que se visualiza con un dispositivo inteligente, como lo esun celular o tableta electrónica; con el fin de generar una visión del conocimiento más profunda y clara.

  5. Huevos enriquecidos con omega 3

    OpenAIRE

    Viteri, Evelyn

    2013-01-01

    El presente trabajo es una contribución al estudio de usos de ingredientes no tradicionales; harina de algas, Macrocystis pyrifera, y la inclusión en raciones para aves de postura destinado a aumentar la concentración de omega 3 del huevo. Objetivo: Evaluar en la alimentación de la gallina la inclusión de harina de alga marina Macrocystis pyrifera con el fin de aumentar el valor de omega 3 en el huevo, y el grado de aceptación de un producto elaborado con el mismo en estudiante...

  6. con dietas suplementadas con Cromo-L-metionina

    Directory of Open Access Journals (Sweden)

    Ram\\u00F3n Garc\\u00EDa-Castillo

    2006-01-01

    Full Text Available Un total de 48 cerdos (Sus scrofa domesticus; 24 machos castrados y 24 hembras cruzados (Yorkshire, Hampshire, Duroc y Landrace de 3,5 a 4,0 meses de edad y 60,0 ± 5,0 kg PV en finalización. Se alimentaron con dietas isoproteícas (14,5 % PC e isoenergéticas (3.400 kcal EM/kg de MS, adicionadas con Cr-L-metionina (MiCroPlex® (0, 200, 400 y 600 ppb. El experimento tuvo una duración de 45 días y se realizó de agosto a noviembre del 2002 en las instalaciones de la Universidad Autónoma Agraria Antonio Narro, localizada en Saltillo, Coahuila, México. Al tener los animales aproximadamente 95 kg PV, se tomó muestra de 15 ml de sangre por cada animal para determinar la concentración de glucosa, ácido úrico, creatinina, urea, proteinas totales y colesterol. Se aplicó un diseño completamente al azar con arreglo factorial 2 x 4; dos para el factor sexo y cuatro para nivel de cromo. Los metabolitos en suero no fueron afectados (P>0,05 por el factor sexo. La glucosa en suero disminuyó (P<0,05 y el colesterol incrementó (P<0,05 con cromo en la dieta. Se concluye que el Cr incrementa el metabolismo de glucosa y disminuye el de colesterol, con lo cual puede haber energía disponible para síntesis de proteína la cual es necesaria para el crecimiento de los animales

  7. Estudo do comportamento eletroquímico de azóis para o aço inoxidável AISI 430 em H2SO4 1 mol L-1 Study of electrochemical behavior of azoles for AISI 430 stainless steel in H2SO4 1 mol L-1

    Directory of Open Access Journals (Sweden)

    Martha Tussolini

    2010-03-01

    Full Text Available A corrosão é um processo indesejável que ocorre em materiais metálicos. Nesse trabalho, estudou-se o efeito inibidor do benzotriazol (BTAH, benzimidazol (BZM e indol em diferentes concentrações para o aço inoxidável AISI 430 em H2SO4 1 mol L-1. Foram empregadas as técnicas de: polarização potenciostática anódica, espectroscopia de impedância eletroquímica, microscopia óptica e eletrônica de varredura. As curvas de polarização potenciostática anódica mostraram que o BTAH, BZM e Indol atuam como inibidores de corrosão para o aço AISI 430, nas concentrações de 1x10-3 e 5x10-4 mol L-1, não apresentando inibição significativa para as concentrações iguais ou inferiores a 1x10-4 mol L-1. O aumento da eficiência inibidora em relação às substâncias estudadas seguiu a seguinte ordem: Indol Corrosion is an undesirable process that occurs in metallic materials. Studied was the effect of inhibiting Benzotriazole (BTAH, Benzimidazole (BZM and Indole in different concentrations for the stainless steel (SS AISI 430 in H2SO4 1 mol L-1. The techniques employed this research were: anodic potenciostatic polarisation, electrochemical impedance spectroscopy, optical microscopy and scanning electron microscopy. The curves of anodic polarisation showed that BTAH, BZM and Indol act as corrosion inhibitors for 430 SS, at concentrations of 1x10-3 and 5x10-4 mol L-1, but do not inhibit corrosion for concentrations equal to or less than 1x10-4 mol L-1. The in-crease of the efficiency in relation to the inhibitory substances studied followed this order: Indol

  8. The effect of CO{sub 2} laser beam welded AISI 316L austenitic stainless steel on the viability of fibroblast cells, in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Köse, Ceyhun, E-mail: ceyhun.kose@gop.edu.tr [Faculty of Natural Sciences and Engineering, Department of Mechanical Engineering, Gaziosmanpaşa University, Tokat (Turkey); Kaçar, Ramazan, E-mail: rkacar@karabuk.edu.tr [Faculty of Technology Department of Manufacturing Engineering, Karabuk University, Karabuk 78050 (Turkey); Zorba, Aslı Pınar, E-mail: aslipinarzorba@gmail.com [Graduate School of Natural and Applied Sciences, Department of Bioengineering Cell Culture and Tissue Engineering, Yıldız Technical University, Istanbul (Turkey); Bağırova, Melahat, E-mail: mbagir@yildiz.edu.tr [Department of Bioengineering Cell Culture and Tissue Engineering, Yıldız Technical University, Istanbul (Turkey); Allahverdiyev, Adil M., E-mail: adil@yildiz.edu.tr [Department of Bioengineering Cell Culture and Tissue Engineering, Yıldız Technical University, Istanbul (Turkey)

    2016-03-01

    It has been determined by the literature research that there is no clinical study on the in vivo and in vitro interaction of the cells with the laser beam welded joints of AISI 316L biomaterial. It is used as a prosthesis and implant material and that has adequate mechanical properties and corrosion resistance characteristics. Therefore, the interaction of the CO{sub 2} laser beam welded samples and samples of the base metal of AISI 316L austenitic stainless steel with L929 fibroblast cells as an element of connective tissue under in vitro conditions has been studied. To study the effect of the base metal and the laser welded test specimens on the viability of the fibroblast cells that act as an element of connective tissues in the body, they were kept in DMEMF-12 medium for 7, 14, 28 days and 18 months. The viability study was experimentally studied using the MTT method for 7, 14, 28 days. In addition, the direct interaction of the fibroblast cells seeded on 6 different plates with the samples was examined with an inverted microscope. The MTT cell viability experiment was repeated on the cells that were in contact with the samples. The statistical relationship was analyzed using a Tukey test for the variance with the GraphPad statistics software. The data regarding metallic ion release were identified with the ICP-MS method after the laser welded and main material samples were kept in cell culture medium for 18 months. The cell viability of the laser welded sample has been detected to be higher than that of the base metal and the control based on 7th day data. However, the laser welded sample's viability of the fibroblast cells has diminished by time during the test period of 14 and 28 days and base metal shows better viability when compared to the laser welded samples. On the other hand, the base metal and the laser welded sample show better cell viability effect when compared to the control group. According to the ICP-MS results of the main material and

  9. Evaluación del springback mediante ensayos de doblado bajo tensión en condiciones de multiaxialidad típicas de los procesos de embutición profunda. Aplicación a chapa de acero inoxidable AISI 304 DDQ

    Directory of Open Access Journals (Sweden)

    Miguel, V.

    2013-06-01

    Full Text Available In this paper, a methodology has been developed for evaluating the springback of AISI 304 DDQ stainless steel sheet based on a bending under tension test. The main difference of the methodology herein carried out is that tests are made under the multiaxial stresses state that take place in deep drawing processes. This affects to the level of stress value in the test and to the hardening state of the sheet. Springback evaluation has been done in two different areas. Bending area has been evaluated from elastic recovery ratio defined as the ratio between the bending radius after and before bending. Bending and unbending extreme has been studied from the measured curvature radius in this area and taking into account the geometric equivalence of the test with the drawing cups process. Results found allow to state that drawing ratio or deformation ratio have a negligible influence on the springback into the range of values experimented here. Bending radius has hardly influence as well while bending angle is the most significant variable. The results obtained are compared to those measured in deep-drawn cups, finding a great agreement.En este trabajo se presenta una metodología para evaluar la recuperación elástica o springback de chapa de acero inoxidable AISI 304 DDQ basada en la realización de ensayos bajo tensión. A diferencia de los estudios existentes en la literatura, los ensayos realizados son efectuados en condiciones multiaxiales típicas de los procesos de embutición de chapa. Esto afecta fundamentalmente a las tensiones involucradas en el proceso así como al estado de endurecimiento que experimenta el material. La evaluación del springback se ha efectuado en dos áreas diferentes. En la zona de doblado se ha evaluado a partir del factor de recuperación definido como la razón entre el radio de doblado y el radio con el que queda finalmente el material. La zona de doblado y desdoblado se ha evaluado en base a la inversa del radio

  10. Un momento con el maestro

    OpenAIRE

    Poblete Garaycochea, Luis; Universidad Nacional Mayor de San Marcos

    2014-01-01

    Quiero comenzar, manifestando mis experiencias de comunicación teniendo como fundamento teórico a Carl ROGERS, "El camino del Ser", obra que me sirvió de inspiración e identificación con su pensamiento en el proceso del desarrollo como ser humano.

  11. A vueltas con Samuel Beckett

    Directory of Open Access Journals (Sweden)

    José María Fernández Cardo

    2010-01-01

    Full Text Available A propósito de la obra de Lourdes Carriedo, Mª Luisa Guerrero, Carmen Méndez y Fabio Vericat(eds.: A vueltas con Beckett. Aproximaciones críticas en su centenario (Madrid, Ediciones de La Discreta,col. «Bártulos», 2009, 362 páginas, ISBN: 978-84-96322-29-5.

  12. The effect of CO2 laser beam welded AISI 316L austenitic stainless steel on the viability of fibroblast cells, in vitro.

    Science.gov (United States)

    Köse, Ceyhun; Kaçar, Ramazan; Zorba, Aslı Pınar; Bağırova, Melahat; Allahverdiyev, Adil M

    2016-03-01

    It has been determined by the literature research that there is no clinical study on the in vivo and in vitro interaction of the cells with the laser beam welded joints of AISI 316L biomaterial. It is used as a prosthesis and implant material and that has adequate mechanical properties and corrosion resistance characteristics. Therefore, the interaction of the CO2 laser beam welded samples and samples of the base metal of AISI 316L austenitic stainless steel with L929 fibroblast cells as an element of connective tissue under in vitro conditions has been studied. To study the effect of the base metal and the laser welded test specimens on the viability of the fibroblast cells that act as an element of connective tissues in the body, they were kept in DMEMF-12 medium for 7, 14, 28 days and 18 months. The viability study was experimentally studied using the MTT method for 7, 14, 28 days. In addition, the direct interaction of the fibroblast cells seeded on 6 different plates with the samples was examined with an inverted microscope. The MTT cell viability experiment was repeated on the cells that were in contact with the samples. The statistical relationship was analyzed using a Tukey test for the variance with the GraphPad statistics software. The data regarding metallic ion release were identified with the ICP-MS method after the laser welded and main material samples were kept in cell culture medium for 18 months. The cell viability of the laser welded sample has been detected to be higher than that of the base metal and the control based on 7th day data. However, the laser welded sample's viability of the fibroblast cells has diminished by time during the test period of 14 and 28 days and base metal shows better viability when compared to the laser welded samples. On the other hand, the base metal and the laser welded sample show better cell viability effect when compared to the control group. According to the ICP-MS results of the main material and laser welded

  13. Nature in corrosion-erosion surface for [TiN/TiAlN]n nanometric multilayers growth on AISI 1045 steel

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, J.C., E-mail: jcaicedoangulo@gmail.com [Thin Films Group Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360, Cali (Colombia); Advanced Materials for Micro and NanoTechnology Research Group Universidad Autonoma de Occidente (Colombia); Cabrera, G. [Thin Films Group Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360, Cali (Colombia); Caicedo, H.H. [Department of Bioengineering, University of Illinois at Chicago, IL 60612 (United States); Department of Anatomy and Cell Biology, University of Illinois at Chicago, IL 60612 (United States); Amaya, C. [Thin Films Group Universidad del Valle, Ciudad Universitaria Melendez, A.A. 25360, Cali (Colombia); Hard Coating Laboratory CDT-ASTIN SENA, Cali (Colombia); Aperador, W. [Ingenieria Mecatronica, Universidad Militar Nueva Granada, Bogota (Colombia)

    2012-04-30

    The aim of this work is to characterize the electrochemical behavior of [TiN/TiAlN]n multilayer coatings under corrosion-erosion condition. The multilayers with bilayer numbers (n) of 2, 6, 12, and 24 and/or bilayer period ({Lambda}) of 1500 nm, 500 nm, 250 nm, 150 nm and 125 nm were deposited by magnetron sputtering technique on Si (100) and AISI 1045 steel substrates. Both, the TiN and the TiAlN structures for multilayer coatings were evaluated via X-ray diffraction analysis. Mechanical and tribological properties were evaluated via nanoindentation measurements and scratch test respectively. Silica particles were used as abrasive material on corrosion-erosion test in 0.5 M of H{sub 2}SO{sub 4} solution at impact angles of 30 Degree-Sign and 90 Degree-Sign over surface. The electrochemical characterization was carried out using polarization resistance technique (Tafel), in order to observe changes in corrosion rate as a function of the bilayer number (n) or the bilayer period ({Lambda}) and the impact angle. Corrosion rate values of 9115 {mu}m y for uncoated steel substrate and 2615 {mu}m y for substrate coated with n = 24 ({Lambda} = 125 nm) under an impact angle of 30 Degree-Sign were found. On the other hand, for an impact angle of 90 Degree-Sign the corrosion rate exhibited 16401 {mu}m y for uncoated steel substrate and 5331 {mu}m y for substrate coated with n = 24 ({Lambda} = 125 nm). This behavior was correlated with the curves of mass loss for both coated samples and the surface damage was analyzed via scanning electron microscopy images for the two different impact angles. These results indicate that TiN/TiAlN multilayer coatings deposited on AISI 1045 steel represent a practical solution for applications in corrosive-erosive environments. - Highlights: Black-Right-Pointing-Pointer Determination of superficial phenomenon that occurs in surface of multilayer films. Black-Right-Pointing-Pointer Innovative multilayer system [TiN/TiAlN]n electrochemical

  14. Con

    DEFF Research Database (Denmark)

    Graudal, Niels

    2016-01-01

    Scientific evidence to support the recommended salt intake of ..., health authorities use BP effects obtained in studies of pre-hypertensive and hypertensive patients to recommend SR in the healthy population and use these biased BP effects in statistical models indirectly to project millions of saved lives. These fantasy projections are in contrast to real data from...

  15. Flank wear study of coating carbides and cermet inserts during the dry high speed turning of AISI 1045 steel; Estudio del desgaste del flanco de carburos recubiertos y cermet durante el torneado de alta velocidad en seco del acero AISI 1045

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Gonzalez, L. W.; Perez-Rodriguez, R.; Zambrano-Robledo, P.; Guerrero-Mata, M.; Dumitrescu, L.

    2011-07-01

    This work deals with the experimental study of the flank wear evolution of two coating carbide inserts and a cermet insert during the dry finishing turning of AISI 1045 steel with 400, 500 and 600 m/min cutting speeds. The results were analyzed using the variance analysis and lineal regression analysis in order to describe the relationship between the flank wear and machining time, obtaining the adjusted model equation. The investigation demonstrated a significant effect of cutting speed and machining time on the flank wear at high speed machining. The three coating layers insert showed the best performance while the two layers insert had the worst behaviour of the cutting tool wear at high cutting speeds. (Author) 19 refs.

  16. Evaluación de Velocidades para la Deposición de FeSi y MoS2 por Triboadhesión en Aceros SAE 4140 y AISI 304 Evaluation of the Velocities Required for the Deposition of FeSi and MoS2 on SAE 4140 and AISI 304 Steels by Triboadhesion

    Directory of Open Access Journals (Sweden)

    J.M. Rodríguez

    2005-01-01

    Full Text Available En este trabajo se presenta la evaluación teórico-experimental de las velocidades y cargas requeridas para la deposición por triboadhesión de FeSi y MoS2 en los aceros SAE 4140 y AISI 304. Para ello se determinó el coeficiente de fricción entre la fresa y el material base. El proceso de deposición mediante la técnica de triboadhesión tiene lugar a causa del calor que se genera por fricción entre una fresa de algodón y un material base. Durante el proceso de fricción se provocan altas temperaturas instantáneas en la interfase de la fresa y el material base. En el estudio, se demuestra experimentalmente la deposición de material de aporte, utilizando las velocidades obtenidas de un análisis teórico.In this work a theoretical and experimental evaluation of the velocities required to deposit FeSi and MoS2 on SAE 4140 and AISI 304 steels is presented. To achieve this goal, the friction factor between the cotton mop and the base material was determined. The deposition process by triboadhesion is caused by the heat generated by friction between the cotton mop and the base material. During the friction, the contact between these two elements generates high instant temperatures. In the study, it was experimentally demonstrated the deposition of the material, using the tangential velocity obtained from a theoretical analysis.

  17. Characterization of gold and nickel coating on AISI 304 stainless steel for use in the fabrication of current collector plates for fuel cells; Caracterizacion de recubrimientos de oro y niquel realizados sobre acero inoxidable AISI 304 para su empleo en la fabricacion de placas colectoras de corriente para celdas de combustible

    Energy Technology Data Exchange (ETDEWEB)

    Flores Hernandez, J. Roberto [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)] e-mail: jrflores@iie.org.mx; Aguilar Gama, M. Tulio [UNAM. Facultad de Quimica, Mexico D.F. (Mexico); Cano Castillo, Ulises; Albarran, Lorena [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Olvera, J. Carlos; Orozco, German [CIDETEQ, Pedro Escobedo, Queretaro (Mexico)

    2009-09-15

    Among the different components that compose fuel cell technology (MEA, bipolar plates, seals, etc.) current collector plates play an important role in the good performance of fuel cells, since they collect all of the current generated and distribute it to the external circuit. Therefore, the most important properties that the current collector plates should have are excellent conductivity and good resistance to the corrosive conditions present in the fuel cell. This document presents results obtained during the nickel and gold electrodeposition process on AISI 304 stainless steel and the morphology and thickness of each coating, their adhesion, hardness and conductivity values. Finally, results obtained during some of the electrochemical tests performed on the coatings are shown. [Spanish] De los diferentes componentes que integran la tecnologia de celdas de combustible (MEA's, placas bipolares, sellos, etc.), las placas colectoras de corriente tienen un importante rol en el buen desempeno de la celdas de combustibles, ya que en estas placas se colecta toda la corriente generada y se distribuye al circuito externo. Debido a esto, las propiedades mas importantes que deben tener las placas colectaras de corriente son: excelente conductividad y buena resistencia a las condiciones corrosivas presentes en la celda de combustible. En este documento se presentan los resultados obtenidos en el proceso de electrodeposicion de niquel y oro sobre acero inoxidable AISI 304, asi como la morfologia y el espesor de cada recubrimiento, sus valores de adherencia, dureza y conductividad. Finalmente se muestran tambien los resultados obtenidos de algunas pruebas electroquimicas a los que fueron sometidos los recubrimientos.

  18. Literatura con mayúsculas

    Directory of Open Access Journals (Sweden)

    Cerrillo, P.

    2006-11-01

    Full Text Available En este trabajo se presenta un acercamiento alconcepto de la Literatura Infantil y Juvenil a travésde una breve visión diacrítica desde sus orígeneshasta nuestros días, subrayando los usos particularesmás característicos de esta literatura en cadaépoca (didáctico, doctrinal, proselitista…. Ademásde señalar sus coincidencias con la Literatura engeneral, se pone también de relieve sus particularidadesy características específicas, en lo que noes sino un nuevo intento de delimitar la caracterizaciónde la LIJ (contenidos, temática, estructuraliteraria, forma, ediciones… y reivindicar estaLiteratura con mayúsculas.

  19. Simultaneous Investigation of the Effect of Advanced Thermomechanical Treatment and Repetitive Cyclic Voltammetry on the Electrochemical Behavior of AISI 430 Ferritic Stainless Steel

    Science.gov (United States)

    Vafaeian, Saeed; Fattah-alhosseini, Arash; Keshavarz, Mohsen K.; Mazaheri, Yousef

    2017-02-01

    In this study, it was revealed that the electrochemical behavior of AISI 430 ferritic stainless steel can be modified and improved to a large extent by the application of repetitive cyclic voltammetry in the anodic polarization branch of the alloy. The efficiency of this method was evaluated on the basis of the alloy grain size which is of great importance in corrosion studies. In fact, a coarse grain structure versus a fine grain structure was the subject of the used surface treatment method. Coarsening and refining of the grain size were conducted through a heat treatment and an advanced thermomechanical process. On the basis of cyclic voltammetry tests and also the electrochemical tests performed after that, it was shown that cyclic voltammetry had a significant improving effect on the passive behavior of both fine- and coarse-grained samples. Moreover, superior behavior of fine-grained sample in comparison with coarse-grained one was distinguished by its smaller cyclic voltammogram loops, more noble free potentials, larger capacitive arcs in the Nyquist plots, and less charge carrier densities within the passive film.

  20. Effects of Jet Pressure on the Ground Surface Quality and CBN Wheel Wear in Grinding AISI 690 Nickel-Based Superalloy

    Science.gov (United States)

    Guitouni, Ahmed; Chaieb, Iheb; Rhouma, Amir Ben; Fredj, Nabil Ben

    2016-11-01

    Fluid application in grinding is getting attention as higher stock removal rates, higher surface integrity and longer wheel life are required. It is necessary to define proper conditions of application for meeting high productivity goals by lowering the specific grinding energy and reducing the temperature of the contact zone. The present study investigated the capacity of the jet pressure of a spot nozzle to improve the wear of a CBN wheel when grinding the AISI 690 superalloy. Grinding experiments were conducted with an emulsion-type cooling fluid delivered at pressure ranging from 0.1 to 4 MPa. Results show that the maximum stock removal, reached at 4 MPa, is 5 times the stock removal obtained at 0.1 MPa, while the grinding ratio at 4 MPa is 8 times that at 0.1 MPa, and there is a critical pressure ( P c) around 1.5 MPa corresponding to the minimum specific grinding energy. Scanning electron microscopy of the grain tips showed that the wear mechanism shifts from breaking and dislodgment at low jet pressure to micro-fracture resulting in continuous self-sharpening of the abrasive grains. By lubricating at jet pressure close to P c, there is less thermal damage due to plowing and sliding and the resulting lower loading of the abrasive grains favors the micro-fracture of grains and thus a longer wheel life.

  1. Modeling and multi-objective optimization of surface roughness and productivity in dry turning of AISI 52100 steel using (TiCN-TiN coating cermet tools

    Directory of Open Access Journals (Sweden)

    Ouahid Keblouti

    2017-01-01

    Full Text Available The present work concerns an experimental study of turning with coated cermet tools with TiCN-TiN coating layer of AISI 52100 bearing steel. The main objectives are firstly focused on the effect of cutting parameters and coating material on the performances of cutting tools. Secondly, to perform a Multi-objective optimization for minimizing surface roughness (Ra and maximizing material removal rate by desirability approach. A mathematical model was developed based on the Response Surface Methodology (RSM. ANOVA method was used to quantify the cutting parameters effects on the machining surface quality and the material removal rate. The results analysis shows that the feed rate has the most effect on the surface quality. The effect of coating layers on the surface quality is also studied. It is observed that a lower surface roughness is obtained when using PVD (TiCN-TiN coated insert when compared with uncoated tool. The values of root mean square deviation and coefficient of correlation between the theoretical and experimental data are also given in this work where the maximum calculated error is 2.65 %.

  2. Statistical analysis of AISI304 austenitic stainless steel machining using Ti(C, N/Al2O3/TiN CVD coated carbide tool

    Directory of Open Access Journals (Sweden)

    Sofiane Berkani

    2015-09-01

    Full Text Available The present research work investigated the machining of AISI304 austenitic stainless steel in terms of machining force evolution, power consumption, specific cutting force and surface roughness where a factorial experiment design and analysis of variance technique were used and several factors were evaluated for their effects on each level. The case of dry turning process was studied based on design of experiments in order to obtain empirical equations characterizing material machinability according to cutting conditions such as cutting speed, feed rate and depth of cut and the latter ones were put in relationship with the machining output variables (Ra, Fc, Kc and Pc through the response surface methodology (RSM. Results revealed that feed rate was the most preponderant factor affecting surface roughness (71.04%. However, the depth of cut affects considerably cutting force and cutting power by (60.74% and 67.11%, respectively. In addition, the specific cutting force was found affected significantly by cutting speed with a contribution of 41.43%. The quadratic model of RSM associated with response optimization technique and composite desirability was used to find optimum values of machining parameters (104.54 m/min, 0.08 mm/rev and 0.295 mm.

  3. Analysis of correlations of multiple-performance characteristics for optimization of CO2 laser nitrogen cutting of AISI 304 stainless steel

    Directory of Open Access Journals (Sweden)

    Miloš Madić

    2014-07-01

    Full Text Available The identification of laser cutting conditions for satisfying different requirements such as improving cut quality characteristics and material removal rate is of great importance. In this paper, an attempt has been made to develop mathematical models in order to relate laser cutting parameters such as the laser power, cutting speed, assist gas pressure and focus position, and cut quality characteristics such as the surface roughness, kerf width and width of heat affected zone (HAZ. A laser cutting experiment was planned as per Taguchi’s L27 orthogonal array with three levels for each of laser cutting parameters considered. 3 mm thick AISI 304 stainless steel was used as workpiece material. Mathematical models were developed using a single hidden layer artificial neural network (ANN trained with the Levenberg– Marquardt algorithm. On the basis of the developed ANN models the effects of the laser cutting parameters on the cut quality characteristics were presented. It was observed that laser cutting parameters variously affect cut quality characteristics. Also, for the range of operating conditions considered in the experiment, laser cut quality operating diagrams were shown. From these operating diagrams one can see the values of cut quality characteristics that can be achieved and subsequently select laser cutting parameter values. Furthermore, the analysis includes correlations between cut quality characteristics and material removal rate. To this aim, six trade-off operating diagrams for improving multiple responses at the same time were given.

  4. Thermally Nitrided Stainless Steels for Polymer Electrolyte Membrane Fuel Cell Bipolar Plates: Part 2: Beneficial Modification of Passive Layer on AISI446

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Heli [National Renewable Energy Laboratory (NREL); Brady, Michael P [ORNL; More, Karren Leslie [ORNL; Meyer III, Harry M [ORNL; Turner, John [National Renewable Energy Laboratory (NREL)

    2004-01-01

    Thermal nitridation of AISI446 mod-1 superferritic stainless steel for 24 h at 1100 C resulted in an adherent, inward growing surface layer based on (Cr, Fe){sub 2}N{sub 1-x} (x = 0--0.5). The layer was not continuous, and although it resulted in low interfacial contact resistance (ICR) and good corrosion resistance under simulated polymer electrolyte membrane fuel cell (PEMFC) cathodic conditions; poor corrosion resistance was observed under simulated anodic conditions. Nitridation for 2 h at 1100 C resulted in little nitrogen uptake and a tinted surface. Analysis by SEM, XPS, and AES suggested a complex heterogeneous modification of the native passive oxide film by nitrogen rather than the desired microns-thick exclusive Cr-rich nitride layer. Surprisingly, this modification resulted in both good corrosion resistance under simulated cathodic and anodic conditions and low ICR, well over an order of magnitude lower than the untreated alloy. Further, little increase in ICR was observed under passivating polarization conditions. The potential of this phenomenon for PEMFC bipolar plates is discussed.

  5. Investigation of the Mechanical Properties of AISI 316 Austenitic Stainless Steel and St 37 Low Carbon Steel Dissimilar Joint by Friction Stir Welding

    Directory of Open Access Journals (Sweden)

    A.H. Khosrovaninezhad

    2015-07-01

    Full Text Available This paper reports on the mechanical properties of the dissimilar joints between AISI 316 austenitic stainless steel and St 37 low carbon steel achieved using friction stir welding technique. The welding was carried out by means of rotational speed of 800 rpm and linear speeds of 50,100,150 mm/min. EDS and XRD techniques were employed in order to determine possible phase transformations. Tensile test, shear punch test and microhardness measurements were conducted to evaluate the mechanical properties of the joints. The results of phase investigations showed that no carbide and brittle phase were detected at the joint boundary. Also, tensile test results demonstrated that failure occurred in the St 37 base metal. According to the shear punch test, the highest ultimate shear strength and yield shear strength was achieved for the sample welded at rotational speed of 800 rpm and linear speed of 150 mm/min, while this sample showed the least elongation. In addition, the highest microhardness was measured in the stir zone of austenitic stainless steel sample welded in the above mentioned welding condition, which can be attributed to the decrease in grain size caused by recrystallization process.

  6. Influences of deposition strategies and oblique angle on properties of AISI316L stainless steel oblique thin-walled part by direct laser fabrication

    Science.gov (United States)

    Wang, Xinlin; Deng, Dewei; Qi, Meng; Zhang, Hongchao

    2016-06-01

    Direct laser fabrication (DLF) developed from laser cladding and rapid prototyping technique has been widely used to fabricate thin-walled parts exhibiting more functions without expending weight and size. Oblique thin-walled parts accompanied with inhomogeneous mechanical properties are common in application. In the present study, a series of AISI316L stainless steel oblique thin-walled parts are successfully produced by DLF, in addition, deposition strategies, microstructure, and mechanical property of the oblique thin-walled parts are investigated. The results show that parallel deposition way is more valuable to fabricate oblique thin-walled part than oblique deposition way, because of the more remarkable properties. The hardness of high side initially increases until the distance to the substrate reaches about 25 mm, and then decreases with the increase of the deposition height. Oblique angle has a positive effect on the tensile property but a negative effect on microstructure, hardness and elongation due to the more tempering time. The maximum average ultimate tensile strength (UTS) and elongation are presented 744.3 MPa and 13.5% when the angle between tensile loading direction and horizontal direction is 45° and 90°, respectively.

  7. Simultaneous Investigation of the Effect of Advanced Thermomechanical Treatment and Repetitive Cyclic Voltammetry on the Electrochemical Behavior of AISI 430 Ferritic Stainless Steel

    Science.gov (United States)

    Vafaeian, Saeed; Fattah-alhosseini, Arash; Keshavarz, Mohsen K.; Mazaheri, Yousef

    2017-01-01

    In this study, it was revealed that the electrochemical behavior of AISI 430 ferritic stainless steel can be modified and improved to a large extent by the application of repetitive cyclic voltammetry in the anodic polarization branch of the alloy. The efficiency of this method was evaluated on the basis of the alloy grain size which is of great importance in corrosion studies. In fact, a coarse grain structure versus a fine grain structure was the subject of the used surface treatment method. Coarsening and refining of the grain size were conducted through a heat treatment and an advanced thermomechanical process. On the basis of cyclic voltammetry tests and also the electrochemical tests performed after that, it was shown that cyclic voltammetry had a significant improving effect on the passive behavior of both fine- and coarse-grained samples. Moreover, superior behavior of fine-grained sample in comparison with coarse-grained one was distinguished by its smaller cyclic voltammogram loops, more noble free potentials, larger capacitive arcs in the Nyquist plots, and less charge carrier densities within the passive film.

  8. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: crazyfim@gmail.com [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); López-Morelos, V.H., E-mail: vhlopez@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); García-Hernández, R., E-mail: rgarcia@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); Dzib-Pérez, L., E-mail: luirdzib@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); García-Ochoa, E.M., E-mail: emgarcia@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); González-Sánchez, J., E-mail: jagonzal@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico)

    2014-12-01

    Highlights: • Electromagnetic interaction in welding improved localised corrosion resistance. • Electromagnetic interaction in welding enhanced γ/δ phase balance of DuplexSS. • Welding under Electromagnetic interaction repress formation and growth of detrimental phases. • Welds made with gas protection (2% O{sub 2} + 98% Ar) have better microstructural evolution during welding. - Abstract: The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O{sub 2} (M1) and 97% Ar + 3% N{sub 2} (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  9. Formation of abrasion-resistant coatings of the AlSiFe{sub x}Mny intermetallic compound type on the AISI 304L alloy

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Peralez, L. G.; Flores-Valdes, A.; Salinas-Rodriguez, A.; Ochoa-Palacios, R. M.; Toscano-giles, J. A.; Torres-Torres, J.

    2016-05-01

    The α-Al{sub 9}FeMnSi and α-Al{sub 9}FeMn{sub 2}Si intermetallics formed by reactive sintering of Al, Si, Mn, Fe, Cr and Ni powders have been used in AISI 304L steels to enhance microhardness. Processing variables of the reactive sintering treatment were temperature (600, 650, 700, 750 and 800 degree centigrade), pressure (5, 10 y 20 MPa) and holding time (3600, 5400 y 7200 seconds). Experimental results show that temperature is the most important variable affecting the substrate/coating formation, while pressure does not appear to have a significant effect. The results show the optimum conditions of the reactive sintering that favor the substrate/coating formation are 800 degree centigrade, 20 MPa and 7200 seconds. Under these conditions, the reaction zone between the substrate and coating is more compacted and well-adhered, with a microhardness of 1300 Vickers. The results of SEM and X-Ray diffraction confirmed the formation of β-Al{sub 9}FeMnSi and β-Al{sub 9}FeMn{sub 2}Si intermetallics in the substrate/coating interface as well as the presence of Cr and Ni, indicating diffusion of these two elements from the substrate to the interface. (Author)

  10. Multi-Objective Optimization In Turning Of Cylindrical Bars Of AISI 1045 Steel Through Taguchi’s Method And Utility Concept

    Directory of Open Access Journals (Sweden)

    AJAY MISHRA

    2013-09-01

    Full Text Available The Taguchi’s approach is a quality design technique whose application in determining the optimal settings of controllable parameters in various single-objective optimization have been recently exploited. But most of the product or processes have several quality characteristics of interest. This paper investigated the multi-objective optimization of the turning process of AISI 1045 steel cylindrical bars to yield the minimum tool flank wear width, surface roughness and roundness through the combination of Taguchi method and Utility concept. Nine experimental runs based on Taguchi’s L9 orthogonal array were performed and signal to noise (S/N ratios, analysis of variance (ANOVA and utility values were used with cutting speed, feed rate and depth of cut as turning process parameters and with tool flank wear width, surface roughness and roundness as response variables. The optimal values obtained during the study using the multi-objective optimization with the help of Taguchi method and utility concept have been validated by confirmation experiments.

  11. Microstructure and Corrosion Properties of AlCoCrFeNi High Entropy Alloy Coatings Deposited on AISI 1045 Steel by the Electrospark Process

    Science.gov (United States)

    Li, Q. H.; Yue, T. M.; Guo, Z. N.; Lin, X.

    2013-04-01

    Electrospark deposition (ESD) was employed to clad the AlCoCrFeNi high-entropy alloy (HEA) on AISI 1045 carbon steel. The relationship between the microstructure and corrosion properties of the HEA-coated specimens was studied and compared with that of the copper-molded cast HEA material. Two major microstructural differences were found between the cast HEA material and the HEA coatings. First, the cast material comprises both columnar and equiaxed crystals with a columnar-to-equiaxed transition (CET), whereas the HEA coatings consist of an entirely columnar crystal structure. The CET phenomenon was analyzed based on Hunt's criterion. Second, unlike the cast HEA material, there was no obvious Cr-rich interdendritic segregation and nano-sized precipitate distributed within the dendrites of the HEA coating. With regard to corrosion properties, the corrosion current of the HEA-coated specimen was significantly lower than for the 1045 steel and the cast HEA material. This was attributed to the ESD specimen having a relatively high Cr oxide and Al oxide content at the surface. Moreover, for the ESD specimen, the absence of Cr-rich interdendritic phase and second-phase precipitation resulted in a relatively uniform corrosion attack, which is different from the severe galvanic corrosion attack that occurred in the cast specimen.

  12. Effect of prior cold work on the degree of sensitisation of welded joints of AISI 316L austenitic stainless steel studied by using an electrochemical minicell

    Energy Technology Data Exchange (ETDEWEB)

    De Tiedra, Pilar [Ciencia de los Materiales e Ingenieria Metalurgica, Departamento CMeIM/EGI/ICGF/IM/IPF, Universidad de Valladolid, Escuela de Ingenierias Industriales, Paseo del Cauce 59, Valladolid 47011 (Spain); Martin, Oscar, E-mail: oml@eis.uva.es [Ciencia de los Materiales e Ingenieria Metalurgica, Departamento CMeIM/EGI/ICGF/IM/IPF, Universidad de Valladolid, Escuela de Ingenierias Industriales, Paseo del Cauce 59, Valladolid 47011 (Spain); Garcia, Cristina; Martin, Fernando; Lopez, Manuel [Ciencia de los Materiales e Ingenieria Metalurgica, Departamento CMeIM/EGI/ICGF/IM/IPF, Universidad de Valladolid, Escuela de Ingenierias Industriales, Paseo del Cauce 59, Valladolid 47011 (Spain)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer Double loop shows greater sensitivity to interdendritic corrosion than single loop. Black-Right-Pointing-Pointer Fusion line sensitisation is lower than that of weld metal for all prior cold works. Black-Right-Pointing-Pointer Heat affected zone sensitisation is maximum at a prior cold work of 10%. Black-Right-Pointing-Pointer Heat affected zone sensitisation Much-Less-Than base material sensitisation for a prior cold work of 20%. - Abstract: This work aims to assess the effect of prior cold work on the degree of sensitisation of each of the four welding zones of welded joints of AISI 316L subjected to post-welding sensitisation. Electrochemical potentiokinetic reactivation and double loop electrochemical potentiokinetic reactivation tests are performed on each of the four zones by using a small-scale electrochemical cell (minicell). The results show that the degree of sensitisation of heat affected zone, which achieves its maximum at a prior cold work level of 10%, is significantly lower than that of base material for a prior cold work of 20%.

  13. Effects of Jet Pressure on the Ground Surface Quality and CBN Wheel Wear in Grinding AISI 690 Nickel-Based Superalloy

    Science.gov (United States)

    Guitouni, Ahmed; Chaieb, Iheb; Rhouma, Amir Ben; Fredj, Nabil Ben

    2016-09-01

    Fluid application in grinding is getting attention as higher stock removal rates, higher surface integrity and longer wheel life are required. It is necessary to define proper conditions of application for meeting high productivity goals by lowering the specific grinding energy and reducing the temperature of the contact zone. The present study investigated the capacity of the jet pressure of a spot nozzle to improve the wear of a CBN wheel when grinding the AISI 690 superalloy. Grinding experiments were conducted with an emulsion-type cooling fluid delivered at pressure ranging from 0.1 to 4 MPa. Results show that the maximum stock removal, reached at 4 MPa, is 5 times the stock removal obtained at 0.1 MPa, while the grinding ratio at 4 MPa is 8 times that at 0.1 MPa, and there is a critical pressure (P c) around 1.5 MPa corresponding to the minimum specific grinding energy. Scanning electron microscopy of the grain tips showed that the wear mechanism shifts from breaking and dislodgment at low jet pressure to micro-fracture resulting in continuous self-sharpening of the abrasive grains. By lubricating at jet pressure close to P c, there is less thermal damage due to plowing and sliding and the resulting lower loading of the abrasive grains favors the micro-fracture of grains and thus a longer wheel life.

  14. Microstructural Characterization and Wear Behavior of Nano-Boride Dispersed Coating on AISI 304 Stainless Steel by Hybrid High Velocity Oxy-Fuel Spraying Laser Surface Melting

    Science.gov (United States)

    Sharma, Prashant; Majumdar, Jyotsna Dutta

    2015-07-01

    The current study concerns the detailed microstructural characterization and investigation of wear behavior of nano-boride dispersed coating developed on AISI 304 stainless steel by high velocity oxy-fuel spray deposition of nickel-based alloy and subsequent laser melting. There is a significant refinement and homogenization of microstructure with improvement in microhardness due to laser surface melting (1200 VHN as compared to 945 VHN of as-sprayed and 250 VHN of as-received substrate). The high temperature phase stability of the as-coated and laser melted surface has been studied by differential scanning calorimeter followed by detailed phase analysis at room and elevated temperature. There is a significant improvement in wear resistance of laser melted surface as compared to as-sprayed and the as-received one due to increased hardness and reduced coefficient of friction. The mechanism of wear has been investigated in details. Corrosion resistance of the coating in a 3.56 wt pct NaCl solution is significantly improved (4.43 E-2 mm/year as compared to 5 E-1 mm/year of as-sprayed and 1.66 mm/year of as-received substrate) due to laser surface melting as compared to as-sprayed surface.

  15. Effect of Welding Current and Time on the Microstructure, Mechanical Characterizations, and Fracture Studies of Resistance Spot Welding Joints of AISI 316L Austenitic Stainless Steel

    Science.gov (United States)

    Kianersi, Danial; Mostafaei, Amir; Mohammadi, Javad

    2014-09-01

    This article aims at investigating the effect of welding parameters, namely, welding current and welding time, on resistance spot welding (RSW) of the AISI 316L austenitic stainless steel sheets. The influence of welding current and welding time on the weld properties including the weld nugget diameter or fusion zone, tensile-shear load-bearing capacity of welded materials, failure modes, energy absorption, and microstructure of welded nuggets was precisely considered. Microstructural studies and mechanical properties showed that the region between interfacial to pullout mode transition and expulsion limit is defined as the optimum welding condition. Electron microscopic studies indicated different types of delta ferrite in welded nuggets including skeletal, acicular, and lathy delta ferrite morphologies as a result of nonequilibrium phases, which can be attributed to a fast cooling rate in the RSW process. These morphologies were explained based on Shaeffler, WRC-1992, and pseudo-binary phase diagrams. The optimum microstructure and mechanical properties were achieved with 8-kA welding current and 4-cycle welding time in which maximum tensile-shear load-bearing capacity or peak load of the welded materials was obtained at 8070 N, and the failure mode took place as button pullout with tearing from the base metal. Finally, fracture surface studies indicated that elongated dimples appeared on the surface as a result of ductile fracture in the sample welded in the optimum welding condition.

  16. Evaluation of the Synergistic Effect of Erosion-Corrosion on AISI 4330 Steel in Saline-Sand Multiphase Flow by Electrochemical and Gravimetric Techniques

    Directory of Open Access Journals (Sweden)

    Dario Yesid Peña Ballesteros

    2016-01-01

    Full Text Available The synergistic effects of fluid flow, sand particles, and solution pH on erosion-corrosion of AISI 4330 steel alloy in saline-sand medium were studied through a rotating cylinder electrode (RCE system by weight-loss and electrochemical measurements. The worn surface was analyzed by X-ray diffraction (XRD and scanning electron microscopy (SEM. Results show that, under all the test conditions assessed, the passivity of the steel alloy could not be maintained; as a result, an activation mechanism dominates the corrosion process of steel alloy. Furthermore, the potentiodynamic curves show that, with the increasing of the electrode flow rate and particle size, the anodic current density increased, which is due to deterioration of the electrode by the impacting slurry. Although the increase of particle size affects the anodic current density, the effect of particle size does not cause a significant change in the polarization behavior of the steel electrode. The electrochemical impedance and potentiodynamic curves suggest that erosion-corrosion phenomenon of the ASISI 4330 steel is under mixed control of mass transport and charge transfer. The inductive loops formed in the impedance plots are representative of an increase in roughness of the electrode caused by the particles impacting at the surface. The change in the passivity of the steel alloy as the pH is altered plays an important role in the corrosion rate.

  17. Impact of the surface roughness of AISI 316L stainless steel on biofilm adhesion in a seawater-cooled tubular heat exchanger-condenser.

    Science.gov (United States)

    García, Sergio; Trueba, Alfredo; Vega, Luis M; Madariaga, Ernesto

    2016-11-01

    The present study evaluated biofilm growth in AISI 316L stainless steel tubes for seawater-cooled exchanger-condensers that had four different arithmetic mean surface roughness values ranging from 0.14 μm to 1.2 μm. The results of fluid frictional resistance and heat transfer resistance regarding biofilm formation in the roughest surface showed increases of 28.2% and 19.1% respectively, compared with the smoothest surface. The biofilm thickness taken at the end of the experiment showed variations of up to 74% between the smoothest and roughest surfaces. The thermal efficiency of the heat transfer process in the tube with the roughest surface was 17.4% greater than that in the tube with the smoothest surface. The results suggest that the finish of the inner surfaces of the tubes in heat exchanger-condensers is critical for improving energy efficiency and avoiding biofilm adhesion. This may be utilised to reduce biofilm adhesion and growth in the design of heat exchanger-condensers.

  18. Influence of Surface Position along the Working Range of Conoscopic Holography Sensors on Dimensional Verification of AISI 316 Wire EDM Machined Surfaces

    Directory of Open Access Journals (Sweden)

    Pedro Fernández

    2014-03-01

    Full Text Available Conoscopic holography (CH is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F and power (P until the quality indicators Signal-to-Noise Ratio (SNR and signal envelope (Total meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR. Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP on a CMM.

  19. Microstructure and Wear Properties of FeCrC, FeW and Feti Modified Iron Based Alloy Coating Deposited by PTA Process on AISI 430 Steel

    Directory of Open Access Journals (Sweden)

    Teker T.

    2014-10-01

    Full Text Available The plasma transferred arc (PTA process was used for developing wear resistance of AISI 430 steel substrate. Appropriate quantities of FeCrC, FeW and FeTi powders were combined to create conditions that synthesized M7C3 particles into reinforced Fe-based composite surface coating. The phase transformations on new created coated surfaces were comprehensively examined by using a combination of scanning electron microscopy (SEM, microanalysis by energy dispersive spectrometry (EDS, X-Ray diffraction (XRD, microhardness and abrasive wear tests. The microstructure studies of the superficial layers of the coating revealed presence of a mixture of the dendritic phase structure of austenite (γ and fine eutectic M7C3 carbides. The results show that; the concentrations of the elements (Cr, W, Ti added as ferroalloys, the size of dendrites formed in the coated surface, the change of hardness of the coated surfaces, the carbide volume rate and thickness of the coating changed by the variation of the processing parameters (ratio of reinforcement particulates and heat input.

  20. IN SITU OBSERVATION OF GROWTH BEHAVIOR AND MORPHOLOGY OF DELTA-FERRITE AS FUNCTION OF SOLIDIFICATION RATE IN AN AISI304 STAINLESS STEEL

    Institute of Scientific and Technical Information of China (English)

    G.F. Liang; C.Q. Wan; J.C. Wu; G.M. Zhu; Y. Yu; Y. Fang

    2006-01-01

    It was presented the in situ observation of growth behavior and morphology of delta-ferrite as a function of solidification rate in an AISI304 stainless steel. The specimens have been solidified and observed using confocal scanning laser microscopy ( CSLM). The δ-phase always appears like cells on the sample surface when critical supercooling occurs, during which the L→δtransformation starts. The solid-liquid (S-L) interface is found to be finger shaped and has no faceted shape. Γ phase appears among δ grains due to partitioning of Ni into the melt during solidification, when solidification rate is higher. The mergence of observed δ cells is possible for the steel sample cooled at 7.5℃/min. The formation of dendrites can be observed on the free surface of the steel sample cooled at 150℃/min. The size of solidified delta grains decreases from 120 to 20-80μm, and the volume fraction of solidified austenite increases with increase in solidification rate from 7.5 to 150℃/min. The relation between the tip radius of δ cell and its growth rate is deduced, and the results agree with the experimental values.