WorldWideScience

Sample records for resistant steels produced

  1. Hardness and Wear Resistance of TiC-Fe-Cr Locally Reinforcement Produced in Cast Steel

    Directory of Open Access Journals (Sweden)

    Olejnik E.

    2016-06-01

    Full Text Available In order to increase wear resistance cast steel casting the TiC-Fe-Cr type composite zones were fabricated. These zones were obtained by means of in situ synthesis of substrates of the reaction TiC with a moderator of a chemical composition of white cast iron with nickel of the Ni-Hard type 4. The synthesis was carried out directly in the mould cavity. The moderator was applied to control the reactive infiltration occurring during the TiC synthesis. The microstructure of composite zones was investigated by electron scanning microscopy, using the backscattered electron mode. The structure of composite zones was verified by the X-ray diffraction method. The hardness of composite zones, cast steel base alloy and the reference samples such as white chromium cast iron with 14 % Cr and 20 % Cr, manganese cast steel 18 % Mn was measured by Vickers test. The wear resistance of the composite zone and the reference samples examined by ball-on-disc wear test. Dimensionally stable composite zones were obtained containing submicron sizes TiC particles uniformly distributed in the matrix. The macro and microstructure of the composite zone ensured three times hardness increase in comparison to the cast steel base alloy and one and a half times increase in comparison to the white chromium cast iron 20 % Cr. Finally ball-on-disc wear rate of the composite zone was five times lower than chromium white cast iron containing 20 % Cr.

  2. HEAT RESISTANCE OF GRAPHITIZED STEEL

    Directory of Open Access Journals (Sweden)

    V. O. Savchenko

    2014-06-01

    Full Text Available Purpose. The investigation of temperature dependences of steels' mechanical properties and heat resistance under conditions of thermal cyclic loads. It's necessary to determine the mechanical properties and heat resistance indices of graphitized steels and cast iron VCh400 within the temperature range of 20…800°С. Methodology. Graphitized steels of the following chemical composition (mass %: 0.61…1.04C; 1.19…1.59%Si; 0.32…0.37%Mn; 0.12…0.17%Al; 0.008…0.014%S and 0.016…0.025%Р have been heat-treated according to the mode: heating up to 810°С – holding for 2 hours; cooling down to 680°С – holding for 2 hours with further cooling using the furnace in order to provide the ferrite-pearlite metallic base with graphite inclusions. In order to determine heat resistance indices (heat stresses index K and the material's resistance criterion at thermal cyclic load C the indices of graphitized steels' and cast irons' mechanical properties in the temperature range of 20…800°С have been investigated. Findings. It has been established that as a result of lower carbon content and smaller quantity of graphite inclusions, graphitized steel exceeds such indices of nodular cast iron VCh400 as: tensile strength and plasticity at room and high temperatures, and also heat resistance criteria K and C. This steel can be used to manufacture articles operating under conditions of thermal cyclic loads. Originality. Tensile strength and percent elongation of graphitized steels within the temperature range of 20…800°С have been determined. Calculations of heat resistance criteria to the heat stresses index K and the material's resistance criterion at thermal cyclic loads C within the temperature range 20…800°С in comparison with nodular cast iron of VCh400 grade have been carried out. Practical value. The expediency of using graphitized steel for manufacturing of articles operating under conditions of thermal cyclic loads has been shown.

  3. Electrical resistance tomography from measurements inside a steel cased borehole

    Science.gov (United States)

    Daily, William D.; Schenkel, Clifford; Ramirez, Abelardo L.

    2000-01-01

    Electrical resistance tomography (ERT) produced from measurements taken inside a steel cased borehole. A tomographic inversion of electrical resistance measurements made within a steel casing was then made for the purpose of imaging the electrical resistivity distribution in the formation remotely from the borehole. The ERT method involves combining electrical resistance measurements made inside a steel casing of a borehole to determine the electrical resistivity in the formation adjacent to the borehole; and the inversion of electrical resistance measurements made from a borehole not cased with an electrically conducting casing to determine the electrical resistivity distribution remotely from a borehole. It has been demonstrated that by using these combined techniques, highly accurate current injection and voltage measurements, made at appropriate points within the casing, can be tomographically inverted to yield useful information outside the borehole casing.

  4. Laser borided composite layer produced on austenitic 316L steel

    Directory of Open Access Journals (Sweden)

    Mikołajczak Daria

    2016-12-01

    Full Text Available Abstract Austenitic 316L steel is well-known for its good resistance to corrosion and oxidation. Therefore, this material is often used wherever corrosive media or high temperatures are to be expected. The main drawback of this material is very low hardness and low resistance to mechanical wear. In this study, the laser boriding was used in order to improve the wear behavior of this material. As a consequence, a composite surface layer was produced. The microstructure of laser-borided steel was characterized by only two zones: re-melted zone and base material. In the re-melted zone, a composite microstructure, consisting of hard ceramic phases (borides and a soft austenitic matrix, was observed. A significant increase in hardness and wear resistance of such a layer was obtained.

  5. Electrical resistance tomography using steel cased boreholes as electrodes

    Science.gov (United States)

    Daily, William D.; Ramirez, Abelardo L.

    1999-01-01

    An electrical resistance tomography method using steel cased boreholes as electrodes. The method enables mapping the electrical resistivity distribution in the subsurface from measurements of electrical potential caused by electrical currents injected into an array of electrodes in the subsurface. By use of current injection and potential measurement electrodes to generate data about the subsurface resistivity distribution, which data is then used in an inverse calculation, a model of the electrical resistivity distribution can be obtained. The inverse model may be constrained by independent data to better define an inverse solution. The method utilizes pairs of electrically conductive (steel) borehole casings as current injection electrodes and as potential measurement electrodes. The greater the number of steel cased boreholes in an array, the greater the amount of data is obtained. The steel cased boreholes may be utilized for either current injection or potential measurement electrodes. The subsurface model produced by this method can be 2 or 3 dimensional in resistivity depending on the detail desired in the calculated resistivity distribution and the amount of data to constain the models.

  6. Towards self-healing creep resistant steels

    NARCIS (Netherlands)

    Van der Zwaag, S.; Zhang, S.; Fang, H.; Bruck, E.; Van Dijk, N.H.

    2016-01-01

    We report the main findings of our work on the behaviour of binary Fe-Cu and Fe-Au model alloys designed to explore routes to create new creep resistant steels having an in-built ability to autonomously fill creep induced porosity at grain boundaries. The alloying elements were selected on the basis

  7. Microstructures and properties of low-alloy fire resistant steel

    Indian Academy of Sciences (India)

    Unknown

    Fire resistant steel; thermomechanical processing; microstructure; strength; thermal conductivity. 1. Introduction. Steel structures using mild steel in fire sensitive areas are protected from fire by providing fire resistant coating or insulation. This adds to the constructional cost. The problem with unprotected carbon–manganese ...

  8. Pitting corrosion resistant austenite stainless steel

    Science.gov (United States)

    van Rooyen, D.; Bandy, R.

    A pitting corrosion resistant austenite stainless steel comprises 17 to 28 wt. % chromium, 15 to 26 wt. % nickel, 5 to 8 wt. % molybdenum, and 0.3 to 0.5 wt. % nitrogen, the balance being iron, unavoidable impurities, minor additions made in the normal course of melting and casting alloys of this type, and may optionally include up to 10 wt. % of manganese, up to 5 wt. % of silicon, and up to 0.08 wt. % of carbon.

  9. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2015-11-13

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6 carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  10. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2017-01-31

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, copper, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  11. Research and development of weathering resistant bridge steel of Shougang

    Science.gov (United States)

    Yang, Yongda; Wang, Yanfeng; Huang, Leqing; Di, Guobiao; Ma, Changwen; Ma, Qingshen

    2017-09-01

    To introduce the composition design and mechanical properties and microstructure of the weathering bridge steel which would be used for bridge of Guanting reservoir. We adopt cyclic immersion corrosion test to study corrosion resistance difference of weathering bridge steel and common bridge steel. At the same corrosion time, the weight loss and corrosion rate of weathering bridge steel are lower than the common bridge steel's. Testing phase composition of rust layer by X-ray diffraction, two kinds of test steel's rust layer is mainly composed of Goethite and Fe3O4 and Fe2O3. At the same corrosion time, the percentage composition of goethite in rust layer of weathering bridge steel are significantly higher than common bridge steel's, the higher goethite content is, the compacter rust layer structure is. The compact rust layer would prevent the water and air passing the rust layer, and then preventing the further corrosion reaction, improving the corrosion resistance performance of weathering bridge steel.

  12. Radiation resistant austenitic stainless steel alloys

    Science.gov (United States)

    Maziasz, P.J.; Braski, D.N.; Rowcliffe, A.F.

    1987-02-11

    An austenitic stainless steel alloy, with improved resistance to radiation-induced swelling and helium embrittlement, and improved resistance to thermal creep at high temperatures, consisting essentially of, by weight percent: from 16 to 18% nickel; from 13 to 17% chromium; from 2 to 3% molybdenum; from 1.5 to 2.5% manganese; from 0.01 to 0.5% silicon; from 0.2 to 0.4% titanium; from 0.1 to 0.2% niobium; from 0.1 to 0.6% vanadium; from 0.06 to 0.12% carbon; from 0.01 to 0.03% nitrogen; from 0.03 to 0.08% phosphorus; from 0.005 to 0.01% boron; and the balance iron, and wherein the alloy may be thermomechanically treated to enhance physical and mechanical properties. 4 figs.

  13. Resistance of Some Steels to Stress Corrosion Cracking

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1982-01-01

    Evaluations of stress-corrosion cracking resistance of five high-strength low-alloy steels described in report now available. Steels were heat-treated to various tensile strengths and found to be highly resistant to stress-corrosion cracking.

  14. Micro-Abrasion Wear Resistance of Borided 316L Stainless Steel and AISI 1018 Steel

    Science.gov (United States)

    Reséndiz-Calderon, C. D.; Rodríguez-Castro, G. A.; Meneses-Amador, A.; Campos-Silva, I. E.; Andraca-Adame, J.; Palomar-Pardavé, M. E.; Gallardo-Hernández, E. A.

    2017-11-01

    The 316L stainless steel has high corrosion resistance but low tribological performance. In different industrial sectors (biomedical, chemical, petrochemical, and nuclear engineering), improvement upon wear resistance of 316L stainless steel components using accessible and inexpensive methods is critical. The AISI 1018 steel is widely used in industry, but its tribological performance is not the best among steels. Therefore, in this study the behavior of the borided 316L stainless steel and 1018 steel is evaluated under micro-abrasion wear. The boriding was carried out at 1223 K over 6 h of exposure time, resulting in a biphase layer composed of FeB/Fe2B phases. In order to evaluate Fe2B phase with no influence from FeB phase, AISI 1018 steel samples were borided at 1273 K for over 20 min and then diffusion annealed at 1273 K over 2 h to obtain a Fe2B mono-phase layer. Micro-abrasion wear resistance was evaluated by a commercial micro-abrasion testing rig using a mix of F-1200 SiC particles with deionized water as abrasive slurry. The obtained wear rates for FeB and Fe2B phases and for the 316L stainless steel were compared. Wear resistance of 316L stainless steel increases after boriding. The wear mechanisms for both phases and for the stainless steel were identified. Also, transient conditions for rolling and grooving abrasion were determined for the FeB and Fe2B phases.

  15. Micro-Abrasion Wear Resistance of Borided 316L Stainless Steel and AISI 1018 Steel

    Science.gov (United States)

    Reséndiz-Calderon, C. D.; Rodríguez-Castro, G. A.; Meneses-Amador, A.; Campos-Silva, I. E.; Andraca-Adame, J.; Palomar-Pardavé, M. E.; Gallardo-Hernández, E. A.

    2017-10-01

    The 316L stainless steel has high corrosion resistance but low tribological performance. In different industrial sectors (biomedical, chemical, petrochemical, and nuclear engineering), improvement upon wear resistance of 316L stainless steel components using accessible and inexpensive methods is critical. The AISI 1018 steel is widely used in industry, but its tribological performance is not the best among steels. Therefore, in this study the behavior of the borided 316L stainless steel and 1018 steel is evaluated under micro-abrasion wear. The boriding was carried out at 1223 K over 6 h of exposure time, resulting in a biphase layer composed of FeB/Fe2B phases. In order to evaluate Fe2B phase with no influence from FeB phase, AISI 1018 steel samples were borided at 1273 K for over 20 min and then diffusion annealed at 1273 K over 2 h to obtain a Fe2B mono-phase layer. Micro-abrasion wear resistance was evaluated by a commercial micro-abrasion testing rig using a mix of F-1200 SiC particles with deionized water as abrasive slurry. The obtained wear rates for FeB and Fe2B phases and for the 316L stainless steel were compared. Wear resistance of 316L stainless steel increases after boriding. The wear mechanisms for both phases and for the stainless steel were identified. Also, transient conditions for rolling and grooving abrasion were determined for the FeB and Fe2B phases.

  16. The comparison of frictional resistance in titanium, self-ligating stainless steel, and stainless steel brackets using stainless steel and TMA archwires: An in vitro study

    OpenAIRE

    Khalid, Syed Altaf; Kumar, Vadivel; Jayaram, Prithviraj

    2012-01-01

    Aim: The aim of the study was to compare the frictional resistance of titanium, self-ligating stainless steel, and conventional stainless steel brackets, using stainless steel and titanium molybdenum alloy (TMA) archwires. Materials and Methods: We compared the frictional resistance in 0.018 slot and 0.022 slot of the three brackets - titanium, self-ligating stainless steel, and conventional stainless steel - using stainless steel archwires and TMA archwires. An in vitro study of simulated ca...

  17. Influence of femtosecond laser produced nanostructures on biofilm growth on steel

    Science.gov (United States)

    Epperlein, Nadja; Menzel, Friederike; Schwibbert, Karin; Koter, Robert; Bonse, Jörn; Sameith, Janin; Krüger, Jörg; Toepel, Jörg

    2017-10-01

    Biofilm formation poses high risks in multiple industrial and medical settings. However, the robust nature of biofilms makes them also attractive for industrial applications where cell biocatalysts are increasingly in use. Since tailoring material properties that affect bacterial growth or its inhibition is gaining attention, here we focus on the effects of femtosecond laser produced nanostructures on bacterial adhesion. Large area periodic surface structures were generated on steel surfaces using 30-fs laser pulses at 790 nm wavelength. Two types of steel exhibiting a different corrosion resistance were used, i.e., a plain structural steel (corrodible) and a stainless steel (resistant to corrosion). Homogeneous fields of laser-induced periodic surface structures (LIPSS) were realized utilizing laser fluences close to the ablation threshold while scanning the sample under the focused laser beam in a multi-pulse regime. The nanostructures were characterized with optical and scanning electron microscopy. For each type of steel, more than ten identical samples were laser-processed. Subsequently, the samples were subjected to microbial adhesion tests. Bacteria of different shape and adhesion behavior (Escherichia coli and Staphylococcus aureus) were exposed to laser structures and to polished reference surfaces. Our results indicate that E. coli preferentially avoids adhesion to the LIPSS-covered areas, whereas S. aureus favors these areas for colonization.

  18. Coated steel rebar for enhanced concrete-steel bond strength and corrosion resistance.

    Science.gov (United States)

    2010-10-01

    This report summarizes the findings and recommendations on the use of enamel coating in reinforced concrete structures both for bond strength and : corrosion resistance of steel rebar. Extensive laboratory tests were conducted to characterize the pro...

  19. Development status und future possibilities for martensitic creep resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Hald, J. [Technical Univ. Denmark, Lyngby (Denmark). Dept. of Mechanical Engineering

    2010-07-01

    In the last four decades new stronger modified 9%Cr martensitic creep resistant steels have been introduced in power plants, which has enabled increases in maximum achievable steam conditions from the previous 250 bar and 540-560 C up to the values of 300 bar and 600-620 C currently being introduced all over the world. In order to further increase the steam parameters of steel based power plants up to a target value of 650 C/325 bar it is necessary to double the creep strength of the martensitic steels. At the same time the resistance against steam oxidation must be improved by an increase of the chromium content in the steels from 9% to 12%. However, so far all attempts to make stronger 12%Cr steels have led to breakdowns in long-term creep strength. Significant progress has been achieved in the understanding of microstructure stability of the martensitic 9-12%Cr steels: Observed microstructure instabilities in 11-12%Cr steels are explained by Z-phase precipitation, which dissolves fine MN nitrides. Improved understanding of effects of B and N on long-term creep properties has formed the basis of a series of new stronger 9%Cr test alloys with improved creep strength. In parallel 9%Cr test steels with low C content show very promising behavior in long-term tests. However, the 9%Cr steels must be surface coated to protect against steam oxidation at high temperature applications above 620%C. A possibility to use fine Z-phases for strengthening of the martensitic steels has been identified, and this opens a new pathway for development of stable strong 12%Cr steels. There are still good prospects for the realization of a 325 bar / 650 C steam power plant all based on steel. (orig.)

  20. A technique for predicting steel corrosion resistance

    Science.gov (United States)

    Novikov, V. F.; Sokolov, R. A.; Neradovskiy, D. F.; Muratov, K. R.

    2018-01-01

    Research works were carried out to develop a technique with the aim to increase the lifetime of steel items used in corrosive media. The possibility to monitor corrosion parameters of steel samples is analyzed on the basis of magnetic properties obtained by means of a magnetic structuroscope DIUS-1.15M designed by the Institute of Metal Physics of the Ural Branch of the Russian Academy of Sciences (IMP UB RAS).

  1. Study of Stainless Steel Resistance in Conditions of Tribocorrosion Wear

    Directory of Open Access Journals (Sweden)

    Goran Rozing

    2015-07-01

    Full Text Available Analyzed was the influence of tribocorrosion wear due to effects of fatty acids present in the processed medium. The analysis was conducted on samples made of two austenitic and two martensitic stainless steels. Austenitic steels were tested in their nitrided state and martensitic in their induction hardened state. Conducted were laboratory tests of corrosion resistance of samples, analysis of the microstructure and hardness. To see how the applied processes for modifying the surface of stainless steels behave in realistic conditions, it was conducted the examination of samples/parts of a sunflower cake chain conveyer. Based on the comparison of results obtained in the laboratory and in real conditions, it was estimated that steels AISI 420 and AISI 431 with induction hardened surfaces have a satisfactory resistance to abrasive-adhesive wear in the presence of fatty acids.

  2. Creep Resistance of VM12 Steel

    Directory of Open Access Journals (Sweden)

    Zieliński A.

    2016-09-01

    Full Text Available This article presents selected material characteristics of VM12 steel used for elements of boilers with super- and ultra-critical steam parameters. In particular, abridged and long-term creep tests with and without elongation measurement during testing and investigations of microstructural changes due to long-term impact of temperature and stress were carried out. The practical aspect of the use of creep test results in forecasting the durability of materials operating under creep conditions was presented. The characteristics of steels with regard to creep tests developed in this paper are used in assessment of changes in functional properties of the material of elements operating under creep conditions.

  3. Observations on the electrical resistivity of steel fibre reinforced concrete

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe; Geiker, Mette Rica; Edvardsen, Carola

    2014-01-01

    Steel fibre reinforced concrete (SFRC) is in many ways a well-known construction material, and its use has gradually increased over the last decades. The mechanical properties of SFRC are well described based on the theories of fracture mechanics. However, knowledge on other material properties......, including the electrical resistivity, is sparse. Among others, the electrical resistivity of concrete has an effect on the corrosion process of possible embedded bar reinforcement and transfer of stray current. The present paper provides experimental results concerning the influence of the fibre volume...... the observed correlation between the fibre volume fraction and the electrical resistivity of the composite (the SFRC) for conductive fibres and moisture saturated concrete. This indicates that the steel fibres were conducting when measuring the electrical resistivity by AC at 126 Hz. For partly saturated...

  4. Bone-like crack resistance in hierarchical metastable nanolaminate steels

    Science.gov (United States)

    Koyama, Motomichi; Zhang, Zhao; Wang, Meimei; Ponge, Dirk; Raabe, Dierk; Tsuzaki, Kaneaki; Noguchi, Hiroshi; Tasan, Cemal Cem

    2017-03-01

    Fatigue failures create enormous risks for all engineered structures, as well as for human lives, motivating large safety factors in design and, thus, inefficient use of resources. Inspired by the excellent fracture toughness of bone, we explored the fatigue resistance in metastability-assisted multiphase steels. We show here that when steel microstructures are hierarchical and laminated, similar to the substructure of bone, superior crack resistance can be realized. Our results reveal that tuning the interface structure, distribution, and phase stability to simultaneously activate multiple micromechanisms that resist crack propagation is key for the observed leap in mechanical response. The exceptional properties enabled by this strategy provide guidance for all fatigue-resistant alloy design efforts.

  5. Surface cracking in resistance seam welding of coated steels

    Energy Technology Data Exchange (ETDEWEB)

    Adonyi, Y.; Kimchi, M.

    1994-12-31

    In this experimental work, the focus was on the understanding the electrode-wheel/coated steel surface phenomena by building operational lobes and by correlating the weld quality with static-and dynamic-contact-resistance variation during welding. Conventional AC, DC, and electrode-wire resistance-seam weldability of printed zinc-coated and hot-dipped tin-coated steel was performed in this work, as compared with traditional lead-tin (terne) coating used as reference material. Variables included steel substrate type, welding equipment type, electrode-wheel cleaning practice, and electrode-wire geometry. Optic and electron microscopy were used for the evaluation of specimens extracted from longitudinal cross-sections of representative welds. The size and morphology of surface cracks was characterized and correlated with variations in the above-mentioned parameters. It was found that the tin-coated (unpainted) steel sheet had a superior all-together performance to the zinc-coated steel and terne-coated steel, both in terms of wider weldability lobes and lesser surface cracking. The extent of surface cracking was greatly reduced by using the electrode-wire seam welding process using a longitudinally grooved wire profile, which also widened the corresponding weldability lobes. It was also found that the extent of cracking depended on the electrode knurl geometry, substrate type, and the presence of conductive paint applied on top of the metallic coating. An attempt was made to characterize the specific mechanisms governing the LME phenomenon for the lead-, zinc and tin-based coating systems and to assess the potential for crack propagation in the welds. The dynamic contact resistance was found to be a good measure of the welding process stability and an indicator of defect formation. It was found that the ratio between the static and dynamic contact resistances of the tin-coated sheet was considerably lower than similar ratios for bare and zinc-coated sheet.

  6. Resistance microwelding of 316L stainless steel wire to block

    DEFF Research Database (Denmark)

    Friis, Kasper Storgaard; Khan, M.I.; Bay, Niels

    2011-01-01

    The excellent corrosion resistance of low carbon vacuum melted 316 stainless steel coupled with its non-magnetic properties makes it ideal for biomedical applications. The typical joint geometry for microcomponents, such as medical implants, includes joining of fine wire to a larger block. However...

  7. Is cell viability always directly related to corrosion resistance of stainless steels?

    Energy Technology Data Exchange (ETDEWEB)

    Salahinejad, E., E-mail: salahinejad@kntu.ac.ir [Faculty of Materials Science and Engineering, K.N. Toosi University of Technology, Tehran (Iran, Islamic Republic of); Ghaffari, M. [Bruker AXS Inc., 5465 East Cheryl Parkway, Madison, WI 53711 (United States); Vashaee, D. [Electrical and Computer Engineering Department, North Carolina State University, Raleigh, NC 27606 (United States); Tayebi, L. [Department of Developmental Sciences, Marquette University School of Dentistry, Milwaukee, WI 53201 (United States); Department of Engineering Science, University of Oxford, Oxford OX1 3PJ (United Kingdom)

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn–Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn–Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. - Highlights: • Cell viability vs. corrosion resistance for medical-grade stainless steels • The stainless steel samples were prepared by powder metallurgy. • Unpenetrated additive played a critical role in the correlation.

  8. Studying microstructure of heat resistant steel deoxidized by barium ferrosilicon

    Directory of Open Access Journals (Sweden)

    A. Z. Issagulov

    2016-07-01

    Full Text Available The paper examined the nature and distribution of non-metallic inclusions in the heat-resistant steel 12H1MF (0,12 % С, 1 % Сr, 0,5 - 0,6 Mo, 0,5 % V, ferrosilicobarim. As a reference, used by steel, deoxidized silicon. Melting was carried out in a laboratory, research-metallic inclusions, their shape and distribution, pollution index were studied according to conventional methods. Studies have shown that ferrosilicobarim deoxidation in an amount of 0,1 - 0,2 %, reduce the overall pollution index of non-metallic inclusions and change the nature of their distribution.

  9. Oxidation resistant high creep strength austenitic stainless steel

    Science.gov (United States)

    Brady, Michael P.; Pint, Bruce A.; Liu, Chain-Tsuan; Maziasz, Philip J.; Yamamoto, Yukinori; Lu, Zhao P.

    2010-06-29

    An austenitic stainless steel displaying high temperature oxidation and creep resistance has a composition that includes in weight percent 15 to 21 Ni, 10 to 15 Cr, 2 to 3.5 Al, 0.1 to 1 Nb, and 0.05 to 0.15 C, and that is free of or has very low levels of N, Ti and V. The alloy forms an external continuous alumina protective scale to provide a high oxidation resistance at temperatures of 700 to 800.degree. C. and forms NbC nanocarbides and a stable essentially single phase fcc austenitic matrix microstructure to give high strength and high creep resistance at these temperatures.

  10. The influence of aluminum and carbon on the abrasion resistance of high manganese steels

    Science.gov (United States)

    Buckholz, Samuel August

    Abrasive wear testing of lightweight, austenitic Fe-Mn-Al-C cast steel has been performed in accordance with ASTM G65 using a dry sand, rubber wheel, abrasion testing apparatus. Testing was conducted on a series of Fe-30Mn-XAl-YC-1Si-0.5Mo chemistries containing aluminum levels from 2.9 to 9.5 wt.% and carbon levels from 0.9 to 1.83 wt.%. Solution treated materials having an austenitic microstructure produced the highest wear resistance. Wear resistance decreased with higher aluminum, lower carbon, and higher hardness after age hardening. In the solution treated condition the wear rate was a strong function of the aluminum to carbon ratio and the wear rate increased with a parabolic dependence on the Al/C ratio, which ranged from 1.8 to 10.2. Examination of the surface wear scar revealed a mechanism of plowing during abrasion testing and this method of material removal is sensitive to work hardening rate. Work hardening behavior was determined from tensile tests and also decreased with increasing Al/C ratio and after aging hardening. The loss of wear resistance is related to short range ordering of Al and C in the solution treated materials and kappa-carbide precipitation in age hardened materials and both contribute to planar slip and lower work hardening rates. A high carbon tool steel (W1) and a bainitic low alloy steel (SAE 8620) were also tested for comparison. A lightweight steel containing 6.5 wt.% Al and 1.2 wt.% C has wear resistance comparable to within 5% of the bainitic SAE 8620 steel forging currently used for the Bradley Fighting Vehicle track shoe and this cast Fe-Mn-Al-C steel, at equivalent tensile properties, would be 10% lighter.

  11. Tropical Weather Resistant Galvanized Steel Coated and Uncoated

    Directory of Open Access Journals (Sweden)

    Suárez-Corrales Xenia Isbel

    2014-01-01

    Full Text Available The corrosion behavior of coated and uncoated galvanized steel products is determined by exposing them to accelerated and natural climatic test. Accelerated tests were carried out in climatic chambers and natural atmospheric test in a marine-coastal station (Cojimar. The influence of tropical humid climate on these products is determined. Adhesion is an important property for a good performance, from the decorative point of view or as an additional protection. The evaluation indicates that 95% of the galvanized steel products show a good corrosion resistance; although 71% of coated galvanized products and 100% of painted galvanized products do not cover the requirements with respect to the mechanical and corrosion protection aspects. For a good efficiency and economic performance of metal mechanical industry, a correct surface treatment and coating application is required. A key point is to increase the quality by improving a better corrosion protective performance respecting uncoated galvanized steel.

  12. Development of Creep-Resistant and Oxidation-Resistant Austenitic Stainless Steels for High Temperature Applications

    Science.gov (United States)

    Maziasz, Philip J.

    2017-11-01

    Austenitic stainless steels are cost-effective materials for high-temperature applications if they have the oxidation and creep resistance to withstand prolonged exposure at such conditions. Since 1990, Oak Ridge National Laboratory (ORNL) has developed advanced austenitic stainless steels with creep resistance comparable to Ni-based superalloy 617 at 800-900°C based on specially designed "engineered microstructures" utilizing a microstructure/composition database derived from about 20 years of radiation effect data on steels. The wrought high temperature-ultrafine precipitate strengthened (HT-UPS) steels with outstanding creep resistance at 700-800°C were developed for supercritical boiler and superheater tubing for fossil power plants in the early 1990s, the cast CF8C-Plus steels were developed in 1999-2001 for land-based gas turbine casing and diesel engine exhaust manifold and turbocharger applications at 700-900°C, and, in 2015-2017, new Al-modified cast stainless steels with oxidation and creep resistance capabilities up to 950-1000°C were developed for automotive exhaust manifold and turbocharger applications. This article reviews and summarizes their development and their properties and applications.

  13. Development of Creep-Resistant and Oxidation-Resistant Austenitic Stainless Steels for High Temperature Applications

    Science.gov (United States)

    Maziasz, Philip J.

    2018-01-01

    Austenitic stainless steels are cost-effective materials for high-temperature applications if they have the oxidation and creep resistance to withstand prolonged exposure at such conditions. Since 1990, Oak Ridge National Laboratory (ORNL) has developed advanced austenitic stainless steels with creep resistance comparable to Ni-based superalloy 617 at 800-900°C based on specially designed "engineered microstructures" utilizing a microstructure/composition database derived from about 20 years of radiation effect data on steels. The wrought high temperature-ultrafine precipitate strengthened (HT-UPS) steels with outstanding creep resistance at 700-800°C were developed for supercritical boiler and superheater tubing for fossil power plants in the early 1990s, the cast CF8C-Plus steels were developed in 1999-2001 for land-based gas turbine casing and diesel engine exhaust manifold and turbocharger applications at 700-900°C, and, in 2015-2017, new Al-modified cast stainless steels with oxidation and creep resistance capabilities up to 950-1000°C were developed for automotive exhaust manifold and turbocharger applications. This article reviews and summarizes their development and their properties and applications.

  14. Color change and fracture resistance of two preveneered stainless-steel crowns after sterilization.

    Science.gov (United States)

    Wickersham, G T; Seale, N S; Frysh, H

    1998-01-01

    This study compared the fracture resistance and color stability of two commercially available, preveneered stainless-steel crowns before and after four sterilization techniques. Thirty-five crowns from each of two manufacturers were divided into five groups. Four groups were sterilized twice using one of the following techniques: steam autoclave at both 121 degrees C (15 PSI) for 20 min and 132 degrees C (30 PSI) for 8 min; Chemiclave with formaldehyde at 132 degrees C for 20 min; and 2% gluteraldehyde for 10 h. The fifth group from each manufacturer was the control. Color of facings was measured before and after each sterilization in triplicate using a colorimeter, and the variance of each color parameter was analyzed for significance. Fracture resistance was measured for each group and differences between the control and experimental groups analyzed for significance. The results of this study show that high heat and chemical sterilizations have little effect on color and fracture resistance of the preveneered stainless-steel crowns. Student's t test analysis revealed a significantly decreased resistance to fracture with Kinder Krowns sterilized in 2% gluteraldehyde. Chemiclave sterilization caused the most negative color change in all three color parameters measured for both types of crowns. As neither steam technique produced significant changes in fracture resistance or color changes that were clinically detectable, the results of this study indicate that the two steam techniques tested can be used by clinicians to sterilize either Kinder Krowns or Nu Smile preveneered stainless-steel crowns.

  15. Resistance of steel beams with web openings and castellated beams

    OpenAIRE

    Kovačič, Darko

    2010-01-01

    In Diploma demonstration of bending and shear resistance of steel beams with openings in web and for castellated beams is being presented. Dimensioning of such beams is performed in compliance with general rules by Eurocode for dimensioning of beams by considering speciality of beams with openings or by non-linear analysis with consideration of imperfections. For delimit of beams with openings from castellated beams, geometric criteria are being used. Further approach to the dimensioning of t...

  16. Formation of Surface Corrosion-Resistant Nanocrystalline Structures on Steel

    Science.gov (United States)

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha; Slobodyan, Zvenomyra; Tsyrulnyk, Oleksandr

    2016-02-01

    Engineering materials with nanocrystalline structure could be exploited under simultaneous action of mechanical loading and corrosion environments; therefore, their corrosion resistance is important. Surface nanocrystalline structure was generated on middle carbon steels by severe plastic deformation using the method of mechanical pulse friction treatment. This treatment additionally includes high temperature phase transformation and alloying. Using a complex of the corrosive, electrochemical and physical investigations, it was established that nanocrystalline structures can be characterized by lower or increased corrosion resistance in comparison with the reference material. It is caused by the action of two confronting factors: arising energy level and anticorrosive alloying of the surface layer.

  17. Aluminum nanocomposites having wear resistance better than stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    An, Linan [University of Central Florida; Qu, Jun [ORNL; Luo, Jinsong [Chinese Academy of Sciences; Fan, Yi [Chinese Academy of Sciences; Zhang, Ligong [University of Central Florida; Liu, Jinling [University of Central Florida; Xu, Chengying [University of Central Florida; Blau, Peter Julian [ORNL

    2011-01-01

    Tribological behavior of alumina-particle-reinforced aluminum composites made by powder metallurgy process has been investigated. The nanocomposite containing 15 vol% of Al2O3 nanoparticles exhibits excellent wear resistance by showing significantly low wear rate and abrasive wear mode. The wear rate of the nanocomposite is even lower than stainless steel. We have also demonstrated that such excellent wear resistance only occurred in the composite reinforced with the high volume fraction of nanosized reinforcing particles. The results were discussed in terms of the microstructure of the nanocomposite.

  18. Corrosion Resistance of Some Stainless Steels in Chloride Solutions

    Directory of Open Access Journals (Sweden)

    Kasprzyk D.

    2017-06-01

    Full Text Available The present work compares corrosion behaviour of four types of S30403, S31603, S32615 austenitic and S32404 austenitic-ferritic stainless steels in chloride solutions (1%, 3% NaCl and in Ringer solution, at 37°C temperature. Corrosion resistance was determined by potentiodynamic polarization measurements and a thirty day immersion test conducted in Ringer solution. The immersion test was performed in term of biomedical application. These alloy were spontaneously passivated in all electrolytes, wherein S30403, S31603 and S32404 undergo pitting corrosion. Only S32615 containing 5.5% Si shows resistance to pitting corrosion.

  19. Cracking resistance study of steel for gas pipelines; Badania odpornosci stali przeznaczonej na rurociagi gazowe

    Energy Technology Data Exchange (ETDEWEB)

    Wasiak, J.; Bilous, W.; Hajewska, E.; Szteke, W.; Wagner, T. [Institute of Atomic Energy, Otwock-Swierk (Poland)

    1996-12-31

    The results of cracking resistance of steel tubes for gas pipelines have been performed. The temperature dependence of mechanical properties of X56 steel used as tube material have been shown. 2 refs, 6 figs, 4 tabs.

  20. Effect of Isothermal Bainitic Quenching on Rail Steel Impact Strength and Wear Resistance

    Science.gov (United States)

    Çakir, Fatih Hayati; Çelik, Osman Nuri

    2017-09-01

    The effect of heat treatment regimes on hardness, impact strength, and wear resistance of rail steel for high-speed tracks (rail quality category R350HT) is studied. Analysis of steel properties with a different structure is compared: pearlitic, and upper and lower bainite. It is shown that the steel with bainitic structure has the best impact strength, but wear resistance is better for steel with a lower bainite structure.

  1. Is cell viability always directly related to corrosion resistance of stainless steels?

    Science.gov (United States)

    Salahinejad, E; Ghaffari, M; Vashaee, D; Tayebi, L

    2016-05-01

    It has been frequently reported that cell viability on stainless steels is improved by increasing their corrosion resistance. The question that arises is whether human cell viability is always directly related to corrosion resistance in these biostable alloys. In this work, the microstructure and in vitro corrosion behavior of a new class of medical-grade stainless steels were correlated with adult human mesenchymal stem cell viability. The samples were produced by a powder metallurgy route, consisting of mechanical alloying and liquid-phase sintering with a sintering aid of a eutectic Mn-Si alloy at 1050 °C for 30 and 60 min, leading to nanostructures. In accordance with transmission electron microscopic studies, the additive particles for the sintering time of 30 min were not completely melted. Electrochemical impedance spectroscopic experiments suggested the higher corrosion resistance for the sample sintered for 60 min; however, a better cell viability on the surface of the less corrosion-resistant sample was unexpectedly found. This behavior is explained by considering the higher ion release rate of the Mn-Si additive material, as preferred sites to corrosion attack based on scanning electron microscopic observations, which is advantageous to the cells in vitro. In conclusion, cell viability is not always directly related to corrosion resistance in stainless steels. Typically, the introduction of biodegradable and biocompatible phases to biostable alloys, which are conventionally anticipated to be corrosion-resistant, can be advantageous to human cell responses similar to biodegradable metals. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Corrosion Resistance of The Bearing Steel 67SiMnCr6-6-4 with Nanobainitic Structure

    Directory of Open Access Journals (Sweden)

    Skołek E.

    2015-04-01

    Full Text Available The paper describes a comparative study of the corrosion resistance of bearing steel 67SiMnCr6-6-4 after two kinds of nanostructuring treatments and two kinds of conventional quenching and tempering treatments. The nanostructuring treatment consisted of austempering with an isothermal quenching at 240°C and 300°C. The conventional heat treatment consisted on quenching and tempering at 350°C for 1 h and quenching and tempering at 550°C for 1 h. Time and temperature of tempering was chosen so that the hardness of both samples (nanostructured as well as quenched and tempered was similar. The microstructure of steel after each heat treatment was described with the use of transmission electron microscopy (TEM. It was shown, that the austempering conducted at 240°C produced homogenous nanobainitic structure consisting of carbide-free bainite plates with nanometric thickness separated by the layers of retained austenite. The austempering at 300°C produced a sub-micrometric carbide-free bainite with retained austenite in form of layers and small blocks. The conventional heat treatments led to a tempered martensite microstructure. The corrosion resistance study was carried out in Na2SO4 acidic and neutral environment using potentiodynamic and electrochemical impedance spectroscopy (EIS methods. The corrosion resistance of nanostructured steel samples were compared to the steel samples with tempered martensite. The obtained results indicate, that the corrosion resistance of bearing steel with nanobainitic structure is similar to steel with tempered martensite in both acidic and neutral environment. This means that the high density of intercrystalline boundaries in nanobinite does not deteriorate the corrosion properties of the bearing steel.

  3. Corrosion resistance of kolsterised austenitic 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Abudaia, F. B., E-mail: fabudaia@yahoo.com; Khalil, E. O., E-mail: ekhalil9@yahoo.com; Esehiri, A. F., E-mail: Hope-eseheri@hotmail.co.uk; Daw, K. E., E-mail: Khawladaw@yahoo.com [University of Tripoli Department of Materials and Metallurgical Eng, Tripoli-Libya P.O.Box13589 (Libya)

    2015-03-30

    Austenitic stainless suffers from low wear resistance in applications where rubbing against other surfaces is encountered. This drawback can be overcome by surface treatment such as coating by hard materials. Other treatments such as carburization at relatively low temperature become applicable recently to improve hardness and wear resistance. Carburization heat treatment would only be justified if the corrosion resistance is unaffected. In this work samples of 304 stainless steels treated by colossal supersaturation case carburizing (known as Kolsterising) carried out by Bodycote Company was examined for pitting corrosion resistance at room temperature and at 50 °C. Comparison with results obtained for untreated samples in similar testing conditions show that there is no deterioration in the pitting resistance due to the Kolsterising heat treatment. X ray diffraction patterns obtained for Kolsterising sample showed that peaks correspond to the austenite phase has shifted to lower 2θ values compared with those of the untreated sample. The shift is an indication for expansion of austenite unit cells caused by saturation with diffusing carbon atoms. The XRD of Kolsterising samples also revealed additional peaks appeared in the patterns due to formation of carbides in the kolsterised layer. Examination of these additional peaks showed that these peaks are attributed to a type of carbide known as Hagg carbide Fe{sub 2}C{sub 5}. The absence of carbides that contain chromium means that no Cr depletion occurred in the layer and the corrosion properties are maintained. Surface hardness measurements showed large increase after Kolsterising heat treatment.

  4. 9% Cr steel high temperature oxidation. Solutions investigated for improving corrosion resistance of the steel

    Energy Technology Data Exchange (ETDEWEB)

    Evin, Harold Nicolas; Heintz, Olivier; Chevalier, Sebastien [UMR 5209 CNRS-Bourgogne Univ. (France). Lab. Interdisciplinaire Carnot de Bourgogne; Foejer, Cecilia; Jakani, Saad; Dhont, Annick; Claessens, Serge [OCAS N.V. ArcelorMittal Global R and D, Gent (Belgium)

    2010-07-01

    The improvement of high temperature oxidation resistance of low chromium content steels, such as T/P91, is of great interest in regards with their application in thermal power generating plants. Indeed, they possess good creep properties, but are facing their limits of use at temperature higher than 600 C, due to accelerated corrosion phenomena. Good knowledge of the mechanisms involved during their oxidation process is needed to prevent the degradation of the materials and to extend life time of the power plants components. Oxide layers thermally grown, on 9% Cr steels (provided by OCAS N.V), during isothermal tests between 600 C and 750 C in laboratory air under atmospheric pressure were investigated, by Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD). The oxidation behaviour appeared very limited at 750 C, due to the presence of a breakaway, which can be linked to iron porous oxide grown over the surface of the samples. ''In situ'' X-ray Photoelectron spectroscopy (XPS) analyses were performed in air at 600 C after short exposures (between 5 min and 25 h). A complex mixture of iron oxide, Cr{sub 2}O{sub 3} and Cr (VI) species were characterized in the scales. The in-situ analyses were compared and related to XPS analyses performed on thick oxide scales formed on samples oxidized in air at 600 C for 100h. An oxidation mechanism is then proposed to understand the oxide scale growth in the temperature range 600 - 750 C. The second step of this study consists in improving the high temperature corrosion resistance of these steels without modifying their mechanical properties. Thus several solutions were investigated such as MOCVD coatings, pack cementation coatings, and tested in cycle conditions prior. (orig.)

  5. The Use of Nitriding to Enhance Wear Resistance of Cast Irons and 4140 Steel

    Science.gov (United States)

    Yang, Zaidao

    This research is focused on using nitriding to enhance the wear resistance of austempered ductile iron (ADI), ductile iron (DI), and gray iron (GI), and 4140 steel. Three gas nitriding processes, namely "Gas nitriding + nitrogen cooled down to 800°F (Blue)", "Gas nitriding + cooled down to 300°F (Gray)", and "Gas nitriding + oil quenched (Oil)" were used for the cast irons. Three salt bath nitriding processes, namely Isonite, QP (Quench, Polish) and QPQ (Quench, Polish, Quench) were used for the 4140 steel. This study was carried out through optical metallography, roughness measurements, microhardness, and SEM. The ball-on-disc wear tests were conducted under lubricated conditions. It was found that COF for all materials in all nitrided conditions was small (Gray and Oil gas nitriding processes. For the 4140 steel, The surface microhardness of the ISONITE specimen was around 1400HV. QP and QPQ processes produce a surface microhardness of 2000-2200HV, which suggests that they may show improved wear behaviour compared to ISONITE- treated steels.

  6. Comparison of Hydrogen Embrittlement Resistance between 2205 Duplex Stainless Steels and type 316L Austenitic Stainless Steels Under the Cathodic Applied Potential

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Dong-Il; Lee, Jae-Bong [Kookmin University, Seoul (Korea, Republic of)

    2016-10-15

    2205 duplex stainless steels have been used for the construction of the marine environment, because of their excellent corrosion resistance and high strength. However, the resistance to hydrogen embrittlement (HE) may be less than that of 316L austenitic stainless steel. The reason why 316L stainless steels have better resistance to HE is associated with crystal structure (FCC, face centered cubic) and the higher stacking faults energy than 2205 duplex stainless steels. Furthermore 2205 stainless steels with or without tungsten were also examined in terms of HE. 2205 stainless steels containing tungsten is less resistible to HE. It is because dislocation tangle was formed in 2205 duplex stainless steels. Slow strain-rate tensile test (SSRT) was conducted to measure the resistance to HE under the cathodic applied potential. Hydrogen embrittlement index (HEI) was used to evaluate HE resistance through the quantitative calculation.

  7. Surface modification to improve fireside corrosion resistance of Fe-Cr ferritic steels

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jong-Hee (Clarendon Hills, IL); Natesan, Krishnamurti (Naperville, IL); Rink, David L. (Mokena, IL)

    2010-03-16

    An article of manufacture and a method for providing an Fe--Cr ferritic steel article of manufacture having a surface layer modification for corrosion resistance. Fe--Cr ferritic steels can be modified to enhance their corrosion resistance to liquid coal ash and other chemical environments, which have chlorides or sulfates containing active species. The steel is modified to form an aluminide/silicide passivating layer to reduce such corrosion.

  8. Quality and properties of the cast iron produced on the steel scrap base

    OpenAIRE

    K. Janerka; J. Jezierski; J. Szajnar

    2012-01-01

    Purpose: The goal of the article is to show the issue of the cast iron melting on the steel scrap base only (with no pig iron in charge). The particular interest was focused on the charging material chemical composition influence on the particular elements content in produced cast iron and its quality, too.Design/methodology/approach: The grey cast iron melting on the steel scrap base and recarburizers (anthracite, natural and synthetic graphite, petroleum coke) was conducted to achieve the g...

  9. W–steel and W–WC–steel composites and FGMs produced by hot pressing

    Czech Academy of Sciences Publication Activity Database

    Matějíček, Jiří; Boldyryeva, Hanna; Brožek, Vlastimil; Sachr, P.; Chráska, Tomáš; Pala, Zdeněk

    2015-01-01

    Roč. 100, November (2015), s. 364-370 ISSN 0920-3796 R&D Projects: GA ČR(CZ) GAP108/12/1872 EU Projects: European Commission(DE) WP11-MAT-WWALLOY Institutional support: RVO:61389021 Keywords : FGM * Composite * Tungsten * Steel * Fusion reactor material Subject RIV: JI - Composite Materials Impact factor: 1.301, year: 2015 http://www.sciencedirect.com/science/article/pii/S0920379615302106

  10. Producing Durable Continuously Reinforced Concrete Pavement using Glass-ceramic Coated Reinforcing Steel

    Science.gov (United States)

    2010-02-01

    surrounding concrete Steel Reinforcement BUILDING STRONG® Properties of Coating  Covers the reinforcement with an insulator  Does not delaminate...The enameled rebar can be manufactured using the conventional enamel application methods and modification of standard alkali-resistant porcelain

  11. The effect of alloying on the resistance of carbon steel for oilfield applications to CO2 corrosion

    Directory of Open Access Journals (Sweden)

    David V. Edmonds

    2005-12-01

    Full Text Available A systematic study has been conducted to investigate the influence of a wide range of alloying elements and different processing conditions on the resistance of low-carbon steels to CO2 corrosion. Strong carbide-forming microalloying elements such as Ti, Nb and V, along with Cr additions, and different levels of Mn, Si, Cu, Mo and Ni, have been explored, along with treatments simulating different processing conditions, for example, controlled rolling, and quenching and tempering. Corrosion testing, including flow loop tests, has been carried out, along with evaluation of mechanical properties, weldability and hot ductility. The programme has developed steels with improved CO2 corrosion resistance and hence identified a potential route for producing more economical carbon steels for oilfield applications. The work has been carried out as part of the UK- Brazil Corrosion Network.

  12. Fatigue behavior of functionally graded steel produced by electro-slag remelting

    Energy Technology Data Exchange (ETDEWEB)

    Salehi, M., E-mail: m-salehi@aut.ac.ir [Department of Mechanical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Alizadeh Vaghasloo, Y., E-mail: alizadeh@aut.ac.ir [Department of Mechanical Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Naderi, M., E-mail: mnaderi@aut.ac.ir [Department of Mining and Metallurgical Engineering Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ramezani Movaffagh, M., E-mail: m68rm@aut.ac.ir [Department of Mining and Metallurgical Engineering Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Varmaziar, A., E-mail: varmaziar@aut.ac.ir [Department of Mining and Metallurgical Engineering Engineering, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)

    2013-11-01

    The present study attempts to investigate the fatigue behavior of functionally graded steel (FGS) produced through electroslag remelting (ESR) process. To produce FGSs, two different slices of plain carbon steel and austenitic stainless steel were welded and used as ESR's electrode. Some of alloying elements in austenitic stainless steel, such as Nickel and Chromium, as well as carbon in plain carbon steel may be replaced during remelting stage; graded layers (austenite and martensite layers) may also be fabricated. Vickers micro-hardness test and scanning electron microscopy (SEM) of FGS were performed and variations in hardness and microstructure were observed. SEM images exhibited multi-phase graded steel. The rotating bending fatigue test was performed on specimens. The fatigue test results showed improvement in fatigue limit of FGS in comparison with that of its ingredients. SEM's images of fatigue fracture surfaces in FGS showed deviation and branching in crack propagation when crack propagates from graded austenite to graded martensite phase.

  13. 76 FR 55004 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary...

    Science.gov (United States)

    2011-09-06

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... of the antidumping order on corrosion-resistant carbon steel flat products (CORE) from the Republic... Antidumping Duty Orders on Certain Cold-Rolled Carbon Steel Flat Products and Certain Corrosion-Resistant...

  14. 77 FR 31877 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five...

    Science.gov (United States)

    2012-05-30

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Scheduling of Full Five... duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to lead to...

  15. 77 FR 14501 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2012-03-12

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... antidumping duty administrative review for certain corrosion-resistant carbon steel flat products (CORE) from... (POR) is August 1, 2009, through, July 31, 2010. \\1\\ See Certain Corrosion-Resistant Carbon Steel Flat...

  16. 76 FR 15291 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2011-03-21

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea). See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

  17. 77 FR 44213 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea...

    Science.gov (United States)

    2012-07-27

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... certain corrosion-resistant carbon steel flat products (``CORE'') from Germany and the Republic of Korea..., Director, Office 3, on ``Sunset Reviews of the Antidumping Duty Orders on Corrosion-Resistant Carbon Steel...

  18. 75 FR 55769 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2010-09-14

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... administrative review of the antidumping order on corrosion-resistant carbon steel flat products (CORE) from the... Antidumping Duty Orders on Certain Cold-Rolled Carbon Steel Flat Products and Certain Corrosion-Resistant...

  19. 77 FR 72827 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea: Final...

    Science.gov (United States)

    2012-12-06

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... on certain corrosion- resistant carbon steel flat products (``CORE'') from Germany and the Republic... Reviews'' section of this notice. \\1\\ Corrosion-Resistant Carbon Steel Flat Products From Germany and the...

  20. 78 FR 59651 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2013-09-27

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... fourteenth administrative review of the antidumping duty order on certain corrosion-resistant carbon steel... aspects of the Final Results. \\2\\ See Certain Corrosion-Resistant Carbon Steel Flat Products from the...

  1. 78 FR 16247 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea; Final Results of...

    Science.gov (United States)

    2013-03-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea... section entitled ``Final Results of Review.'' \\1\\ See Certain Corrosion-Resistant Carbon Steel Flat...

  2. 77 FR 301 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea: Institution of Five-Year...

    Science.gov (United States)

    2012-01-04

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea: Institution of Five-Year Reviews Concerning the Countervailing Duty Order on Corrosion-Resistant Carbon Steel Flat Products From Korea and the Antidumping Duty Orders on Corrosion-Resistant Carbon Steel Flat Products From Germany and...

  3. 75 FR 55745 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results...

    Science.gov (United States)

    2010-09-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea) for the period of... preliminary results of the instant administrative review. See Corrosion-Resistant Carbon Steel Flat Products...

  4. 77 FR 24221 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission...

    Science.gov (United States)

    2012-04-23

    ... COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Notice of Commission... countervailing duty order on corrosion-resistant carbon steel flat products from Korea and the antidumping duty orders on corrosion- resistant carbon steel flat products from Germany and Korea would be likely to lead...

  5. 78 FR 16832 - Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic of Korea: Revocation...

    Science.gov (United States)

    2013-03-19

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and the Republic... corrosion-resistant carbon steel flat products (``CORE'') from Germany and the Republic of Korea (``Korea...-Year (``Sunset'') Review, 77 FR 85 (January 3, 2012). \\2\\ See Corrosion-Resistant Carbon Steel Flat...

  6. 77 FR 54891 - Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary...

    Science.gov (United States)

    2012-09-06

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of... administrative review of the antidumping order on corrosion-resistant carbon steel flat products (CORE) from the... the order on March 12, 2012. See Certain Corrosion- Resistant Carbon Steel Flat Products From the...

  7. 78 FR 55057 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2013-09-09

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea... antidumping duty order on corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea.... See Corrosion-Resistant Carbon Steel Flat Products from Germany and the Republic of Korea: Revocation...

  8. 77 FR 13093 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2012-03-05

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... administrative review of the countervailing duty (``CVD'') order on corrosion-resistant carbon steel flat... Review'' below. \\1\\ See Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea...

  9. 76 FR 77775 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2011-12-14

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea... countervailing duty order on corrosion-resistant carbon steel flat products from the Republic of Korea covering the period January 1, 2009, through December 31, 2009. See Corrosion-Resistant Carbon Steel Flat...

  10. 78 FR 59652 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2013-09-27

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of... administrative review of the antidumping duty order on certain corrosion-resistant carbon steel flat products... Results. \\2\\ See Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Notice...

  11. 75 FR 13490 - Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Notice of...

    Science.gov (United States)

    2010-03-22

    ... International Trade Administration (A-580-816) Certain Corrosion-Resistant Carbon Steel Flat Products from the... administrative review for certain corrosion-resistant carbon steel flat products (CORE) from the Republic of Korea (Korea). See Certain Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea...

  12. 76 FR 3613 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2011-01-20

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... review of the countervailing duty (CVD) order on corrosion-resistant carbon steel flat products (CORE..., 2008. See Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Preliminary...

  13. Effect of hydrodynamics and surface roughness on the electrochemical behaviour of carbon steel in CSG produced water

    Energy Technology Data Exchange (ETDEWEB)

    Eyu, Gaius Debi; Will, Geoffrey, E-mail: g.will@qut.edu.au; Dekkers, Willem; MacLeod, Jennifer

    2015-12-01

    Highlights: • Surface roughness increases the anodic current density under dynamic conditions. • Pitting corrosion increases with an increasing surface roughness for carbon steel in coal seam gas produced water. • Flow accelerates the mass transfer of the corrosion product under dynamic conditions. • Corrosion rate of carbon steel decreased with immersion time. - Abstract: The influence of fluid flow, surface roughness and immersion time on the electrochemical behaviour of carbon steel in coal seam gas produced water under static and hydrodynamic conditions has been studied. The disc electrode surface morphology before and after the corrosion test was characterized using scanning electron microscopy (SEM). The corrosion product was examined using X-ray photoelectron spectroscopy (XPS) and X-ray diffractometry (XRD).The results show that the anodic current density increased with increasing surface roughness and consequently a decrease in corrosion surface resistance. Under dynamic flow conditions, the corrosion rate increased with increasing rotating speed due to the high mass transfer coefficient and formation of non-protective akaganeite β-FeO(OH) and goethite α-FeO(OH) corrosion scale at the electrode surface. The corrosion rate was lowest at 0 rpm. The corrosion rate decreased in both static and dynamic conditions with increasing immersion time. The decrease in corrosion rate is attributed to the deposition of corrosion products on the electrode surface. SEM results revealed that the rougher surface exhibited a great tendency toward pitting corrosion.

  14. The corrosion resistance of 140MXC, 530AS and 560AS coatings produced by thermal spraying

    Directory of Open Access Journals (Sweden)

    Edwin Alexis López Covaleda

    2013-04-01

    Full Text Available Three commercial materials were deposited using electric arc thermal spraying: 140MXC (with Fe, W, Cr, Nb, 530AS (AISI 1015 steel and 560AS (AISI 420 steel on AISI 4340 steel. The aim of this paper was to evaluate the best strategy for improving a coating-substrate system’s corrosion resistance, using the following combinations: homogeneous single coatings, bilayers consisting of 530AS or 560AS under 140MXC and 140MXC + 530AS and 140MXC + 560AS coatings deposited simultaneously. The coatings were characterised using optical microscopy, scanning electron microscopy and X-ray diffraction. Corrosion resistance was evaluated through potentiodynamic polarisation and hardness by using the Vickers test. Corrosion resistance depends on the amount of microstructure defects, the deposition strategy and the alloy elements. However, corrosion resistance was similar in single coatings of 140MXC and bilayers, having -630 V corrosion potential and 708 nA corrosion current. The details and corrosion mechanism of the coatings so produced are described in this paper.

  15. Produce logistics simulation in a section steel mill

    Science.gov (United States)

    Chen, Chenglang; Xie, Zhijiang; Liang, Tiantian

    2005-12-01

    A new universal rolling production line's produce logistics simulation system has been successfully designed and put into practice with the help of eM-plant. It can not only simulate the whole process, but also get statistics of the whole production line and each working procedure's capacity. Meanwhile, it can provide relevant decision-making support by simulating new product before putting into production. By running it, the line's bottleneck can be found out and an optimal produce logistics model can be designed. Comparing the improved one with the original, a better decision can be deduced. Application indicates that the simulation model can precisely simulate the production line's condition. And experimental and debugging time of new product can be reduced sharply.

  16. Multilayer Steel Materials Deformation Resistance and Roll Force Measurement

    Directory of Open Access Journals (Sweden)

    A. G. Kolesnikov

    2014-01-01

    Full Text Available To create new types of cars, raise their reliability, gain operational life, and decrease in metal consumption of products it is necessary to improve mechanical, physical, and also special properties of the constructional materials applied in mechanical engineering. Presently, there are intensive researches and developments under way to create materials with ultrafine-grained structure (the sizes of grains in their crystal lattice make less than 1 micron in one of the measurements.BMSTU developed a manufacturing technology of multilayer steel sheets with steady ultrafine-grained structure based on the multiple hot rolling of billet as a composition consisting of the alternating metal sheets. A principled condition for implementation of such technology is existence of different crystallographic modifications in the adjoining sheets of the composition at specified temperature of rolling.Power parameters of rolling are important technical characteristics of the process. Usually, to determine a deformation resistance value when rolling the diverse multilayer materials, is used the actual resistance value averaging in relation to the components of the composition. The aim of this work is a comparative analysis of known calculated dependences with experimental data when rolling the 100-layer samples. Objects of research were the 100-layer compositions based on the alternating layers of steel 08H18N10 and U8.Experimental samples represented the vacuumized capsules with height, width, and length of 53 mm x 53 mm x 200 mm, respectively, in which there were the 100-layer packs from sheets, each of 0.5 mm, based on the composition of steels (U8+08H18N10. Rolling was made on the double-high mill with rolls of 160 mm in diameter during 19 passes to the thickness of 7 mm with the speed of 0,1 m/s. Relative sinking in each pass was accepted to be equal 10±2,5%. Rolling forces were measured by the strain-gauging method using the measuring cells, located under

  17. Influence of surface roughness of stainless steel on microbial adhesion and corrosion resistance

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Bagge-Ravn, Dorthe; Kold, John

    2003-01-01

    was not affected by surface roughness (Ra) ranging from grit 4000 polished stainless steel (Ra resistance...... was evaluated in a commercial disinfectant and in 1 M NaCl. Electropolished and grit 4000 polished steel proved more corrosion resistant as opposed to grit 80 and 120 polished surfaces. In conclusion, the surface finish did not influence bacterial attachment, colonisation, or removal, but is an important...... parameter for the corrosion resistance of the surface....

  18. TOPICAL REVIEW: Corrosion resistance of Si–Al-bearing ultrafine-grained weathering steel

    Directory of Open Access Journals (Sweden)

    Toshiyasu Nishimura

    2008-01-01

    Full Text Available In the Ultra-steel project at the National Institute for Materials Science (NIMS, which run from 1996 to 2005, high-Si–Al-content ultrafine-grained (UFG weathering steel was developed by grain refinement and weathering guidance. It was found that this steel has excellent strength, toughness and corrosion resistance. Samples were prepared by multi pass warm rolling at temperatures between 773 and 873 K. The grain size of steel rolled at 873 K was about 1 μ m, and the tensile strength (TS and elongation (EL had excellent values of 800 MPa and 20%, respectively. In general, steels with high Si and Al contents exhibit inferior toughness to carbon steel (SM; however, the toughness of the developed sample was markedly improved by grain refinement. Cyclic corrosion tests in the presence of chloride ions confirmed that the developed steel exhibited excellent corrosion resistance, superior to that of SM. Electron probe microanalysis (EPMA and transmission electron microscopy (TEM analyses showed that Si and Al mainly exist in the inner rust layer. Si and Al were identified as existing in the Si2 + and Al3 + states in the nanoscale complex oxides constituting the inner rust layer. Electrochemical impedance spectroscopy(EIS measurement showed that the corrosion reaction resistance (Rt of the developed steel was much greater than that of SM. In the developed steel, the nanoscale complex oxides were formed in the inner rust layer, which increased Rt, and resulted in the excellent corrosion resistance.

  19. Influence of Nitrided Layer on The Properties of Carbon Coatings Produced on X105CrMo17 Steel Under DC Glow-Discharge Conditions

    Directory of Open Access Journals (Sweden)

    Tomasz BOROWSKI

    2016-09-01

    Full Text Available In most cases, machine components, which come in contact with each other, are made of steel. Common steel types include 100Cr6 and X105CrMo17 are widely used in rolling bearings, which are subjected to high static loads. However, more and more sophisticated structural applications require increasingly better performance from steel. The most popular methods for improving the properties of steel is carburisation or nitriding. Unfortunately, when very high surface properties of steel are required, this treatment may be insufficient. Improvement of tribological properties can be achieved by increasing the hardness of the surface, reducing roughness or reducing the coefficient of friction. The formation of composite layers on steel, consisting of a hard nitride diffusion layer and an external carbon coating with a low coefficient of friction, seems to be a prospect with significant potential. The article describes composite layers produced on X105CrMo17 steel and defines their morphology, surface roughness and their functional properties such as: resistance to friction-induced wear, coefficient of friction and corrosion resistance. The layers have been formed at a temperature of 370°C in successive processes of: nitriding in low-temperature plasma followed by deposition of a carbon coating under DC glow-discharge conditions. An evaluation was also made of the impact of the nitrided layers on the properties and morphology of the carbon coatings formed by comparing them to coatings formed on non-nitrided X105CrMo17 steel substrates. A study of the surface topography, adhesion, resistance to friction-induced wear and corrosion shows the significant importance of the substrate type the carbon coatings are formed on.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7532

  20. Corrosion Behavior of Carbon Steel in Synthetically Produced Oil Field Seawater

    Directory of Open Access Journals (Sweden)

    Subir Paul

    2014-01-01

    Full Text Available The life of offshore steel structure in the oil production units is decided by the huge corrosive degradation due to SO42-, S2−, and Cl−, which normally present in the oil field seawater. Variation in pH and temperature further adds to the rate of degradation on steel. Corrosion behavior of mild steel is investigated through polarization, EIS, XRD, and optical and SEM microscopy. The effect of all 3 species is huge material degradation with FeSx and FeCl3 and their complex as corrosion products. EIS data match the model of Randle circuit with Warburg resistance. Addition of more corrosion species decreases impedance and increases capacitance values of the Randle circuit at the interface. The attack is found to be at the grain boundary as well as grain body with very prominent sulphide corrosion crack.

  1. Predicting the Abrasion Resistance of Tool Steels by Means of Neurofuzzy Model

    Directory of Open Access Journals (Sweden)

    Dragutin Lisjak

    2013-07-01

    Full Text Available This work considers use neurofuzzy set theory for estimate abrasion wear resistance of steels based on chemical composition, heat treatment (austenitising temperature, quenchant and tempering temperature, hardness after hardening and different tempering temperature and volume loss of materials according to ASTM G 65-94. Testing of volume loss for the following group of materials as fuzzy data set was taken: carbon tool steels, cold work tool steels, hot work tools steels, high-speed steels. Modelled adaptive neuro fuzzy inference system (ANFIS is compared to statistical model of multivariable non-linear regression (MNLR. From the results it could be concluded that it is possible well estimate abrasion wear resistance for steel whose volume loss is unknown and thus eliminate unnecessary testing.

  2. Creep resistant, precipitation-dispersion-strengthened, martensitic stainless steel and method thereof

    Science.gov (United States)

    Buck, R.F.

    1994-05-10

    An iron-based, corrosion-resistant, precipitation strengthened, martensitic steel essentially free of delta ferrite for use at high temperatures has a nominal composition of 0.05--0.1 C, 8--12 Cr, 1--5 Co, 0.5--2.0 Ni, 0.41--1.0 Mo, 0.1--0.5 Ti, and the balance iron. This steel is different from other corrosion-resistant martensitic steels because its microstructure consists of a uniform dispersion of fine particles, which are very closely spaced, and which do not coarsen at high temperatures. Thus at high temperatures this steel combines the excellent creep strength of dispersion-strengthened steels, with the ease of fabricability afforded by precipitation hardenable steels. 2 figures.

  3. Influence of Heat Treatments on the Corrosion Resistance of Medium -Carbon Steel using Sulfuric Spring Water

    Directory of Open Access Journals (Sweden)

    Ikhlas Basheer

    2015-02-01

    Full Text Available The corrosion is one of the important problems that may be occur to the parts of machinery and equipment after manufactured and when used as a result of exposure to corrosive media. Plain-carbon steel is considered as one of the most common minerals used in industrial applications. Some of heat treatments can have direct effect on the corrosion rate of steel by building up galvanic corrosion cells between its microscopic phases. Therefore, to adopt one of kinds of the plain-carbon steel and the most commonly used in industry to be study subject, that is medium carbon steel and took samples of this steel has been treated thermally in three methods which the normalising, annealing, and hardening .The corrosive media used in the research is Sulfuric Spring, it contains many chemical compounds to show its influence on the corrosion of steel. The weight loss method is used to determine corrosion rate and to compare between the results obtained, show that the greatest corrosion resistance of the annealed steel and the corrosion resistance of the hardened steel is the lowest while the corrosion  resistance of the normalised steel is in-between them.         Calcium carbonate was formed on the metal surface which acts as an isolating layer which decrease corrosion rate with time

  4. Effect of Boronizing on Microhardness and Wear Resistance of Steel AISI 1050 and Chilled Cast Iron

    Science.gov (United States)

    Calik, Adnan; Simsek, Mithat; Karakas, Mustafa Serdar; Ucar, Nazim

    2014-05-01

    Steel AISI 1050 (steel 50) and chilled cast iron are studied after 5-h solid-phase boronizing from a powder environment at 900 °C. The surfaces of the boronized specimens are studied by x-ray and electron microscopic analyses and their Vickers microhardness is measured. The wear resistance is determined by the pin-on-disc method.

  5. Copper modified austenitic stainless steel alloys with improved high temperature creep resistance

    Science.gov (United States)

    Swindeman, R.W.; Maziasz, P.J.

    1987-04-28

    An improved austenitic stainless steel that incorporates copper into a base Fe-Ni-Cr alloy having minor alloying substituents of Mo, Mn, Si, T, Nb, V, C, N, P, B which exhibits significant improvement in high temperature creep resistance over previous steels. 3 figs.

  6. INFLUENCE OF ADDITIVES ON THE STRUCTURE FORMING OF ECONOMICALLY-ALLOYED WEAR RESISTING STEEL

    Directory of Open Access Journals (Sweden)

    A. I. Garost

    2007-01-01

    Full Text Available The characteristics of vanadium and nitrogencontaining economically-alloyed wear-resisting steels are investigated. The micro-composition and nature of nonmetallic impurities of steels with lowered content of manganese are studied. The optimal compositions of alloys for castings are offered.

  7. Cavitation erosion resistance of 13/4 and 21-4-N steels

    Indian Academy of Sciences (India)

    The cavitation erosion is highly dependent on microstructure and mechanical properties. The results show that hot rolled 21-4-N steel is more cavitation erosion resistant than the 13/4 and 21-4-N steels in as cast condition. The eroded surfaces were analysed through optical microscope and scanning electron microscope ...

  8. Influence of annealing heat treatment on pitting corrosion resistance of stainless steel type 316

    Directory of Open Access Journals (Sweden)

    Amirreza Bakhtiari

    2014-07-01

    Full Text Available The effect of annealing heat treatment on pitting resistance of stainless steel type 316L has been studied using Tafel polarization and ASTM G150 for estimating of the pitting potential and CPT, respectively. The materials were tested in 3.5% NaCl solution. The chemical composition of the material was analyzed via optical emission spectrometry. It was found that the sample treated at 940°C shows better pitting corrosion resistance than samples treated at 520°C and 820°C. The treatment at 940°C produced two types of morphologies, austenitic-ferritic matrix with δ-ferrite and only small amount of the σ phase. In the range up to 820°C the σ phase embedded in the γ phase matrix and at δ/γ interface was causing brittleness of the material and aggravated corrosion resistance. The treatment at 940°C produced the microstructure which prevented the corrosion attack to develop. It was revealed that the pitting size in samples treated at 520°C and 820°C is greater than that at 940°C. In addition, depth of pitting has been considered as a factor of pitting corrosion resistance. The depth of pitting in sample treated at 940°C is low since the pitting is almost superficial, while the pitting size in samples treated in 520°C and 820°C is higher and deeper.

  9. Comparison of Maraging Steel Micro- and Nanostructure Produced Conventionally and by Laser Additive Manufacturing

    OpenAIRE

    Jägle, Eric A.; Zhendong Sheng; Philipp Kürnsteiner; Sörn Ocylok; Andreas Weisheit; Dierk Raabe

    2017-01-01

    Maraging steels are used to produce tools by Additive Manufacturing (AM) methods such as Laser Metal Deposition (LMD) and Selective Laser Melting (SLM). Although it is well established that dense parts can be produced by AM, the influence of the AM process on the microstructure—in particular the content of retained and reversed austenite as well as the nanostructure, especially the precipitate density and chemistry, are not yet explored. Here, we study these features using microhardness measu...

  10. Corrosion resistance of different metallic coatings on press-hardened steels for automotive

    Energy Technology Data Exchange (ETDEWEB)

    Dosdat, L.; Petitjean, J.; Vietoris, T. (ArcelorMittal Maizieres Automotive Products Research Centre, F-57283 Maizieres-les-Metz); Clauzeau, O. [Bohr Technologies (France)

    2011-06-15

    The corrosion resistance of laboratory press-hardened components in aluminized, galvanized or galvannealed boron steels was evaluated through VDA 621-415 cyclic test for the automotive industry. 22MnB5 uncoated steel for hot stamping and standard galvanized steel for cold forming were also included as references. Corrosion resistance after painting (cosmetic corrosion) was quantified by measuring the delamination of electro-deposited paint from scribed panels. The rusting on their edges was used for determining the cut-edge corrosion resistance. The corrosion resistance on unpainted deformed panels (perforating corrosion) was quantified by mass losses and pit depth measurements. Zinc-coated boron steels were found to be more resistant to cosmetic corrosion than the other materials, and slightly more resistant to cut-edge corrosion than the aluminized one. Red rust apparition could not be avoided due to the high iron content in all these hot-stamped coatings. The three coated boron steels showed similar performances in terms of resistance to perforation. Aluminized boron steel presents the advantage of being less sensitive to hot-stamping process deviation. Its robustness has been proved for many years on cars. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Corrosion resistance of CrN thin films produced by dc magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Ruden, A. [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al Magdalena, Manizales (Colombia); Laboratorio de Recubrimientos Duros y Aplicaciones Industriales–RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia); Departamento de matemáticas, Universidad Tecnológica de Pereira, Pereira (Colombia); Restrepo-Parra, E., E-mail: erestrepopa@unal.edu.co [Laboratorio de Física del Plasma, Universidad Nacional de Colombia Sede Manizales, Km. 9 vía al Magdalena, Manizales (Colombia); Paladines, A.U.; Sequeda, F. [Laboratorio de Recubrimientos Duros y Aplicaciones Industriales–RDAI, Universidad del Valle, Calle 13 N° 100-00 Ciudadela Meléndez, Cali (Colombia)

    2013-04-01

    In this study, the electrochemical behavior of chromium nitride (CrN) coatings deposited on two steel substrates, AISI 304 and AISI 1440, was investigated. The CrN coatings were prepared using a reactive d.c. magnetron sputtering deposition technique at two different pressures (P1 = 0.4 Pa and P2 = 4 Pa) with a mixture of N{sub 2}–Ar (1.5-10). The microstructure and crystallinity of the CrN coatings were investigated using X-ray diffraction. The aqueous corrosion behavior of the coatings was evaluated using two methods. The polarization resistance (Tafel curves) and electrochemical impedance spectra (EIS) in a saline (3.5% NaCl solution) environment were measured in terms of the open-circuit potentials and polarization resistance (R{sub p}). The results indicated that the CrN coatings present better corrosion resistance and R{sub p} values than do the uncoated steel substrates, especially for the coatings produced on the AISI 304 substrates, which exhibited a strong enhancement in the corrosion resistance. Furthermore, better behavior was observed for the coatings produced at lower pressures (0.4 Pa) than those grown at 4 Pa.

  12. APPLICATION OF BARIUMSTRONTIUM CARBONATES FOR PROCESSING OF CREEP-RESISTING STEELS

    Directory of Open Access Journals (Sweden)

    A. P. Bezhok

    2011-01-01

    Full Text Available The results of researches on influence of bariumstrontium carbonates on structure, mechanical and foundry properties of heat resisting chrome-nickel steels of austenitic type are given.

  13. Corrosion resistance enhancement of SAE 1020 steel after Chromium implantation by nitrogen ion recoil

    National Research Council Canada - National Science Library

    Geraldo Francisco Gomes; Mario Ueda; Antonio Fernando Beloto; Roberto Zenhei Nakazato; Helfried Reuther

    2005-01-01

    SAE 1020 construction steel is widely used as mortar reinforcement and small machine parts, but aside good surface properties as high ductility, hardness and wear resistance, its surface is prone to severe corrosion...

  14. Microstructures and mechanical properties of 9Cr oxide dispersion strengthened steel produced by spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Rui [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); School of Metallurgy, Northeastern University, Shenyang 110819 (China); Lu, Zheng, E-mail: luz@atm.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Lu, Chenyang; Li, Zhengyuan [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China); Ding, Xueyong [School of Metallurgy, Northeastern University, Shenyang 110819 (China); Liu, Chunming [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Materials Science and Engineering, Northeastern University, Shenyang 110819 (China)

    2017-02-15

    Highlights: • A 9Cr-ODS steel was produced by mechanical alloying and spark plasma sintering. • Bimodal grain size distribution was observed. • Formation mechanism of bimodal grain size distribution was discussed. • The size and number density of nanoscale particles were obtained by SAXS and HRTEM. • The contribution of nano-sized particles to yield strength is dominating. - Abstract: 9Cr oxide dispersion strengthened (ODS) steel was fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The nano-sized particles, grain size distribution and mechanical properties of 9Cr-ODS steel sintered at 950 °C were studied by synchrotron radiation small angle X-ray scattering (SAXS), high-resolution transmission electron microscopy (HRTEM), electron backscatter diffraction (EBSD) and tensile experiment. The results showed that bimodal grain size distribution in the matrix is observed, which is attributed to the heterogeneous recrystallization process during the SPS. High-density nano-sized Y{sub 2}Ti{sub 2}O{sub 7} and some large oxides of Cr{sub 2}Mn(Ti)O{sub 4} are formed in 9Cr-ODS steel. The number density and average size of Y{sub 2}Ti{sub 2}O{sub 7} obtained from SAXS are 4.72 × 10{sup 22}/m{sup 3} and 4.4 nm, respectively. The yield strengths of 9Cr-ODS steel fabricated by SPS are compared with the typical 9Cr-ODS steel produced by HIP.

  15. Laboratory Investigation of Skid Resistance for Steel Slag Utilization as Chip Seal

    OpenAIRE

    Fitria Hidayatiningrum, Laely; Budi Suparma, Latif

    2011-01-01

    Slag as waste material of steel-making process has similar characteristics with aggregate that has been widely used in pavement construction. The use of slag as chip seal aggregate to provide skid resistance needs to be analyzed. In this laboratory study, the chip seal samples are made using steel slag and natural aggregate. The bonding materials used are asphalt and epoxy resin. Skid resistance tests for all chip seal samples and also hot rolled sheet pavement without chip seal application a...

  16. Effect of quenching method on the wear and corrosion resistance of stainless steel AISI 420 (TYPE 30Kh13)

    Science.gov (United States)

    Sola, R.; Giovanardi, R.; Veronesi, P.; Poli, G.

    2013-03-01

    The effect of different kinds of quenching, i.e., laser, vacuum, and induction ones, on the mechanical properties and wear and corrosion resistances of stainless steel AISI 420 is studied. It is shown that all the three kinds of heat treatment raise considerably the wear resistance of the steel due to growth in the hardness. Laser and vacuum quenching also increases the corrosion resistance. After induction quenching the resistance to corrosion is lower than in untreated steel.

  17. Microstructural Characterization for Structural Health Monitoring of Heat-Resisting Rotor Steels

    Energy Technology Data Exchange (ETDEWEB)

    Kim, C. S.; Byeon, J. W.; Park, I. K. [Seoul National University of Technology, Seoul (Korea, Republic of)

    2008-04-15

    The typical heat-resisting rotor steels such as 2.25CrMo, 9CrMo and 12CrW steel were experimentally studied in order to understand their materials degradation under high temperature and pressure during the long-term service, and then use the basic studies for the structural health monitoring. In order to monitor the materials degradation, it was conducted by the isothermal aging for 2.25CrMo steel, creep-fatigue for 9CrMo steel and creep for 12Cr steel with the incremental step test. The ultrasonic wave properties, electrical resistivity and coercivity were interpreted in relation to microstructural changes at each material and showed strong sensitivity to the specific microstructural evolution

  18. Investigation of Wear Resistant of Low-Alloyed and Chromium Cast Steel

    Directory of Open Access Journals (Sweden)

    A. Studnicki

    2012-04-01

    Full Text Available Results of investigations of wear resistant of two species of cast steel were introduced in the article (low-alloyed and chromium cast steel on the background of the standard material which was low alloy wear resistant steel about the trade name CREUSABRO ®8000. The investigations were executed with two methods: abrasive wears in the stream of loose particles (the stream of quartz sand and abrasive wears particles fixed (abrasive paper with the silicon carbide. Comparing the results of investigations in the experiments was based about the counted wear index which characterizes the wears of the studied material in the relation to the standard material.

  19. Oxidation Resistance of Medium-Carbon Heat-Resistant Cr-Al Steels in Extreme Conditions

    Directory of Open Access Journals (Sweden)

    Mykhail M. Yamshinskij

    2017-10-01

    for development of methodology for forecasting of the special properties of Cr-Al steels depending on their chemical composition is created. Conclusions. Optimal concentration of chrome in heat-resistant Cr steels for work of items at temperatures up to 1100 °C can be considered 25–30 %. To provide high oxidation resistance of items working at temperatures up to 1250 °C in aggressive gas environments, the concentration of Cr in a metal should be within the limits of 25–30 %, and aluminium – from 2.0 to 3.5 %, the relation [% Cr]/[% Al] = 7–10 must be executed. Various gas environments differently effect on oxidation resistance of steels. At the temperatures of 1200 °C items in the water steam environment oxidize faster, and slower in the carbon dioxide environment.

  20. Microstructural evolution and mechanical properties of ODS steel produced by cryogenic milling

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jeoung Han; Kim, Seong Woong; Park, Chan Hee; Yeom, Jong Taek [Korea Institute of Materials Science, Changwon (Korea, Republic of); Lee, Jae Hoon [POSCO Technical Research Laboratories, Gwangyang (Korea, Republic of); Byun, Thak Sang [Materials Science and Technology Division/Oak Ridge National Laboratory, Oak Ridge (United States)

    2013-05-15

    MA is a long-term continuous operation producing a lot of heat. If the heat cannot be discharged in time, it will directly affect the efficiency of milling and quality of resulting powder. The dissolution or amorphization process during MA is believed to be dependent on temperature but still no information is available yet. Since diffusion processes are involved, the formation of expected or unexpected alloy phase can be affected by the temperature of powder and milling media. For example, the degree of solid solubility and the formation of amorphous or nanocrystalline phase may be different according to temperature. Present work is performed to clarify aforementioned issues and design new manufacturing process for advanced ODS steel. To facilitate the experiments, we choose to put very excess amount of Y{sub 2}O{sub 3} (15 wt.%) into Fe-14Cr-3W pre-alloyed powder instead of 0.3 wt.% Y{sub 2}O{sub 3} which is normal content in this kind of system. This is because Y{sub 2}O{sub 3} peak cannot be detected by XRD in the martial which contain such a low amount of Y{sub 2}O{sub 3}. The larger amount of Y{sub 2}O{sub 3} content permits to study the dissolution kinetics and the oxide precipitation by XRD study. To improve the properties of advanced ODS alloy, the effectiveness of cryo milling on the milling behaviour of Y{sub 2}O{sub 3} and Fe-alloy powder was investigated. It was found that resistance to dislocation emission across obstacles did not drop abruptly with temperature rise. TEM observation of the fracture surface of a sliced sample confirmed the occurrence of grain boundary de cohesion at 900 .deg. C and a strain rate of 10{sup -3}s{sup -1}.

  1. NNDSS - Table II. Carbapenemase-producing carbapenem-resistant Enterobacteriaceae

    Data.gov (United States)

    U.S. Department of Health & Human Services — NNDSS - Table II. Carbapenemase-producing carbapenem-resistant Enterobacteriaceae - 2018. In this Table, provisional cases of selected notifiable diseases (≥1,000...

  2. Corrosion resistance of steel fibre reinforced concrete - A literature review

    DEFF Research Database (Denmark)

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

    2017-01-01

    Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of civil infrastructure. However, there are inconsistencies among international standards and guidelines regarding the consideration of carbon-steel fibres for the structural verification of SFRC exposed to corr...

  3. Corrosion-resistant coating for GTE compressor parts made of steels with low tempering temperatures

    Science.gov (United States)

    Muboyadzhyan, S. A.; Egorova, L. P.; Gorlov, D. S.; Bulavintseva, E. E.

    2017-01-01

    The corrosion resistance of an Ni-Co-Cr-Al-Si-Y + SPh (SPh is silicophosphate impregnation) alloy coating on 30Kh13, 38Kh2MYuA, VKS5, and VKS7 structural steels with low tempering temperatures has been studied. The steel-coating compositions have been tested to determine the accelerated cyclic corrosion resistance, the corrosion resistance under tropic climate chamber conditions and in salt fog, the stress corrosion resistance, and the corrosion resistance in an industrial atmosphere. The heat stability of coated samples is studied, metallographic studies of the samples before and after the tests are performed, and the influence of the coating on the strength characteristics of the structural steels is studied.

  4. Nanostructure Formations and Improvement in Corrosion Resistance of Steels by Means of Pulsed Electron Beam Surface Treatment

    Directory of Open Access Journals (Sweden)

    K. M. Zhang

    2013-01-01

    Full Text Available The corrosion of steels has long been the topic for materials scientists. It is established that surface treatment is an efficient way to improve the corrosion resistance of steels without changing the bulk properties and with low costs. In the present paper, different kinds of surface treatment techniques for steels are briefly reviewed. In particular, the surface modification involving nanostructure formations of steels by using a low energy high pulsed electron beam (LEHCPEB treatment is lightened in the case of an AISI 316L stainless steel and D2 steel. The overall results demonstrate the high potential of the LEHCPEB technique for improving the corrosion performance of steels.

  5. Determination of sulfur content in steel by laser-produced plasma atomic emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, A.; Ortiz, M. [Unidad de Fisica Atomica y Laseres, Instituto de Investigacion Basica, CIEMAT, Avda Complutense 22, 28040 Madrid (Spain); Campos, J. [Catedra de Fisica Atomica Experimental, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, 28040 Madrid (Spain)

    1995-11-01

    Sulfur content in steel samples has been determined by laser-produced plasma atomic emission spectroscopy with the use of a Q-switch Nd:YAG laser. With the use of time-resolved spectroscopy employing an OMA III (EG&G) as detector, a detection limit of 70 ppm and a precision of 7{percent} have been obtained. Calibration curves are linear, and no noticeable matrix effects have been observed. {copyright} {ital 1995 Society for Applied Spectroscopy.}

  6. R-Curve Approach to Describe the Fracture Resistance of Tool Steels

    Science.gov (United States)

    Picas, Ingrid; Casellas, Daniel; Llanes, Luis

    2016-06-01

    This work addresses the events involved in the fracture of tool steels, aiming to understand the effect of primary carbides, inclusions, and the metallic matrix on their effective fracture toughness and strength. Microstructurally different steels were investigated. It is found that cracks nucleate on carbides or inclusions at stress values lower than the fracture resistance. It is experimentally evidenced that such cracks exhibit an increasing growth resistance as they progressively extend, i.e., R-curve behavior. Ingot cast steels present a rising R-curve, which implies that the effective toughness developed by small cracks is lower than that determined with long artificial cracks. On the other hand, cracks grow steadily in the powder metallurgy tool steel, yielding as a result a flat R-curve. Accordingly, effective toughness for this material is mostly independent of the crack size. Thus, differences in fracture toughness values measured using short and long cracks must be considered when assessing fracture resistance of tool steels, especially when tool performance is controlled by short cracks. Hence, material selection for tools or development of new steel grades should take into consideration R-curve concepts, in order to avoid unexpected tool failures or to optimize microstructural design of tool steels, respectively.

  7. 76 FR 54209 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2011-08-31

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... conducting an administrative review of the countervailing duty (CVD) order on corrosion-resistant carbon... CORE from Korea with regard to Dongbu and POSCO. See Corrosion-Resistant Carbon Steel Flat Products...

  8. 77 FR 58512 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2012-09-21

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... conducting an administrative review of the countervailing duty (CVD) order on corrosion-resistant carbon... Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Notice of Extension of...

  9. 78 FR 19210 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Final Results of...

    Science.gov (United States)

    2013-03-29

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) has completed its administrative review of the countervailing duty (CVD) order on corrosion-resistant...\\ See Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

  10. Elemental segregation during resistance spot welding of boron containing advanced high strength steels

    NARCIS (Netherlands)

    Amirthalingam, M.; Van der Aa, E.M.; Kwakernaak, C.; Hermans, M.J.M.; Richardson, I.M.

    2015-01-01

    The partitioning behaviour of carbon, phosphorous and boron during the solidification of a resistance spot weld pool was studied using experimental simulations and a phase field model. Steels with varying carbon, phosphorous and boron contents were designed and subjected to a range of resistant spot

  11. Modelling the influence of steel fibres on the electrical resistivity of cementitious composites

    DEFF Research Database (Denmark)

    Solgaard, Anders Ole Stubbe; Michel, Alexander; Stang, Henrik

    2009-01-01

    One of the governing factors on the corrosion of embedded reinforcement is the electrical resistivity of the concrete. The combination of steel fibres and conventional reinforcement bars has been used in a number of structures. However, the addition of electrical con-ductive fibres might influence...... of steel fibre reinforced concrete (SFRC). The parameters investigated in the following are the fibre geometry, the fibre volume and the transitional resistance. On basis of the experimental results, a model, taking the resistivity of the fibres and the concrete matrix into account is proposed....... the overall resistivity of the material and thereby the corrosion rate of the embedded reinforcement. To the knowledge of the authors, only preliminary studies have been made on the influence of corrosion of the reinforcement bars from the addition of the electrical conductive steel fibres. Thus the present...

  12. The comparative studies of ADI versus Hadfield cast steel wear resistance

    Directory of Open Access Journals (Sweden)

    Mieczysław Kaczorowski

    2011-04-01

    Full Text Available The results of comparative studies of wear resistance of ADI versus high manganese Hadfield cast steel are presented. For evaluation ofwear resistance three type of ADI were chosen. Two of them were of moderate strength ADI with 800 and 1000MPa tensile strength whilethe third was 1400MPa tensile strength ADI. The specimens were cut from ADI test YII type casting poured and heat treated in Institute ofFoundry in Krakow. The pin on disc method was used for wear resistance experiment. The specimens had a shape of 40mm long rod withdiameter 6mm. The load and speed were 100N and 0,54m/s respectively. It was concluded that the wear resistance of ADI is comparablewith high manganese cast steel and in case of low tensile grade ADI and is even better for high strength ADI than Hadfield steel.

  13. Microanalysis of two creep resistant 9-12% chromium steels

    Energy Technology Data Exchange (ETDEWEB)

    Haettestrand, M.; Schwind, M.; Andren, H.-O. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Physics

    1998-07-15

    The ferritic chromium steels P122 and P92 have been investigated using APFIM and TEM. The two steels are similar in composition with the exception of an addition of copper to P122, allowing a higher chromium content. The investigated materials were tempered at 770 C and isothermally aged at 600 C for times ranging from 0 to 10000 h. The matrix and precipitates of type M{sub 23}C{sub 6}, MX and Laves phase have been analysed with APFIM. Steel P122 contains 0.9% copper and it was found that the matrix concentration of copper drops during ageing from 0.4% to an equilibrium level at 0.1%, which is in good agreement with previous thermodynamical calculations. No copper was found in M{sub 23}C{sub 6}, MX or Laves phase. Copper instead forms a separate phase. This phase was identified by TEM. During ageing the amount of tungsten in the matrix drops due to formation of Laves phase. This process is faster in steel P122 compared with steel P92, indicating an accelerating effect of copper on the nucleation of Laves phase. In both steels, enhanced concentrations of boron were found inside M{sub 23}C{sub 6} carbides. Phosphorous was found to segregate to a very narrow region at the carbide/matrix interface. (orig.) 18 refs.

  14. Method for reducing formation of electrically resistive layer on ferritic stainless steels

    Science.gov (United States)

    Rakowski, James M.

    2013-09-10

    A method of reducing the formation of electrically resistive scale on a an article comprising a silicon-containing ferritic stainless subjected to oxidizing conditions in service includes, prior to placing the article in service, subjecting the article to conditions under which silica, which includes silicon derived from the steel, forms on a surface of the steel. Optionally, at least a portion of the silica is removed from the surface to placing the article in service. A ferritic stainless steel alloy having a reduced tendency to form silica on at least a surface thereof also is provided. The steel includes a near-surface region that has been depleted of silicon relative to a remainder of the steel.

  15. Characterization of 316L Steel Cellular Dodecahedron Structures Produced by Selective Laser Melting

    Directory of Open Access Journals (Sweden)

    Konda Gokuldoss Prashanth

    2016-10-01

    Full Text Available The compression behavior of different 316L steel cellular dodecahedron structures with different density values were studied. The 316L steel structures produced using the selective laser melting process has four different geometries: single unit cells with and without the addition of base plates beneath and on top, and sandwich structures with multiple unit cells with different unit cell sizes. The relation between the relative compressive strength and the relative density was compared using different Gibson-Ashby models and with other published reports. The different aspects of the deformation and the mechanical properties were evaluated and the deformation at distinct loading levels was recorded. Finite element method (FEM simulations were carried out with the defined structures and the mechanical testing results were compared. The calculated theory, simulation estimation, and the observed experimental results are in good agreement.

  16. Secondary hardening of low-alloyed creep-resistant steel welds

    Directory of Open Access Journals (Sweden)

    P. Mohyla

    2014-01-01

    Full Text Available The T24 steel represents the new generation of low-alloyed creep resistant steels with higher creep resistance and lower carbon content. It was designed as prospective material for membrane waterwalls of ultra super critical (USC power plants, enabling to avoid preheating and post weld heat treatment (PWHT during welding. However, our investigations concerning secondary hardening of vanadium containing low-alloyed steels show that non-tempered welded joints undergo a significant increase in hardness during exposure to operating temperature. The results then imply that PWHT of T24 steel welds is necessary and this idea is at present supported by the occurrence of several troubles with new installations of USC blocks in Europe.

  17. Corrosion-resistant Foamed Cements for Carbon Steels

    Energy Technology Data Exchange (ETDEWEB)

    Sugama T.; Gill, S.; Pyatina, T., Muraca, A.; Keese, R.; Khan, A.; Bour, D.

    2012-12-01

    The cementitious material consisting of Secar #80, Class F fly ash, and sodium silicate designed as an alternative thermal-shock resistant cement for the Enhanced Geothermal System (EGS) wells was treated with cocamidopropyl dimethylamine oxide-based compound as foaming agent (FA) to prepare numerous air bubble-dispersed low density cement slurries of and #61603;1.3 g/cm3. Then, the foamed slurry was modified with acrylic emulsion (AE) as corrosion inhibitor. We detailed the positive effects of the acrylic polymer (AP) in this emulsion on the five different properties of the foamed cement: 1) The hydrothermal stability of the AP in 200 and #61616;C-autoclaved cements; 2) the hydrolysis-hydration reactions of the slurry at 85 and #61616;C; 3) the composition of crystalline phases assembled and the microstructure developed in autoclaved cements; 4) the mechanical behaviors of the autoclaved cements; and, 5) the corrosion mitigation of carbon steel (CS) by the polymer. For the first property, the hydrothermal-catalyzed acid-base interactions between the AP and cement resulted in Ca-or Na-complexed carboxylate derivatives, which led to the improvement of thermal stability of the AP. This interaction also stimulated the cement hydration reactions, enhancing the total heat evolved during cement’s curing. Addition of AP did not alter any of the crystalline phase compositions responsible for the strength of the cement. Furthermore, the AP-modified cement developed the porous microstructure with numerous defect-free cavities of disconnected voids. These effects together contributed to the improvement of compressive-strength and –toughness of the cured cement. AP modification of the cement also offered an improved protection of CS against brine-caused corrosion. There were three major factors governing the corrosion protection: 1) Reducing the extents of infiltration and transportation of corrosive electrolytes through the cement layer deposited on the underlying CS

  18. Improving hardness and wear resistance of austenitic stainless steel; Harte und verschleissfeste Randschicht auf korrosionsbestaendigen Staehlen

    Energy Technology Data Exchange (ETDEWEB)

    Guempel, Paul [Hochschule Konstanz (Germany). Werkstoffprueflabor; Waegner, Martina [Bodycote Hardiff GmbH, Huerth (Germany). S3P-Gruppe

    2010-09-15

    Nowadays more stainless steels are used in the field of automotive technology. These austenitic or ferritic steels have a high corrosion resistance but they are not hardenable and therefore they are susceptible to gallig / fretting during mechanical / tribological loading, for example in connecting rods. With a new surface hardening treatment these detrimental effects can be avoided. Hochschule Konstanz and Bodycote jointly develop this process further to open up new market areas. (orig.)

  19. Nanosized MX Precipitates in Ultra-Low-Carbon Ferritic/Martensitic Heat-Resistant Steels

    Science.gov (United States)

    Yin, Feng-Shi; Jung, Woo-Sang

    2009-02-01

    Nanosized MX precipitates in ultra-low-carbon ferritic/martensitic heat-resistant 9Cr-W-Mo-VNbTiN steels were characterized by transmission electron microscope (TEM) using carbon film replicas. The steels were prepared by vacuum induction melting followed by hot forging and rolling into plates. The plates were normalized at 1100 °C for 1 hour, cooled in air, and tempered at 700 °C for 1 hour. The results show that bimodal nanosized MX precipitates distribute densely and homogeneously in the matrix within martensitic lath after normalizing-and-tempering heat treatment. The larger nanosized MX precipitates with the size of 30 to 50 nm are rich in Nb, while the smaller ones with the size of about 10 nm contain less Nb but more V. Small addition of Ti causes an increase in the number of the larger nanosized MX precipitates. The total number density of the nanosized MX precipitates in the ultra-low-carbon ferritic/martensitic steels is measured to be over 300/ μm2, much higher than that in conventional ferritic/martensitic steels. Short-term creep test results show that the ultra-low-carbon ferritic/martensitic steels with high dense nanosized MX precipitates have much higher creep rupture strength than conventional ASME-P92 steel. The strength degradation of the ultra-low-carbon ferritic/martensitic heat-resistant steels during creep is also discussed in this article.

  20. Microstructure and Abrasive Wear Resistance of 18Cr-4Ni-2.5Mo Cast Steel

    Directory of Open Access Journals (Sweden)

    Kalandyk B.

    2012-12-01

    Full Text Available An influence of a decreased Cr content on the microstructure of the highly alloyed Cr-Ni cast steel, duplex type, melted under laboratory conditions, was characterized in the paper. The microstructure investigations were performed in the initial state and after the heat treatment (solution annealing at 1060°C as well as the phase transformation kinetics at continuous cooling was measured. The wear resistance of the investigated cast steel was tested and compared with the 24%Cr-5%Ni-2.5%Mo cast steel.

  1. Microstructure, phase composition and corrosion resistance of Ni2O3 coatings produced using laser alloying method

    Science.gov (United States)

    Bartkowska, Aneta; Przestacki, Damian; Chwalczuk, Tadeusz

    2016-12-01

    The paper presents the studies' results of microstructure, microhardness, cohesion, phase composition and the corrosion resistance analysis of C45 steel after laser alloying with nickel oxide (Ni2O3). The aim of the laser alloying was to obtain the surface layer with new properties through covering C45 steel by precoat containing modifying compound, and then remelting this precoat using laser beam. As a result of this process the surface layer consisting of remelted zone and heat affected zone was obtained. In the remelted zone an increased amount of modifying elements was observed. It was also found that the surface layer formed during the laser alloying with Ni2O3 was characterized by good corrosion resistance. This property has changed depending on the thickness of the applied precoat. It was observed that the thickness increase of nickel oxides precoat improves corrosion resistance of produced coatings.

  2. Microstructure, phase composition and corrosion resistance of Ni2O3 coatings produced using laser alloying method

    Directory of Open Access Journals (Sweden)

    Bartkowska Aneta

    2016-12-01

    Full Text Available The paper presents the studies' results of microstructure, microhardness, cohesion, phase composition and the corrosion resistance analysis of C45 steel after laser alloying with nickel oxide (Ni2O3. The aim of the laser alloying was to obtain the surface layer with new properties through covering C45 steel by precoat containing modifying compound, and then remelting this precoat using laser beam. As a result of this process the surface layer consisting of remelted zone and heat affected zone was obtained. In the remelted zone an increased amount of modifying elements was observed. It was also found that the surface layer formed during the laser alloying with Ni2O3 was characterized by good corrosion resistance. This property has changed depending on the thickness of the applied precoat. It was observed that the thickness increase of nickel oxides precoat improves corrosion resistance of produced coatings.

  3. Multi objective Taguchi optimization approach for resistance spot welding of cold rolled TWIP steel sheets

    Science.gov (United States)

    Tutar, Mumin; Aydin, Hakan; Bayram, Ali

    2017-08-01

    Formability and energy absorption capability of a steel sheet are highly desirable properties in manufacturing components for automotive applications. TWinning Induced Plastisity (TWIP) steels are, new generation high Mn alloyed steels, attractive for the automotive industry due to its outstanding elongation (%40-45) and tensile strength (~1000MPa). So, TWIP steels provide excellent formability and energy absorption capability. Another required property from the steel sheets is suitability for manufacturing methods such as welding. The use of the steel sheets in the automotive applications inevitably involves welding. Considering that there are 3000-5000 welded spots on a vehicle, it can be interpreted that one of the most important manufacturing method is Resistance Spot Welding (RSW) for the automotive industry. In this study; firstly, TWIP steel sheet were cold rolled to 15% reduction in thickness. Then, the cold rolled TWIP steel sheets were welded with RSW method. The welding parameters (welding current, welding time and electrode force) were optimized for maximizing the peak tensile shear load and minimizing the indentation of the joints using a Taguchi L9 orthogonal array. The effect of welding parameters was also evaluated by examining the signal-to-noise ratio and analysis of variance (ANOVA) results.

  4. Biocompatibly Coated 304 Stainless Steel as Superior Corrosion-Resistant Implant Material to 316L Steel

    Science.gov (United States)

    Paul, Subir; Mandal, Chandranath

    2013-10-01

    Surface treatments of 304 stainless steel by electro-coating and passivating in few inorganic electrolytes were found to be very effective in drastically reducing the corrosion rate of the material in stimulated body fluid (SBF) by several orders in comparison to that of 316L steel, presently being used for orthopedic implants. Polarization studies of electrodeposited hydroxyl apatite coating on 304 steel showed remarkably improved corrosion current. Cyclic polarization of the material in SBF reflected the broadened passivity region, much lower passive current, and narrower hysteresis loops. Similar effects were also found through the formation of inorganic coatings by passivation in NaF, CaNO3, and calcium phosphate buffer solutions. Surface characterization by XRD showed the peaks of the respective coating crystals. The morphology of the coatings studied by SEM showed a flake-type structure for hydroxyapatite coating and fine spherical-subspherical particles for other coatings.

  5. Comparison of Maraging Steel Micro- and Nanostructure Produced Conventionally and by Laser Additive Manufacturing

    Directory of Open Access Journals (Sweden)

    Eric A. Jägle

    2016-12-01

    Full Text Available Maraging steels are used to produce tools by Additive Manufacturing (AM methods such as Laser Metal Deposition (LMD and Selective Laser Melting (SLM. Although it is well established that dense parts can be produced by AM, the influence of the AM process on the microstructure—in particular the content of retained and reversed austenite as well as the nanostructure, especially the precipitate density and chemistry, are not yet explored. Here, we study these features using microhardness measurements, Optical Microscopy, Electron Backscatter Diffraction (EBSD, Energy Dispersive Spectroscopy (EDS, and Atom Probe Tomography (APT in the as-produced state and during ageing heat treatment. We find that due to microsegregation, retained austenite exists in the as-LMD- and as-SLM-produced states but not in the conventionally-produced material. The hardness in the as-LMD-produced state is higher than in the conventionally and SLM-produced materials, however, not in the uppermost layers. By APT, it is confirmed that this is due to early stages of precipitation induced by the cyclic re-heating upon further deposition—i.e., the intrinsic heat treatment associated with LMD. In the peak-aged state, which is reached after a similar time in all materials, the hardness of SLM- and LMD-produced material is slightly lower than in conventionally-produced material due to the presence of retained austenite and reversed austenite formed during ageing.

  6. Metallurgical characteristics and failure mode transition for dissimilar resistance spot welds between ultra-fine grained and coarse-grained low carbon steel sheets

    Energy Technology Data Exchange (ETDEWEB)

    Khodabakhshi, F.; Kazeminezhad, M., E-mail: mkazemi@sharif.edu; Kokabi, A.H.

    2015-06-18

    We studied the microstructure and mechanical characteristics of spot welded specimens, fabricated from low carbon steel sheets with different microstructures. Both ultra-fine grained (UFG) steel sheet and coarse grained (CG) steel sheet were used. The refined microstructure of the UFG steel has been produced by severe plastic deformation (SPD) using the constrained groove pressing (CGP) method. The grain size of the base metals was approximately 260 nm and 30 µm in diameter, respectively, in the UFG and CG steels. Examining the microstructure of a cross section cut through the spot weld reveals a similar grain size and phase distribution in the nugget on both the sides of the initial interface between sheets. Some recrystallization is observed in the heat affected zone on the UFG side as previously reported after the welding of symmetrical UFG–UFG spot welded specimens. The same energy deposit produces larger nuggets after the spot welding of UFG steels. Moreover, the hardness distribution across the nugget changes after welding on both sides of the initial (UFG/CG) interface. This effect is presently attributed to a change in the solidification, cooling rate and tempering after welding, likely because the higher resistance of UFG steel sheets increases the heat release by the Joule effect during spot welding. These changes in the mechanical behavior modify the transition between the interfacial failure (IF) and pull out failure (PF) mode with respect to energy deposit.

  7. Resistance of trip 800 steels in a sour environment containing H{sub 2}S

    Energy Technology Data Exchange (ETDEWEB)

    Sojka, J.; Vodarek, V.; Vanova, P.; Schindler, I.; Wenglorzova, A.; Filus, F. [VSB-TU Ostrava, Faculty of Metallurgy and Materials Engineering, 17. listopadu 15, 708 33, Ostrava (Czech Republic); Kander, L. [Materialovy a metalurgicky vyzkum, s.r.o., Pohranicni 31, 706 02 Ostrava-Vitkovice (Czech Republic)

    2011-07-15

    We have evaluated the resistance of two samples of TRIP 800 steel prepared under laboratory conditions at the Faculty of Metallurgy and Materials Engineering (FMME) VSB (Technical University of Ostrava, Czech Republic) in a sour environment containing H{sub 2}S. The first steel investigated had a C-Mn-Si composition, and the second steel had a C-Mn-Si-Al composition. Both TRIP steels were characterized using the yield strength in the range 420 to 450 MPa and tensile strength in the range 880 to 900 MPa. The TRIP steel samples were in the form of sheets with a thickness of 1.5 mm. The residual austenite content was 11% and 13%, respectively, in the two steels studied. The resistance to hydrogen embrittlement was evaluated in a sour environment that contained hydrogen sulphide using hydrogen-induced cracking (HIC) and sulphide stress cracking (SSC) tests performed in accordance with NACE standards. Both TRIP 800 steels showed a high resistance to hydrogen embrittlement, and no SSC cracks were observed. Some cracking arising from HIC was observed in both steels. The measured parameters showed some variation; in some cases they were lower than recommended limits, but in other cases the measured parameters were higher (e.g., the crack length ratio was up to 70%). The cracks initiated preferentially at non-metallic inclusions, either at elongated manganese sulphide particles, or at oxide stringers that were rich in Al. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. MARTENSITIC CREEP RESISTANT STEEL STRENGTHENED BY Z-PHASE

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention relates to steel alloys having a martensitic or martensitic- ferritic structure and comprising Z-phase (CrXN) particles, where X is one or more of the elements V, Nb, Ta, and where the Z-phase particles have an average size of less than 400 nm. The alloy comprises by wt % th...

  9. Preliminary investigation of steel girder end panel shear resistance.

    Science.gov (United States)

    2010-01-01

    Prior to 1973, steel bridges in California were designed based on Allowable Stress : Design and the shear design of web and transverse stiffeners was based on the : average shear stress in the web. The tension field action equation similar to the : c...

  10. Electrochemical testing of passivity state and corrosion resistance of supermartensitic stainless steels

    Directory of Open Access Journals (Sweden)

    S. Lasek

    2010-01-01

    Full Text Available On low interstitial - supermartensitic stainless steels (X1CrNiMo 12-5-1, X2CrNiMo 13-6-2, X1CrNiMo 12-6-2 the electrochemical potentiodynamic polarization tests were carried out and the passive state stability and localized corrosion resistance were compared and evaluated. The effect of quenching and tempering as well as the changes in microstructure on polarisation curves and corrosion properties at room temperature were established. Small differences in chemical composition of steels were also registered on their corrosion parameters changes and resistance.

  11. Structure dependent resistivity and dielectric characteristics of tantalum oxynitride thin films produced by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Cristea, D., E-mail: daniel.cristea@unitbv.ro [Department of Materials Science, Transilvania University, 500036 Brasov (Romania); Crisan, A. [Department of Materials Science, Transilvania University, 500036 Brasov (Romania); Cretu, N. [Electrical Engineering and Applied Physics Department, Transilvania University, 500036 Brasov (Romania); Borges, J. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710 - 057 Braga (Portugal); Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Lopes, C.; Cunha, L. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710 - 057 Braga (Portugal); Ion, V.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, “Photonic Processing of Advanced Materials” Group, PO Box MG-16, RO 77125 Magurele-Bucharest (Romania); Barradas, N.P. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Apreutesei, M. [MATEIS Laboratory-INSA de Lyon, 21 Avenue Jean Capelle, 69621 Villeurbanne cedex (France); Université de Lyon, Institut des Nanotechnologies de Lyon INL-UMR5270, CNRS, Ecole Centrale de Lyon, Ecully F-69134 (France); Munteanu, D. [Department of Materials Science, Transilvania University, 500036 Brasov (Romania)

    2015-11-01

    Highlights: • Tantalum oxynitride thin films have been deposited by magnetron sputtering, in various configurations. • The rising of the reactive gases mixture flow has the consequence of a gradual increase in the non-metallic content in the films, which results in a 10 orders of magnitude resistivity domain. • The higher resistivity films exhibit dielectric constants up to 41 and quality factors up to 70. - Abstract: The main purpose of this work is to present and to interpret the change of electrical properties of Ta{sub x}N{sub y}O{sub z} thin films, produced by DC reactive magnetron sputtering. Some parameters were varied during deposition: the flow of the reactive gases mixture (N{sub 2} and O{sub 2}, with a constant concentration ratio of 17:3); the substrate voltage bias (grounded, −50 V or −100 V) and the substrate (glass, (1 0 0) Si or high speed steel). The obtained films exhibit significant differences. The variation of the deposition parameters induces variations of the composition, microstructure and morphology. These differences cause variation of the electrical resistivity essentially correlated with the composition and structural changes. The gradual decrease of the Ta concentration in the films induces amorphization and causes a raise of the resistivity. The dielectric characteristics of some of the high resistance Ta{sub x}N{sub y}O{sub z} films were obtained in the samples with a capacitor-like design (deposited onto high speed steel, with gold pads deposited on the dielectric Ta{sub x}N{sub y}O{sub z} films). Some of these films exhibited dielectric constant values higher than those reported for other tantalum based dielectric films.

  12. Blast Resistance of Slurry Infiltrated Fibre Concrete with Waste Steel Fibres from Tires

    Directory of Open Access Journals (Sweden)

    Drdlová Martina

    2018-01-01

    Full Text Available The utilization of waste steel fibres (coming from the recycling process of the old tires in production of blast resistant cement based panels was assessed. Waste fibres were incorporated in slurry infiltrated fibre concrete (SIFCON, which is a special type of ultra-highperformance fibre reinforced concrete with high fibre content. The technological feasibility (i.e. suitability of the waste fibres for SIFCON technology was assessed using homogeneity test. Test specimens were prepared with three volume fractions (5; 7.5 and 10 % by vol. of waste unclassified fibres. SIFCON with industrial steel fibres (10% by vol. and ultra-highperformance fibre concrete with industrial fibres were also cast and tested for comparison purposes. Quasi-static mechanical properties were determined. Real blast tests were performed on the slab specimens (500x500x40 mm according to the modified methodology M-T0-VTU0 10/09. Damage of the slab, the change of the ultrasound wave velocity propagation in the slab specimen before and after the blast load in certain measurement points, the weight of fragments and their damage potential were evaluated and compared. Realized tests confirmed the possibility of using the waste fibres for SIFCON technology. The obtained results indicate, that the usage of waste fibres does not significantly reduce the values of SIFCON flexural and compressive strength at quasi-static load - the values were comparable to the specimens with industrially produced fibres. With increasing fibre content, the mechanical parameters are increasing as well. Using of the waste fibres reduces fragmentation of SIFCON at blast load due to the fibre size parameters. Using of low diameter fibres means more fibres in the matrix and thus better homogeneity of the whole composite with less unreinforced areas. Regarding the blast tests, the specimen with waste steel fibres showed the best resistance and outperformed also the specimen with commercial fibres. Using of

  13. Development of a test method for determining the cracking susceptibility of resistance spot welded high strength steel sheets

    OpenAIRE

    Rethmeier, Michael; Suwala, Hubert

    2014-01-01

    In this study a test method for determining the cracking susceptibility of resistance spot welded high strength steel sheets was investigated. The development of a suitable test procedure is based on the External-Loaded Hot Crack Test (PVC-Test). The test modification for resistance spot welding contains a constant tensile force load. The test method for determining the cracking susceptibility was experimentally verified for a high strength steel, a transformation induced plasticity steel (TR...

  14. 77 FR 25141 - Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea: Extension of Time...

    Science.gov (United States)

    2012-04-27

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From Germany and South Korea... of the antidumping duty (AD) orders on corrosion-resistant carbon steel flat products (CORE) from... Countervailing Duty Operations, Office 3, regarding ``Sunset Reviews of the Antidumping Duty Orders on Corrosion...

  15. 76 FR 69703 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Science.gov (United States)

    2011-11-09

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) published a notice of initiation of the administrative review of the antidumping duty order on corrosion... results of this review. See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of...

  16. 76 FR 4291 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Partial Rescission of...

    Science.gov (United States)

    2011-01-25

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea... administrative review of the countervailing duty order on corrosion- resistant carbon steel flat products from... ] requests for administrative review and partial revocation of the countervailing duty order on corrosion...

  17. 75 FR 77615 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Extension of...

    Science.gov (United States)

    2010-12-13

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) published a notice of initiation of the administrative review of the antidumping duty order on corrosion... results of this review. See Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of...

  18. Effect of Microstructure on Mechanical Properties and Corrosion Resistance of 2205 Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Łabanowski Jerzy

    2015-01-01

    Full Text Available This paper presents results of the research on impact of microstructure of austenitic-ferritic steel of duplex type on its mechanical properties and susceptibility to stress corrosion cracking. As showed, improper processing technologies more and more often used in shipbuilding industry for plates and other half-finished products made of duplex steel may cause significant lowering their properties, which frequently makes their replacing necessary. Results of the tests on stress corrosion under tension with low strain rate (SSRT conducted in an inert and corrosion (boiling magnesium chloride environment, are presented. It was proved that even minor structural transformations taking place in 500°C ageing temperature lower corrosion resistance of the steel. Structural transformations occurring in 700°C temperature to a smaller extent influence susceptibility to stress corrosion of the steel, however they cause drastic drop in its plasticity.

  19. Development of Novel Pre-alloyed PM Steels for Optimization of Machinability and Fatigue Resistance of PM Components

    Science.gov (United States)

    Mardan, Milad; Blais, Carl

    2016-03-01

    It is well known that a large proportion of ferrous PM components require secondary machining operations for dimensional conformance or for producing geometrical features that cannot be generated during die compaction. Nevertheless, the machining behavior of PM parts is generally characterized as being "difficult" due to the presence of residual porosity that lowers thermal conductivity and induces interrupted cutting. Several admixed additives such as MnS and BN-h can be used to improve the machining behavior of PM steels. Nevertheless, their negative effect on mechanical properties, especially fatigue resistance, makes their utilization uninteresting for the fabrication of high-performance PM steel components. This article summarizes the work carried out to develop a novel PM steel that was especially engineered to form machinability enhancing precipitates. This new material is pre-alloyed with tin (Sn) in order to form Cu-Sn (Cu(α)) precipitates during transient liquid phase sintering. The newly developed material presents machinability improvement of 165% compared to reference material used in the PM industry as well as increases in toughness and fatigue resistance of 100% and 13%, respectively.

  20. Pit formation on stainless steel surfaces pre-treated with biosurfactants produced by Pseudomonas fluorescens

    Energy Technology Data Exchange (ETDEWEB)

    Dagbert, Catherine [ECP-LGPM, Grande Voie des Vignes, 92295 Chatenay-Malabry (France)], E-mail: catherine.dagbert@ecp.fr; Meylheuc, Thierry; Bellon-Fontaine, Marie-Noelle [INRA, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France); AGROPARISTECH, UMR 763 Bioadhesion et Hygiene des Materiaux, F-91300 Massy (France)

    2008-12-01

    Today, it is widely established that the surface tension of water can be reduced by some microorganisms capable of synthesizing surface-active compounds called biosurfactants (BS). BS characteristics depend on the microorganism that produces them and therefore, on the microorganism culture conditions. Some studies on chemical surfactants have shown that the adsorption of surface-active compounds plays a major role in corrosion; indeed they are used as a good corrosion inhibition tool. The purpose of this study was first, to estimate the importance and behavior of the stainless steels passive film on the adsorption of BS, produced by the Gram negative bacteria Pseudomonas fluorescens, and secondly, to study the impact of these treatments on the pitting corrosion. In this paper, the galvanostatic polarization technique, used as accelerated method for determining the characteristic pit potentials on stainless steels, is examined. Pit growth, shape and cover formation were also observed. The surface topography of the corroded specimens was investigated using field emission scanning electron microscopy (FESEM)

  1. Stability of MC Carbide Particles Size in Creep Resisting Steels

    Directory of Open Access Journals (Sweden)

    Vodopivec, F.

    2006-01-01

    Full Text Available Theoretical analysis of the dependence microstructure creep rate. Discussion on the effects of carbide particles size and their distribution on the base of accelerated creep tests on a steel X20CrMoV121 tempered at 800 °C. Analysis of the stability of carbide particles size in terms of free energy of formation of the compound. Explanation of the different effect of VC and NbC particles on accelerated creep rate.

  2. Steel Creek primary producers: Periphyton and seston, L-Lake/Steel Creek Biological Monitoring Program, January 1986--December 1991

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, J.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Toole, M.A.; van Duyn, Y. [Normandeau Associates Inc., New Ellenton, SC (United States)

    1992-02-01

    The Savannah River Site (SRS) encompasses 300 sq mi of the Atlantic Coastal Plain in west-central South Carolina. Five major tributaries of the Savannah River -- Upper Three Runs Creek, Four Mile Creek, Pen Branch, Steel Creek, and Lower Three Runs Creek -- drain the site. In 1985, L Lake, a 400-hectare cooling reservoir, was built on the upper reaches of Steel Creek to receive effluent from the restart of L-Reactor and to protect the lower reaches from thermal impacts. The Steel Creek Biological Monitoring Program was designed to assess various components of the system and identify and changes due to the operation of L-Reactor or discharge from L Lake. An intensive ecological assessment program prior to the construction of the lake provided baseline data with which to compare data accumulated after the lake was filled and began discharging into the creek. The Department of Energy must demonstrate that the operation of L-Reactor will not significantly alter the established aquatic ecosystems. This report summarizes the results of six years` data from Steel Creek under the L-Lake/Steel Creek Monitoring Program. L Lake is discussed separately from Steel Creek in Volumes NAI-SR-138 through NAI-SR-143.

  3. MICROSTRUCTURE AND MECHANICAL PROPERTIES DEGRADATION OF CrMo CREEP RESISTANT STEEL OPERATING UNDER CREEP CONDITIONS

    Directory of Open Access Journals (Sweden)

    Ján Micheľ

    2011-07-01

    Full Text Available In this contribution microstructure degradation of a steam tube is analysed. The tube is made of CrMo creep resistant steel and was in service under creep conditions at temperature 530°C and calculated stress level in the tube wall 46.5 MPa. During service life in the steel gradual micro structure changes were observed, first pearlite spheroidization, precipitation, coagulation and precipitate coarsening. Despite the fact that there were evident changes in the micro structure the strength and deformation properties of the steel (Re, Rm, A5, Z, the resistance to brittle fracture and the creep strength limit, were near to unchanged after 2.1x10 5 hours in service. The steam tube is now in service more than 2.6x10 5 h.

  4. Degradation of mechanical properties of CrMo creep resistant steel operating under conditions of creep

    Directory of Open Access Journals (Sweden)

    J. Michel

    2012-01-01

    Full Text Available Mechanical properties of a steam tube made of CrMo creep resistant steel are analysed in this contribution after up to 2,6•105 hours service life in creep conditions at temperature 530 °C and calculated stress level in the tube wall 46,5 MPa. During service life there were in the steel gradual micro structure changes, fi rst pearlite spheroidization, precipitation, coaugulation and precipitate coarsening. Nevertheless the strength and deformation properties of the steel (Re, Rm, A5, Z, and the resistance to brittle fracture and the creep strength limit, were near to unchanged after 2,1•105 hours in service. The steam tube is now in service more than 2,6•105 h.

  5. Torque resistance of different stainless steel wires commonly used for fixed retainers in orthodontics

    DEFF Research Database (Denmark)

    Arnold, Dario; Dalstra, Michel; Verna, Carlalberta

    2016-01-01

    retainers in orthodontics. Materials and Methods: Torquing moments acting on a retainer wire were measured in a mechanical force testing system by applying buccal crown torque to an upper lateral incisor in both a 3-teeth and in a 2-teeth setup. Seven stainless steel wires with different shape, type (plain......Objective: Movements of teeth splinted by fixed retention wires after orthodontic treatment have been observed. The aetiological factors for these movements are unknown. The aim of this in vitro study was to compare the resistance to torque of different stainless steel wires commonly used for fixed...... or a braided 0.016 × 0.022-inch stainless steel wire. A tooth attached by a retainer wire to only one neighbouring tooth is less resistant to torque than a tooth connected to two neighbouring teeth. Annealing a retainer wire with a flame reduces the stiffness of the wire markedly and can lead to a non...

  6. Effect of Cu and Ni on Corrosion Resistance of Low Alloyed Steels for Cargo Oil Tank

    Science.gov (United States)

    Xiaobing, Luo; Feng, Chai; Hang, Su; Caifu, Yang; Hao, Li; Yaqing, Hou; Zhengyan, Zhang

    The corrosion behavior of four kinds of low alloyed steels in acid chloride solution (10%NaCl, pH=0.85) was studied on the basis of International Maritime Organization(IMO) standard. Results indicated that, with the increase of Cu and Ni content in steels, the corrosion rate exhibited a law of linear decline, polarization curve moved to positive direction, corrosion potential raised, current density significantly decreased and the interface electric resistance obviously increased. The mechanism of improvement the corrosion resistance of Cu bearing steel can be mainly attributed to the Cu enrichment on the surface of rust layer by means of re-deposition particles(100 500 nm) and keeping high stability. However, Ni was not found in the rust layer but improved the corrosion potential of matrix.

  7. Microstructure of Al-Si Slurry Coatings on Austenitic High-Temperature Creep Resisting Cast Steel

    Directory of Open Access Journals (Sweden)

    Agnieszka E. Kochmańska

    2018-01-01

    Full Text Available This paper presents the results of microstructural examinations on slurry aluminide coatings using scanning electron microscopy, X-ray microanalysis, and X-ray diffraction. Aluminide coatings were produced in air atmosphere on austenitic high-temperature creep resisting cast steel. The function of aluminide coatings is the protection of the equipment components against the high-temperature corrosion in a carburising atmosphere under thermal shock conditions. The obtained coatings had a multilayered structure composed of intermetallic compounds. The composition of newly developed slurry was powders of aluminium and silicon; NaCl, KCl, and NaF halide salts; and a water solution of a soluble glass as an inorganic binder. The application of the inorganic binder in the slurry allowed to produce the coatings in one single step without additional annealing at an intermediate temperature as it is when applied organic binder. The coatings were formed on both: the ground surface and on the raw cast surface. The main technological parameters were temperature (732–1068°C and time of annealing (3.3–11.7 h and the Al/Si ratio (4–14 in the slurry. The rotatable design was used to evaluate the effect of the production parameters on the coatings thickness. The correlation between the technological parameters and the coating structure was determined.

  8. Corrosion resistance of premodeled wires made of stainless steel used for heart electrotherapy leaders

    Science.gov (United States)

    Przondziono, J.; Walke, W.; Młynarski, R.; Szatka, W.

    2012-05-01

    The purpose of the study is to evaluate resistance to electrochemical corrosion of wire made of X10CrNi18-8 stainless steel designed for use in cardiology treatment. The influence of strain formed in the premodeling process and methods of wire surface preparation to corrosive resistance in artificial plasma solution were analysed. Wire corrosion tests were carried out in the solution of artificial plasma. Resistance to electrochemical corrosion was evaluated on the ground of recorded curves of anodic polarization by means of potentiodynamic method. Potentiodynamic tests carried out enabled to determine how the resistance to pitting corrosion of wire changes, depending on strain formed in the premodeling process as well as on the method of wire surface preparation. For evaluation of phenomena occurring on the surface of tested steel, electrochemical impedance spectroscopy (EIS) was applied. Deterioration of corrosive properties of wire along with the increase in the formed strain hardening was observed.

  9. Effect of tungsten addition on high-temperature properties and microstructure of alumina-forming austenitic heat-resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Min-Ho [Division of Materials Science and Engineering, Hanyang University, Seongdong-ku, Seoul 133-791 (Korea, Republic of); Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Moon, Joonoh; Kang, Jun-Yun; Ha, Heon-Young [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Choi, Baig Gyu [High Temperature Materials Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Lee, Tae-Ho [Ferrous Alloy Department, Advanced Metallic Materials Division, Korea Institute of Materials Science, 797 Changwondaero, Seongsangu, Changwon, Gyeongnam 642-831 (Korea, Republic of); Lee, Changhee, E-mail: chlee@hanyang.ac.kr [Division of Materials Science and Engineering, Hanyang University, Seongdong-ku, Seoul 133-791 (Korea, Republic of)

    2015-10-28

    High-temperature tensile and creep properties of W-added Alumina-Forming austenitic (AFA{sub W}) heat-resistant steel were investigated as compared with AFA steel without W. High-temperature tensile properties of two steels were similar to each other, but creep lifetime of AFA{sub W} steel was increased. Microstructural examination using SEM and TEM revealed that creep rate rapidly decreased when Laves phase initially precipitated. This indicated that the precipitation of Laves phase played an important role in hardening of AFA steel. It is also found that AFA{sub W} steel exhibited finer and denser Laves phase compared with AFA steel, which is due to partial substitution of W for Mo. The finer and denser distribution of Laves phase contributed to improved creep properties of AFA{sub W} steel by enhancement in precipitation hardening.

  10. Mechanical behavior and failure mechanism of resistance spot welded DP1000 dual phase steel

    NARCIS (Netherlands)

    Chabok, A.; Van der Aa, Ellen; de Hosson, J.T.M.; Pei, Y.T.

    2017-01-01

    This paper reports on the microstructural evolution of resistance spot welded 1000 MPa dual phase steel under two different welding conditions, and their relation to the mechanical performance and failure mechanisms. It is shown that a double pulse weld scheme leads to an enhancement in

  11. The Effect of Microstructure on the Abrasion Resistance of Low Alloyed Steels

    NARCIS (Netherlands)

    Xu, X.

    2016-01-01

    The thesis attempts to develop advanced high abrasion resistant steels with low hardness in combination with good toughness, processability and low alloying additions. For this purpose, a novel multi-pass dual-indenter (MPDI) scratch test approach has been developed to approach the real continuous

  12. Recent advances in creep-resistant steels for power plant applications

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    Interaction of Steels with Hydrogen in Petroleum Industry. Pressure Vessel and Pipeline Service (New York: Mater. Properties Council) vol. 2, pp 607–618. Czyrska-Filemonowicz A, Penkalla H J, Zielinska-Lipiec A, Ennis P J 2001 Proc. 9th Int. Conf. on. Creep Resistant Metallic Materials, Prague, (ed.) J Purmensky, pp 204– ...

  13. Computational design of heat resistant steels with evolving and time-independent strengthening factors

    NARCIS (Netherlands)

    Lu, Q.

    2015-01-01

    Alloy design by the traditional trial and error approach is known to be a time consuming and a highly cost procedure, especially for the design of heat resistant steel where the feedback time is intrinsically long. The significant developments in computational simulation techniques in the last

  14. PRODUCTION OF POROUS POWDER MATERIALS OF SPHERICAL POWDERS OF CORROSION-RESISTANT STEEL

    Directory of Open Access Journals (Sweden)

    V. N. Kovalevskij

    2012-01-01

    Full Text Available Production of porous powder materials from spherical powders of corrosion-resistant steel 12Х18н10Т with formation at low pressures 120–140 mpa in the mold with the subsequent activated sintering became possible due to increase of duration of process of spattering and formation of condensate particles (Si–C or (Mo–Si on surface.

  15. Steel corrosion resistance in model solutions and reinforced mortar containing wastes

    NARCIS (Netherlands)

    Koleva, D.A.; Van Breugel, K.

    2012-01-01

    This work reports on the corrosion resistance of steel in alkaline model solutions and in cement-based materials (mortar). The model solutions and the mortar specimens were Ordinary Portland Cement (OPC) based. Further, hereby discussed is the implementation of an eco-friendly approach of waste

  16. Use of Direct Current Resistivity Measurements to Assess AISI 304 Austenitic Stainless Steel Sensitization

    OpenAIRE

    Mesquita, Ramaiany Carneiro; Mecury, José Manoel Rivas; Tanaka, Auro Atsumi; Sousa, Regina Célia de

    2015-01-01

    This paper describes the feasibility of using direct current electrical resistivity measurements to evaluate AISI 304 austenitic stainless steel sensitization. ASTM A262 – Practice A and double loop electrochemical potentiodynamic reactivation (DL-EPR) tests were performed to assess the degree of sensitization (DoS) qualitatively and quantitatively, and electrical resistivity (ER) was measured by the four-point direct-current potential drop method. The results indicate that the DoS incr...

  17. Development of 3D modeling technology for manufacturing finned ribbons from heat-resistant steels

    Science.gov (United States)

    Lyashkov, A. A.; Vasil'ev, E. V.; Popov, A. Y.

    2017-06-01

    The process of shaping a workpiece by a tool using the rolling method is, from the geometric point of view, a process of interaction of two conjugate surfaces. The technology of rolling finned stainless steel ribbons is close to the technology of shaping details by cutting. However, the problems of its practical implementation in the well-known papers analyzing this issue are practically not considered. As a result of the analysis of conjugate surfaces profiling methods in relation to the problem, it was concluded that it seems urgent to develop a methodology for the formation of corrugated ribbon based on 3D modeling use. The implementation of this methodology includes the creation of solid models of the product and the tool, as well as computer simulation of their shaping processes using rolling method. So, at the first stage, a 3D model of finned ribbon was developed, which was then used to produce a profile of a rolling tool. The modeling of this profile was carried out on the basis of the proposed software package in the CAD environment. The created theoretical model of the tool profile was replaced from the technological point of view by a rectilinear profile. To carry out the analysis of the obtained results, the inverse shaping problem was solved - according to the corrected profile of the tool, real profile of the corrugated ribbon is obtained. Computer modeling of extruded volumes in the process of shaping was performed. The analysis of qualitative and quantitative parameters of the extruded volumes made it possible to give recommendations on setting the increment of the tool motion parameter. Based on the results of the studies, profile parameters of the roller are assigned for its practical implementation. The proposed methodology, based on 3D-modeling, allowed to develop a technology for manufacturing finned ribbons from heat-resistant steels by rolling with high productivity, accuracy and stability of the sizes obtained.

  18. 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.

  19. Influence of silver additions to type 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance

    DEFF Research Database (Denmark)

    Chiang, Wen-Chi; Tseng, I-Sheng; Møller, Per

    2010-01-01

    techniques. The microstructure of these 316 stainless steels was examined, and the influences of silver additions to 316 stainless steels on bacterial inhibition, mechanical properties, and corrosion resistance were investigated. This study suggested that silver-bearing 316 stainless steels could be used......Bacterial contamination is a major concern in many areas. In this study, silver was added to type 316 stainless steels in order to obtain an expected bacteria inhibiting property to reduce the occurrence of bacterial contamination. Silver-bearing 316 stainless steels were prepared by vacuum melting...

  20. Impact of the nanostructuration on the corrosion resistance and hardness of irradiated 316 austenitic stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Hug, E., E-mail: eric.hug@ensicaen.fr [Laboratoire de Cristallographie et Sciences des Matériaux, Normandie Université, CNRS UMR 6508, 6 Bd Maréchal Juin, 14050 Caen (France); Prasath Babu, R. [School of Materials, University of Manchester, M13 9PL (United Kingdom); Groupe de Physique des Matériaux, UMR CNRS 6634, Université et INSA de Rouen, Normandie Université, Saint-Etienne du Rouvray Cedex (France); Monnet, I. [Centre de recherches sur les Ions, les Matériaux et la Photonique CEA-CNRS, Normandie Université, 6 Bd Maréchal Juin, 14050 Caen (France); Etienne, A. [Groupe de Physique des Matériaux, UMR CNRS 6634, Université et INSA de Rouen, Normandie Université, Saint-Etienne du Rouvray Cedex (France); Moisy, F. [Centre de recherches sur les Ions, les Matériaux et la Photonique CEA-CNRS, Normandie Université, 6 Bd Maréchal Juin, 14050 Caen (France); Pralong, V. [Laboratoire de Cristallographie et Sciences des Matériaux, Normandie Université, CNRS UMR 6508, 6 Bd Maréchal Juin, 14050 Caen (France); Enikeev, N. [Institute of Physics of Advanced Materials, Ufa (Russian Federation); Saint Petersburg State University, Laboratory of the Mechanics of Bulk Nanostructured Materials, 198504 St. Petersburg (Russian Federation); Abramova, M. [Institute of Physics of Advanced Materials, Ufa (Russian Federation); and others

    2017-01-15

    Highlights: • Impacts of nanostructuration and irradiation on the properties of 316 stainless steels are reported. • Irradiation of nanostructured samples implies chromium depletion as than depicted in coarse grain specimens. • Hardness of nanocrystalline steels is only weakly affected by irradiation. • Corrosion resistance of the nanostructured and irradiated samples is less affected by the chromium depletion. - Abstract: The influence of grain size and irradiation defects on the mechanical behavior and the corrosion resistance of a 316 stainless steel have been investigated. Nanostructured samples were obtained by severe plastic deformation using high pressure torsion. Both coarse grain and nanostructured samples were irradiated with 10 MeV {sup 56}Fe{sup 5+} ions. Microstructures were characterized using transmission electron microscopy and atom probe tomography. Surface mechanical properties were evaluated thanks to hardness measurements and the corrosion resistance was studied in chloride environment. Nanostructuration by high pressure torsion followed by annealing leads to enrichment in chromium at grain boundaries. However, irradiation of nanostructured samples implies a chromium depletion of the same order than depicted in coarse grain specimens but without metallurgical damage like segregated dislocation loops or clusters. Potentiodynamic polarization tests highlight a definitive deterioration of the corrosion resistance of coarse grain steel with irradiation. Downsizing the grain to a few hundred of nanometers enhances the corrosion resistance of irradiated samples, despite the fact that the hardness of nanocrystalline austenitic steel is only weakly affected by irradiation. These new experimental results are discussed in the basis of couplings between mechanical and electrical properties of the passivated layer thanks to impedance spectroscopy measurements, hardness properties of the surfaces and local microstructure evolutions.

  1. Micro/nano engineering on stainless steel substrates to produce superhydrophobic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Beckford, Samuel; Zou Min, E-mail: mzou@uark.edu

    2011-12-30

    Creating micro-/nano-scale topography on material surfaces to change their wetting properties has been a subject of much interest in recent years. Wenzel in 1936 and Cassie and Baxter in 1944 proposed that by microscopically increasing the surface roughness of a substrate, it is possible to increase its hydrophobicity. This paper reports the fabrication of micro-textured surfaces and nano-textured surfaces, and the combination of both on stainless steel substrates by sandblasting, thermal evaporation of aluminum, and aluminum-induced crystallization (AIC) of amorphous silicon (a-Si). Meanwhile, fluorinated carbon films were used to change the chemical composition of the surfaces to render the surfaces more hydrophobic. These surface modifications were investigated to create superhydrophobic surfaces on stainless steel substrates. The topography resulting from these surface modifications was analyzed by scanning electron microscopy and surface profilometry. The wetting properties of these surfaces were characterized by water contact angle measurement. The results of this study show that superhydrophobic surfaces can be produced by either micro-scale surface texturing or nano-scale surface texturing, or the combination of both, after fluorinated carbon film deposition.

  2. Achieving a Carbon Neutral Society without Industry Contraction in the Five Major Steel Producing Countries

    Directory of Open Access Journals (Sweden)

    Kyunsuk Choi

    2016-05-01

    Full Text Available This study analyzed the direct and indirect CO2 emissions of the energy-intensive basic metals industry, in particular steels, using the distributions of various energy sources, including coal/peat, oil, and electricity, from an input–output table. An analysis of five major steel producing countries indicated that direct CO2 emissions increased 1.4-fold and that indirect CO2 emissions increased by more than two-fold between 1995 and 2010. The elasticity of the CO2 emissions and the total energy costs indicated that Korea, Japan, and Germany are sensitive to energy sources from the electric power industry, whereas China and the US are more sensitive to energy sources pertaining to the coal and oil industry. Using the available forest area and photosynthesis, the potential neutralization ability of CO2 was estimated using the eco-CO2 index. The US yielded the highest CO2 neutralization ability of 66.1%, whereas Korea yielded a CO2 neutralization ability of 15%. Future trends of the 2030 eco-CO2 index revealed China and Korea will rapidly lose their neutralization ability resulting in a net negative neutralization ability if left unabated. The significant decline in the eco-CO2 index for the basic metals industry may be inhibited by utilizing bamboo wood charcoal for pulverized coal injection (PCI in the steelmaking process.

  3. Corrosion Resistance and Pitting Behaviour of Low-Carbon High-Mn Steels in Chloride Solution

    Directory of Open Access Journals (Sweden)

    Grajcar A.

    2016-06-01

    Full Text Available Corrosion resistance of the X4MnSiAlNbTi27-4-2 and X6MnSiAlNbTi26-3-3 type austenitic steels, after hot deformation as well as after cold rolling, were evaluated in 3.5% NaCl solution using potentiodynamic polarization tests. A type of nonmetallic inclusions and their pitting corrosion behaviour were investigated. Additionally, the effect of cold deformation on the corrosion resistance of high-Mn steels was studied. The SEM micrographs revealed that corrosion damage formed in both investigated steels is characterized by various shapes and an irregular distribution at the metallic matrix, independently on the steel state (thermomechanically treated or cold worked. Corrosion pits are generated both in grain interiors, grain boundaries and along the deformation bands. Moreover, corrosion damage is stronger in cold deformed steels in comparison to the thermomechanically treated specimens. EDS analysis revealed that corrosion pits preferentially nucleated on MnS and AlN inclusions or complex oxysulphides. The morphology of corrosion damage in 3.5% NaCl supports the data registered in potentiodynamic tests.

  4. Influence of Sulfur Content on the Corrosion Resistance of 17-4PH Stainless Steel

    Science.gov (United States)

    Tavares, S. S. M.; Pardal, J. M.; Martins, T. R. B.; da Silva, M. R.

    2017-04-01

    According to specification standards, the basic chemical composition of steel 17-4PH for special and critical applications is 15-17% Cr, 3.0-5.0% Ni, 3.0-5.0% Cu, 0.07% C (max) and 0.15-0.45% (Nb + Ta) (wt.%). The maximum sulfur content is 0.030%. However, as it will be shown in this work, this maximum limit for sulfur is too high for services where high corrosion resistance is necessary. Two samples of 17-4PH steel with similar base compositions, but quite different sulfur contents (0.027% and 0.001%S), were compared with respect to pitting corrosion and sensitization. Both materials were heat treated according to commercial treatments A, H900, H1100, H1150 and H1150D (ASTM A-1082). Two corrosion tests were applied to compare the steels. The first one was the double-loop electrochemical potentiodynamic reactivation (DL-EPR) test in 0.25 M H2SO4 + 0.01 KSCN solution, which is used to measure the degree of sensitization. The second test was the anodic polarization in 3.5%NaCl solution, commonly used to evaluate the pitting corrosion resistance. Detailed microstructural characterization by magnetic measurements, light optical and scanning electron microscopy was performed. As main conclusion, despite that both steels have chemical compositions in accordance with the standards, the steel with higher sulfur was much more susceptible to pitting and sensitization.

  5. The Influence of Laser Surface Alloying on the Thermal Fatigue Resistance of Hot Work Tool Steels

    Directory of Open Access Journals (Sweden)

    Jonda E.

    2016-09-01

    Full Text Available The paper presents results of the effect of laser surface remelting and alloying by carbides powders of NbC, TaC, TiC, VC and WC on the structure and thermal fatigue resistance of the surface layer of hot work tool steels X40CrMoV5-1 and 32CrMoV12-28. The laser surface alloying and remelting treatments was performed using a high power diode laser (HPDL ROFIN SINAR DL 020. In order to investigate the effect of applied laser treatments and used alloying powders on the microstructure and thermal fatigue resistance of processed surface layer of hot work tool steels, the microstructure evaluation by light microscopy, hardness test, and dedicated thermal fatigue resistance test were performed. The best results regarding fatigue cracks inhibition was obtained when the surface of hot work tool steels was alloyed with TiC and VC carbides at the laser beam power of 2.0 and 2.3 kW. The grain refinement effect of laser remelting has a lower impact on the thermal crack inhibition, than a strong strengthening effect of matrix saturation in alloying elements and precipitation of fine carbides in the steel matrix.

  6. In vitro corrosion resistance of Lotus-type porous Ni-free stainless steels.

    Science.gov (United States)

    Alvarez, Kelly; Hyun, Soong-Keun; Fujimoto, Shinji; Nakajima, Hideo

    2008-11-01

    The corrosion behavior of three kinds of austenitic high nitrogen Lotus-type porous Ni-free stainless steels was examined in acellular simulated body fluid solutions and compared with type AISI 316L stainless steel. The corrosion resistance was evaluated by electrochemical techniques, the analysis of released metal ions was performed by inductively coupled plasma mass spectrometry (ICP-MS) and the cytotoxicity was investigated in a culture of murine osteoblasts cells. Total immunity to localized corrosion in simulated body fluid (SBF) solutions was exhibited by Lotus-type porous Ni-free stainless steels, while Lotus-type porous AISI 316L showed very low pitting corrosion resistance evidenced by pitting corrosion at a very low breakdown potential. Additionally, Lotus-type porous Ni-free stainless steels showed a quite low metal ion release in SBF solutions. Furthermore, cell culture studies showed that the fabricated materials were non-cytotoxic to mouse osteoblasts cell line. On the basis of these results, it can be concluded that the investigated alloys are biocompatible and corrosion resistant and a promising material for biomedical applications.

  7. Mechanical properties and oxidation and corrosion resistance of reduced-chromium 304 stainless steel alloys

    Science.gov (United States)

    Stephens, J. R.; Barrett, C. A.; Gyorgak, C. A.

    1979-01-01

    An experimental program was undertaken to identify effective substitutes for part of the Cr in 304 stainless steel as a method of conserving the strategic element Cr. Although special emphasis was placed on tensile properties, oxidation and corrosion resistance were also examined. Results indicate that over the temperature range of -196 C to 540 C the yield stress of experimental austenitic alloys with only 12 percent Cr compare favorably with the 18 percent Cr in 304 stainless steel. Oxidation resistance and in most cases corrosion resistance for the experimental alloys were comparable to the commercial alloy. Effective substitutes for Cr included Al, Mo, Si, Ti, and V, while Ni and Mn contents were increased to maintain an austenitic structure.

  8. Histamine-producing Lactobacillus parabuchneri strains isolated from grated cheese can form biofilms on stainless steel.

    Science.gov (United States)

    Diaz, Maria; Del Rio, Beatriz; Sanchez-Llana, Esther; Ladero, Victor; Redruello, Begoña; Fernández, María; Martin, M Cruz; Alvarez, Miguel A

    2016-10-01

    The consumption of food containing large amounts of histamine can lead to histamine poisoning. Cheese is one of the most frequently involved foods. Histamine, one of the biogenic amines (BAs) exhibiting the highest safety risk, accumulates in food contaminated by microorganisms with histidine decarboxylase activity. The origin of these microorganisms may be very diverse with contamination likely occurring during post-ripening processing, but the microorganisms involved during this manufacturing step have never been identified. The present work reports the isolation of 21 histamine-producing Lactobacillus parabuchneri strains from a histamine-containing grated cheese. PCR revealed that every isolate carried the histidine decarboxylase gene (hdcA). Eight lineages were identified based on the results of genome PFGE restriction analysis plus endonuclease restriction profile analysis of the carried plasmids. Members of all lineages were able to form biofilms on polystyrene and stainless steel surfaces. L. parabuchneri is therefore an undesirable species in the dairy industry; the biofilms it can produce on food processing equipment represent a reservoir of histamine-producing bacteria and thus a source of contamination of post-ripening-processed cheeses. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Dissemination of antibiotic resistance genes from antibiotic producers to pathogens

    DEFF Research Database (Denmark)

    Jiang, Xinglin; Ellabaan, Mostafa M Hashim; Charusanti, Pep

    2017-01-01

    , that appear to be closely related to actinobacterial ARGs known to confer resistance against clinically important antibiotics. Furthermore, we identify two potential examples of recent horizontal transfer of actinobacterial ARGs to proteobacterial pathogens. Based on this bioinformatic evidence, we propose......It has been hypothesized that some antibiotic resistance genes (ARGs) found in pathogenic bacteria derive from antibiotic-producing actinobacteria. Here we provide bioinformatic and experimental evidence supporting this hypothesis. We identify genes in proteobacteria, including some pathogens...... and experimentally test a 'carry-back' mechanism for the transfer, involving conjugative transfer of a carrier sequence from proteobacteria to actinobacteria, recombination of the carrier sequence with the actinobacterial ARG, followed by natural transformation of proteobacteria with the carrier-sandwiched ARG. Our...

  10. Influence of thermal spraying parameters on the corrosion resistance of aluminium oxide coatings deposited on steel 1020

    Science.gov (United States)

    Salas, Y.; Vera, E.; Moreno, M.; Pineda, Y.

    2016-02-01

    Parameters required for the preparation of coatings of aluminium oxide deposited on AISI 1020 steels were determined according to their thickness and type of flame to differentiate their behaviour against corrosion. Commercial powders were used by the method of thermal spraying deposition. The coatings were analysed by OM (optical microscopy), the thickness was measured by means of a coating thickness gauge and electrochemical techniques variables measured was the Linear Polarization Resistance (LPR) and approximation Tafel potentiodynamic curves. The corrosion current for steel 1020 with Na2SO4 electrolyte of 3.5% is of the order of hundreds of A/cm2 and coated steel given in the order of A/cm2, which leads to think that the projection produces coatings uniform low closed porosity, although techniques DC indicate a significant porosity as is observable current response to the potentiodynamic curve. The observed thicknesses fall into the hundreds of microns and little uniformity was noted in this coatings. The coatings deposited by oxidizing flame was better performance in corrosion than the coating deposited by neutral flame.

  11. Corrosion resistance of PANi-coated steel in simulated PEMFC anodic environment

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Naibao; Liang, Chenghao [Electromechanics and Materials Engineering College, Dalian Maritime University, Dalian 116026 (China); Yi, Baolian [Fuel Cell R and D Center, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2008-01-15

    By using electrochemical techniques, the corrosion resistance of polyaniline (PANi)-coated 1Cr18Ni9Ti stainless steel was investigated in simulated proton exchange membrane fuel cell (PEMFC) anodic environment. The results indicated that the compact conductive PANi film could be obtained on 1Cr18Ni9Ti steel by pulse potentiostatic method (PPSM). When steel was coated with conductive PANi, its corrosion potential was improved from -350 to 250 mV in simulated corrosion solution. During the potentiostatic polarization in PEMFC's anodic operation environment, the film is stable and there is no degradation of the PANi film. The film has no effect on the performance of the fuel cell. Further effort to improve the performance of conductive polymer coatings and to estimate the long-term performance in actual PEMFC environment is desirable. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

  12. Impact of the nanostructuration on the corrosion resistance and hardness of irradiated 316 austenitic stainless steels

    Science.gov (United States)

    Hug, E.; Prasath Babu, R.; Monnet, I.; Etienne, A.; Moisy, F.; Pralong, V.; Enikeev, N.; Abramova, M.; Sauvage, X.; Radiguet, B.

    2017-01-01

    The influence of grain size and irradiation defects on the mechanical behavior and the corrosion resistance of a 316 stainless steel have been investigated. Nanostructured samples were obtained by severe plastic deformation using high pressure torsion. Both coarse grain and nanostructured samples were irradiated with 10 MeV 56Fe5+ ions. Microstructures were characterized using transmission electron microscopy and atom probe tomography. Surface mechanical properties were evaluated thanks to hardness measurements and the corrosion resistance was studied in chloride environment. Nanostructuration by high pressure torsion followed by annealing leads to enrichment in chromium at grain boundaries. However, irradiation of nanostructured samples implies a chromium depletion of the same order than depicted in coarse grain specimens but without metallurgical damage like segregated dislocation loops or clusters. Potentiodynamic polarization tests highlight a definitive deterioration of the corrosion resistance of coarse grain steel with irradiation. Downsizing the grain to a few hundred of nanometers enhances the corrosion resistance of irradiated samples, despite the fact that the hardness of nanocrystalline austenitic steel is only weakly affected by irradiation. These new experimental results are discussed in the basis of couplings between mechanical and electrical properties of the passivated layer thanks to impedance spectroscopy measurements, hardness properties of the surfaces and local microstructure evolutions.

  13. Vibration analysis of resistance spot welding joint for dissimilar plate structure (mild steel 1010 and stainless steel 304)

    Science.gov (United States)

    Sani, M. S. M.; Nazri, N. A.; Alawi, D. A. J.

    2017-09-01

    Resistance spot welding (RSW) is a proficient joining method commonly used for sheet metal joining and become one of the oldest spot welding processes use in industry especially in the automotive. RSW involves the application of heat and pressure without neglecting time taken when joining two or more metal sheets at a localized area which is claimed as the most efficient welding process in metal fabrication. The purpose of this project is to perform model updating of RSW plate structure between mild steel 1010 and stainless steel 304. In order to do the updating, normal mode finite element analysis (FEA) and experimental modal analysis (EMA) have been carried out. Result shows that the discrepancies of natural frequency between FEA and EMA are below than 10 %. Sensitivity model updating is evaluated in order to make sure which parameters are influences in this structural dynamic modification. Young’s modulus and density both materials are indicate significant parameters to do model updating. As a conclusion, after perform model updating, total average error of dissimilar RSW plate is improved significantly.

  14. Study on wear resistant cast B-containing 1Cr18Ni9Ti stainless steel

    Directory of Open Access Journals (Sweden)

    Kuang Jiacai

    2009-02-01

    Full Text Available The developed 1Cr18Ni9Ti austenitic stainless steel containing 1.63 wt.%B have been characterized by X-ray diffraction (XRD, electron probe microanalyzer (EPMA, optical microscopy (OM, scanning electron microscopy (SEM, energy dispersive X-ray spectroscopy (EDS and Vickers microhardness measurement. The microstructural evolution and property of high boron stainless steel after solution treatment at the temperature of 1050℃ are also investigated. The results show that the main compositions of borides are Fe, Cr and B, and with small amount of Ni, Mn and C elements. Silicon is insoluble in the borides. The hardness of borides is over 1,500 HV. It has been found that borides do not decompose during solution treatment, but part of borides dissolves into the matrix. The effect of increasing the solubility of boron element in the austenitic matrix favours the hardness enhancement by 8.54%. High boron stainless steel has excellent wear resistance in corrosive environment. Lifetime of transfer pipe made of high boron-containing stainless steel is 1.5-1.8 times longer than that of boron-free 1Cr18Ni9Ti stainless steel.

  15. Characterisation of Wear Resistant Boride Layers on a Tool Steel by Activity Controlled Pack Boronising

    DEFF Research Database (Denmark)

    Fernandes, Frederico Augusto Pires; Christiansen, Thomas Lundin; Somers, Marcel A. J.

    2015-01-01

    The present work addresses the production and characterisation of iron boride layers by pack boronising of a Vanadis 6 tool steel. The boride layers were produced at 900°C for 2h using different pack compositions in order to obtain a single-phase boride layer. The layers were characterized by ele...

  16. Atomic-scale decoration for improving the pitting corrosion resistance of austenitic stainless steels

    Science.gov (United States)

    Zhou, Y. T.; Zhang, B.; Zheng, S. J.; Wang, J.; San, X. Y.; Ma, X. L.

    2014-01-01

    Stainless steels are susceptible to the localized pitting corrosion that leads to a huge loss to our society. Studies in the past decades confirmed that the pitting events generally originate from the local dissolution in MnS inclusions which are more or less ubiquitous in stainless steels. Although a recent study indicated that endogenous MnCr2O4 nano-octahedra within the MnS medium give rise to local nano-galvanic cells which are responsible for the preferential dissolution of MnS, effective solutions of restraining the cells from viewpoint of electrochemistry are being tantalizingly searched. Here we report such a galvanic corrosion can be greatly resisted via bathing the steels in Cu2+-containing solutions. This chemical bath generates Cu2−δS layers on the surfaces of MnS inclusions, invalidating the nano-galvanic cells. Our study provides a low-cost approach via an atomic scale decoration to improve the pitting corrosion resistance of stainless steels in a volume-treated manner. PMID:24398863

  17. Stochastic analysis of the lateral-torsional buckling resistance of steel beams with random imperfections

    Science.gov (United States)

    Kala, Zdeněk

    2013-10-01

    The paper deals with the statistical analysis of resistance of a hot-rolled steel IPE beam under major axis bending. The lateral-torsional buckling stability problem of imperfect beam is described. The influence of bending moments and warping torsion on the ultimate limit state of the IPE beam with random imperfections is analyzed. The resistance is calculated by means of the close form solution. The initial geometrical imperfections of the beam are considered as the formatively identical to the first eigen mode of buckling. Changes of mean values of the resistance, of mean values of internal bending moments, of the variance of resistance and of the variance of internal bending moments were studied in dependence on the beam non-dimensional slenderness. The values of non-dimensional slenderness for which the statistical characteristics of internal moments associated with random resistance are maximal were determined.

  18. Behaviour of fibre reinforced concrete using steel slag coarse aggregate produced in Qatar

    OpenAIRE

    Alnahhal Wael

    2017-01-01

    The state of Qatar suffers from the shortage of natural resources needed for concrete production. Therefore, it is essential to investigate the feasibility of using by-product recycled materials as aggregates to maintain the concrete construction industry. Several types of recyclable materials are currently used in concrete. One of the potential resources of recycled concrete is steel slag. Knowing that Steel slag is the most significant solid waste generated by Qatar Steel Company in Qatar, ...

  19. Pathogen resistance of transgenic tobacco plants producing caffeine.

    Science.gov (United States)

    Kim, Yun-Soo; Sano, Hiroshi

    2008-02-01

    Caffeine (1,3,7-trimethylxanthine) is a typical purine alkaloid, and produced by a variety of plants such as coffee and tea. Its physiological function, however, is not completely understood, but chemical defense against pathogens and herbivores, and allelopathic effects against competing plant species have been proposed. Previously, we constructed transgenic tobacco plants, which produced caffeine up to 5 microg per gram fresh weight of leaves, and showed them to repel caterpillars of tobacco cutworms (Spodoptera litura). In the present study, we found that these transgenic plants constitutively expressed defense-related genes encoding pathogenesis-related (PR)-1a and proteinase inhibitor II under non-stressed conditions. We also found that they were highly resistant against pathogens, tobacco mosaic virus and Pseudomonas syringae. Expression of PR-1a and PR-2 was higher in transgenic plants than in wild-type plants during infection. Exogenously applied caffeine to wild-type tobacco leaves exhibited the similar resistant activity. These results suggested that caffeine stimulated endogenous defense system of host plants through directly or indirectly activating gene expression. This assumption is essentially consistent with the idea of chemical defense, in which caffeine may act as one of signaling molecules to activate defense response. It is thus conceivable that the effect of caffeine is bifunctional; direct interference with pest metabolic pathways, and activation of host defense systems.

  20. Characterization of Microstructure and Mechanical Properties of Resistance Spot Welded DP600 Steel

    Directory of Open Access Journals (Sweden)

    Ali Ramazani

    2015-09-01

    Full Text Available Resistance spot welding (RSW as a predominant welding technique used for joining steels in automotive applications needs to be studied carefully in order to improve the mechanical properties of the spot welds. The objectives of the present work are to characterize the resistance spot weldment of DP600 sheet steels. The mechanical properties of the welded joints were evaluated using tensile-shear and cross-tensile tests. The time-temperature evolution during the welding cycle was measured. The microstructures observed in different sites of the welds were correlated to thermal history recorded by thermocouples in the corresponding areas. It was found that cracks initiated in the periphery region of weld nuggets with a martensitic microstructure and a pull-out failure mode was observed. It was also concluded that tempering during RSW was the main reason for hardness decrease in HAZ.

  1. Aluminide protective coatings on high–temperature creep resistant cast steel

    Directory of Open Access Journals (Sweden)

    J. Kubicki

    2009-10-01

    Full Text Available This paper presents the results of research on aluminide protective coatings manufactured on high–temperature creep resistant cast steel. The main purpose of these coatings is protection against the high temperature corrosion, especially at high carburizing potential atmosphere. Coatings were obtained on cast steel type G–XNiCrSi36–18 with the following methods: pack cementation, paste method, cast method and slurry cementation. The phase composition, thickness and morphology of coatings were determined. Coatings capacity of carbon diffusion inhibition and thermal shocks resistance of coatings were determined with different methods. It was found, that all of the coatings reduce carbon diffusion in different degree and all coatings liable to degradation in consequence cracking and oxidation. Coating life time is mainly dependent on morphology, phase composition and service condition (thermal shocks first of all.

  2. THIN-WALLED CROSS SECTION SHAPE INFLUENCE ON STEEL MEMBER RESISTANCE

    Directory of Open Access Journals (Sweden)

    Elżbieta Urbańska-Galewska

    2016-03-01

    Full Text Available This work describes why trending thin-walled technology is achieving popularity in steel construction sector. A purpose of this article is to present the influence of the cold-formed element cross-section shape on an axial compression and a bending moment resistance. The authors have considered four different shapes assuming constant section area and thickness. Calculations were based on three different steel grades taking into account local, distortional and overall buckling. The results are presented in a tabular and a graphical way and clearly confirm that cross-section forming distinctly impact the cold-formed member resistance. The authors choose these cross-sections that work better in compression state and the other (those slender and high that function more efficiently are subjected to bending.

  3. Antibacterial properties and corrosion resistance of AISI 420 stainless steels implanted by silver and copper ions

    Science.gov (United States)

    Ni, Hong-wei; Zhang, Han-shuang; Chen, Rong-sheng; Zhan, Wei-ting; Huo, Kai-fu; Zuo, Zhen-yu

    2012-04-01

    Silver or copper ions are often chosen as antibacterial agents. But a few reports are concerned with these two antibacterial agents for preparation of antibacterial stainless steel (SS). The antibacterial properties and corrosion resistance of AISI 420 stainless steel implanted by silver and copper ions were investigated. Due to the cooperative antibacterial effect of silver and copper ions, the Ag/Cu implanted SS showed excellent antibacterial activities against both Gram-negative Escherichia coli ( E. coli) and Gram-positive Staphylococcus aureus ( S. aureus) at a total implantation dose of 2×1017 ions/cm2. Electrochemical polarization curves revealed that the corrosion resistance of Ag/Cu implanted SS was slightly enhanced as compared with that of un-implanted SS. The implanted layer was characterized by X-ray photoelectron spectroscopy (XPS). Core level XPS spectra indicate that the implanted silver and copper ions exist in metallic state in the implanted layer.

  4. Standard guide for estimating the atmospheric corrosion resistance of low-alloy steels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 This guide presents two methods for estimating the atmospheric corrosion resistance of low-alloy weathering steels, such as those described in Specifications A242/A242M, A588/A588M, A606 Type 4, A709/A709M grades 50W, HPS 70W, and 100W, A852/A852M, and A871/A871M. One method gives an estimate of the long-term thickness loss of a steel at a specific site based on results of short-term tests. The other gives an estimate of relative corrosion resistance based on chemical composition. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.

  5. Effects of erodant particle shape and various heat treatments on erosion resistance of plain carbon steel

    Science.gov (United States)

    Salik, J.; Buckley, D. H.

    1981-01-01

    Erosion tests were conducted on 1045 steel samples which had been subjected to different heat treatments. The weight of material removed upon erosion with glass beads and crushed glass was measured. The data show that there is no correlation between hardness and erosion resistance. The erosion rate was strongly dependent on the shape of erodant particles, being an order of magnitude higher for erosion with crushed glass than with glass beads. Heat treatment had a profound effect on the erosion resistance when the erodant particles were glass beads but little or no effect when the particles were crushed glass. It is thus concluded that different mechanisms of material removal are involved with these two erodants. This conclusion is supported by the surface morphology of annealed 1045 steel samples which had been eroded by these two types of erodant particles. SEM micrographs of the eroded surfaces show that for erosion with glass beads it is deformation induced fracture of surface layers.

  6. 77 FR 27438 - Certain Corrosion-Resistant Carbon Steel Flat Products From Korea: Final Results of Expedited...

    Science.gov (United States)

    2012-05-10

    ... International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From Korea: Final... third five-year sunset review of the countervailing duty order on certain corrosion-resistant carbon..., plated, or coated with corrosion-resistant metals such as zinc, aluminum, or zinc-, aluminum-, nickel- or...

  7. Behaviour of fibre reinforced concrete using steel slag coarse aggregate produced in Qatar

    Directory of Open Access Journals (Sweden)

    Alnahhal Wael

    2017-01-01

    Full Text Available The state of Qatar suffers from the shortage of natural resources needed for concrete production. Therefore, it is essential to investigate the feasibility of using by-product recycled materials as aggregates to maintain the concrete construction industry. Several types of recyclable materials are currently used in concrete. One of the potential resources of recycled concrete is steel slag. Knowing that Steel slag is the most significant solid waste generated by Qatar Steel Company in Qatar, replacing of natural coarse aggregate with steel slag aggregate will have a significant environmental and economic impact to the state of Qatar. This paper presents the compression and flexural test results of different concrete mixes made of steel slag coarse aggregate combined with a newly developed basalt chopped fibres. The parameters investigated included the volume fraction of the fibre used and the type of coarse aggregates (natural aggregates “Gabbro” and steel slag aggregates. Plain concrete specimens containing natural coarse aggregates and steel slag aggregates with no fibres added were also tested to serve as control. Test results showed that adding the basalt chopped fibres to the concrete mixes enhanced their flexural tensile strengths at different percentages. In addition, the compressive strength of concrete made with steel slag aggregate was higher than that made with natural gabbro aggregate. Test results clearly showed that steel slag aggregates can be used as sustainable and eco-friendly alternative materials in concrete structures.

  8. 77 FR 67395 - Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Revised Schedule for the...

    Science.gov (United States)

    2012-11-09

    ... From the Federal Register Online via the Government Publishing Office INTERNATIONAL TRADE COMMISSION Corrosion-Resistant Carbon Steel Flat Products From Germany and Korea; Revised Schedule for the Subject Reviews AGENCY: United States International Trade Commission. ACTION: Notice. DATES: Effective...

  9. Developing and Studying the Methods of Hard-Facing with Heat-Resisting High-Hardness Steels

    Science.gov (United States)

    Malushin, N. N.; Kovalev, A. P.; Valuev, D. V.; Shats, E. A.; Borovikov, I. F.

    2016-08-01

    The authors develop the methods of hard-facing of mining-metallurgic equipment parts with heat-resisting high-hardness steels on the base of plasma-jet hard-facing in the shielding-alloying nitrogen atmosphere.

  10. Corrosion resistance and development length of steel reinforcement with cementitious coatings

    Science.gov (United States)

    Pei, Xiaofei

    This research program focused on the corrosion resistance and development length of reinforcing steel coated with Cementitious Capillary Crystalline Waterproofing (CCCW) materials. The first part of this research program involved using the half-cell potential method to evaluate the corrosion resistance of CCCW coating materials. One hundred and two steel bars were embedded in concrete cylinders and monitored. In total, 64 steel reinforcing bars were coated with CCCW prior to embedment, 16 mortar cylinders were externally coated with CCCW, and 22 control (uncoated) samples were tested. All the samples were immersed in a 3.5% concentration chloride solution for a period of one year. Three coating types were studied: CCCW-B, CCCW-B+ C and CCCW-C+D. The test results showed that the CCCW coating materials delayed the corrosion activity to varying degrees. In particular, CCCW-C+D applied on the reinforcing steel surface dramatically delayed the corrosion activity when compared to the control samples. After being exposed to the chloride solution for a period of one year, no sign of corrosion was observed for the cylinders where the concrete surface was coated. The second part of this research evaluated the bond strength and development length of reinforcing steel coated with two types of CCCW coating materials (CCCW-B+C and CCCW-C+D) using a modified pull-out test method. A self-reacting inverted T-shaped beam was designed to avoid compression in the concrete surrounding the reinforcing steel. Steel reinforcing bars were embedded along the web portion of the T-beam with various embedded lengths and were staggered side by side. In total, six T-beams were fabricated and each beam contained 8 samples. Both short-term (7 days) and long-term (3 months) effects of water curing were evaluated. The reinforcing steel bars coated with CCCW-B+C demonstrated a higher bond strength than did samples coated with CCCW-C+D. However, the bond strengths of samples with coating materials

  11. Plasma immersion ion implantation on 15-5PH stainless steel: influence on fatigue strength and wear resistance

    Science.gov (United States)

    Bonora, R.; Cioffi, M. O. H.; Voorwald, H. J. C.

    2017-05-01

    Surface improvement in steels is of great interest for applications in industry. The aim of this investigation is to study the effect of nitrogen ion implantation on the axial fatigue strength and wear resistance of 15-5 PH stainless steel. It is well know that electroplated coatings, which are used to improve abrasive wear and corrosion properties, affects negatively the fatigue strength. It is also important to consider requirements to reduce the use of coated materials with electroplated chromium and cadmium, that produce waste, which is harmful to health and environment. The HVOF (High velocity oxygen fuel) process provides hardness, wear strength and higher fatigue resistance in comparison to electroplated chromium. Plasma immersion ion implantation has been used to enhance the hardness, wear, fatigue and corrosion properties of metals and alloys. In the present research the fatigue life increased twice for 15-5 PH three hours PIII treated in comparison to base material. From the abrasive wear tests a lower pin mass reduction was observed, associated to the superficial treatments. The improvement of fatigue and mechanical performance is attributed to a combination of nitrides phase structure and compressive residual stresses during the PIII treatment.

  12. The thermal fatigue behaviour of creep-resistant Ni-Cr cast steel

    Directory of Open Access Journals (Sweden)

    B. Piekarski

    2007-12-01

    Full Text Available The study gives a summary of the results of industrial and laboratory investigations regarding an assessment of the thermal fatigue behaviour of creep-resistant austenitic cast steel. The first part of the study was devoted to the problem of textural stresses forming in castings during service, indicating them as a cause of crack formation and propagation. Stresses are forming in carbides and in matrix surrounding these carbides due to considerable differences in the values of the coefficients of thermal expansion of these phases. The second part of the study shows the results of investigations carried out to assess the effect of carbon, chromium and nickel on crack resistance of austenitic cast steel. As a criterion of assessment the amount and propagation rate of cracks forming in the specimens as a result of rapid heating followed by cooling in running water was adopted. Tests were carried out on specimens made from 11 alloys. The chemical composition of these alloys was comprised in a range of the following values: (wt-%: 18-40 %Ni, 17-30 %Cr, 1.2-1.6%Si and 0.05-0.6 %C. The specimens were subjected to 75 cycles of heating to a temperature of 900oC followed by cooling in running water. After every 15 cycles the number of the cracks was counted and their length was measured. The results of the measurements were mathematically processed. It has been proved that the main factor responsible for an increase in the number of cracks is carbon content in the alloy. In general assessment of the results of investigations, the predominant role of carbon and of chromium in the next place in shaping the crack behaviour of creep-resistant austenitic cast steel should be stressed. Attention was also drawn to the effect of high-temperature corrosion as a factor definitely deteriorating the cast steel resistance to thermal fatigue.

  13. MECHANIZM OF ANODE DISSOLVING OF CORROSION-RESISTING AND STRUCTURAL CARBON STEELS UNDER ELECTROPULSE POLISHING

    Directory of Open Access Journals (Sweden)

    N. P. Ivanova

    2013-01-01

    Full Text Available In this article were suggested the schemes of anode processes, taking into account the nature of metals, anion structure, pH solution of electrolyte and anode potential by electropulse polishing of corrosion- resisting and structural carbon steels.It is shown and experimentally confirmed, that under conditions of electropulse polishing of anode dissolving of metals, which are contained into corrosion-resisting and structural carbon steels, carried out according to mechanism of complex formation through a set of series and series-parallel of intermediate stages. In the 1st stage on the surface of metals adsorption complexes with participation of chemisorption molecules of water are formed. In the next stages anions of electrolyte’s solution and molecules of water take part. In final stage of dissolving on the surface of anode soluble compounds are formed, which by transition into solution into simple ions are dissociated. It is determined that by electrical-impulse polishing in dissolving of components of corrosion-resisting carbon steels the important role play chemical processes, and anode dissolving of metals take place in the field of mixed electrochemical and diffusion kinetics . Diffusion limitations appear as a result of difficult ion mass transfer through surface salt, oxide and hydro-oxide and absorption-phase coatings.

  14. Effect of reinforcing steel debonding on RC frame performance in resisting progressive collapse

    Directory of Open Access Journals (Sweden)

    Waleed Mohamed Elsayed

    2016-12-01

    Full Text Available This paper presents the experimental program performed to study the effect of reinforcing steel debonding on progressive collapse resistance of moment resisting frame designed and detailed in accordance with the Egyptian code provisions for seismic design. Half-scale specimens of the first story were extracted from the frame structure prototype. Each specimen represented a two-bay beam resulting from the removal of middle supporting column of the lower floor. In all specimens, the exterior two short columns were restrained against horizontal and vertical displacements and a monotonic vertical load was applied on the middle column stub to simulate the vertical load of the upper stories. Gradually increasing vertical load at the location of the removed column is continuously applied and increased up to failure. The cracking patterns, strains and the deformations at selected locations of reinforcing steel and concrete are recorded for further analysis. Different debonded reinforcement ratios, places and length are examined in this study to evaluate its effect on the collapse resistance performance of the frame. The effect of debonding on the distribution of reinforcing steel strain is evaluated. The nonlinear response of the frame to the removal of the column is evaluated and the amount of energy absorbed during the course of deformation is calculated.

  15. Significance of steel electrical resistance method in the evaluation of reinforcement corrosion in cementitious systems

    Directory of Open Access Journals (Sweden)

    Krajci, L.

    2004-06-01

    Full Text Available The suitable detection system of steel reinforcement corrosion in concrete structures contributes to the reduction of their maintenance costs. Method of steel electrical resistance represents non-destructive monitoring of steel in cementitious systems. Specially prepared and arranged test specimen of steel as a corrosion sensor is embedded in mortar specimen. Verification tests of this method based on chloride corrosion of steel in mortars as well as its visual inspection are introduced. Significance of steel electrical resistance method lies in the expression of steel corrosion by these quantitative parameters: reduction of cross-section of steel, thickness of corroded layer and loss of weight of steel material. This method is an integral method that allows the indirect determination of mentioned corrosion characteristics. The comparison of verified method with gravimetric evaluation of steel corrosion gives a good correspondence. Test results on mortars with calcium chloride dosages between 0.5% and 4.0% by weight of cement prove high sensitiveness and reliability of steel electrical resistance method.

    La utilización de un sistema de detección de la corrosión de las armaduras en estructuras de hormigón puede contribuir a la reducción de sus costes de mantenimiento. El método de la resistencia eléctrica del acero consiste en la monitorización no-destructiva realizada sobre el acero en sistemas cementantes. Dentro de la muestra de mortero se coloca el sistema de detección, especialmente preparado y fijado, actuando como un sensor de la corrosión. En este trabajo se presentan ensayos de verificación de este método, junto con inspecciones visuales, en morteros sometidos a corrosión de armaduras por efecto de los cloruros. La efectividad de este método de la resistencia eléctrica del acero se expresa, en la corrosión de armaduras, de acuerdo a los siguientes parámetros cuantitativos: reducción de la sección transversal del

  16. Efficiency of protective coatings on high creep resistant cast steel

    Directory of Open Access Journals (Sweden)

    J. Kubicki

    2009-04-01

    Full Text Available This paper presents results of research of multilayer aluminium–silicon coatings. Aluminium–silicon coatings were created on high–temperature creep resist cast iron using slurry method in air atmosphere. These coatings protect equipment against hot corrosionin carburizing atmosphere at thermal shocks conditions.Various technological parameters of coatings manufacturing were applied. Main technological parameters were: temperature and time ofannealing and Al-Si ratio in the active mixture. The structure of obtained coatings is three-zonal. Phase composition of two external zones ensures protection against carburizing, but these zones are not resistant to cracking. The cracks form as a result of thermal shocks. The internal zone of the coatings situated next to substrate compensates for differences of thermal expansion of the coating and the substrate. The cracks are stopped in the internal zone and do not propagate into the substrate material. Protective efficiency of the coatings at carburizing conditions with thermal shocks was determined. Structure of the coatings before and after carburizing and thermal shocks is described in present paper. Thickness, chemical composition (EDS and phase composition (XRD of the coatings are determined. Correlation between the coatings structure and depth of carburized layer was determined.

  17. Heat resistance of Fe-Al intermetallics in the context of selected heat-resistant and hihg-temperature creep resistant steels

    Directory of Open Access Journals (Sweden)

    P. Baranowski

    2009-04-01

    Full Text Available Results are hereby presented of heat-resistance tests of two Fe3Al and FeAl intermetallic phase-based alloys in the context of St41k-typeboiler steel and 50H21G9N4 high-temperature creep resistant steel. It has been ascertained that heat resistance of the 50H21G9N4 steeland of the Fe3Al and FeAl intermetallic phase-based alloys significantly exceeds that of the boiler steel tested in the air atmosphere and the atmosphere of a flue gas with CO, CO2, SiO2 content alike. Improvement of these properties depends of exposure conditions. The largest differences have been observed when the tests were carried out in temperature 1023 K and in the flue gas atmosphere. The differences have been more and more noticeable as the exposition duration extended. A tendency has been also recorded of smaller mass decrements of the Fe3Al and FeAl intermetallic phase-based alloys as compared to the 50H21G9N4 steel.

  18. Resistance Spot Welding of Aluminum Alloy to Steel with Transition Material - From Process to Performance

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Xin; Stephens, Elizabeth V.; Khaleel, Mohammad A.; Shao, H; Kimchi, Menachem; Menachem Kimchi and Wanda Newman

    2004-05-11

    This paper summarizes work to date on resistance spot welding (RSW) of aluminum alloy to mild steel from process development to performance evaluation. A cold-rolled strip material is introduced as a transition material to aid the resistance welding process. The optimal welding parameters and electrode selections were established using a combination of experimental and analytical approaches. The mechanical behaviors of welded samples was evaluated using static and dynamic strength tests and cyclic fatigue tests. A statistical analysis was also performed to analyze the effect of different failure modes on the sample's peak load and energy absorption.

  19. Resistance spot welding of galvanized steel: Part II. Mechanisms of spot weld nugget formation

    Science.gov (United States)

    Gedeon, S. A.; Eagar, T. W.

    1986-12-01

    Dynamic inspection monitoring of the weld current, voltage, resistance, electrode displacement, and force was performed in conjunction with a detailed study of the effects of material variations and weld process parameter modifications on resistance spot welding of coated and uncoated steels. In order to determine the mechanisms of weld nugget formation and growth, scanning electron microscopy photos were taken of the developing nugget. These physical changes were then related to the dynamic inspection curves and the welding current lobe. The effects of material variations and weld process modifications, the results of which were presented in Part I, can be explained through an understanding of these mechanisms.

  20. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhe [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); Yu, Ting [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States); School of Mechanical and Electrical Engineering, Nanchang University, Nanchang, Jiangxi 330031 (China); Kovacevic, Radovan, E-mail: kovacevi@smu.edu [Center for Laser-aided Manufacturing, Lyle School of Engineering, Southern Methodist University, 3101 Dyer Street, Dallas, TX 75206 (United States)

    2017-07-15

    Highlights: • The coatings of 420 stainless steel reinforced with VC were fabricated by high power direct diode laser. • The erosion resistance of the cladded layer was increased with the increase in the VC fraction. • No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. • The corrosion resistance of the cladded layer was decreased with the increase in the VC fraction. - Abstract: Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%–40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V{sub 8}C{sub 7}, M{sub 7}C{sub 3}, and M{sub 23}C{sub 6} were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content

  1. Investigation of the Microstructural, Mechanical and Corrosion Properties of Grade A Ship Steel-Duplex Stainless Steel Composites Produced via Explosive Welding

    Science.gov (United States)

    Kaya, Yakup; Kahraman, Nizamettin; Durgutlu, Ahmet; Gülenç, Behçet

    2017-08-01

    Grade A ship-building steel-AISI 2304 duplex stainless steel composite plates were manufactured via explosive welding. The AISI 2304 plates were used to clad the Grade A plates. Optical microscopy studies were conducted on the joining interface for characterization of the manufactured composite plates. Notch impact, tensile-shear, microhardness, bending and twisting tests were carried out to determine the mechanical properties of the composites. In addition, the surfaces of fractured samples were examined by scanning electron microscopy (SEM), and neutral salt spray (NSS) and potentiodynamic polarization tests were performed to examine corrosion behavior. Near the explosion zone, the interface was completely flat, but became wavy as the distance from the explosion zone increased. The notch impact tests indicated that the impact strength of the composites decreased with increasing distance from the explosion zone. The SEM studies detected brittle behavior below the impact transition temperature and ductile behavior above this temperature. Microhardness tests revealed that the hardness values increased with increasing distance from the explosion zone and mechanical tests showed that no visible cracking or separation had occurred on the joining interface. The NSS and potentiodynamic polarization tests determined that the AISI 2304 exhibited higher corrosion resistance than the Grade A steel.

  2. Fire resistance of single pitched-roof steel portal frame

    Directory of Open Access Journals (Sweden)

    J. J. Ferrán Gozálvez

    2017-03-01

    Full Text Available The standard procedure of structural fire design is based on the simplified analysis of single members. This method leads to conservative results in the case of structures able to redistribution of forces. The failure mechanism affecting both life safety and fire propagation is unknown. This work proposes a methodology for the advanced fire calculation of single pitched-roof portal frame for an agroindustrial building according to the Spanish Specifications with the structural software SAP2000. A non-linear dynamic and plastic, geometric (P-Delta and large-displacements calculation method has been developed. The different failure mechanisms and their influence are studied in terms of fire time resistance, human hazard and good safety. Also, parametric analyses were conducted: load level, rotational stiffness of the base and finally, support fire protection.

  3. CO{sub 2} corrosion resistance of carbon steel in relation with microstructure changes

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa, Nathalie, E-mail: nochoa@usb.ve [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Vega, Carlos [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Pébère, Nadine; Lacaze, Jacques [Université de Toulouse, CIRIMAT, UPS/INPT/CNRS, ENSIACET, 4 Allée Emile Monso, CS 44362, 31030 Toulouse Cedex 4 (France); Brito, Joaquín L. [Laboratorio de Físico-química de Superficies, Centro de Química, Instituto Venezolano de Investigaciones Cientificas (IVIC), Carretera Panamericana, Km 11, Altos de Pipe, Estado Miranda (Venezuela, Bolivarian Republic of)

    2015-04-15

    The microstructural effects on the corrosion resistance of an API 5L X42 carbon steel in 0.5 M NaCl solution saturated with CO{sub 2} was investigated. Four microstructures were considered: banded (B), normalized (N), quenched and tempered (Q&T), and annealed (A). Electrochemical measurements (polarization curves and electrochemical impedance spectroscopy) were coupled with surface analyses (scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS)) to characterize the formation of the corrosion product layers. Electrochemical results revealed that corrosion resistance increased in the following order: B < N < Q&T < A. From the polarization curves it was shown that specifically, cathodic current densities were affected by microstructural changes. SEM images indicated that ferrite dissolved earlier than cementite and a thin layer of corrosion products was deposited on the steel surface. XPS analyses revealed that this layer was composed of a mixture of iron carbonate and non-dissolved cementite. It was also found that the quantity of FeCO{sub 3} content on the steel surface was greater for Q&T and A microstructures. These results, in agreement with the electrochemical data, indicate that the deposition mechanism of iron carbonate is closely related to the morphology of the non-dissolved cementite, determining the protective properties of the corrosion product layers. - Highlights: • The effect of change in microstructure on CO{sub 2} corrosion resistance was evaluated. • An API 5LX 42 carbon steel was immersed in a 0.5 M NaCl solution saturated with CO{sub 2}. • Banded, normalized, quenched-tempered and annealed microstructures were considered. • Electrochemical measurements were coupled with surface analysis. • Morphology and distribution of undissolved Fe{sub 3}C control corrosion kinetics.

  4. Erosion and corrosion resistance of laser cladded AISI 420 stainless steel reinforced with VC

    Science.gov (United States)

    Zhang, Zhe; Yu, Ting; Kovacevic, Radovan

    2017-07-01

    Metal Matrix Composites (MMC) fabricated by the laser cladding process have been widely applied as protective coatings in industries to improve the wear, erosion, and corrosion resistance of components and prolong their service life. In this study, the AISI 420/VC metal matrix composites with different weight percentage (0 wt.%-40 wt.%) of Vanadium Carbide (VC) were fabricated on a mild steel A36 by a high power direct diode laser. An induction heater was used to preheat the substrate in order to avoid cracks during the cladding process. The effect of carbide content on the microstructure, elements distribution, phases, and microhardness was investigated in detail. The erosion resistance of the coatings was tested by using the abrasive waterjet (AWJ) cutting machine. The corrosion resistance of the coatings was studied utilizing potentiodynamic polarization. The results showed that the surface roughness and crack susceptibility of the laser cladded layer were increased with the increase in VC fraction. The volume fraction of the precipitated carbides was increased with the increase in the VC content. The phases of the coating without VC consisted of martensite and austenite. New phases such as precipitated VC, V8C7, M7C3, and M23C6 were formed when the primary VC was added. The microhardness of the clads was increased with the increase in VC. The erosion resistance of the cladded layer was improved after the introduction of VC. The erosion resistance was increased with the increase in the VC content. No obvious improvement of erosion resistance was observed when the VC fraction was above 30 wt.%. The corrosion resistance of the clads was decreased with the increase in the VC content, demonstrating the negative effect of VC on the corrosion resistance of AISI 420 stainless steel

  5. The effect of tempering temperature on pitting corrosion resistance of 420 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Anwar, Moch Syaiful, E-mail: moch026@lipi.go.id; Prifiharni, Siska, E-mail: sisk002@lipi.go.id; Mabruri, Efendi, E-mail: effe004@lipi.go.id [Research Center for Metallurgy and Materials – Indonesian Institute of Sciences (LIPI) Kawasan PUSPIPTEK Building 470 – South of Tangerang – Banten – 15314 (Indonesia)

    2016-04-19

    The AISI Type 420 stainless steels are commonly used to steam generators, mixer blades, etc. These stainless steels are most prone to pitting in dissolved Cl{sup −} containing environments. In this paper, the effect of tempering temperature on pitting corrosion resistance of AISI Type 420 stainless steels was studied. The AISI Type 420 stainless steels specimens were heat treated at the temperature of 1050°C for 1 hour to reach austenite stabilization and then quench in the oil. After that, the specimens were tempered at the temperature of 150, 250, 350 and 450°C for 30 minutes and then air cooled to the room temperature. The electrochemical potentiodynamic polarization test was conducted at 3.5% sodium chloride solution to evaluate corrosion rate and pitting corrosion behaviour. The Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) were used to evaluate the pitting corrosion product. The result have shown that highest pitting potential was found in the sample tempered at 250°C and corrosion pits were found to initiate preferentially around chromium carbides.

  6. Effect of Plasma Nitriding Process Conditions on Corrosion Resistance of 440B Martensitic Stainless Steel

    Directory of Open Access Journals (Sweden)

    Łępicka Magdalena

    2014-09-01

    Full Text Available Martensitic stainless steels are used in a large number of various industrial applications, e.g. molds for plastic injections and glass moldings, automotive components, cutting tools, surgical and dental instruments. The improvement of their tribological and corrosion properties is a problem of high interest especially in medical applications, where patient safety becomes a priority. The paper covers findings from plasma nitrided AISI 440B (PN-EN or DIN X90CrMoV18 stainless steel corrosion resistance studies. Conventionally heat treated and plasma nitrided in N2:H2 reaction gas mixture (50:50, 65:35 and 80:20, respectively in two different temperature ranges (380 or 450°C specimens groups were examined. Microscopic observations and electrochemical corrosion tests were performed using a variety of analytical techniques. As obtained findings show, plasma nitriding of AISI 440B stainless steel, regardless of the process temperature, results in reduction of corrosion current density. Nevertheless, applying thermo-chemical process which requires exceeding temperature of about 400°C is not recommended due to increased risk of steel sensitization to intergranular and stress corrosion. According to the results, material ion nitrided in 450°C underwent leaching corrosion processes, which led to significant disproportion in chemical composition of the corroded and corrosion-free areas. The authors suggest further research into corrosion process of plasma nitrided materials and its degradation products.

  7. The effect of tempering temperature on pitting corrosion resistance of 420 stainless steels

    Science.gov (United States)

    Anwar, Moch. Syaiful; Prifiharni, Siska; Mabruri, Efendi

    2016-04-01

    The AISI Type 420 stainless steels are commonly used to steam generators, mixer blades, etc. These stainless steels are most prone to pitting in dissolved Cl- containing environments. In this paper, the effect of tempering temperature on pitting corrosion resistance of AISI Type 420 stainless steels was studied. The AISI Type 420 stainless steels specimens were heat treated at the temperature of 1050°C for 1 hour to reach austenite stabilization and then quench in the oil. After that, the specimens were tempered at the temperature of 150, 250, 350 and 450°C for 30 minutes and then air cooled to the room temperature. The electrochemical potentiodynamic polarization test was conducted at 3.5% sodium chloride solution to evaluate corrosion rate and pitting corrosion behaviour. The Scanning Electron Microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) were used to evaluate the pitting corrosion product. The result have shown that highest pitting potential was found in the sample tempered at 250°C and corrosion pits were found to initiate preferentially around chromium carbides.

  8. Failure Mechanism of a Stellite Coating on Heat-Resistant Steel

    Science.gov (United States)

    Wang, Dong; Zhao, Haixing; Wang, Huang; Li, Yuyan; Liu, Xia; He, Guo

    2017-09-01

    The Stellite 21 coating on the heat-resistant steel X12CrMoWVNbN10-1-1 (so-called COSTE) used in a steam turbine valve was found to be fatigue broken after service at around 873 K (600 °C) for about 8 years. In order to investigate the failure mechanism, a fresh Stellite 21 coating was also prepared on the same COSTE steel substrate by using the similar deposition parameters for comparison. It was found that the Stellite 21 coating was significantly diluted by the steel, resulting in a thin Fe-rich layer in the coating close to the fusion line. Such high Fe concentration together with the incessant Fe diffusion from the steel substrate to the coating during the service condition (about 873 K (600 °C) for long time) induced the eutectoid decomposition of the fcc α-Co(Fe,Cr,Mo) solid solution, forming an irregular eutectoid microstructure that was composed of the primitive cubic α'-FeCo(Cr,Mo) phase and the tetragonal σ-CrCo(Fe,Mo) phase. The brittle nature of such α'/ σ eutectoid microstructure contributed to the fatigue fracture of the Stellite 21 coating, resulting in an intergranular rupture mode.

  9. Corrosive-wear resistance of stainless steels for the impeller of slurry pump used in zinc hydrometallurgy process

    Directory of Open Access Journals (Sweden)

    Ping LI

    2005-08-01

    Full Text Available This paper presents corrosive-wear (C-W behaviors of three kinds of steels under the simulating condition of traditional zinc hydrometallurgy process by using a self-made rotating disk apparatus. Result shows that pure wear loss rate is significantly larger than pure corrosion loss rate. Under this C-W condition, the ranking of C-W resistance is S2 > S3 > S1 (S1: austenite stainless steel; S2: CD-4MCu duplex stainless steel; S3 :17-4PH stainless steel. S2 has excellent C-W resistance due to strong surface deformation strengthening effect of high-density dislocations of the γ phase. S3 also has excellent C-W resistance owing to high hardness and strength. However, S1 does not show good C-W resistance under strong erosion of liquid-solid slurry because of its single-phase austenitic structure and very low hardness. As a result, duplex stainless steels as well as 17-4 PH stainless steel can be used as impeller candidate materials in the zinc hydrometallurgy process due to their excellent C-W resistance and lower cost.

  10. 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.

  11. Effects of Rare Earth Metal Addition on Wear Resistance of Chromium-Molybdenum Cast Steel

    Directory of Open Access Journals (Sweden)

    Kasinska J.

    2017-09-01

    Full Text Available This paper discusses changes in the microstructure and abrasive wear resistance of G17CrMo5-5 cast steel modified with rare earth metals (REM. The changes were assessed using scanning microscopy. The wear response was determined in the Miller test to ASTM G75. Abrasion tests were supplemented with the surface profile measurements of non-modified and modified cast steel using a Talysurf CCI optical profilometer. It was demonstrated that the modification substantially affected the microstructure of the alloy, leading to grain size reduction and changed morphology of non-metallic inclusions. The observed changes in the microstructure resulted in a three times higher impact strength (from 33 to 99 kJ/cm2 and more than two times higher resistance to cracking (from 116 to 250 MPa. The following surface parameters were computed: Sa: Arithmetic mean deviation of the surface, Sq: Root-mean-square deviation of the surface, Sp: Maximum height of the peak Sv: Maximum depth of the valley, Sz: Ten Point Average, Ssk: Asymmetry of the surface, Sku: Kurtosis of the surface. The findings also indicated that the addition of rare earth metals had a positive effect on the abrasion behaviour of G17CrMo5-5 cast steel.

  12. Evaluation of the stress corrosion cracking resistance of several high strength low alloy steels

    Science.gov (United States)

    Humphries, T. S.; Nelson, E. E.

    1980-01-01

    The stress corrosion cracking resistance was studied for high strength alloy steels 4130, 4340, for H-11 at selected strength levels, and for D6AC and HY140 at a single strength. Round tensile and C-ring type specimens were stressed up to 100 percent of their yield strengths and exposed to alternate immersion in salt water, salt spray, the atmosphere at Marshall Space Flight Center, and the seacoast at Kennedy Space Center. Under the test conditions, 4130 and 4340 steels heat treated to a tensile strength of 1240 MPa (180 ksi), H-11 and D6AC heat treated to a tensile strength of 1450 MPa (210 ksi), and HY140 (1020 MPa, 148 ksi) are resistant to stress corrosion cracking because failures were not encountered at stress levels up to 75 percent of their yield strengths. A maximum exposure period of one month for alternate immersion in salt water or salt spray and three months for seacoast is indicated for alloy steel to avoid false indications of stress corrosion cracking because of failure resulting from severe pitting.

  13. Development of Press Hardening Steel with High Resistance to Hydrogen Embrittlement

    Science.gov (United States)

    Bian, Jian; Mohrbacher, Hardy; Lu, Hongzhou; Wang, Wenjun

    Press hardening has become the state-of-art technology in the car body manufacturing to enhance safety standard and to reduce CO2 emission of new vehicles. However the delayed cracking due to hydrogen embrittlement remains to be a critical issue. Generally press hardening steel is susceptible to hydrogen embrittlement due to ultra-high strength and martensitic microstructure. The hydrogen charging tests clearly demonstrate that only a few ppm of diffusible hydrogen is sufficient to cause such embrittlement. Currently the hydrogen embrittlement cannot be detected in the press hardened components and the embitteled components could collapse in the crash situation with fatal consequences arisen through dramatic loss in both strength and ductility. This paper introduces a new metallurgical solution to increase the resistance to hydrogen embrittlement of conventional press hardening steel based on 22MnB5 by Nb microalloying. In the hydrogen embrittlement and permeation tests the impact of Nb microalloying on the hydrogen embrittlement behavior was investigated under different hydrogen charging conditions and constant load. The test results revealed that Nb addition increases the resistance to hydrogen embrittlement due to reduced hydrogen diffusivity. The focus of this paper is to investigate the precipitation behavior of microalloying elements by using TEM and STEM and to find out the mechanisms leading to higher performance against hydrogen embrittlement of Nb alloyed steels.

  14. Structural Component Fabrication and Characterization of Advanced Radiation Resistant ODS Steel for Next Generation Nuclear Systems

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sang Hoon; Kim, Young Chun; Jin, Hyun Ju; Choi, Byoung Kwon; Kang, Suk Hoon; Kim, Tae Kyu [KAERI, Daejeon (Korea, Republic of)

    2016-05-15

    In a sodium-cooled fast reactor (SFR), the coolant outlet temperature and peak temperature of the fuel cladding tube will be about 545 .deg. C and 700 .deg. C with 250 dpa of a very high neutron dose rate. To realize this system, it is necessary to develop an advanced structural material having high creep and irradiation resistance at high temperatures. Austenitic stainless steel may be one of the candidates because of good strength and corrosion resistance at the high temperatures, however irradiation swelling severely occurred to 120dpa at high temperatures and this eventually leads to a decrease of the mechanical properties and dimensional stability. Advanced radiation resistant ODS steel (ARROS) has been newly developed for the in-core structural components in SFR, which has very attractive microstructures to achieve both superior creep and radiation resistances at high temperatures [4]. Nevertheless, the use of ARROS as a structural material essentially requires the fabrication technology development for component parts such as sheet, plate and tube. In this study, plates and tubes were tentatively fabricated with a newly developed alloy, ARROS. Microstructures as well as mechanical properties were also investigated to determine the optimized condition of the fabrication processes.

  15. Microstructure and mechanical properties of dual phase steels, with different martensite morphology, produced during TLP bonding of a low C-Mn steel

    Science.gov (United States)

    Fazaeli, Abolfazl; Ekrami, Aliakbar; Kokabi, Amir Hossein

    2016-09-01

    In this research, production of ferrite - martensite dual phase Steels with different martensite morphology was considered during transient liquid phase bonding of a low carbon steel. The steel was bonded using an iron base interlayer with melting point of 1443 K and 40 μm thickness. Bonding process carried out at 1473 K, under pressure of 0.5 MPa, at different holding time of 10, 20, 30 and 40 minutes. Microstructural studies of joint region showed that isothermal solidification completed at the bonding time of 40 minutes. Microstructure of joints made at the bonding time of 10, 20, and 30 minutes consists of two distinct region, athermal and isothermal solidified zones. Microstructure of these zones was studied and chemical composition of these zones was determined by EDS. Joints made with bonding time of 40 minutes were homogenized at 1008 K and then cooled into cold water to produce dual phase ferrite and martensite microstructure with different martensite morphology. According to shear test results, it was found that the shear strength of ferrite - fibrous martensite microstructure is greater than those with ferrite - continuous martensite and ferrite - blocky martensite microstructure.

  16. Development of stress corrosion cracking resistant welds of 321 stainless steel by simple surface engineering

    Science.gov (United States)

    Mankari, Kamal; Acharyya, Swati Ghosh

    2017-12-01

    We hereby report a simple surface engineering technique to make AISI grade 321 stainless steel (SS) welds resistant to stress corrosion cracking (SCC) in chloride environment. Heat exchanger tubes of AISI 321 SS, welded either by (a) laser beam welding (LBW) or by (b) metal inert gas welding (MIG) were used for the study. The welds had high magnitude of tensile residual stresses and had undergone SCC in chloride environment while in service. The welds were characterized using field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). Subsequently, the welded surfaces were subjected to buffing operation followed by determination of residual stress distribution and surface roughness by XRD and surface profilometer measurements respectively. The susceptibility of the welds to SCC was tested in buffed and un-buffed condition as per ASTM G-36 in boiling MgCl2 for 5 h and 10 h, followed by microstructural characterization by using optical microscope and FESEM. The results showed that the buffed surfaces (both welds and base material) were resistant to SCC even after 10 h of exposure to boiling MgCl2 whereas the un-buffed surfaces underwent severe SCC for the same exposure time. Buffing imparted high magnitude of compressive stresses on the surface of stainless steel together with reduction in its surface roughness and reduction in plastic strain on the surface which made the welded surface, resistant to chloride assisted SCC. Buffing being a very simple, portable and economic technique can be easily adapted by the designers as the last step of component fabrication to make 321 stainless steel welds resistant to chloride assisted SCC.

  17. Microstructure and Hardness Distribution of Resistance Welded Advanced High Strength Steels

    DEFF Research Database (Denmark)

    Pedersen, Kim Richardt; Harthøj, Anders; Friis, Kasper Leth

    2008-01-01

    In this work a low carbon steel and two high strength steels (DP600 and TRIP700) have been resistance lap welded and the hardness profiles were measured by micro hardness indentation of cross sections of the joint. The resulting microstructure of the weld zone of the DP-DP and TRIP-TRIP joints were...... found to consist of a martensitic structure with a significant increase in hardness. Joints of dissimilar materials mixed completely in the melted region forming a new alloy with a hardness profile lying in between the hardness measured in joints of the similar materials. Furthermore the joints were...... simulated numerically and together with the material carbon equivalent, austenization temperatures and the thermal history the simulations were used to estimate the resulting post weld hardness using the commercial FE code SORPAS. The hardness of the welds of dissimilar materials was estimated...

  18. Experimental research results of solid particle erosion resistance of blade steel with protective coating

    Science.gov (United States)

    Kachalin, G. V.; Mednikov, A. F.; Tkhabisimov, A. B.; Seleznev, L. I.

    2017-11-01

    The paper presents the results of metallographic studies and solid particle erosion tests of uncoated blade steel 20kH13 samples and samples with a protective coating based on chromium carbide (Cr-CrC) at a flow (air) velocity CA = 180 m/s, flow temperature tA = 25 °C, attack angle α = 30° and consumption of solid abrasive particles GP = 5·10-4 kg/s. It was found that the coating has a granular structure, a thickness is about 11 μm, the microhardness of the surface is 1520 ± 50 HV0.05. Processing of the obtained data by statistical analysis methods showed that the protective coating based on Cr-CrC increases the solid particle erosion resistance of the blade steel 20kH13 by the incubation-transitional period duration more than 2.5 times.

  19. Liquid Inclusions in Heat-Resistant Steel Containing Rare Earth Elements

    Science.gov (United States)

    Li, Yandong; Liu, Chengjun; Zhang, Tongsheng; Jiang, Maofa; Peng, Cheng

    2017-04-01

    Abundant thermodynamic data of pure substances were incorporated in the coupled thermodynamic model of inclusion precipitation and solute micro-segregation during the solidification of heat-resistant steel containing rare earth elements. The liquid inclusions Ce2 x Al2 y Si1- x-y O z (0 method for generation Gibbs free energy of liquid inclusions in molten steel was given. The accuracy of accomplished model was validated through plant trials, lab-scale experiments, and the data published in the literature. The comparisons of results calculated by FactSage with the model were also discussed. Finally, the stable area of liquid inclusions was predicted and the liquid inclusions with larger size were found in the preliminary experiments.

  20. High performance corrosion and wear resistant composite titanium nitride layers produced on the AZ91D magnesium alloy by a hybrid method

    Directory of Open Access Journals (Sweden)

    Michał Tacikowski

    2014-09-01

    Full Text Available Composite, diffusive titanium nitride layers formed on a titanium and aluminum sub-layer were produced on the AZ91D magnesium alloy. The layers were obtained using a hybrid method which combined the PVD processes with the final sealing by a hydrothermal treatment. The microstructure, resistance to corrosion, mechanical damage, and frictional wear of the layers were examined. The properties of the AZ91D alloy covered with these layers were compared with those of the untreated alloy and of some engineering materials such as 316L stainless steel, 100Cr6 bearing steel, and the AZ91D alloy subjected to commercial anodizing. It has been found that the composite diffusive nitride layer produced on the AZ91D alloy and then sealed by the hydrothermal treatment ensures the corrosion resistance comparable with that of 316L stainless steel. The layers are characterized by higher electrochemical durability which is due to the surface being overbuilt with the titanium oxides formed, as shown by the XPS examinations, from titanium nitride during the hydrothermal treatment. The composite titanium nitride layers exhibit high resistance to mechanical damage and wear, including frictional wear which is comparable with that of 100Cr6 bearing steel. The performance properties of the AZ91D magnesium alloy covered with the composite titanium nitride coating are substantially superior to those of the alloy subjected to commercial anodizing which is the dominant technique employed in industrial practice.

  1. Improved Corrosion and Abrasion Resistance of Organic-Inorganic Composite Coated Electro-galvanized Steels for Digital TV Panels

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Du-Hwan; Noh, Sang-Geol; Park, Jong-Tae; Kang, Choon-Ho [POSCO Technical Research Laboratories, Pohang (Korea, Republic of)

    2015-10-15

    Recently, household electronic industries require environmentally-friendly and highly functional steels in order to enhance the quality of human life. Customers especially require both excellent corrosion and abrasion resistant anti-fingerprint steels for digital TV panels. Thus POSCO has developed new functional electro-galvanized steels, which have double coated layers with organic-inorganic composites on the zinc surface of the steel for usage as the bottom chassis panel of TVs. The inorganic solution for the bottom layer consists of inorganic phosphate, magnesium, and zirconium compounds with a small amount of epoxy binder, and affords both improved adhesion properties by chemical conversion reactions and corrosion resistance due to a self-healing effect. The composite solution for the top layer was prepared by fine dispersion of organic-inorganic ingredients that consist of a urethane modified polyacrylate polymer, hardener, silica sol and a titanium complex inhibitor in aqueous media. Both composite solutions were coated on the steel surface by using a roll coater and then cured through an induction furnace in the electro-galvanizing line. New anti-fingerprint steel was evaluated for quality performance through such procedures as the salt spray test for corrosion resistance, tribological test for abrasion resistance, and conductivity test for surface electric conductance regarding to both types of polymer resin and coating weight of composite solution. New composite coated anti-fingerprint steels afford both better corrosion resistance and abrasion properties compared to conventional anti-fingerprint steel that mainly consists of acrylate polymers. Detailed discussions of both composite solutions and experimental results suggest that urethane modifications of acrylate polymers of composite solutions play a key role in enhanced quality performances.

  2. 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.

  3. 78 FR 55241 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Preliminary Results of...

    Science.gov (United States)

    2013-09-10

    ... International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...) is conducting an administrative review of the countervailing duty (CVD) order on corrosion-resistant.... SUPPLEMENTARY INFORMATION: Scope of the Order The merchandise covered by this Order \\2\\ is certain corrosion...

  4. 77 FR 16810 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2012-03-22

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on corrosion-resistant...

  5. 76 FR 20954 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2011-04-14

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on corrosion-resistant...

  6. 75 FR 18153 - Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2010-04-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products from the Republic of Korea..., the Department published in the Federal Register the countervailing duty order on corrosion-resistant...

  7. Acoustic emission analysis of crack resistance and fracture behavior of 20GL steel having the gradient microstructure and strength

    Science.gov (United States)

    Nikulin, S.; Nikitin, A.; Belov, V.; Rozhnov, A.; Turilina, V.; Anikeenko, V.; Khatkevich, V.

    2017-07-01

    The crack resistances as well as fracture behavior of 20GL steel quenched with a fast-moving water stream and having gradient microstructure and strength are analyzed. Crack resistance tests with quenched and normalized flat rectangular specimens having different cut lengths loaded by three-point bending with acoustic emission measurements have been performed. The critical J-integral has been used as the crack resistance parameter of the material. Quenching with a fast moving water stream leads to gradient (along a specimen wall thickness) strengthening of steel due to highly refined gradient microstructure formation of the troostomartensite type. Quenching with a fast-moving water stream increases crack resistance Jc , of 20GL steel by a factor of ∼ 1.5. The fracture accrues gradually with the load in the normalized specimens while the initiated crack is hindered in the variable ductility layer and further arrested in the more ductile core in the quenched specimens.

  8. The Effect of Two Amine-Based Corrosion Inhibitors in Improving the Corrosion Resistance of Carbon Steel in Sea Water

    Science.gov (United States)

    Rihan, Rihan; Shawabkeh, Reyad; Al-Bakr, Nawaf

    2014-03-01

    This study investigates the effect of two amine-based corrosion inhibitors in reducing the corrosion rate (CR) of 1018 carbon steel in formulated sea water. For discussion purposes, the two inhibitors are named Inhibitor A (belongs to the alkyl pyridine benzyl chloride quaternary family of inhibitors) and Inhibitor B (belongs to the alkyl amines family of inhibitors). The two inhibitors are routinely considered for applications by Saudi Aramco, the world's largest oil producing and processing company, for reducing its corrosion problems in carbon steel pipelines carrying oil and gas. The experimental apparatus was a circulating flow loop system inside an autoclave. The experimental work was performed at pH 8.2, 55 °C, and 1000 rpm. The inhibitors were evaluated at three different concentrations of 5, 10, and 15 ppm. The CR was determined using the weight loss method and electrochemical methods such potentiodynamic sweep and linear polarization resistance. The experimental results indicate that Inhibitor B reduced the CR more than that of Inhibitor A.

  9. Effect of thermal ageing on the corrosion resistance of stainless steel type 316L exposed in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Y.; Kish, J., E-mail: jiaoyn@mcmaster.ca, E-mail: kishjr@mcmaster.ca [McMaster University, Hamilton, ON (Canada); Zheng, W., E-mail: wenyue.zheng@nrcan.rncan.gc.ca [Canmet Materials, Hamilton, ON (Canada); Guzonas, D. [Atomic Energy of Canada Limited, Chalk River, ON (Canada); Cook, W., E-mail: wcook@unb.ca [University of New Brunswick, Fredericton, NB (Canada)

    2014-07-01

    The tendency for intermetallic precipitates to form in austenitic stainless steel during prolonged exposure at the expected operating temperature of the fuel cladding in the Canadian supercritical water reactor (SCWR) concept represents a possible serious threat to the intrinsic in-service corrosion performance of the candidate alloy. The objective of this study was to better understand the extent to which a thermally-aged microstructure affects the mode and extent of corrosion exhibited by Type 316L stainless steel exposed in 25 MPa supercritical water (SCW) at 550 {sup o}C for 500 h. Mechanically-abraded samples were exposed in an as-received and thermally-aged condition. Thermal ageing conducted at 815 {sup o}C (peak fuel cladding temperature expected) for 1000 h was found to produce a discontinuous network of the carbide (M{sub 23}C{sub 6}), chi (χ), laves (η) and sigma (σ) phases. The similar weight gain and oxide scale structure, composition and thickness suggested that the thermally-aged condition does not have a marked influence on the corrosion resistance. (author)

  10. Development and Study of Hard-Facing Materials on the Base of Heat-Resisting High-Hardness Steels for Plasma-Jet Hard- Facing in Shielding-Doping Nitrogen Atmosphere

    Science.gov (United States)

    Malushin, N. N.; Kovalev, A. P.; Valuev, D. V.; Shats, E. A.; Borovikov, I. F.

    2016-08-01

    The authors develop hard-facing materials on the base of heat-resisting highhardness steels for plasma-jet hard-facing in nitrogen atmosphere for manufacturing parts of mining and metallurgic equipment which significantly simplify the production process and effect a saving when producing bimetallic parts and tools.

  11. High corrosion resistance of austenitic stainless steel alloyed with nitrogen in an acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Metikos-Hukovic, M., E-mail: mmetik@fkit.h [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Babic, R. [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Grubac, Z. [Department of General and Inorganic Chemistry, Faculty of Chemistry and Technology, University of Split, 21000 Split (Croatia); Petrovic, Z. [Department of Electrochemistry, Faculty of Chemical Engineering and Technology, University of Zagreb, Savska 16, P.O. Box 177, 100000 Zagreb (Croatia); Lajci, N. [Faculty of Mine and Metallurgy, University of Prishtina, 10000 Prishtina, Kosovo (Country Unknown)

    2011-06-15

    Highlights: {yields} ASS alloyed with nitrogen treated at 1150 {sup o}C exhibits microstructure homogeneity. {yields} Passivation peak of ASS corresponds to oxidation of metal and absorbed hydrogen. {yields} Transfer phenomena and conductivity depend on the film formation potential. {yields} Electronic structure of the passive film and its corrosion resistance correlate well. {yields} Passive film on ASS with nitrogen is low disordered and high corrosion resistant. - Abstract: Passivity of austenitic stainless steel containing nitrogen (ASS N25) was investigated in comparison with AISI 316L in deareated acid solution, pH 0.4. A peculiar nature of the passivation peak in a potentiodynamic curve and the kinetic parameters of formation and growth of the oxide film have been discussed. The electronic-semiconducting properties of the passive films have been correlated with their corrosion resistance. Alloying austenitic stainless steel with nitrogen increases its microstructure homogeneity and decreases the concentration of charge carriers, which beneficially affects the protecting and electronic properties of the passive oxide film.

  12. Evaluation of seismic reliability of steel moment resisting frames rehabilitated by concentric braces with probabilistic models

    Directory of Open Access Journals (Sweden)

    Fateme Rezaei

    2017-08-01

    Full Text Available Probability of structure failure which has been designed by "deterministic methods" can be more than the one which has been designed in similar situation using probabilistic methods and models considering "uncertainties". The main purpose of this research was to evaluate the seismic reliability of steel moment resisting frames rehabilitated with concentric braces by probabilistic models. To do so, three-story and nine-story steel moment resisting frames were designed based on resistant criteria of Iranian code and then they were rehabilitated based on controlling drift limitations by concentric braces. Probability of frames failure was evaluated by probabilistic models of magnitude, location of earthquake, ground shaking intensity in the area of the structure, probabilistic model of building response (based on maximum lateral roof displacement and probabilistic methods. These frames were analyzed under subcrustal source by sampling probabilistic method "Risk Tools" (RT. Comparing the exceedance probability of building response curves (or selected points on it of the three-story and nine-story model frames (before and after rehabilitation, seismic response of rehabilitated frames, was reduced and their reliability was improved. Also the main effective variables in reducing the probability of frames failure were determined using sensitivity analysis by FORM probabilistic method. The most effective variables reducing the probability of frames failure are  in the magnitude model, ground shaking intensity model error and magnitude model error

  13. High strength and heat resistant chromium steels for sodium-cooled fast reactors.

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, S.; Grandy, C.; Farmer, M.; Brunsvold, A.

    2004-12-22

    This report provides the results of a preliminary phase of a project supporting the Advanced Nuclear Fuel Cycle Technology Initiative at ANL. The project targets the Generation IV nuclear energy systems, particularly the area of reducing the cost of sodium-cooled fast-reactors by utilizing innovative materials. The main goal of the project is to provide the nuclear heat exchanger designers a simplified means to quantify the cost advantages of the recently developed high strength and heat resistant ferritic steels with 9 to 13% chromium content. The emphasis in the preliminary phase is on two steels that show distinctive advantages and have been proposed as candidate materials for heat exchangers and also for reactor vessels and near-core components of Gen IV reactors. These steels are the 12Cr-2W (HCM12A) and 9Cr-1MoVNb (modified 9Cr-1Mo). When these steels are in tube form, they are referred to in ASTM Standards as T122 and T91, respectively. A simple thermal-hydraulics analytical model of a counter-flow, shell-and-tube, once-through type superheated steam generator is developed to determine the required tube length and tube wall temperature profile. The single-tube model calculations are then extended to cover the following design criteria: (i) ratio of the tube stress due to water/steam pressure to the ASME B&PV Code allowable stress, (ii) ratio of the strain due to through-tube-wall temperature differences to the material fatigue limit, (iii) overall differential thermal expansion between the tube and shell, and (iv) total amount of tube material required for the specified heat exchanger thermal power. Calculations were done for a 292 MW steam generator design with 2200 tubes and a steam exit condition of 457 C and 16 MPa. The calculations were performed with the tubes made of the two advanced ferritic steels, 12Cr-2W and 9Cr-1MoVNb, and of the most commonly used steel, 2 1/4Cr-1Mo. Compared to the 2 1/4Cr-1Mo results, the 12Cr-2W tubes required 29% less

  14. Evaluation of erosion-corrosion resistance in Fe-Mn-Al austenitic steels

    OpenAIRE

    William Arnulfo Aperador; Jorge Hernando Bautista Ruiz; Betancurt,Juan D.

    2013-01-01

    In this paper, the effects of Mn and Al against corrosion/errosion resistance of three samples of the Fe-Mn-Al austenitic alloys are evaluated. The samples have composition Fe-(4,9 ~ 11,0 wt. (%)) Al-(17,49 ~ 34,3 wt. (%)) Mn-(0,43 ~ 1,25 wt. (%))C, those were prepared in an induction furnace from high purity materials. The alloys were evaluated in a composed solution of NaCl 0,5 M and Silica in a special chamber and AISI 316 stainless steel as reference material. The electrochemical characte...

  15. Effect of niobium on corrosion resistance to sulfuric acid of 430 ferritic stainless steel

    OpenAIRE

    Neusa Alonso-Falleiros; Stephan Wolynec

    1998-01-01

    The influence of niobium on corrosion resistance to 0.5M H2SO4 of 17% Cr ferritic stainless steels, to which it was added in amounts larger than that necessary to stabilize the interstitial elements, was investigated. Their performance was compared to that of other two Fe-17%Cr alloys, one without additions and another containing 0.93% molybdenum. Through weight and electrochemical measurements and through morphologic examination of corroded surface it was found that the corrosion of these al...

  16. Interstitial Hardening of Stainless Steel for Enhanced Corrosion Resistance for Naval Applications

    Science.gov (United States)

    2017-03-01

    process, the nitrogen activity in the gas atmosphere, a(N2), was fixed at 7400, the nitriding time was fixed at 20 h, and an in situ gaseous HCI pre...that notwithstanding any other provision of law , no person shall be subject to any penalty for failing to comply with a collection of information if...Steel for Enhanced Corrosion Resistance for Naval Applications . 5b. GRANT NUMBER N00014-13-1-0691 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d

  17. Effects of heat treatment on properties of multi-element low alloy wear-resistant steel

    Directory of Open Access Journals (Sweden)

    SONG Xu-ding

    2007-02-01

    Full Text Available The paper has studied the mechanical properties and heat treatment effects on multi-element low alloy wear-resistant steel (MLAWS used as a material for the liner of rolling mill torii. The results show that when quenched at 900-920℃ and tempered at 350-370℃, the MLAWS has achieved hardness above 60 HRC, tensile strength greater than 1 600 MPa, impact toughness higher than 18J/cm2 and fracture toughness greater than 37 MPa

  18. Study on creep behavior of Grade 91 heat-resistant steel using theta projection method

    Science.gov (United States)

    Ren, Facai; Tang, Xiaoying

    2017-10-01

    Creep behavior of Grade 91 heat-resistant steel used for steam cooler was characterized using the theta projection method. Creep tests were conducted at the temperature of 923K under the stress ranging from 100-150MPa. Based on the creep curve results, four theta parameters were established using a nonlinear least square fitting method. Four theta parameters showed a good linearity as a function of stress. The predicted curves coincided well with the experimental data and creep curves were also modeled to the low stress level of 60MPa.

  19. Precipitation behavior in a nitride-strengthened martensitic heat resistant steel during hot deformation

    Directory of Open Access Journals (Sweden)

    Wenfeng Zhang

    2015-09-01

    Full Text Available The stress relaxation curves for three different hot deformation processes in the temperature range of 750–1000 °C were studied to develop an understanding of the precipitation behavior in a nitride-strengthened martensitic heat resistant steel (Zhang et al., Mater. Sci. Eng. A, 2015 [1]. This data article provides supporting data and detailed information on how to accurately analysis the stress relaxation data. The statistical analysis of the stress peak curves, including the number of peaks, the intensity of the peaks and the integral value of the pumps, was carried out. Meanwhile, the XRD energy spectrum data was also calculated in terms of lattice distortion.

  20. Precipitation behavior in a nitride-strengthened martensitic heat resistant steel during hot deformation.

    Science.gov (United States)

    Zhang, Wenfeng; Su, Qingyong; Xu, Mi; Yan, Wei

    2015-09-01

    The stress relaxation curves for three different hot deformation processes in the temperature range of 750-1000 °C were studied to develop an understanding of the precipitation behavior in a nitride-strengthened martensitic heat resistant steel (Zhang et al., Mater. Sci. Eng. A, 2015) [1]. This data article provides supporting data and detailed information on how to accurately analysis the stress relaxation data. The statistical analysis of the stress peak curves, including the number of peaks, the intensity of the peaks and the integral value of the pumps, was carried out. Meanwhile, the XRD energy spectrum data was also calculated in terms of lattice distortion.

  1. New electrodes for welding cold-resistant steels in designs of ships and floating drilling platforms

    Energy Technology Data Exchange (ETDEWEB)

    Artemyev, A.Ya.; Grishchenko, L.V.; Petrykin, V.I.

    1983-01-01

    Electrodes are developed of brands 48N-OZS-1 and 48N-30 designed for welding new cold-resistant Z-steels of brands 10GNB-Sh, 10KhNDMF-SH, AV-1Sh and AB-2Sh. The possibility is shown of the use of these electrodes for welding the designs of ships and floating drilling platforms operating under arctic conditions with temperatures to minus 60/sup 0/C. The introduction of new electrodes provides a saving of about R 4,000 for each introduced ton.

  2. Effect of Carbonitriding on Corrosion Resistance of Steel 30MnB5 in Two Acidic Environments

    Science.gov (United States)

    Yazici, Aysel; Sadrettin Zeybek, M.; Güler, Hüseyin; Koç, Muhterem; Göksel Pekýtkan, F.

    2017-07-01

    Corrosion resistance of steel 30MnB5 is studied after carbonitriding, after conventional quenching, and without treatment. Corrosion tests are performed for from 24 to 168 h in two acidic environments (in a hydrochloric acid solution with 10% mole fraction and in fertilizer-containing soil). It is shown that the rate of corrosion of the steel in both environments after carbonitriding is lower than after quenching).

  3. Study on impact properties of creep-resistant steel thermally simulated heat affected zone

    Directory of Open Access Journals (Sweden)

    Mitrović Radivoje M.

    2012-01-01

    Full Text Available The steam pipe line (SPL and steam line material, along with its welded joints, subject to damage that accumulates during operation in coal power plants. As a result of thermal fatigue, dilatation of SPL at an operating temperature may lead to cracks initiation at the critical zones within heat affected zone (HAZ of steam pipe line welded joints. By registration of thermal cycle during welding and subsequent HAZ simulation is possible to obtain target microstructure. For the simulation is chosen heat resisting steel, 12H1MF (designation 13CrMo44 according to DIN standard. From the viewpoint of mechanical properties, special attention is on impact toughness mostly because very small number of available references. After simulation of single run and multi run welding test on instrumented Charpy pendulum. Metallographic and fractographic analysis is also performed, on simulated 12H1MF steel from service and new, unused steel. The results and correlation between microstructure and impact toughness is discussed, too.

  4. A Finite Element Analysis of Bearing Resistance of Timber Loaded through a Steel Plate

    Directory of Open Access Journals (Sweden)

    Leijten A.J.M.

    2012-01-01

    Full Text Available Decrease projected length of bolts due to bending deformation in timber joints compresses the steel washers onto timber member and increases lateral resistance of the joints. As this lateral strength increase primarily depend on bearing characteristics of timber beneath the steel washers, a finite element analysis was performed to predict their bearing-embedment behavior. A 3-D finite element model consisting of 8-node solid and contact pair elements was developed using ANSYS assuming an anisotropic plasticity model for timber and an elastic-perfectly plastic model for the washers. Material constants for both steel washer and timber member were obtained from previous test data. The results of the analysis were in good agreement with the experimental load-embedment curves as well as the analytical curves obtained in a previous study based on a rigid-body-spring-model. The same approach was also used to evaluate the effective bearing length (under uniform compression of a 50 mm depth timber block partially compressed.

  5. Microstructure and Tensile-Shear Properties of Resistance Spot-Welded Medium Mn Steel

    Directory of Open Access Journals (Sweden)

    Qiang Jia

    2018-01-01

    Full Text Available The medium Mn steels are gaining increasing attention due to their excellent combination of mechanical properties and material cost. A cold-rolled 0.1C5Mn medium Mn steel with a ferrite matrix plus metastable austenite duplex microstructure was resistance spot-welded with various welding currents and times. The nugget size rose with the increase of heat input, but when the welding current exceeded the critical value, the tensile-shear load increased slowly and became unstable due to metal expulsion. The fusion zone exhibited a lath martensite microstructure, and the heat-affected zone was composed of a ferrite/martensite matrix with retained austenite. The volume fraction of retained austenite decreased gradually from the base metal to the fusion zone, while the microhardness presented a reverse varying trend. Interfacial failure occurred along the interface of the steel sheets with lower loading capacity. Sufficient heat input along with serious expulsion brought about high stress concentration around the weld nugget, and the joint failed in partial interfacial mode. Pull-out failure was absent in this study.

  6. Laws of alloyed cementite particles nucleation during heat-resistant steels carburizing

    Directory of Open Access Journals (Sweden)

    M. Yu. Semenov

    2014-01-01

    Full Text Available The article considers a problem analyzing a nucleation of cementite type carbides in carburized heat-resistant steels for the turbofan engines gear wheels.The verification of previously hypothesized mechanism of dislocation nucleation particles chromium-alloyed cementite during process of carburizing was accepted as an objective of the work.As a methodological basis of this paper were accepted the numerical experiments based on the kinetic theory of nucleation, as well as on the known results of experimental studies.According to the kinetic theory of nucleation, a new phase in the solid solutions take place in the defects of the crystal structure of the metal such as inter-grain boundaries and dislocations clusters. A principle feature of the inter-grain boundary mechanism of nucleation is formation of carbide lattice. It is of great practical interest because the cementite lattice drops mechanical properties of hardened parts.According to the experimental studies, the average chromium concentration in the alloyed cementite twice exceeds its Cr content in the heat-resistant steels. Furthermore, the areas of abnormally high (more than ten times in comparison with the average content chromium concentration in cementite have been experimentally revealed.Numerical experiments have revealed that the nucleation of cementite particles alloyed with chromium (chromium concentration of 3% or more occurs, mainly, by the dislocation mechanism on the concentration fluctuations of the alloying element. According to calculations, an obligatory prerequisite to start an active nucleation process of new phase in the solid solution is a local increase of the chromium concentration up to 40%.Despite the lack of physical prerequisites for the formation of chromium precipitates, this phenomenon is explained by a strong chemical affinity of chromium and carbon, causing diffusion of chromium atoms in the region of the carbon atoms clusters. The formation of carbon

  7. Pitting corrosion resistance of a novel duplex alloy steel in alkali-activated slag extract in the presence of chloride ions

    Science.gov (United States)

    Shi, Jin-jie; Ming, Jing; Liu, Xin

    2017-10-01

    In this study, two types of reinforcing steels (conventional low-carbon steel and a novel duplex alloy steel with Cr and Mo) were exposed to chloride-contaminated extract solutions (ordinary Portland cement (OPC) extract and alkali-activated slag (AAS) extract) to investigate their pitting corrosion resistance. The results confirm that the pitting corrosion resistance of the alloy steel is much higher than that of the low-carbon steel in both extract solutions with various NaCl concentrations. Moreover, for each type of steel, the AAS extract contributes to a higher pitting corrosion resistance compared with the OPC extract in the presence of chloride ions, likely because of the formation of flocculent precipitates on the steel surface.

  8. Effect of Mn Content and Solution Annealing Temperature on the Corrosion Resistance of Stainless Steel Alloys

    Directory of Open Access Journals (Sweden)

    Ihsan-ul-Haq Toor

    2014-01-01

    Full Text Available The corrosion behavior of two specially designed austenitic stainless steels (SSs having different Nickel (Ni and Manganese (Mn contents was investigated. Prior to electrochemical tests, SS alloys were solution-annealed at two different temperatures, that is, at 1030°C for 2 h and 1050°C for 0.5 h. Potentiodynamic polarization (PD tests were carried out in chloride and acidic chloride, whereas linear polarization resistance (LPR and electrochemical impedance spectroscopy (EIS was performed in 0.5 M NaCl solution at room temperature. SEM/EDS investigations were carried out to study the microstructure and types of inclusions present in these alloys. Experimental results suggested that the alloy with highest Ni content and annealed at 1050°C/0.5 hr has the highest corrosion resistance.

  9. Corrosion Resistance of Galvanized Steel in the Environment of a Bioreactor

    Directory of Open Access Journals (Sweden)

    Šustr Michal

    2016-06-01

    Full Text Available The article deals with monitoring the corrosion resistibility of welded materials in the anaerobic fermenter (bioreactor. The main goal of this research is to assess the change of hardness after degradation. The change of hardness occurs in the corrosion environment and it correlates with the corrosion resistibility of material. The purpose of this experiment is to recognize the possibilities of using the CMT welded materials in the defined environment. As an innovative technology the acoustic emission method is used for assessment of surface layer disruption during hardness testing. Aluminium alloy with galvanized steel (AluZinc was used as an experimental material. The basic materials were welded by the filler material AlSi3.

  10. Enhanced corrosion resistance of strontium hydroxyapatite coating on electron beam treated surgical grade stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Gopi, D., E-mail: dhanaraj_gopi@yahoo.com [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, Tamilnadu (India); Rajeswari, D. [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Ramya, S. [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Sekar, M. [Department of Chemistry, Periyar University, Salem 636 011, Tamilnadu (India); Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); R, Pramod; Dwivedi, Jishnu [Industrial and Medical Accelerator Section, Raja Ramanna Centre for Advanced Technology, Indore 452 013, Madhya Pradesh (India); Kavitha, L., E-mail: louiskavitha@yahoo.co.in [Centre for Nanoscience and Nanotechnology, Periyar University, Salem 636 011, Tamilnadu (India); Department of Physics, Periyar University, Salem 636 011, Tamilnadu (India); Ramaseshan, R. [Thin film and Coatings Section, Surface and Nanoscience Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu (India)

    2013-12-01

    The surface of 316L stainless steel (316L SS) is irradiated by high energy low current DC electron beam (HELCDEB) with energy of 500 keV and beam current of 1.5 mA followed by the electrodeposition of strontium hydroxyapatite (Sr-HAp) to enhance its corrosion resistance in physiological fluid. The coatings were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and High resolution scanning electron microscopy (HRSEM). The Sr-HAp coating on HELCDEB treated 316L SS exhibits micro-flower structure. Electrochemical results show that the Sr-HAp coating on HELCDEB treated 316L SS possesses maximum corrosion resistance in Ringer's solution.

  11. Enhanced corrosion resistance of strontium hydroxyapatite coating on electron beam treated surgical grade stainless steel

    Science.gov (United States)

    Gopi, D.; Rajeswari, D.; Ramya, S.; Sekar, M.; R, Pramod; Dwivedi, Jishnu; Kavitha, L.; Ramaseshan, R.

    2013-12-01

    The surface of 316L stainless steel (316L SS) is irradiated by high energy low current DC electron beam (HELCDEB) with energy of 500 keV and beam current of 1.5 mA followed by the electrodeposition of strontium hydroxyapatite (Sr-HAp) to enhance its corrosion resistance in physiological fluid. The coatings were characterised by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and High resolution scanning electron microscopy (HRSEM). The Sr-HAp coating on HELCDEB treated 316L SS exhibits micro-flower structure. Electrochemical results show that the Sr-HAp coating on HELCDEB treated 316L SS possesses maximum corrosion resistance in Ringer's solution.

  12. Improvement of corrosion resistance of M50 bearing steel by implantation with metal ions

    Science.gov (United States)

    Nielsen, B. R.; Torp, B.; Rangel, C. M.; Simplicio, M. H.; Consiglieri, A. C.; DaSilva, M. F.; Paszti, F.; Soares, J. C.; Dodd, A.; Kinder, J.; Pitaval, M.; Thevenard, P.; Wing, R. G.

    1991-07-01

    With the overall objective to improve the service life and reliability of gas turbine engine bearings by increasing their corrosion resistance and rolling contact fatigue life a collaborative project under the EEC BRITE/EURAM programme has been initiated. The project is aimed at developing an ion implantation technique to implant bearing components with metallic species and to optimise the process particularly for applications where salt-water contamination of the lubricating oil might occur. Prior to implanting into bearing components, test specimens of M50 bearing steel implanted with Cr + and Ta + at several doses have been characterised by various techniques. This article reports on the implantation work, the RBS and NRA analysis for depth profiling and independent dose measurement, and the corrosion resistance measurements which have been performed in order to determine the optimum treatment.

  13. Nanotextured stainless steel for improved corrosion resistance and biological response in coronary stenting

    Science.gov (United States)

    Mohan, Chandini C.; Prabhath, Anupama; Cherian, Aleena Mary; Vadukumpully, Sajini; Nair, Shantikumar V.; Chennazhi, Krishnaprasad; Menon, Deepthy

    2014-12-01

    Nanosurface engineering of metallic substrates for improved cellular response is a persistent theme in biomaterials research. The need to improve the long term prognosis of commercially available stents has led us to adopt a `polymer-free' approach which is cost effective and industrially scalable. In this study, 316L stainless steel substrates were surface modified by hydrothermal treatment in alkaline pH, with and without the addition of a chromium precursor, to generate a well adherent uniform nanotopography. The modified surfaces showed improved hemocompatibility and augmented endothelialization, while hindering the proliferation of smooth muscle cells. Moreover, they also exhibited superior material properties like corrosion resistance, surface integrity and reduced metal ion leaching. The combination of improved corrosion resistance and selective vascular cell viability provided by nanomodification can be successfully utilized to offer a cell-friendly solution to the inherent limitations pertinent to bare metallic stents.

  14. Influence of Heat Treatment on Mercury Cavitation Resistance of Surface Hardened 316LN Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J [ORNL; Hsu, Julia [Massachusetts Institute of Technology (MIT)

    2010-11-01

    The cavitation-erosion resistance of carburized 316LN stainless steel was significantly degraded but not destroyed by heat treatment in the temperature range 500-800 C. The heat treatments caused rejection of some carbon from the carburized layer into an amorphous film that formed on each specimen surface. Further, the heat treatments encouraged carbide precipitation and reduced hardness within the carburized layer, but the overall change did not reduce surface hardness fully to the level of untreated material. Heat treatments as short as 10 min at 650 C substantially reduced cavitation-erosion resistance in mercury, while heat treatments at 500 and 800 C were found to be somewhat less detrimental. Overall, the results suggest that modest thermal excursions perhaps the result of a weld made at some distance to the carburized material or a brief stress relief treatment will not render the hardened layer completely ineffective but should be avoided to the greatest extent possible.

  15. Prediction of microsegregation and pitting corrosion resistance of austenitic stainless steel welds by modelling

    Energy Technology Data Exchange (ETDEWEB)

    Vilpas, M. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity

    1999-07-01

    The present study focuses on the ability of several computer models to accurately predict the solidification, microsegregation and pitting corrosion resistance of austenitic stainless steel weld metals. Emphasis was given to modelling the effect of welding speed on solute redistribution and ultimately to the prediction of weld pitting corrosion resistance. Calculations were experimentally verified by applying autogenous GTA- and laser processes over the welding speed range of 0.1 to 5 m/min for several austenitic stainless steel grades. Analytical and computer aided models were applied and linked together for modelling the solidification behaviour of welds. The combined use of macroscopic and microscopic modelling is a unique feature of this work. This procedure made it possible to demonstrate the effect of weld pool shape and the resulting solidification parameters on microsegregation and pitting corrosion resistance. Microscopic models were also used separately to study the role of welding speed and solidification mode in the development of microsegregation and pitting corrosion resistance. These investigations demonstrate that the macroscopic model can be implemented to predict solidification parameters that agree well with experimentally measured values. The linked macro-micro modelling was also able to accurately predict segregation profiles and CPT-temperatures obtained from experiments. The macro-micro simulations clearly showed the major roles of weld composition and welding speed in determining segregation and pitting corrosion resistance while the effect of weld shape variations remained negligible. The microscopic dendrite tip and interdendritic models were applied to welds with good agreement with measured segregation profiles. Simulations predicted that weld inhomogeneity can be substantially decreased with increasing welding speed resulting in a corresponding improvement in the weld pitting corrosion resistance. In the case of primary austenitic

  16. Fracture resistance of 3 types of primary esthetic stainless steel crowns.

    Science.gov (United States)

    Beattie, Sean; Taskonak, Burak; Jones, James; Chin, Judith; Sanders, Brian; Tomlin, Angela; Weddell, James

    2011-01-01

    Demand is increasing for esthetic restorations in pediatric dentistry. When full coverage is indicated, one option is to use esthetic stainless steel crowns (SSCs). However, this type of crown is prone to fracture. The purpose of this study was to evaluate the fracture resistance of 3 types of esthetic SSCs. Esthetic SSCs for first primary mandibular molars were cemented to idealized epoxy dies with glass ionomer cement. The die-crown units were fractured on a universal testing machine. The force was delivered by a stainless steel ball fixture, set in a uniaxial lever to replicate a cusp contact, with a crosshead speed of 1 mm/min. The differences among the 3 types of crown, in terms of force required to fracture, were compared statistically by 1-way analysis of variance. Pairwise comparisons were performed with Fisher's protected least significant difference test, at an overall significance level of 5%. The force required to fracture, expressed as average ± standard error, did not differ significantly among the 3 brands of esthetic SSCs: 1730 N ± 50 N, 1826 N ± 62 N and 1671 N ± 68 N, respectively (p = 0.19), well below the maximum bite force of pediatric patients determined in a previous study. Esthetic SSCs should be able to resist occlusal forces over short clinical periods. However, long-term occlusal loading and fatigue failures should be taken into account when evaluating the success of this type of crown.

  17. Evaluation of the electrical conductivity and corrosion resistance for layers deposited via sputtering on stainless steel

    Science.gov (United States)

    Blanco, J.; Salas, Y.; Jiménez, C.; Pineda, Y.; Bustamante, A.

    2017-12-01

    In some Engineering fields, we need that conductive materials have a mechanic performance and specific electrical for that they maintain conditions or corrosive attack if they are in the environment or if they are closed structure. The stainless steels have an inert film on their surface and it has the function to act in contrast to external agents who generates the corrosion, especially for stings, spoiling the film until to fail. We found a solution taking into account the electrical performance and the anticorrosive; into the process we put recovering of specific oxides on, stainless steel using the method of sputtering with Unbalanced Magnetron, (UBM) varying the oxygen in the reactive environment. The coating obtained had a thickness one micron approximately and we saw on serious structural uniformity [1]. The corrosion resistance was evaluated through the potentiodynamics polarization and electrochemical spectroscopy impedance in NACL according to the standard. The cathode protection is the most important method employed for the corrosion prevention of metallic structures in the soil or immersed on the water. The electrical resistivity was evaluated with the four points methods and it showed a behaviour of diode type in some substrates with a threshold potential in several volts. We noticed a simple resistance solution when it was analysed in the Nyquist graphics whit the Electrochemical Impedance Spectroscopy technique. With on equivalent circuit, for this reason we determinate a variation in the corrosion speed in almost two orders of magnitude when we analysed the potentiodynamics curve by Tafel approximation. The data obtained and analysed show that this type of surface modification maintains the conductivity condition at the interface, improving the resistance in relation whit the corrosion of these elements where the recovering allowed the ionic flow wished for overcoming threshold voltage, acting as an insulator in different cases.

  18. Influence of structure on static cracking resistance and fracture of welded joints of pipe steels of strength class K60

    Science.gov (United States)

    Tereshchenko, N. A.; Tabatchikova, T. I.; Yakovleva, I. L.; Makovetskii, A. N.; Shander, S. V.

    2017-07-01

    The static cracking resistance of a number of welded joints made from pipe steels of K60 strength class has been determined. It has been established that the deformation parameter CTOD varies significantly at identical parameters of weldability of steels. The character of fracture has been investigated and the zone of local brittleness of welded joints has been studied. It has been shown that the ability of a metal to resist cracking is determined by the austenite grain size and by the bainite morphology in the region of overheating in the heat-affected zone of a welded joint.

  19. Effect of Thermal Fields on the Structure of Corrosion-Resistant Steels Under Different Modes of Laser Treatment

    Science.gov (United States)

    Tarasova, T. V.; Gusarov, A. V.; Protasov, K. E.; Filatova, A. A.

    2017-11-01

    The influence of temperature fields on the structure and properties of corrosion-resistant chromium steels under different modes of laser treatment is investigated. A model of heat transfer under laser impact on target is used to plot thermal fields and cycles and cooling rates. It is shown that the model used for computing thermal fields gives tentative geometric sizes of the fusion zones under laser treatment and selective laser fusion. The cooling rate is shown to have decisive influence on the structure of corrosion-resistant steels after laser treatment with surface fusion in devices for pulsed, continuous, and selective laser melting.

  20. Effects of Thermal Aging on Microstructure and Corrosion Resistance of AISI 317L Steel Weld Metal in the FSW Process

    OpenAIRE

    Farneze, Humberto Nogueira; Tavares,Sérgio Souto Maior; Pardal, Juan Manuel; Londoño,Antônio José Ramírez; Pereira,Victor Ferrinho; Barbosa, Cássio

    2015-01-01

    The AISI 317L grade is an austenitic stainless steel with high Mo content (3.0 wt% min.). Due to the higher pitting resistance, this grade has replaced AISI 316L steel in many applications where the corrosion resistance is a critical property. However, the high Mo can induce phase transformations in high temperature services. In modern oil refinaries and petrochemical industries AISI 317L has been selected for temperatures as high as 550 °C. The goal of this work was to analyze the microstruc...

  1. High Thermal Conductivity and High Wear Resistance Tool Steels for cost-effective Hot Stamping Tools

    Science.gov (United States)

    Valls, I.; Hamasaiid, A.; Padré, A.

    2017-09-01

    In hot stamping/press hardening, in addition to its shaping function, the tool controls the cycle time, the quality of the stamped components through determining the cooling rate of the stamped blank, the production costs and the feasibility frontier for stamping a given component. During the stamping, heat is extracted from the stamped blank and transported through the tool to the cooling medium in the cooling lines. Hence, the tools’ thermal properties determine the cooling rate of the blank, the heat transport mechanism, stamping times and temperature distribution. The tool’s surface resistance to adhesive and abrasive wear is also an important cost factor, as it determines the tool durability and maintenance costs. Wear is influenced by many tool material parameters, such as the microstructure, composition, hardness level and distribution of strengthening phases, as well as the tool’s working temperature. A decade ago, Rovalma developed a hot work tool steel for hot stamping that features a thermal conductivity of more than double that of any conventional hot work tool steel. Since that time, many complimentary grades have been developed in order to provide tailored material solutions as a function of the production volume, degree of blank cooling and wear resistance requirements, tool geometries, tool manufacturing method, type and thickness of the blank material, etc. Recently, Rovalma has developed a new generation of high thermal conductivity, high wear resistance tool steel grades that enable the manufacture of cost effective tools for hot stamping to increase process productivity and reduce tool manufacturing costs and lead times. Both of these novel grades feature high wear resistance and high thermal conductivity to enhance tool durability and cut cycle times in the production process of hot stamped components. Furthermore, one of these new grades reduces tool manufacturing costs through low tool material cost and hardening through readily

  2. TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method

    National Research Council Canada - National Science Library

    M. Rozmus-Górnikowska; M. Blicharski

    2017-01-01

    The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT) method...

  3. Analysis of Anti-Bullet Resistance of Armored Steels of Foreign Manufacture

    Directory of Open Access Journals (Sweden)

    V. N. Zuzov

    2017-01-01

    Full Text Available The paper studies penetrating armour plates from the steel alloys such as Armox 560T, Domex protect 500, Weldox 700 E, Hardox 400, and Armstal 500, which are used for armour protection. In all tests for five different thick (6 mm, 8 mm, 10 mm, 6 + 6 mm, and 8 + 8mm plates was used one of the most common bullets, i.e. a 7.62 mm "APM2" (hard steel core bullet with an impact velocity of 830 m / s and 920 m / s. The article presents the developed rational finite element models of plates and bullets, which allow us to obtain results with acceptable accuracy and minimum time of solution using the LS-DYNA solver. Predicts the rational thickness values and the steel properties to ensure protection according to the European standard EN1063 ("BR7". Also conducts analysis of influence of the friction coefficient on the results of numerical simulation.The main results of calculations include the residual velocity and kinetic energy of the bullet after penetrating and the pattern of the plate fracture mechanism (for each plate type and thickness. As a result of the studies, it was found that the monolayer 6 mm, 8 mm and 10 mm thick plates from all the investigated steel alloys do not provide a protection level of "BR7" (with an initial bullet velocity of 830 m / s and, on the other hand, the two-layer plates from the alloys Armox 560T, Domex protect 500, and Armstal 500 with a total thickness of 12 mm provide such level of protection. It was also revealed that the influence of the coefficient of friction on the resistance to the bullet penetration is very small, so friction can be neglected.At an initial velocity of 920 m / s a bullet penetrated two-layer 6x2 mm thick plates from all the steel alloys under consideration, while with a thickness of 8x2 mm the bullet could not penetrate (except the Weldox 700E alloy plate.

  4. Analysis Of The Austenite Grain Growth In Low-Alloy Boron Steel With High Resistance To Abrasive Wear

    Directory of Open Access Journals (Sweden)

    Białobrzeska B.

    2015-09-01

    Full Text Available Today low-alloy steels with boron achieve high resistance to abrasive wear and high strength. These features are obtained by using advanced technology of manufacturing. This makes boron steels increasingly popular and their application more diverse. Application of these steels can extend the lifetime of very expensive machine construction in many industries such as mining, the automotive, and agriculture industries. An interesting subgroup of these materials is steel with boron intended for heat treatment. These steels are supplied by the manufacturer after cold or hot rolling so that it is possible for them to be heat treated in a suitable manner by the purchaser for its specific application. Very important factor that determines the mechanical properties of final product is austenite grain growth occurring during hot working process such us quenching or hot rolling. Investigation of the effect of heating temperature and holding time on the austenite grain size is necessary to understand the growth behavior under different conditions. This article presents the result of investigation of austenite grain growth in selected low-allow boron steel with high resistance to abrasive wear and attempts to describe the influence of chemical composition on this process.

  5. Study of martensitic-ferritic dual phase steels produced by hot stamping

    Science.gov (United States)

    Erişir, E.; Bilir, O. G.

    2017-02-01

    The effects of heat treatment and initial microstructure on tensile properties of 22MnB5 and 30MnB5 high-strength hot stamping steels with martensite-ferrite matrix were investigated. Hot stamping steels possessed limited elongations of about 5% in a tensile strength ranging from 1300 to 1500 MPa when quenched at temperatures above A3 temperatures. The total elongations were tried to improve by partial austenization between Ac1 and Ac3 temperature and quenching. Ac1 and Ac3 temperatures were calculated via ThermoCalc. Microstructural characterization was made by using Light Microscope and Scanning Electron Microscope. Microstructure is composed of ferrite+martensite. It was seen that annealing temperature affects the volume fraction of phases. It was concluded that initial microstructure is an important parameter for the final microstructure. This method can be used for automobile parts which require higher TE with sufficient yield and tensile strength. Also this process may be a way of using Zn coated steel sheets in hot stamping process.

  6. Effect on property of HIC-Resistance of vessel steel of PWHT

    Science.gov (United States)

    Zhao, Xinyu; Zou, Yang; Qin, Liye; Lv, Yanchun

    2017-09-01

    Post-Welding Heat Treatment (PWHT) is usually taken after welding and joining of vessel steel, which effects the mechanical and Hydrogen Induced Cracking (HIC) resistance property of vessel plates. Simulating PWHT experiment was taken to research on the effect on mechanical property and HIC-resistance of PWHT of vessel plates. Some conclusions can be summarized as following. Comparing with the normalizing samples, the tensile strength of the samples after PWHT with holding time of 2h, 6h and 20h decreases by 27MPa, 44MPa and 47MPa. Ductile Brittle Transition Temperature (DBTT) of the normalizing samples was almost close to those of the samples after PWHT. But the impact energy of samples at 0°C increased with rise of PWHT holding time. And the hardness of samples decreases with rise of PWHT holding time. As shown in morphology structure, the precipitation of carbonide increases with the rise of holding time of PWHT, which decreases the strength and hardness of samples and raises the impact energy. But PWHT has a little effect on HIC-Resistance, which means PWHT don't deteriorate property of HIC-Resistance of vessel plates severely.

  7. Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings.

    Science.gov (United States)

    Eric Jones, John; Chen, Meng; Yu, Qingsong

    2014-10-01

    To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20-25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH₃/O₂ plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O- and N-contents on the surfaces were substantially increased after NH₃/O₂ plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH₃/O₂ plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. © 2014 Wiley Periodicals, Inc.

  8. Corrosion resistance improvement for 316L stainless steel coronary artery stents by trimethylsilane plasma nanocoatings

    Science.gov (United States)

    Jones, John Eric; Chen, Meng; Yu, Qingsong

    2015-01-01

    To improve their corrosion resistance and thus long-term biocompatibility, 316L stainless steel coronary artery stents were coated with trimethylsilane (TMS) plasma coatings of 20–25 nm in thickness. Both direct current (DC) and radio-frequency (RF) glow discharges were utilized for TMS plasma coatings and additional NH3/O2 plasma treatment to tailor the surface properties. X-ray photoelectron spectroscopy (XPS) was used to characterize the coating surface chemistry. It was found that both DC and RF TMS plasma coatings had Si- and C-rich composition, and the O-and N-contents on the surfaces were substantially increased after NH3/O2 plasma treatment. Surface contact angle measurements showed that DC TMS plasma nanocoating with NH3/O2 plasma treatment generated very hydrophilic surface. The corrosion resistance of TMS plasma coated stents was evaluated through potentiodynamic polarization and electro-chemical impedance spectroscopy (EIS) techniques. The potentiodynamic polarization demonstrated that the TMS plasma coated stents imparted higher corrosion potential and pitting potential, as well as lower corrosion current densities as compared with uncoated controls. The surface morphology of stents before and after potentiodynamic polarization testing was analyzed with scanning electron microscopy, which indicated less corrosion on coated stents than uncoated controls. It was also noted that, from EIS data, the hydrophobic TMS plasma nanocoatings showed stable impedance modulus at 0.1 Hz after 21 day immersion in an electrolyte solution. These results suggest improved corrosion resistance of the 316L stainless steel stents by TMS plasma nanocoatings and great promise in reducing and blocking metallic ions releasing into the bloodstream. PMID:24500866

  9. Evaluation of Joint Performance on High Nitrogen Stainless Steel Which is Expected to Have Higher Allergy Resistance

    Science.gov (United States)

    Nakano, Kouichi

    Austenitic stainless steel, which includes nickel for stabilizing austenitic structure, is used for various purposes, for example, for structural material, corrosion-resistant material, biomaterial etc. Nickel is set as one of the rare metals and economizing on nickel as the natural resources is required. On the other hand, nickel is one of the metals that cause metallic allergy frequently. Therefore, high nitrogen stainless steel, where nitrogen stabilizes austenitic structure instead of nickel, has been developed in Japan and some of the foreign countries for the above reason. When high nitrogen stainless steel is fused and bonded, dissolved nitrogen is released to the atmospheric area, and some of the material properties will change. In this study, we bonded high nitrogen stainless steel by stud welding process, which is able to bond at short time, and we evaluate joint performance. We have got some interesting results from the other tests and examinations.

  10. Passive behaviour of alloy corrosion-resistant steel Cr10Mo1 in simulating concrete pore solutions with different pH

    Energy Technology Data Exchange (ETDEWEB)

    Ai, Zhiyong, E-mail: 230139452@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); Jiang, Jinyang, E-mail: jiangjinyang16@163.com [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); Sun, Wei, E-mail: sunwei@seu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); Song, Dan, E-mail: songdancharls@hhu.edu.cn [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China); College of Mechanics and Materials, Hohai University, Nanjing 210098, Jiangsu (China); Ma, Han, E-mail: mahan-iris@shasteel.cn [Research Institute of Jiangsu Shasteel Iron and Steel, Zhangjiagang 215625, Jiangsu (China); Zhang, Jianchun, E-mail: Zhangjc-iris@shasteel.cn [Research Institute of Jiangsu Shasteel Iron and Steel, Zhangjiagang 215625, Jiangsu (China); Wang, Danqian, E-mail: wonderbaba@126.com [School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu (China); Jiangsu Key Laboratory of Construction Materials, Nanjing 211189, Jiangsu (China)

    2016-12-15

    Highlights: • A new alloy corrosion-resistant steel Cr10Mo1 is developed for reinforcing rebar of concrete in severe environments. • The effects of pH on the passive behaviour of Cr10Mo1 steel compared with plain carbon steel were studied systematically by electrochemical techniques and surface analysis. • The mechanism for self-reinforcing passivity against carbonation of the corrosion-resistant steel is revealed. - Abstract: The passive behaviour of new alloy corrosion-resistant steel Cr10Mo1 and plain carbon steel (as a comparison) in simulating concrete pore solutions of different pH (ranging from 13.5 to 9.0) under open circuit potential conditions, was evaluated by various electrochemical techniques: potentiodynamic polarization, capacitance measurements and electrochemical impedance spectroscopy. The chemical composition and structure of passive films were investigated by X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The electrochemical responses of passive films show that Cr10Mo1 steel has an increasing passivity with pH decreasing while carbon steel dose conversely, revealing carbonation does no negative effect on passivation of the corrosion-resistant steel. SIMS reveals that the passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer mainly consisting of Fe oxides and hydroxides, and an inner layer enriched in Cr species, while only a Fe-concentrated layer for carbon steel. According to the XPS analysis results, as the pH decreases, more stable and protective Cr oxides are enriched in the film on Cr10Mo1 steel while Fe oxides gradually decompose. Higher content of Cr oxides in the film layer provides Cr10Mo1 corrosion-resistant steel more excellent passivity at lower pH.

  11. Isolation of a sulfide-producing bacterial consortium from cooling-tower water: Evaluation of corrosive effects on galvanized steel.

    Science.gov (United States)

    Ilhan-Sungur, Esra; Ozuolmez, Derya; Çotuk, Ayşın; Cansever, Nurhan; Muyzer, Gerard

    2017-02-01

    Sulfidogenic Clostridia and sulfate reducing bacteria (SRB) often cohabit in nature. The presence of these microorganisms can cause microbially influenced corrosion (MIC) of materials in different ways. To investigate this aspect, bacteria were isolated from cooling tower water and used in corrosion tests of galvanized steel. The identity of the isolates was determined by comparative sequence analysis of PCR-amplified 16S rDNA gene fragments, separated by denaturing gradient gel electrophoresis (DGGE). This analysis showed that, in spite of the isolation process, colonies were not pure and consisted of a mixture of bacteria affiliated with Desulfosporosinus meridiei and Clostridium sp. To evaluate the corrosive effect, galvanized steel coupons were incubated with a mixed culture for 4, 8, 24, 72, 96, 168, 360 and 744 h, along with a control set in sterile culture medium only. The corrosion rate was determined by weight loss, and biofilm formation and corroded surfaces were observed by scanning electron microscopy (SEM). Although the sulfide-producing bacterial consortium led to a slight increase in the corrosion of galvanized steel coupons, when compared to the previous studies it can be said that Clostridium sp. can reduce the corrosive effect of the Desulfosporosinus sp. strain. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Resistance to Abrasive Wear and Volume Fraction of Carbides in Cast High-manganese Austenitic Steel with Composite Structure

    Directory of Open Access Journals (Sweden)

    Tęcza G.

    2015-12-01

    Full Text Available Cast Hadfield steel is characterised by high abrasion resistance, provided, however, that it is exposed to the effect of dynamic loads. During abrasion without loading, e.g. under the impact of loose sand jet, its wear resistance drops very drastically. To increase the abrasion resistance of this alloy under the conditions where no pressure is acting, primary vanadium carbides are formed in the metallurgical process, to obtain a composite structure after the melt solidification. The primary, very hard, carbides uniformly distributed in the austenitic matrix are reported to double the wear resistance of samples subjected to the effect of a silicon carbide-water mixture.

  13. Improvement of wear resistance for C45 steel using plasma nitriding, nitrocarburizing and nitriding/ manganese phosphating duplex treatment

    Science.gov (United States)

    Doan, T. V.; Kusmič, D.; Pospíchal, M.; Dobrocký, D.

    2017-02-01

    This article focuses on effect of plasma nitriding, nitrocarburizing and nitriding/manganese phosphating duplex treatments to wear resistance of C45 steel substrate. The wear test “ball on disc” was conducted to evaluate the coefficient of friction and wear rate using the BRUKER UMT-3 tribometer. The analysis results indicated that nitrocarburizing obtained the best wear resistance; the worst wear resistance was plasma nitriding. Manganese phosphating coating enabled to reduce the coefficient of friction enhanced wear resistance nitrided layer. The used surface treatments also improve non-equal wear of tempered surface over the sliding track.

  14. Investigation of pitting resistance in ultra clean IQ-Steel vs commonly used conventional steel; 158Q vs 16MnCr5 : Back-to-back pitting tests

    OpenAIRE

    Bergseth, Ellen; Sosa, Mario; Andersson, Martin; Olofsson, Ulf

    2015-01-01

    KTH Machine Design has conducted pitting tests on gears made out of two different types of steel in a standard back-to-back pitting test rig (FZG). The tested gears were produced from Ovako’s IQ-Steel in grade 158Q and compared to the behaviour of a reference steel, commonly used conventional steel in grade 16MnCr5 (reference steel, RS). The test method is a mechanical test procedure generally used to determine the pitting load capacity of gear transmission lubricants, but in this study the p...

  15. Investigation of coatings of austenitic steels produced by supersonic laser deposition

    Science.gov (United States)

    Gorunov, A. I.; Gilmutdinov, A. Kh.

    2017-02-01

    The structure and properties of stainless austenitic steel coatings obtained by the supersonic laser deposition are studied in the paper. Implantation of the powder particles into the substrate surface and simultaneous plastic deformation at partial melting improved the mechanical properties of the coatings - tensile strength limit was 650 MPa and adhesion strength was 105 MPa. It was shown that insufficient laser power leads to disruption of the deposition process stability and coating cracking. Surface temperature increase caused by laser heating above 1300 °C resulted in coating melting. The X-ray analysis showed that radiation intensifies the cold spray process and does not cause changes in the austenitic base structure.

  16. Mechanically robust superhydrophobic steel surface with anti-icing, UV-durability, and corrosion resistance properties.

    Science.gov (United States)

    Wang, Nan; Xiong, Dangsheng; Deng, Yaling; Shi, Yan; Wang, Kun

    2015-03-25

    A superhydrophobic steel surface was prepared through a facile method: combining hydrogen peroxide and an acid (hydrochloric acid or nitric acid) to obtain hierarchical structures on steel, followed by a surface modification treatment. Empirical grid maps based on different volumes of H2O2/acid were presented, revealing a wettability gradient from "hydrophobic" to "rose effect" and finally to "lotus effect". Surface grafting has been demonstrated to be realized only on the oxidized area. As-prepared superhydrophobic surfaces exhibited excellent anti-icing properties according to the water-dripping test under overcooled conditions and the artificial "steam-freezing" (from 50 °C with 90% humidity to the -20 °C condition) test. In addition, the surfaces could withstand peeling with 3M adhesive tape at least 70 times with an applied pressure of 31.2 kPa, abrasion by 400 grid SiC sandpaper for 110 cm under 16 kPa, or water impacting for 3 h without losing superhydrophobicity, suggesting superior mechanical durability. Moreover, outstanding corrosion resistance and UV-durability were obtained on the prepared surface. This successful fabrication of a robust, anti-icing, UV-durable, and anticorrosion superhydrophobic surface could yield a prospective candidate for various practical applications.

  17. Boron effects on creep rupture strength of W containing advanced ferritic creep resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Mito, N.; Hasegawa, Y. [Tohoku Univ., Sendai (Japan)

    2010-07-01

    The creep strength in ferritic creep resistant steels is increased by boron addition. However, the strengthening mechanisms have not yet been studied. This study clarifies the strengthening mechanism of 9% chromium steels with 10{proportional_to}100ppm boron and 0.5{proportional_to}2.0mass% tungsten in the laboratory. The strengthening effect of simultaneous addition of boron and tungsten was analyzed by hardenability, room-temperature strength and creep tests at 650 C. Changes in the microstructure as a result of the addition of boron and tungsten were also examined by optical microscope and transmission electron microscope (TEM). In addition, Alpha-ray Track Etching (ATE) method was used to detect the boron distribution and analyze the mechanisms change in the mechanical properties. Boron addition did not affect room-temperature strength, however, simultaneous addition of boron and tungsten increased room-temperature and high-temperature strength. According to ATE analysis, boron exists at the grain boundary. Therefore, synergistic effects of boron and tungsten on the creep strength suggest the tungsten precipitates stabilization by boron at the grain boundary. (orig.)

  18. On the prediction of long term creep strength of creep resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Mi; Wang, Qiao; Song, Xin-Li; Jia, Juan; Xiang, Zhi-Dong [Wuhan University of Science and Technology (China). The State Key Laboratory of Refractories and Metallurgy

    2016-02-15

    When the conventional power law creep equation is applied to rationalise the creep data of creep resistant steels, its parameters depend strongly on stress and temperature and hence cannot be used to predict long term creep properties. Here, it is shown that this problem can be resolved if it is modified to satisfy two boundary conditions, i.e. when σ (stress) = 0, ε{sub min} (minimum creep rate) = 0, and when σ = σ{sub TS} (tensile stress at creep temperature T), ε{sub min} = ∞. This can be achieved by substituting the reference stress σ{sub 0} in the conventional equation by the term (σ{sub TS} - σ). The new power law creep equation describing the stress and temperature dependence of minimum creep rate can then be applied to predict long term creep strength from data of short term measurements. This is demonstrated using the creep and tensile strength data measured for 11Cr-2W-0.4Mo-1Cu-Nb-V steel (tube).

  19. Model of parameters controlling resistance of pipeline steels to hydrogen-induced cracking

    KAUST Repository

    Traidia, Abderrazak

    2014-01-01

    NACE MR0175/ISO 15156-2 standard provides test conditions and acceptance criteria to evaluate the resistance of carbon and low-alloy steels to hydrogen-induced cracking (HIC). The second option proposed by this standard offers a large flexibility on the choice of test parameters (pH, H2S partial pressure, and test duration), with zero tolerance to HIC initiation as an acceptance condition. The present modeling work is a contribution for a better understanding on how the test parameters and inclusion size can influence HIC initiation, and is therefore of potential interest for both steel makers and endusers. A model able to link the test operating parameters (pH, partial pressure of H2S, and temperature) to the maximum hydrogen pressure generated in the microstructural defects is proposed. The model results are then used to back calculate the minimum fracture toughness below which HIC extends. A minimum fracture toughness of 400 MPa√mm, at the segregation zone, prevents HIC occurrence and leads to successfully pass the HIC qualification test, even under extreme test conditions. The computed results show that the maximum generated pressure can reach up to 1,500 MPa. The results emphasize that the H2S partial pressure and test temperature can both have a strong influence on the final test results, whereas the influence of the pH of the test solution is less significant. © 2014, NACE International.

  20. Resistance of bacterial biofilms formed on stainless steel surface to disinfecting agent.

    Science.gov (United States)

    Królasik, Joanna; Zakowska, Zofia; Krepska, Milena; Klimek, Leszek

    2010-01-01

    The natural ability of microorganisms for adhesion and biofilm formation on various surfaces is one of the factors causing the inefficiency of a disinfection agent, despite its proven activity in vitro. The aim of the study was to determine the effectiveness of disinfecting substances on bacterial biofilms formed on stainless steel surface. A universally applied disinfecting agent was used in the tests. Bacterial strains: Listeria innocua, Pseudomonas putida, Micrococcus luteus, Staphylococcus hominis strains, were isolated from food contact surfaces, after a cleaning and disinfection process. The disinfecting agent was a commercially available acid specimen based on hydrogen peroxide and peroxyacetic acid, the substance that was designed for food industry usage. Model tests were carried out on biofilm formed on stainless steel (type 304, no 4 finish). Biofilms were recorded by electron scanning microscope. The disinfecting agent in usable concentration, 0.5% and during 10 minutes was ineffective for biofilms. The reduction of cells in biofilms was only 1-2 logarithmic cycles. The use of the agent in higher concentration--1% for 30 minutes caused reduction of cell number by around 5 logarithmic cycles only in the case of one microorganism, M. luteus. For other types: L. innocua, P. putida, S. hominis, the requirements placed on disinfecting agents were not fulfilled. The results of experiments proved that bacterial biofilms are resistant to the disinfectant applied in its operational parameters. Disinfecting effectiveness was achieved after twofold increase of the agent's concentration.

  1. Investigation of Parent Austenite Grains from Martensite Structure Using EBSD in a Wear Resistant Steel.

    Science.gov (United States)

    Gyhlesten Back, Jessica; Engberg, Göran

    2017-04-26

    Crystallographic reconstruction of parent austenite grain boundaries from the martensitic microstructure in a wear resistant steel was carried out using electron backscattered diffraction (EBSD). The present study mainly aims to investigate the parent austenite grains from the martensitic structure in an as-rolled (reference) steel sample and samples obtained by quenching at different cooling rates with corresponding dilatometry. Subsequently, this study is to correlate the nearest cooling rate by the dilatometer which yields a similar orientation relationship and substructure as the reference sample. The Kurdjumov-Sachs orientation relationship was used to reconstruct the parent austenite grain boundaries from the martensite boundaries in both reference and dilatometric samples using EBSD crystallographic data. The parent austenite grain boundaries were successfully evaluated from the EBSD data and the corresponding grain sizes were measured. The parent austenite grain boundaries of the reference sample match the sample quenched at 100 °C/s (CR100). Also the martensite substructures and crystallographic textures are similar in these two samples. The results from hardness measurements show that the reference sample exhibits higher hardness than the CR100 sample due to the presence of carbides in the reference sample.

  2. Microbiological influenced corrosion resistance characteristics of a 304L-Cu stainless steel against Escherichia coli.

    Science.gov (United States)

    Nan, Li; Xu, Dake; Gu, Tingyue; Song, Xiu; Yang, Ke

    2015-03-01

    Cu-bearing antibacterial stainless steels have been gaining popularity in recent years due to their strong antibacterial performances. However, only a few studies were reported for their actual performances against microbiologically influenced corrosion (MIC). In this study, electrochemical methods and surface analytical techniques were applied to study the MIC resistance characteristics of a 304L-Cu stainless steel (SS) against Escherichia coli in comparison with 304L SS as control. Corrosion tests for specimens after a 21-day exposure to a Luria-Bertani (LB) culture medium with E. coli demonstrated that the 304L-Cu SS considerably reduced the maximum MIC pit depth and the specific weight loss compared with 304L SS (8.3μm and 0.2mg/cm(2) vs. 13.4μm and 0.6mg/cm(2)). Potentiodynamic polarization tests showed that the corrosion current density of the 304L-Cu SS was as much as 4 times lower than that of the 304L SS, indicating that the 304L-Cu SS is a better choice for applications in MIC-prone environments. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. 76 FR 21332 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2011-04-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on corrosion...

  4. 76 FR 17381 - Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of...

    Science.gov (United States)

    2011-03-29

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Certain Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Notice of Final Results of the Sixteenth Administrative Review Correction In notice document 2011...

  5. 75 FR 25841 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2010-05-10

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on corrosion...

  6. 77 FR 25405 - Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea: Extension of Time...

    Science.gov (United States)

    2012-04-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF COMMERCE International Trade Administration Corrosion-Resistant Carbon Steel Flat Products From the Republic of Korea...'') published a notice of initiation of the administrative review of the antidumping duty order on corrosion...

  7. The softened heat-affected zone in resistance spot welded tailor hardened boron steel: a material model for crash simulation

    NARCIS (Netherlands)

    Eller, Tom; Greve, L; Andres, M.T.; Medricky, M; Geijselaers, Hubertus J.M.; Meinders, Vincent T.; van den Boogaard, Antonius H.

    2016-01-01

    A hardness-based model for tailor hardened boron steel is presented that takes into account the softened heat-affected zone of resistance spot welds. The computational model is designed for crashworthiness simulation of fully and partially hardened components obtained by tailored tooling. Five

  8. Effect of internal short fibers, steel reinforcement, and surface layer on impact and penetration resistance of concrete

    Directory of Open Access Journals (Sweden)

    Ali Abd_Elhakam Aliabdo

    2013-09-01

    Full Text Available This paper presents an experimental program to investigate the impact and penetration resistance of concrete. The research work is divided into two approaches. These approaches are effect of concrete constituents and effect of surface layer. Effect of concrete aggregate type, w/c ratio, fiber type, fiber shape, fiber volume fraction, and steel reinforcement is considered in the first approach. The second approach includes using fiber reinforced concrete and glass fiber reinforced polymer as surface layers. The evaluating tests include standard impact test according to ASTM D 1557 and suggested simulated penetration test to measure the impact and penetration resistance of concrete. The test results of plain and fibrous concrete from ASTM D 1557 method indicated that steel fiber with different configurations and using basalt have a great positive effect on impact resistance of concrete. Moreover, the simulated penetration test indicates that steel fibers are more effective than propylene fibers, type of coarse aggregate has negligible effect, and steel fiber volume fraction has a more significant influence than fiber shape for reinforced concrete test panels. Finally, as expectable, surface properties of tested concrete panels have a significant effect on impact and penetration resistance.

  9. Alloy 31, a new 6 moly stainless steel with improved corrosion resistance in seawater

    Energy Technology Data Exchange (ETDEWEB)

    Jasner, M.; Heubner, U. [Krupp VDM GmbH, Werdohl (Germany)

    1995-10-01

    Alloy 31--UNS N08031--31Ni-27Cr-6.5Mo-1.2Cu-0.2N-balance iron--is an advanced 6 Mo stainless steel with increased chromium and nickel, contents for seawater service. In hot seawater the pitting potential of alloy 31 remains high up to 90 C (194 F). Investigations of resistance to crevice corrosion in real piping systems in natural seawater, both North Sea and Baltic Sea, show that the threshold conditions for alloy 31 in chlorinated seawater (North Sea) are at 40 C and 1 ppm chlorine well superior to the 6 Mo stainless grades being currently in use. In addition, alloy 31 shows an excellent resistance to corrosion versus both hot reducing media (e.g. H{sub 2}SO{sub 4}) and hot oxidizing media (e.g. HNO{sub 3}). The combination of high resistance to localized corrosion vs. hot chloride-bearing cooling waters including seawater and aggressive oxidizing and reducing hot corrosive media is a unique feature of alloy 31. Alloy 31 is recommended for the construction of heat exchangers, process coolers and piping systems. The material is supplied in a number of semifinished products such as seamless and welded pipes, fittings, flanges, forged bars, plate, sheet, strip, wire and prefabricated piping systems.

  10. Wear Resistance of Steels with Surface Nanocrystalline Structure Generated by Mechanical-Pulse Treatment

    Science.gov (United States)

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha

    2017-02-01

    The influence of the surface mechanical-pulse treatment based on high-speed friction with a rapid cooling by the technological environment on the wear resistance of medium- and high-carbon steels was considered. The treatment due to a severe plastic deformation enabled obtaining the nanocrystalline structure with a grain size of 14-40 nm. A high positive effect of this treatment was obtained not only because of metal nanocrystallization but also thanks to other factors, namely, structural-phase transformations, carbon saturation of the surface due to decomposition of the coolant and the friction coefficient decrease. Higher carbon content leads to better strengthening of the surface, and its microhardness can reach 12 GPa.

  11. 34CrMo4 steel resistance against the SSC after controlled cooling process

    Directory of Open Access Journals (Sweden)

    Pavel Kučera

    2014-04-01

    Full Text Available The sulphide stress cracking corrosion resistance of 34CrMo4 steel after the accelerated cooling process under the Ar3 temperature was investigated. Two modes of heat treatment were applied to achieve homogeneous microstructure and at least partially eliminated segregation banding. First mode was based on the cooling up to the 420 °C on the air and subsequent cooling in the quenching bath. Second mode was similar except the temperature of cooling on the air, which was set up to the 460 °C. Afterward in both cases, the stress relief annealing was applied. Both modes of heat treatment resulted in the significantly banded microstructure based on the pearlite, ferrite and modified lower portion of accicular ferrite. The differences in mechanical properties of both cases of heat treatment were minimal. The SSC loading times to failure of both sets did not lead to important differences.

  12. A novel method to prepare superhydrophobic, UV resistance and anti-corrosion steel surface

    KAUST Repository

    Isimjan, Tayirjan T.

    2012-11-01

    Both TiO 2 and SiO 2 coated steel surfaces containing micro- and nanoscale binary structures with different surface roughness were successfully fabricated by means of a facile layer by layer deposition process followed by heat treatment. The resulting surfaces were modified by the low free energy chemical PTES (1H,1H,2H,2H-Perfluorodecyltriethoxysilane). The experimental results of wettability exhibit that such modified surfaces have a strong repulsive force to water droplets, their static contact angles exceed 165°, receding angle>160°, advanced angles>170° and slide angle<1°. The resulting surfaces not only exhibit superhydrophobic properties but also show strong UV resistance (after coating SiO 2 on top of TiO 2) and strong stability to various solvents including 0.01% HCl solution. © 2012 Elsevier B.V.

  13. Wear Resistance of Steel 20MnCr5 After Surfacing with Micro-jet Cooling

    Directory of Open Access Journals (Sweden)

    Tarasiuk W.

    2016-09-01

    Full Text Available This paper presents results of experimental research concerning the impact of an innovative method of micro-jet cooling on the padding weld performed with MIG welding. Micro-jet cooling is a novel method patented in 2011. It enables to steer the parameters of weld cooling in a precise manner. In addition, various elements which may e.g. enhance hardness or alter tribological properties can be entered into its top surface, depending on the applied cooling gas. The material under study was steel 20MnCr5, which was subject to the welding process with micro-jet cooling and without cooling. Nitrogen was used as a cooling gas. The main parameter of weld assessment was wear intensity. The tests were conducted in a tribological pin-on-disc type position. The following results exhibit growth at approximately 5% in wear resistance of padding welds with micro-jet cooling.

  14. Enhancement of cavitation erosion resistance of 316 L stainless steel by adding molybdenum.

    Science.gov (United States)

    Li, D G; Chen, D R; Liang, P

    2017-03-01

    The influence of Mo on ultrasonic cavitation erosion of 316 L stainless steel in 3.5% NaCl solution were investigated using an ultrasonic cavitation erosion (CE) facility. The morphologies of specimen after cavitation erosion were observed by scanning electron microscopy (SEM). The results showed that the addition of Mo can sharply decrease the mean depth of erosion (MDE) of 316 L SS, implying the increased resistance of cavitation erosion. In order to better understanding the influence of Mo on the cavitation erosion of 316 L SS, the semi-conductive property of passive films on 316 L SS containing different concentrations of Mo were studied by Mott-Schottky plot. Based on Mott-Schottky results and semiconductor physics, a physical model was proposed to explain the effect mechanism of Mo on cavitation erosion of 316 L SS. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. TEM characterization of microstructure evolution of 12%Cr heat resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, D.; Prat, O.; Sauthoff, G. [Max-Planck-Institut fuer Eisenforschung GmbH, Duesseldorf (Germany); Garcia, J. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Kaysser-Pyzalla, A.R. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Berlin (Germany); Bochum Univ. (Germany)

    2010-07-01

    A detailed characterization of the microstructure evolution of 12%Cr heat resistant steels at different creep times (100 MPa / 650 C / 8000 h) were carried out by scanning transmission electron microscopy (STEM). The results of the microstructure analysis are correlated with the mechanical properties in order to investigate the influence of different precipitates (especially M{sub 23}C{sub 6}) on the creep strength of the alloys. Precipitation of Laves phase and Z-phase was observed after several hours creep time. Very few Z-phase of the type Cr(V,Ta)N nucleating from existing (V,Ta)(C,N) was observed. Both alloys show growth and coarsening of Laves phase, meanwhile the MX carbonitrides present a very slow growth and coarsening rate. Alloys containing Laves phase, MX and M{sub 23}C{sub 6} precipitates show best creep properties. (orig.)

  16. Design and characterization of microstructure evolution during creep of 12% Cr heat resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Rojas, D. [Max Planck Institute fuer Eisenforschung GmbH, Max Planck Str. 1, 40237 Duesseldorf (Germany); Garcia, J., E-mail: jose.garcia@helmholtz-berlin.de [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Prat, O. [Max Planck Institute fuer Eisenforschung GmbH, Max Planck Str. 1, 40237 Duesseldorf (Germany); Carrasco, C. [Universidad de Concepcion, Departamento de Ingenieria de Materiales, Edmundo Larenas 270, Concepcion (Chile); Sauthoff, G. [Max Planck Institute fuer Eisenforschung GmbH, Max Planck Str. 1, 40237 Duesseldorf (Germany); Kaysser-Pyzalla, A.R. [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin (Germany); Ruhr Universitaet Bochum, Universitaetstr. 150 IA2, 44780 Bochum (Germany)

    2010-06-25

    12% Cr heat resistant steels with a fine dispersion of nano precipitates were designed supported by thermodynamic modeling. A detailed characterization of the microstructure evolution at different creep times (100 MPa/650 deg. C/8000 h) was carried out by scanning transmission electron microscopy (STEM). The results of the microstructure analysis are correlated with the mechanical properties in order to investigate the influence of different precipitates (especially M{sub 23}C{sub 6}) on the creep strength of the alloys. Precipitation of Laves phase and Z-phase was observed after several hours creep time. Very few Z-phase of the type Cr(V,Ta)N nucleating from existing (V,Ta)(C,N) was observed. Both alloys show growth and coarsening of Laves phase, meanwhile the MX carbonitrides present a very slow growth and coarsening rate. Alloys containing Laves phase, MX and M{sub 23}C{sub 6} precipitates show best creep properties.

  17. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Science.gov (United States)

    Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhang, Jianli

    2017-02-01

    The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N2 in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr2N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitro`gen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T1). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N2-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential corrosion. The Cr2N precipitation led to relatively poor resistance to pitting corrosion in three HAZs and pure Ar shielding GTAW weld root. The N2-supplemented shielding gas improved pitting corrosion resistance of GTAW joint by increasing PREN of secondary austenite and suppressing Cr2N precipitation. In addition, the FCAW WM had much poorer resistance to pitting corrosion than the GTAW WM due to many O-Ti-Si-Mn inclusions. In the BM, since the austenite with lower PREN compared

  18. Thermomechanical investigation of the production process of a creep resistant martensitic steel

    Science.gov (United States)

    Gsellmann, Bernadette; Halici, Dilek; Krenmayr, Bernhard; Poletti, Cecilia; Sonderegger, Bernhard

    2017-10-01

    During the production process of creep resistant martensitic steels, the microstructure of the material undergoes a number of transformations due to thermomechanical loading. The final microstructural features have direct influence on the mechanical properties of the alloy such as creep, fatigue and corrosion resistance, as well as toughness. In order to study the effect of each production step, the thermomechanical history of the material is reproduced in a controlled manner at lab scale for detailed examination of the flow curves during hot deformation. In addition, microstructural investigations are applied to samples after each step of the simulated production process. This procedure provides an overview of the influence of processing parameters on the material's microstructure and allows the improvement of the processing steps. The objective of this work is to reproduce parts of the production and manufacturing process of forged parts and tubes in a controlled way and to study the microstructural evolution with respect to phenomena such as recrystallization and strengthening. For this purpose hot-rolled experimental 11%Cr steel is investigated using the thermomechanical simulator Gleeble®3800. The deformed samples are investigated via LOM, SEM and EBSD. For comparison, as-received samples are included in the investigations. The interpretation of the microstructural investigation and of the obtained flow curves during the hot compression tests allow conclusions on dynamic recrystallization and recovery. Results indicate dynamic recovery as main softening process for both tested temperatures, whereas the higher temperature leads to a significant formation of delta ferrite. These results allow for improved precipitation kinetic simulations, and for further optimizing the thermomechanical treatment with respect to improved microstructure.

  19. Variability of Listeria monocytogenes strains in biofilm formation on stainless steel and polystyrene materials and resistance to peracetic acid and quaternary ammonium compounds.

    Science.gov (United States)

    Poimenidou, Sofia V; Chrysadakou, Marilena; Tzakoniati, Aikaterini; Bikouli, Vasiliki C; Nychas, George-John; Skandamis, Panagiotis N

    2016-11-21

    Listeria monocytogenes is a foodborne pathogen able to tolerate adverse conditions by forming biofilms or by deploying stress resistant mechanisms, and thus manages to survive for long periods in food processing plants. This study sought to investigate the correlation between biofilm forming ability, tolerance to disinfectants and cell surface characteristics of twelve L. monocytogenes strains. The following attributes were evaluated: (i) biofilm formation by crystal violet staining method on polystyrene, and by standard cell enumeration on stainless steel and polystyrene; (ii) hydrophobicity assay using solvents; (iii) minimum inhibitory concentration (MIC) and biofilm eradication concentration (BEC) of peracetic acid (PAA) and quaternary ammonium compounds (QACs), and (iv) resistance to sanitizers (PAA 2000ppm; QACs 500ppm) of biofilms on polystyrene and stainless steel. After 72h of incubation, higher biofilm levels were formed in TSB at 20°C, followed by TSB at 37°C (P=0.087) and diluted TSB 1/10 at both 20 (P=0.005) and 37°C (P=0.004). Cells grown at 30°C to the stationary phase had significant electron donating nature and a low hydrophobicity, while no significant correlation of cell surface properties to biofilm formation was observed. Strains differed in MIC PAA and BEC PAA by 24- and 15-fold, respectively, while a positive correlation between MIC PAA and BEC PAA was observed (P=0.02). The MIC QACs was positively correlated with the biofilm-forming ability on stainless steel (P=0.03). Regarding the impact of surface type, higher biofilm populations were enumerated on polystyrene than on stainless steel, which were also more tolerant to disinfectants. Among all strains, the greatest biofilm producer was a persistent strain with significant tolerance to QACs. These results may contribute to better understanding of L. monocytogenes behavior and survival on food processing surfaces. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. High-plasticity heat-resistant 03Kh14G16N6Yu-type steels with heat-and deformation-resistant austenite

    Science.gov (United States)

    Blinov, V. M.; Bannykh, I. O.; Zvereva, T. N.

    2008-08-01

    The structure and mechanical properties of 03Kh14G16N6Yu-type austenitic steels alloyed by molybdenum, tungsten, vanadium, and zirconium are studied after normalization at 1075°C and long-term holding at 500 700°C. The chemical composition of these steels ensures the resistance of their austenite to the martensitic transformation in the temperature range from 1200 to -196°C and during cold plastic deformation at a reduction of up to 60%. The best combination of the mechanical and technological properties is achieved in a 03Kh15G17N6YuVF steel with 0.08% W and 0.12% V. Long-term (up to 1000 h) holdings at 550 750°C do not cause the precipitation of carbide, nitride, and intermetallic phases in this steel. The long-term strength of the 03Kh15G17N6YuVF steel at temperatures up to 650°C is comparable with and its plasticity and impact toughness are higher than those of high-nickel Kh16N9M2 and Kh16N12M2 steels, which are applied in the main parts of electric power installations.

  1. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiqiang; Jing, Hongyang [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Xu, Lianyong, E-mail: xulianyong@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Han, Yongdian; Zhao, Lei [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Zhang, Jianli [Welding laboratory, Offshore Oil Engineering (Qing Dao) Company, Qing Dao 266520 (China)

    2017-02-01

    Highlights: • N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the austenite. • Secondary austenite had higher Ni but lower Cr and Mo than primary austenite. • Pitting corrosion preferentially occurred at secondary austenite and Cr{sub 2}N. • Adding N{sub 2} in shielding gas improved pitting corrosion resistance of GTAW joint. • E2209T{sub 1} weld metal had very poor pitting corrosion resistance due to inclusions. - Abstract: The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N{sub 2} in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr{sub 2}N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitrogen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T{sub 1}). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential

  2. National survey of colistin resistance among carbapenemase-producing Enterobacteriaceae and outbreak caused by colistin-resistant OXA-48-producing Klebsiella pneumoniae, France, 2014.

    Science.gov (United States)

    Jayol, Aurélie; Poirel, Laurent; Dortet, Laurent; Nordmann, Patrice

    2016-09-15

    From January 2014 to December 2014, 972 consecutive non-replicate carbapenemase-producing Enterobacteriaceae isolates from colonised or infected patients were collected at the Associated French National Reference Centre as part of the French national survey on antimicrobial resistance. It included 577 Klebsiella spp. (59%), 236 Escherichia coli (24%), 108 Enterobacter spp. (11%), 50 Citrobacter spp. (5%), and a single Salmonella spp. isolate (0.1%). Of 561 K. pneumoniae isolates, 35 were found to be resistant to colistin (6.2%). PFGE analysis revealed a clonal outbreak involving 15 K. pneumoniae isolates belonging to sequence type ST11, recovered in a single hospital in the Picardie region in northern France. Those clonally related isolates showed variable levels of resistance to colistin, ranging from 4 to 64 mg/L. They harboured the blaOXA-48 carbapenemase gene and the blaCTX-M-15 extended-spectrum beta-lactamase gene. Among the 91 Enterobacter cloacae isolates, seven were resistant to colistin and produced different types of carbapenemases. Surprisingly, none of the E. coli and Citrobacter spp. isolates showed resistance to colistin. This national survey including carbapenemase-producing isolates recovered in 2014 reported a high rate of colistin resistance in K. pneumoniae and E. cloacae (6.2% and 7.7%, respectively) in France. This article is copyright of The Authors, 2016.

  3. Effect of Different Types of Toothpaste on the Frictional Resistance Between Orthodontic Stainless Steel Brackets and Wires.

    Science.gov (United States)

    Hosseinzadeh Nik, Tahereh; Hooshmand, Tabassom; Farhadifard, Homa

    2017-09-01

    The purpose of this study was to investigate the effect of different types of toothpaste on the frictional resistance between stainless steel brackets and archwires. Ninety stainless steel orthodontic brackets with stainless steel wires were bonded to bovine teeth and were divided into 6 groups for application of the following toothpastes: Colgate® Total® Advanced Whitening, Colgate® Total® Pro Gum Health, Colgate® Anticavity, Ortho.Kin®, and Sunstar GUM® Ortho toothpastes. No toothpaste was applied in the control group. Each group was brushed by a brushing machine with the use of the designated solution for 4.5 minutes. The frictional force was measured in a universal testing machine with a crosshead speed of 10 mm/minute over a 5-mm archwire. Data were analyzed using one-way analysis of variance (ANOVA) at the 0.05 significance level. The frictional resistance values of Ortho.Kin® and GUM® Ortho toothpastes and the control group were not significantly different (P>0.05). However, there were significant differences between the frictional resistance values of Colgate® Total® Pro Gum Health and Colgate® Anticavity toothpastes with that of the control group (Pstainless steel brackets and wires.

  4. Cyclotriphosphazene and TiO2 reinforced nanocomposite coated on mild steel plates for antibacterial and corrosion resistance applications

    Science.gov (United States)

    Krishnadevi, Krishnamoorthy; Selvaraj, Vaithilingam

    2016-03-01

    The mild steel surface has been modified to impart anticorrosion and antibacterial properties through a dip coating method followed by thermal curing of a mixture containing amine terminated cyclotriphosphazene and functionalized titanium dioxide nanoparticles reinforced benzoxazine based cyanate ester composite (ATCP/FTiO2/Bz-CE). The corrosion resistance behavior of coating material has been investigated by electrochemical and antibacterial studies by disc diffusion method. The nanocomposites coated mild steels have displayed a good chemical stability over long immersion in a corrosive environment. The protection efficiency has found to be high for ATCP/FTiO2/Bz-CE composites, which can be used in microelectronics and marine applications.

  5. Synergy effects of Cu and Sn on pitting corrosion resistance of ultra-purified medium chromium ferritic stainless steel

    Science.gov (United States)

    Zhang, XiangJun; Liu, ZhenYu

    2017-03-01

    The influence of combination of Cu and Sn on pitting resistance of ultra-purified medium chromium ferritic stainless steel in 3.5 wt.% NaCl at 25°C was investigated by using electrochemical method. The results show that there is synergy effect between Cu and Sn, and the strong interaction between Cu and Sn in ferritic stainless steels clearly affects their pitting corrosion behaviour in 3.5% NaCl. A mechanism of the synergy of Cu and Sn was discussed.

  6. Development of heat-resistant cast steel for exhaust manifolds. Exhaust manifold yo tainetsu chuko no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Ike, M.; Akiyama, K. (Nissan Motor Co. Ltd., Tokyo (Japan)); Otsuka, K.; Ito, K. (Hitachi Metals, Ltd., Tokyo (Japan))

    1991-07-01

    Any exhaust manifold is exposed to the severer thermal cycle condition by exhasut gas of the maximum temperature reaching near 1273K and therefore the thermal resistance reliability should be improved. A new cast heat resistant steel for the exhaust manifold which had better thermal fatigue resistance and oxidation resistance than conventional Ni-resist cast iron was developed this time. The developed material was based on the 18Cr ferritic heat resistant steel of low coefficent of thermal expansion and the oxidation resistance was improved, and further the thermal fatigue life was improved by aiming at the structural stability through elevating the transformation point to the upper limit of service temperature or more. These requirements were achieved by grasping the above mentioned characteristics of the part material and by studying the effect of main composing elements, C, N, Cr, Nb, Mo, on these characteristics. The cheaper exhaust manifold of higher thermal resistant reliability than conventional one could be put into practical use by using a newly developed casting process in addition to the use of this developed material. 7 refs., 11 figs., 5 tabs.

  7. A novel ultra-low carbon grain oriented silicon steel produced by twin-roll strip casting

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Yang, E-mail: wy069024019@163.com [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Zhang, Yuan-Xiang; Lu, Xiang; Fang, Feng; Xu, Yun-Bo; Cao, Guang-Ming; Li, Cheng-Gang [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China); Misra, R.D.K. [Laboratory for Excellence in Advanced Steel Research, Department of Metallurgical, Materials and Biomedical Engineering, University of Texas at El Paso, TX 79968 (United States); Wang, Guo-Dong [State Key Laboratory of Rolling and Automation, Northeastern University, Shenyang 110819 (China)

    2016-12-01

    A novel ultra-low carbon grain oriented silicon steel was successfully produced by strip casting and two-stage cold rolling method. The microstructure, texture and precipitate evolution under different first cold rolling reduction were investigated. It was shown that the as-cast strip was mainly composed of equiaxed grains and characterized by very weak Goss texture ({110}<001>) and λ-fiber (<001>//ND). The coarse sulfides of size ~100 nm were precipitated at grain boundaries during strip casting, while nitrides remained in solution in the as-cast strip and the fine AlN particles of size ~20–50 nm, which were used as grain growth inhibitors, were formed in intermediate annealed sheet after first cold rolling. In addition, the suitable Goss nuclei for secondary recrystallization were also formed during intermediate annealing, which is totally different from the conventional process that the Goss nuclei originated in the subsurface layer of the hot rolled sheet. Furthermore, the number of AlN inhibitors and the intensity of desirable Goss texture increased with increasing first cold rolling reduction. After secondary recrystallization annealing, very large grains of size ~10–40 mm were formed and the final magnetic induction, B{sub 8}, was as high as 1.9 T. - Highlights: • A novel chemical composition base on strip casting silicon steel was proposed. • The ultra-low carbon design could shorten the processing routes. • The novel composition and processes were beneficial to obtain more inhibitors. • The magnetic induction of grain oriented silicon steel was significantly improved.

  8. Immobilization of lead by application of soil amendment produced from vinegar residue, stainless steel slag, and weathered coal.

    Science.gov (United States)

    Pei, Guangpeng; Li, Yuxin; Zhu, Yuen; Shi, Weiyu; Li, Hua

    2017-10-01

    This paper presents a new soil amendment used for immobilization of soil Pb, produced from vinegar residue, stainless steel slag, and weathered coal. The pH value measuring, granulation and adsorption experiments were carried out to determine the optimal composition of soil amendment. Optimizing soil amendment B2 was composed of vinegar residue, weathered coal (humic acid 61.53 wt%), and stainless steel slag with the ratio of 80∶16∶4, and particle size was in the range of 2-4 mm. In the leaching column experiment, B2 addition reduced the Pb release from the soil as well as increasing leachate pH and decreasing the bioavailable Pb concentration. The leachate Pb concentration decreased with lengthened leaching time under lower pH, but such a phenomenon disappeared in the rebounding period. Compared to control, the DTPA extractable Pb content in soil decreased by 12.41, 13.20, and 8.78% with the B2 addition amount of 1.00, 2.00, and 2.00 wt%, respectively. In addition, the total Pb content of each soil layer generally rose as B2 addition increased. It was concluded that application of B2 led to lower transport and transformation of Pb in soil. Based on the single chemical extraction, the environmental risk of Pb was decreased after application of B2. Meanwhile, soil amendment was also a new way to recycle vinegar residue, stainless steel slag, and weathered coal.

  9. Control and monitoring of antimicrobial resistance in bacteria in food-producing animals in Japan

    Directory of Open Access Journals (Sweden)

    Katsuaki Sugiura

    2009-06-01

    Full Text Available Increased antimicrobial resistance in bacteria that cause infections in humans is a threat to public health. The use of antimicrobials in food-producing animals in the form of veterinary medicine and feed additives may lead to the emergence or spread of antimicrobial resistance in bacteria of animal origin. In Japan, the use of antimicrobials in food-producing animals is regulated by the Pharmaceutical Affairs Law and Feed Safety Law to minimise the risk of emergence and spread of antimicrobial resistance in bacteria. Since December 2003, all antimicrobials used in food-producing animals have been subjected to risk assessment by the Food Safety Commission. In addition, an antimicrobial resistance monitoring programme has been in place since 2000 to monitor the evolution of resistance to different antimicrobials in bacteria in food-producing animals.

  10. A comparative in vitro study of frictional resistance between lingual brackets and stainless steel archwires.

    Science.gov (United States)

    Ozturk Ortan, Yildiz; Yurdakuloglu Arslan, Tugce; Aydemir, Bulent

    2012-02-01

    Friction between archwires and labial brackets has received considerable attention; however, information on the frictional behaviour of commercially available lingual brackets is limited. The aim of this study was to investigate the frictional resistance resulting from a combination of lingual orthodontic brackets (7th Generation, STb, Magic, and In-Ovation L) and stainless steel archwires at 0, 5, and 10 degrees of second-order angulation. Each bracket type (n = 30) was tested with three different sizes of archwires. Static and kinetic frictional forces were evaluated with a universal testing machine. Statistical analysis of the data was performed with non-parametric Kruskal-Wallis and Dunn's multiple comparison tests. All tested brackets showed higher frictional forces as the wire size and second-order angulation increased. The lowest friction was found with In-Ovation L brackets and 0.016 inch archwires at 0 degrees angulation, and the greatest friction with a combination of STb brackets and 0.017 × 0.025 inch archwires at 10 degrees angulation. For all combinations, Magic and In-Ovation L brackets showed lower frictional resistance when compared with 7th Generation and STb brackets. The slot width (occluso-gingival dimension) of the brackets, measured using the optics of a microhardness machine, showed that all brackets were oversized and that Magic brackets had the largest slot width. Surface roughness of the brackets investigated using atomic force microscopy and scanning electron microscopy, demonstrated that the 7th Generation brackets had the greatest surface roughness.

  11. Corrosion resistance enhancement of SAE 1020 steel after Chromium implantation by nitrogen ion recoil

    Directory of Open Access Journals (Sweden)

    Geraldo Francisco Gomes

    2005-12-01

    Full Text Available SAE 1020 construction steel is widely used as mortar reinforcement and small machine parts, but aside good surface properties as high ductility, hardness and wear resistance, its surface is prone to severe corrosion. As it is known, Chromium in amount over 12%-13% in the Fe alloys renders them resistance to several corrosive attacks. SAE 1020 samples were recovered with Chromium film and then bombarded either by nitrogen Ion Beam (IB or Plasma Immersion Ion Implantation (PIII to recoil implant Cr atoms in the Fe matrix. Samples treated by 100 keV N+ IB showed irregular, thin Cr profile, remaining a part of the film on the surface, to about 10 nm. Samples treated by 40 kV N PIII presented Cr layer of about 18% at., ranging to around 90 nm. Cr of the film was implanted in the Fe matrix in an almost flat profile. Results of corrosion test showed good performance of the PIII treated sample. The IB treated sample showed some enhancement over the non-treated reference and the only Cr film deposited sample showed no modification on the corrosion behavior as compared to the non-treated reference sample.

  12. Pull-Out Resistance Capacity of a New Perfobond Shear Connector for Steel Pile Cap Strengthening

    Directory of Open Access Journals (Sweden)

    Young-Ho Kim

    2016-01-01

    Full Text Available This study proposes a new type of the perfobond shear connector, which can be used to strengthen the steel pile cap embedded into the structure foundation, and evaluates its pull-out resistance capacity by performing a test on ten specimens. Test parameters include the embedment length of the shear connector, existence of transverse rebars passing through holes in the shear connector, and their shape, size, and number. The pull-out load versus slip curve is plotted for all specimens, and their failure modes are identified. The effects of the test parameters on the peak pull-out load are examined in this work. The test results show that the perfobond shear connector proposed in this study can retain the peak pull-out load up to 6 times higher than the one without any holes. This indicates that the existence of holes in the shear connector enables the dowel action of concrete inside the hole, resulting in the improvement of the shear resistance capacity of the connector.

  13. Static recrystallisation of steels produced by direct strip casting – The effect of carbon and vanadium concentration

    Energy Technology Data Exchange (ETDEWEB)

    Ramajayam, M. [Institute for Frontier Materials, Deakin University, 3216 (Australia); Stanford, N. [Department of Materials Science and Engineering, Monash University, 3800 (Australia)

    2016-08-01

    Six steel alloys containing a range of carbon and vanadium concentrations have been prepared by simulated strip casting. The alloys were cold rolled and annealed to examine the recrystallisation behaviour. The annealing treatment resulted in three processes occurring concurrently: recrystallisation; spheroidisation of cementite, and precipitation of vanadium-enriched nano-precipitates. These nano-precipitates had a much higher concentration of Fe than would be expected from traditional processing methods, and this increased their maximum attainable volume fraction. In the two alloys that did not contain second phase particles, recrystallisation showed typical reaction kinetics, and the recrystallised grain size continued to increase with increasing time at temperature. However, in those alloys with second phase particles the recrystallised grains showed unusual behaviour, rapidly reaching an upper limit to their size. Continued time at temperature was not accompanied by an increase in the grain size. This growth limit has been attributed to Zener pinning, with the limiting grain size being proportional to the Zener pinning pressure. It has been proposed that the delayed recrystallisation that is typically observed in strip cast steels is likely to be the result of nano-scale precipitation which is unique to rapidly cooled materials, such as those produced by strip casting.

  14. 9-12% Cr heat resistant steels. Alloy design, TEM characterisation of microstructure evolution and creep response at 650 C

    Energy Technology Data Exchange (ETDEWEB)

    Rojas Jara, David

    2011-03-21

    This work was carried out aiming to design and characterise 9-12% Cr steels with tailormade microstructures for applications in fossil fuel fired power plants. The investigations concentrated in the design and characterisation of heat resistant steels for applications in high oxidising atmospheres (12% Cr) and 9% Cr alloys for components such as rotors (P91). ThermoCalc calculations showed to be a reliable tool for alloy development. The modeling also provided valuable information for the adjustment of the processing parameters (austenisation and tempering temperatures). Two 12% Cr heat resistant steels with a fine dispersion of nano precipitates were designed and produced supported by thermodynamic modeling (ThermoCalc). A detailed characterisation of the microstructure evolution at different creep times (100 MPa / 650 C / 8000 h) was carried out by scanning transmission electron microscopy (STEM). The results of the microstructure analysis were correlated with the mechanical properties in order to investigate the influence of different precipitates (especially M{sub 23}C{sub 6} carbides) on the creep strength of the alloys. Precipitation of Laves phase and Z-phase was observed after several hundred hours creep time. Very few Z-phase of the type Cr(V,Ta)N nucleating from existing (V,Ta)(C,N) was observed. Both alloys show growth and coarsening of Laves phase, meanwhile the MX carbonitrides present a very slow growth and coarsening rate. Alloys containing Laves phase, MX and M{sub 23}C{sub 6} precipitates show best creep properties. The influence of hot-deformation and tempering temperature on the microstructure evolution on one of the designed 12% Cr alloys was studied during short-term creep at 80-250 MPa and 650 C. Quantitative determination of dislocation density and sub-grain size in the initial microstructure and after creep was investigated by STEM combined with the high-angle annular dark-field detector (HAADF). A correlation between microstructure

  15. Permeability Study of Austenitic Stainless Steel Surfaces Produced by Selective Laser Melting

    Directory of Open Access Journals (Sweden)

    Emmanuel Segura-Cardenas

    2017-11-01

    Full Text Available Selective laser melting (SLM is emerging as a versatile process for fabricating different metal components with acceptable mechanical properties and geometrical accuracy. The process has been used in the manufacturing of several parts (e.g., aerospace or biomedical components, and offers the capability to tailor the performance of several surface and mechanical properties. In this work, permeability properties and surface roughness of stainless steel (SS316L surfaces were evaluated through experimentation with three different laser scanning patterns (chessboard, meander, and stripe, and different sloping angles between the fabricated surface and the laser beam incident on the process. Results showed that for each scanning pattern, the roughness decreased as the sloping angle increased consistently in all experimental trials. Furthermore, in the case of the permeability evaluation, the manufactured surfaces showed changes in properties for each series of experiments performed with different scanning patterns. The chessboard pattern showed a change of 67° to 107° in contact angle, while the meander and stripe patterns showed a variation in contact angle in a range of 65° to 85°. The different scanning strategies in the SLM process resulted in an alternative method for surface enhancement with different hydrophobicity properties, valuable for designing the most appropriate permeability characteristics for specific applications.

  16. Corrosion resistance of various bio-films deposited on austenitic cast steel casted by lost-wax process and in gypsum mould

    Directory of Open Access Journals (Sweden)

    J. Gawroński

    2010-01-01

    Full Text Available This work is the next of a series concerning the improvement of austenitic cast steel utility predicted for use in implantology for complicated long term implants casted by lost-wax process and in gypsum mould. Austenitic cast steel possess chemical composition of AISI 316L medical steel used for implants. In further part of present work investigated cast steel indicated as AISI 316L medical steel. Below a results of electrochemical corrosion resistance of carbon layer and bi-layer of carbon/HAp deposited on AISI 316L researches are presented. Coatings were manufactured by RF PACVD and PLD methods respectively. Obtained results, unequivocally indicates on the improvement of this type of corrosion resistance by substrate material with as deposited carbon layer. While bi-layer of carbon/HAp are characterized by very low corrosion resistance.

  17. Influence of Magnesium Ions in the Seawater Environment on the Improvement of the Corrosion Resistance of Low-Chromium-Alloy Steel

    Directory of Open Access Journals (Sweden)

    Sol-Ji Song

    2018-01-01

    Full Text Available This study examined the synergic effect of alloying the element Cr and the environmental element Mg2+ ions on the corrosion property of a low-alloy steel in seawater at 60 °C, by means of electrochemical impedance spectroscopy (EIS, linear polarization resistance (LPR tests and weight-loss tests. The Mg2+ ions in seawater played an important role in lowering the electron transfer of the rust layer in the Cr-containing steel. The corrosion resistance of the Cr-containing steel is superior to that of blank steel in Mg2+ ions containing seawater. XPS and XRD results indicated that the formation of MgFe2O4 and a mixed layer (Cr oxide + FeCr2O4 + MgCr2O4 improved the corrosion resistance of the low-alloy steel in the seawater.

  18. The microstructural evolution and elemental distribution of a 3rd generation 1 GPa advanced high strength steel during double pulse resistance spot welding

    NARCIS (Netherlands)

    Eftekharimilani, P.; van der Aa, EM; Hermans, M.J.M.; Richardson, I.M.

    2017-01-01

    This paper presents the effects of double pulse resistance spot welding (RSW) on the microstructural evolution, elemental distribution and mechanical properties of a 3rd generation 1 GPa advanced high strength steel (AHSS). In order to investigate the effect of double pulsing, the steel was exposed

  19. The effect of σ-phase precipitation at 800°C on the corrosion resistance in sea-water of a high alloyed duplex stainless steel

    NARCIS (Netherlands)

    Wilms, M.E.; Gadgil, V.J.; Krougman, J.M.; Ijsseling, F.P.

    1994-01-01

    Super-duplex stainless steels are recently developed high alloyed stainless steels that combine good mechanical properties with excellent corrosion resistance. Because of a high content of chromium and molybdenum, these alloys are susceptible to σ-phase precipitation during short exposure to

  20. The Passive Film Growth Mechanism of New Corrosion-Resistant Steel Rebar in Simulated Concrete Pore Solution: Nanometer Structure and Electrochemical Study

    Science.gov (United States)

    Jiang, Jin-yang; Wang, Danqian; Chu, Hong-yan; Ma, Han; Liu, Yao; Gao, Yun; Shi, Jinjie; Sun, Wei

    2017-01-01

    An elaborative study was carried out on the growth mechanism and properties of the passive film for a new kind of alloyed corrosion-resistant steel (CR steel). The passive film naturally formed in simulated concrete pore solutions (pH = 13.3). The corrosion resistance was evaluated by various methods including open circuit potential (OCP), linear polarization resistance (LPR) measurements, and electrochemical impedance spectroscopy (EIS). Meanwhile, the 2205 duplex stainless steel (SS steel) was evaluated for comparison. Moreover, the passive film with CR steel was studied by means of X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), Atomic Force Microscope (AFM), and the Mott‑Schottky approach. The results showed that the excellent passivity of CR steel could be detected in a high alkaline environment. The grain boundaries between the fine passive film particles lead to increasing Cr oxide content in the later passivation stage. The filling of cation vacancies in the later passivation stage as well as the orderly crystalized inner layer contributed to the excellent corrosion resistance of CR steel. A passive film growth model for CR steel was proposed. PMID:28772772

  1. Toward Improving the Type IV Cracking Resistance in Cr-Mo Steel Weld Through Thermo-Mechanical Processing

    Science.gov (United States)

    Shassere, Benjamin A.; Yamamoto, Yukinori; Babu, Sudarsanam Suresh

    2016-05-01

    Detailed microstructure characterization of Grade 91 (Modified 9Cr-1Mo, ASTM A387) steel subjected to a thermo-mechanical treatment process was performed to rationalize the cross-weld creep properties. A series of thermo-mechanical processing in the austenite phase region, followed by isothermal aging at temperatures at 973 K to 1173 K (700 °C to 900 °C), was applied to the Grade 91 steel to promote precipitation kinetics of MX (M: Nb and V, X: C and N) in the austenite matrix. Detailed characterization of the base metals after standard tempering confirmed the presence of fine MX dispersion within the tempered martensitic microstructure in steels processed at/and above 1073 K (800 °C). Relatively low volume fraction of M23C6 precipitates was observed after processing at 1073 K (800 °C). The cross-weld creep strength after processing was increased with respect to the increase of MX dispersion, indicating that these MX precipitates maintained during weld thermal cycles in the fine-grained heat-affected zone region and thereby contribute to improved creep resistant of welds in comparison to the welds made with the standard "normalization and tempering" processes. The steels processed in this specific processing condition showed improved cross-weld creep resistance and sufficient room temperature toughness. The above data are also analyzed based on existing theories of creep deformation based on dislocation climb mechanism.

  2. PERFORMANCE IMPROVEMENT OF CREEP-RESISTANT FERRITIC STEEL WELDMENTS THROUGH THERMO-MECHANICAL TREATMENT AND ALLOY DESIGN

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Yukinori [ORNL; Babu, Prof. Sudarsanam Suresh [University of Tennessee, Knoxville (UTK); Shassere, Benjamin [ORNL; Yu, Xinghua [ORNL

    2016-01-01

    Two different approaches have been proposed for improvement of cross-weld creep properties of the high temperature ferrous structural materials for fossil-fired energy applications. The traditional creep strength-enhanced ferritic (CSEF) steel weldments suffer from Type IV failures which occur at the fine-grained heat affected zone (FGHAZ). In order to minimize the premature failure at FGHAZ in the existing CSEF steels, such as modified 9Cr-1Mo ferritic-martensitic steels (Grade 91), a thermo-mechanical treatment consisting of aus-forging/rolling and subsequent aus-aging is proposed which promotes the formation of stable MX carbonitrides prior to martensitic transformation. Such MX remains undissolved during welding process, even in FGHAZ, which successfully improves the cross-weld creep properties. Another approach is to develop a new fully ferrtic, creep-resistant FeCrAl alloy which is essentially free from Type IV failure issues. Fe-30Cr-3Al base alloys with minor alloying additions were developed which achieved a combination of good oxidation/corrosion resistance and improved tensile and creep performance comparable or superior to Grade 92 steel.

  3. Development of rapidly quenched nickel-based non-boron filler metals for brazing corrosion resistant steels

    Science.gov (United States)

    Ivannikov, A.; Kalin, B.; Suchkov, A.; Penyaz, M.; Yurlova, M.

    2016-04-01

    Corrosion-resistant steels are stably applied in modern rocket and nuclear technology. Creating of permanent joints of these steels is a difficult task that can be solved by means of welding or brazing. Recently, the use rapidly quenched boron-containing filler metals is perspective. However, the use of such alloys leads to the formation of brittle borides in brazing zone, which degrades the corrosion resistance and mechanical properties of the compounds. Therefore, the development of non-boron alloys for brazing stainless steels is important task. The study of binary systems Ni-Be and Ni-Si revealed the perspective of replacing boron in Ni-based filler metals by beryllium, so there was the objective of studying of phase equilibrium in the system Ni-Be-Si. The alloys of the Ni-Si-Be with different contents of Si and Be are considered in this paper. The presence of two low-melting components is revealed during of their studying by methods of metallography analysis and DTA. Microhardness is measured and X-ray diffraction analysis is conducted for a number of alloys of Ni-Si-Be. The compositions are developed on the basis of these data. Rapidly quenched brazing alloys can be prepared from these compositions, and they are suitable for high temperature brazing of steels.

  4. Pitting corrosion resistance and bond strength of stainless steel overlay by friction surfacing on high strength low alloy steel

    Directory of Open Access Journals (Sweden)

    Amit Kumar Singh

    2015-09-01

    Full Text Available Surface modification is essential for improving the service properties of components. Cladding is one of the most widely employed methods of surface modification. Friction surfacing is a candidate process for depositing the corrosion resistant coatings. Being a solid state process, it offers several advantages over conventional fusion based surfacing process. The aim of this work is to identify the relationship between the input variables and the process response and develop the predictive models that can be used in the design of new friction surfacing applications. In the current work, austenitic stainless steel AISI 304 was friction surfaced on high strength low alloy steel substrate. Friction surfacing parameters, such as mechtrode rotational speed, feed rate of substrate and axial force on mechtrode, play a major role in determining the pitting corrosion resistance and bond strength of friction surfaced coatings. Friction surfaced coating and base metal were tested for pitting corrosion by potentio-dynamic polarization technique. Coating microstructure was characterized using optical microscopy, scanning electron microscopy and X-ray diffraction. Coatings in the as deposited condition exhibited strain-induced martensite in austenitic matrix. Pitting resistance of surfaced coatings was found to be much lower than that of mechtrode material and superior to that of substrate. A central composite design with three factors (mechtrode rotational speed, substrate traverse speed, axial load on mechtrode and five levels was chosen to minimize the number of experimental conditions. Response surface methodology was used to develop the model. In the present work, an attempt has been made to develop a mathematical model to predict the pitting corrosion resistance and bond strength by incorporating the friction surfacing process parameters.

  5. Non-Beta-Lactamase-Producing Penicillin-Resistant Enterococcus faecium in a Clinical Setting

    Directory of Open Access Journals (Sweden)

    Daniel Eymard

    1990-01-01

    Full Text Available Six clinical isolates of Enterococcus faecium highly resistant to penicillin are reported. These strains did not produce beta-lactamase and no plasmid DNA could be detected. It is postulated that the mechanism of resistance is one or more chromosomally mediated alterations of penicillin-binding proteins.

  6. mcr-1 Colistin Resistance in ESBL-Producing Klebsiella pneumoniae, France.

    Science.gov (United States)

    Caspar, Yvan; Maillet, Mylène; Pavese, Patricia; Francony, Gilles; Brion, Jean-Paul; Mallaret, Marie-Reine; Bonnet, Richard; Robin, Frédéric; Beyrouthy, Racha; Maurin, Max

    2017-05-01

    We report intestinal carriage of an extended-spectrum β-lactamase-producing Klebsiella pneumoniae strain with high-level resistance to colistin (MIC 24 mg/L) in a patient in France who had been hospitalized for fungal meningitis. The strain had the mcr-1 plasmid gene and an inactivated mgrB gene, which are associated with colistin resistance.

  7. Effect of Batch Annealing Temperature on Microstructure and Resistance to Fish Scaling of Ultra-Low Carbon Enamel Steel

    Directory of Open Access Journals (Sweden)

    Zaiwang Liu

    2017-02-01

    Full Text Available In the present work, an ultra-low carbon enamel steel was batch annealed at different temperatures, and the effect of the batch annealing temperature on the microstructure and resistance to fish scaling was investigated by optical microscopy, transmission electron microscopy, and a hydrogen permeation test. The results show that the main precipitates in experimental steel are fine TiC and coarse Ti4C2S2 particles. The average sizes of both TiC and Ti4C2S2 increase with increasing the batch annealing temperature. The resistance to fish scaling decreases with increasing the annealing temperature, which is caused by the growth of ferrite grain and the coarsening of the TiC and Ti4C2S2 particles

  8. Estimating hysteretic energy demand in steel moment resisting frames using Multivariate Adaptive Regression Spline and Least Square Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Jatin Alreja

    2015-06-01

    Full Text Available This paper uses Multivariate Adaptive Regression Spline (MARS and Least Squares Support Vector Machines (LSSVMs to predict hysteretic energy demand in steel moment resisting frames. These models are used to establish a relation between the hysteretic energy demand and several effective parameters such as earthquake intensity, number of stories, soil type, period, strength index, and the energy imparted to the structure. A total of 27 datasets (input–output pairs are used, 23 of which are used to train the model and 4 are used to test the models. The data-sets used in this study are derived from experimental results. The performance and validity of the model are further tested on different steel moment resisting structures. The developed models have been compared with Genetic-based simulated annealing method (GSA and accurate results portray the strong potential of MARS and LSSVM as reliable tools to predict the hysteretic energy demand.

  9. Mechanical And Microstructural Evaluation Of A Wear Resistant Steel; Avaliacao mecanica e microestrutural de um aco resistente ao desgaste

    Energy Technology Data Exchange (ETDEWEB)

    Santos, F.L.F. dos; Vieira, A.G.; Correa, E.C.S.; Pinheiro, I.P., E-mail: falletti@hotmail.co [Centro Federal de Educacao Tecnologica de Minas Gerais (CEFET/MG), Belo Horizonte, MG (Brazil). Dept. de Engenharia de Materiais

    2010-07-01

    In the present work, the analysis of the mechanical properties and the microstructural features of a high strength low alloy steel, containing chromium, molybdenum and boron, subjected to different heat treatments, was conducted. After austenitizing at 910 deg C for 10 minutes, three operations were carried out: oil quenching, oil quenching followed by tempering at 200 deg C for 120 minutes and austempering at 400 deg C for 5 minutes followed by water cooling. The analysis was performed through tensile and hardness tests, optical microscopy and X-ray diffraction. The bainitic structure led to high strength and toughness, both essential mechanical properties for wear resistant steels. The occurrence of allotriomorphic ferrite and retained austenite in the samples also increased the wear resistance. This phenomenon is related to the fact that both structures are able to be deformed and, in the case of the retained austenite, the transformation induced plasticity TRIP effect may take place as the material is used. (author)

  10. Current status and future prospective of advanced radiation resistant oxide dispersion strengthened steel (ARROS) development for nuclear reactor system applications

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Kyu; Noh, Sang Hoon; Kang, Suk Hoon; Park, Jin Ju; Jin, Hyun Ju; Lee, Min Ku; Jang, Jin Sugn; Rhee, Chang Kyu [Nuclear Materials Development Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-04-15

    As one of the Gen-IV nuclear energy systems, a sodium-cooled fast reactor (SFR) is being developed at the Korea Atomic Energy Research Institute. As a long-term national research project, advanced radiation resistant oxide dispersion strengthened steel (ARROS) is being developed as an in-core fuel cladding tube material for a SFR in the future. In this paper, the current status of ARROS development is reviewed and its future prospective is discussed.

  11. Current Status and Future Prospective of Advanced Radiation Resistant Oxide Dispersion Strengthened Steel (ARROS Development for Nuclear Reactor System Applications

    Directory of Open Access Journals (Sweden)

    Tae Kyu Kim

    2016-04-01

    Full Text Available As one of the Gen-IV nuclear energy systems, a sodium-cooled fast reactor (SFR is being developed at the Korea Atomic Energy Research Institute. As a long-term national research project, advanced radiation resistant oxide dispersion strengthened steel (ARROS is being developed as an in-core fuel cladding tube material for a SFR in the future. In this paper, the current status of ARROS development is reviewed and its future prospective is discussed.

  12. Effects of Ultrasonic Nanocrystal Surface Modification on the Residual Stress, Microstructure, and Corrosion Resistance of 304 Stainless Steel Welds

    Science.gov (United States)

    Ye, Chang; Telang, Abhishek; Gill, Amrinder; Wen, Xingshuo; Mannava, Seetha R.; Qian, Dong; Vasudevan, Vijay K.

    2018-01-01

    In this study, ultrasonic nanocrystal surface modification (UNSM) of 304 stainless steel welds was carried out. UNSM effectively eliminates the tensile stress generated during welding and imparts beneficial compressive residual stresses. In addition, UNSM can effectively refine the grains and increase hardness in the near-surface region. Corrosion tests in boiling MgCl2 solution demonstrate that UNSM can significantly improve the corrosion resistance due to the compressive residual stresses and changes in the near-surface microstructure.

  13. Creep properties of advanced heat-resistant martensitic steels strengthened by L1{sub 0} type ordered intermetallic phase

    Energy Technology Data Exchange (ETDEWEB)

    Igarashi, M.; Muneki, S.; Abe, F. [National Res. Inst. for Metals, Tsukuba (Japan). Frontier Res. Center for Struct. Mater.

    2000-07-01

    Creep properties of advanced heat-resistant martensitic steels with the compositions of 0.08C-0.3Si-0.5Mn-9Cr-3.3W-(0/3)Pd-0.2V-0.05Nb-0.05N-Fe (in mass%) have been studied to explore the fundamental guiding principles for the development of new steels with improved creep strength at higher temperatures over 650 C. The steel with 3%Pd exhibits higher creep strength than that of the base steel, in particular, at higher temperatures. The microstructure of the steel with Pd is characterized by fine precipitation of a FePd based L1{sub 0} type ordered phase, {alpha}{sup ''} phase. The {alpha}{sup ''} phase forms in the tempered martensitic matrix, {alpha}, along with the existing phases such as MX (M; V, Nb, X; C, N) carbonitride and M{sub 23}C{sub 6} (M; Cr, Fe, W) carbide after normalizing at 1100 C and tempering at 770 C. A detailed TEM observation has shown that the {alpha}{sup ''} phase precipitates in a plate-shaped with the habit plane parallel to {l_brace}001{r_brace}{sub {alpha}} and with a crystallographic orientation relationship with the matrix, {l_brace}001{r_brace}{sub {alpha}}//{l_brace}001{r_brace}{sub {alpha}{sup ''}} and left angle 100 right angle {sub {alpha}}// left angle 110 right angle {sub {alpha}{sup ''}}. The {alpha}{sup ''} phase is found to be a most effective precipitate to increase creep resistance of the steel in terms of the inter-particle spacing estimated. The {alpha}{sup ''} phase is stable even after aging at 700 C and hence is more useful at higher temperatures. It is thus concluded that the creep resistance of the ferritic steels can be increased further by optimizing the combination of fine precipitation such as the {alpha}{sup ''} phase and MX carbonitride. (orig.)

  14. The Microstructure and Pitting Resistance of Weld Joints of 2205 Duplex Stainless Steel

    Science.gov (United States)

    Wu, Mingfang; Liu, Fei; Pu, Juan; Anderson, Neil E.; Li, Leijun; Liu, Dashuang

    2017-11-01

    2205 duplex stainless steel (DSS) was welded by submerged arc welding. The effects of both heat input and groove type on the ferrite/austenite ratio and elemental diffusion of weld joints were investigated. The relationships among welding joint preparation, ferrite/austenite ratio, elemental diffusion, and pitting corrosion resistance of weld joints were analyzed. When the Ni content of the weld wire deposit was at minimum 2-4% higher than that of 2205 DSS base metal, the desired ratio of ferrite/austenite and elemental partitioning between the austenite and ferrite phases were obtained. While the pitting sensitivity of weld metal was higher than that of base metal, the self-healing capability of the passive film of weld metal was better than that of the base metal when a single V-type groove was used. Furthermore, the heat input should be carefully controlled since pitting corrosion occurred readily in the coarse-grained heat-affected zone near the fusion line of welded joints.

  15. Mechanism of selective corrosion in electrical resistance seam welded carbon steel pipe

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Fajardo, Pedro; Godinez Salcedo, Jesus; Gonzalez Velasquez, Jorge L. [Instituto Politecnico Nacional, Mexico D.F., (Mexico). Escuela Superior de Ingenieria Quimica e Industrias Extractivas. Dept. de Ingenieria Metalurgica

    2009-07-01

    In this investigation the studies of the mechanism of selective corrosion in electrical resistance welded (ERW) carbon steel pipe was started. Metallographic characterizations and evaluations for inclusions were performed. The susceptibility of ERW pipe to selective corrosion in sea water (NACE 1D182, with O{sub 2} or CO{sub 2} + H{sub 2}S) was studied by the stepped potential Potentiostatic electrochemical test method in samples of 1 cm{sup 3} (ASTM G5) internal surface of the pipe (metal base-weld). The tests were looking for means for predicting the susceptibility of ERW pipe to selective corrosion, prior to placing the pipeline in service. Manganese sulfide inclusions are observed deformed by the welding process and they are close to the weld centerline. A slight decarburization at the weld line is observed, and a distinct out bent fiber pattern remains despite the post-weld seam annealing. The microstructure of the weld region consists of primarily polygonal ferrite grains mixed with small islands of pearlite. It is possible to observe the differences of sizes of grain of the present phases in the different zones. Finally, scanning electron microscopic observation revealed that the corrosion initiates with the dissolution of MnS inclusions and with small crack between the base metal and ZAC. (author)

  16. Nonlinear Modelling, Design, and Test of Steel Blast-Resistant Doors

    Directory of Open Access Journals (Sweden)

    V. A. Salomoni

    2013-01-01

    Full Text Available The nonlinear dynamic response for steel blast-resistant doors is here described, referring to an innovative experience at both national and international level requiring an ad hoc design and specific numerical simulations. The elements capability to sustain thermal loads due to fire hazards is additionally accounted for. The study has been conducted to define and characterize the nonlinear behaviour of a large number of doors, with the objective of sustaining dynamic loads from explosive hazards of fixed magnitude, as well as variable design and clearing times. The local overcome of the material strength limit (with correspondent plastic response and possible formation of plastic hinges has been critically discussed. Numerical models have allowed for refining first design sketches and subsequently understanding the real thermomechanical behaviour for the investigated elements. Some experimental tests have been additionally performed, verifying the correctness of the already available numerical results, validating the adopted procedures, and correspondingly guaranteeing the doors' structural efficiency even under dynamic loads higher than design ones.

  17. Application of Viscous Dampers in Seismic Rehabilitation of Steel Moment Resisting Frames

    Directory of Open Access Journals (Sweden)

    Saghafi Mohammad Hossein

    2016-01-01

    Full Text Available In structural seismic rehabilitation, the structural capacity spectrum curve can be enhanced by increasing the stiffness and strength of the structures and also the application of the energy dissipation systems such as dampers can decrease the structural demand spectrum curve. Dampers are basically used to mitigate the structural response and decrease the damages to the main structural elements under severe earthquakes through energy dissipation.At the present paper, it is aimed to evaluate the seismic behavior of two conventional steel moment resisting frames having 4, 8 stories incorporating seismic strength imperfection equipped with viscous dampers. OpenSees and nonlinear time-history analysis incorporating seven seismic records have been used to define the frame response. The results revealed that the seismic response of rehabilitated frames has been considerably improved. Where, the maximum roof displacement, the maximum story drift, the maximum floor acceleration and shears have been declined in damper equipped frames and the seismic performance of the most rehabilitated frame elements under an earthquake having return period of 475 years has been upgraded to performance level of life-safety.

  18. Characterizing ground motions that collapse steel special moment-resisting frames or make them unrepairable

    Science.gov (United States)

    Olsen, Anna H.; Heaton, Thomas H.; Hall, John F.

    2015-01-01

    This work applies 64,765 simulated seismic ground motions to four models each of 6- or 20-story, steel special moment-resisting frame buildings. We consider two vector intensity measures and categorize the building response as “collapsed,” “unrepairable,” or “repairable.” We then propose regression models to predict the building responses from the intensity measures. The best models for “collapse” or “unrepairable” use peak ground displacement and velocity as intensity measures, and the best models predicting peak interstory drift ratio, given that the frame model is “repairable,” use spectral acceleration and epsilon (ϵ) as intensity measures. The more flexible frame is always more likely than the stiffer frame to “collapse” or be “unrepairable.” A frame with fracture-prone welds is substantially more susceptible to “collapse” or “unrepairable” damage than the equivalent frame with sound welds. The 20-story frames with fracture-prone welds are more vulnerable to P-delta instability and have a much higher probability of collapse than do any of the 6-story frames.

  19. Influence of stress on creep deformation properties of 9-12Cr ferritic creep resistant steels

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, K.; Sawada, K.; Kushima, H. [National Institute for Materials Science (Japan)

    2008-07-01

    Creep deformation property of 9-12Cr ferritic creep resistant steels was investigated. With decrease in stress, a magnitude of creep strain at the onset of accelerating creep stage decreased from about 2% in the short-term to less than 1% in the longterm. A time to 1% total strain was observed in the transient creep stage in the short term regime, however, it shifted to the accelerating creep stage in the long-term regime. Life fraction of the times to 1% creep strain and 1% total strain tended to increase with decrease in stress. Difference in stress dependence of the minimum creep rate was observed in the high- and low-stress regimes with a boundary condition of 50% of 0.2% offset yield stress. Stress dependence of the minimum creep rate in the high stress regime was equivalent to a strain rate dependence of the flow stress evaluated by tensile test, and a magnitude of stress exponent, n, in the high stress regime decreased with increase in temperature from 20 at 550 C to 10 at 700 C. On the other hand, n value in the low stress regime was about 5, and creep deformation in the low stress regime was considered to be controlled by dislocation climb. Creep rupture life was accurately predicted by a region splitting method by considering a change in stress dependence of creep deformation. (orig.)

  20. Laser gas assisted treatment of steel 309: Corrosion and scratch resistance of treated surface

    Science.gov (United States)

    Toor, Ihsan-ul-Haq; Yilbas, B. S.; Ahmed, Junaid; Karatas, C.

    2017-10-01

    Laser gas assisted surface treatment of steel 309 is carried out and the characteristics of the resulting surface are analyzed using the analytical tools. Scanning electron and 3-D optical microscopes are used to assess the morphological and metallurgical changes in the laser treated layer. Energy spectroscopy and X-ray diffraction are carried out to determine the elemental composition and compounds formed on the laser treated surface. The friction coefficient of the laser treated surface is measured using the micro-tribometer and compared to that of the as received surface. The corrosion resistance of the laser treated and as received surfaces is measured incorporating the electrochemical tests. It is found that laser treatment results in a dense layer and formation of nitride compounds at the surface. This enhances the microhardness at the laser treated surface. The friction coefficient attains lower values at the laser treated surface than that corresponding to the as received surface. The corrosion rate of the surface reduces significantly after the laser treatment process, which can be attributed to the passive layer at the surface via formation of a dense layer and nitride compounds in the surface vicinity. In addition, the number of pit sites decreased for the laser treated surface than that of as received surface.

  1. Corrosion resistance of a steel under an oxidizing atmosphere in a fluid catalytic cracking regenerator

    Directory of Open Access Journals (Sweden)

    Ieda Caminha

    2004-03-01

    Full Text Available In the present work, the corrosion resistance of an ASTM A 387 G11 steel was evaluated under two conditions: an oxidizing atmosphere in a fluid catalytic cracking regenerator of a petroleum processing unit and a simulated atmosphere in the laboratory, at temperatures of 650 °C and 700 °C. The characterization of the phases present in the oxidized layer was carried out by X-ray diffraction (XRD, optical microscopy (OM and scanning electron microscopy (SEM with X-ray energy dispersive analysis (EDS. Severe corrosion was observed after exposure to both the real and simulated conditions, with formation of several iron oxides (Fe2O3, Fe3O4 and FeO in the product scale layer, as well as a slight inner oxidation and sulfidation of chromium in the substrate. Internal nitridation of the silicon and the manganese was observed only in the real condition, probably related to the long-term exposure inside the regenerator.

  2. Resistance spot welding of galvanized steel: Part I. Material variations and process modifications

    Science.gov (United States)

    Gedeon, S. A.; Eagar, T. W.

    1986-12-01

    Material variations and process modifications have been studied to determine their effects on the acceptable range of resistance spot welding conditions for galvanized steel sheet. The material variations studied include zinc coating integrity, structure, composition, thickness, roughness, oil, and the amount and type of Fe-Zn intermetallics. Process modifications studied include upsloping and downsloping of the weld current, preheat current, postheat current, electrode tip geometry, and applied force. It was found that hot-dipped galvanized materials with coatings which have a very thin Fe-Zn alloy layer have a wider range of acceptable welding conditions than the commercial galvannealed products, which have a fully alloyed Fe-Zn coating. The decreased lobe width of the galvannealed material is due to the discontinuous Fe-Zn coating structure and morphology. Small variations in the thickness of the coatings studied have no significant effect on the welding current range. Surface roughness of the coating has no effect on lobe width. Upsloping and downsloping of the weld current increase the welding range of hot-dipped products when using truncated cone electrodes, whereas sloped current has no advantage for galvannealed or uncoated materials. Radiused electrodes can increase the lobe width of hot-dipped products but are not beneficial when using sloped current or when welding galvannealed or uncoated materials.

  3. Pushover Analysis of Steel Seismic Resistant Frames with Reduced Web Section and Reduced Beam Section Connections

    Directory of Open Access Journals (Sweden)

    Daniel Tomas Naughton

    2017-10-01

    Full Text Available The widespread brittle failure of welded beam-to-column connections caused by the 1994 Northridge and 1995 Kobe earthquakes highlighted the need for retrofitting measures effective in reducing the strength demand imposed on connections under cyclic loading. Researchers presented the reduced beam section (RBS as a viable option to create a weak zone away from the connection, aiding the prevention of brittle failure at the connection weld. More recently, an alternative connection known as a reduced web section (RWS has been developed as a potential replacement, and initial studies show ideal performance in terms of rotational capacity and ductility. This study performs a series of non-linear static pushover analyses using a modal load case on three steel moment-resisting frames of 4-, 8-, and 16-storeys. The frames are studied with three different connection arrangements; fully fixed moment connections, RBSs and RWSs, in order to compare the differences in capacity curves, inter-storey drifts, and plastic hinge formation. The seismic-resistant connections have been modeled as non-linear hinges in ETABS, and their behavior has been defined by moment-rotation curves presented in previous recent research studies. The frames are displacement controlled to the maximum displacement anticipated in an earthquake with ground motions having a 2% probability of being exceeded in 50 years. The study concludes that RWSs perform satisfactorily when compared with frames with fully fixed moment connections in terms of providing consistent inter-storey drifts without drastic changes in drift between adjacent storeys in low- to mid-rise frames, without significantly compromising the overall strength capacity of the frames. The use of RWSs in taller frames causes an increase in inter-storey drifts in the lower storeys, as well as causing a large reduction in strength capacity (33%. Frames with RWSs behave comparably to frames with RBSs and are deemed a suitable

  4. Improving corrosion and wear resistance of FV520B steel by high current pulsed electron beam surface treatment

    Energy Technology Data Exchange (ETDEWEB)

    Hao, Shengzhi, E-mail: ebeam@dlut.edu.cn [Key Laboratory of Material Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China); Zhao, Limin [School of Materials Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Zhang, Yanlong; Wang, Huihui [Key Laboratory of Material Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116024 (China)

    2015-08-01

    Highlights: • HCPEB surface treatment was conducted on FV520B steel. • Surface layer ∼10 μm was refined with elements homogenization. • Remelted layer exhibited 〈2 0 0〉 preferential orientation. • Corrosion potential increased and corrosion rate decreased one order of magnitude. • Wear resistance increased by 3 times. - Abstract: High current pulsed electron beam (HCPEB) surface treatment was conducted on FV520B steel with accelerating voltage 27 kV, pulse duration 2.5 μs, energy density 5 J/cm{sup 2} and 1–25 pulses. The surface microstructure and element distribution were examined by using scanning electron microscope (SEM), electron probe micro-analysis (EPMA) and X-ray diffraction (XRD) methods. After HCPEB treatments, the surface microstructure became refined and uniform with an average grain size less than 2 μm and a preferential solidification orientation in 〈2 0 0〉 direction. The thickness of surface remelted layer was ∼4 μm. The initial precipitated particles in surface layer of depth ∼10 μm were dissolved into the base matrix and gave a homogenous element distribution. The HCPEB modified surface exhibited an effective improvement in corrosion and wear resistance. The corrosion potential shifted towards positive and the corrosion rate decreased nearly one order of magnitude, while the wear resistance after 25 pulses of HCPEB treatment increased by 3 times as compared with the initial FV520B steel.

  5. Improvement of erosion and erosion corrosion resistance of AISI420 stainless steel by low temperature plasma nitriding

    Science.gov (United States)

    Xi, Yun-tao; Liu, Dao-xin; Han, Dong

    2008-07-01

    Plasma nitriding experiments were carried out with DC-pulsed plasma in 25% N 2 + 75% H 2 atmosphere at low temperature (350 °C) and normal temperature (550 °C) for 15 h. The composition, microstructure, microhardness profiles, residual stress profiles and electrochemical impedance spectrum analyses of the nitrided samples were examined. The influence of plasma nitriding on the erosion and erosion-corrosion resistance of AISI 420 martensitic stainless steel was investigated using a jet solid particle erosion tester and a slurry erosion-corrosion tester. Results showed that the 350 °C nitriding layer was dominated by ɛ-Fe 3N and α N phase, a supersaturated nitrogen solid solution. However, nitrogen would react with Cr in the steel to form CrN precipitates directly during 550 °C nitriding, which would lead to the depletion of Cr in the solid solution phase of the nitrided layer. Both 350 and 550 °C plasma nitriding could improve the erosion resistance of AISI420 stainless steel under dry erosion, but the former showed better results. In both neutral and acid environment, while the erosion-corrosion resistance of AISI 420 was improved by means of 350 °C nitriding, it was decreased through 550 °C nitriding.

  6. Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062

    Science.gov (United States)

    Rosemann, P.; Müller, C.; Baumann, O.; Modersohn, W.; Halle, T.

    2017-03-01

    The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polished or blasting depending on the application and the requested corrosion resistance. Blasted surfaces are often used in industrial practice due to the easier and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the different performed corrosion tests (potential measurement, KorroPad-test and pitting potential) on welding seams with different surface treatments.

  7. Effect of Explosion Bulge Test Parameters on the Measurement of Deformation Resistance for Steel

    Science.gov (United States)

    2014-02-01

    solidification cracking in steels and stainless steels. He has also undertaken extensive work on improving the weld zone toughness of high strength steels...plate rolling direction (Figure 1). These weld beads are composed of hard facing material that is inherently brittle and, under blast loading, act as a...connected to a NI 9213 Module with 16 channels and 24 Bit thermocouple inputs from National Instruments ( NI ). The NI module was then connected to the NI

  8. Composite structure of steel and shape memory alloy for fire resistance design

    OpenAIRE

    Fang, Han

    2017-01-01

    Steel is one of the most widely used construction materials in buildings which may be subject to fire. In fire, the strength of steel drops significantly with increasing temperature and structural failures may occur. In this research study, an innovative approach to strengthen the steel beams in fire using shape memory alloys (SMAs) was investigated. The prestrained SMAs have the unique ability to generate large recovery stress with increasing temperatures which can be taken advantage of to ...

  9. Nitrate treatment effects on bacterial community biofilm formed on carbon steel in produced water stirred tank bioreactor.

    Science.gov (United States)

    Marques, Joana Montezano; de Almeida, Fernando Pereira; Lins, Ulysses; Seldin, Lucy; Korenblum, Elisa

    2012-06-01

    To better understand the impact of nitrate in Brazilian oil reservoirs under souring processes and corrosion, the goal of this study was to analyse the effect of nitrate on bacterial biofilms formed on carbon steel coupons using reactors containing produced water from a Brazilian oil platform. Three independent experiments were carried out (E1, E2 and E3) using the same experimental conditions and different incubation times (5, 45 and 80 days, respectively). In every experiment, two biofilm-reactors were operated: one was treated with continuous nitrate flow (N reactor), and the other was a control reactor without nitrate (C reactor). A Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis approach using the 16S rRNA gene was performed to compare the bacterial groups involved in biofilm formation in the N and C reactors. DGGE profiles showed remarkable changes in community structure only in experiments E2 and E3. Five bands extracted from the gel that represented the predominant bacterial groups were identified as Bacillus aquimaris, B. licheniformis, Marinobacter sp., Stenotrophomonas maltophilia and Thioclava sp. A reduction in the sulfate-reducing bacteria (SRB) most probable number counts was observed only during the longer nitrate treatment (E3). Carbon steel coupons used for biofilm formation had a slightly higher weight loss in N reactors in all experiments. When the coupon surfaces were analysed by scanning electron microscopy, an increase in corrosion was observed in the N reactors compared with the C reactors. In conclusion, nitrate reduced the viable SRB counts. Nevertheless, the nitrate dosing increased the pitting of coupons.

  10. Study on surface topography of 446M stainless steel as a bipolar plate on interfacial contact resistance of polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Kim, Kwang Min; Kim, Seok Nyeon; Kim, Jong Hee; Lee, Yun Yong; Kim, Kyoo Young

    2012-12-01

    The effect of the surface topography of 446M ferritic stainless steel as a bipolar plate for polymer electrolyte membrane fuel cell (PEMFC) is evaluated by interfacial contact resistance (ICR) measurement and finite element method (FEM) simulation. When the surface of stainless steel is in contact with the carbon paper under load, the surface roughness of stainless steel can affect the degree of deformation of the carbon fiber. Moreover, the higher deformation of carbon fiber under load in the rougher stainless steel could lead to larger real contact area between stainless steel and carbon fiber, and consequently the rough one has a lower ICR value than the fine one. The results suggest that the topography of stainless steel as a bipolar plate significantly affects the ICR. Furthermore, it was found that topography of bipolar plate is one of the key factors to decrease ICR.

  11. AISI/DOE Technology Roadmap Program: Development of Appropriate Resistance Spot Welding Practice for Transformation-Hardened Steels

    Energy Technology Data Exchange (ETDEWEB)

    Wayne Chuko; Jerry Gould

    2002-07-08

    This report describes work accomplished in the project, titled ''Development of Appropriate Resistance Spot Welding Practice for Transformation-Hardened Steels.'' The Phase 1 of the program involved development of in-situ temper diagrams for two gauges of representative dual-phase and martensitic grades of steels. The results showed that tempering is an effective way of reducing hold-time sensitivity (HTS) in hardenable high-strength sheet steels. In Phase 2, post-weld cooling rate techniques, incorporating tempering, were evaluated to reduce HTS for the same four steels. Three alternative methods, viz., post-heating, downsloping, and spike tempering, for HTS reduction were investigated. Downsloping was selected for detailed additional study, as it appeared to be the most promising of the cooling rate control methods. The downsloping maps for each of the candidate steels were used to locate the conditions necessary for the peak response. Three specific downslope conditions (at a fix ed final current for each material, timed for a zero-, medium-, and full-softening response) were chosen for further metallurgical and mechanical testing. Representative samples, were inspected metallographically, examining both local hardness variations and microstructures. The resulting downslope diagrams were found to consist largely of a C-curve. The softening observed in these curves, however, was not supported by subsequent metallography, which showed that all welds made, regardless of material and downslope condition, were essentially martensitic. CCT/TTT diagrams, generated based on microstructural modeling done at Oak Ridge National Laboratories, showed that minimum downslope times of 2 and 10 s for the martensitic and dual-phase grades of steels, respectively, were required to avoid martensite formation. These times, however, were beyond those examined in this study. These results show that downsloping is not an effective means of reducing HTS for

  12. Finishes for Metals. Paintability of Galvanized Steel, Corrosion Resistance of Metallized Coatings.

    Science.gov (United States)

    Building Research Inst., Inc., Washington, DC.

    Two papers are presented. The first, "Report of the AISI Research Project on the Paintability of Galvanized Steel," was a project aimed at determining optimum procedures for painting bright-spangled galvanized sheet steel products using three classes of trade sales paints--metallic zinc-dust, portland cement-in-oil, and water base emulsion paints.…

  13. Corrosion resistance of steel fibre reinforced concrete – a literature review

    DEFF Research Database (Denmark)

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders

    2016-01-01

    literature concerning chloride-induced corrosion on steel fibres, as well as the impact of steel fibre corrosion on the residual-tensile strength of SFRC. The review confirms the agreement among academics and regulators regarding the superior durability of un-cracked SFRC exposed to chlorides, relative...

  14. Electrochemical methods for characterisation of thermal spray corrosion resistant stainless steel coatings

    NARCIS (Netherlands)

    Hofman, R.; Vreijling, M.P.W.; Ferrari, G.M.; Wit, J.H.W. de

    1998-01-01

    The use of thermal spray stainless steel coatings for protection of low alloyed steels against different types of corrosion is limited due to high porosity levels and oxide inclusions. In this paper electrochemical methods like corrosion potential monitoring and cyclic voltammetry are reported to

  15. Stainless steel in contact with food and bevarage

    Directory of Open Access Journals (Sweden)

    Sveto Cvetkovski

    2012-12-01

    Full Text Available Stainless steels are probably the most important materials in the food and beverage industries. The main reason for such broad implementation of stainless steel in contact with food are excellent properties which they possess such as corrosion resistance, resistance to high and low temperatures, very good mechanical and physical properties, aesthetic appeal, inertness of surface, durability, easy cleaning and recycling. Low thermal conductivity of these steels produces steeper temperature coefficient provoking an increased distortion, shrinkage and stresses compared with carbon steel.

  16. Heat Transfer Modeling of an Annular On-Line Spray Water Cooling Process for Electric-Resistance-Welded Steel Pipe.

    Science.gov (United States)

    Chen, Zejun; Han, Huiquan; Ren, Wei; Huang, Guangjie

    2015-01-01

    On-line spray water cooling (OSWC) of electric-resistance-welded (ERW) steel pipes can replace the conventional off-line heat treatment process and become an important and critical procedure. The OSWC process improves production efficiency, decreases costs, and enhances the mechanical properties of ERW steel pipe, especially the impact properties of the weld joint. In this paper, an annular OSWC process is investigated based on an experimental simulation platform that can obtain precise real-time measurements of the temperature of the pipe, the water pressure and flux, etc. The effects of the modes of annular spray water cooling and related cooling parameters on the mechanical properties of the pipe are investigated. The temperature evolutions of the inner and outer walls of the pipe are measured during the spray water cooling process, and the uniformity of mechanical properties along the circumferential and longitudinal directions is investigated. A heat transfer coefficient model of spray water cooling is developed based on measured temperature data in conjunction with simulation using the finite element method. Industrial tests prove the validity of the heat transfer model of a steel pipe undergoing spray water cooling. The research results can provide a basis for the industrial application of the OSWC process in the production of ERW steel pipes.

  17. Electrochemical study on the corrosion resistance of plasma nanocoated 316L stainless steel in albumin- and lysozyme-containing electrolytes

    Science.gov (United States)

    Jones, John Eric; Chen, Meng; Chou, Ju; Yu, Qingsong

    2017-01-01

    The physiological corrosion resistance of plasma nanocoated 316L stainless steel was studied in protein-containing electrolytes using electrochemical methods. Plasma nanocoatings with thicknesses of 20–30 nm were deposited onto 316L stainless steel coupons in a glow discharge of trimethylsilane (TMS) or its mixture with oxygen gas under various gas ratios. The surface chemistries of the plasma nanocoatings were characterized using Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). Corrosion properties of the plasma nanocoated 316L stainless steel coupons were assessed using potentiodynamic polarization, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) in phosphate-buffered saline (PBS) electrolytes that contain bovine serum albumin (BSA) or lysozyme. It was found that BSA adsorption on the plasma nanocoated 316L coupons was heavily favored. BSA adsorption on the plasma nanocoating surfaces could block charge-transfer reactions between the electrolyte and 316L substrate, and thus stabilize the 316L substrates from further corrosion. In contrast, lysozyme adsorption on the plasma nanocoated specimens was not as pronounced and mildly influenced the corrosion properties of the plasma nanocoated 316L stainless steel.

  18. TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method

    OpenAIRE

    Rozmus-Górnikowska M.; Blicharski M.

    2017-01-01

    The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT) method. Investigations were primarily carried out through transmission electron microscopy (TEM) on thin foils prepared by FIB (Focus Ion Beam).

  19. TEM Microstructure and Chemical Composition of Transition Zone Between Steel Tube and An Inconel 625 Weld Overlay Coating Produced by CMT Method

    Directory of Open Access Journals (Sweden)

    Rozmus-Górnikowska M.

    2017-06-01

    Full Text Available The aim of this work was to investigate the microstructure and chemical composition of the transition zone between 16Mo3 steel and Inconel 625 weld overlay coating produced by the Cold Metal Transfer (CMT method. Investigations were primarily carried out through transmission electron microscopy (TEM on thin foils prepared by FIB (Focus Ion Beam.

  20. Extremely durable biofouling-resistant metallic surfaces based on electrodeposited nanoporous tungstite films on steel

    Science.gov (United States)

    Tesler, Alexander B.; Kim, Philseok; Kolle, Stefan; Howell, Caitlin; Ahanotu, Onye; Aizenberg, Joanna

    2015-01-01

    Formation of unwanted deposits on steels during their interaction with liquids is an inherent problem that often leads to corrosion, biofouling and results in reduction in durability and function. Here we report a new route to form anti-fouling steel surfaces by electrodeposition of nanoporous tungsten oxide (TO) films. TO-modified steels are as mechanically durable as bare steel and highly tolerant to compressive and tensile stresses due to chemical bonding to the substrate and island-like morphology. When inherently superhydrophilic TO coatings are converted to superhydrophobic, they remain non-wetting even after impingement with yttria-stabilized-zirconia particles, or exposure to ultraviolet light and extreme temperatures. Upon lubrication, these surfaces display omniphobicity against highly contaminating media retaining hitherto unseen mechanical durability. To illustrate the applicability of such a durable coating in biofouling conditions, we modified naval construction steels and surgical instruments and demonstrated significantly reduced marine algal film adhesion, Escherichia coli attachment and blood staining. PMID:26482559

  1. Resistance Upset Welding of ODS Steel Fuel Claddings—Evaluation of a Process Parameter Range Based on Metallurgical Observations

    Directory of Open Access Journals (Sweden)

    Fabien Corpace

    2017-08-01

    Full Text Available Resistance upset welding is successfully applied to Oxide Dispersion Strengthened (ODS steel fuel cladding. Due to the strong correlation between the mechanical properties and the microstructure of the ODS steel, this study focuses on the consequences of the welding process on the metallurgical state of the PM2000 ODS steel. A range of process parameters is identified to achieve operative welding. Characterizations of the microstructure are correlated to measurements recorded during the welding process. The thinness of the clad is responsible for a thermal unbalance, leading to a higher temperature reached. Its deformation is important and may lead to a lack of joining between the faying surfaces located on the outer part of the join which can be avoided by increasing the dissipated energy or by limiting the clad stick-out. The deformation and the temperature reached trigger a recrystallization phenomenon in the welded area, usually combined with a modification of the yttrium dispersion, i.e., oxide dispersion, which can damage the long-life resistance of the fuel cladding. The process parameters are optimized to limit the deformation of the clad, preventing the compactness defect and the modification of the nanoscale oxide dispersion.

  2. Effect of electromagnetic interaction during fusion welding of AISI 2205 duplex stainless steel on the corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: marcogarciarenteria@uadec.edu.mx [Faculty of Metallurgy, Autonomous University of Coahuila, Carretera 57 Km. 5, CP 25720, Monclova, Coahuila (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); 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); 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: franciscocl7@yahoo.com.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); Curiel-López, F.F., E-mail: franciscocl7@yahoo.com.mx [Faculty of Metallurgy, Autonomous University of Coahuila, Carretera 57 Km. 5, CP 25720, Monclova, Coahuila (Mexico)

    2017-02-28

    Highlights: • Application of EMILI during welding 2205 Duplex stainless steel hindered the coarsening of δ grains in HTHAZ and promoted regeneration of γ. • Welds made with simultaneous EMILI presented TPI values at the HTHAZ similar to those for BM. • Welds made under 3, 12 and 15 mT presented a mass loss by anodic polarisation similar to that observed for the as-received BM. • This behaviour is due to changes in the dynamics of microstructural evolution during welding with EMILI. - Abstract: 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.

  3. Effect of Impurity Tin on the Creep Properties of a P91 Heat-Resistant Steel

    Science.gov (United States)

    Song, S.-H.; Xu, Y.-W.; Yang, H.-F.

    2014-09-01

    The creep properties of P91 steel specimens undoped and doped with 0.058 wt pct tin, which was normalized from 1328 K (1055 °C) and tempered at 1033 K (760 °C), were examined under different engineering stresses (150 to 210 MPa) and temperatures [873 K to 923 K (600 °C to 650 °C)]. The creep behavior followed the temperature-compensated power law and Monkman-Grant equations. In the temperature-compensated power law equation, the apparent activation energy and stress exponent for creep were approximately 541 kJ/mol and 12 for the undoped steel and 527 kJ/mol and 11 for the Sn-doped one, respectively. In the Monkman-Grant relation, the values of constants m and C were around 1.062 and 0.0672 for the undoped steel, and 1.012 and 0.0650 for the Sn-doped one, respectively. The 100 MPa stress creep lifetime at 873 K (600 °C) was estimated as 100641 hours for the undoped steel and 35290 hours for the Sn-doped steel, respectively. These indicated that Sn substantially deteriorated the creep properties of the steel. It was found that grain or subgrain boundary segregation of Sn could promote the nucleation of cavities or microcracks, thereby leading to the deterioration of the steel creep properties.

  4. Creep strength and microstructural evolution of 9-12% Cr heat resistant steels during creep exposure at 600 C and 650 C

    Energy Technology Data Exchange (ETDEWEB)

    Mendez Martin, Francisca [Graz Univ. of Technology (Austria). Inst. for Materials Science and Welding; Panait, Clara Gabriela [MINES ParisTech, UMR CNRS, Evry (France). Centre des Materiaux; V et M France CEV, Aulnoye-Aymeries (France); Bendick, Walter [Salzgitter Mannesmann Forschung GmbH (SZMF), Duisburg (DE)] (and others)

    2010-07-01

    9-12% Cr heat resistant steels are used for applications at high temperatures and pressures in steam power plants. 12% Cr steels show higher creep strength and higher corrosion resistance compared to 9% Cr steels for short term creep exposure. However, the higher creep strength of 12 %Cr steels drops increasingly after 10,000-20,000 h of creep. This is probably due to a microstructural instability such as the precipitation of new phases (e.g. Laves phases and Z-phases), the growth of the precipitates and the recovery of the matrix. 9% Cr and 12% Cr tempered martensitic steels that have been creep tested for times up to 50,000 h at 600 C and 650 C were investigated using Transmission Electron Microscopy (TEM) on extractive replicas and thin foils together with Backscatter Scanning Electron Microscopy (BSE-SEM) to better understand the different creep behaviour of the two different steels. A significant precipitation of Laves phase and low amounts of Z-phase was observed in the 9% Cr steels after long-term creep exposure. The size distribution of Laves phases was measured by image analysis of SEM-BSE images. In the 12% Cr steel two new phases were identified, Laves phase and Z-phase after almost 30,000 h of creep test. The quantification of the different precipitated phases was studied. (orig.)

  5. Selection of 5-fluorocytosine-resistant mutants from an Aspergillus niger citric acid-producing strain

    Directory of Open Access Journals (Sweden)

    Conte Ana Paula de F.

    2003-01-01

    Full Text Available Mutants of Aspergillus niger N402, induced by UV mutagenesis, were selected and tested for resistance or sensitivity to 5-fluorocytosine. Some mutants showed increased citric acid production, which did not correlate with the intracellular amount of protein or ammonium ion. The resistance to 5-fluorocytosine proved to be a rational approach for isolation of new mutants with improved production of citric acid. The best mutant (FR13 accumulated double the amount of citric acid produced by the parental strain.

  6. Evolution of microstructure of the new heat resistant 9 - 11 % Cr steels as a function of long term creep stressing

    Energy Technology Data Exchange (ETDEWEB)

    Kauffmann, F. [Stuttgart Univ. (Germany). MPA; Kern, T.U. [Siemens AG, Muehlheim (Germany). Energy Sector; Straub, S. [ALSTOM Power Systems GmbH, Mannheim (Germany); Mayer, K.H. [ALSTOM Power Systems GmbH, Nuernberg (Germany)

    2010-07-01

    The development of new creep resistant materials for higher temperatures in the field of energy generation is a key topic with high technological, economical and environmental interest. The strength and usability of typical materials in this area are 9 - 11 % Cr steels additional alloyed with Mo, W, V, Nb, N and B, which are governed by their microstructural features such as precipitations in the sub-micron range, the dislocation density, the subgrain sizes and in unfavorable cases with the formation of boride-particles. The evaluation of these features and the understanding of their correlation with the long-time creep properties is of pivotal interest in the development of improved materials. This paper will focus on two aspects: the correlation of the microstructure after long testing times with the corresponding creep properties and the measurement and possible quantification of borides in these steels. (orig.)

  7. Experimental Studies on Punching Shear and Impact Resistance of Steel Fibre Reinforced Slag Based Geopolymer Concrete

    OpenAIRE

    Karunanithi, Srinivasan

    2017-01-01

    The study was focused on slag based geopolymer concrete with the addition of steel fibre. The slag based geopolymer concrete was under shear load and sudden impact load to determine its response. The punching shear represents the load dissipation of the material and the energy absorption capacity of the geopolymer concrete to impact load. The various percentage of steel fibre in the slag based geopolymer concrete was 0.5%, 1.0%, and 1.5%. Overall the dosage 0.5% of steel fibre reinforced slag...

  8. Tribological resistance of high speed steel HS 6-5-2 remelted with electric arc

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2009-07-01

    Full Text Available The intensity of tribological wear of the high speed steel HS 6-5-2 remelted with the GTAW method has been compared to the heat treatment steel in a conventional way. Moreover, the types of the wear appeared during the friction. The tribiological research, were done in the technically dry friction conditions on a testing machine of the pin-on-disc T-01M. The smallest intensity of wear was shown by the high speed steel remelted with the parameters leading to obtain the biggest speed of cooling of the molten metal. The main wear type appearing during the research, was the abrasion and adhesive wear.

  9. Bacteriocins produced by L. fermentum and L .acidophilus can inhibit cephalosporin resistant E .coli.

    Directory of Open Access Journals (Sweden)

    Saba Riaz

    2010-10-01

    Full Text Available Reemerging infections occur due to resistant bacteria. Such infections create restrictions for clinicians and microbiologists in drug selection. Such problems demand new strategies for solution. Use of bacteriocins for this purpose may be fruitful. In the present research work, the inhibitory effects of bactericins on cephalosporin resistant Escherichia coli are used as model system for the control of antibiotic resistant pathogenic bacteria. Cephalosporin resistant Escherichia coli strain was isolated from pus by using conventional methodology. For bacteriocin production, Lactobacilli strains were selected by using selective media. Out of seventy two strains isolated from yogurt, fecal materials of human, chick, parrot and cat, only two strains (strain 45 and strain 52 were found to produce bacteriocins having antimicrobial potential against cephalosporin resistant Escherichia coli. Biochemical characterization showed that strain 45 belonged to group of Lactobacillus fermentum and strain 52 to Lactobacillus acidophilus. Both strains showed maximum growth at 25°C and 35°C respectively. Suitable pH was 5.5 and 6.0 for Lactobacillus fermentum and Lactobacillus acidophilus respectively. Bacteriocins produced by both strains were found stable at 50, 75 and 100°C for 60min. Function of bacteriocin was also not disturbed due to change in pH. These findings suggest that bacteriocin produced by Lactobacillus fermentum and Lactobacillus acidophilus can be used for the infection control of cephalosporin resistant Escherichia coli.

  10. Reduced platelet adhesion and improved corrosion resistance of superhydrophobic TiO₂-nanotube-coated 316L stainless steel.

    Science.gov (United States)

    Huang, Qiaoling; Yang, Yun; Hu, Ronggang; Lin, Changjian; Sun, Lan; Vogler, Erwin A

    2015-01-01

    Superhydrophilic and superhydrophobic TiO2 nanotube (TNT) arrays were fabricated on 316L stainless steel (SS) to improve corrosion resistance and hemocompatibility of SS. Vertically-aligned superhydrophilic amorphous TNTs were fabricated on SS by electrochemical anodization of Ti films deposited on SS. Calcination was carried out to induce anatase phase (superhydrophilic), and fluorosilanization was used to convert superhydrophilicity to superhydrophobicity. The morphology, structure and surface wettability of the samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and contact angle goniometry. The effects of surface wettability on corrosion resistance and platelet adhesion were investigated. The results showed that crystalline phase (anatase vs. amorphous) and wettability strongly affected corrosion resistance and platelet adhesion. The superhydrophilic amorphous TNTs failed to protect SS from corrosion whereas superhydrophobic amorphous TNTs slightly improved corrosion resistance of SS. Both superhydrophilic and superhydrophobic anatase TNTs significantly improved corrosion resistance of SS. The superhydrophilic amorphous TNTs minimized platelet adhesion and activation whereas superhydrophilic anatase TNTs activated the formation of fibrin network. On the contrary, both superhydrophobic TNTs (superhydrophobic amorphous TNTs and superhydrophobic anatase TNTs) reduced platelet adhesion significantly and improved corrosion resistance regardless of crystalline phase. Superhydrophobic anatase TNTs coating on SS surface offers the opportunity for the application of SS as a promising permanent biomaterial in blood contacting biomedical devices, where both reducing platelets adhesion/activation and improving corrosion resistance can be effectively combined. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Experimental Studies on Punching Shear and Impact Resistance of Steel Fibre Reinforced Slag Based Geopolymer Concrete

    Directory of Open Access Journals (Sweden)

    Srinivasan Karunanithi

    2017-01-01

    Full Text Available The study was focused on slag based geopolymer concrete with the addition of steel fibre. The slag based geopolymer concrete was under shear load and sudden impact load to determine its response. The punching shear represents the load dissipation of the material and the energy absorption capacity of the geopolymer concrete to impact load. The various percentage of steel fibre in the slag based geopolymer concrete was 0.5%, 1.0%, and 1.5%. Overall the dosage 0.5% of steel fibre reinforced slag based geopolymer shows better results with a punching shear of 224 kN and 1.0% of steel fibre incorporated geopolymer concrete had the better energy absorption capacity with 3774.40 N·m for first crack toughness and 4123.88 N·m for ultimate failure toughness.

  12. Pullout resistance of mechanically stabilized earth wall steel strip reinforcement in uniform aggregate.

    Science.gov (United States)

    2015-11-01

    A wide range of reinforcement-backfill combinations have been used in mechanically stabilized earth (MSE) walls. Steel : strips are one type of reinforcement used to stabilize aggregate backfill through anchorage. In the current MSE wall design, pull...

  13. Corrosion resistance of steel fibre reinforced concrete – a literature review

    OpenAIRE

    Marcos Meson, Victor; Michel, Alexander; Solgaard, Anders; Fischer, Gregor; Edvardsen, Carola; Skovhus, Torben Lund

    2016-01-01

    Steel fibre reinforced concrete (SFRC) is increasingly being used in the construction of prefabricated segmental linings for bored tunnels, since it entails simplified production processes and higher quality standards. However, international standards and guidelines are not consistent regarding the consideration of steel fibres for the structural verification of SFRC elements exposed to corrosive environments, hampering the development of civil infrastructure built of SFRC. In particular, the...

  14. Clean steels for steam turbine rotors—their stress corrosion cracking resistance

    Science.gov (United States)

    Magdowski, Ruth M.; Speidel, Markus O.

    1988-06-01

    This work presents the results of a comprehensive study concerning stress corrosion crack growth rates in steam turbine rotor steels exposed to hot water. The effects of stress intensity, temperature, and dissolved gases in the water have been investigated. Special attention has been given to the influence of impurities and alloying elements in the steel such as P, S, Mn, Si, Mo, and Ni, and to the effect of yield strength and fracture toughness on the growth rates of stress corrosion cracks. The results of this study clearly show that there exists a threshold stress intensity of about 20 MNm-3/2 above which the invariably intergranular stress corrosion cracks grow at a constant, stress-independent velocity. This plateau stress corrosion crack growth rate is not affected by the oxygen and carbon dioxide concentration in the water. The temperature and the yield strength of the steel have a strong influence on the growth rate of stress corrosion cracks. In contrast, there is no effect of the steel composition within the range investigated, neither of the impurity elements such as P and S, nor of the major alloying elements such as Mn, Si, Mo, and Ni. Steels with low fracture toughness due to temper embrittlement do not exhibit faster stress corrosion crack growth rates in water than nonembrittled steels. No direct relationship between intergranular temper embrittlement and intergranular stress corrosion crack growth in water can be demonstrated.

  15. Tool steels

    DEFF Research Database (Denmark)

    Højerslev, C.

    2001-01-01

    On designing a tool steel, its composition and heat treatment parameters are chosen to provide a hardened and tempered martensitic matrix in which carbides are evenly distributed. In this condition the matrix has an optimum combination of hardness andtoughness, the primary carbides provide...... resistance against abrasive wear and secondary carbides (if any) increase the resistance against plastic deformation. Tool steels are alloyed with carbide forming elements (Typically: vanadium, tungsten, molybdenumand chromium) furthermore some steel types contains cobalt. Addition of alloying elements...... serves primarily two purpose (i) to improve the hardenabillity and (ii) to provide harder and thermally more stable carbides than cementite. Assuming proper heattreatment, the properties of a tool steel depends on the which alloying elements are added and their respective concentrations....

  16. Microstructures and High-Temperature Mechanical Properties of a Martensitic Heat-Resistant Stainless Steel 403Nb Processed by Thermo-Mechanical Treatment

    Science.gov (United States)

    Chen, Liqing; Zeng, Zhouyu; Zhao, Yang; Zhu, Fuxian; Liu, Xianghua

    2013-11-01

    Thermo-mechanical treatments (TMT) at different rolling deformation temperatures were utilized to process a martensitic heat-resistant stainless steel 403Nb containing 12 wt pct Cr and small additions of Nb and V. Microstructures and mechanical properties at room and elevated temperatures were characterized by scanning electron microscopy, transmission electron microscopy, and hardness, tensile, and creep tests. The results showed that high-temperature mechanical behavior after TMT can be greatly improved and microstructures with refined martensitic lath and finely dispersed nanosized MX carbides could be produced. The particle sizes of M23C6 and MX carbides in 403Nb steel after conventional normalizing and tempering (NT) treatments are about 50 to 160 and 10 to 20 nm, respectively, while those after TMT at 1123 K (850 °C) and subsequent tempering at 923 K (650 °C) for 2 hours reach about 25 to 85 and 5 to 10 nm, respectively. Under the condition of 260 MPa and 873 K (600 °C), the tensile creep rupture life of 403Nb steel after TMT at 1123 K (850 °C) is 455 hours, more than 3 times that after conventional NT processes. The mechanisms for improving mechanical properties at elevated temperature were analyzed in association with the existence of finely dispersed nanosized MX particles within martensitic lath. It is the nanosized MX particles having the higher stability at elevated temperature that assist both dislocation hardening and sub-grain hardening for longer duration by pinning the movement of dislocations and sub-grain boundary migration.

  17. An experimental study on fracture toughness of resistance spot welded galvanized and ungalvanized DP 450 steel sheets used in automotive body

    Energy Technology Data Exchange (ETDEWEB)

    Sevim, I.

    2016-07-01

    The purpose of this study is to determine fracture toughness of Resistance Spot Welded (RSW) Dual Phase (DP) steels. RSW of galvanized and ungalvanized DP 450 steel sheets was carried out on spot welding machine. Fracture toughness of RSW joints of galvanized and ungalvanized DP 450 steel sheets was calculated from tensile-shear tests. New empirical equations were developed using Least Squares Method (LSM) between energy release rate, fracture toughness and critical crack size depending on the relationship between hardness and fracture toughness values. Results indicated that fracture toughness of joints welded by using RSW increased exponentially while the hardness decreased. In addition, fracture toughness and energy release rate of RSW galvanized DP 450 steel sheets were lower compared to RSW ungalvanized DP 450 steel sheets which had approximately the same hardness. (Author)

  18. Influence of mill scale and rust layer on the corrosion resistance of low-alloy steel in simulated concrete pore solution

    Science.gov (United States)

    Shi, Jin-jie; Ming, Jing

    2017-01-01

    Electrochemical impedance spectroscopy, cyclic potentiodynamic polarization measurements, and scanning electron microscopy in conjunction with energy-dispersive X-ray spectroscopy were used to investigate the influence of mill scale and rust layer on the passivation capability and chloride-induced corrosion behaviors of conventional low-carbon (LC) steel and low-alloy (LA) steel in simulated concrete pore solution. The results show that mill scale exerts different influences on the corrosion resistance of both steels at various electrochemical stages. We propose that the high long-term corrosion resistance of LA steel is mainly achieved through the synergistic effect of a gradually formed compact, adherent and well-distributed Cr-enriched inner rust layer and the physical barrier protection effect of mill scale.

  19. Strategy for Manipulation of Cheese Flora Using Combinations of Lacticin 3147-Producing and -Resistant Cultures

    Science.gov (United States)

    Ryan, Máire P.; Ross, R. Paul; Hill, Colin

    2001-01-01

    The aim of the present study was to develop adjunct strains which can grow in the presence of bacteriocin produced by lacticin 3147-producing starters in fermented products such as cheese. A Lactobacillus paracasei subsp. paracasei strain (DPC5336) was isolated from a well-flavored, commercial cheddar cheese and exposed to increasing concentrations (up to 4,100 arbitrary units [AU]/ml) of lantibiotic lacticin 3147. This approach generated a stable, more-resistant variant of the isolate (DPC5337), which was 32 times less sensitive to lacticin 3147 than DPC5336. The performance of DPC5336 was compared to that of DPC5337 as adjunct cultures in two separate trials using either Lactococcus lactis DPC3147 (a natural producer) or L. lactis DPC4275 (a lacticin 3147-producing transconjugant) as the starter. These lacticin 3147-producing starters were previously shown to control adventitious nonstarter lactic acid bacteria in cheddar cheese. Lacticin 3147 was produced and remained stable during ripening, with levels of either 1,280 or 640 AU/g detected after 6 months of ripening. The more-resistant adjunct culture survived and grew in the presence of the bacteriocin in each trial, reaching levels of 107 CFU/g during ripening, in contrast to the sensitive strain, which was present at levels 100- to 1,000-fold lower. Furthermore, randomly amplified polymorphic DNA-PCR was employed to demonstrate that the resistant adjunct strain comprised the dominant microflora in the test cheeses during ripening. PMID:11375183

  20. Microstructure and Microsegregation of an Inconel 625 Weld Overlay Produced on Steel Pipes by the Cold Metal Transfer Technique

    National Research Council Canada - National Science Library

    M. Rozmus-Górnikowska; Ł. Cieniek; M. Blicharski; J. Kusiński

    2014-01-01

    The aim of this work was to investigate the development of microstructure and variations in chemical composition in commercial Inconel 625 coatings on a ferritic-pearlitic steel overlaid by the CMT method...

  1. Microstructure and Microsegregation of an Inconel 625 Weld Overlay Produced on Steel Pipes by the Cold Metal Transfer Technique

    OpenAIRE

    Rozmus-Górnikowska M.; Cieniek Ł.; Blicharski M.; Kusiński J.

    2014-01-01

    The aim of this work was to investigate the development of microstructure and variations in chemical composition in commercial Inconel 625 coatings on a ferritic-pearlitic steel overlaid by the CMT method.

  2. Microstructure and Microsegregation of an Inconel 625 Weld Overlay Produced on Steel Pipes by the Cold Metal Transfer Technique

    Directory of Open Access Journals (Sweden)

    Rozmus-Górnikowska M.

    2014-10-01

    Full Text Available The aim of this work was to investigate the development of microstructure and variations in chemical composition in commercial Inconel 625 coatings on a ferritic-pearlitic steel overlaid by the CMT method.

  3. Study Regarding the Good Cavitation Erosion Resistance of a 13Cr-4Ni Stainless Steel used to Manufacture the Components Exposed to Water of the Hydraulic Turbines

    Directory of Open Access Journals (Sweden)

    Marian-Dumitru Nedeloni

    2017-11-01

    Full Text Available This paper presents some information regarding the hydraulic turbines respectively the experimental results on cavitation erosion behavior of a 13Cr-4Ni stainless steel used to manufacture the components exposed to water of the Francis, Kaplan and Pelton hydraulic turbines. So, the presented experimental results of this paper highlight the good cavitation erosion resistance of the analyzed 13Cr-4Ni stainless steel.

  4. A Modified HR3C Austenitic Heat-Resistant Steel for Ultra-supercritical Power Plants Applications Beyond 650 °C

    Science.gov (United States)

    Zhu, C. Z.; Yuan, Y.; Zhang, P.; Yang, Z.; Zhou, Y. L.; Huang, J. Y.; Yin, H. F.; Dang, Y. Y.; Zhao, X. B.; Lu, J. T.; Yan, J. B.; You, C. Y.

    2018-02-01

    A modified HR3C austenitic steel has been designed by optimizing the chemical composition. Compared with a commercial HR3C alloy, the modified steel has comparable oxidation resistance, yield strength, and plasticity, but higher creep rupture strength and impact toughness after long-term thermal exposure. The results suggest that the modified alloy is a promising candidate for the applications of ultra-supercritical power plants operating beyond 650 °C.

  5. Effect of Low-Cycle Thermocycling Treatment on Corrosion and Mechanical Properties of Corrosion-Resistant Steel 12Kh18N10T Irradiated with Neutrons

    Science.gov (United States)

    Yarovchuk, A. V.; Maksimkin, O. P.; Tsay, K. V.

    2017-11-01

    The effect of thermocycling treatment on the susceptibility to local corrosion and mechanical characteristics of corrosion-resistant steel 12Kh18N10T in different states (after austenitizing, cold rolling, and neutron irradiation) is considered. The possibility of partial recovery of the corrosion and mechanical characteristics of irradiated reactor steel due to low-cycle thermocycling in a temperature range exceeding the irradiation temperature is demonstrated.

  6. Microstructure Control of Fire-resistant, Low-alloy Steel; An in-situ 3D X-ray Diffraction and A Small-angle X-ray Scattering Study

    NARCIS (Netherlands)

    Dere, E.G.

    2013-01-01

    The research presented in this thesis aims at deepening our understanding of the formation of the microstructure of steel during thermal processing in order to control the microstructure and thereby improve the fire-resistance of low-alloy steel. The strength of steel decreases during a fire mainly

  7. Microstructure Control of Fire-resistant, Low-alloy Steel; An in-situ 3D X-ray Diffraction and A Small-angle X-ray Scattering Study

    NARCIS (Netherlands)

    Sietsma, J.; Offerman, S.E.; Dere, E.G.

    The research presented in this thesis aims at deepening our understanding of the formation of the microstructure of steel during thermal processing in order to control the microstructure and thereby improve the fire-resistance of low-alloy steel. The strength of steel decreases during a fire mainly

  8. High-throughput design of low-activation, high-strength creep-resistant steels for nuclear-reactor applications

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Qi; Zwaag, Sybrand van der [Novel Aerospace Materials Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands); Xu, Wei, E-mail: xuwei@ral.neu.edu.cn [State Key Laboratory of Rolling and Automation, Northeastern University, 110819, Shenyang (China); Novel Aerospace Materials Group, Faculty of Aerospace Engineering, Delft University of Technology, Kluyverweg 1, 2629 HS, Delft (Netherlands)

    2016-02-15

    Reduced-activation ferritic/martensitic steels are prime candidate materials for structural applications in nuclear power reactors. However, their creep strength is much lower than that of creep-resistant steel developed for conventional fossil-fired power plants as alloying elements with a high neutron activation cannot be used. To improve the creep strength and to maintain a low activation, a high-throughput computational alloy design model coupling thermodynamics, precipitate-coarsening kinetics and an optimization genetic algorithm, is developed. Twelve relevant alloying elements with either low or high activation are considered simultaneously. The activity levels at 0–10 year after the end of irradiation are taken as optimization parameter. The creep-strength values (after exposure for 10 years at 650 °C) are estimated on the basis of the solid-solution strengthening and the precipitation hardening (taking into account precipitate coarsening). Potential alloy compositions leading to a high austenite fraction or a high percentage of undesirable second phase particles are rejected automatically in the optimization cycle. The newly identified alloys have a much higher precipitation hardening and solid-solution strengthening at the same activity level as existing reduced-activation ferritic/martensitic steels.

  9. A new 12% chromium steel strengthened by Z-phase precipitates

    DEFF Research Database (Denmark)

    Liu, Fang; Rashidi, Masoud; Johansson, Lennart

    2016-01-01

    In order to increase the corrosion resistance and simultaneously maintain the creep resistance of 9-12% Cr steels at 650 degrees C, a new alloy design concept was proposed, using thermodynamically stable Z-phase (CrTaN) precipitates to strengthen the steel. A new trial Z-phase strengthened 12% Cr...... steel was produced and creep tested. The steel exhibited good long-term creep resistance. Dense nano-sized Z-phase precipitates were formed at an early stage, and coarsened slowly. They remained small after more than 10,000 h. (C) 2015 Elsevier Ltd. All rights reserved....

  10. Effect of Carbon Content on Microstructure and Mechanical Properties of 9 to 12 pct Cr Ferritic/Martensitic Heat-Resistant Steels

    Science.gov (United States)

    Yin, Feng-Shi; Tian, Li-Qian; Xue, Bing; Jiang, Xue-Bo; Zhou, Li

    2012-07-01

    Two heats of 9 to 12 pct Cr ferritic/martensitic heat-resistant steels were prepared. One has an ultralow carbon content of 0.01 wt pct, whereas another heat has a normal carbon content of 0.09 wt pct. The effect of carbon content on microstructure and mechanical properties of 9 to 12 pct Cr ferritic/martensitic heat-resistant steels was studied. The results show that the ultralow-carbon steel contains bimodal, nanosized MX precipitates with high density in the matrix but few M23C6 carbide particles in the normalized-and-tempered state. The smaller nanosized MX precipitates have two kinds of typical morphology: One is cubic and another is rectangular. The cubic MX precipitate contains Nb, Ti, and V, whereas the rectangular one only contains Nb and V. The normal carbon steel has abundant M23C6 carbide particles along the grain and lath boundaries and much less density of nanosized MX precipitates after the same heat treatments. After long-term aging at 923 K (650 °C) for 10,000 hours, the stress rupture properties of the ultralow carbon content steel degrades more significantly. The strength degradation mechanism of the 9 to 12 pct Cr ferritic/martensitic heat-resistant steels is discussed in this article.

  11. Formation of Wear Resistant Steel Surfaces by Plasma Immersion Ion Implantation

    Science.gov (United States)

    Mändl, S.; Rauschenbach, B.

    2003-08-01

    Plasma immersion ion implantation (PIII) is a versatile and fast method for implanting energetic ions into large and complex shaped three-dimensional objects where the ions are accelerated by applying negative high voltage pulses to a substrate immersed in a plasma. As the line-of-sight restrictions of conventional implanters are circumvented, it results in a fast and cost-effective technology. Implantation of nitrogen at 30 - 40 keV at moderate temperatures of 200 - 400 °C into steel circumvents the diminishing thermal nitrogen activation encountered, e.g., in plasma nitriding in this temperature regime, thus enabling nitriding of additional steel grades. Nitride formation and improvement of the mechanical properties after PIII are presented for several steel grades, including AISI 316Ti (food industry), AISI D2 (used for bending tools) and AISI 1095 (with applications in the textile industry).

  12. Cast, heat-resistant austenitic stainless steels having reduced alloying element content

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Pankiw, Roman I [Greensburg, PA

    2010-07-06

    A cast, austenitic steel composed essentially of, expressed in weight percent of the total composition, about 0.4 to about 0.7 C, about 20 to about 30 Cr, about 20 to about 30 Ni, about 0.5 to about 1 Mn, about 0.6 to about 2 Si, about 0.05 to about 1 Nb, about 0.05 to about 1 W, about 0.05 to about 1.0 Mo, balance Fe, the steel being essentially free of Ti and Co, the steel characterized by at least one microstructural component selected from the group consisting of MC, M.sub.23C.sub.6, and M(C, N).

  13. Cast, heat-resistant austenitic stainless steels having reduced alloying element content

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Pankiw, Roman I [Greensburg, PA

    2011-08-23

    A cast, austenitic steel composed essentially of, expressed in weight percent of the total composition, about 0.4 to about 0.7 C, about 20 to about 30 Cr, about 20 to about 30 Ni, about 0.5 to about 1 Mn, about 0.6 to about 2 Si, about 0.05 to about 1 Nb, about 0.05 to about 1 W, about 0.05 to about 1.0 Mo, balance Fe, the steel being essentially free of Ti and Co, the steel characterized by at least one microstructural component selected from the group consisting of MC, M.sub.23C.sub.6, and M(C, N).

  14. Corrosion resistance of stainless steels and high Ni-Cr alloys to acid fluoride wastes

    Energy Technology Data Exchange (ETDEWEB)

    Smith, H.D.; Mackey, D.B.; Pool, K.H. (Pacific Northwest Lab., Richland, WA (United States)); Schwenk, E.B. (Westinghouse Hanford Co., Richland, WA (United States))

    1992-04-01

    TRUEX processing of Hanford Site waste will utilize potentially corrosive acid fluoride processing solutions. Appropriate construction materials for such a processing facility need to be identified. Toward this objective, candidate stainless steels and high Ni-Cr alloys have been corrosion tested in simulated acid fluoride process solutions at 333K. The high Ni-Cr alloys exhibited corrosion rates as low as 0.14 mm/y in a solution with an HF activity of about 1.2 M, much lower than the 19 to 94 mm/y observed for austenitic stainless steels. At a lower HF activity (about 0.008 M), stainless steels display delayed passivation while high Ni-Cr alloys display essentially no reaction.

  15. RESEARCH OF INFLUENCE OF LIQUID ALUMINUM ON RESISTANCE OF THE STEEL AND CAST-IRON TOOL

    Directory of Open Access Journals (Sweden)

    S. S. Zhizhchenko

    2013-01-01

    Full Text Available The study of the interaction of steel and cast iron with aluminum was performed by immersion, and isothermal holding. By optical and electron microscopy, the microstructure of the reaction zone was investigated. The partial enthalpy of dissolution of iron, steel and cast iron in liquid aluminum has been investigated by high-temperature calorimetry at 1773 K. X-ray analysis and microhardness measurements was used to study the phase composition of the reaction zone. The thermodynamic descriptions of the system Al–Fe and Al–C–Fe are performed within the CALPHAD-method.

  16. J-R Fracture Resistance of SA533 Gr.B-Cl.1 Steel for Reactor Pressure Vessel

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Ji-Hyun; Hong, Seokmin; Lee, Bong-Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    A rolled plate might show different mechanical behaviors from a forging, even though they contain same chemical compositions. Furthermore, it is known that the fracture behavior of a rolled plate is very sensitive to material orientation comparing to a forging. In this study, the J-R fracture resistances of SA533 Gr.B-Cl.1 plate were measured at reactor operating temperature and the material orientation sensitivity was discussed. The decrease of fracture resistance of this kind of low alloy steel at an elevated temperature is known as the effect of dynamic strain aging (DSA). It was attributed to that the carbides and grains elongated to primary rolling direction, so that the aspect ratio of carbides and grains in the specimen with T-L orientation is larger. Generally, the hard second phase could take a roll of trigger point of unstable fracture. It is needed that the fracture surfaces of the tested specimens to be examined profoundly.

  17. Colistin and tigecycline resistance in carbapenemase-producing Gram-negative bacteria: emerging resistance mechanisms and detection methods.

    Science.gov (United States)

    Osei Sekyere, J; Govinden, U; Bester, L A; Essack, S Y

    2016-09-01

    A literature review was undertaken to ascertain the molecular basis for tigecycline and colistin resistance mechanisms and the experimental basis for the detection and delineation of this resistance particularly in carbapenemase-producing Gram-negative bacteria. Pubmed, Google Scholar and Science Direct were searched with the keywords colistin, tigecycline, resistance mechanisms and detection methods. Trans-complementation and comparative MIC studies, mass spectrometry, chromatography, spectrofluorometry, PCR, qRT-PCR and whole genome sequencing (WGS) were commonly used to determine tigecycline and colistin resistance mechanisms, specifically modifications in the structural and regulatory efflux (acrAB, OqxAB, kpgABC adeABC-FGH-IJK, mexAB-XY-oprJM and soxS, rarA robA, ramRAB marRABC, adeLRS, mexRZ and nfxb) and lipid A (pmrHFIJFKLM, lpxA, lpxC lpxD and mgrB, pmrAB, phoPQ,) genes respectively. Mutations in the ribosomal 16S rRNA operon rrnBC, also yielded resistance to tigecycline through target site modifications. The mcr-1 gene conferring resistance to colistin was identified via WGS, trans-complementation and a murine thigh infection model studies. Common detection methods are mainly antibiotic sensitivity testing with broth microdilution while molecular identification tools are mostly PCR and WGS. Spectrofluorometry, MALDI-TOF MS, micro-array and real-time multiplex PCR hold much promise for the future as new detection tools. © 2016 The Society for Applied Microbiology.

  18. Effects of boundary characteristics on resistance to temper embrittlement and segregation behavior of Ni-Cr-Mo low alloy steel

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang-Gyu; Lee, Ki-Hyoung [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Kim, Min-Chul, E-mail: mckim@kaeri.re.kr [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon 305-353 (Korea, Republic of); Lee, Bong-Sang [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, Daedeok-daero 989-111, Yuseong-gu, Daejeon 305-353 (Korea, Republic of)

    2013-01-20

    SA508 Gr.4N Ni-Cr-Mo low alloy steel has higher strength and fracture toughness than those of commercial SA508 Gr.3 low alloy steel, due to its tempered martensitic microstructure as well as the solid solution effect and its higher contents of Ni and Cr. Hence, several studies have been performed on SA508 Gr.4N for nuclear application. In this study, the effects of microstructure on temper embrittlement and segregation behaviors in Ni-Cr-Mo low alloy steel were evaluated from the viewpoint of grain boundary characteristics. To evaluate the microstructural effect while excluding chemistry effects, the same heat was used but different microstructure samples were prepared by changing the cooling rate after austenitization. The increased volume fraction of martensite reduces the resistance to temper embrittlement, showing an increased transition-temperature shift (TTS) and increased P segregation at prior austenite boundaries. The segregation occurred intensively at prior austenite grain boundaries in tempered martensite, while the segregation occurred simultaneously at both prior austenite boundaries and packet boundaries in tempered bainite. In the EBSD results, most of the packet boundaries in tempered martensite are special boundaries such as N-Ary-Summation 3 coincident site lattice (CSL) boundaries. The differences in P segregation between tempered martensite and tempered bainite are mainly caused by different portions of low energy special boundaries among the sub-grain boundaries. The reduction of temper embrittlement resistance in tempered martensite could be explained by the increased fraction of low energy CSL boundaries, which leads to a concentrated segregation of P at prior austenite grain boundaries.

  19. Intermetallic diffusion coatings for enhanced hot-salt oxidation resistance of nitrogen-containing austenitic stainless steels

    Science.gov (United States)

    Mudali, U. Kamachi; Bhuvaneswaran, N.; Shankar, P.; Khatak, H. S.; Raj, B.

    2004-06-01

    This article presents the preparation, characterization, and hot-salt oxidation behavior of nitrogen-containing type 316L stainless steel (SS), surface modified with intermetallic coatings. Three different types of intermetallic coating systems, containing aluminum, titanium, and titanium/aluminum multilayers, were formed by diffusion annealing of type 316L austenitic SS containing 0.015, 0.1, 0.2, and 0.56 pct nitrogen. Analysis by using X-ray diffraction (XRD), scanning electron microscopy (SEM), and secondary ion mass spectroscopy (SIMS) confirmed the formation of various intermetallic phases such as AIN, Al13Fe4, FeAl2, FeTi, Ti2N, and Ti3Al in the coatings. Hot salt oxidation behavior of the uncoated and surface-modified stainless steels was assessed by periodic monitoring of the weight changes of NaCl salt-applied alloys kept in an air furnace at 1023 K up to 250 hours. The oxide scales formed were examined by XRD and stereomicroscopy. Among the various surface modifications investigated in the present study, the results indicate that the titanium-modified alloys show the best hot-salt oxidation resistance with the formation of an adherent, protective, thin, and continuous oxide layer. Among the four N-containing alloys investigated, the titanium and Ti/Al multilayer modified 0.56 pct N alloy showed the best hot-salt oxidation resistance as compared to uncoated alloys. The slower corrosion kinetics and adherent scale morphology indicate that the surface-modified titanium intermetallic coatings could provide high-temperature service applications up to 1073 K, particularly in chloride containing atmospheres, for austenitic stainless steels.

  20. Influence of pre-deformation, sensitization and oxidation in high temperature water on corrosion resistance of AISI 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Jinlong, E-mail: ljltsinghua@126.com [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Liang, Tongxiang [Beijing Key Laboratory of Fine Ceramics, Institute of Nuclear and New Energy Technology, Tsinghua University, Zhongguancun Street, Haidian District, Beijing 100084 (China); State Key Lab of New Ceramic and Fine Processing, Tsinghua University, Beijing 100084 (China); Luo, Hongyun [Key Laboratory of Aerospace Materials and Performance (Ministry of Education), School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Xueyuan Road 37, Beijing 100191 (China)

    2016-12-01

    Highlights: • The pre-strain accelerated desensitization and sensitization for austenitic stainless steels. • Low temperature sensitization (carbide precipitation) induced α′-martensite. • The sensitization level could affect directly corrosion resistance of the oxide film. - Abstract: The effects of pre-deformation on sensitization of AISI 304 stainless steel were investigated by the double loop electrochemical potentiokinetic reactivation test. The effects of pre-deformation and sensitization on high temperature oxidized film formed in high temperature water were analyzed by a XRD and SEM. The electrochemical impedance spectroscopy at room temperature was used to study corrosion resistance of oxidized film. The point defect density of oxidized film was calculated by Mott–Schottky plots. The results showed that the value of the degree of sensitization first decreased and then slight increased with the increasing of engineering strain. Moreover, low temperature promoted to form sensitization induced “secondary” α′-martensite. The sample with 20% engineering strain had higher impedance value than other samples. The result was supported by further Mott–Schottky experiments. Considering increased α′-martensite with the increasing of strain, the results of the impedance were more consistent with values of the degree of sensitization.

  1. Improvement in the corrosion resistance of carbon steel in acidic condition using naphthalen-2-ylnaphthalene-2-carboxammide inhibitor.

    Science.gov (United States)

    Kannan, Perumal; Rao, Toleti Subba; Rajendran, Nallaiyan

    2017-09-18

    In the present investigation, the anti corrosive performance of synthesized Naphthalen-2-yl Naphthalene-2-Carboxammide (NNC) in 1 N HCl solution as corrosion inhibitor on carbon steel was studied at room temperature. Potentiodynamic polarization study revealed the mixed behavior of the inhibitor NNC along with inhibition efficiency. The inhibition efficiency of NNC increases with increasing inhibitor concentration. The electrochemical noise analysis (ENA) and electrochemical impedance spectroscopy (EIS) studies have showed that noise resistance (Rn) and charge transfer resistance (Rct) values were increased with addition of inhibitor concentrations. The synthesized and adsorbed bonds of inhibitor with the metal atom were characterized by ATR-FTIR spectroscopy. The adsorption isotherm explored that the adsorption of NNC obeyed Langmuir adsorption to bond with metal surface at carbon steel/HCl solution interface. The thermodynamic properties were calculated to discuss the adsorption mechanism of corrosion inhibition. Atomic force microscope (AFM) study showed a less corroded and roughness surface morphology, which is due to the formation of protective film layer on the surface. Quantum chemical parameters were calculated and correlated with respect to inhibitive performance of NNC. The study revealed that the adsorption nature of inhibitor has both physisorption and chemisorption phenomena. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Effect of thermal treatment on the corrosion resistance of Type 316L stainless steel exposed in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Jiao, Y. [Department of Materials Science & Engineering, McMaster University, Hamilton, ON (Canada); Zheng, W. [CanmetMATERIALS, Natural Resources Canada, Hamilton, ON (Canada); Guzonas, D.A. [Canadian Nuclear Laboratories Chalk River Laboratories, ON (Canada); Cook, W.G. [Department of Chemical Engineering, University of New Brunswick, Fredericton, NB (Canada); Kish, J.R., E-mail: kishjr@mcmaster.ca [Department of Materials Science & Engineering, McMaster University, Hamilton, ON (Canada)

    2015-09-15

    There are still unknown aspects about the growth mechanism of oxide scales formed on candidate stainless steel fuel cladding materials during exposure in supercritical water (SCW) under the conditions relevant to the Canadian supercritical water-cooled reactor (SCWR). The tendency for intermetallic precipitates to form within the grains and on grain boundaries during prolonged exposure at high temperatures represents an unknown factor to corrosion resistance, since they tend to bind alloyed Cr. The objective of this study was to better understand the extent to which intermetallic precipitates affects the mode and extent of corrosion in SCW. Type 316L stainless steel, used as a model Fe–Cr–Ni–Mo alloy, was exposed to 25 MPa SCW at 550 °C for 500 h in a static autoclave for this purpose. Mechanically-abraded samples were tested in the mill-annealed (MA) and a thermally-treated (TT) condition. The thermal treatment was conducted at 815 °C for 1000 h to precipitate the carbide (M{sub 23}C{sub 6}), chi (χ), laves (η) and sigma (σ) phases. It was found that although relatively large intermetallic precipitates formed at the scale/alloy interface locally affected the oxide scale formation, their discontinuous formation did not affect the short-term overall apparent corrosion resistance.

  3. Effect of thermal treatment on the corrosion resistance of Type 316L stainless steel exposed in supercritical water

    Science.gov (United States)

    Jiao, Y.; Zheng, W.; Guzonas, D. A.; Cook, W. G.; Kish, J. R.

    2015-09-01

    There are still unknown aspects about the growth mechanism of oxide scales formed on candidate stainless steel fuel cladding materials during exposure in supercritical water (SCW) under the conditions relevant to the Canadian supercritical water-cooled reactor (SCWR). The tendency for intermetallic precipitates to form within the grains and on grain boundaries during prolonged exposure at high temperatures represents an unknown factor to corrosion resistance, since they tend to bind alloyed Cr. The objective of this study was to better understand the extent to which intermetallic precipitates affects the mode and extent of corrosion in SCW. Type 316L stainless steel, used as a model Fe-Cr-Ni-Mo alloy, was exposed to 25 MPa SCW at 550 °C for 500 h in a static autoclave for this purpose. Mechanically-abraded samples were tested in the mill-annealed (MA) and a thermally-treated (TT) condition. The thermal treatment was conducted at 815 °C for 1000 h to precipitate the carbide (M23C6), chi (χ), laves (η) and sigma (σ) phases. It was found that although relatively large intermetallic precipitates formed at the scale/alloy interface locally affected the oxide scale formation, their discontinuous formation did not affect the short-term overall apparent corrosion resistance.

  4. Molecular characterization of metallo β-lactamase producing multidrug resistant Pseudomonas aeruginosa from various clinical samples.

    Science.gov (United States)

    Ramakrishnan, Kalaivani; Rajagopalan, Saranathan; Nair, Shashikala; Kenchappa, Prashanth; Chandrakesan, Sheela Devi

    2014-01-01

    Pseudomonas aeruginosa is a potent opportunistic nosocomial human pathogen among Gram-negative bacteria causing various life-threatening infections in patients from Intensive Care Units. This bacterium has become resistant to almost all commonly available antibiotics with limited treatment options. Multi drug resistant P. aeruginosa (MDRPA) is a major cause of concern among hospital acquired infections. It uses distinctive resistant mechanisms virtually to all the available antibiotics such as Metallo β-lactamases (MBL) production, extended spectrum β-lactamase production (ESBL), up regulation of efflux systems related genes and decreased outer membrane permeability. This study was carried out to find one the predominant resistance mechanisms among MDRPA and the prevalence of corresponding resistance genes. MDRPA isolates collected from various clinical samples for a period of 1-year (November 2009-Octo ber 2010) were included to detect the predominant mechanism of resistance using phenotypic and molecular methods. Molecular characterization of all these isolates was done by polymerase chain reaction (PCR) for the presence of blaVIM-₂, blaIMP-₁, blaOXA-₂₃, and blaNDM-₁ genes with specific primers. Among 75 MDRPA isolates 84% (63) were MBL producers. Molecular characterization studied by PCR showed the presence of blaVIM-₂ gene in 13% of MBL producers. The prevalence of MBLs has been increasing worldwide, particularly among P. aeruginosa, leading to severe limitations in the therapeutic options for the management. Thus, proper resistance screening measures and appropriate antibiotic policy can be strictly adopted by all the healthcare facility providers to overcome these superbugs.

  5. Antibiotic resistance and integrons in Shiga toxin-producing Escherichia coli (STEC

    Directory of Open Access Journals (Sweden)

    Rocío Colello

    2015-03-01

    Full Text Available Shiga toxin-producing Escherichia coli (STEC cause hemorrhagic colitis (HC and hemolytic-uremic syndrome in humans (HUS. Cattle are the main reservoir of STEC and transmission to humans occurs through contaminated food and water. Antibiotics are used in pig production systems to combat disease and improve productivity and play a key role in the dissemination of antibiotic resistance genes to the bacteria. Integrons have been identified in resistant bacteria allowing for the acquisition and dissemination of antibiotic resistance genes. STEC strains isolated from humans and animals have developed antibiotic resistance. In our laboratory, 21 non-157 STEC strains isolated from pigs were analyzed to detect class 1 and 2 integrons by PCR. Eight carried integrons, 7 of them harbored intl2. In another study 545 STEC strains were also analyzed for the presence of intl1 and intl2. Strains carrying intl1 belonged to isolates from environment (n = 1, chicken hamburger (n = 2, dairy calves (n = 4 and pigs (n = 8. Two strains isolated from pigs harbored intl2 and only one intl1/intl2, highlighting the presence of intl2 in pigs. The selection for multiresistant strains may contribute to the emergence of antibiotic resistant pathogens and facilitate the spreading of the mobile resistance elements to other bacteria.

  6. Nondestructive evaluation for remanent life of aged 12Cr ferrite heat resisting steel by reversible permeability

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Kwon-Sang, E-mail: ryuks@kriss.re.kr [Korea Research Institute of Standards and Science, Centre for Materials Measurement, Doryong Dong, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); Kim, Chung-Seok [Automotive Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Baek, Un-bong [Korea Research Institute of Standards and Science, Centre for Materials Measurement, Doryong Dong, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); Lee, Jong Suk [Gangneung-Wonju National University, Wonju 220-711 (Korea, Republic of)

    2013-01-15

    We present a magnetic and nondestructive method to evaluate the remanent life of advanced ferritic steel using the value of reversible permeability. The method to measure reversible permeability is based on the theory that the value of reversible permeability is the same differential of the hysteresis loop. The measurement principle is based on the foundation of harmonics voltage induced in a sensing coil using a lock-in amplifier tuned to the frequency of the exciting one. Results obtained for reversible permeability, Vickers hardness, and tensile strength on the aged samples show that the peak interval of reversible permeability, Vickers hardness and tensile strength decrease as aging time increases. We could estimate the remanent life of advanced ferritic steel by using the relationship between the peak interval of reversible permeability and the Larson-Miller parameter, non-destructively. - Highlights: Black-Right-Pointing-Pointer Magnetic, nondestructive evaluation method of remanent life of 12Cr ferritic steel is presented. Black-Right-Pointing-Pointer Peak interval of reversible permeability decreases with the increase of aging time. Black-Right-Pointing-Pointer Mechanical properties decrease with the increase of aging time. Black-Right-Pointing-Pointer Magnetic and mechanical properties are decreased with increase of Larson-Miller parameter. Black-Right-Pointing-Pointer Reversible permeability is nondestructively used to estimate remanent life of 12Cr ferrite steel.

  7. Corrosion Resistance of Steel 45 Subjected to Electromechanical Treatment and Surface Plastic Deformation

    Science.gov (United States)

    Dudkina, N. G.

    2018-01-01

    The corrosion properties of normalized steel 45 are studied after a combined hardening of its surface layer, which consists of electromechanical treatment and surface plastic deformation (EMT + SPD). The effect of different aggressive environments on the structure, microhardness and corrosion rate of the hardened surface layer is determined.

  8. Corrosion resistance of Zn-Co-Fe alloy coatings on high strength steel

    NARCIS (Netherlands)

    Lodhi, Z.F.; Mol, J.M.C.; Hovestad, A.; Hoen-Velterop, L. 't; Terryn, H.; Wit, J.H.W.de

    2009-01-01

    The corrosion properties of electrodeposited zinc-cobalt-iron (Zn-Co-Fe) alloys (up to 40 wt.% Co and 1 wt.% Fe) on steel were studied by using various electrochemical techniques and compared with zinc (Zn) and cadmium (Cd) coatings in 3.5% NaCl solution. It was found that with an increase in Co

  9. Austenitic stainless steel alloys having improved resistance to fast neutron-induced swelling

    Science.gov (United States)

    Bloom, Everett E.; Stiegler, James O.; Rowcliffe, Arthur F.; Leitnaker, James M.

    1977-03-08

    The present invention is based on the discovery that radiation-induced voids which occur during fast neutron irradiation can be controlled by small but effective additions of titanium and silicon. The void-suppressing effect of these metals in combination is demonstrated and particularly apparent in austenitic stainless steels.

  10. Study made of corrosion resistance of stainless steel and nickel alloys in nuclear reactor superheaters

    Science.gov (United States)

    Greenberg, S.; Hart, R. K.; Lee, R. H.; Ruther, W. E.; Schlueter, R. R.

    1967-01-01

    Experiments performed under conditions found in nuclear reactor superheaters determine the corrosion rate of stainless steel and nickel alloys used in them. Electropolishing was the primary surface treatment before the corrosion test. Corrosion is determined by weight loss of specimens after defilming.

  11. Recent advances in creep-resistant steels for power plant applications

    Indian Academy of Sciences (India)

    The higher steam temperatures and pressures required to achieve increase in thermal efficiency of fossil fuel-fired power-generation plants necessitate the use of steels ... Research Centre Jülich, Institute for Materials and Processes in Energy Systems, IWV-2, D-52425 Jülich, Germany; University of Mining and Metallurgy, ...

  12. Simultaneous activation of salicylate production and fungal resistance in transgenic chrysanthemum producing caffeine

    Science.gov (United States)

    Kim, Yun-Soo; Lim, Soon; Yoda, Hiroshi; Choi, Chang-Sun; Choi, Yong-Eui

    2011-01-01

    Caffeine functions in the chemical defense against biotic attackers in a few plant species including coffee and tea. Transgenic tobacco plants that endogenously produced caffeine by expressing three N-methyltransferases involved in the caffeine biosynthesis pathway exhibited a strong resistance to pathogens and herbivores. Here we report that transgenic Chrysanthemum, which produced an equivalent level of caffeine as the tobacco plants at approximately 3 µg g−1 fresh tissues, also exhibited a resistance against grey mold fungal attack. Transcripts of PR-2 gene, a marker for pathogen response, were constitutively accumulated in mature leaves without pathogen attack. The levels of salicylic acid and its glucoside conjugate in mature leaves of the transgenic lines were found to be 2.5-fold higher than in the wild type control. It is suggested that endogenous caffeine stimulated production and/or deposition of salicylates, which possibly activated a series of defense reactions even under non-stressed conditions. PMID:21346420

  13. Simultaneous activation of salicylate production and fungal resistance in transgenic Chrysanthemum producing caffeine.

    Science.gov (United States)

    Kim, Yun-Soo; Lim, Soon; Yoda, Hiroshi; Choi, Yong-Eui; Sano, Hiroshi

    2011-03-01

    Caffeine functions in the chemical defense against biotic attackers in a few plant species, including coffee and tea. Transgenic tobacco plants that endogenously produced caffeine by expressing three N-methyltransferases involved in the caffeine biosynthesis pathway exhibited a strong resistance to pathogens and herbivores. Here we report that transgenic Chrysanthemum, which produced an equivalent level of caffeine as the tobacco plants at approximately 3 μg g(-1) fresh tissues, also exhibited a resistance against grey mold fungal attack. Transcripts of PR-2 gene, a marker for pathogen response, were constitutively accumulated in mature leaves without pathogen attack. The levels of salicylic acid and its glucoside conjugate in mature leaves of the transgenic lines were found to be 2.5-fold higher than in the wild type control. It is suggested that endogenous caffeine stimulated production and/or deposition of salicylates, which possibly activated a series of defense reactions even under non-stressed conditions.

  14. Open Conversion after Aortic Endograft Infection Caused by Colistin-Resistant, Carbapenemase-Producing Klebsiella pneumoniae.

    Science.gov (United States)

    Montelione, Nunzio; Menna, Danilo; Sirignano, Pasqualino; Capoccia, Laura; Mansour, Wassim; Speziale, Francesco

    2016-10-01

    A 62-year-old man presented with fever, abdominal pain, and malaise 13 months after emergency endovascular aortic repair. Computed tomographic angiograms showed a periprosthetic fluid and gas collection, so infection was diagnosed. Open conversion was performed, involving endograft explantation and in situ aortic reconstruction. Cultures and the explanted prosthesis were positive for carbapenemase-producing Klebsiella pneumoniae, resistant to colistin. Because of the sparse data on endograft infections caused by this pathogen, we placed the patient on an empiric double-carbapenem regimen for 4 weeks. Symptomatic recovery occurred after 21 days. On the 30th day, we deployed a stent to treat a new pseudoaneurysm. Three years later, the patient had no signs of persistent or recurrent infection. We think that this is the first report of aortic endograft infection caused by colistin-resistant, carbapenemase-producing K. pneumoniae.

  15. Definitions of Resistance and Deformation Capacity for Non-Sway Steel and Composite Structures

    NARCIS (Netherlands)

    Steenhuis, C.M.; Vrouwenvelder, A.C.W.M.; Van Herwijnen, F.; Snijder, H.H.

    2002-01-01

    Resistance, stiffness and deformation capacity are three characteristics describing the behaviour of (statically loaded) structures. The stiffness relates mostly to the serviceability of the structure. The resistance and deformation capacity relate to the safety of the structure. Nowadays, the

  16. Characterization of Multidrug Resistant ESBL-Producing Escherichia coli Isolates from Hospitals in Malaysia

    Directory of Open Access Journals (Sweden)

    King-Ting Lim

    2009-01-01

    Full Text Available The emergence of Escherichia coli that produce extended spectrum β-lactamases (ESBLs and are multidrug resistant (MDR poses antibiotic management problems. Forty-seven E. coli isolates from various public hospitals in Malaysia were studied. All isolates were sensitive to imipenem whereas 36 were MDR (resistant to 2 or more classes of antibiotics. PCR detection using gene-specific primers showed that 87.5% of the ESBL-producing E. coli harbored the blaTEM gene. Other ESBL-encoding genes detected were blaOXA, blaSHV, and blaCTX-M. Integron-encoded integrases were detected in 55.3% of isolates, with class 1 integron-encoded intI1 integrase being the majority. Amplification and sequence analysis of the 5′CS region of the integrons showed known antibiotic resistance-encoding gene cassettes of various sizes that were inserted within the respective integrons. Conjugation and transformation experiments indicated that some of the antibiotic resistance genes were likely plasmid-encoded and transmissible. All 47 isolates were subtyped by PFGE and PCR-based fingerprinting using random amplified polymorphic DNA (RAPD, repetitive extragenic palindromes (REPs, and enterobacterial repetitive intergenic consensus (ERIC. These isolates were very diverse and heterogeneous. PFGE, ERIC, and REP-PCR methods were more discriminative than RAPD in subtyping the E. coli isolates.

  17. Effect of chemical compositions and heat treatment on IGSCC resistance for strain hardened low carbon austenitic stainless steels in oxygenated water

    Energy Technology Data Exchange (ETDEWEB)

    Yonezawa, T. [FRRI, Graduate School of Engineering, Tohoku University (Japan); Kanasaki, H.; Fujimoto, K.; Taneike, M. [Takasago R-D Center, Mitsubishi Heavy Industries (Japan); Ooki, S.; Sueishi, Y.; Tezuka, H.; Takamori, K.; Suzuki, S. [Materials Engineering Center, R-D Center, Tokyo Electric Power Company (Japan)

    2011-07-01

    In order to develop the highly resistant alternative materials to intergranular stress corrosion cracking (IGSCC) for the non-sensitized and strain hardened low carbon austenitic stainless steel in oxygenated water, the effects of chemical compositions and heat treatment conditions on the IGSCC resistance and stacking fault energy (SFE) values were studied for 33 laboratory melted steels and commercial type 310S stainless steel. The IGSCC resistance for test materials was compared by the maximum crack length, average crack length and cracked area in fatigue pre-cracked CT specimens after SCC test in oxygenated high temperature water. SFE values for these test materials were measured by the transmission electron microscopy on the width of isolated extended dislocations under g-3g weak beam condition for thin foils taken from the test materials, in this study. From these experiments, the effects of the chromium, molybdenum, nitrogen, silicon and manganese contents on the SCC resistance for non-aged materials were not so pronounced in this study. It is strongly suggested that the SFE value is a key parameter for the IGSCC resistance of the aged or non-aged and strain hardened low carbon austenitic stainless steels. (authors)

  18. Microstructures and Mechanical Properties of Dissimilar Al/Steel Butt Joints Produced by Autogenous Laser Keyhole Welding

    Directory of Open Access Journals (Sweden)

    Li Cui

    2017-11-01

    Full Text Available Dissimilar Al/steel butt joints of 6.0 mm thick plates have been achieved using fiber laser keyhole welding autogenously. The cross sections, interface microstructures, hardness and tensile properties of Al/steel butt joints obtained under different travel speeds and laser beam offsets were investigated. The phase morphology and thickness of the intermetallic compound (IMC layers at the interface were analyzed by scanning electronic microscopes (SEM using the energy-dispersive spectrometry (EDS and electron back-scattered diffraction (EBSD techniques. The results show that travel speeds and laser beam offsets are of considerable importance for the weld shape, morphology and thickness of IMC layers, and ultimate tensile strength (UTS of Al/steel butt joints. This proves that the IMC layers consist of Fe2Al5 phases and Fe4Al13 phases by EBSD phase mapping. Increasing laser beam offsets from 0.3 mm to 0.7 mm significantly decreases the quantity of Fe4Al13 phases and the thickness of Fe2Al5 layers at the interface. During tensile processing, the Fe2Al5 layer with the weakest bonding strength is the most brittle region at the interface. However, an intergranular fracture that occurred at Fe2Al5 layers leads to a relatively high UTS of Al/steel butt joints.

  19. A new integration of hot pressing and carbon partition process to produce high strength steel components with better toughness

    Directory of Open Access Journals (Sweden)

    Zhang Shi-hong

    2015-01-01

    Full Text Available A novel one step method for hot pressing and quench & partition (Q&P integration – hot Pressing-dynamic partitioning (HP-DP process is presented, which can be processed by regular hot pressing equipment and process. The HP-DP formed steel is an upgrade of the existing hot pressed steel especially suitable for making high strength components with superior crashworthiness due to better toughness. Corresponding steel sheet based on conventional 22MnB5 is designed and prepared. After that, the physical simulation experiments for HP-DP are carried out on thermal-mechanical simulator. Microstructure of the steel subjected to HP-DP treatment, with a typical Q&P treated feature, is mainly composed of initial quenched martensite phase, final quenched martensite phase and retained austenite phase, which indicate the occurrence of carbon diffusion concomitantly with martensite transformation. Compared with conventional hot pressed samples, the HP-DP samples show both better tensile property especially elongation and impact energy absorption ability. The effect of HP-DP parameters on the stability of retained austenite and mechanical property is also discussed. The paper illustrates the promising application potential of the HP-DP process.

  20. Analysis of the Long-Term Corrosion Behavior of X80 Pipeline Steel in Acidic Red Soil Using Electrical Resistance Test Technique

    Directory of Open Access Journals (Sweden)

    Shuaixing Wang

    2015-01-01

    Full Text Available The long-term corrosion rate of X80 steel in an acidic red soil was monitored in situ by using a precise electrical resistance (ER test system. The corrosion characteristics of X80 steel were examined via SEM, EDS, and XRD. The results indicated that the corrosion rate determined from ER test was very similar to that obtained from the mass loss test. The ER test technique made it possible to predict the long-term corrosion rate of steel in soil in situ. The corrosion rate of X80 steel in acidic red soil was about 0.0902 mm/a at 38 weeks, but the corrosion rate was dropped to 0.0226 mm/a after 5 years. The final corrosion product layer was composed mainly of FeOOH, γ-Fe2O3, and FeCO3.

  1. Use of the lambda Red recombinase system to produce recombinant prophages carrying antibiotic resistance genes

    Directory of Open Access Journals (Sweden)

    Jofre Juan

    2006-09-01

    Full Text Available Abstract Background The Red recombinase system of bacteriophage lambda has been used to inactivate chromosomal genes in E. coli K-12 through homologous recombination using linear PCR products. The aim of this study was to induce mutations in the genome of some temperate Shiga toxin encoding bacteriophages. When phage genes are in the prophage state, they behave like chromosomal genes. This enables marker genes, such as antibiotic resistance genes, to be incorporated into the stx gene. Once the phages' lytic cycle is activated, recombinant Shiga toxin converting phages are produced. These phages can transfer the marker genes to the bacteria that they infect and convert. As the Red system's effectiveness decreased when used for our purposes, we had to introduce significant variations to the original method. These modifications included: confirming the stability of the target stx gene increasing the number of cells to be transformed and using a three-step PCR method to produce the amplimer containing the antibiotic resistance gene. Results Seven phages carrying two different antibiotic resistance genes were derived from phages that are directly involved in the pathogenesis of Shiga toxin-producing strains, using this modified protocol. Conclusion This approach facilitates exploration of the transduction processes and is a valuable tool for studying phage-mediated horizontal gene transfer.

  2. Influence of Vanadium and Boron Additions on the Microstructure, Fracture Toughness, and Abrasion Resistance of Martensite-Carbide Composite Cast Steel

    Directory of Open Access Journals (Sweden)

    Waleed Elghazaly

    2016-01-01

    Full Text Available High chromium cast steel alloys are being used extensively in many industrial services where dry or wet abrasion resistance is required. Such steel castings are demanded for cement, stoneware pipes, and earth moving industries. In this research, five steel heats were prepared in 100 kg and one-ton medium frequency induction furnaces and then sand cast in both Y-block and final impact arm spare parts, respectively. Vanadium (0.5–2.5% and boron (120–150 ppm were added to the 18Cr-1.9C-0.5Mo steel heats to examine their effects on the steel microstructure, mechanical properties especially impact, fracture toughness and abrasion resistance. Changes in the phase transformation after heat treatment were examined using inverted, SEM-EDX microscopy; however, the abrasion resistance was measured in dry basis using the real tonnage of crushed and milled stoneware clay to less than 0.1 mm size distribution.

  3. Novel Phagocytosis-Resistant Extended-Spectrum β-Lactamase-Producing Escherichia coli From Keratitis.

    Science.gov (United States)

    Van Tyne, Daria; Ciolino, Joseph B; Wang, Jay; Durand, Marlene L; Gilmore, Michael S

    2016-11-01

    Extended-spectrum β-lactamase (ESBL)-producing Escherichia coli are highly antibiotic resistant, and primary ocular infection by ESBL E coli has rarely been reported. A novel mutation conferring phagocytosis resistance would position a strain well to infect the cornea. A woman with recurrent keratitis presented with a corneal ulcer, which was culture positive for ESBL E coli. Resistant to nearly all other antimicrobials, the infection was treated with amikacin and polymyxin B-trimethoprim, and the ulcer resolved over 3 weeks. Analysis of the E coli genome showed it to belong to multilocus sequence type 131 (ST131). This isolate was found to possess a novel deletion in yrfF, an essential regulator of bacterial capsule synthesis. Disruption of yrfF, which confers mucoidy and increased virulence, has not been previously observed in ESBL E coli from any infection site. This novel variant was experimentally proven to cause the mucoid phenotype, and corresponding resistance to phagocytic killing. Increased resistance to immune clearance in an ESBL E coli lineage already known for its virulence is an unsettling development. This phenotype, which likely positioned it as an unusual cause of corneal ulcer, can be easily recognized in the laboratory, which should help limit its spread.

  4. Multiple Antibiotic-Resistant, Extended Spectrum-β-Lactamase (ESBL-Producing Enterobacteria in Fresh Seafood

    Directory of Open Access Journals (Sweden)

    Asem Sanjit Singh

    2017-08-01

    Full Text Available Members of the family Enterobacteriaceae include several human pathogens that can be acquired through contaminated food and water. In this study, the incidence of extended spectrum β-lactamase (ESBL-producing enterobacteria was investigated in fresh seafood sold in retail markets. The ESBL-positive phenotype was detected in 169 (78.60% isolates, with Escherichia coli being the predominant species (53, followed by Klebsiella oxytoca (27, and K. pneumoniae (23. More than 90% of the isolates were resistant to third generation cephalosporins, cefotaxime, ceftazidime, and cefpodoxime. Sixty-five percent of the isolates were resistant to the monobactam drug aztreonam, 40.82% to ertapenem, and 31.36% to meropenem. Resistance to at least five antibiotics was observed in 38.46% of the isolates. Polymerase Chain Reaction (PCR analysis of ESBL-encoding genes detected blaCTX, blaSHV, and blaTEM genes in 76.92%, 63.3%, and 44.37% of the isolates, respectively. Multiple ESBL genes were detected in majority of the isolates. The recently discovered New Delhi metallo-β-lactamase gene (blaNDM-1 was detected in two ESBL+ isolates. Our study shows that secondary contamination of fresh seafood with enteric bacteria resistant to multiple antibiotics may implicate seafood as a potential carrier of antibiotic resistant bacteria and emphasizes an urgent need to prevent environmental contamination and dissemination of such bacteria.

  5. Multiple Antibiotic-Resistant, Extended Spectrum-β-Lactamase (ESBL)-Producing Enterobacteria in Fresh Seafood

    Science.gov (United States)

    Sanjit Singh, Asem; Lekshmi, Manjusha; Prakasan, Sreepriya; Nayak, Binaya Bhusan; Kumar, Sanath

    2017-01-01

    Members of the family Enterobacteriaceae include several human pathogens that can be acquired through contaminated food and water. In this study, the incidence of extended spectrum β-lactamase (ESBL)-producing enterobacteria was investigated in fresh seafood sold in retail markets. The ESBL-positive phenotype was detected in 169 (78.60%) isolates, with Escherichia coli being the predominant species (53), followed by Klebsiella oxytoca (27), and K. pneumoniae (23). More than 90% of the isolates were resistant to third generation cephalosporins, cefotaxime, ceftazidime, and cefpodoxime. Sixty-five percent of the isolates were resistant to the monobactam drug aztreonam, 40.82% to ertapenem, and 31.36% to meropenem. Resistance to at least five antibiotics was observed in 38.46% of the isolates. Polymerase Chain Reaction (PCR) analysis of ESBL-encoding genes detected blaCTX, blaSHV, and blaTEM genes in 76.92%, 63.3%, and 44.37% of the isolates, respectively. Multiple ESBL genes were detected in majority of the isolates. The recently discovered New Delhi metallo-β-lactamase gene (blaNDM-1) was detected in two ESBL+ isolates. Our study shows that secondary contamination of fresh seafood with enteric bacteria resistant to multiple antibiotics may implicate seafood as a potential carrier of antibiotic resistant bacteria and emphasizes an urgent need to prevent environmental contamination and dissemination of such bacteria. PMID:28867789

  6. Application of laser-produced-plasmas to determination of carbon content in steel; Aplicacion de los plasmas generados por laser a la determinacion de carbono en aceros

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, M.; Aragon, C.; Aguilera, J. A.; Campos, J.

    1994-07-01

    This paper describes an analytical method to determine carbon content in solid and molten steel. It is based on the study of the emission spectrum from a Nd-YAG laser produced plasma. The light emitted from the plasma is focused to the entrance slit of a spectrometer and detected by an OMA III system. For every laser pulse an spectral range of 100 A are recorded. With the use of time-resolved spectroscopy a precision of 1.6 % and a detection limit of 65 ppm of carbon content in steel have been obtained. These values are similar to those of other accurate conventional techniques but using optics fiber and laser excitation it is possible to made sample calibrations in hostile environments. Also, as the analysis are made in real time changes in sample composition can be measured without stopping production processes. (Author) 26 refs.

  7. Delta ferrite-containing austenitic stainless steel resistant to the formation of undesirable phases upon aging

    Science.gov (United States)

    Leitnaker, James M.

    1981-01-01

    Austenitic stainless steel alloys containing delta ferrite, such as are used as weld deposits, are protected against the transformation of delta ferrite to sigma phase during aging by the presence of carbon plus nitrogen in a weight percent 0.015-0.030 times the volume percent ferrite present in the alloy. The formation of chi phase upon aging is controlled by controlling the Mo content.

  8. Rolling-contact fatigue resistance of hard coatings on bearing steels.

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.

    1999-08-18

    Ball- and roller-bearings of the 21st Century are expected to perform better and last longer while operating under more stringent conditions than before. To meet these great expectations, researchers have been constantly exploring new bearing designs or refining existing ones, optimizing microstructure and chemistry of bearing materials, and alternatively, they have been considering the use of thin hard coatings for improved bearing performance and durability. Already, some laboratory tests have demonstrated that hard nitride, carbide (such as TiN, TiC, etc.) and diamondlike carbon (DLC) coatings can be very effective in prolonging the fatigue lives of bearing steels. This paper provides an overview of the recent developments in hard coatings for bearing applications. Previous studies have demonstrated that thin, hard coatings can effectively prolong the fatigue lives of bearing steel substrates. In particular, thinner hard coatings (i.e., 0.2 - 1 {micro}m thick) provide exceptional improvements in the fatigue lives of bearing steel substrates. In contrast, thicker hard coatings suffer micro fracture and delamination when tested under high contact stresses, hence are ineffective and may even have a negative effect on bearing life. Overall, it was concluded that thin hard coatings may offer new possibilities for bearing industry in meeting the performance and durability needs of the 21st Century.

  9. Energy Saving Melting and Revert Reduction (E-SMARRT): Optimization of Heat Treatments on Stainless Steel Castings for Improved Corrosion Resistance and Mechanical Properties

    Energy Technology Data Exchange (ETDEWEB)

    John N. DuPont; Jeffrey D. Farren; Andrew W. Stockdale; Brett M. Leister

    2012-06-30

    It is commonly believed that high alloy steel castings have inferior corrosion resistance to their wrought counterparts as a result of the increased amount of microsegregation remaining in the as-cast structure. Homogenization and dissolution heat treatments are often utilized to reduce or eliminate the residual microsegregation and dissolve the secondary phases. Detailed electron probe microanalysis (EPMA) and light optical microscopy (LOM) were utilized to correlate the amount of homogenization and dissolution present after various thermal treatments with calculated values and with the resultant corrosion resistance of the alloys.The influence of heat treatment time and temperature on the homogenization and dissolution kinetics were investigated using stainless steel alloys CN3MN and CK3MCuN. The influence of heat treatment time and temperature on the impact toughness and corrosion reistance of cast stainless steel alloys CF-3, CF-3M, CF-8, and CF-8M was also investigated.

  10. Strengthening mechanisms and mechanical properties of high interstitial stainless steel for drill collar and its corrosion resistance

    Science.gov (United States)

    Lee, Eunkyung

    Two types (CN66, CN71) of high interstitial stainless steels (HISSs) were investigated for down-hole application in sour gas well environments. Experiments were designed to identify factors that have a significant effect on mechanical properties. The three factors examined in the study were carbon + nitrogen content (0.66 or 0.71 mass %), cooling rate in quenching (air or water), and heat treatment time (2 or 4 hours). The results showed that the cooling rate, C+N content, and the two-factor interaction of these variables have a significant effect on the mechanical properties of HISSs. Based on the statistical analysis results on mechanical properties, extensive analyses were undertaken to understand the strengthening mechanisms of HISSs. Microstructure analysis revealed that a pearlite phase with a high carbide and/or nitride content is dissolved in the matrix by heat treatment at 1,200 ºC which is considered the dissolution to increase the concentration of interstitial elements in steels. The distribution of elements in HISSs was investigated by quantitative mapping using EPMA, which showed that the high carbon concentration (carbide/cementite) area was decreased by increases in both the cooling rate and C+N content. The ferrite volume fraction of each specimen is increased by an increase in cooling rate, because there is insufficient time to form austenite from retained ferrite. The lattice expansion of HISS was investigated by the calculation of lattice parameters under various conditions, and these investigations confirm the solid solution strengthening effect on HISSs. CN66 with heat treatment at fast cooling has the highest wear resistance; a finding that was consistent with hardening mechanisms that occur due to an increased ferrite volume fraction. In addition, precipitates on the surface and the chemical bonding of chromium were investigated. As the amount of CrN bonding increased, the wear resistance also increased. This study also assessed the

  11. Effect of normalizing temperature on the strength of 9Cr–3W–3Co martensitic heat resistant steel

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Peng, E-mail: maxeric@163.com [Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Institute for Special Steels, China Iron and Steel Research Institute, Beijing 100081 (China); Liu, Zhengdong; Bao, Hansheng [Institute for Special Steels, China Iron and Steel Research Institute, Beijing 100081 (China); Weng, Yuqing [Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Liu, Wei, E-mail: liuw@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2014-03-01

    Microstructure and room temperature strength of 9Cr–3W–3Co martensitic heat resistant steel after normalizing at 900–1200 °C for 1 h and then tempering at 750 °C for 1 h have been experimentally investigated using optical microscope (OM), field emission scanning electron microscope (FESEM), electron back-scattered diffraction (EBSD), field emission transmission electron microscope (FETEM) and tensile tests. The results show that with increasing normalizing temperature, the strength of the 9Cr–3W–3Co steel increases from 900 °C to 1000 °C, then keeps almost the same from 1000 °C to 1100 °C and finally increases again from 1100 °C to 1200 °C. The change in the room temperature strength can mainly be attributed to the change in precipitation strengthening. The size and the amount of particles after tempering are mainly due to the re-dissolution of particles during normalization. The higher the normalizing temperature is, the more the coarse particles formed during manufacturing will be re-dissolved, and then the larger the amount of fine particles precipitated during tempering is.

  12. Novel scanning dc-susceptometer for characterization of heat-resistant steels with different states of aging

    Science.gov (United States)

    Pereira, João M. B.; Pacheco, Clara Johanna; Arenas, Monica P.; Araujo, Jefferson F. D. F.; Pereira, Gabriela R.; Bruno, Antonio C.

    2017-11-01

    We have built a scanning dc-susceptometer for magnetic characterization of millimeter-scale samples. Using samples with few millimeter-thick slabs, the setup used is able to apply perpendicularly to the sample uniform dc magnetic fields up to 500 mT. It has a scanning range of 100 mm × 100 mm with micrometer resolution. In the present configuration, the dc-susceptometer is equipped with a pair of commercial Hall effect sensors forming an axial gradiometer. The measured output noise at 6.0 Hz is about 1.0 μTrms/√Hz in an unshielded environment and the magnetic moment sensitivity is 8.8 × 10-11 Am2. In particular, we used it to characterize heat-resistant steels, used as radiant tubes in steam reformer furnaces. We measured the cross-section of tube samples with progressing states of aging from as-cast to state VI. Measuring their susceptibilities, we detected a ferromagnetic layer at the external tube wall on aged samples. We were able to establish a relation between the magnetic response and the microstructural change of the steel.

  13. Inhibition of Staphylococcus aureus biofilm by a copper-bearing 317L-Cu stainless steel and its corrosion resistance.

    Science.gov (United States)

    Sun, Da; Xu, Dake; Yang, Chunguang; Chen, Jia; Shahzad, M Babar; Sun, Ziqing; Zhao, Jinlong; Gu, Tingyue; Yang, Ke; Wang, Guixue

    2016-12-01

    The present study investigated the antibacterial performance, corrosion resistance and surface properties of antibacterial austenitic 317L-Cu stainless steel (317L-Cu SS). After 4.5wt% copper was added to 317L stainless steel (317L SS), the new alloy underwent solid solution and aging heat treatment. Fluorescent staining using 4',6-diamidino-2-phenylindole (DAPI) revealed that the 317L-Cu SS showed strong antibacterial efficacy, achieving a 99% inhibition rate of sessile Staphylococcus aureus cells after 5days. The corrosion data obtained by potentiodynamic polarization curves indicated that in comparison with 317L SS, the pitting potential and corrosion current density of 317L-Cu slightly decreased due to the addition of Cu. The 317L-Cu SS exhibited no cytotoxicity against zebrafish (Danio rerio) embryos. The experimental results in this study demonstrated that the new alloy has potential applications in medical and daily uses. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Selection of appropriate intensity measure for collapse capacity prediction of low to mid-rise steel special moment resisting frames

    Directory of Open Access Journals (Sweden)

    Hamid Reza Jamshidiha

    2017-07-01

    Full Text Available A parameter that quantitatively represents the strength of a ground motion is called Intensity Measure (IM. The value of an IM for a given hazard level is the output parameter of Probabilistic Seismic Hazard Analysis (PSHA which is used in structural seismic analysis. In other words, an intensity measure is a link between PSHA and structural seismic analysis. The main desirable features of an appropriate IM are efficiency and sufficiency. The importance of using an appropriate IM is that the seismic performance assessment of structures can be performed more realistically. In this study, the performance of different scalar IMs to predict the collapse capacity of low to mid-rise steel Special Moment Resisting Frames (SMRFs was evaluated. For this purpose, 3, 6 and 9-story steel SMRFs designed for the SAC project were simulated by OpenSees and the collapse capacity of these structures were determined by using incremental dynamic analyses under 67 far-field ground motion records. After calculating the collapse capacity values by using scalar IMs existing in the technical literature which are classified into structure and non-structure specific IMs, the performance of IMs including efficiency and sufficiency with respect to magnitude, source-to-site distance, and average shear-wave velocity at the upper 30 m was compared.

  15. Effect of Aging on Precipitation Behavior and Pitting Corrosion Resistance of SAF2906 Super Duplex Stainless Steel

    Science.gov (United States)

    Li, Jianchun; Li, Guoping; Liang, Wei; Han, Peide; Wang, Hongxia

    2017-09-01

    The effect of aging temperature and holding time on the precipitation of secondary phases and pitting corrosion resistance of SAF2906 super duplex stainless steel was examined. Chromium nitride and σ phase were observed to preferentially precipitate at the ferrite/austenite interface. An amount of nitrides was also observed within the ferrite grain. The precipitation of chromium nitride occurred before the σ phase. The increase in aging temperature and holding time did not affect the concentration of the nitrides but increased the area fraction of the σ phase at a faster rate. The Cr2N precipitation in SAF2906 is more evident than that of the other duplex stainless steels. The variation tendency of the precipitation concentrations is primarily consistent with the prediction results of Thermo-Calc software. The electrochemical results showed that Cr2N and σ phase significantly reduced the pitting potential. Scanning electron microscope observations revealed that pits appear mainly in regions adjacent to sigma phase and Cr2N.

  16. Seismic load resistance of reinforcing steels in the as delivered condition and after corrosion - relevant material characteristics for performance evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Moersch, Ing. Joerg [Max Aicher Engineering GmbH, Freilassing (Germany)

    2016-10-15

    This type of accelerated corrosion test was used to study the high number of test samples in due time. The corrosion phenomena obtained in salt spray testing deviate significantly from corrosion phenomena (pitting factor) obtained in practical conditions. Salt spray testing represents practical conditions for the more uniform corrosion as a result of a severe carbonation of the concrete and/or for higher chloride contents at the surface of the rebar. At low corrosion current densities the effect of pit depth on residual mechanical performance might be underestimated. Reinforced concrete (r.c.) buildings in seismic areas shall be designed to guarantee enough ductile resources as for example a sufficient rotational capacity to allow for load re-distribution. The rotational capacity is directly dependent on the ductility of the reinforcing steel which is generally expressed as elongation at maximum load (A+g{sub t}) and the hardening ratio (R{sub m}/R{sub e}). A direct testing of the seismic load resistance of reinforcing steels is not part of the construction product standards. Therefore it was decided by European Commission to introduce this performance requirement in the mandate for the revision of EN 10080:2005. In parallel to the standardization process a research project was carried out to deliver the scientific background.

  17. Fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro

    NARCIS (Netherlands)

    Foek, Dave Lie Sam; Yetkiner, Enver; Ozcan, Mutlu

    Objective: To analyze the fatigue resistance, debonding force, and failure type of fiber-reinforced composite, polyethylene ribbon-reinforced, and braided stainless steel wire lingual retainers in vitro. Methods: Roots of human mandibular central incisors were covered with silicone, mimicking the

  18. Thermal conductivity, electrical resistivity, and thermopower of aerospace alloys from 4 to 300 K. 6: Fe-22Cr-13Ni-5Mn stainless steel

    Science.gov (United States)

    Hust, J. G.; Sparks, L. L.

    1971-01-01

    The equipment and techniques for determining the thermal conductivity, electrical resistivity Lorenz ratio, and thermopower characteristics of Fe-22Cr-13Ni-5Mn stainless steel are discussed. The dimensions of the specimen and its preparation are described. The experimental data are represented by arbitrary functions over the entire range and smooth tables are generated from these functions.

  19. Effect of high-manganese cast steel strain hardening on the abrasion wear resistance in a mixture of SiC and water

    Directory of Open Access Journals (Sweden)

    Kalandyk B.

    2013-12-01

    Full Text Available The study attempts to determine the impact of the high-manganese cast steel strain hardening on its abrasion wear resistance in a mixture of SiC and water prepared in accordance with ASTM G75. For tests, the high-manganese cast steel containing 10.7, 17.9 and 20.02% Mn was selected. The results of microstructure examinations and abrasion wear resistance tests carried out on the material in non-hardened condition and after strain hardening with a force of 539.55kN were disclosed. Additionally, the surface of samples after a 16-hour cycle of abrasion tests was examined. Moreover, based on the obtained results, the effect of different contents of Mn in cast steel was studied, mainly in terms of its impact on the abrasion wear resistance. The results obtained on the tested materials were compared with the results obtained on the low-alloyed abrasion wear-resistant cast steel L35GSM.

  20. Effect of the Parameters of Gas-Powder Laser Surfacing on the Structural Characteristics of Reconditioned Surface Layer of Corrosion-Resistant Steels

    Science.gov (United States)

    Krylova, S. E.; Oplesnin, S. P.; Manakov, N. A.; Yasakov, A. S.; Strizhov, A. O.

    2018-01-01

    Results of the developed commercial process for reconditioning the surface of corrosion-resistant steels by the method of laser surfacing are presented. A comparative analysis of the microstructures of the deposited wear-resistant layer, of the zone of fusion with the matrix material and of the diffusion zone after different variants of surfacing is performed. The hardness of the deposited layer is measured and a nondestructive inspection of the latter for the presence of flaws is performed.

  1. A new class of IMP dehydrogenase with a role in self-resistance of mycophenolic acid producing fungi

    DEFF Research Database (Denmark)

    Hansen, Bjarne Gram; Genee, Hans Jasper; Kaas, Christian Schrøder

    2011-01-01

    BACKGROUND: Many secondary metabolites produced by filamentous fungi have potent biological activities, to which the producer organism must be resistant. An example of pharmaceutical interest is mycophenolic acid (MPA), an immunosuppressant molecule produced by several Penicillium species...... not produce MPA. The growth of an A. nidulans strain expressing mpaF was only marginally affected by MPA at concentrations as high as 200 μg/ml. To further substantiate the role of mpaF in MPA resistance, we searched for mpaF orthologs in six MPA producer/non-producer strains from Penicillium subgenus...

  2. Presence of antimicrobial resistance in coliform bacteria from hatching broiler eggs with emphasis on ESBL/AmpC-producing bacteria

    OpenAIRE

    Mezhoud, Halima; Chantziaras, Ilias; Iguer-Ouada, M; N. Moula; Garmyn, An; Martel, An; Touati, A.; Smet, Annemieke; Haesebrouck, Freddy; Boyen, Filip

    2016-01-01

    Antimicrobial resistance is recognized as one of the most important global health challenges. Broilers are an important reservoir of antimicrobial-resistant bacteria in general and, more particularly, extended-spectrum beta-lactamases (ESBL)/AmpC-producing Enterobacteriaceae. Since contamination of 1-day-old chicks is a potential risk factor for the introduction of antimicrobial-resistant Enterobacteriaceae in the broiler production chain, the presence of antimicrobial-resistant coliform bact...

  3. Effect of molybdenum on wear resistance of Cr-Nb hard-faced S355JR steel

    Energy Technology Data Exchange (ETDEWEB)

    Thongchitrugsa, Nut; Chianpairot, Amnuaysak; Hartung, Fritz; Lothongkum, Gobboon [Chulalongkorn Univ., Bangkok (Thailand). Dept. of Metallurgical Engineering

    2014-03-01

    The effect of Mo on the abrasive wear resistance of (20-23)Cr-(7-8)Nb hard-faced S355JR steel by shielded metal arc welding (SMAW) was studied. Four types of flux, consisting of fixed Cr and Nb but varying Mo contents, coated on hard-facing electrode were used. Microstructure, micro hardness, and abrasive wear resistance of the hard-faced surface were investigated by ASTM G65 D procedure. The original microstructures consist of the primary coarse and eutectic carbides. Mo affects morphology of carbides by decreasing primary carbide size. When Mo content in the hard-faced surface was up to 6.43 wt.-%, the highest abrasive wear resistance and micro hardness were obtained. The decrease of primary carbide size is attributed to the increased nucleation induced by Mo addition. Network structure was observed when the Mo content reaches 10.19 wt.-%. The main mechanisms of wear are micro-cutting and carbide pulling out. (orig.)

  4. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-11-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  5. Assessment of Stress Corrosion Cracking Resistance of Activated Tungsten Inert Gas-Welded Duplex Stainless Steel Joints

    Science.gov (United States)

    Alwin, B.; Lakshminarayanan, A. K.; Vasudevan, M.; Vasantharaja, P.

    2017-12-01

    The stress corrosion cracking behavior of duplex stainless steel (DSS) weld joint largely depends on the ferrite-austenite phase microstructure balance. This phase balance is decided by the welding process used, heat input, welding conditions and the weld metal chemistry. In this investigation, the influence of activated tungsten inert gas (ATIG) and tungsten inert gas (TIG) welding processes on the stress corrosion cracking (SCC) resistance of DSS joints was evaluated and compared. Boiling magnesium chloride (45 wt.%) environment maintained at 155 °C was used. The microstructure and ferrite content of different weld zones are correlated with the outcome of sustained load, SCC test. Irrespective of the welding processes used, SCC resistance of weld joints was inferior to that of the base metal. However, ATIG weld joint exhibited superior resistance to SCC than the TIG weld joint. The crack initiation and final failure were in the weld metal for the ATIG weld joint; they were in the heat-affected zone for the TIG weld joint.

  6. Hydrogen diffusion and effect on degradation in welded microstructures of creep-resistant low-alloyed steels

    Energy Technology Data Exchange (ETDEWEB)

    Rhode, Michael

    2016-04-04

    The main challenge for the future is to further increase the power plant thermal efficiency independent of the type of power plant concept, i.e. fossil-fired or nuclear power plant, where the material selection can directly affect reduction of CO{sub 2} emissions. In power plant design, welding is the most applied manufacturing technique in component construction. The necessary weld heat input causes metallurgical changes and phase transitions in the heat affected zone (HAZ) of the base materials and in the deposited weld metal. The weld joint can absorb hydrogen during welding or in later service - This absorption can cause degradation of mechanical properties of the materials, and in certain loading conditions, hydrogen-assisted cold cracks can occur. This cracking phenomenon can appear time delayed due to the temperature dependency of the hydrogen diffusion and the presence of a ''critical'' hydrogen concentration. Additionally, each specific weld microstructure shows a certain hydrogen diffusion and solubility that contribute to susceptibility of the cracking phenomenon. Therefore hydrogen cannot be neglected as possible failure effect, which was identified recently in the case of T24 creep-resistant tube-to-tube weld joints. It is necessary to identify and assess the hydrogen effect in weld joints of low-alloyed steel grades for to improve further early detection of possible failures. For each specific weld joint microstructure, it is necessary to separate the interdependencies between mechanical load and the hydrogen concentration. The diffusivity and solubility must be considered to identify hydrogen quantities in the material at any given time. In this case, the effects of mechanical loading were dealt with independently. For the characterization of the mechanical properties, hydrogen charged tensile specimens were investigated for the base materials and thermally simulated HAZ microstructures. The hydrogen diffusion was characterized

  7. Corrosion Resistance, EIS and Wettability of the Implants Made of 316 LVM Steel Used in Chest Deformation Treatment

    Directory of Open Access Journals (Sweden)

    Kajzer A.

    2016-06-01

    Full Text Available The paper presents the influence of mechanical surface damage on the physicochemical properties of plates after implantation made of CrNiMo stainless steel, used in the treatment of anterior surface deformity of the chest. Analysis of the data allowed us to investigate the effect of implant design and condition of their surface on the results of chest deformation treatment. Results of electrochemical, impedance and surface wettability tests and SEM observations were compared with clinical observations. When removing the plates we found only slight inflammatory-periosteal reactions. On the basis of obtained results, it can be stated that plates, in spite of mechanical damage of the surface, were characterized by good corrosion resistance, a fact which is confirmed by the results of clinical evaluation.

  8. Microstructural evolution and change in hardness of S30432 heat-resistant steel during creep at 650 c

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, L.H.; Zhang, Y.J. [School of Materials Science and Engineering, Shanghai University (China); Wang, Q.J.; Xu, S.Q. [Baoshan Iron and Steel Co., Ltd. Shanghai (China)

    2010-04-15

    The microstructural evolution of S30432 heat-resistant steel during creep at 650 C and its effect on the change in hardness was investigated. The change of hardness during creep of S30432 at 650 C can be divided into three stages. These are related to the precipitation and coarsening of {epsilon}-Cu and M{sub 23}C{sub 6} carbides, decrease in the number of twins and increase in grain size. The precipitation of {epsilon}-Cu dominantly contributes to the significant hardening at stage I, and the coarsening of {epsilon}-Cu is the key factor to decrease the hardness at stage II. At stage III, the hardness hardly changes since the microstructure of S30432 tends to be stable in the long-term creep range. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Actinomycetes of Orthosipon stamineus rhizosphere as producer of antibacterial compound against multidrug resistant bacteria

    Science.gov (United States)

    Rante, H.; Yulianty, R.; Usmar; Djide, N.; Subehan; Burhamzah, R.; Prasad, M. B.

    2017-11-01

    The increasing case of antibiotic resistence has become an important problem to be faced in treating the infection diseases. The diversities of microbia, especially actinomycetes bacteria which originated from rizosphere soil of medicinal plant, has opened a chance for discovering the metabolites which can be used in solving the antibiotic resistant pathogenic bacteria problems. The aim of this research was to isolate the actinobacteria originated from medicinal plant rizosphere of Orthosipon stamineus as the producer of anti-multidrug resistances bacteria compounds. Three isolates of actinomycetes has been isolated from Orthosipon stamineus rhizosphere named KC3-1, KC3-2 and KC3-3. One isolate (KC3-3) showed big activity in inhibiting the test microbes by antagonistic test of actinomycetes isolates against Staphylococcus aureus and Eschericia coli antibiotic resistant bacteria. Furthermore, the KC3-3 isolate was fermented in Starch Nitrate Broth (SNB) medium for 14 days. The supernatant and the biomass of the fermentation yield were separated. The supernatant were extracted using ethyl acetate as the solvent and the biomass were extracted using methanol. The antibacterial activity test of ethyl acetate and methanol extract revealed that the extracts can inhibit the bacteria test up to 5% concentration. The ethyl acetate and methanol extracts can inhibit the bacteria test up to 5% concentration.

  10. Synergistic activity of biocides and antibiotics on resistant bacteria from organically produced foods.

    Science.gov (United States)

    Fernández Fuentes, Miguel Angel; Abriouel, Hikmate; Gadea, Rebeca; Pérez Pulido, Rubén; Gálvez, Antonio; Ortega, Elena

    2014-10-01

    Synergism between biocides and antibiotics was investigated in 20 biocide and antibiotic-resistant bacterial strains that were previously isolated from organically produced foods, according to their antimicrobial resistance profiles. Most of the antibiotic/biocide combinations yielded synergistic interactions, reducing the inhibitory concentrations of biocides and antibiotics by 4- to 16-fold. Among enterococci, synergism with biocides was detected for amoxicillin (AM), cefuroxime (CX), erythromycin (EM), ciprofloxacin (CP), and trimethoprim/sulphametoxazol (T/S). Among staphylococci, interactions were synergistic (AM) and either synergistic or indifferent (CX and EM, depending on biocide). Among the three methicillin-resistant Staphylococcus aureus clinical strains included in the study, the combinations of methicillin and triclosan or hexachlorophene acted synergistically in all strains, but interactions were either synergistic or indifferent for the other biocides, depending on the strain. All combinations tested were synergistic for Lactobacillus (AM, CX, EM, and CP) and Micrococcus (AM, EM). In Salmonella, interactions were indifferent (AM, CX, EM, and CP) or synergistic (T/S). Synergism with biocides was also detected in Klebsiella isolates (AM, CX, and T/S), Enterobacter sp. (AM, CX, EM, and T/S), Pantoea (AM, CX, EM, CP, and T/S), and Chryseobacterium sp. (EM). These results suggest that combinations of biocides and antibiotics may open new possibilities to combat antimicrobial resistance.

  11. Numerical and Physical Study on a Cylindrical Tundish Design to Produce a Swirling Flow in the SEN During Continuous Casting of Steel

    Science.gov (United States)

    Ni, Peiyuan; Wang, Dongxing; Jonsson, Lage Tord Ingemar; Ersson, Mikael; Zhang, Ting-an; Jönsson, Pär Göran

    2017-10-01

    A new tundish design was investigated using both water model experiments and numerical simulations. The results show that the Reynolds Stress Model simulation results agree well with the Particle Image Velocimetry-measured results for water model experiments. A strong swirling flow in the Submerged Entry Nozzle (SEN) of the new tundish was successfully obtained, and the tangential velocity in the region near SEN inlet could reach a value of around 3.1 m/s. A high value of the shear stress was found to exist on the SEN wall, due to the strong swirling flow inside the SEN. This large shear stress leads to the dissipation of the rotational momentum of the steel flow. Thus, the maximum tangential velocity of the steel flow decreases from 3.1 m/s at around the SEN inlet to 2.2 m/s at a location close to the SEN outlet. In addition, the near-wall region has a high pressure, which is larger than the atmospheric pressure, due to the centrifugal effect. The calculated swirl number, with the value of around 1.6 at SEN inlet, illustrates that the current design can produce a similar strong swirling flow compared to the swirl blade method and the electromagnetic stirring method, while this is obtained by simply changing the steel flow path in tundish instead of using additional device to influence the flow.

  12. Phase composition and crack resistance of alloy boride layers on steel

    Science.gov (United States)

    Kholin, A. S.

    1999-04-01

    Alloying of boride layers on steel changes their phase composition, morphology, and structure. Chromium and manganese diminish the fraction of the eutectic in the layer. B-Cr and B-Mn coats do not contain monoborides. B, B-Mo, and B-Mo-W coats consist of two layers, i.e., monoborides and diborides. The other studied coats are represented by a diboride with inclusions of a monoboride. Molybdenum intensifies the texture of the FeB boride as compared with a purely boride layer; the other elements weaken it considerably.

  13. Effect of carbides on erosion resistance of 23-8-N steel

    Indian Academy of Sciences (India)

    ment in erosion resistance can be attributed to major changes in microstructure and the mechanical properties. The sig- nificant change in the microstructure is associated with the dissolution of carbides. In alloy system, the highest ero- sion resistance has been reported to be obtained either in the solution treated condition ...

  14. Effect of liquid phase sintering on the mechanical properties and corrosion resistance of infiltrated austenitic stainless steel; Efeito da sinterizacao com fase liquida sobre as propriedades mecanicas e resistencia a corrosao do aco inoxidavel austenitico infiltrado

    Energy Technology Data Exchange (ETDEWEB)

    Machado, Cristine F. [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Programa de Pos-graduacao em Engenharia Metalurgica e dos Materiais; Matos Dias, Arao de; Schaeffer, Lirio [Rio Grande do Sul Univ., Porto Alegre, RS (Brazil). Centro de Tecnologia. Lab. de Metalurgia do Po

    1996-12-31

    First, this work presents some considerations on the properties and corrosion resistance of the stainless steels and its relation with porosity. The infiltration technique of copper into compacted steels is presented as an efficacy alternative to improve both mechanical properties and corrosion resistance. In experimental development, it was carried out mechanical tests with stainless steel AISI 316 L to ratify the copper infiltration effects on the yield stress of the material, and corrosion tests in salt spray. The results confirm a considerable improvement in properties on the whole to infiltrated stainless steel. (author) 18 refs., 8 figs., 4 tabs.

  15. Improved Phenotype-Based Definition for Identifying Carbapenemase Producers among Carbapenem-Resistant Enterobacteriaceae.

    Science.gov (United States)

    Chea, Nora; Bulens, Sandra N; Kongphet-Tran, Thiphasone; Lynfield, Ruth; Shaw, Kristin M; Vagnone, Paula Snippes; Kainer, Marion A; Muleta, Daniel B; Wilson, Lucy; Vaeth, Elisabeth; Dumyati, Ghinwa; Concannon, Cathleen; Phipps, Erin C; Culbreath, Karissa; Janelle, Sarah J; Bamberg, Wendy M; Guh, Alice Y; Limbago, Brandi; Kallen, Alexander J

    2015-09-01

    Preventing transmission of carbapenemase-producing, carbapenem-resistant Enterobacteriaceae (CP-CRE) is a public health priority. A phenotype-based definition that reliably identifies CP-CRE while minimizing misclassification of non-CP-CRE could help prevention efforts. To assess possible definitions, we evaluated enterobacterial isolates that had been tested and deemed nonsusceptible to >1 carbapenem at US Emerging Infections Program sites. We determined the number of non-CP isolates that met (false positives) and CP isolates that did not meet (false negatives) the Centers for Disease Control and Prevention CRE definition in use during our study: 30% (94/312) of CRE had carbapenemase genes, and 21% (14/67) of Klebsiella pneumoniae carbapenemase-producing Klebsiella isolates had been misclassified as non-CP. A new definition requiring resistance to 1 carbapenem rarely missed CP strains, but 55% of results were false positive; adding the modified Hodge test to the definition decreased false positives to 12%. This definition should be considered for use in carbapenemase-producing CRE surveillance and prevention.

  16. Outbreak of Imipenemase-1-Producing Carbapenem-Resistant in an Intensive Care Unit

    Directory of Open Access Journals (Sweden)

    Jin Young Lee

    2017-02-01

    Full Text Available Background Carbapenem-resistant Enterobacteriaceae (CRE with acquired metallo β-lactamase (MBL resistance have been increasingly reported worldwide and associated with significant mortality and morbidity. Here, an outbreak of genetically related strains of Klebsiella pneumoniae producing the imipenemase (IMP-1 MBL in a medical intensive care unit (MICU in Korea is reported. Methods Since isolating carbapenem-resistant K. pneumoniae (CRKP at the MICU of the hospital on August 10, 2011, surveillance cultures for CRE in 31 hospitalized patients were performed from August to September 2011. Carbapenem resistance was determined based on the disk diffusion method outlined in the Clinical and Laboratory Standards Institute guidelines. Polymerase chain reaction (PCR was performed for genes coding for β-lactamase. Associations among isolates were assessed via pulsed-field gel electrophoresis (PFGE. In addition, a surveillance study of environmental cultures and health-care workers (HCWs was conducted in the MICU during the same time frame. Results During the study period, non-duplicated CRKP specimens were discovered in four patients in the MICU, suggestive of an outbreak. On August 10, 2011, CRKP was isolated from the sputum of a 79-year-old male patient who was admitted to the MICU. A surveillance study to detect additional CRE carriers by rectal swab revealed an additional three CRKP isolates. PCR and sequencing of the four isolates identified the presence of the IMP-1 gene. In addition, PFGE showed that the four isolated strains were genetically related. CRE was not identified in specimens taken from the hands of HCWs or other environmental sources during surveillance following the outbreak. Transmission of the carbapenemase-producing Enterobacteriaceae strain was controlled by isolation of the patients and strict contact precautions. Conclusions This study shows that rapid and systemic detection of CRE and strict infection controls are important

  17. Lethality of chlorine, chlorine dioxide, and a commercial produce sanitizer to Bacillus cereus and Pseudomonas in a liquid detergent, on stainless steel, and in biofilm.

    Science.gov (United States)

    Kreske, Audrey C; Ryu, Jee-Hoon; Pettigrew, Charles A; Beuchat, Larry R

    2006-11-01

    Many factors that are not fully understood may influence the effectiveness of sanitizer treatments for eliminating pathogens and spoilage microorganisms in food or detergent residues or in biofilms on food contact surfaces. This study was done to determine the sensitivities of Pseudomonas cells and Bacillus cereus cells and spores suspended in a liquid dishwashing detergent and inoculated onto the surface of stainless steel to treatment with chlorine, chlorine dioxide, and a commercial produce sanitizer (Fit). Cells and spores were incubated in a liquid dishwashing detergent for 16 to 18 h before treatment with sanitizers. At 50 microg/ml, chlorine dioxide killed a significantly higher number of Pseudomonas cells (3.82 log CFU/ml) than did chlorine (a reduction of 1.34 log CFU/ml). Stainless steel coupons were spot inoculated with Pseudomonas cells and B. cereus cells and spores, with water and 5% horse serum as carriers. Chlorine was more effective than chlorine dioxide in killing cells and spores of B. cereus suspended in horse serum. B. cereus biofilm on stainless steel coupons that were treated with chlorine dioxide or chlorine at 200 microg/ml had total population reductions (vegetative cells plus spores) of > or = 4.42 log CFU per coupon; the number of spores was reduced by > or = 3.80 log CFU per coupon. Fit (0.5%) was ineffective for killing spot-inoculated B. cereus and B. cereus in biofilm, but treatment with mixtures of Fit and chlorine dioxide caused greater reductions than did treatment with chlorine dioxide alone. In contrast, when chlorine was combined with Fit, the lethality of chlorine was completely lost. This study provides information on the survival and sanitizer sensitivity of Pseudomonas and B. cereus in a liquid dishwashing detergent, on the surface of stainless steel, and in a biofilm. This information will be useful for developing more effective strategies for cleaning and sanitizing contact surfaces in food preparation and processing

  18. The influence of remelting parameters of the electric arc and conventional tempering on the tribological resistance of high speed steel HS 6-5-2

    Directory of Open Access Journals (Sweden)

    A. Dziedzic

    2011-07-01

    Full Text Available The present thesis depicts the results of the research of tribological high speed steel HS 6-5-2 remelted with the electric arc. Steel was remelted with different parameters. The amperage of electric arc was changed, the scanning speed was changed and the single, overlapping remeltings were used. There was also the influence of conventional tempering defined, which was conducted after remelting on the tribological resistance of hardened steel. For the previously mentioned processing variants, the intensity of tribological wear was defined and the linear wear were presented, and the friction coefficients. The type of tribological wear was also given, present during the friction, technically dry, of the hardened steel. The lower intensity of tribological wear was received for the single remelting by electric arc of 50 and 70A. Using the overlapping remeltings for the strengening of the surface layer of the high speed steel HS 6-5-2 causes the increase of the intensity of tribological wear in comparison to the steel with the single remelting. The conventional tempering leads to the decrease of the intensity of tribological wear.

  19. Low-load resistance training with low relative pressure produces muscular changes similar to high-load resistance training.

    Science.gov (United States)

    Kim, Daeyeol; Loenneke, Jeremy P; Ye, Xin; Bemben, Debra A; Beck, Travis W; Larson, Rebecca D; Bemben, Michael G

    2017-12-01

    This study compares the acute and chronic response of high-load resistance training (HL) to low-load resistance training with low blood flow restriction (LL-BFR) pressure. Participants completed elbow flexion with either HL or LL-BFR or nonexercise. In the chronic study, participants in the HL and LL-BFR groups were trained for 8 weeks to determine differences in muscle size and strength. The acute study examined the changes in pretesting/posttesting (Pre/Post) torque, muscle swelling, and blood lactate. In the chronic study, similar changes in muscle size and strength were observed for both HL and LL-BFR. In the acute study, Pre/Post changes in the torque, muscle swelling, and blood lactate were similar between HL and LL-BFR. Our findings indicate that pressure as low as 50% arterial occlusion can produce similar changes in muscle mass and strength compared with traditional HL. Muscle Nerve 56: E126-E133, 2017. © 2017 Wiley Periodicals, Inc.

  20. Antibiotic Resistance Pattern of Extended-Spectrum Beta-Lactamases-Producing Klebsiella pneumoniae Clinical Isolates from Zahedan, Southeast Iran

    Directory of Open Access Journals (Sweden)

    Shahram Shahraki-Zahedani

    2016-10-01

    Full Text Available Background Resistance to various classes of antibiotics is common among extended-spectrum beta-lactamases (ESBLs-producing bacteria. Objectives To determine the antibiotic resistance pattern of ESBLs-producing K. pneumoniae clinical isolates from Zahedan. Methods In this sectional-descriptive study, susceptibility of 51 ESBLs-producing K. pneumoniae isolates to 18 antimicrobial agents was determined. Results All isolates were resistant to cefotaxime, cefpodoxime and amoxicillin as well as susceptible to colistin sulfate. Also, most isolates were resistant to trimethoprim/sulfamethoxazole and aztreonam. Conclusions Our findings demonstrated that the rate of resistance to beta-lactams, sulfonamides, tetracyclines, aminoglycosides and fluoroquinolones in ESBLs-producing K. pneumoniae isolates is high in Zahedan.

  1. Study of the Corrosion Resistance of Austenitic Stainless Steels during Conversion of Waste to Biofuel.

    Science.gov (United States)

    Cabrini, Marina; Lorenzi, Sergio; Pastore, Tommaso; Pellegrini, Simone; Burattini, Mauro; Miglio, Roberta

    2017-03-22

    The paper deals with the corrosion behavior of stainless steels as candidate materials for biofuel production plants by liquefaction process of the sorted organic fraction of municipal solid waste. Corrosion tests were carried out on AISI 316L and AISI 304L stainless steels at 250 °C in a batch reactor during conversion of raw material to bio-oil (biofuel precursor), by exposing specimens either to water/oil phase or humid gas phase. General corrosion rate was measured by weight loss tests. The susceptibility to stress corrosion cracking was evaluated by means of U-bend specimens and slow stress rate tests at 10-6 or 10-5 s-1 strain rate. After tests, scanning electron microscope analysis was carried out to detect cracks and localized attacks. The results are discussed in relation with exposure conditions. They show very low corrosion rates strictly dependent upon time and temperature. No stress corrosion cracking was observed on U-bend specimens, under constant loading. Small cracks confined in the necking cone of specimens prove that stress corrosion cracking only occurred during slow strain rate tests at stresses exceeding the yield strength.

  2. Changes in the state of heat-resistant steel induced by repeated hot deformation

    Science.gov (United States)

    Lyubimova, Lyudmila L.; Fisenko, Roman N.; Tashlykov, Alexander A.; Tabakaev, Roman B.

    2018-01-01

    This work deals with the problems of structural regeneration by thermal restoration treatment (TRT). These include the lack of a structural sign showing that TRT is possible, a consensus on TRT modes, the data on the necessary relaxation depth of residual stresses, or criteria of structural restoration. Performing a TRT without solving these problems may deteriorate the properties of steel or even accelerate its destruction. With this in view, the purpose of this work is to determine experimentally how the residual stress state changes under thermal and mechanical loads in order to specify the signs of the restoration of structure and structural stability. The object of this research is unused 12Cr1MoV steel that has been aged naturally for 13 years. Using X-ray dosimetry with X-ray spectral analysis, we study the distribution of internal residual stresses of the first kind during the repeated hot deformation. After repeated thermal deformation, the sample under study transforms from a viscoelastic Maxwell material into a Kelvin-Voigt material, which facilitates structural stabilization. A sign of this is the relaxation limit increase, prevention of continuous decay of an α-solid solution of iron and restoration of the lattice parameter.

  3. Cytokines produced by susceptible and resistant mice in the course of Paracoccidioides brasiliensis infection

    Directory of Open Access Journals (Sweden)

    Calich V.L.G.

    1998-01-01

    Full Text Available Paracoccidioidomycosis (PCM is the most prevalent deep mycosis in Latin America and presents a wide spectrum of clinical manifestations. We established a genetically controlled murine model of PCM, where A/Sn mice develop an infection which mimics the benign disease (immune responses which favor cellular immunity and B10.A animals present the progressive disseminated form of PCM (preferential activation of B cells and impairment of cellular immune responses. To understand the immunoregulatory phenomena associated with resistance and susceptibility in experimental PCM, A/Sn and B10.A mice were studied regarding antigen-elicited secretion of monokines (TNF-a and TGF-ß and type-1 (IL-2 and IFN-g and type-2 (IL-4,5,10 cytokines. Total lymph node cells from resistant mice infected ip with P. brasiliensis produced early and sustained levels of IFN-g and IL-2; type-2 cytokines (IL-4 and IL-5 started to appear 8 weeks after infection. In contrast, susceptible mice produced low levels of IFN-g concomitant with significant levels of IL-5 and IL-10 early in the infection. In the chronic phase of the disease, susceptible animals presented a transitory secretion of IL-2, and IL-4. In the pulmonary infection IL-4, IL-5 and IL-10 were preferentially detected in the lung cells washings of susceptible animals. After in vitro challenge with fungal antigens, normal peritoneal macrophages from B10.A mice secreted high levels of TGF-ß and low levels of TNF-a. In contrast, macrophages from A/Sn animals released high levels of TNF-a associated with a small production of TGF-ß. The in vivo depletion of IFN-g not only abrogated the resistance of A/Sn mice but also diminished the relative resistance of B10.A animals. The in vivo depletion of IL-4 did not alter the disease outcome, whereas administration of rIL-12 significantly enhanced resistance in susceptible animals. Taken together, these results suggest that an early secretion of high levels of TNF-a and IFN

  4. Corrosion Behavior of Austenitic and Duplex Stainless Steels in Lithium Bromide

    Directory of Open Access Journals (Sweden)

    Ayo Samuel AFOLABI

    2009-07-01

    Full Text Available The corrosion behavior of austenitic and duplex stainless steels in various concentrations of lithium, bromide solution was investigated by using the conventional weight loss measurement method. The results obtained show that corrosion of these steels occurred due to the aggressive bromide ion in the medium. Duplex stainless steel shows a greater resistance to corrosion than austenitic stainless steel in the medium. This was attributed to equal volume proportion of ferrite and austenite in the structure of duplex stainless steel coupled with higher content of chromium in its composition. Both steels produced electrochemical noise at increased concentrations of lithium bromide due to continuous film breakdown and repair caused by reduction in medium concentration by the alkaline corrosion product while surface passivity observed in duplex stainless steel is attributed to film stability on this steel.

  5. Emergence of carbapenem-resistant OXA-48 carbapenemase-producing Enterobacteriaceae in Tunisia.

    Science.gov (United States)

    Saïdani, M; Hammami, S; Kammoun, A; Slim, A; Boutiba-Ben Boubaker, I

    2012-12-01

    We screened 21 extended spectrum β-lactamase-producing Enterobacteriaceae with reduced susceptibility to carbapenems for carbapenemase production. Five strains (four Klebsiella pneumoniae and one Citrobacter freundii) showed carbapenemase production, which was identified as OXA-48. The bla(OXA-48) gene was detected on ~54 kb plasmids belonging to IncA/C in one case. Two isolates harboured IS1999, which is involved in bla(OXA-48) mobilization. Carbapenem resistance in enterobacteria should be regarded as an emerging clinical problem in our hospital and necessitates rigorous surveillance in order to limit its spread.

  6. The role of alloy composition, environment and stresses for the oxidation resistance of modern 9% Cr steels for fossil power stations

    Directory of Open Access Journals (Sweden)

    M. Schütze

    2004-03-01

    Full Text Available In recent years a new group of ferritic-martensitic chromium steels for the use in fossil power stations has been developed with chromium contents between 9 and 12%. Typical representatives of these steels are P91, E911 and Nf616, which are nowadays widely used in the more advanced power plants. In the development phase the focus was on the mechanical properties of these steels but when taking them to practical operation conditions it turned out that much of the life-time of the materials and components is determined by their oxidation properties. Oxidation resistance is first of all a function of alloy composition. For the steels of this group it is chromium, silicon, manganese and molybdenum that decide their oxidation performance and since the contents especially of the four elements can be significantly different for the different steels there can be clear differences in oxidation behaviour. One of the most important issues from this point of view is how the concentrations of these elements change in the metal subsurface zone during operation/oxidation since if their level drops below a critical level oxidation resistance of the steels will be lost. In the work to be reported the influence of alloy composition and metal subsurface zone concentration as a function of oxidation time up to 10000 h was investigated in dry air and air up to 10% water vapour at 650 °C. The investigations comprised several of the advanced commercial 9% Cr steels including P91, E911, Nf616 and six laboratory melts of Nf616 with different amounts of silicon. As the results of the investigations show humidity, which is omnipresent in combustion environments, can dramatically accelerate oxidation. Silicon as an alloying element reduces the detrimental effect of water vapour significantly while molybdenum has a negative effect. The effects of the key alloying elements in these steels was quantified for conditions with and without water vapour in the environment

  7. [Assessment of occupational exposure of welders based on determination of fumes and their components produced during stainless steel welding].

    Science.gov (United States)

    Stanisławska, Magdalena; Janasik, Beata; Trzcinka-Ochocka, Małgorzata

    2011-01-01

    Occupational exposure to welding fumes is a known health hazard. The aim of this study was to determine concentrations of welding fumes components such as: iron, manganese, nickel and chromium (including chromium speciation) to assess exposure of stainless steel welders. The survey covered 14 workers of two metallurgic plants engaged in welding stainless steel (18% Cr and 8% Ni) by different techniques: manual metal arc (MMA), metal inert gas (MIG) and tungsten inert gas (TIG). Personal air samples were collected in the welders' breathing zone over a period of about 6-7 h (dust was collected on a membrane and glass filter) to determine time weighted average (TWA) concentration of welding fumes and its components. The concentrations of welding fumes (total particulate) were determined with use of the gravimetric method. Concentrations and welding fume components, such as: iron, manganese, nickel and chromium were determined by ICP-MS technique. The total hexavalent chromium was analyzed by applying the spectrophotometry method according to NIOSH. The water-soluble chromium species were analyzed by HPLC-ICP-MS. Time weighted average concentrations of the welding fumes and its components at the worker's breathing zone were (mg/m3): dust, 0.14-10.7; iron, 0.004-2.9; manganese, 0.001-1.12; nickel, < 0.001-0.2; and chromium <0.002-0.85 (mainly Cr(III) and insoluble Cr(VI)). The maximum admissible limits for workplace pollutants (TLV-TWA) were exceeded for manganese and for insoluble chromium Cr (VI). For Cr (III) the limit was exceeded in individual cases. The assessment of the workers' occupational exposure, based on the determined time weighted average (TWA) of fumes and their components, shows that the stainless steel welders worked in conditions harmful to their health owing to the significantly exceeded maximum admissible limits for manganese and the exceeded TLV value for insoluble chromium (VI).

  8. Oxidation behavior and area specific resistance of La, Cu and B alloyed Fe-22Cr ferritic steels for solid oxide fuel cell interconnects

    Science.gov (United States)

    Swaminathan, Srinivasan; Ko, Yoon Seok; Lee, Young-Su; Kim, Dong-Ik

    2017-11-01

    Two Fe-22 wt% Cr ferritic stainless steels containing varying concentrations of La (0.14 or 0.52 wt%), Cu (0.17 or 1.74 wt%) and B (48 or 109 ppm) are investigated with respect to oxidation behavior and high temperature area specific resistance (ASR) of the surface oxide scales. To determine the oxidation resistance of developed steels, continuous isothermal oxidation is carried out at 800 °C in air, for 2000 h, and their thermally grown oxide scale is characterized using dynamic SIMS, SEM/EDX, XRD and GI-XRD techniques. To assess their electrical performance, the ASR measurement by four-point probe method is conducted at 800 °C in air, for 400 h. In higher La content steel, the La-oxides at the scale/alloy interface promotes the oxygen transport which resulted in sub-surface oxidation of Mn, Cr, Ti and Al. Moreover, the inward growth of oxides contributes to increase of Fe-Cr alloy protrusions within the scale, which reduced the ASR. In contrast, sub-surface oxidation is reduced in high Cu-alloyed steel by segregated Cu at the scale/alloy interface. Thus, addition of Cu is effective to oxidation resistance and also to better electrical performance. However, no obvious impact of B on the scale sequence and/or ASR is observed.

  9. Standard test methods for pitting and crevice corrosion resistance of stainless steels and related alloys by use of ferric Chloride solution

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 These test methods cover procedures for the determination of the resistance of stainless steels and related alloys to pitting and crevice corrosion (see Terminology G 15) when exposed to oxidizing chloride environments. Six procedures are described and identified as Methods A, B, C, D, E, and F. 1.1.1 Method A—Ferric chloride pitting test. 1.1.2 Method B—Ferric chloride crevice test. 1.1.3 Method C—Critical pitting temperature test for nickel-base and chromium-bearing alloys. 1.1.4 Method D—Critical crevice temperature test for nickel-base and chromium-bearing alloys. 1.1.5 Method E—Critical pitting temperature test for stainless steels. 1.1.6 Method F—Critical crevice temperature test for stainless steels. 1.2 Method A is designed to determine the relative pitting resistance of stainless steels and nickel-base, chromium-bearing alloys, whereas Method B can be used for determining both the pitting and crevice corrosion resistance of these alloys. Methods C, D, E and F allow for a rankin...

  10. Corrosion Resistance and Mechanical Properties of TIG and A-TIG Welded Joints of Lean Duplex Stainless Steel S82441 / 1.4662

    Directory of Open Access Journals (Sweden)

    Brytan Z.

    2016-06-01

    Full Text Available This paper presents results of pitting corrosion resistance of TIG (autogenous and with filler metal and A-TIG welded lean duplex stainless steel S82441/1.4662 evaluated according to ASTM G48 method, where autogenous TIG welding process was applied using different amounts of heat input and shielding gases like pure Ar and Ar+N2 and Ar+He mixtures. The results of pitting corrosion resistance of the welded joints of lean duplex stainless steel S82441 were studied in as weld conditions and after different mechanical surface finish treatments. The results of the critical pitting temperature (CPT determined according to ASTM G48 at temperatures of 15, 25 and 35°C were presented. Three different surface treatment after welding were applied: etching, milling, brushing + etching. The influence of post weld surface treatment was studied in respect to the pitting corrosion resistance, basing on CPT temperature.

  11. Corrosion resistance of Cu-Al coatings produced by thermal spray

    Directory of Open Access Journals (Sweden)

    Laura Marcela Dimaté Castellanos

    2012-01-01

    Full Text Available Many components in the shipbuilding industry are made of copper-based alloys. These pieces tend to break due to corrosion generated by a marine environment; such components can be salvaged through surface engineering, through deposition of suitable coatings. This paper studied the influence of three surface preparation methods involving phosphor bronze substrates concerning the corrosion resistance of commercial coatings having Al-Cu +11% Fe chemical composition. The surface was prepared using three methods: sand blasting, shot blasting and metal polishing with an abrasive disk (with and without a base layer. The deposited coatings were micro-structurally characterised by x-ray diffraction (XRD, optical microscopy and scanning electron microscopy (SEM. Corrosion resistance was evaluated by electrochemical test electrochemical impedance spectroscopy (EIS. Surfaces prepared by sandblasting showed the best resistance to corrosion, so these systems could be a viable alternative for salvaging certain parts in the marine industry. The corrosion mechanisms for the coatings produced are discussed in this research.

  12. Comparative Analysis of Welded and Adhesive Joints Strength Made of Acid-Resistant Stainless Steel Sheets

    Directory of Open Access Journals (Sweden)

    Izabela Miturska

    2017-12-01

    Full Text Available The article presents the selected results of strength tests on the effectiveness of bonding high-alloy steel 1.4310. Sheet steel is one of the materials that are difficult to activate energy. Effective joining of it is difficult, requires selection of the appropriate bonding technology. The paper focuses on the comparative tests the shear strength of one-single lap welded and bonded joints. The welding process was performed 3 groups of samples TIG welding and argon, where the variable value of the welding process was current: 60A, 70A, 80A. The adhesion process was performed in 6 groups of samples which differed in the method of surface preparation and the type of the adhesive. Adhesive joints were made by using adhesive of epoxy resin and a hardener: Epidian 61/TFF at a mass ratio of 100:22 and Epidian 61/IDA at a mass ratio of 100:40. As a way of surface preparation applied 3 different, but simplified and environmentally friendly methods of surface preparation: degreasing with using cleaner Loctite 7061, abrasive machining with P320 and degreasing and grinding with abrasive T800 and degreasing were used. Make joints and curing the adhesive joints were carried out at ambient temperature. Analyzed the joints were tested destructive - which set out the shear strength, in accordance with DIN EN 1465 on the testing machine Zwick / Roell Z150. Based on the results of research it was found that better results were obtained for the maximum welded joints, but this result was similar to the maximum value of the strength of the adhesive bond.

  13. Improvement in nano-hardness and corrosion resistance of low carbon steel by plasma nitriding with negative DC bias voltage

    Science.gov (United States)

    Alim, Mohamed Mounes; Saoula, Nadia; Tadjine, Rabah; Hadj-Larbi, Fayçal; Keffous, Aissa; Kechouane, Mohamed

    2016-10-01

    In this work, we study the effect of plasma nitriding on nano-hardness and corrosion resistance of low carbon steel samples. The plasma was generated through a radio-frequency inductively coupled plasma source. The substrate temperature increased (by the self-induced heating mechanism) with the treatment time for increasing negative bias voltages. X-rays diffraction analysis revealed the formation of nitride phases (ɛ-Fe2-3N and γ'-Fe4N) in the compound layer of the treated samples. A phase transition occurred from 3.5 kV to 4.0 kV and was accompanied by an increase in the volume fraction of the γ'-Fe4N phase and a decrease in that of the ɛ-Fe2-3N phase. Auger electron spectroscopy revealed a deep diffusion of the implanted nitrogen beyond 320 nm. The nano-hardness increased by ~400% for the nitrogen-implanted samples compared to the untreated state, the nitride phases are believed to participate to the hardening. Potentiodynamic polarization measurements revealed that the plasma nitriding has improved the corrosion resistance behavior of the material. When compared to the untreated state, the sample processed at 4.0 kV exhibits a shift of +500 mV and a reduction to 3% in its corrosion current. These results were obtained for relatively low bias voltages and short treatment time (2 h).

  14. Improving the oxidation resistance of 316L stainless steel in simulated pressurized water reactor primary water by electropolishing treatment

    Energy Technology Data Exchange (ETDEWEB)

    Han, Guangdong [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai, 200072 (China); Lu, Zhanpeng, E-mail: zplu@shu.edu.cn [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai, 200072 (China); State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai, 200072 (China); Ru, Xiangkun; Chen, Junjie; Xiao, Qian; Tian, Yongwu [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai, 200072 (China)

    2015-12-15

    The oxidation behavior of 316L stainless steel specimens after emery paper grounding, mechanical polishing, and electropolishing were investigated in simulated pressurized water reactor primary water at 310 °C for 120 and 500 h. Electropolishing afforded improved oxidation resistance especially during the early immersion stages. Duplex oxide films comprising a coarse Fe-rich outer layer and a fine Cr-rich inner layer formed on all specimens after 500 h of immersion. Only a compact layer was observed on the electropolished specimen after 120 h of immersion. The enrichment of chromium in the electropolished layer contributed to the passivity and protectiveness of the specimen. - Highlights: • Duplex oxide films on ground and mechanically polished specimens. • Compact oxide on electropolished specimen after 120 h immersion. • Large spinel outer layer rich in Fe and fine spinel inner layer rich in Cr. • Electropolishing improved oxidation resistance especially at the early stages. • Inhomogeneous Cr-rich inner layer with granular areas affected by surface treatment.

  15. Corrosion Resistance of Nanosized Silicon Carbide-Rich Composite Coatings Produced by Noble Gas Ion Mixing.

    Science.gov (United States)

    Racz, A S; Kerner, Z; Nemeth, A; Panjan, P; Peter, L; Sulyok, A; Vertesy, G; Zolnai, Z; Menyhard, M

    2017-12-27

    Ion beam mixing has been used to produce a silicon carbide (SiC)-rich nanolayer for protective coating. Different C/Si/C/Si/C/Si(substrate) multilayer structures (with individual layer thicknesses falling in the range of 10-20 nm) have been irradiated by Ar+ and Xe+ ions at room temperature in the energy and fluence ranges of 40-120 keV and 1-6 × 1016 ion/cm2, respectively. The effects of ion irradiation, including the in-depth distribution of the SiC produced, was determined by Auger electron spectroscopy depth profiling. The thickness of the SiC-rich region was only some nanometers, and it could be tailored by changing the layer structure and the ion irradiation conditions. The corrosion resistance of the layers was investigated by potentiodynamic electrochemical test in 4 M KOH solution. The measured corrosion resistance of the SiC-rich layers was orders of magnitude better than that of pure silicon, and a correlation was found between the corrosion current density and the effective areal density of the SiC.

  16. 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.

  17. Aerosol characterization and pulmonary responses in rats after short-term inhalation of fumes generated during resistance spot welding of galvanized steel

    Directory of Open Access Journals (Sweden)

    James M. Antonini

    Full Text Available Resistance spot welding is a common process to join metals in the automotive industry. Adhesives are often used as sealers to seams of metals that are joined. Anti-spatter compounds sometimes are sprayed onto metals to be welded to improve the weldability. Spot welding produces complex aerosols composed of metal and volatile compounds (VOCs which can cause lung disease in workers. Male Sprague-Dawley rats (n = 12/treatment group were exposed by inhalation to 25 mg/m3 of aerosol for 4 h/day × 8 days during spot welding of galvanized zinc (Zn-coated steel in the presence or absence of a glue or anti-spatter spray. Controls were exposed to filtered air. Particle size distribution and chemical composition of the generated aerosol were determined. At 1 and 7 days after exposure, bronchoalveolar lavage (BAL was performed to assess lung toxicity. The generated particles mostly were in the submicron size range with a significant number of nanometer-sized particles formed. The primary metals present in the fumes were Fe (72.5% and Zn (26.3%. The addition of the anti-spatter spray and glue did affect particle size distribution when spot welding galvanized steel, whereas they had no effect on metal composition. Multiple VOCs (e.g., methyl methacrylate, acetaldehyde, ethanol, acetone, benzene, xylene were identified when spot welding using either the glue or the anti-spatter spray that were not present when welding alone. Markers of lung injury (BAL lactate dehydrogenase and inflammation (total BAL cells/neutrophils and cytokines/chemokines were significantly elevated compared to controls 1 day after exposure to the spot welding fumes. The elevated pulmonary response was transient as lung toxicity mostly returned to control values by 7 days. The VOCs or the concentrations that they were generated during the animal exposures had no measurable effect on the pulmonary responses. Inhalation of galvanized spot welding fumes caused acute lung toxicity

  18. Weldability Characteristics of Sintered Hot-Forged AISI 4135 Steel Produced through P/M Route by Using Pulsed Current Gas Tungsten Arc Welding

    Science.gov (United States)

    Joseph, Joby; Muthukumaran, S.; Pandey, K. S.

    2016-01-01

    Present investigation is an attempt to study the weldability characteristics of sintered hot-forged plates of AISI 4135 steel produced through powder metallurgy (P/M) route using matching filler materials of ER80S B2. Compacts of homogeneously blended elemental powders corresponding to the above steel were prepared on a universal testing machine (UTM) by taking pre-weighed powder blend with a suitable die, punch and bottom insert assembly. Indigenously developed ceramic coating was applied on the entire surface of the compacts in order to protect them from oxidation during sintering. Sintered preforms were hot forged to flat, approximately rectangular plates, welded by pulsed current gas tungsten arc welding (PCGTAW) processes with aforementioned filler materials. Microstructural, tensile and hardness evaluations revealed that PCGTAW process with low heat input could produce weldments of good quality with almost nil defects. It was established that PCGTAW joints possess improved tensile properties compared to the base metal and it was mainly attributed to lower heat input, resulting in finer fusion zone grains and higher fusion zone hardness. Thus, the present investigation opens a new and demanding field in research.

  19. Emergence of multidrug-resistant Acinetobacter baumannii producing OXA-23 Carbapenemase in Qatar

    Directory of Open Access Journals (Sweden)

    J.-M. Rolain

    2016-05-01

    Full Text Available The objective of our study was to describe the molecular support of carbapenem resistance from randomly selected clinical isolates of multidrug-resistant (MDR Acinetobacter baumannii as a pilot study from the Hamad Medical Corporation (HMC, Qatar. Results of our report will be used to study carbapenemases using molecular techniques in all isolated MDR A. baumannii. Forty-eight MDR A. baumannii were randomly selected from isolates preserved at HMC. Identification of all isolates was confirmed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Antibiotic resistance was tested phenotypically by Phoenix and confirmed by Etest. The molecular support of carbapenemases (blaOXA-23, blaOXA-24, blaOXA-58, blaNDM was investigated by real-time PCR. The epidemiologic relatedness of the isolates was verified by phylogenetic analysis based on partial sequences of CsuE and blaOXA-51 genes. All 48 isolates were identified as A. baumannii and were confirmed to be resistant to most antibiotics, especially meropenem, imipenems, ciprofloxacin, levofloxacin, amikacin, gentamicin and most of the β-lactams; they were sensitive to colistin. All the isolates were positive for blaOXA-23 and negative for the other tested carbapenemase genes. Clonality analysis demonstrated that different lineages were actually circulating in Qatar; and we suggest that an outbreak occurred in the medical intensive care unit of HMC between 2011 and 2012. Here we report the emergence of MDR A. baumannii producing the carbapenemase OXA-23 in Qatar.

  20. Properties of 13HMF steel for steam pipelines as a result of impact and cracking resistance investigations; Wlasnosci stali 13HMF na rurociagi pary swiezej w swietle badan udarnosci i odpornosci na pekanie

    Energy Technology Data Exchange (ETDEWEB)

    Bilous, W.; Wasiak, J.; Hajewska, E.; Szteke, W.; Wagner, T. [Institute of Atomic Energy, Otwock-Swierk (Poland)

    1996-12-31

    Long lasting and safe exploitation of steam pipelines in energetics depends strongly on mechanical properties of material used for tubing production. Most of pipelines installed in polish energetics is made of Cr-Mo-V type steel. The investigation results of such steel (13MHF) concerning the influence of exploitation time on impact and cracking resistance have been presented, discussed and compared with the imported steel P91. 3 refs, 7 figs, 3 tabs.

  1. Rare earth metals influence on mechanical properties and crack resistance of GP240GH and G17CrMo5-5 cast steels

    Directory of Open Access Journals (Sweden)

    M. Gajewski

    2009-10-01

    Full Text Available This paper presents results of research on modification influence of REM on mechanical properties and crack resistance of GP240GH cast carbon steel and G17CrMo5-5 high-temperature cast steel. The tests have been performed on successive industrial melts. The rare earth metals were put into the ladle during tapping of heat melt from the furnace. Each time ca 2000 kg of liquid metals were modified. Because of this the amount of sulphur in the cast steel was decreased and the non-metallic inclusion morphology was significantly changed. There were tested mechanical properties (Re,Rm, plastic properties (A5,Z and impact strength (KV, and on the basis of the three-point bend test the KJC stress intensity factor was evaluated. It was noticed that the REM modification brings essential increase of impact strength as well as fracture toughness determined by KJC factor.

  2. Evaluation of hydrogen-Induced cracking resistance of the In625 laser coating system on a C-Mn steel substrate

    Directory of Open Access Journals (Sweden)

    Vicente Braz Trindade

    Full Text Available Abstract The corrosion of C-Mn steels in the presence of hydrogen sulfide (H2S represents a significant challenge to oil production and natural gas treatment facilities. The failure mechanism induced by hydrogen-induced cracking (HIC in a Inconel 625 coating / C-Mn steel has not been extensively investigated in the past. In the present work, an API 5CT steel was coated with In625 alloy using laser cladding and the HIC resistance of different regions, such as the coating surface, the substrate and HAZ, were evaluated. SEM observations illustrated that all HIC cracks were formed at the hard HAZ after 96h of exposure. No HIC cracks were observed in the substrate and the In625 coating after the same exposure duration. Pitting was recorded in the substrate caused by non-metallic inclusion dissolving.

  3. Bioactive Compound Rich Indian Spices Suppresses the Growth of β-lactamase Produced Multidrug Resistant Bacteria

    Directory of Open Access Journals (Sweden)

    Eadlapalli Siddhartha

    2017-01-01

    Full Text Available Background: Multidrug Resistance (MDR among bacteria become a global concern due to failure of antibiotics, is drawn attention for best antimicrobials from the spices which have been using ancient days in Indian culinary and traditional medicine. Aim and Objectives: The present study was undertaken to evaluate the bioactive compounds and their antibacterial activity in routinely used culinary Indian spices against β-lactamase produced MDR bacteria. Material and Methods: Ethanolic extracts prepared from twenty spices and were evaluated for total phenolics, flavonoids, alkaloids, terpenoids, antioxidant properties, and also assayed their antibacterial activities against β-lactamase producing MDR bacteria (Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. β-Lactamase and cell viability assays were performed in MDR bacteria. Results: Among twenty spices, cinnamon and clove exhibited highest levels of phenolics and terpenoids with elevated antioxidant potential and also showing greater reducing potential at lower concentrations of extract (2.3 and 4.06 µg GAE/gm, respectively. Further, the spices extracts were assessed for antimicrobial activity against β-lactamase produced tested MDR bacteria and observed higher antimicrobial activity with cinnamon, garlic, tamarind and clove at lowest concentrations of MIC and MBC at 16 - 32 µg GAE/ml, as compared to standard drug, amoxiclav (16/8 µg/ml. Spices significantly inhibited the β-lactamase activity (80–94% and also cell viability in tested MDR bacteria. Conclusion: Indian spices consist of rich bioactive profile and antioxidant activity inhibited the bacterial growth effectively by suppressing β-lactamase production in MDR bacteria. Results indicating the spices as functional foods and could be used in prevention of antibiotic resistance.

  4. Control of Resistant Pink Bollworm (Pectinophora gossypiella) by Transgenic Cotton That Produces Bacillus thuringiensis Toxin Cry2Ab

    OpenAIRE

    Tabashnik, Bruce E.; Dennehy, Timothy J.; Sims, Maria A.; Larkin, Karen; Head, Graham P.; Moar, William J.; Carrière, Yves

    2002-01-01

    Crops genetically engineered to produce Bacillus thuringiensis toxins for insect control can reduce use of conventional insecticides, but insect resistance could limit the success of this technology. The first generation of transgenic cotton with B. thuringiensis produces a single toxin, Cry1Ac, that is highly effective against susceptible larvae of pink bollworm (Pectinophora gossypiella), a major cotton pest. To counter potential problems with resistance, second-generation transgenic cotton...

  5. STRUCTURE FORMATION OF WEAR RESISTANT COMBINED TITANIUM-BASED COATINGS ON HIGH SPEED STEEL

    Directory of Open Access Journals (Sweden)

    M. A. Andreyev

    2006-01-01

    Full Text Available The paper proposes a technology of wear resistant coating formation on the basis of Ti. The combined technology includes electro arc evaporation in vacuum and ionic nitriding. Every technological stage of coating application has an influence on tiie structure formation of the combined coating.

  6. DEVELOPMENT OF THE DOPING MATRIX FOR CREATION OF THE BELORUSSIAN INSTRUMENTAL STEELS ON THE BASIS OF STEEL 70K(Y7A PRODUCED BY RUP “BMZ” (view and investigation

    Directory of Open Access Journals (Sweden)

    D. M. Kukuj

    2004-01-01

    Full Text Available Theoretical and practical aspects of production of the Belorussian instrumental steels on the base of the steel of type 70K are considered. The ways of working out of the alloy complex for receiving of the die steels in the conditions of RUP “BMZ” are shown.

  7. High Nb, Ta, and Al creep- and oxidation-resistant austenitic stainless steel

    Science.gov (United States)

    Brady, Michael P [Oak Ridge, TN; Santella, Michael L [Knoxville, TN; Yamamoto, Yukinori [Oak Ridge, TN; Liu, Chain-tsuan [Oak Ridge, TN

    2010-07-13

    An austenitic stainless steel HTUPS alloy includes, in weight percent: 15 to 30 Ni; 10 to 15 Cr; 2 to 5 Al; 0.6 to 5 total of at least one of Nb and Ta; no more than 0.3 of combined Ti+V; up to 3 Mo; up to 3 Co; up to 1 W; up to 0.5 Cu; up to 4 Mn; up to 1 Si; 0.05 to 0.15 C; up to 0.15 B; up to 0.05 P; up to 1 total of at least one of Y, La, Ce, Hf, and Zr; less than 0.05 N; and base Fe, wherein the weight percent Fe is greater than the weight percent Ni wherein said alloy forms an external continuous scale comprising alumina, nanometer scale sized particles distributed throughout the microstructure, said particles comprising at least one composition selected from the group consisting of NbC and TaC, and a stable essentially single phase fcc austenitic matrix microstructure, said austenitic matrix being essentially delta-ferrite-free and essentially BCC-phase-free.

  8. Weathering resistance of thin plasma polymer films on pre-coated steel =

    Science.gov (United States)

    Serra, Ricardo Gil Henriques

    O trabalho apresentado teve origem no projecto de investigacao “Tailored Thin Plasma Polymers Films for Surface Engineering of Coil Coated Steel”, financiado pelo Programa Europeu ECSC Steel Research. Sistemas de aco galvanizado pre-pintado em banda a base de poliester e poliuretano foram submetidos a um processo de polimerizacao por plasma onde um filme fino foi depositado de modo a modificar as propriedades de superficie. Foram usados reactores de catodo oco, microondas e radio frequencia para a deposicao do polimero fino. Os sistemas preparados foram analisados de modo a verificar a influencia do processo de polimerizacao por plasma na alteracao das propriedades barreira dos sistemas pre-pintados em banda. Foi estudado o efeito dos diferentes passos do processo de polimerizacao por plasma, bem como o efeito de diferentes variaveis operatorias. A mistura precursora foi variada de modo a modificar as propriedades da superficie de modo a poder vir a obter maior hidrofobicidade, maior resistencia a marcas digitais, bem como maior facilidade de limpeza. Os testes foram conduzidos em solucao de NaCl 0,5 M. Para o trabalho foram usadas tecnicas de analise da morfologia da superficie como Microscopia de Forca Atomica e Microscopia Electronica de Varrimento. As propriedades electroquimicas dos sistemas foram estudadas por Espectroscopia de Impedancia Electroquimica. A estrutura dos filmes gerados no processo de polimerizacao por plasma foi caracterizada por Microscopia de Transmissao Electronica. A modificacao das propriedades opticas devido ao processo de polimerizacao por plasma foi tambem obtida.

  9. Comprehensive analysis of fractures, microstructure, and physical and mechanical properties for the evaluation of the crack resistance of medium-carbon Cr-Ni-Mo steel

    Science.gov (United States)

    Vorob'ev, R. A.; Dubinskii, V. N.; Evstifeeva, V. V.

    2017-10-01

    The crack resistance of the 38CrNi3MoV (34NiCrMoV14—5. 35NiCrMoV12—5) tempered steel (at various tempering temperatures) has been estimated based on a comprehensive study of the steel fractures, microstructure, physical, and mechanical properties. Stress-intensity factor K 1C at the apex of the crack is growing continuously with an increase in the tempering temperature from 200 to 620°C. This indicates that K 1C is a structural-sensitive parameter, which depends on the steel microstructure and submicrostructure, the fracture mechanism that occurs under these structural conditions, the internal stress level, and the existence of microdefects and microcracks. The linear correlation dependence is found between the coefficient K 1C and the transverse velocity V transv. The obtained results reveal that the acoustic method can be used to quickly and efficiently estimate the crack resistance of the thermostrengthened steel without the recourse to labor-consuming mechanical tests and computations of the K 1C value.

  10. Effect of nano-particulate sol-gel coatings on the oxidation resistance of high-strength steel alloys during the press-hardening process

    Energy Technology Data Exchange (ETDEWEB)

    Yekehtaz, M.; Benfer, S.; Fuerbeth, W. [DECHEMA-Forschungsinstitut, Theodor-Heuss-Allee 25, D-60486 Frankfurt am Main (Germany); Klesen, C.; Bleck, W. [Institut fuer Eisenhuettenkunde der RWTH Aachen, Intzestrasse 1, D-52072 Aachen (Germany)

    2012-10-15

    The need for lighter constructional materials in automotive industries has increased the use of high-strength steel alloys. To enhance passenger's safety press hardening may be applied to steel parts. However, as the steel parts are heated up to 950 C during this process they have to be protected by some kind of coating against the intense oxide formation usually taking place. As the coating systems used so far all have certain disadvantages in this work the ability of nano-particulate thin coatings obtained by the sol-gel process to improve the oxidation resistance of 22MnB5 steel is investigated. The coatings obtained from three sols containing lithium aluminum silicate and potassium aluminum silicate showed the best performance against oxidation. The structural properties of the coating materials were characterized using different methods like XRD and differential thermal analysis. Comparison of the oxidation rate constants proved the ability of the coatings to protect against oxidation at temperatures up to 800 C. Press-hardening experiments in combination with investigations on the thermal shock resistance of the coated samples also showed the ability of the coatings to stay intact during press hardening with only slight spalling of the coatings in the bending areas. The absence of any secondary intermetallic phases and layer residues during laser beam welding experiments on coated samples proves the suitability of the nano-particulate coatings for further industrial processing. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Enhanced inactivation of Salmonella and Pseudomonas biofilms on stainless steel by use of T-128, a fresh-produce washing aid, in chlorinated wash solutions.

    Science.gov (United States)

    Shen, Cangliang; Luo, Yaguang; Nou, Xiangwu; Bauchan, Gary; Zhou, Bin; Wang, Qin; Millner, Patricia

    2012-10-01

    The effect of the washing aid T-128 (generally recognized as safe [GRAS] formulation, composed mainly of phosphoric acid and propylene glycol) on inactivation of Salmonella and Pseudomonas populations in biofilms on stainless steel was evaluated under conditions of increasing organic matter loads in chlorinated wash solutions dominated by hypochlorous acid. Biofilms were formed statically on stainless steel coupons suspended in 2% lettuce extract after inoculation with Salmonella enterica serovar Thompson or Newport or with Pseudomonas fluorescens. Coupons with biofilms were washed in chlorine solutions (0, 0.5, 1, 2, 5, 10, or 20 mg/liter at pH 6.5, 5.0 and 2.9), with or without T-128, and with increasing loads of organic matter (0, 0.25, 0.5, 0.75, or 1.0% lettuce extract). Cell populations on coupons were dispersed using intermittent, pulsed ultrasonication and vortexing and enumerated by colony counts on XLT-4 or Pseudomonas agars. Cell responses to fluorescent viability staining of biofilm treatment washing solutions were examined using confocal laser scanning microscopy. Results showed that 0.1% T-128 (without chlorine) reduced P. fluorescens biofilm populations by 2.5 log(10) units but did not reduce Salmonella populations. For both Salmonella and Pseudomonas, the sanitizing effect of free chlorine (1.0 to 5.0 mg/liter) was enhanced (P biofilms compared to treatments without T-128. Image analysis of surfaces stained with SYTO and propidium iodide corroborate the cultural assay results showing that T-128 can aid in reducing pathogen viability in biofilms and thus can aid in sanitizing stainless steel contact surfaces during processing of fresh-cut produce.

  12. Stainless steel reinforcement as a replacement for epoxy coated steel in bridge decks : final report.

    Science.gov (United States)

    2013-08-01

    The corrosion resistance of 2304 stainless steel reinforcement and stainless steel clad reinforcement was compared to conventional and epoxy-coated reinforcement (ECR). 2304 stainless steel was tested in both the as-received condition (dark mottled f...

  13. Occurrence of multidrug resistance shiga-toxin producing Escherichia coli from milk and milk products

    Directory of Open Access Journals (Sweden)

    Javeed Ahmad Sheikh

    2013-10-01

    Full Text Available Aim: The aim of this study was to assess the hygienic quality of milk and milk products in respect of shiga toxin producingEscherichia coli (STEC.Materials and Methods: 205 samples of raw milk and milk products were processed for isolation of E. coli. The isolates werescreened by mPCR for detection of virulence gene. 52 E. coli isolates were tested against 15 commonly used antibiotics in thefield.Results: Of the 205 samples of milk and milk products 52 (25.36% were positive for E. coli. Out of which 4% samples werepositive for STEC from raw milk and 3.64% from milk products. Also, 25 of 52 (48% of E. coli isolates were multidrugresistance whereas 62.5% of STEC from milk and milk products were multidrug resistance.Conclusions: The milk and milk products production is of poor hygienic quality in and around Jammu region which needsimprovement.

  14. Effects of porosity on corrosion resistance of Mg alloy foam produced by powder metallurgy technology

    Energy Technology Data Exchange (ETDEWEB)

    Aghion, E., E-mail: egyon@bgu.ac.il; Perez, Y.

    2014-10-15

    Magnesium alloy foams have the potential to serve as structural material for regular light-weight applications as well as for biodegradable scaffold implants. However, their main disadvantage relates to the high reactivity of magnesium and consequently their natural tendency to corrode in regular service conditions and in physiological environments. The present study aims at evaluating the effect of porosity on the corrosion resistance of MRI 201S magnesium alloy foams in 0.9% NaCl solution and in phosphate buffer saline solution as a simulated physiological electrolyte. The magnesium foams were produced by powder metallurgy technology using space-holding particles to control the porosity content. Machined chips were used as raw material for the production of Mg alloy powder by milling process. The microstructure of the foams was examined using optical and scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analysis. The corrosion behavior was evaluated by immersion test and potentiodynamic polarization analysis. The results obtained clearly demonstrate that the porosity has a significant effect on the corrosion resistance of the tested foams. Foams with 14–19% porosity have a corrosion rate of 4–10 mcd and 7–15 mcd in NaCl and phosphate buffer saline solution, respectively, compared to only 0.10 mcd for the same alloy in as cast conditions. This increased corrosion degradation of the Mg foams by more than one order of magnitude compared to the cast alloy may limit their potential application in regular and physiological environments. - Highlights: • Porosity has a detrimental effect on corrosion resistance of MRI 201S Mg foams. • 14–19% porosity increases the corrosion rate by more than one order of magnitude. • Accelerated corrosion limits the use of foams in regular/physiological environments.

  15. Cast Steels for Creep-resistant Parts Used in Heat Treatment Plants

    Directory of Open Access Journals (Sweden)

    A. Drotlew

    2012-12-01

    Full Text Available Creep-resistant parts of heat treatment furnaces are in most cases made from high-alloyed chromium-nickel and nickel-chromium ironalloys, both cast and wrought. This paper presents the types of casting alloys used for this particular purpose, since the majority of furnace components are made by the casting process. Standards were cited which give symbols of alloy grades used in technical specifications by the domestic industry. It has been indicated that castings made currently are based on a wider spectrum of the creep-resistant alloy grades than the number of alloys covered by the standards. Alloy grades recommended by the technical literature for individual parts of the furnace equipment were given. The recommendations reflect both the type of the technological process used and the technical tasks performed by individual parts of the furnace equipment. Comments were also made on the role of individual alloying elements in shaping the performance properties of castings.

  16. Cast Steels for Creep-Resistant Parts Used in Heat Treatment Plants

    Directory of Open Access Journals (Sweden)

    Drotlew A.

    2012-12-01

    Full Text Available Creep-resistant parts of heat treatment furnaces are in most cases made from high-alloyed chromium-nickel and nickel-chromium iron alloys, both cast and wrought. This paper presents the types of casting alloys used for this particular purpose, since the majority of furnace components are made by the casting process. Standards were cited which give symbols of alloy grades used in technical specifications by the domestic industry. It has been indicated that castings made currently are based on a wider spectrum of the creep-resistant alloy grades than the number of alloys covered by the standards. Alloy grades recommended by the technical literature for individual parts of the furnace equipment were given. The recommendations reflect both the type of the technological process used and the technical tasks performed by individual parts of the furnace equipment. Comments were also made on the role of individual alloying elements in shaping the performance properties of castings.

  17. Sensory profiles of chocolates produced from cocoa cultivars resistant to Moniliophtora Perniciosa

    Directory of Open Access Journals (Sweden)

    Paula Bacelar Leite

    2013-06-01

    Full Text Available The present study evaluated the sensory quality of chocolates obtained from two cocoa cultivars (PH16 and SR162 resistant to Moniliophtora perniciosa mould comparing to a conventional cocoa that is not resistant to the disease. The acceptability of the chocolates was assessed and the promising cultivars with relevant sensory and commercial attributes could be indicated to cocoa producers and chocolate manufacturers. The descriptive terminology and the sensory profile of chocolates were developed by Quantitative Descriptive Analysis (QDA. Ten panelists, selected on the basis of their discriminatory capacity and reproducibility, defined eleven sensory descriptors, their respective reference materials and the descriptive evaluation ballot. The data were analyzed using ANOVA, Principal Component Analysis (PCA and Tukey's test to compare the means. The results revealed significant differences among the sensory profiles of the chocolates. Chocolates from the PH16 cultivar were characterized by a darker brown color, more intense flavor and odor of chocolate, bitterness and a firmer texture, which are important sensory and commercial attributes. Chocolates from the SR162 cultivar were characterized by a greater sweetness and melting quality and chocolates from the conventional treatment presented intermediate sensory characteristics between those of the other two chocolates. All samples indicated high acceptance, but chocolates from the PH16 and conventional cultivars obtained higher purchase intention scores.

  18. Antiviral activity produced by an IPNV-carrier EPC cell culture confers resistance to VHSV infection.

    Science.gov (United States)

    Jurado, María Teresa; García-Valtanen, Pablo; Estepa, Amparo; Perez, Luis

    2013-10-25

    Infectious pancreatic necrosis virus (IPNV), a fish birnavirus, can establish a persistent infection on epithelioma papulosum cyprinid (EPC) cells producing a carrier state where a small fraction of IPNV-infected cells is maintained in the culture after continuous subculture. The EPC(IPNV) cells are resistant to challenge with IPNV as well as to challenge with viral hemorrhagic septicemia virus (VHSV), a rhabdovirus. In this work, the antiviral effect of the IPNV carrier culture conditioned medium (EPC(IPNV)-CM) was tested and analyzed in detail. EPC cells treated with the carrier culture supernatant become protected against VHSV challenge. Size-fractionation by filtration and acid and heat treatment showed that the IPNV persistently infected cells release an acid-resistant soluble factor in the molecular weight fraction bellow 50 kDa. The capacity of the EPC(IPNV)-CM to induce cytokine genes in EPC cells was also determined by real-time RT-PCR. We found that there is a positive correlation between up-regulation of mx gene expression in EPC cells treated with EPC(IPNV)-CM and protection against VHSV challenge. Our findings indicate that the control of IPNV multiplication in the carrier culture as well as the interference with rhabdovirus replication are connected to the production and release of an antiviral (interferon-like) factor to the medium. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Kinetics of chromium evaporation from heat-resisting steel under reduced pressure

    OpenAIRE

    Kolmasiak, C.

    2012-01-01

    This paper describes a kinetic analysis of the process of chromium evaporation from ferrous alloys smelted under reduced pressure. The study discussed comprised determination of the liquid phase mass transfer coeffi cient as well as the value of the constant evaporation rate. By applying these values as well as the values of the overall mass transfer coeffi cient estimated based on the relevant experimental data, the fractions of resistance of the individual process stages were established.

  20. Effect of a nano-sized TiC particle addition on the flow-assisted corrosion resistance of SA 106B carbon steel

    Science.gov (United States)

    Park, Jin-Ju; Park, Eun-Kwang; Lee, Gyoung-Ja; Rhee, Chang-Kyu; Lee, Min-Ku

    2017-09-01

    Carbon steel with dispersed nano-sized TiC ceramic particles was fabricated by the ex-situ introduction of the particles into the melt, with the flow-assisted corrosion (FAC) resistance then investigated in the presence and absence of TiC nanoparticles using a once-through type of FAC loop test. From the potentiodynamic polarization curves, the current density at any given anodic potential was decreased and the open-circuit potential was increased by the addition of TiC nanoparticles. In addition, when the nano-sized TiC particles were added, the FAC rate was 1.38 times lower than that of carbon steel without TiC nanoparticles, indicating an improvement of the FAC resistance due to the homogeneous distribution of the TiC reinforcing nanoparticles.