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Sample records for heat-resistant alloy hastelloy

  1. Creep properties with short period excessive loadings on a nickel-base heat-resistant alloy Hastelloy XR

    A series of constant load and temperature creep tests and constant temperature creep tests with short period excessive loadings was carried out on a nickel-base heat-resistant alloy Hastelloy XR, which was developed for applications in the High-Temperature Engineering Test Reactor (HTTR), at temperatures ranging from 900 to 1000degC in order to examine the creep behaviors of the alloy under such conditions. The excessive loading levels were the design stress intensity values Sm for Hastelloy XR indicated in the HTTR high-temperature structural design code. Five to six time excessive loadings did not cause significant changes of the minimum creep rate or the time to onset of tertiary creep. About ten time excessive loadings did not cause significant changes of the time to rupture or the rupture elongation. The above-mentioned results suggest that the design stress intensity values Sm for Hastelloy XR have been determined reasonably. (author)

  2. Filler metal development for hastelloy alloy XR

    A method of alloy designing has been proposed and validated to develop the filler metal for Hastelloy alloy XR(nuclear reactor grade of Hastelloy alloy X), which is the candidate material for high temperature structure of High-Temperature Engineering Test Reactor (HTTR). In the filler metal development for Hastelloy alloy XR, materials of two heats were melted and fabricated with special emphasis placed on manufacturing process. One is the trial products (alloy termed 'C') designed by using multiple regression analysis in the range of the chemical composition specified as Hastelloy alloy X. The other is filler metal (alloy termed 'D') with optimum boron content in the same chemical composition as Hastelloy alloy XR. The results of the tests on several key items may be summarized as follows: (1) Weldments with alloy'C' showed higher strength and ductility at elevated temperatures than those of alloy'D'. (2) Weldments with alloy'D' had more excellent strength characteristics at elevated temperatures than those of the other conventional filler metals. (3) As for weldability, the crater cracks were slightly observed in the FISCO cracking test, but those were out of the problem in the degree of cracking from the viewpoint of practical application. The results of qualification tests on weldability showed good performance for all welding conditions of the present experiments. On the other hand, the mechanism of hot cracking initiation and the controlling factors in hot cracking susceptibility with relation to boron content have been clarified for Hastelloy alloy XR base metal. (author)

  3. Filler metal development for Hastelloy alloy XR

    In order to develop the filler metal for Hastelloy alloy XR structure with thick wall, the weldability and high temperature strength properties of Hastelloy alloy XR weldment were investigated using the filler metals, which were alloy-designed on the basis of multiple regression analysis. The former was examined through the chemical analysis in the deposited metal, bend test, FISCO cracking test, optical microscopy and hardness measurement. The latter was investigated by means of tensile and creep test. It was found from these results that the crack susceptibility in the weldment was apparent to be lowered without degrading the high temperature strength properties. Therefore, it is concluded that these filler metals possess excellent performance as the filler metal for Hastelloy alloy XR structure with thick wall. (author)

  4. Electron beam welding of dissimilar heat resistant alloys

    To the welding of the different heat resistant materials for high temperature gas-cooled reactors, electron beam welding was applied, and the high temperature strength of the weld metal was examined as it is necessary for evaluating the welded joints. As the results, the high temperature strength of the weld metal of Hastelloy X and 2.25 Cr-1Mo steel at 500 degC and that of Hastelloy X and SUS316 at 600 degC showed the nearly intermediate values of both parent materials in both cases. Accordingly, when the high temperature strength of electron beam welded metals is evaluated, it is considered that by evaluating at least with the value of a lower strength parent metal, sufficient safety is ensured. In this study, the electron beam welded joints of typical different heat resistant alloys were made, and the tesile strength, creep rupture strength and low cycle fatique strength of the weld metals at high temperature were determined to compare with those of parent alloys. The tested alloys, welding method and high temperature tests are reported. (Koko, I.)

  5. Corrosion properties of heat resistant alloys sheets in helium environment

    Corrosion behavior of heat resistant alloys sheets, which would be used for gas seal elements of an experimental VHTR in Japan, was investigated in a helium environment. Materials were Hastelloy X, Incoloy 800 and Incoloy MA 956. The test temperature range was 700--1,0000C, and the duration time was 1,000 h. Weight change of specimens of Hastelloy X and Incoloy 800 was approximately proportional to (time)sup(1/2), whereas that of Incoloy MA 956 was proportional to (time)sup(1/3). For protection of the alloys, two surface treatments, namely Al2O3 coating with CVD method, and preoxidation in air, were tried. At the Al2O3 coated specimens, oxidation and carburization were almost completely suppressed at a temperature range below 9000C, whereas some features of deterioration of protective film were observed at 1,0000C. Preoxidation in air reduced carburization to some extent, but little advantageous effect on oxidation was observed. Especially, oxide film of Incoloy 800 formed in air was not protective in helium environment. (author)

  6. Thermomechanical treatment of heat-resisting alloys

    Different types of thermomechanical treatment (TMT) are considered in the review. Three schemes which are used for heat resistant ageing alloys are singled out and described in detail: high-temperature thermomechanical treatment (HTMT), mechanico-thermal treatment (MTT) and low-temperature thermomechanical treatment (LTMT). Special attention is paid to perspective LTMT including warm deformation. It is shown that the application of the TMT to concrete alloys permits to increase the strength characteristics in a certain temperature range of the product exploitation without considerable plasticity loss. TMT with the use.of warm deformation in two-phase region looks like the most perspective treatment increasing strength properties, resistance against fatigue destruction and decreasing the sensitivity to the cut

  7. Electric hydraulic treatment of welded joints of heat resistant alloys

    Electric hydraulic treatment is proposed to increase quality and service properties of welded joints of heat resistant alloys and steels. Results of experiments using samples of EhI698 nickel alloy and 12Kh18N10T steel show that electric hydraulic effect relaxes residual stresses preventing from crack formation after welding. Presented are process scheme and treatment conditions

  8. Heat resistant magnesium alloys for automotive powertrain applications

    Anyanwu, I.A.; Gokan, Y.; Nozawa, S.; Kamado, S.; Kojima, Y. [Dept. of Mechanical Engineering, Nagaoka Univ. of Technology, Nagaoka, Niigata (Japan); Takeda, S.; Ishida, T. [Ahresty Corp., Magnesium Products Mfg. Div., Tochigi (Japan)

    2003-07-01

    The suitability of new Mg-Zn-Al-Ca-RE alloys for automotive power train applications are evaluated. Zinc and aluminum contents of the alloys were systematically varied in order to determine alloys with a combination of good diecasting characteristics and high heat resistance. Addition of large amounts of zinc to the alloys results in the formation of intermetallic compounds that crystallize at lower temperatures relative to the matrix, and consequently, fluidity is improved, but hot tearing occurs during diecasting. However, one of the new alloys, Mg-0.5%Zn-6%Al-1%Ca-3%RE alloy is found to exhibit good diecastability and comparable heat resistance with the conventional aluminum alloy, ADC12 that is currently used for diecasting of automotive powertrain parts. (orig.)

  9. Study of creep and rupture behavior for a Ni-base heat resistant alloy improved for high temperature gas-cooled reactor

    Creep-rupture tests of Hastelloy XR-II, a Ni-base heat resistant alloy modified for HTGR environment, were carried out in air and simulated HTGR helium at 700-1000degC up to 26,733 hours in the longest rupture time and about 207,000 hours in total testing times. The data was evaluated for high-temperature structural design using time-temperature parameter method. The boron content of Hastelloy XR-II (about 0.005 mass%) has been increased within the specification of Hastelloy XR. Experimental data and evaluated results were compared with the previous results for Hastelloy XR with low boron content (0.00028 mass%). Followings are a summary of the major findings. 1) Larger ductility is observed for Hastelloy XR-II than Hastelloy XR at higher temperatures. 2) The 100,000 h strength of Hastelloy XR-II is approximately twice of Hastelloy XR at 800 and 900degC. 3) The microstructural observation of creep-ruptured specimens showed a few macrocracks at 700degC, but round-type cavities at grain boundaries were pronounced with increasing temperatures. 4) With regard to the effect of the product forms, the creep-rupture strength of specimens sampled from tubes is slightly higher at 1000degC than that from plates. 5) The creep curves above 900degC were predominantly nonclassical. 6) The allowable stresses of So, Sm and St were computed using similar procedure employed for the previous data on Hastelloy XR with lower boron content. The significant increase in the So and St for Hastelloy XR-II over Hastelloy XR is recognized due to the improvement of both creep strength and creep-rupture ductility. (J.P.N.)

  10. Physicochemical foundations for designing heat resistant alloys of refractory metals

    To manifest foundations for designing refractory metal alloys binary and ternary phase diagrams of Zr, Mo, Cr, W, Ta, Nb have been analysed. Classification of heat resistant alloys by the ways of hardening is carried out, and different hardening mechanisms (solid solution hardening, dispersion hardening and by interstitials) are described in detail. Problems relating to diffusion and element solubility in refractory metrix are discussed. Requirements for the systems perspective for designing refractory alloys are formulated

  11. Metal Dusting of Heat-Resistant Alloys

    Al-Meshari, Abdulaziz I

    2008-01-01

    Metal dusting leads to disintegration of such alloys as iron and nickel-based into a dust of particulate metal, metal carbide, carbon, and/or oxide. It occurs in strongly carburising environments at 400-900C. Literature survey has shown that alloys behave differently in metal dusting conditions based on their composition and the environment. Metal dusting mechanisms for iron and nickel-based alloys have been proposed but, nevertheless, have not been agreed upon and numerous modifications t...

  12. Compatibility of heat resistant alloys with boron carbide, 5

    This paper includes an experimental result of out-of-pile compatibility and capsule design for irradiation test in Japan Materials Testing Reactor (JMTR). The compatibility between sheath material and neutron absorber materials for control rod devices (CRD) was examined for potential use in a very high temperature reactor (VHTR) which is under development at JAERI. The purpose of the compatibility tests are preliminary evaluation of safety prior to irradiation tests. Preliminary compatibility evaluation was concerned with three items as follows : 1) Lithium effects on the penetrating reaction of Incoloy 800H alloy in contact with a mixture of boronated graphite and lithium hydroxide powders, 2) Short term tensile properties of Incoloy 800H and Hastelloy XR alloy reacted with boronated graphite and fracture mode analysis, 3) Reaction behavior of both alloys under transient power conditions of a VHTR. It was clear that the reaction rate constant of the Incoloy 800H alloy was accelerated by doping lithium hydroxide into the boron carbide and graphite powder. The mechanical properties of Incoloy 800H and Hastelloy XR alloy reacted with boronated graphite were decreased. Ultimate tensile strength and tensile ductilities at temperatures over 850 deg C were reduced, but there was no change in the proof (yield) stress. Both alloys exhibited a brittle intergranular fracture mode during transient power conditions of a VHTR and also exhibited severe penetration. Irradiation capsules for compatibility test were designed to simulate three irradiation conditions of VHTR: 1) steady state for VHTR, 2) Transient power condition, 3) Service limited life of CRD. Capsule irradiation experiments have been carried out satisfactorily and thus confirm the validity of the capsule design procedure. (author)

  13. Cavitation erosion behavior of Hastelloy C-276 nickel-based alloy

    Li, Zhen [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Han, Jiesheng; Lu, Jinjun [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Chen, Jianmin, E-mail: chenjm@lzb.ac.cn [State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2015-01-15

    Highlights: • Cavitation erosion behavior of Hastelloy C-276 was studied by ultrasonic apparatus. • The cavitation-induced precipitates formed in the eroded surface for Hastelloy C-276. • The selective cavitation erosion was found in Hastelloy C-276 alloy. - Abstract: The cavitation erosion behavior of Hastelloy C-276 alloy was investigated using an ultrasonic vibratory apparatus and compared with that of 316L stainless steel. The mean depth of erosion (MDE) and erosion rate (ER) curves vs. test time were attained for Hastelloy C-276 alloy. Morphology and microstructure evolution of the eroded surface were observed by scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) and the predominant erosion mechanism was also discussed. The results show that the MDE is about 1/6 times lower than that of the stainless steel after 9 h of testing. The incubation period of Hastelloy C-276 alloy is about 3 times longer than that of 316L stainless steel. The cavitation-induced nanometer-scaled precipitates were found in the local zones of the eroded surface for Hastelloy C-276. The selective cavitation erosion was found in Hastelloy C-276 alloy. The formation of nanometer-scaled precipitates in the eroded surface may play a significant role in the cavitation erosion resistance of Hastelloy C-276.

  14. Cavitation erosion behavior of Hastelloy C-276 nickel-based alloy

    Highlights: • Cavitation erosion behavior of Hastelloy C-276 was studied by ultrasonic apparatus. • The cavitation-induced precipitates formed in the eroded surface for Hastelloy C-276. • The selective cavitation erosion was found in Hastelloy C-276 alloy. - Abstract: The cavitation erosion behavior of Hastelloy C-276 alloy was investigated using an ultrasonic vibratory apparatus and compared with that of 316L stainless steel. The mean depth of erosion (MDE) and erosion rate (ER) curves vs. test time were attained for Hastelloy C-276 alloy. Morphology and microstructure evolution of the eroded surface were observed by scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM) and the predominant erosion mechanism was also discussed. The results show that the MDE is about 1/6 times lower than that of the stainless steel after 9 h of testing. The incubation period of Hastelloy C-276 alloy is about 3 times longer than that of 316L stainless steel. The cavitation-induced nanometer-scaled precipitates were found in the local zones of the eroded surface for Hastelloy C-276. The selective cavitation erosion was found in Hastelloy C-276 alloy. The formation of nanometer-scaled precipitates in the eroded surface may play a significant role in the cavitation erosion resistance of Hastelloy C-276

  15. Studies on the quality optimization of hastelloy alloy XR

    Interim results are reported on the multi-lateral joint research program on improving quality and its assurance basis of Hastelloy alloy XR with special emphasis placed on the effect of small amount of boron in the alloy. In the first phase work the exploratory examination on the optimum boron content was made. The results of the tests on several key items yield the optimum range of boron content as 40 to 70 ppm. The second phase work was organized to perform qualification tests on an industrial scale heat, which was specified its boron content (40 ppm) based on the previous phase work. The tests included weldability, tensile and creep-rupture properties, post aging toughness and corrosion and carburization resistance on different type of products. Tests are in progress, in which considerable difference in the degree of improvement was noted between plate and tube. (author)

  16. Study of creep and rupture behavior for hastelloy alloy XR

    Creep tests of Hastelloy alloy XR (a modified Hastelloy alloy X developed for VHTR application) were carried out at 800, 900 and 10000C up to 310,000 hours in total testing times. The effects of environment (air and simulated VHTR helium), specimen diameters, product forms of the material (tube, plate and bar) and the neutron irradiation were also investigated. The ASME allowable stresses (Ssub(o), Ssub(m), and Ssub(t) in Code Case N-47) required to establish the design limit on the primary system were calculated using the current data. A procedure was developed to calculate equations which represented lower limits of the prediction intervals and the simultaneous tolerance intervals of strength on the basis of regression analysis. Statistical analysis of the three time-temperature parameter methods showed that the Manson-Succop method was better than that of either Larson-Miller or Orr-Sherby-Dorn in respect of curve fitting to the present creep-rupture data. Application of the Garofalo equation to the strain-time data resulted in a creep constitutive equation (tentative version) which represented the average isochronous stress-strain curves. It was recognized that there was little difference between air and helium in the creep-rupture strength up to about 10,000 hours. In helium environment there appeared slight indication that carburization occured in the early stage of exposure but no further carbon intrusion was observed in the steady state creep range. Comparison of creep behaviors among three product forms of the same heat indicated that the bar had superior creep-strength to the tube. This was attributed to the banded precipitation of carbides in the tube. As a result of significant ductility loss due to the neutron irradiation up to 8.7 x 1020n/cm2(th) at 600C, the rupture times reduced below about 20% that of the unirradiated one. (author)

  17. Creep behavior of Ni-base heat resistant alloys for high temperature gas-cooled reactors in decarburizing helium environment

    Creep and corrosion tests of Ni-base heat resistant alloys (Hastelloy XR and XR-II) for high temperature gas-cooled reactors (HTGR) were conducted at 950 deg C in several kinds of helium environments with different impurity compositions in order to examine the effect of decarburizing environment on creep behavior. Creep and corrosion data were analyzed on the basis of theoretical consideration in corrosion to clarify the corrosion mechanism in impure helium. Both alloys were decarburized in helium environment with low partial pressure of oxygen and carbon activity. The decarburization induced degradation of creep properties such as lower creep rupture strength, higher creep rate and earlier start of accelerating creep. Problems of the decarburization of the Hastelloy XR and XR-II in the primary helium coolant of HTGR could be predicted by using a stability diagram for chromium. Controlling impurities to maintain higher partial pressure of oxygen and carbon activity in primary coolant of HTGR is proposed in order to prevent degradation of creep properties of the materials caused by decarburization. (author)

  18. On High-Temperature Behaviours of Heat Resistant Austenitic Alloys

    Calmunger, Mattias

    2015-01-01

    Advanced heat resistant materials are important to achieve the transition to long term sustainable power generation. The global increase in energy consumption and the global warming from greenhouse gas emissions create the need for more sustainable power generation processes. Biomass-fired power plants with higher efficiency could generate more power but also reduce the emission of greenhouse gases, e.g. CO2. Biomass offers no net contribution of CO2 to the atmosphere. To obtain greater effic...

  19. Determination of Stress-Rupture Parameters for Four Heat-Resisting Alloys

    Lidman, William G.

    1947-01-01

    Stress-rupture data for four heat-resisting alloys are analyzed according to equations of the theory of rate processes. A method for determining the four parameters of structure and composition is demonstrated and the four parameters are determined for each of the alloys: forged S816, cast S816, cast S590, and cast Vitallium. It is concluded that parameters can be determined for an alloy provided sufficient reliable experimental data are available.

  20. Permeation of hydrogen in hastelloy C-276 alloy at high temperature

    Tritium is generated by the interaction of neutrons with the lithium and beryllium in the molten salt reactors (MSRs), which use FLiBe as one of solvents of fluoride fuel. Tritium as by-product in the MSRs is an important safety issue because it could easily diffuse into environment through high temperature heat exchangers. The experimental technique of gas driven permeation has been used to investigate the transport parameter of hydrogen in Hastelloy C-276 which is considered as one of the candidate for structure materials. The measurements were carried out at the temperature range of 400-800 Celsius degrees with hydrogen loading pressures ranging from 5*103 to 4*104 Pa. The H diffusive transport parameters for Hastelloy C-276 follow an Arrhenius law in this temperature range. Regarding diffusivity and Sieverts' constant, Hastelloy C-276 has lower values compared with Ni201 alloy. The possible reason may be the trapping effects, which were formed by the alloying elements of Mo and Cr in the matrix. At the same time, the thin oxidation layer formed by the high Cr content could lead to a slower dissociation process of H2 at the surface. (authors)

  1. Constitutive modeling of the visco-plastic response of Hastelloy-X and aluminum alloy 8009

    The viscoplastic behavior of advanced, high temperature, metallic alloys is characterized using the Bodner Partom unified constitutive model. Material parameters for both Hastelloy-X and Aluminum alloy 8009 are obtained for this model. The Bodner-Partom constitutive model is summarized, and a detailed approach for determining the model parameters from experimental data is reviewed. Experimental methods for obtaining the mechanical test data are described. Bodner-Partom model parameters are determined from data obtained in uniaxial, isothermal, monotonic tension or compression tests and isothermal creep tests. Model predictions from the parameters determined are generated and compared to experimental data

  2. Development of heat resistant Mg-Zn-Al-Ca-RE diecasting alloys

    Gokan, Y.; Suzuki, A.; Nozawa, S.; Anyanwu, I.A.; Kamado, S.; Kojima, Y. [Dept. of Mechanical Engineering, Nagaoka Univ. of Technology (Japan); Takeda, S.; Ishida, T. [Ahresty Corp., Magnesium Products Mfg. Div. (Japan)

    2003-07-01

    Diecast Mg-0.5{proportional_to}1%Zn-4{proportional_to}6%Al-1{proportional_to}2%Ca-1{proportional_to}3%RE alloys are evaluated in order to determine the influence of each alloying element on the casting characteristics and heat resistance of the alloys. The result shows that creep properties improve with a decrease in the amount of Zn and Al contents. However, high Al and Zn additions increase the fluidity of the alloys. Ca addition leads to the formation of an Al-Ca compound along the grain boundaries, and this helps to improve creep properties. However, the presence of large quantities of such compounds along the grain boundaries deteriorates the fluidity of the alloys and leads to hot cracking during diecasting. The creep properties of some of the investigated alloys are far superior to those of conventional heat resistant AE42 magnesium alloy. Furthermore, the diecasting characteristics of the new alloys are comparable to those of the best diecasting magnesium alloy, AZ91D, but their creep resistance is far superior to that of AZ91D alloy. (orig.)

  3. Newly developed heat resistant magnesium alloy by thixomolding

    Tsukeda, T.; Uchida, R. [Research and Development Group, Magnesium Process Equipment and Products Div., Japan Steel Works, Ltd., Hiroshima (Japan); Suzuki, M.; Koike, J.; Maruyama, K. [Dept. of Materials Science, Graduate School of Engineering, Tohoku Univ., Sendai (Japan)

    2003-07-01

    Thixomolding of magnesium alloy is an environmentally friendly and safe casting process. This process is capable of near net shape casting from solid feedstock in a single step by injecting metallic slurry into a die cavity with high pressure at semi-solid or fully melted state. In the present work, we investigated the effects of the chemical composition on the creep resistance at elevated temperatures, the corrosion resistance at room temperature and the fluidity during thixomolding about the Mg-Al-Ca-Mm-Sr alloys. Obtained results are the following. (1) The creep resistance increased with increasing additional Ca or Sr content to AM60B. The effect of Ca was larger than that of Sr. The corrosion resistance decreased with increasing Ca content. (2) No significant differences of the corrosion and creep resistance were observed within the Al content of 4 to 8mass% in Mg-Al-3mass%Ca alloys. (3) More than 0.5mass% Mm addition to ACa63 was effective in the corrosion resistant to a certain extent without outstanding decrease of the creep resistance. Moreover, a practical corrosion rate was achieved by more than 0.01mass% Sr addition to ACaE6305. (4) A slight addition (0.01 mass%) of Sr to ACaE6305 was effective in improving the fluidity at a thin wall (1 mm) cavity with thixomolding. (orig.)

  4. Influence of fields of forcs on structure and properties of heat resistant alloy and rapid steel

    The effect of crystallization under impact of heterogeneous fields of forces on the structure and properties of ZhS30 heat resisting is under study. It is ascertained that plasticity increases 2.0 ... 2.5 times and strength grows simultaneous by 10-20% as compared with the ratel level, under the impact of heterogeneous fields of forces in the process of ZhS30 alloy crystllization. Significant improvement of performance of ZhS30 alloy castings is related to an increase of alloying degree of the steel matrix with oriented matrix, dense metal and complete absence of pores

  5. Modification of heat resistant nickel alloys with disperse particles of refractory compounds

    The paper describes a technology for modifying heat resisting nickel alloys. The basic features of this technology are as follows. Low-dispersed refractory articles of modifiers (carbides, nitrides, carbonitrides) are introduced in the melt in the form of briqnettes. Melt temperature and permissible time of modifier insertion into the melt prior to costing are determined depending or alloy composition and objective to be achieved (grain refinement, improvement of strength or plasticity characteristics). Positive modification results are achieved for ZhS32, ZhS6U, XhS3DK alloys

  6. KTA 625 alloy tube with excellent corrosion resistance and heat resistance

    The problems when seamless tubes are produced by using nickel base 625 alloy (61Ni-22Cr-9Mo-Cb) which is known as a corrosion resistant and heat resistant alloyF were examined, and the confirmation experiment was carried out on its corrosion resistance and heat resistance. Various difficulties have been experienced in the tube making owing to the characteristics due to the chemical composition, but they were able to be solved by the repeated experiments. As for the characteristics of the product, the corrosion resistance was excellent particularly in the environment containing high temperature, high concentration chloride, and also the heat resistance was excellent in the wide temperature range from normal temperature to 1000 deg C. From these facts, the wide fields of application are expected for these alloy tubes, including the evaporation and concentration equipment for radioactive wastes in atomic energy field. Expecting the increase of demand hereafter, Kobe Steel Ltd. examined the problems when seamless tubes are produced from the 625 alloy by Ugine Sejournet process. The aptitude for tube production such as the chemical composition, production process and the product characteristics, the corrosion resistance against chloride, hydrogen sulfide, polythionic and other acids,F the high temperature strength and oxidation resistance are reported. (Kako, I.)

  7. KTA 625 alloy tube with excellent corrosion resistance and heat resistance

    Fujiwara, Kazuo (Kobe Steel Ltd. (Japan). Central Research and Development Lab.); Kadonaga, Toshiki; Kikuma, Seiji

    1982-11-01

    The problems when seamless tubes are produced by using nickel base 625 alloy (61Ni-22Cr-9Mo-Cb) which is known as a corrosion resistant and heat resistant alloy were examined, and the confirmation experiment was carried out on its corrosion resistance and heat resistance. Various difficulties have been experienced in the tube making owing to the characteristics due to the chemical composition, but they were able to be solved by the repeated experiments. As for the characteristics of the product, the corrosion resistance was excellent particularly in the environment containing high temperature, high concentration chloride, and also the heat resistance was excellent in the wide temperature range from normal temperature to 1000 deg C. From these facts, the wide fields of application are expected for these alloy tubes, including the evaporation and concentration equipment for radioactive wastes in atomic energy field. Expecting the increase of demand hereafter, Kobe Steel Ltd. examined the problems when seamless tubes are produced from the 625 alloy by Ugine Sejournet process. The aptitude for tube production such as the chemical composition, production process and the product characteristics, the corrosion resistance against chloride, hydrogen sulfide, polythionic and other acids, the high temperature strength and oxidation resistance are reported.

  8. Spectral analysis of heat resisting alloys smelted in vacuum arc furnaces

    Information is provided on the preparation of a representative cast specimen for spectral analysis selected from among ingots of heat-resistant alloys Ni-Mo-W-Zr, Mo-Ti-Zr-Nb-W, Cr-Y-V-B. The specimen is prepared by fusing in a high-frequency electromagnetic field in a suspended state with subsequent pouring of the liquid metal into a copper collapsable mould

  9. Energy-force parameters of hot swaging for heat resisting alloys

    The process of drop forging is considered, which includes five blows. The change of the force is shown along during the drop forging of the disc made of heat resistant EhP742 alloy using a hydraulic press with the force of 30000 f. It is found out that pressing permits to decrease considerably energy consumptions mainly at the expense of the excluding additional heatings of articles, and to uduce the technological cycle of pressing, to decrease its labour-consumption

  10. Determination of ruthenium in heat-resistant nickel alloys by atomic emission spectrometry with inductively coupled plasma

    A technique for measuring 0.5-6.5 mass% ruthenium in heat-resistant nickel alloys using atomic emission spectrometry with inductively coupled plasma was developed. The measurement precision (repeatability and reproducibility) was determined. (author)

  11. Experiment planning in the investigation of the heat-resistance of the iron-nickel-chromium-silicon-aluminium system alloys

    The general laws governing variation in the heat-resistance within the temperature range of 1100 to 1300 deg C, of alloys of iron-nickel-chromium-silicon-aluminium system have been examined depending on their composition. The heat resistance of the alloys was assessed after 500-hour holding according to an increase in the mass of cylindrical samples. Using the experimental data as the basis, the heat-resistant models were developed according to the composition of alloys. It has been established that the alloy containing 52.7% Ni; 22.4% Cr; 1.8% Si; 2.49% Al (the balance is iron), is best with regard to its heat resistance at a temperature of 1300 deg C

  12. APT characterization of a high strength corrosion-resistant Ni-Cr-Mo HastelloyR C-22HSTM alloy

    Full text: The versatile C-type Ni-Cr-Mo alloys are well known for their corrosion resistance. These alloys have been used for many years in a wide variety of applications such as heat exchangers, scrubbers, reaction vessels, etc. as they exhibit significantly higher strength than most stainless steels. The strength of these alloys may be further increased by cold working. However, this mechanical processing approach limits the size and geometry of the final components. In addition, the high strength is lost in welds and associated heat affective zones. A new high strength corrosion-resistant alloy Ni-21% Cr-17% Mo, HASTELLOY C-22HS, has recently been developed to overcome these problems. This general purpose corrosion-resistant alloy may be used at temperatures of up to at least 600oC. Potential applications for this corrosion resistant high strength alloy include shafting, agitators, fan blades, hubs, springs, fasteners, valves, dies, rings and gaskets. The composition of the HASTELLOY C-22HS alloy used in this study was Ni, 20.6 wt. % Cr, 16.6% Mo, 1.1% Fe, 0.33% Al, 0.29% Mn, 0.11% Nb, 0.004% C and 0.004% B. The microstructure of the HASTELLOY C-22HS alloy was characterized in the age hardened condition - 16 h at 705oC, furnace cooled to 605oC, 32 h at 605oC and air cooled. The microstructure of this age hardened alloy was characterized with the Oak Ridge National Laboratory local electrode atom probe. The corrosion resistance of this alloy in HCl at 52oC and H2SO4 at 79oC was found to be similar to N06022 alloy and better than N07725 alloy. The yield strength of this alloy and N06022 were similar in the mill annealed condition. After the age hardening treatment, the 0.2% yield strength of the HASTELLOY C-22HS alloy increased from 222 to 542 MPa. The tensile elongation and the reduction in area of the age hardened alloy were 40% and 50%, respectively at room temperature and 48% and 66%, respectively at 595oC. Atom probe tomography of the HASTELLOY C-22HS alloy revealed that the microstructure consisted of fine (∼10-30 nm diameter) approximately spherical molybdenum-enriched Ni2(Cr, Mo) precipitates in an aluminum-, iron-, silicon-, and manganese-enriched matrix. The morphology of these precipitates was significantly finer than the lenticular Ni2(Cr, Mo) precipitates previously observed in a HAYNES 242 alloy. Ref. 1 (author)

  13. Studies on the permeation of hydrogen and tritium through heat resistant alloys

    At temperatures of 750 to 9500C the permeation of hydrogen through bare, heat resistant alloys was studied from 1 to 40 bar, the diffusion and permeation of tritium in the partial pressure range of 10-4 bar. Among the alloys studied were Incoloy 800, 800 H, 802, Inconel 617, 625, the Ni-based alloy Nimonic PE 13, and several non-commercial steels. At a given temperature, the permeation rate through samples with clean surfaces - substantially free of oxide films - was found to be proportional to the square root of the hydrogen pressure. The C and the Cr contents of the steels investigated proved to exert a strong influence on the activation energies of diffusion and permeation. In some alloys a reduction of the permeation rate was observed that can be attributed to the precipitation of intermetallic phases. In one case a decrease of the permeation rate occured during the measurements due to a phase transformation. (orig.)

  14. Electric effect on formation of gas-circulation coatings on heat resistant alloy

    The formation kinetics for aluminide coating on heat resisting alloy ZhS6U is under study. Polished specimens to be coated were mounted in a reaction chamber with a NiCrAlY powder saturating mixture placed at the bottom. Electric potential was applied between heated ZhS6U alloy specimens and the bottom of the chamber. It is shown that the application of pulsed electric potentials accelerates the growth of diffusion coatings on the alloy. Electric field effect starts at some definite threshold value of direct voltage and manifests itself near the temperature of gamma-phase dissolution in the alloy. The application of pulsed electric potentials makes it possible to form multicomponent coatings of variable composition

  15. Relation of Engine Turbine-blade Life to Stress-rupture Properties of the Alloys, Stellite 21, Hastelloy B, Cast S-816, Forged S-816, X-40, Nimonic 80, Refractaloy 26, N-155, and Inconel X

    Garrett, F B; Yaker, C

    1951-01-01

    An investigation was conducted to relate the engine performance of the heat-resistant alloys, Stellite 21, Hastelloy B, cast S-816, forged S-816, X-40, Nimonic 80, Refractory 26, N-155, and Iconel X to their stress-rupture properties. The engine test consisted of the repetition of a 20-minute cycle, 15 minutes at rated speed and approximately 5 minutes at idle. The results of the investigation indicated a direct correlation between stress-rupture life and blade life for the relatively low-strength alloys. The stress-rupture life and blade life for the relatively high-strength alloys did not correlate because of the effects of the vibratory stresses and the corrosive-gas atmosphere.

  16. Relationship between carburization and zero-applied-stress creep dilation in Alloy 800H and Hastelloy X

    Typical HTGR candidate alloys can carburize when exposed to simulated service environments. The carbon concentration gradients so formed give rise to internal stresses which could cause dilation. Studies performed with Hastelloy X and Alloy 800H showed that dilations of up to almost 1% can occur at 10000C when carbon pickup is high. Dilation was normally observed only when the carbon increase was >1000 μg/cm2 and ceased when the diffusing carbon reached the center of the specimen

  17. Relationship between carburization and zero-applied-stress creep dilation in Alloy 800H and Hastelloy X

    Typical HTGR candidate alloys can carburize when exposed to simulated service environments. The carbon concentration gradients so formed give rise to internal stresses which could cause dilation. Studies performed with Hastelloy X and Alloy 800H showed that dilations of up to almost 1% can occur at 10000C when carbon pickup is high. Dilation was normally observed only when the carbon increase was >1000 μg/cm2 and ceased when diffusing carbon reached the center of the specimen. (Auth.)

  18. About thermal cracking in joint at the heat-resistant alloys welding

    By welding heat-resistant nickel and cobalt alloys cracks are formed initially by dendrite boundaries in solid-liquid state inform of microcracks 20-100 ?m long, developing under impact of stretching tensions and joining into main crack both by the dendrite boundaries and by secondary boundaries. The mechanism of hot cracks formation was studied in the process of metallographic studies by the IMET-P methodology on working part of compact samples, subjected to deformation by velocities lower as critical ones

  19. Influence of titanium: aluminum ratio in heat-resistant nickel alloys on their resistance to high-temperature salt corrosion

    This paper discusses how the ratio of titanium to aluminum in the range from zero to four with a total content of 2-8% influences the resistance of heat-resistant nickel-based alloys to sulfate and chloride melts. When the Ti/Al ratio lies between zero and one, there is marked weakening of sulfide corrosion, but this parameter has little influence on the resistance to chlorides. In order to obtain good mechanical properties and resistance to high-temperature corrosion, heat-resistant alloys should be alloyed with approximately equal amounts of titanium and aluminum

  20. Development testing of the two-watt RTG heat source and Hastelloy-S/T-111 alloy compatibility studies

    The two-watt radioisotope thermoelectric generator heat source capsules were tested to determine their survivability under extreme environmental conditions: high external pressure, high impact, and high internal pressure. Test results showed that the capsules could withstand external pressures of 1,000 bars and impacts at velocities near 150 meters per second. However, the results of the internal pressure tests (stress-rupture) were not so favorable, possibly because of copper contamination, leading to a recommendation for additional testing. A material compatibility study examined the use of Hastelloy-S as a material to clad the tantalum strength member of the two-watt radioisotopic heat source. Test capsules were subjected to high temperatures for various lengths of time, then cross sectioned and examined with a scanning electron microscope. Results of the study indicate that Hastelloy-S would be compatible with the underlying alloy, not only at the normal operating temperatures of the heat source, but also when exposed to the much higher temperatures of a credible accident scenario

  1. Development of heat resistant Pb-free joints by TLPS process of Ag and Sn-Bi-Ag alloy powders

    Ohnuma I.; Kainuma R.; Ishida K.

    2012-01-01

    TLPS (Transient Liquid Phase Sintering) process is a candidate method of heat-resistant bonding, which makes use of the reaction between low-melting temperature powder of Sn-Bi base alloys and reactive powder of Ag. During heat treatment above the melting temperature of a Sn-Bi base alloy, the molten Sn-Bi reacts rapidly with solid Ag particles, which results in the formation of heat-resistant intermetallic compound (IMC). In this study, the TLPS properties between Sn-17Bi-1Ag (at.%) po...

  2. Corrosion products and formation mechanism of hastelloy C-276 alloy in supercritical water at 600℃

    The corrosion products of nickel-base alloy Hastelloy C-276 was investigated in supercritical water (SCW) at 600℃/25 MPa through grazing incidence X-ray diffractometry, X-ray photoelectron spectroscopy and scanning electron microscopy, respectively. The results show that the uniform and complete oxide film was observed in SCW, which was identified to mainly consist of NiO, NiCr2O4, Cr2O3 and MoO2; The oxide films that had duplex structure were in poor in Ni and Mo, but the inner layer was rich in Cr. The loose outer layer lacked of protective, while the compact inner layer was favor of antioxidation. The formation mechanism of corrosion products on alloy C-276 in supercritical water seemed to be similar to that in high temperature water. The Ni(OH)2, NiO outer layer grew by dissolution and precipitation mechanism, while the Cr2O3 inner layer oxide was formed by oxygen diffusing inward and reacting with the retained Cr. (authors)

  3. Laser texturing of Hastelloy C276 alloy surface for improved hydrophobicity and friction coefficient

    Yilbas, B. S.; Ali, H.

    2016-03-01

    Laser treatment of Hastelloy C276 alloy is carried out under the high pressure nitrogen assisting gas environment. Morphological and metallurgical changes in the laser treated layer are examined using the analytical tools including, scanning electron and atomic force microscopes, X-ray diffraction, energy dispersive spectroscopy, and Fourier transform infrared spectroscopy. Microhardness is measured and the residual stress formed in the laser treated surface is determined from the X-ray data. The hydrophibicity of the laser treated surface is assessed using the sessile drop method. Friction coefficient of the laser treated layer is obtained incorporating the micro-tribometer. It is found that closely spaced laser canning tracks create a self-annealing effect in the laser treated layer and lowers the thermal stress levels through modifying the cooling rates at the surface. A dense structure, consisting of fine size grains, enhances the microhardness of the surface. The residual stress formed at the surface is compressive and it is in the order of -800 MPa. Laser treatment improves the surface hydrophobicity significantly because of the formation of surface texture composing of micro/nano-pillars.

  4. Comparison of creep behavior under varying load/temperature conditions between Hastelloy XR alloys with different boron content levels

    In the design of the high-temperature components, it is often required to predict the creep rupture life under the conditions in which the stress and/or temperature may vary by using the data obtained with the constant load and temperature creep rupture tests. Some conventional creep damage rules have been proposed to meet the above-mentioned requirement. Currently only limited data are available on the behavior of Hastelloy XR, which is a developed alloy as the structural material for high-temperature components of the High-Temperature Engineering Test Reactor (HTTR), under varying stress and/or temperature creep conditions. Hence a series of constant load and temperature creep rupture tests as well as varying load and temperature creep rupture tests was carried out on two kinds of Hastelloy XR alloys whose boron content levels are different, i.e., below 10 and 60 mass ppm. The life fraction rule completely fails in the prediction of the creep rupture life of Hastelloy XR with 60 mass ppm boron under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR with below 10 mass ppm boron. The change of boron content level of the material during the tests is the most probable source of impairing the applicability of the life fraction rule to Hastelloy XR whose boron content level is 60 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the two stage creep test conditions from 1000 to 900degC. The trend observed in the two stage creep tests from 900 to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (J.P.N.)

  5. Characterization of grain boundaries by fractal geometry and creep-rupture properties of heat-resistant alloys

    There is a certain 'self-similarity' between the parts and the whole of a microstructure in metallic materials, although the microstructures are generally complicated and irregular in nature. Serrated grain boundaries which are composed of irregular ledges and steps are effective in improving the high-temperature strength of heat-resistent alloys. There are some differences in the 'degree' (ruggedness) among the grain boundaries in heat-resistant alloys, depending on alloy composition and heat treatments. In this study, serrated grain boundaries are characterized by estimating the fractal dimension, and the relation between the increase of the fractal dimension of grain boundaries and the improvement of creep-rupture properties by serrated grain boundaries is discussed. (orig.)

  6. Crevice Corrosion of hastelloy C-276 and Inconel-625 Alloys in Chloride Environment, Effect of Bulk Solution Environment

    Electrochemical techniques have been applied to study the crevice corrosion resistance of two nickel-based alloys *namely, hastelloy C-276 and Inconel-625 in acidified sodium chloride aerated solution (pH=3), in the temperature range 25-100 degree C. Cyclic polarization (where the potential is reversed at 1.0 V(SCE) was performed on the two alloys at 25,50 and 100 degree C in the same pH chloride solution. Both alloys were resistant to this type of attack at 25 degree C, and both alloys were severely attacked at 100 degree C. This was clearly reflected in the value of ?I in the hysteresis loop and also in the values of both Ecorr. and Eb. The electrochemical results were substantiated by SEM investigation. The findings were interpreted in terms of the effect of chromium and molybdenum contents on the passive film characteristics and the influence of pH during polarization. 7 figs

  7. Glow discharge mass spectrometric analysis of nickel-based heat-resisting alloys

    GD-MS analysis of nickel-based heat-resisting alloys has been performed using a VG 9000 glow discharge (GD) mass spectrometer. Concentrations of not only alloying elements (Al, Si, Ti, V, Cr, Mn, Fe, Co, Cu, Y, Nb, Mo and W) but also trace elements (B, C, Mg, P, S, Zn, Ga, As, Zr, Cd, Sn, Sb, Te, Pb and Bi) were successfully determined in disk shaped samples. The examination of spectral interference confirmed the following. The influence of manganese argide (55Mn40Ar+) on the ion beam intensity of 95Mo+ was negligible because manganese content of the alloys is usually less than 1 mass%. Mass spectra of 31P+ and 32S+ may be affected by the spectral interference of 62Ni2+ and 64Ni2+, respectively, due to the matrix element. However, these ion species were sufficiently separated at the mass resolution 5000 (m/?m, at 5% peak height) used in this study. Relative sensitivity factors (RSFs) were determined by analyzing standard reference materials: JAERI CRMs, a NIST SRM, a BS CRM, BCS CRMs and the alloys prepared in our Institute. The average RSF-values obtained for Ni=1 were 0.436 for Al, 0.826 for Si, 0.281 for Ti, 0.375 for V, 1.480 for Cr, 1.122 for Mn, 0.754 for Fe, 0.653 for Co, 3.321 for Cu, 0.303 for Y, 0.436 for Nb, 0.862 for Mo, 0.935 for Ta and 1.052 for W. The analytical accuracy (?d) obtained was comparable to that of FP-XRF analysis, except for chromium and iron determinations. Relative standard deviations (RSDs) of five replicate measurements were within about 2.5%, except for phosphorus (P; 0.003 mass%, RSD; 3.31%) and sulfur (S; 0.005 mass%, RSD; 3.08%). GD-MS analytical values for ODS MA6000 alloy were obtained using a RSF correction program, and the values were in good agreement with those obtained by FP-XRF and by chemical analysis (author)

  8. Aging of a cast 35Cr–45Ni heat resistant alloy

    Highlights: ► The as-cast microstructure is made of an austenitic matrix and primary carbides. ► The carbides are of two different types: Cr- and Nb-rich. ► The microstructure changes during aging. ► These microstructural changes result in the degradation of mechanical properties. - Abstract: The microstructural evolution during aging and its effect on the mechanical properties of a centrifugally cast 35Cr–45Ni heat resistant alloy was studied by means of optical and electron microscopy, and by mechanical testing in samples aged in air at 750 °C for a period of time of up to 1000 h. The as-cast microstructure consisted of an austenitic matrix and a network of two types of primary carbides that were identified as NbC and M7C3 by their light and dark tones when viewed in backscattered electron mode in a scanning electron microscope. Aging promoted the occurrence of different phenomena such as the transformation of primary M7C3 to M23C6 carbides, precipitation of secondary M23C6 carbides and the transformation of NbC to Nb3Ni2Si. It was found that aging promoted an increase in Vickers microhardness of more than 50%, the increment in tensile strength of around 20% and the reduction in ductility of close to 70%.

  9. Regularities of phase composition and structure formation in intermetallide-strengthened heat-resistant titanium alloy under hydrogen addition

    The phase composition and structure of the Ti-9Al-1Mo-4Sn-3Zr (mas.%) heat resistant alloy under hydrogen addition are studied. It is shown, that hydrogen decreases the temperature of the ?+?(?2) ? ? transition by 220 deg C by its concentration up to 1.0 mas.%. The hydrogen effect on the change of the phase composition is similar top the effect of the traditional ?-stabilizing elements

  10. Using of phase diagrams of ternary systems of transition carbide-containing metals in developing heat resisting hard alloys

    Heat resisting hard alloys containing refractory carbides are studied for a possibility of their production with application of cast alloys whose disperse structure is formed during their cooling crystallization. With this aim it is very important to study phase diagrams, in particular within the crystallization range. Two types of cast hard alloys are considered: cast tungsten carbides (rhelit) and refractory eutectics (W-MIVC+ first of all). It is shown that success in studying the M-C and M-M-C phase diagrams promotes a wider use of molybdenum in hard alloys as a tungsten substitute production of multicomponent of the both types. Factors are discussed that determine the character of phase equilibria in these systems and physicochemical premises of a directed search for a composition of cast refractory wear resistant carbide-containing alloys (ternary and multicomponent)

  11. Aging of a cast 35Cr-45Ni heat resistant alloy

    Sustaita-Torres, Ireri A., E-mail: ireri.sustaita@gmail.com [Unidad Academica de Ingenieria, Universidad Autonoma de Zacatecas, 98000 Zacatecas (Mexico); Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, 66450 San Nicolas de los Garza (Mexico); Haro-Rodriguez, Sergio, E-mail: haros907@hotmail.com [Unidad Academica de Ingenieria, Universidad Autonoma de Zacatecas, 98000 Zacatecas (Mexico); Guerrero-Mata, Martha P., E-mail: martha.guerreromt@uanl.edu.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, 66450 San Nicolas de los Garza (Mexico); Garza, Maribel de la, E-mail: maribeldelagarza@yahoo.com.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon, 66450 San Nicolas de los Garza (Mexico); Valdes, Eduardo, E-mail: eduardo.valdes.57@gmail.com [Instituto Tecnologico de Saltillo, 25280 Saltillo (Mexico); Deschaux-Beaume, Frederic, E-mail: deschaux@iut-nimes.fr [Mechanical and Civil Engineering Laboratories, Universite de Montpellier 2, IUT Nimes, 30907 Nimes (France); and others

    2012-04-16

    Highlights: Black-Right-Pointing-Pointer The as-cast microstructure is made of an austenitic matrix and primary carbides. Black-Right-Pointing-Pointer The carbides are of two different types: Cr- and Nb-rich. Black-Right-Pointing-Pointer The microstructure changes during aging. Black-Right-Pointing-Pointer These microstructural changes result in the degradation of mechanical properties. - Abstract: The microstructural evolution during aging and its effect on the mechanical properties of a centrifugally cast 35Cr-45Ni heat resistant alloy was studied by means of optical and electron microscopy, and by mechanical testing in samples aged in air at 750 Degree-Sign C for a period of time of up to 1000 h. The as-cast microstructure consisted of an austenitic matrix and a network of two types of primary carbides that were identified as NbC and M{sub 7}C{sub 3} by their light and dark tones when viewed in backscattered electron mode in a scanning electron microscope. Aging promoted the occurrence of different phenomena such as the transformation of primary M{sub 7}C{sub 3} to M{sub 23}C{sub 6} carbides, precipitation of secondary M{sub 23}C{sub 6} carbides and the transformation of NbC to Nb{sub 3}Ni{sub 2}Si. It was found that aging promoted an increase in Vickers microhardness of more than 50%, the increment in tensile strength of around 20% and the reduction in ductility of close to 70%.

  12. Etude expérimentale du soudage par laser YAG de l'alliage base nickel Hastelloy X Experimental study of YAG laser welding of nickel base alloy Hastelloy X

    Graneix Jérémie

    2013-11-01

    Full Text Available Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cette étude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique. The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental study has identified the field of weldability of this alloy to meet the specific requirements of the aerospace industry.

  13. Variation of microstructures and mechanical properties of hot heading process of super heat resisting alloy Inconel 718

    Metal forming is the process changing shapes and mechanical properties of the workpiece without initial material reduction through plastic deformation. Above all, because of hot working carried out above recrystallization temperature can be generated large deformation with one blow, it can produce with forging complicated parts or heat resisting super alloy such as Inconel 718 has the worst forgeability. In this paper, we established optimal variation of hot heading process of the Inconel 718 used in heat resisting component and evaluated mechanical properties hot worked product. Die material is SKD61 and initial temperature is 300 .deg. C. Initial billet temperature and punch velocity changed, relatively. Friction coefficient is 0.3 as lubricated condition of hot working. CAE is carried out using DEFORM software before marking the tryout part, and it is manufactured 150 ton screw press with optimal condition. It is know that forming load was decreased according to decreasing punch velocity

  14. Helium dilution effect on hydrogen permeation in 316L stainless steel and nickel-base heat-resistant alloys

    Effects of inert-gas dilution on hydrogen permeation have been investigated in 316L stainless steel, Inconel 600, Inconel 750, Nimonic 80A and Hastelloy X at 1173 K and 1073 K, by employing a gas-flow system. We used gas mixtures of hydrogen and helium, whose hydrogen concentration ranged from 10-5 to 10-1. For the steady-state permeation, the dilution of hydrogen caused no anomalous effects and the permeation rate conformed to Sieverts' law. However, for the transient state, the hydrogen permeation was retarded by the dilution with helium. The retardation effect is discussed in terms of an adsorption model and explained by a decrease in sticking probability at the alloy surface with the dissociative adsorption of hydrogen. (orig.)

  15. Hydrogen diffusion and solution at high temperatures in 316L stainless steel and nickel-base heat-resistant alloys

    Hydrogen-permeation behaviors of 316L stainless steel, Inconel 600, Inconel 750, Nimonic 80A and Hastelloy X at 873 K-1173 K have been investigated under a pressure range of 0.1 MPa-0.7 MPa by using a gas-flow system. Measurements have been carried out by use of a helium-carrier-gas method. It has been proved that this method is good for examining transient-permeation behaviors as well as steady-state permeation if the instrumental time-lag is taken into account. Diffusivity and solubility of hydrogen for the alloys are derived from the transient and steady-state permeation. The γ'-precipitation strengthened alloys - Inconel 750 and Nimonic 80A - show a larger activation energy of diffusion and a smaller solution heat than the other nickel-base alloys. This result is ascribed to the trapping effect due to titanium in the former alloys, i.e. solute titanium atoms and/or γ'-precipitations. (orig.)

  16. Development of heat resistant Pb-free joints by TLPS process of Ag and Sn-Bi-Ag alloy powders

    Ohnuma I.

    2012-01-01

    Full Text Available TLPS (Transient Liquid Phase Sintering process is a candidate method of heat-resistant bonding, which makes use of the reaction between low-melting temperature powder of Sn-Bi base alloys and reactive powder of Ag. During heat treatment above the melting temperature of a Sn-Bi base alloy, the molten Sn-Bi reacts rapidly with solid Ag particles, which results in the formation of heat-resistant intermetallic compound (IMC. In this study, the TLPS properties between Sn-17Bi-1Ag (at.% powder with its liquidus temperature of 200°C and pure Ag powder were investigated. During differential scanning calorimetry (DSC measurement, an exothermic reaction and an endothermic reaction occurred, which correspond to the formation of the e-Ag3Sn IMC phase and the melting of the Sn-17Bi-1Ag alloy, respectively. After the overall measurement, the obtained reactant consists of the Ag3Sn-IMC and Bi-rich phases, both of which start melting above 250°C, with a small amount of the residual Sn-Bi eutectic phase. These results suggest that the TLPS process can be applied for Pb-free heatresistant bonding.

  17. Evaluation on materials performance of Hastelloy Alloy XR for HTTR uses. 3. Manufacture of filler metal and its weldability

    Weldability on Hastelloy Alloy XR base metals and filler metals for the High Temperature Engineering Test Reactor (HTTR) components was examined by means of chemical analysis of deposited metals, optical microscopy, hardness measurements, FISCO and bend test. All of the results obtained by each test showed favorable performance. In particular, in the bend test which is considered to be critical pass, the optimization of B and C contents in the filler metal resulted in low susceptibility to weld cracking. Therefore, it is concluded that the excellent performance of the filler metal used and the effectiveness of narrowing groove are confirmed, and there is no problem from the viewpoint of engineering with respect to HTTR application. (author)

  18. Evaluation on materials performance of hastelloy alloy XR for HTTR uses. 4. Tensile properties of base metals and welded joints

    Tensile properties due to thermal aging on Hastelloy Alloy XR base metals and welded joints were investigated as a series of evaluation test on the base metals and filler metals for the High Temperature Engineering Test Reactor (HTTR) components. Tensile test in air was performed at R.T. and then same temperatures as the thermal aging temperatures after the specimens were aged at 800, 900 and 1000degC for 1000hrs. In comparison with the previous data, the present results had no significant difference on the strength characteristics, and were in the previous data band on the ductility. Therefore, it is concluded that these base metals and filler metals for the HTTR components have excellent tensile properties. (author)

  19. Electrochemical investigation of the effect of different laser surface treatments on Hastelloy G alloy

    Toor, Ihsan H.; Yilbas, Bekir S.; Hussein, Mohammed A.; Zafar, Mohammed N. [King Fahd Univ. of Petroleum and Minerals (KFUPM), Dhahran (Saudi Arabia). Dept. of Mechanical Engineering; Karatas, Cihan [Hacettepe Univ., Ankara (Turkey). Engineering Faculty

    2013-10-15

    In the present study, the corrosion resistance behavior of untreated and laser treated Hastelloy was examined. The electrochemical tests including potentiodynamic polarization, Tafel analysis, and linear polarization resistance were carried out in deaerated 0.5% NaCl aqueous solution at room temperature. Surface roughness was measured to correlate it with corrosion resistance properties of the materials. Surface morphology of the samples after corrosion tests was examined using scanning electron microscopy and energy dispersive X-ray spectroscopy. Results showed that laser treated surface exhibited better corrosion resistance properties as compared to untreated surface. (orig.)

  20. High temperature corrosion of heat-resisting alloys by borosilicate melts containing simulated high level nuclear wastes

    In connection with the development of vitrified solidification process of high level liquid wastes (HLLW) by metallic vessel, the high temperature corrosion of some heat-resisting alloys, such as stainless steel, Incoloy and Inconel, were investigated with the molten borosilicate glass containing simulated HLLW in the temperature range of 1,000--1,2000C for 3--50 days. The concentration distributions of various constituents in the vicinity of the interface between the glass and the various metals were determined by means of EPMA. In the case of stainless steel, the general corrosion of alloys was observed without a protective layer. But in the case of both of Incoloy and Inconel, a chromium oxide layer was consequently formed between the glass and the metal, giving a protective film against general corrosion of alloys. When a MgCr2O4 layer on the chromium oxide layer and the alumina in alloy were, furthermore, formed, the corrosion of alloys became extremely depressed. The growth rate of the layer was controlled by chromium diffusion in alloy. The values of the effective diffusion coefficients D tilde sub(Cr) were approximately 1x10-10cm2/s at 1,1050C. (author)

  1. Effect of corroded surface layer on tensile properties of heat resisting alloys

    Tensile properties of corroded specimens were compared to those of aged specimens at room and high temperatures on Hastelloy X, Incolony 800 and 800H. The effects of corrosion environments (air and HTR-B helium), corrosion time, temperature, and shape/size were noted. Tensile strength could be quantitatively expressed in terms of the intergranular oxidation, irrespective of the variation of materials and corroded conditions. Ratio of the intergranular oxidation in specimens with various shape/size combination was successfully arranged by using the term of specific surface area. From the results described above, change in the tensile strength of components due to corrosion for various shape/size combinations can be predicted in terms of the intergranular oxidation and the specific surface area

  2. Effect of yttrium on the oxide scale adherence of pre-oxidized silicon-containing heat-resistant alloy

    Highlights: → AE experiment shows yttrium has a beneficial effect on the pre-oxidized HP40 alloy. → Yttrium facilitates the formation of internal oxide after 10 h of oxidation. → Internal oxide changes the rupture behaviour of the oxide scale. → Twins form in the internal oxide and improve the binding strength of the scale. - Abstract: This paper investigates the effect of the rare earth element yttrium on the rupture behaviour of the oxide scale on the silicon-containing heat-resistant alloy during cooling. After 10 h of oxidation, yttrium is found to facilitate the formation of internal oxides (silica) at the scale-matrix interface. Due to the twinning observed by scanning transmission electron microscopy (STEM) in silica, the critical strain value for the scale failure can be dramatically improved, and the formation of cracks at the scale-matrix interface is inhibited.

  3. Heat-resistant materials

    1997-01-01

    This handbook covers the complete spectrum of technology dealing with heat-resistant materials, including high-temperature characteristics, effects of processing and microstructure on high-temperature properties, materials selection guidelines for industrial applications, and life-assessment methods. Also included is information on comparative properties that allows the ranking of alloy performance, effects of processing and microstructure on high-temperature properties, high-temperature oxidation and corrosion-resistant coatings for superalloys, and design guidelines for applications involving creep and/or oxidation. Contents: General introduction (high-temperature materials characteristics, and mechanical and corrosion properties, and industrial applications); Properties of Ferrous Heat-Resistant Alloys (carbon, alloy, and stainless steels; alloy cast irons; and high alloy cast steels); Properties of superalloys (metallurgy and processing, mechanical and corrosion properties, degradation, and protective coa...

  4. Low-cycle fatigue of Type 347 stainless steel and Hastelloy alloy X in hydrogen gas and in air at elevated temperatures

    Jaske, C. E.; Rice, R. C.; Buchheit, R. D.; Roach, D. B.; Porfilio, T. L.

    1976-01-01

    An investigation was conducted to assess the low-cycle fatigue resistance of two alloys, Type 347 stainless steel and Hastelloy Alloy X, that were under consideration for use in nuclear-powered rocket vehicles. Constant-amplitude, strain-controlled fatigue tests were conducted under compressive strain cycling at a constant strain rate of 0.001/sec and at total axial strain ranges of 1.5, 3.0, and 5.0 %, in both laboratory-air and low-pressure hydrogen-gas environments at temperatures from 538 to 871 C. Specimens were obtained from three heats of Type 347 stainless steel bar and two heats of Hastelloy Alloy X. The tensile properties of each heat were determined at 21, 538, 649, and 760 C. The continuous cycling fatigue resistance was determined for each heat at temperatures of 538, 760, and 871 C. The Type 347 stainless steel exhibited equal or superior fatigue resistance to the Hastelloy Alloy X at all conditions of this study.

  5. 9-12% Cr heat resistant steels. Alloy design, TEM characterisation of microstructure evolution and creep response at 650 C

    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 evolution and creep response was established. All crept samples showed a significant increase of sub-grain size and a reduction of the dislocation density. Hot deformed samples showed better creep strength than non hot-deformed samples, due to homogenisation of the microstructure. The tempering temperature affected the dislocation density and the sub-grain sizes, influencing the creep behaviour. 9% Cr alloys were designed supported by ThermoCalc. Two sets of alloys were produced: 9% Cr alloys with 0.1 % C and 0.05% C and 9% Cr alloys containing ∝ 0.03% Ti again with 0.1% C and 0.05% C (always wt%). Microstructure investigations showed good agreement with the predicted phases of the thermodynamic modeling. The volume fraction of precipitated M{sub 23}C{sub 6} carbides is directly related to the carbon content of the alloys. Hardening of the Ti-containing alloys by precipitation of fine dispersed Ti-based MX particles was achieved. The precipitation of these carbides was limited to the austenisation and tempering treatment used. The microstructure evolution (sub-grain and particle size) during creep at 650 C / 100MPa was investigated by STEM-HAADF. The sub-grain size evolution and the coarsening of precipitates (MX carbonitrides, M{sub 23}C{sub 6} and Laves phase) were more pronounced for Ti-containing alloys. 9Cr alloys without Ti and with low carbon content presented the highest creep strength of all investigated alloys.

  6. 9-12% Cr heat resistant steels. Alloy design, TEM characterisation of microstructure evolution and creep response at 650 C

    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 M23C6 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 M23C6 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 evolution and creep response was established. All crept samples showed a significant increase of sub-grain size and a reduction of the dislocation density. Hot deformed samples showed better creep strength than non hot-deformed samples, due to homogenisation of the microstructure. The tempering temperature affected the dislocation density and the sub-grain sizes, influencing the creep behaviour. 9% Cr alloys were designed supported by ThermoCalc. Two sets of alloys were produced: 9% Cr alloys with 0.1 % C and 0.05% C and 9% Cr alloys containing ∝ 0.03% Ti again with 0.1% C and 0.05% C (always wt%). Microstructure investigations showed good agreement with the predicted phases of the thermodynamic modeling. The volume fraction of precipitated M23C6 carbides is directly related to the carbon content of the alloys. Hardening of the Ti-containing alloys by precipitation of fine dispersed Ti-based MX particles was achieved. The precipitation of these carbides was limited to the austenisation and tempering treatment used. The microstructure evolution (sub-grain and particle size) during creep at 650 C / 100MPa was investigated by STEM-HAADF. The sub-grain size evolution and the coarsening of precipitates (MX carbonitrides, M23C6 and Laves phase) were more pronounced for Ti-containing alloys. 9Cr alloys without Ti and with low carbon content presented the highest creep strength of all investigated alloys.

  7. Evaluation on materials performance of Hastelloy Alloy XR for HTTR uses-5 (Creep properties of base metal and weldment in air)

    Creep properties of weldment made from Hastelloy Alloy XR base metals and filler metals for the High Temperature Engineering Test Reactor (HTTR) components were examined by means of creep and creep rupture tests at 900 and 950degC in air. The results obtained are as follows: creep rupture strength was nearly equal or higher than that of Hastelloy Alloy XR master curve and was much higher than design creep rupture strength [SR]. Furthermore, creep rupture strength and ductility of the present filler metal was in the data band in comparison with those of the previous filler metals. It is concluded from these reasons that this filler metal has fully favorable properties for HTTR uses. (author)

  8. Optimization of composition of heat resistance granular alloy and its experimental study

    The optimization of EhP975P alloy composition has been carried out with the aim to avoid formation of topologically close packed embritting phases and to ensure high ductility. The alloy suggested has a wide range of homogeneity. This makes it possible to conduct its compacting and heat treatment using standard equipment. Compared to the former composition a new alloy possesses elevated plasticity and is not notch sensitive during long-term rupture strength tests

  9. New low alloy heat resistant ferritic steels T/P23 and T/P24 for power plant application

    Higher efficiencies and increasing requirements for reduced emissions can only be met by fossil fired power plants through a further increase of steam temperature and pressure. Material development has mainly been focussed on high heat resistant martensitic 9-12% Cr steels. Ensuring higher steam parameters, however, has also lead to increasing requirements for tube steels in water walls, which can no longer be fulfilled with standard low alloy ferritic steels like 13CrMo4-4 (T12). The paper describes the properties of the newly developed steels T23 and T24. It also will be shown that they can have benefits by using them as P23/P24 for piping, especially for the refurbishment of old plants

  10. Improvement of creep strength of TIG welded hastelloy X alloy joint

    The creep strength of the TIG welded joints of Hastelloy X is sometimes weaker than that of the parent material. Especially in the internal pressure creep test using cylindrical test pieces, this phenomenon appears conspicuously. This is because in the case of the cylinders having circumferential joints, the rupture time becomes short due to the enhanced creep phenomenon, in which the welded metal is pulled by the parent material having large creep rate, and its creep rate increases. In order to improve this defect, it was attempted to improve the creep strength of the welded metal by adding B, Zr and rare earth elements to the welding rods. As the result, by adding several tens ppm of B, the weldability was not harmed, and the remarkable effect of improvement was observed. Also it was found that rare earth elements were considerably effective. In the cylindrical test pieces having joints, for which these improved welding rods were used, the joints which broke in the parent material were able to be obtained. As for the case of the cylindrical test pieces having circumferential and longitudinal joints, the comparison of creep strength was carried out, but nearly the same strength was shown, and it was proposed to regard the circumferential joints as important similarly to the longitudinal joints. (Kako, I.)

  11. Improving effect of rare earth elements on the high temperature oxidation resistance of sintered heat resisting-alloys

    Nagai, Hiroshi

    1987-11-25

    In order to clarify the improving effect of rare earth elements on the oxidation resistance, various additive methods, i. e. metallic addition, dispersion of oxide and superficial application of oxide particles were investigated. The influence of rare earth elements on the ionic defect structure of Cr/sub 2/O/sub 3/ was also studied. Oxide weight increase and film exfoliation rate were investigated on Ni-20Cr alloy at conditions of atmospheric oxidation, 1273K and rare earth metallic addition, and effects on oxidation rate lowering and film exfoliation rate reduction due to the addition of rare earth elements were verified. In case of oxide dispersion, much larger effect than metallic addition could be verified for Fe-20Cr, Ni-20Cr, Ni-15Cr and sintered IN-100. Similar results were obtained in case of superficial application on the sintered Fe-20Cr alloy. Two improving effects of rare earth elements on lowering oxidation rate and suppressing the scale spalling on heat resistant alloys were much stronger than those of other reactive elements. (8 figs, 1 photo, 37 refs)

  12. Influence of loading frequency and cycle shape on crack resistance in heat resisting nickel alloy

    A study is made into the influence of loading frequency and cycle shape on fracture properties of granular nickel alloy EhP741NP at 650 deg C. It is shown that a loading frequency increase from 0.1 to 10 Hz results in a growth of crack resistance factor and in a decrease of crack growth rate and a coefficient of cycle asymmetry. The loading cyclicity is found to be a predominant factor of damageing which defines the time to fracture in the alloy EhP741NP. 5 refs.; 3 figs

  13. Die-casting capabilities of heat resistant Mg-Al-Ca alloys

    Kim, J.M.; Park, B.K.; Jun, J.H.; Kim, K.T.; Jung, W.J. [Advanced Materials Development Center, Korea Inst. of Industrial Technology, Yeonsu-Ku, Incheon (Korea)

    2005-07-01

    Various amounts of Ca were added to AZ91D magnesium alloy, and their effects on the die-casting abilities were investigated. It was observed that fluidity as die filling ability tends to decrease by Ca additions except for about 2%Ca. This reduction of fluidity by Ca was more significant at high superheats probably due to the high affinity between Ca and oxygen. Contrary to expectation, hot cracking resistance was found to increase by Ca additions. High Ca alloys showed some die-sticking tendency. However, the tendency was not observed below 2%Ca. (orig.)

  14. Tensile deformation behavior of spray-deposited FVS0812 heat-resistant aluminum alloy sheet at elevated temperatures

    The tensile deformation behavior of spray deposited FVS0812 heat-resistant aluminum alloy sheet was studied by uniaxial tension tests at temperatures ranging from 250 deg. C to 450 deg. C and strain rates from 0.001 to 0.1 s-1. The associated fracture surfaces were examined by scanning electron microscopy (SEM). The results show that the degree of work-hardening increases with decreasing temperature, and exhibits a small decrease with increasing strain rate; the strain rate sensitivity exponent increases with increasing temperature. The flow stress increases with increasing strain rate but decreases with increasing temperature. The total elongations to fracture increase not only with increasing temperature, but also with increasing strain rate, which is in marked contrast with the normal inverse dependence of elongation on the strain rate exhibited by conventional aluminum alloy sheets. The SEM fracture analysis indicates that the dependence of elongation on the strain rate may be due to the presence of a transition from plastic instability at lower strain rates to stable deformation at higher strain rates for fine-grained materials produced by spray deposition

  15. Tungsten determination in heat resistant nickel-base-alloys by the method of atomic absorption

    A method of atomic absorption was developed. It allows for the tungsten to be determined in heatresistant nickel-base-alloys within the range 0.01 to 7%. It consists in precipitating tungsten acid in the presence of alkaloids with its following decomposition by hydrofluoric acid in the teflon bomb. (author)

  16. Various properties of Tempaloy 800 H heat resistant and corrosion resistant high alloy steel tubes

    Kamemura, Yoshiki; Settai, Yoshio; Murase, Sadahiko

    1982-11-01

    For the use in petroleum refining, petrochemistry, high temperature gas-cooled reactors, fast breeder reactors, nuclear fusion reactors and so on, high alloy steel and nickel-base superalloy have been examined. Nippon Kokan K.K. has established the production system for Tempaloy 800 H steel tubes, which are the high alloy steel tubes of 20 Cr-32 Ni-Al-Ti system corresponding to NCF 800 H in JIS. This material is more stable austenite as compared with ordinary austenitic stainless steel, accordingly it is excellent in structural stability, corrosion resistance, oxidation resistance, carburization resistance and strength at high temperature, and the workability and weldability also are good. The method of production, the chemical composition, mechanical properties, microstructure, high temperature strength, bending workability, grain boundary corrosion and weldability are reported. It was confirmed that the characteristics of these alloy steel tubes were very good. It is expected that the demand of high alloy steel tubes of this kind will increase hereafter, therefore efforts are exerted further to improve the quality and performance so as to meet the request of users, by sufficiently grasping the severe environment of use.

  17. Various properties of Tempaloy 800 H heat resistant and corrosion resistant high alloy steel tubes

    For the use in petroleum refining, petrochemistry, high temperature gas-cooled reactors, fast breeder reactors, nuclear fusion reactors and so on, high alloy steel and nickel-base superalloy have been examined. Nippon Kokan K.K. has established the production system for Tempaloy 800 H steel tubes, which are the high alloy steel tubes of 20 Cr-32 Ni-Al-Ti system corresponding to NCF 800 H in JIS. This material is more stable austenite as compared with ordinary austenitic stainless steel, accordingly it is excellent in structural stability, corrosion resistance, oxidation resistance, carburization resistance and strength at high temperature, and the workability and weldability also are good. The method of production, the chemical composition, mechanical properties, microstructure, high temperature strength, bending workability, grain boundary corrosion and weldability are reported. It was confirmed that the characteristics of these alloy steel tubes were very good. It is expected that the demand of high alloy steel tubes of this kind will increase hereafter, therefore efforts are exerted further to improve the quality and performance so as to meet the request of users, by sufficiently grasping the severe environment of use. (Kako, I.)

  18. Weldability and weld performance of a special grade Hastelloy XR modified for VHTR

    The bead welding test by EB welding and the trans-varestraint test by TIG welding were carried out, and the characteristics of the defects arising in welded parts were clarified, also the range of the correct welding parameters was determined. It was shown that the results obtained were almost similar to those of Hastelloy X. The corrosion test on the welded metal in helium atmosphere was performed, and the weight change, internal oxidation, altered layer and so on were investigated. As the results, it was clarified that the welded metal by EB and TIG weldings showed the similar properties to the parent metal, and was superior to Hastelloy X. As for the creep strength, the creep strength as the joints was evaluated on the basis of respective properties of the parent metal and the welded metal, and it was clarified that the EB joints were superior to the TIG joints. Hastelloy X is the candidate heat-resistant alloy for multi-purpose, high temperature gas-cooled reactors, and it is relatively stable against the effect of impurities in high temperature helium. In order to improve its corrosion resistance further, Japan Atomic Energy Research Institute has developed Hastelloy XR by increasing Mn content to improve surface film protection, reducing Al and Ti to prevent local oxidation, and reduced Co in view of induced radioactivity. (Kako, I.)

  19. Selection of canister materials: electrochemical corrosion tests of HASTELLOY C4 and other Ni-Cr(-Mo) alloys in chloride containing solutions

    Several Ni-Cr(-Mo) alloys (HASTELLOY C4, INCONEL 625, SANICRO 28, INCOLOY 825, INCONEL 690) were tested by electrochemical methods to characterize their corrosion behaviour in chloride containing solutions at various temperatures and pH-values in respect to their application as canister materials for final radioactive waste storage. Especially, HASTELLOY C4 which proved to have the highest corrosion resistance of all tested alloys was tested by the following electrochemical methods: (1) Poteniodynamic measurements to determine the characteristic potentials, passive current densities and critical pitting potentials. (2) Potentiostatic measurements in order to evaluate the duration of the incubation period at various potentials. (3) Galvanostatic measurements in order to characterize critical pitting potentials. As electrolyte 1 m H2SO4 was used, as parameters temperature, chloride content and pH-value were varied. Variation of temperature gives the following results: an increase in temperature leads to an increase of the critical passivation current density, the passive potential bandwidth decreases slightly and the passive current density increases with rising temperature. The addition of different chloride contents to the H2SO4 solution shows the following effects: the critical passivation current density and the passive current density increase with increasing chloride concentration and both, the critical pitting potentials and the pitting nucleation potentials, shift towards negative values. As third parameter the pH-value was varied. As expected, an increase of the pH-value extends the passive region to more negative values, the passive current density decreases. The variation of the pH-value does not affect the critical pitting potential. All tested alloys showed a clearly limited resistance against pitting corrosion phenomena. However, the best corrosion behaviour is shown by HASTELLOY C4, which has of all tested alloys the lowest passivation current density and the largest potential region with protection against local corrosion phenomena. (author)

  20. Influence of coating on the properties of heat resistant gas turbine alloys. Pt. 2. Microstructures

    Sachova, E.; Hougardy, H.P.

    1988-10-01

    Differences in the creep behaviour of some Ni base alloys were interpreted by a metallographic examination of broken specimens of a creep rupture test. If the fracture of uncoated specimens is initiated by an oxidation from the surface, by coating the time until rupture is elongated. If the fracture of uncoated specimens is unsensitive to an oxidation from the surface, there is no influence of a coating except one melt of the alloy IN-792 coated with RT 22. Improvements or deteriorations in creep resistance of coated specimens compared with uncoated mainly are caused by the heat treatments during or after coating. Different casting techniques influence the orientation of dendrites and size, position and arrangement of pores which partly have a decisive influence on the creep behaviour. Differences in creep limits up to a factor of 2 in time in general could not be interpreted by the metallographic observations used.

  1. Phase stability of heat resistant nickel Ni-Al-Cr-W-Ta-Mo alloy single crystals

    A study into the microstructure and phase transition temperatures in casted single crystals of a nickel base Ni-Al-Cr-W-Ta-Mo system alloy was carried out. A concentration dependence of ?-phase volume fraction and a position of (?+?')/(?+?'+?) phase boundary in the system studied are analytically estimated. This estimation permits forecasting ?-phase precipitation under actual condition of monocrystal growth by directional crystallization. 13 refs.; 4 figs.; 3 tabs

  2. Behaviour of selected heat resistant nickel-base alloys for steam turbine bolting

    The objective of the project was to optimize nickel-base turbine bolting by different heat treatments. The aim was to obtain the best comprise of the relevant bolting properties such as creep and relaxation strength, notch-rupture insensitivity, contraction and stress corrosion cracking-intensitivity. The investigations were carried out on the three creep-resistant nickel-base alloys NiCr 20Fe 25 TiAl (similar to Nimonic 70), NiCr 20 TiAl (corresponding to Nimonic 80A) and NiCr 15 TiAl (corresponding to Inconel X-750). (orig./MM) With 63 figs., 15 tabs

  3. Effect of the Fine-Grained Structure on the Fatigue Properties of the Heat-Resistant Nickel-Iron Alloy Inconel 718

    Mukhtarov, Sh. Kh.; Shakhov, R. V.

    2015-10-01

    It is well known that ultrafine-grained nickel alloys with average grain sizes d = 0.1-1 μm possess improved hot workability and can be used for superplastic forming or rolling. However, microstructure refinement can worsen some performance characteristics of the alloy, for example, heat-resistant or fatigue properties. In the present work, fatigue characteristics of the fine-grained alloy Inconel 718 are investigated. Ultrafine-grained alloys with average grain sizes d = 0.1-1 μm were manufactured by multiple forging with stage-by-stage deformation temperature decrease. During standard heat treatment of the alloy performed to obtain the desired properties, the γ-grain size was controlled by precipitations of δ-phase particles along the boundaries. Results of low-cycle fatigue tests of the fine-grained alloy at room and elevated temperatures are compared with the properties of the coarse-grained alloy.

  4. High temperature strength of hastelloy XR electron beam weld metal

    As for the electron beam welded joints of Hastelloy XR, which is the heat resistant alloy for high temperature gas-cooled reactors, the tensile, creep rupture and low cycle fatigue characteristics at high temperature of the weld metal were determined, and compared with the parent material. As the result, it was found that the strength of the welded joint can be treated as nearly the same as that of the parent metal up to 900 deg C, while at 1000 deg C, the tensile strength and creep rupture strength become lower than those of the parent material, therefore the enough strength-design consideration is indispensable for the application at 1000 deg C. (Kako, I.)

  5. Effects of composite scale on high temperature oxidation resistance of Fe-Cr-Ni heat resistant alloy

    Wang Haitao

    2009-05-01

    Full Text Available Fe-Cr-Ni heat resistant alloys with aluminum and silicon addition, alone and in combination, were melted using an intermediate frequency induction furnace with a non-oxidation method. By the oxidation weight gain method, the oxidation resistances of the test alloys were determined at 1,200 C for 500 hours. According to the oxidation weight gains, the oxidation kinetic curves were plotted and the functions were regressed by the least squares method. The results show that the oxidation kinetic curves follow the power function of y = axb (a>0, 0

  6. High temperature diffusion induced liquid phase joining of a heat resistant alloy

    Transient liquid phase bonding (TLP) of a nickel base superalloy, Waspaloy, was performed to study the influence of holding time and temperature on the joint microstructure. Insufficient holding time for complete isothermal solidification of liquated insert caused formation of eutectic-type microconstituent along the joint centerline region in the alloy. In agreement with prediction by conventional TLP diffusion models, an increase in bonding temperature for a constant gap size, resulted in decrease in the time, tf, required to form a eutectic-free joint by complete isothermal solidification. However, a significant deviation from these models was observed in specimens bonded at and above 1175 deg. C. A reduction in isothermal solidification rate with increased temperature was observed in these specimens, such that a eutectic-free joint could not be achieved by holding for a time period that produced complete isothermal solidification at lower temperatures. Boron-rich particles were observed within the eutectic that formed in the joints prepared at the higher temperatures. An overriding effect of decrease in boron solubility relative to increase in its diffusivity with increase in temperature, is a plausible important factor responsible for the reduction in isothermal solidification rate at the higher bonding temperatures

  7. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000 C in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the boron content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000 to 900 C. The trend observed in the tests from 900 to 1000 C can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900 C plays the role of the protective barrier against the boron dissipation into the environment. (orig.)

  8. Creep rupture properties under varying load/temperature conditions on a nickel-base heat-resistant alloy strengthened by boron addition

    A series of constant load and temperature creep rupture tests and varying load and temperature creep rupture tests was carried out on Hastelloy XR whose boron content level is 60 mass ppm at 900 and 1000degC in order to examine the behavior of the alloy under varying load and temperature conditions. The life fraction rule completely fails in the prediction of the creep rupture life under varying load and temperature conditions though the rule shows good applicability for Hastelloy XR whose boron content level is below 10 mass ppm. The modified life fraction rule has been proposed based on the dependence of the creep rupture strength on the born content level of the alloy. The modified rule successfully predicts the creep rupture life under the test conditions from 1000degC to 900degC. The trend observed in the tests from 900degC to 1000degC can be qualitatively explained by the mechanism that the oxide film which is formed during the prior exposure to 900degC plays the role of the protective barrier against the boron dissipation into the environment. (author)

  9. Evaluation on materials performance of Hastelloy Alloy XR for the High Temperature Engineering Test reactor components. Weldability and high temperature strength properties

    Weldability and high temperature strength properties of Hastelloy Alloy XR were investigated in order to evaluate the materials performance of base metal and filler metal for the High Temperature Engineering Test Reactor (HTTR) uses. The weldability was examined by means of the chemical analysis in the deposited metals, optical microscopy, FISCO test, hardness measurements and bend test. The high temperature strength properties were investigated through tensile tests at R.T., 800, 900 and 950degC in air, and creep and creep rupture tests at 900 and 950degC in air. The results obtained by each test showed favorable performance. In particular, the bend test which is considered to be critical pass demonstrated low susceptibility to weld cracking through the optimization of B and C contents in the filler metal and by narrowing the groove. Creep rupture strength was nearly equal or higher than those of Hastelloy Alloy XR master curve and was much higher than design creep rupture strength [SR]. Therefore, it is concluded that weldability, tensile and creep properties with these base metals and filler metals for the HTTR components are entirely satisfactory. (author)

  10. Changes In Mechanical Properties Of Heat Resisting Alloy For A Satellite Propulsion System After A Nitriding Process

    Kagawa, Hideshi; Fujii, Go; Kajiwara, Kenichi; Kuroda, Daisuke; Suzuki, Takuya; Yamabe-Mitarai, Yoko; Murakami, Hideyuki; Ono, Yoshinori

    2012-07-01

    Haynes25 (L-605) is a common heat resistant alloy used in mono-propellant structures and screen materials for catalyst beds. The lifetime requirements for thrusters have expanded dramatically after studies conducted in the 1970s on mono-propellant materials used to extend the service life. The material design had long remained unchanged, and the L-605 was still used as thruster material due to its good heritage. However, some important incidents involving degradation were found during the test-unit break-up inspection following the thruster life tests. The Japanese research team focused on the L-605 degradations found on the catalyst bed screen mesh used for mono-propellant thruster and analysed the surface of the wire material and the cross- section of the wire screen mesh used in the life tests. The investigation showed that the degradation was caused by nitriding L-605 component elements. The team suggested that the brittle fracture was attributable to tungsten (W) carbides, which formed primarily in the grain boundaries, and chromium (Cr) nitride, which formed mainly in the parts in contact with the hot firing gas. The team also suggested the installation of a platinum coating on the material surface as a countermeasure L-605 nitric degradation. Inconel 625 is now selected as a mono-propellant structure material due to its marginal raw material characters and cost. The team believes that Inconel 625 does not form W carbides since it contains no tungsten component, but does contain Cr and Fe, which form nitrides easily. Therefore, the team agreed that for the Inconel 625, there was a need to evaluate changes in the microstructure and mechanical properties following exposure to hot nitrogen gases. This paper will describe these changes of Inconel 625.

  11. Influence of a simulated HTGR environment on the mechanical properties of a commercial Ni-Cr-Mo-Fe alloy (Hastelloy Alloy X)

    The influence of a simulated advanced-reactor helium environment, containing 500 μatm H2/50 μatm CH4/50 μatm CO/approx. 1 μatm H2O, on the mechanical properties of two heats of Hastelloy Alloy X is discussed. Simultaneous exposures in air and controlled-impurity helium at temperatures in the range of 6500 to 10000C for times of 3000 h or more were performed. A combination of tensile testing, Charpy V-notch impact toughness testing, and creep testing was used to study the effects of reactor helium/metal interactions on the mechanical behavior of this alloy. Carburization was identified as the primary corrosion phenomenon. Increasing exposure time and temperature were observed to increase the depth of carburization. The increase in carbon concentration in the carburized zone suppressed the additional formation of M6C, which is observed in air-aged specimens, and resulted in the precipitation of M23C6, a chromium-rich carbide variant. The precipitation of M23C6 in the carburized zone occurred primarily along grain and twin boundaries; however, matrix precipitation was also observed, the degree of which depended on exposure temperature. Strength and impact toughness properties were found to be controlled primarily by thermal aging reactions, with only a small effect related to the carburization. Although tensile and creep ductilities were decreased as a result of carburization, substantial ductility remained. Variation was observed between the two heats, the finer-grained heat appearing to be weaker in the high-temperature creep tests and also possibly more susceptible to a loss of creep strength as a result of carburization

  12. Forecast of heat resistance and plasticity of steels and alloys on the base of data on the solid solution state and fine structure

    In the case of 12KhM, 15KhM and 12Kh1MF chromium-molybdenum steels, thin or fine structure parameters (e.g. density of dislocations, phase composition, the proportion of alloying elements in a solid solution, size and quantity of carbides have been determined; their influence on the mechanic-al properties has been examined after functioning during 100 thousand hours within the temperature range of 510 to 565 deg C. It has been shown that the greatest influence on the long-term strength and the heat resistance of the steels being examined exert the proportion of molybdenum in the solid solution and the volume proportion of permithe. The strain capacity of the material is determined by the volumetric portion of the strengthening phase, which has been corroborated by the results of examining EI929 heat-resistant nickel alloy. The comparative evaluation of the calculated and experimental values of the plasticity of that alloy has been carried out

  13. Oxidation and creep tests of hastelloy-S in VHTR helium environment

    Hastelloy-S, developed by Cabot Corp. for the applications involving severe cyclic heating condition, was tested for its potential applicability to VHTRs as one of the structural alloys. It is said that the alloy has excellent microstructural stability, low thermal expansion and outstanding oxidation resistance. The corrosion test and creep test of the alloy-S were carried out in simulated VHTR helium environment, and the results were compared with those of Hastelloy-XR ehich is one of the candidate materials for VHTR structural components. The results obtained were as follows. The oxidation resistance of the alloy-S was better than that of the alloy-XR. The oxidation resistance was increased by lowering the Cr content and increasing the relative ratio of Mn to Cr in Ni-base alloys. Localized oxidation was observed in the alloy-S at grain boundaries due to the internal oxidation of Al contained in the alloy. The creep strength of the alloy-S was lower than that of the alloy-XR. The comparison of creep property was made between the as-received material and the material with coarse grains formed by heat treatment. From the results obtained so far, it was judged that the alloy-S has not sufficient capability to be substituted for the alloy-XR. (Kako, I.)

  14. XRF analysis on powders of nickel-based heat-resisting alloys by glass bead technique and matrix correction using theoretical alpha coefficients

    Study of XRF analysis on main components of powders of nickel-based heat-resisting alloys has been performed. Calibration curves were made using eight synthetic standard glass bead samples prepared from the standard solution of each element. Correction was made for the matrix effects by using theoretical alpha coefficients. A sample(0.20 g) was dissolved with a mixture of 5 ml hydrofluoric acid and 1 ml of nitric acid in a platinum crucible. The solution was dried and the residue was baked for 30 min at 500 deg C. It was fused with Li2B4O7(8.0 g) and Li2CO3(2.0 g) as a flux, and KI(0.02 g) as a removing additive in a Pt-5 %Au crucible at 1070 deg C for 5 min. Accuracies(σd) of the determined concentration for each element, especially for chromium, iron and tantalum, were improved by using the correction in comparison with uncorrected ones. The relative standard deviation(R.S.D.) for each element were in the range of 0.37 ∼ 1.98 % with the exception of iron(0.13 %, R.S.D. : 4.30) and zirconium (0.081 %, R.S.D. : 3.36). The determined concentration for powders of nickel-based heat-resisting alloys such as Astroloy, Rene 95, MA 6000 and so on, showed good agreement with those determined by chemical analysis. (author)

  15. Development of Simultaneous Corrosion Barrier and Optimized Microstructure in FeCrAl Heat-Resistant Alloy for Energy Applications. Part 1: The Protective Scale

    Pimentel, G.; Aranda, M. M.; Chao, J.; González-Carrasco, J. L.; Capdevila, C.

    2015-09-01

    Coarse-grained Fe-based oxide dispersion-strengthened (ODS) steels are a class of advanced materials for combined cycle gas turbine systems to deal with operating temperatures and pressures of around 1100°C and 15-30 bar in aggressive environments, which would increase biomass energy conversion efficiencies up to 45% and above. This two-part paper reports the possibility of the development of simultaneous corrosion barrier and optimized microstructure in a FeCrAl heat-resistant alloy for energy applications. The first part reports the mechanism of generating a dense, self-healing α-alumina layer by thermal oxidation, during a heat treatment that leads to a coarse-grained microstructure with a potential value for high-temperature creep resistance in a FeCrAl ODS ferritic alloy, which will be described in more detail in the second part.

  16. Effect of crystallization character of a casting nickel alloy type ZhS6 on its heat resistance

    Results of studies in long-term strength and ductility are presented for a ZhS6U casting alloy with an equiaxial and directed structure. It is established that directed crystallization of the alloy raises its strength characteristics

  17. On the mechanism of seandium influence on strength and heat resistance increase in Al-Mg alloys

    An attempt is made to study the strengthening nature in the Al-Ng-Sc alloy system. The problems of the temperature stability of the non-crystallized structure of the Al-6.5% Mg alloy and the nature of secondary extractions in these alloys caused by scandium presence, are studied. The alteration of the fluidity limit of the Al-6.5% Mg-Se alloys depending on the annealing temperature for various types of intermediate products is shown. Doping of the Al-6.5% Mg alloy with scandium brings about a considerable increase of strength properties, as a result of formation of the ScAl3 phase

  18. Etude expérimentale du soudage par laser YAG de l'alliage base nickel Hastelloy X Experimental study of YAG laser welding of nickel base alloy Hastelloy X

    Graneix Jérémie; Beguin Jean-Denis; Pardeilhan François; Masri Talal; Alexis Joël

    2013-01-01

    Le procédé de soudage laser YAG est envisagé pour remplacer le procédé de soudage TIG manuel pour la réalisation de pièces de turboréacteur en alliage nickel-chrome-molybdène Hastelloy X. Cette étude expérimentale a permis de définir un domaine de soudabilité de cet alliage répondant aux critères spécifiques du secteur aéronautique. The YAG laser welding process is contemplated to replace the manual TIG welding process for the production of parts of turbojet in Hastelloy X. This experimental...

  19. Intergranular Cracking Susceptibility of 2.25Cr Heat-Resistant Steels Depending on Alloying Elements and Impurities

    Sung, Hyun Je; Heo, Nam Hoe; Kim, Sung-Joon

    2016-05-01

    The intergranular cracking susceptibility of 2.25Cr heat-resistant steels increases with increasing bulk phosphorus content. This is due to the increase in phosphorus segregation concentration of prior austenite grain boundaries (PAGBs) and the prior austenite grain boundary/carbide interfaces (GCIs) with increasing bulk phosphorus content. Moreover, the susceptibility is higher in tungsten-added steels than the molybdenum-added steel. This is attributed to the higher driving force for carbide formation of tungsten which causes more active carbide formation in the tungsten-added steel, the consequent absence of the repulsive segregation between carbon and phosphorus, and the final higher phosphorus segregation concentration at the PAGBs and the GCIs. Additionally, the absence of sulfur segregation at the PAGBs and the GCIs of the molybdenum-added steel, which arises from the repulsive segregation between carbon and sulfur, acts as an additional factor which lowers the intergranular cracking susceptibility.

  20. Control method of purification system of helium coolant for suppressing decarburization of heat-resistant alloy used in very high temperature gas cooling reactors

    It is important to control the chemistry of the helium coolant used in high-temperature gas-cooled reactors (HTGRs). The effect of a decarburizing environment on the creep rupture properties tends to decrease the creep rupture life of the heat-resistant alloy used in heat exchangers. In this paper, we describe an active control method for the concentration of impurities using the existing helium purification system, which consists of a helium heater, a copper oxide trap (CuOT), a molecular sieve trap, a cold charcoal trap, and a bypass line. Analysis showed that the efficiency control of CuOT is effective in improving the decarburizing atmosphere. The efficiency control of CuOT increases the concentrations of carbon monoxide and hydrogen. It was found that both the enrichment of carbon monoxide suggested in previous studies and the enrichment of hydrogen are also effective in forming the carburizing atmosphere. (author)

  1. Influence of manganese and silicon on high temperature oxidation of nickel-base heat resistant alloys in simulated VHTR helium environment

    Roles of Ma and Si in Hastelloy alloy X were examined in terms of the high temperature oxidation behavior of several experimental heats at 10000C in flowing helium containing very small amounts of impurities. Both elements were found to have significant influence both on the steady state oxidation rates, evaluated as Cr consumption rate, and on the oxide film spallation resistance. In such a special environment, characterized by very low oxygen potential, the following effects were observed: 1) Within the range (max. 1.32 wt%) tested addition of Mn improved the oxidation resistance nearly propotionally to the increase of Mn content. The effect was interpreted in formation of the outer MnCr2O4 spinel oxide layer outside the inner Cr2O3 oxide layer. 2) Addition of Si caused the similar effect on the steady state oxidation rate to the maximum (1.02 wt%) amount tested. The degree of adherence of the protective oxide film, however, was maximized at around 0.3 wt%, above and below which spallation of oxide film tended to occur with either increasing or decreasing Si content. These two could be explained in formation and morphology of the Si oxide phase in the oxide and metal interface. (author)

  2. Creep property of hastelloy X and incoloy 800 in a helium environment

    To clarify the mechanism of the effect of helium environment on the creep properties of heat resistant alloys, relations of creep curves to the surface finish of test specimens, the development of creep cracks and oxidation kinetics etc. have been examined. Incoloy 800 at the temperature of 7500C indicates scarecely any environmental effect within the range of primary and secondary creep zones. Enhancement in the creep rate is noticed, however, at the tertiary creep zone under the helium environment. This finding is correlated to the fact that the crack, once initiated on the surface of the test specimen, propagates more easily because of the less oxidation under the helium environment. Importance of process control shall be emphasized for the manufacture of Hastelloy X since it has become clear that the effect of grain size on the creep strength is more pronounced than that of environment. (author)

  3. Corrosion performance of heat resistant alloys in Na{sub 2}SO{sub 4}-V{sub 2}O{sub 5} molten salts

    Gonzalez-Rodriguez, J.G. [Universidad Autonoma del Estado de Morelos, FCQI-CIICAP, Av. Universidad 1001, Col. Chamilpa, 62210-Cuernavaca, Mor. (Mexico)]. E-mail: ggonzalez@uaem.mx; Haro, S. [Universidad Autonoma de Zacatecas, Zacatecas (Mexico); Martinez-Villafane, A. [CIMAV, Miguel de Cervantes 120, Complejo Ind. Chih., Chihuahua (Mexico); Salinas-Bravo, V.M. [Instituto de Investigaciones Electricas, Cuernavaca, Mor. (Mexico); Porcayo-Calderon, J. [Instituto de Investigaciones Electricas, Cuernavaca, Mor. (Mexico)

    2006-11-05

    The corrosion resistant of three heat resistant alloys in molten vanadium pentoxide (V{sub 2}O{sub 5}), sodium sulfate (Na{sub 2}SO{sub 4}) and 80(mol%) V{sub 2}O{sub 5}-20Na{sub 2}SO{sub 4} has been evaluated using the weight loss technique. Materials included Fe-25Cr-35Ni-0.45C, Fe-35Cr-45Ni with 0.12 and 0.45C alloys. Temperatures included 600, 700 and 800 deg. C for V{sub 2}O{sub 5} and the 80V{sub 2}O{sub 5}-20Na{sub 2}SO{sub 4} mixture, and 800, 900 and 1000 deg. C for Na{sub 2}SO{sub 4}. The tests were supplemented by detailed electronic microscopy and microanalysis studies. In all cases, the least resistant alloy was the Fe-25Cr-35Ni-0.45C one whereas the most resistant was the Fe-35Cr-45Ni-0.12C one. The results are discussed in terms of the acidic dissolution of the external protective Cr{sub 2}O{sub 3}, Al{sub 2}O{sub 3} and SiO{sub 2} layers, by the salts and internal sulfidation.

  4. A study on the creep properties more over 700 C of advanced heat resistant carbon, nitrogen and cobalt free alloys

    Muneki, Seiichi; Okubo, Hiroshi; Abe, Fujio [National Institute for Materials Science (NIMS) (Japan)

    2008-07-01

    A new attempt has been demonstrated using carbon, nitrogen and cobalt free Fe-12Ni-5Cr-Mo alloys strengthened by Laves phase such as Fe{sub 2}Mo to achieve creep deformation at high temperatures and high stress levels. Creep resistance of Fe-12Ni-5Cr-5Mo-0.005B alloys remarkably increased at elevated temperatures over 700 C. As the transformation temperatures of A{sub c1} and A{sub c3} of these alloys indicated remarkably low, the microstructure of these alloys was reverted austenite during the creep test over 700 C. Creep properties were extremely improved more over 700 C by the addition of boron, which depends on the effect of retardation of the recovery process and that the suppression of recrystallization of these alloys. Creep life of the Fe-12Ni-5Cr-10Mo-0.2Ti-0.1Al-0.005B alloy was drastically extended from 13h at 700 C and 300MPa to 2,100h at 700 C and 200MPa. Creep resistance in the Fe-12Ni alloys depends on the unrecrystallized austenite structure and a fine and uniform distribution of precipitates during creep tests. And that long term stability of microstructure works on the DSS operation effectively in the USC power plant. (orig.)

  5. Effect of reactor irradiation on heat resistance of high nickel alloys of 03Kh20N45M4 type

    Kiselevskij, V.N.; Kovalev, V.V.; Parshin, A.M.; Yaroshevich, V.D.; Kozhevnikov, O.A.; Lapin, A.N. (AN Ukrainskoj SSR, Kiev. Inst. Problem Prochnosti)

    1983-07-01

    The results are presented for intra-reactor studies of creep, long-term strength and plasticity of two modifications of 03Kh20N45M4 alloys in a 823-1023 K temperature range. The obtained characteristics are compared with the data for 0Kh16N15M3B steel. It is shown that the alloys possess higher characteristics of high-temperature strength as compared with the steel.

  6. Chloride corrosion resistance of EhP539 and EhP99 heat resistant nickel alloys

    The effect of temperature and time on chloride corrosion resistance in the ternary eutectics (MgCl2-KCl-NaCl) of industrial alloys on the EhP539 and EhP99 nickel basis is studied. It is shown, that the corrosion of the above alloys at the temperature of 500-900 grad C has primarily intercrystalline character and proceeds by two-three orders faster as compared to usual high-temperature oxidation

  7. Effect of composition of residual gases in vacuum on the Nb-Zr-C alloy heat resistance

    Studied is the effect of residual gases in oil vacuum obtained with the aid of a diffusion vapour-oil pump and oilless vacuum obtained with the aid of magneto-discharge diode pumps, the effect being produced on mechanical properties and the structure of the Nb-1%-Zr-1% C alloy. Long-period ageing at 900 deg C in oilless vacuum head to increasing alloy strength at room temperature. The samples aged in oil vacuum exhibit the higher strength and creep resistance at 900 and 1000 deg C

  8. Characterization of oxide layers of heat-resisting alloys in oxidizing and oxidizing/sulfidizing atmospheres by deuterium permeation measurement

    Deuterium permeation measurements are suitable to characterize the integrity of layers, which are preoxidized or in-situ oxidized on high temperature alloys. The permeation through metal alloys with a growing oxidized layer is described by a model with a time dependence of the permeation flux related to the growth of the oxide layer. The behaviour of the layers, which are oxidized at different oxidizing atmospheres, are investigated in this work. By permeation test, parabolic rate constants, impeding factors, as well as permeability, diffusivity and the solubility of deuterium for the oxide layers are obtained. The measurement are continued in sulfidizing atmosphere for testing such layers as corrosion barrier. In correlation with microstructural post examinations it is found that permeation measurement can be utilized as a method for investigating high-temperature corrosion. (orig.)

  9. Characterization of grain boundaries by fractal geometry and creep-rupture properties of heat-resistant alloys. [21-4N, HS-21, L-605, Inconel X-750, Inconel 751

    Tanaka, Manabu; Iizuka, Hiroshi (Akita Univ. (Japan). Dept. of Mechanical Engineering for Production)

    1991-06-01

    There is a certain 'self-similarity' between the parts and the whole of a microstructure in metallic materials, although the microstructures are generally complicated and irregular in nature. Serrated grain boundaries which are composed of irregular ledges and steps are effective in improving the high-temperature strength of heat-resistent alloys. There are some differences in the 'degree' (ruggedness) among the grain boundaries in heat-resistant alloys, depending on alloy composition and heat treatments. In this study, serrated grain boundaries are characterized by estimating the fractal dimension, and the relation between the increase of the fractal dimension of grain boundaries and the improvement of creep-rupture properties by serrated grain boundaries is discussed. (orig.).

  10. Influence of coating on the properties of heat resistant gas turbine alloys. Pt. 1. Creep-rupture behaviour

    Ebeling, W.; Granacher, J.; Kloos, K.H.; Hagedorn, K.E.

    1988-10-01

    The influence of coatings and coating thermal cycles on the creep and creep-rupture behaviour of several nickel based gas turbine blade and vane alloys was evaluated. As a result of creep-rupture tests, the scatter bands of the rupture stress and of the stress to reach 0.2% plastic strain show in comparison to the uncoated materials decreased mean values and even more decreased lower bound values. At an austenitic steel for exhaust valves, no influence of coating was observed.

  11. Effect of mechanical surface treatment on oxidation and carburization of some austenitic heat resisting alloys in the simulated HTGR helium environment

    Influence of mechanical surface finishing on corrosion was studied with some austenitic heat resisting alloys exposed to the simulated HTGR helium environment. The exposure tests were made at 900 and 10000C for 500 and 1500h. Contrary to the prediction based on the trend of some conventional experimental results on the oxidation of cold worked material at comparatively low temperatures, severe cold working, e.g. shot-blasting, was found to accelerate oxidation and carburization. Although, in some cases, moderate surface grinding showed results almost comparable to the surface abraded with fine emery papers, most mechanical surface finishing were recognized as to promote oxidation and carburization at 900 and 10000C in the simulated HTGR helium. The oxide film formed on the ground or shot-blasted specimen tended to spall more easily during cooling after isothermal exposure at 10000C. Based on the metallographic observation mechanisms of the acceleration of oxidation and carburization was discussed. The surface cold work was considered to cause not only enhanced chromium diffusion to the surface but also considerable degree of inhomogeneity of the degree of working in the microscopic scale, resulting in rather rapid oxide build-up and spallation. Some of the surface finishing in practice with severe cold working, thus, were concluded to be harmful to the integrity of HTGR structural components. (author)

  12. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy; Influencia de los parametros de soldeo fuerte en la microestructura y propiedades mecanicas de la union de la aleacion base niquel Hastelloy B2

    Sotelo, J. C.; Gonzalez, M.; Porto, E.

    2014-07-01

    A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes. (Author)

  13. Tungsten powder alloys with carbide hardening as materials for reinforcing fibres in heat resistant composite materials. Communication 1.Manufacture of powder tungsten carbide-hardened alloys

    Factors affecting the possibility of stabilization in tungsten powder alloys of high-melting hardening interstitial phases (carbides, borides and nitrides of 4 group metals) are considered: presence of oxygen from the atmosphere and that asorbed on the surface of powder particles within W-MeC(MeB2, MeN) system; temperature of sintering occurrence of interstitial elements or phases interacting with oxygen more actively that the phase (HfC) that should be stabilized in the system. Measures allowing to prepare tungsten powder alloys using standard process equipment are suggested

  14. Study on the creep constitutive equation of Hastelloy X, (1)

    In order to carry out the structural design of high temperature pipings, intermediate heat exchangers and isolating valves for a multipurpose high temperature gas-cooled reactor, in which coolant temperature reaches 1000 deg C, the creep characteristics of Hastelloy X used as the heat resistant material must be clarified. In addition to usual creep rupture life and the time to reach a specified creep strain, the dependence of creep strain curves on time, temperature and stress must be determined and expressed with equations. Therefore, using the creep data of Hastelloy X given in the literatures, the creep constitutive equation was made. Since the creep strain curves under the same test condition were different according to heats, the sensitivity analysis of the creep constitutive equation was performed. The form of the creep constitutive equation was determined to be Garofalo type. The result of the sensitivity analysis is reported. (Kako, I.)

  15. Fundamental studies on electron beam welding of heat-resistant superalloys for nuclear plants, (1)

    The basic investigation and research on the multi-purpose utilization of nuclear reactors have been carried out as the national project. The equipments for high temperature gas-cooled reactors are exposed to severe conditions in helium atmosphere of 1000 deg C, therefore the use of heat-resistant alloys such as Hastelloy, Inconel and Incoloy has been examined. The electron beam welding recently expanding the fields of application has excellent properties, such as the energy density is very high, the power output can be controlled freely as occasion arises, deep penetration can be obtained with small heat input, welding of high precision is feasible because the width of weld is narrow and the distortion due to the welding is small, and the weld of good quality can be obtained as the welding is carried out in vacuum. However, when the welding conditions are improper, the defects peculiar to electron beam welding arise, such as porosity, cold shut, spike phenomenon, and cracking due to welding. In this study, the characteristics of weld beads of respective heat-resistant alloys, especially the penetration mode and the properties of defects, were investigated by changing the parameters of electron beam welding, and the correlation among these was discussed. The range of proper welding conditions was set up for respective materials. Moreover, the correlation among the cracking susceptibility due to electron beam welding, the high temperature ductility of materials and the results of Trans-Varestraint test was investigated, and these testing methods are very useful for the evaluation of cracking susceptibility. (Kako, I.)

  16. Grain growth in heat resisting austenitic steels

    Denisova, I.K.; Zakharov, V.N.; Karpova, N.M.; Farber, V.M.

    1985-01-01

    A study was made on kinetics of grain growth in steels of 37Kh12N8G8 type alloyed by V, Nb, Ti, Mo, W. It was concluded that the nature of carbide phase and kinetics of its dissolution in heat resisting austenitic steels dictate steel tendency to grain growth. At the same time decrease of diffusion mobility of atoms in steel matrix during its alloying by titanium aid tungsten results in sufficient decrease of the tendency to grain growth and variation in grain size.

  17. Influence of temperature, environment, and thermal aging on the continuous cycle fatigue behavior of Hastelloy X and Inconel 617

    Results are presented for strain-controlled fatigue and tensile tests for two nickel-base, solution-hardened reference structural alloys for use in several High-Temperature Gas-Cooled Reactor (HTGR) concepts. These alloys, Hastelloy X and Inconel 617, were tested from room temperature to 8710C in air and impure helium. Materials were tested in both the solution-annealed and the preaged conditios, in which aging consisted of isothermal exposure at one of several temperatures for periods of up to 20,000 h. Comparisons are given between the strain-controlled fatigue lives of these and several other commonly used alloys, all tested at 5380C. An analysis is also presented of the continuous cycle fatigue data obtained from room temperature to 4270C for Hastelloy G, Hastelloy X, Hastelloy C-276, and Hastelloy C-4, an effort undertaken in support of ASME code development

  18. Application of Hastelloy X in Gas-Cooled Reactor Systems

    Brinkman, C. R.; Rittenhouse, P. L.; Corwin, W.R.; Strizak, J.P.; Lystrup, Aage; DiStefano, J.R.

    1976-01-01

    Hastelloy X, an Ni--Cr--Fe--Mo alloy, may be an important structural alloy for components of gas-cooled reactor systems. Expected applications of this alloy in the High-Temperature Gas-Cooled Reactor (HTGR) are discussed, and the development of interim mechanical properties and supporting data are...... environments that are expected to be prototypic of HTGR operating conditions, it was necessary to construct special environmental test systems. Details of construction and operating parameters are described. Interim results from tests designed to determine the above properties are presented. To date a fairly...

  19. Weldability of superalloys Hastelloy X by Yb : YAG laser

    Graneix, Jérémie; Béguin, Jean-Denis; ALEXIS, Joël; Masri, Talal

    2015-01-01

    Requirements of aircraft parts welded becoming increasingly severe especially in terms of reproducibility of geometry and metallurgical grade of weld bead; laser welding is a viable method of assembly to meet these new demands by its automation to replace longer term the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X alloy by the butt welding process Nd: YAG laser. To identify influential parameters of the welding process (laser power, ...

  20. Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

    SAE Aerospace Standards. London

    2012-01-01

    Nickel Alloy, Corrosion and Heat-Resistant, Sheet, Strip, and Plate 72Ni - 15.5Cr - 0.95 (Cb (Nb) + Ta) - 2.5Ti - 0.70Al - 7.0Fe Consumable Electrode, Remelted or Vacuum Induction Melted, Solution Heat Treated, Precipitation-Hardenable

  1. High temperature low-cycle fatigue strength of Hastelloy-XR

    This paper describes the low-cycle fatigue and creep-fatigue interaction properties of Hastelloy-XR in air and helium containing a small quantity of impurity gas. All tests at temperatures of 700, 800, 900 and 1000 deg. C are carried out at the strain rate of 0.1 and 0.01%/sec under the control of axial strain. Wave forms are triangular for continuous cycling tests and trapezoidal for tension hold time tests. The test results are compared with the fatigue property of Hastelloy-X which is the original alloy of Hastelloy-XR. The applicability of linear damage rule in ASME Code Case N-47 is discussed about creep-fatigue interaction property of Hastelloy-XR in High Temperature Gas-Cooled Reactor's temperature region. (author). 6 refs, 7 figs, 2 tabs

  2. Development of Simultaneous Corrosion Barrier and Optimized Microstructure in FeCrAl Heat-Resistant Alloy for Energy Applications. Part II: The Optimized Creep-Resistant Microstructure

    Pimentel, G.; Aranda, M. M.; Chao, J.; González-Carrasco, J. L.; Capdevila, C.

    2015-09-01

    The first part of this two-part study reported the possibility of simultaneously generating a dense, self-healing α-alumina layer by thermal oxidation and a coarse-grained microstructure with a potential goodness for high-temperature creep resistance in a FeCrAl oxide dispersion-strengthened ferritic alloy that was cold deformed after hot rolling and extrusion. In this second part, the factors affecting the formation of the coarse-grained microstructure such as strain gradients induced during the rolling process are analyzed. It is concluded that larger strain gradients lead to more refined and more isotropic grain structures.

  3. The flow behavior modeling of as-extruded 3Cr20Ni10W2 austenitic heat-resistant alloy at elevated temperatures considering the effect of strain

    Guo-Zheng, Quan; Yuan-Ping, Mao; Chun-Tang, Yu; Wen-Quan, Lv; Jie, Zhou.

    2014-04-01

    Full Text Available In order to investigate the compressive deformation behavior of 3Cr20Ni10W2 alloy, a series of isothermal upsetting experiments were carried out in the temperature range of 1203-1403 K and strain rate range of 0.01-10 s-1 on a Gleeble-1500 thermo-mechanical simulator. The results indicate that the f [...] low stress initially increases to a peak value and then decreases gradually to a steady state. The characteristics of the curves are determined by the interaction of work hardening (WH), dynamic recovery (DRV) and dynamic recrystallization (DRX). The flow stress decreases with increasing temperature and decreasing strain rate. The relationship between microstructure and processing parameters is discussed to give an insight into the hot deformation behavior of 3Cr20Ni10W2 alloy. Then, by regression analysis for constitutive equation, material constants (n, ?, ?, A and Q) were calculated for the peak stress. Further, the constitutive equation along the flow curve was developed by utilizing an eighth order polynomial of strain for variable coefficients (including n, ?, A and Q). The validity of the developed constitutive equation incorporating the influence of strain was verified through comparing the experimental and predicted data by using standard statistical parameters such as correlation coefficient (R) and average absolute relative error (AARE) that are 0.995 and 4.08% respectively.

  4. The new alloy Thermon 4972 (NiCr22W12Fe) for high temperature components of gas-cooled reactors

    A new heat resistant Fe-Ni-Cr-W alloy - Thermon 4972 - was developed within the scope of the prototype nuclear process plant project. This new alloy not only shows mechanical properties and creep rupture properties similar to those of the nickel-based alloy Inconel 617 but in addition, the new alloy forms protective oxide layers in atmospheres with very low O2 partial pressures. Experimental test results carried out in so called PNP-helium for durations up to 2000 h in the temperature range of 750 and 950 deg. C are compared with those of the alloy Inconel 617. Furthermore the mechanical properties of these two alloys as also the alloys Hastelloy X and Incoloy 800 H have been compared. (author). 5 refs, 18 figs, 2 tabs

  5. Kinetics of evaporation and ablation of goods made from heat-resistant alloys with protective coatings under irradiation with high-power ion beams

    The kinetics of ablation of the surface layers of the specimens and gas-turbine engine (GTE) vanes made from the Ti- and Ni-based alloys with erosion-resistant coatings under the action of power pulse ion beams (PPIB) at different pulse current density has been studied. The basics of ecology-pure ion-beam technologies of repairing GTE vanes with different protective coatings are developed. It is shown that a powerful ion beam of millimicrosecond duration is quite an efficient tool for repairing compressor blades and a turbine with protective coatings. PPIB application makes it possible to remove the surface layers of 0.04 (TiSiB) up to 1 μm (ZrN) thickness for one impulse

  6. Crack propagation in Hastelloy X

    The fatigue and creep crack growth rates of Hastelloy X were examined both in air and impure helium. Creep crack growth rate is higher in air and impure helium at 6500C. Initial creep crack growth from the original sharp fatigue crack is by an intergranular mode of fracture. As the cracking accelerates at higher stress intensities, growth is by a mixed mode of both intergranular and transgranular fracture. Fatigue crack growth rate increases with increasing temperature and decreasing frequency for the range of stress intensities reported in the literature and is lower in impure helium than in air

  7. Application of Hastelloy X in gas-cooled reactor systems

    Brinkman, C.R.; Rittenhouse, P.L.; Corwin, W.R.; Strizak, J.P.; Lystrup, A.; DiStefano, J.R.

    1976-10-01

    Hastelloy X, an Ni--Cr--Fe--Mo alloy, may be an important structural alloy for components of gas-cooled reactor systems. Expected applications of this alloy in the High-Temperature Gas-Cooled Reactor (HTGR) are discussed, and the development of interim mechanical properties and supporting data are reported. Properties of concern include tensile, creep, creep-rupture, fatigue, creep-fatigue interaction, subcritical crack growth, thermal stability, and the influence of helium environments with controlled amounts of impurities on these properties. In order to develop these properties in helium environments that are expected to be prototypic of HTGR operating conditions, it was necessary to construct special environmental test systems. Details of construction and operating parameters are described. Interim results from tests designed to determine the above properties are presented. To date a fairly extensive amount of information has been generated on this material at Oak Ridge National Laboratory and elsewhere concerning behavior in air, which is reviewed. However, only limited data are available from tests conducted in helium. Comparisons of the fatigue and subcritical growth behavior in air between Hastelloy X and a number of other structural alloys are given.

  8. Application of Hastelloy X in gas-cooled reactor systems

    Hastelloy X, an Ni--Cr--Fe--Mo alloy, may be an important structural alloy for components of gas-cooled reactor systems. Expected applications of this alloy in the High-Temperature Gas-Cooled Reactor (HTGR) are discussed, and the development of interim mechanical properties and supporting data are reported. Properties of concern include tensile, creep, creep-rupture, fatigue, creep-fatigue interaction, subcritical crack growth, thermal stability, and the influence of helium environments with controlled amounts of impurities on these properties. In order to develop these properties in helium environments that are expected to be prototypic of HTGR operating conditions, it was necessary to construct special environmental test systems. Details of construction and operating parameters are described. Interim results from tests designed to determine the above properties are presented. To date a fairly extensive amount of information has been generated on this material at Oak Ridge National Laboratory and elsewhere concerning behavior in air, which is reviewed. However, only limited data are available from tests conducted in helium. Comparisons of the fatigue and subcritical growth behavior in air between Hastelloy X and a number of other structural alloys are given

  9. A Study on the High Temperature Oxidation Behavior of Hastelloy X and Inconel 713C

    In order to preserve surface stability and mechanical properties of the substrate materials, coatings are applied to the alloy surfaces for the high temperature applications. Even with the application of coating, the substrate materials must also have its own resistance to the high temperature oxidation because the substrate may be catastrophically degraded when coatings are failed. In this research, Ni-base superalloys, IN 713C and Hastelloy X for the substrate materials of coatings, were examined by the isothermal and cyclic oxidation experiments. In the isothermal oxidation experiments, the dominant protective oxide scale of Hastelloy X was Cr2O3 and that of IN 713C was the Al-rich oxide scale. Both alloys formed protective oxide scales, and showed good isothermal oxidation resistance but IN 713C showed better oxidation resistance than Hastelloy X owing to the formation of Al-rich oxide scales. Also for cyclic oxidation experiments, due to the favorable adhesion between the substrate and oxide scales, IN 713C having thin Al-rich oxide scales showed better oxidation resistance than Hastelloy X throughout the temperature ranges tested. Comparing these two alloys IN 713C had better oxidation resistance but both alloys showed good oxidation resistance up to 1000 .deg. C

  10. AC losses in filamentary YBCO/hastelloy

    Full text: The AC hysteresis loss of a long YBCO thin-film superconducting strip in a perpendicular AC magnetic field can be reduced by subdividing the film into narrow parallel strips (filaments). The hysteresis loss depends on the film critical current density Jc, the film thickness d, the filament width 2a and the lateral spacing L between filaments as well as on the AC magnetic field amplitude Hm. In addition, if the film is deposited onto a YSZ/hastelloy substrate to form a flexible tape, eddy current loss occurs in the hastelloy metal. The eddy current loss depends on the resistivity p of the hastelloy, the width 2w and thickness dm of the hastelloy substrate as well as on the frequency f and amplitude Hm. We have calculated the hysteresis and eddy current losses as a function of Jc, d, 2a, L, p, w, dm, f, and Hm to find optimal design parameters for a YBCO/hastelloy tape. As the AC loss is related to the loss component X'' of the AC susceptibility, we have measured X'' at different frequencies f and amplitudes Hm for several filamentary designs of YBCO/hastelloy tapes and compared our experimental results with our model calculations

  11. Heat-resistant fungi in the soil.

    Jesenská, Z; Piecková, E; Bernát, D

    1992-07-01

    The occurrence of heat-resistant fungi has been demonstrated in samples of soil from the Slovak Republic. The heat-resistant species isolated were Byssochlamys nivea, Dichotomomyces cejpii, Eupenicillium baarnense, Neosartorya fischeri, Talaromyces avellaneus, Tal. bacillisporus, Tal. emersonii, Tal. flavus, Tal. trachyspermus, Tal. wortmanii, Botryotrichum piluliferum, Gilmaniella humicola and Nodulisporium sp. Some of them were isolated for the first time from Czechoslovakian soil. For the various soil samples examined, the occurrence of heat-resistant fungi varied qualitatively and quantitatively. Further research is needed to identify conditions affecting the occurrence of heat-resistant fungi in soil. PMID:1445767

  12. Creep properties and simulation of weld repaired low alloy heat resistant CrMo and Mo steels at 540 deg C. Sub project 1 - Ex-serviced parent metal and virgin weld metals

    Rui Wu; Storesund, Jan; Borggreen, Kjeld; Weilin Zang

    2006-10-15

    Many existing power generating and process plants, where low alloy heat resistant CrMo(V) steels are extensively used for critical components, have exceeded their design lifetime of usually 100,000 hours. Assessment of residual lifetime and extension of economic life by weld repair have become increasingly important and attractive. This project aims at i) performing weld repair and determining the degree of mismatching, ii) evaluating the creep properties of weld repairs, iii) analysing creep behaviour of weld repair and providing necessary data for further reliable simulations of weld repair creep behaviour in long term service, and iv), simulating and assessing lifetime and creep damage evolution of weld repair. Weld repair using 10 CrMo 9 10, 13 CrMo 4 4 and 15 Mo 3 consumables has been carried out in a service-exposed 10 CrMo 9 10 pipe. Creep specimens have been extracted from the service-exposed 10 CrMo 9 10 parent metal (PM), from the virgin 10 CrMo 9 10 weld metal (WM), from the virgin 13 CrMo 4 4 WM as well as from the virgin 15 Mo 3 WM. Iso-thermal uniaxial creep tests have been performed at 540 deg C in air. Pre- and post-metallography are carried out on the selected samples. FEM simulations using obtained creep data are executed. Pre-test metallography shows normal and acceptable weld repairs at given welding conditions. Creep tests demonstrate that the virgin 10 CrMo 9 10, 13 CrMo 4 4 and 15 Mo 3 WMs have apparently longer creep lifetime than the service-exposed CrMo 9 10 PM at higher stresses than 110 MPa. Among the weld metals, the longest creep lifetime is found in 10 CrMo 9 10. Higher creep strength and lower creep strain rate in the weld metals indicate an overmatch weld. At 95 MPa, however, lifetime of 13 CrMo 4 4 WM is surprisingly short (factors which may shorten lifetime are discussed and one more test will start to verify creep strength at low stress) and tests are still running for other two weld metals. More results regarding low stress creep behaviour will therefore be available at phase 2 of the project. Together with the results of creep tests on the crosswelds and simulations, concrete conclusions and recommendations will be also given at phase 2 of the project. Transgranular failure is predominant, independent of stresses and materials. Pores/cavities are only found adjacent to the fracture. FEM simulations using obtained creep data predict fracture in corresponding weld metal. Extrapolation of the creep results to service stress, i.e. 35 MPa, results in undermatched welds for repairs with 13 CrMo 4 4 and 15 Mo 3 weld metals. Norton's law, Monkman-Grant relation and {phi}- and {omega}-models (strain-strain rate) are valid for both parent and weld metals. These models can be utilised for lifetime assessment and reproduction of creep curves. Using {phi}- and {omega}-models, creep curves have been successfully reproduced and the reproduced creep curves are comparative with the experiments. Creep tests on the weld metals at low stress as well as on cross-weld specimens at phase 2 of the project are expected to provide more results, comprehensive understanding of creep behaviour in weld repair as a whole and reliable simulations.

  13. Heat resistant fungi isolated from soil.

    Piecková, E; Bernát, D; Jesenská, Z

    1994-06-01

    The Thermal death time values (TDT) were estimated for Dichotomomyces cejpii, Gilmaniella humicola, Talaromyces avellaneus and Talaromyces bacillisporus isolated from soil. TDT values were compared with the TDT values of the known heat-resistant species, Byssochlamys nivea, Neosartorya fischeri and Talaromyces flavus. All species studied showed considerable heat resistance. The most resistant species Talaromyces avellaneus (172 cfu, initial concentration) of the isolates with unknown heat resistance withstood 90 degrees C for 10 min. Byssochlamys nivea appeared to be the most sensitive species under our experimental conditions. PMID:7986681

  14. Weldability of the superalloys Haynes 188 and Hastelloy X by Nd:YAG

    Graneix Jérémie; Beguin Jean-Denis; Pardheillan François; Alexis Joël; Masri Talal

    2014-01-01

    The requirements for welded aircraft parts have become increasingly severe, especially in terms of the reproducibility of the geometry and metallurgical grade of the weld bead. Laser welding is a viable method of assembly to meet these new demands, because of automation, to replace the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X and Haynes 188 alloys by the butt welding process with a Nd:YAG laser. To identify the influential parameters...

  15. Preliminary Assessment of Oxidation Pretreated Hastelloy as Hydrocarbon Steam Reforming Catalyst

    de la Rama, S. R.; Kawai, S; Yamada, H.; Tagawa, T.

    2014-01-01

    The potential of oxidation pretreated Hastelloy tube as a hydrocarbon steam reforming catalyst was assessed using tetradecane, toluene, and naphthalene as model compounds. Surface characterization showed that Fe2O3, Cr2O3, MoO3, and NiO were formed on the surface of the alloy after oxidation at 1000C for 2 hours. Catalytic evaluation showed good activity and stability with tetradecane while lower activity with increased rate of carbon formation was observed with naphthalene.

  16. Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts

    David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

    2005-01-30

    This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

  17. Air oxidation and seawater corrosion of Hastelloy S and Hastelloy C-4

    A program is currently under way at the Pacific Northwest Laboratory (PNL) to develop the data and technology needed to permit the licensing of 90SrF2 as a radioisotope heat source fuel for terrestrial applications. The WESF 90SrF2 storage capsule consists of a Hastelloy C-276 inner capsule (2 in. I.D. x 19 in. long) and a 316L stainless steel outer capsule (2-3/8 in. I.D. x 20 in. long). Preliminary experimental tests and theoretical calculations show that the WESF storage capsule is incapable of meeting current licensing requirements for heat sources that are to be used for terrestrial applications. Therefore, the DOE decision was to develop a new heat source design that would retain the existing WESF Hastelloy C-276 inner capsule and replace the current WESF outer capsule with a new outer capsule capable of meeting current licensing requirements. Based on a number of factors, Hastelloy S was selected as the outer capsule material. Hastelloy C-4 was selected as a backup material in case the Hastelloy S had to be rejected for any reason. This report summarizes the results of studies carried out to determine the effects of both air oxidation at heat source operating temperatures and seawater corrosion on the tensile properties of the outer capsule materials

  18. Air oxidation and seawater corrosion of Hastelloy S and Hastelloy C-4

    Fullam, H.T.

    1980-03-01

    A program is currently under way at the Pacific Northwest Laboratory (PNL) to develop the data and technology needed to permit the licensing of /sup 90/SrF/sub 2/ as a radioisotope heat source fuel for terrestrial applications. The WESF /sup 90/SrF/sub 2/ storage capsule consists of a Hastelloy C-276 inner capsule (2 in. I.D. x 19 in. long) and a 316L stainless steel outer capsule (2-3/8 in. I.D. x 20 in. long). Preliminary experimental tests and theoretical calculations show that the WESF storage capsule is incapable of meeting current licensing requirements for heat sources that are to be used for terrestrial applications. Therefore, the DOE decision was to develop a new heat source design that would retain the existing WESF Hastelloy C-276 inner capsule and replace the current WESF outer capsule with a new outer capsule capable of meeting current licensing requirements. Based on a number of factors, Hastelloy S was selected as the outer capsule material. Hastelloy C-4 was selected as a backup material in case the Hastelloy S had to be rejected for any reason. This report summarizes the results of studies carried out to determine the effects of both air oxidation at heat source operating temperatures and seawater corrosion on the tensile properties of the outer capsule materials.

  19. Plasma treatment of heat-resistant materials

    Vlasov, V. A.; Kosmachev, P. V.; Skripnikova, N. K.; Bezukhov, K. A.

    2015-11-01

    Refractory lining of thermal generating units is exposed to chemical, thermal, and mechanical attacks. The degree of fracture of heat-resistant materials depends on the chemical medium composition, the process temperature and the material porosity. As is known, a shortterm exposure of the surface to low-temperature plasma (LTP) makes possible to create specific coatings that can improve the properties of workpieces. The aim of this work is to produce the protective coating on heat-resistant chamotte products using the LTP technique. Experiments have shown that plasma treatment of chamotte products modifies the surface, and a glass-ceramic coating enriched in mullite is formed providing the improvement of heat resistance. For increasing heat resistance of chamotte refractories, pastes comprising mixtures of Bacor, alumina oxide, and chamot were applied to their surfaces in different ratios. It is proved that the appropriate coating cannot be created if only one of heat-resistant components is used. The required coatings that can be used and recommended for practical applications are obtained only with the introduction of powder chamot. The paste composition of 50% chamot, 25% Bacor, and 25% alumina oxide exposed to plasma treatment, has demonstrated the most uniform surface fusion.

  20. Creep properties of 20% cold worked hastelloy XR

    Creep properties of Hastelloy XR, in 20% cold worked or solution treated condition, were studied at 800, 900 and 1000degC. The results obtained are as follows: (1) At 800degC, creep rupture time of 20% cold worked Hastelloy XR is longer than that of solution treated one. However, the effect disappears above 900degC. At 1000degC, it becomes shorter than that of solution treated Hastelloy XR. (2) Rupture elongation and reduction of area of 20% cold worked Hastelloy XR are smaller than those of solution treated one. While these values of 20% cold worked Hastelloy XR are lowest at 900degC, they recover considerably at 1000degC. (3) Nonclassical creep curves which have the region with low creep rate at an early stage of creep were observed at high temperatures for Hastelloy XR, in 20% cold worked or solution treated condition. (4) Minimum creep rate, εm, of 20% cold worked Hastelloy XR is decreased by as much at a factor of 20 to 50 at 800 and 900degC. On the other hand, εm of 20% cold worked Hastelloy XR is increased by as much as a factor of 2 at 1000degC. (5) Although 20% cold work enhances creep resistance of Hastelloy XR at 800 and 900degC, the effect becomes detrimental at 1000degC where dynamic recrystallization occurs during creep. (author)

  1. Torsional creep characteristics of Hastelloy X

    Nonlinear analysis method can be applied for rationalized design of nuclear component at elevated temperature, verification of constitutive equation is required under the multi-axial cyclic loading. In our company, high-temperature tension-torsion testing machine has been developed to understand multi-axial material characteristics at elevated temperature and to verify nonlinear constitutive equation. In this paper, torsional creep characteristics of Hastelloy X at 900degC are reported and applicability of nonlinear analysis method to actual design is discussed. (author)

  2. Corrosion of Inconel-625, Hastelloy-X280 and Incoloy-800 in 550 - 750°C superheated steam. Influence of alloy heat treatment, surface treatment, steam temperature and steam velocity. Part I: Results up to 6000 hours exposure time. RCN Report

    Sheet samples of Inconel-625, Hastelloy-X280 and Incoloy-800 were tested, in the solution annealed and in the solution annealed + 20% cold worked + 800°C tempered condition, in steam with a velocity of 5 m/sec. at 550, 650 and 750°C and in steam with a volocity of 15 and 85 m/sec. at 550°C. At 550°C and 750°C the samples were tested in the heat treated, annealed or tempered and the heat treated + electropolished condition. At 650°C moreover as heat treated + ground and pickled samples were tested. Post-corrosion sample investigations involved measurement of the adherent oxide thickness, the total amount of corroded metal, the metal loss to system, and the metallographic and microprobe investigation of the adherent oxide film and adjacent diffusion disturbed alloy layer. The results obtained up to 6000 hours exposure time showed that the surface treatment has a decisive influence on the corrosion behaviour of all three alloys tested. The differences in the corrosion data for the two heat treatment conditions are small. The influence of the steam velocity, as tested at 550°C, on the initial corrosion rate was surprisingly high, while the long-term linear corrosion rates are only slightly influenced by the gas velocity. In general the linear corrosion rates were low, 1-5 mg/dm2 month, and not consistently affected by the test-temperature. The metal loss to system values were 2 <15 mg/dm2 in the low velocity steam at all three test temperatures and <30 mg/dm2 in the high velocity steam at 550°C. The metallographic and microprobe examinations revealed no remarkable results, as compared with the results of analogous tests reported in literature. (author)

  3. Application of newly developed heat resistant materials for USC boilers

    This paper describes the research on the development and improvement of new high strength heat resistant steels such as SUPER304H (18Cr-9Ni-3Cu-Nb-N), NF709 (20Cr-25Ni-1.5Mo-Nb-Ti-N) and HR3C (25Cr-20Ni-Nb-N) as boiler tube, and NF616 (9Cr-0.5Mo-1.8W-Nb-V) and HCM12A (11Cr-0.4Mo-2W-Nb-V-Cu) as thick section pipe. The latest manufacturing techniques applied for these steels are introduced. In addition the high temperature strength of Alloy617 (52Ni-22Cr-13Co-9Mo-Ti-Al) that is one of the candidate materials for the next generation 700 □ USC boilers is described. (orig.)

  4. Heat-resistant ferrochrome slag based concrete

    M.T. Zuginisov; M.M. Myrzahmetov; D.T. Sartayev; Ye.S. Orynbekov

    2014-01-01

    In the construction materials industry, expensive refractories (fire clay, silica, high- aluminous, etc.), are used as the main lining materials which despite their high fire resistance are inefficient for the use in thermal aggregates with an operation temperature up to 1300 °C. The purpose of the research was to develop heat-resistant concrete on the basis of sodium silicate binder and liquid glass with application of ferrochrome slag. Studies on the use of ferrochrome slag to obtain h...

  5. CORN CULTIVAR IDENTIFICATION THROUGH HEAT RESISTANT PROTEINS

    SOLANGE CARVALHO BARRIOS ROVERI JOSÉ

    2004-04-01

    Full Text Available Stable and polymorphic markers are required for the identification and registration of the cultivars. The purpose of this research was to evaluate the heat resistant proteins polymorphism and stability of seeds from corn lines harvested in different years and dried under natural and artificial conditions, in order to employ such proteins in the identification and registration of the cultivars. The seeds showed different physiological quality when evaluated by germination test and the heat resistant proteins were extracted from embryonic axis from seeds of each line, in Tris-HCl 0,05 M buffer. The eletrophoretic patterns of these proteins in SDS-PAGE showed stable bands for each genotype even for the lines with higher variation in the germination test. The most similar corn inbred lines were distinguished, at least by two bands, showing that these proteins were highly polymorphic. The stability and the high level of polymorphism of the heat resistant proteins, make them potential markers in corn cultivars registration and identification programs.

  6. Investigation of the creep behaviour of heat resistant gas turbine alloys. [Materials: Inconel 718, FSX 414, Udimet 500, IN-713C, IN-100, IN-738LC, IN-939, Nimonic 101

    Kloos, K.H.; Granacher, J.; Bartsch, H.

    1986-06-01

    The high temperature deformation behaviour of typical investment cast materials and wrought alloys is measured in tensile tests, continuous and interrupted creep tests and annealing tests. In a special evaluation method the strain values determined in the different tests are combined. Examples for characteristic creep values and for creep equations are given.

  7. Effect of Mn on oxidation resistance of hastelloy X in simulated VHTR helium environment

    Oxidation behavior of several heats of Ni-base alloy Hastelloy X with different Mn contents was studied. The exposure tests were made with impure helium at 10000C simulating a Very High Temperature Reactor (VHTR) coolant. Characterized by the selective oxidation of some limited number of chemically active minor elements in the alloy in the low potential oxidizing environment, the oxidation resistance was found to be controlled by factors unique to this system. Manganese in particular was shown to be a special element that formed a spinel oxide with Cr in the environment; its effect on kinetics of the surface reactions was studied. The addition of Mn up to 1.3% improve oxidation resistance of Hastelloy X, possibly due to the formation of the outer MnCr2O4 spinel oxide layer outside the inner Cr2O3 oxide layer. Based on the observed increase in the MnCr2O4/Cr2O3 thickness ratio with Mn content, a proposal was made in protecting the alloy by the optimum Mn addition. (author)

  8. Thermophysical Properties of Heat Resistant Shielding Material

    This project was aimed at determining thermal conductivity, specific heat and thermal expansion of a heat resistant shielding material for neutron absorption applications. These data are critical in predicting the structural integrity of the shielding under thermal cycling and mechanical load. The measurements of thermal conductivity and specific heat were conducted in air at five different temperatures (-31 F, 73.4 F, 140 F, 212 F and 302 F). The transient plane source (TPS) method was used in the tests. Thermal expansion tests were conducted using push rod dilatometry over the continuous range from -40 F (-40 C) to 302 F (150 C)

  9. Electrochemical impedance spectrometry using 316L steel, hastelloy, maraging, Inconel 600, Elgiloy, carbon steel, TiN and NiCr. Simulation in tritiated water. 2 volumes

    Polarization and electrochemical impedance spectrometry curves are presented and discussed. These curves make it possible to ascertain the corrosion domains and to compare the slow and fast kinetics (voltammetry) of different stainless steel alloys. These corrosion kinetics, the actual or simulated tritiated water redox potentials, and the corrosion potentials provide a classification of the steels studied here: 316L, Hastelloy, Maraging, Inconel 600, Elgiloy, carbon steel and TiN and NiCr deposits. From the results it can be concluded that Hastelloy and Elgiloy have the best corrosion resistance. (author). 49 refs., 695 figs., tabs

  10. Heat-resistant protective and special coatings

    The paper reviews heat-resistant protective and special coatings of practical uses. To protect the structures against chemical destruction in hot acid-alkaline solutions, chemically resistant coatings are developed. The best protective effect in such media is provided by silicate enamels. New potentialities in the field of enamel coatings were revealed recently in connection with the creation of glass-crystalline (sital) enamels. A separate type of metal protection is represented by glass lining. The heat-resistant coatings include metal-like and cermet coatings. Wear-resistant coatings protect machine parts against mechanical wear under various types of friction. Heat-insulating coatings protect structures against superheating and softening at elevated temperatures. The formation of weld-up on metal cast surfaces could be prevented by means of anti-weld-up coatings. Anti-tarring coatings are known which are capable of preventing tarring. Various types of sticking are eliminated by means of anti-adhesive coatings. Electrical insulation coatings occupy an important place in the modern engineering. The electroconducting coatings are of the opposite purpose. The investigations being carried out are based on the general scientific principles

  11. Thermal adhesion of heat-resistant materials in high temperature gas-cooled reactors and methods to prevent it

    High temperature gas-cooled reactors (HTGRs) have many high-temperature sliding or contacting parts. Generally these can be divided into contact between metal parts in each other and contact between metal and graphite. The authors set out to clarify adhesion behavior between metal and metal, and to acquire techniques that effectively prevent adherence of various heat-resistant materials in high temperature helium gas environments. Hastelloy X, Incoloy 800, Inconel 625 and Inconel 601 were investigated in the experiments. The obtained result shows that the ZrO2 coating using a plasma spray process is the most effective method to prevent adhesion of these materials at working temperatures in excess of 8000C (1,4700F). Subsequently the experimental results were actually applied in the design and fabrication of the Oarai Gas Loop 1 (OGL-1) and the High Temperature Gas Loop (HTGL) in the Japan Atomic Energy Research Institute. (author)

  12. Compatibility of aluminide-coated Hastelloy X and Inconel 617 in a simulated gas-cooled reactor environment

    Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 850 and 9500C for 3000 h. Optical microscopy, scanning electron microscopy (SEM), electron microprobe profiles and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon phase (Ni3Al). This diffusion was the primary cause of porosity formation at the aluminide-alloy interface. Aluminide coatings with chromium (HI-15) showed the lowest coating-substrate interface porosity and intermetallic phase growth. The presence of excess chromium in the HI-15-aluminide-coated Hastelloy X sample is believed to have compensated partially for the nickel loss by its diffusion into the nickel-depleted coating-substrate transition zone. None of the other coating additions had an obvious effect on the overall behavior of aluminide-coated Hastelloy X or Inconel 617 in the impure helium environment. The exterior of the aluminide coatings was not visually affected by the impure helium. Carbide precipitation below the coating-substrate interface, resulting from carbon ingress from the helium environment, was observed in uncoated control samples. Carburization of aluminide-coated substrates was less extensive than that of uncoated materials and was related to the degree of porosity at the coating-alloy interface. (Auth.)

  13. Heat resistant concrete (Rhine sand concrete)

    The heat resistant concrete has a fresh concrete density of at least 2300 kg/m3, a great strength in the temperature range 200 to 3000C, and is intended for prestressed concrete reactor pressure vessels, for nuclear reactors, particularly high temperature reactors. It consists of a quantity of hydraulic cement with water, concrete additives of quartz and flyash as additives and to delay solidification and concrete liquifier as additive. For a water cement value of 0.40, the quantity has a fine grain content of 29% of the additive. The flyash and finely divided quartz grain content causes a rise in strength in hydrothermal conditions, which counteracts the loss of strength due to temperature effects. (orig./PW)

  14. Optimization in Si content of hastelloy XR for oxidation resistance and oxide film adherence during oxidation in VHTR helium

    Oxidation behavior of several heats of modified Hastelloy alloy X, named Hastelloy XR, with different Si contents was examined in isothermal, thermal cycling exposure tests. The test environment was flowing helium at 10000C containing controlled amounts of impurities simulating the Very High Temperature gas-cooled Reactor (VHTR) coolant. Tests were made to determine an optimization rang of Si content for obtaining higher resistance to the oxidation and less oxide spallation in the service environment. Up to 1% content, increase of the Si caused decrease of the oxidation rate, while the oxide spallation in thermal cycling was a minimum in the range of about 0.2 to 0.4% Si. These two could be explained in formation and morphology of the SiO2 phase in the oxide and metal interface by metallographic observation and analysis. (author)

  15. Effect of cold work on creep properties of Hastelloy XR

    Creep tests of Hastelloy XR, in 10%, 20% cold worked or solution treated condition, were made at 800 at 1000degC for times up to about 2000 ks in order to investigate the effect of cold work on creep properties. The results obtained are as follows: (1) Below 950degC, creep rupture strength of 10% cold worked Hastelloy XR is beyond the value of solution treated one within this experimental condition. 950degC and cold work of 10% are the highest values experienced in an intermediate heat exchanger of the High Temperature Engineering Test Reactor(HTTR) under normal condition, respectively. (2) At 800 and 850degC, creep rupture time of 20% cold worked Hastelloy XR is longer than that of solution treated one. However, the effect disappears above 900degC. At 950 and 1000degC, it becomes shorter than that of solution treated Hastelloy XR. (3) Rupture elongation and reduction of area of cold worked Hastelloy XR are smaller than those of solution treated one. While these values of 10% or 20% cold worked material are lowest at 900degC, they recover considerably at 1000degC. (4) Minimum creep rate, εm, of 10% or 20% cold worked Hastelloy XR is decreased by as much as a factor of 20 to 50 at 800 to 900degC. On the other hand, εm of 10% or 20% cold worked material is increased at 1000degC. (5) From the results of microstructure observation of ruptured specimens, decrease in creep rupture strength of cold worked Hastelloy XR is interpreted in terms of extensive recrystallization which occurs during creep at 1000degC. (author)

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

    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.

  17. Efficiency of out-of-furnace modification of heat resistant chromium-nickel steel with titanium and boron

    The investigation results on out-of-furnace modifying a heat resisting steel with Al, Ti, B, Ce and Ca are presented. the influence of above-mentioned alloying elements on room and high temperature mechanical properties is shown. A modifying complex of titanium and boron has been selected, and the needed quantity of these elements ensuring an increase of mechanical and service properties of heat resistant articles has been determined. Based on the results obtained the chemical composition of steel 35Kh22N10STRL has been corrected. The technology has been put into practice

  18. A new ferritic heat resisting steel

    A new ferritic heat resisting steel, 9Cr-2Mo-Nb-V steel (NSCR9), with almost the same strength as that of austenitic stainless steel 304 at temperatures of about 6000C has been developed in response to strong demands by boiler fabricators. Advantages of this new type steel compared with conventional 9Cr-1Mo steel are: 1) less carbon content which improves weldability and formability; 2) higher creep rupture strength which is caused by precipitation of fine carbides and carbonitrides. The fine precipitates are obtained by addition of a small amount of Nb and V corresponding to the carbon content. This new steel exhibits at least twice as much strength in the temperature range of 5500C to 6000C as compared with 2 1/4Cr-1Mo steel and with conventional 9Cr-1Mo steel, and is superior to HT-9 by approximately 30%. Its allowable stress is the same as that of TP304H at 5850C. This steel also shows higher resistance to embrittlement during service. The necessary welding electrodes with similar composition have been developed for gas tungsten arc and for submerged manual arc welding. Welded joint characteristics are satisfactory. As ferritic steels in general have higher resistance to swelling by neutron irradiation, this new type steel can also be useful for nuclear service in FBR and fusion reactor

  19. Hemispherical total emissivity of Hastelloy N with different surface conditions

    The hemispherical total emissivity of Hastelloy N (a candidate structural material for Next Generation Nuclear Plants (NGNPs), particularly for the molten fluoride cooled reactors) was measured using an experimental set-up that was constructed in accordance with the standard ASTM C835-06. The material surface conditions included: (i) ‘as received’ (original) sample from the supplier; (ii) samples with increased surface roughness through sand blasting; (iii) oxidized surface, and (iv) samples coated with graphite powder. The emissivity of the as received samples varied from around 0.22 to 0.28 in the temperature range of 473 K to 1498 K. The emissivity increased when the roughness of the surface increased compared to an as received sample. When Hastelloy N was oxidized in air at 1153 K or coated with graphite powder, its emissivity increased substantially. The sample sand blasted with 60 grit beads and sprinkled with graphite powder showed an increase of emissivity from 0.2 to 0.60 at 473 K and from 0.25 to 0.67 at 1473 K. The oxidized surface showed a similar behavior: an increase in emissivity compared to an unoxidized sample. This increase in emissivity has strong favorable safety implications in terms of decay heat removal in post-accident environments. The data were compared with another Hastelloy family member, Hastelloy X.

  20. Machinability of hastelloy C-276 using Hot-pressed sintered Ti(C7N3)-based cermet cutting tools

    Xu, Kaitao; Zou, Bin; Huang, Chuanzhen; Yao, Yang; Zhou, Huijun; Liu, Zhanqiang

    2015-05-01

    C-276 nickel-based alloy is a difficult-to-cut material. In high-speed machining of Hastelloy C-276, notching is a prominent failure mode due to high mechanical properties of work piece, which results in the short tool life and low productivity. In this paper, a newly developed Ti(C7N3)-based cermet insert manufactured by a hot-pressing method is used to machine the C-276 nickel-based alloy, and its cutting performances are studied. Based on orthogonal experiment method, the influence of cutting parameters on tool life, material removal rates and surface roughness are investigated. Experimental research results indicate that the optimal cutting condition is a cutting speed of 50 m/min, depth of cut of 0.4 mm and feed rate of 0.15 mm/r if the tool life and material removal rates are considered comprehensively. In this case, the tool life is 32 min and material removal rates are 3000 mm3/min, which is appropriate to the rough machining. If the tool life and surface roughness are considered, the better cutting condition is a cutting speed of 75 m/min, depth of cut of 0.6 mm and feed rate of 0.1 mm/r. In this case, the surface roughness is 0.59μm. Notch wear, flank wear, chipping at the tool nose, built-up edge(BUE) and micro-cracks are found when Ti(C7N3)-based cermet insert turned Hastelloy C-276. Oxidation, adhesive, abrasive and diffusion are the wear mechanisms, which can be investigated by the observations of scanning electron microscope and energy-dispersive spectroscopy. This research will help to guide studies on the evaluation of machining parameters to further advance the productivity of nickel based alloy Hastelloy C-276 machining.

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

    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.)

  2. Compatibility of aluminide-coated Hastelloy x and Inconel 617 in a simulated gas-cooled reactor environment

    Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 8500 and 9500C for 3000 h. Optical and scanning electron (SEM) microscopy, electron microprobe profiles, and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon-phase (Ni3Al). This diffusion was the primary cause of porosity formation at the aluminide/alloy interface

  3. Development of super heat-resistant turbocharger

    Yoritaka, Masashi; Yamamoto, Yukio; Hasegawa, Yasuaki; Hokari, Tomio

    1987-09-01

    In recent years, the exhaust gas temperature has increased due to high power of motorvehicles, causing such problems as breakage of turbine blades resulting from the shortage of high temperature creep strength, and as for turbine casings, as thermal deformation, cracks and generation of oxide films resulting from the shortages of high temperature creep strength and acid resistance. For these problems, it was tried to adopt Ni-base super-alloy, MAR-M247 for turbine blades and Co-base super-alloy FSX414 for turbine casings. During the above process, the knowledge which is stated hereunder was obtained. Breakage life of turbine blade is related closely to the high temperature stability of ..cap alpha..' phase of the super-alloy concerned. As for the mechanism of breakage, it starts from the elongation of turbine blade, followed by the creation of creepvoid inside which develops to cracks on the outer surface before reaching the breakage stage. Fracturing starts from the inside cristal grains. Stronger blades are made as the unidirectional solidified organization without lateral cristal grains is formed as perfectly as possible. Consequently, it is necessary to control positively the organization formation in order to achieve this unidirectional solidified organization. (16 figs, 3 tabs, 7 refs)

  4. An investigation into crystalline phases and nano structural and mechanical properties of HH heat resistant stainless steels

    M Hosseini; Bahari, A; F Ahmadian

    2015-01-01

    In the present work, the effects of different casting parameters including pouring temperature and cooling rate on stainless steel structures and mechanical properties of heat resistant alloy (HH) were studied. Mo nanoparticles were synthesized through sol-gel method and were coated on the stainless steel device using spin-coating method. The effect of coating layer on the device was studied by using XRD (X-Ray Diffraction) and FT-IR (Fourier Transform Infra red ) and SEM (Scanning Electron M...

  5. Temperature dependence of creep properties of cold-worked Hastelloy XR

    The creep properties of Hastelloy XR, in a solution treated, 10% or 20% cold-worked condition, were investigated at temperatures from 800 to 1,000degC for the duration of creep tests up to about 2,500 ks. At 800 and 850degC, the steady-state creep rate and rupture ductility decreased and the rupture life increased after cold work of 10% or 20%. Although the rupture life of the 10% cold-worked alloy was longer at 900degC than that of the solution treated one, the rupture lives of the 10% cold-worked and solution treated alloys were almost equal at 950degC, which is the highest helium temperature in an intermediate heat exchanger of the High Temperature Engineering Test Reactor (HTTR). The beneficial effect of 10% cold work on the rupture life and the steady-state creep rate disappeared at 1,000degC. The beneficial effect of 20% cold work disappeared at 950degC because significant dynamic recrystallization occurred during creep. While rupture ductility of this alloy decreased after cold work of 10% or 20%, it recovered to a considerable extend at 1,000degC. It is emphasized that these cold work effects should be taken into consideration in design, operation and residual life estimation of high temperature components of the HTTR. (author)

  6. Refractory metal based alloys

    Given are the basic data, regarding the properties of the tungsten, molybdenum-, niobium- and tantalum-based alloys and the basic trends for the Use of these alloys. Shown are the possibilities to enhance the heat-resistant and strength properties of the metals throught alloying and to use the protective coatings

  7. Study on the heat-resistant EB curing composites

    There are many advantages in the EB-curing process of composites. Heat-resistant EB-curing composites could substitute for polyimide composites used in aeronautical engine. The effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical thermal analysis (DMTA). The experiment result shows that the mechanical property of the composites cured by EB could meet the needs of the aeronautical engine in 250degC. (author)

  8. Study on the heat-resistant EB curing composites

    Bao Jianwen; Li Yang [Institute of Aeronautical Materials, Beijing (China); Li Fengmei [Institute of Low Energy Nuclear Physics, Beijing Normal Univ., Beijing (China)

    2000-03-01

    There are many advantages in the EB-curing process of composites. Heat-resistant EB-curing composites could substitute for polyimide composites used in aeronautical engine. The effects of catalyst and dose on the cured resin were investigated. The heat-resistance of the resin cured by EB was evaluated by dynamic mechanical thermal analysis (DMTA). The experiment result shows that the mechanical property of the composites cured by EB could meet the needs of the aeronautical engine in 250degC. (author)

  9. Heat resistance insulation for NPP pipelines and components

    To insulate hot surfaces of NPP process equipment and pipes it is suggested to use heat resistant insulation of foam aminoimides (FAI). Relative toxicity of aceton and acetaldehyd evolved from FAI in the process of thermal and thermal-oxidative break-down was determined. FAI can be used at 200 deg C

  10. Determination of preheating temperature for welding of heat resisting steels

    An effect of thermal ageing and blue brittleness on the properties of a weld metal and a heat affected zone has been investigated on 12Kh1MF, 15Kh2MFA and other steels. It is shown that during welding of heat-resistant steels the preheating temperature should not exceed 130-180 deg C

  11. Feasibility of EB Welded Hastelloy X and Combination of Refractory Metals

    Martinez, Diana A.

    2004-01-01

    As NASA continues to expand its horizon, exploration and discovery creates the need of advancement in technology. The Jupiter Icy Moon Orbiter's (JIMO) mission to explore and document the outer surfaces, rate the possibility of holding potential life forms, etc. within the three moons (Callisto, Ganymede, and Europa) proves to be challenging. The orbiter itself consists of many sections including: the nuclear reactor and the power conversion system, the radiator panels, and the thrusters and antenna. The nuclear reactor serves as a power source, and if successfully developed, can operate for extended periods. During the duration of my tenure at NASA Glenn Research Center's (NASA GRC) Advanced Metallics Branch, I was assigned to assist Frank J. Ritzert on analyzing the feasibility of the Electron Beam Welded Hastelloy X (HX), a nickel-based superalloy, to Niobium- 1 %Zirconium (Nb-1 Zr) and other refractory metals/alloys including Tantalum, Molybdenum, Tungsten, and Rhenium alloys. This welding technique is going to be used for the nuclear reactor within JIMO.

  12. Study on tritium hydrogen permeation in the HTTR hydrogen production system. 1. Hydrogen permeability of Hastelloy XR (contract research)

    The High-Temperature Engineering Test Reactor (HTTR) is under construction at Japan Atomic Energy Research Institute (JAERI), and the first criticality is scheduled in the second half of 1998. After the reactor performance and safety demonstration test will be performed for several years, a hydrogen production system by steam reforming of natural gas will be coupled with the HTTR. Prior to coupling of the steam reforming system with the HTTR, an out-of-pile test and essential tests are planned to confirm the safety, controllability and performance of this system under simulated operational conditions. In order to obtain detailed data for a safety review and development of analytical codes, a hydrogen permeation test is carried out with a small-scale apparatus as one of the essential tests. The objective of this study is to evaluate the effectiveness of counter diffusion of hydrogen isotope and oxygen or coating film on the tube surface to reduce the amount of permeated hydrogen. The hydrogen and deuterium permeability of Hastelloy XR and other high-temperature alloys, which will be applied as the tube of an intermediate heat exchanger (IHX) and of a steam reformer (SR), can be obtained from the present test. This paper describes an outline of the hydrogen permeation test apparatus and the hydrogen permeability of Hastelloy XR under the high-temperature conditions ranging from 600degC to 850degC. (author)

  13. Investigations on the microstructure and mechanical properties of multi-pass pulsed current gas tungsten arc weldments of Monel 400 and Hastelloy C276

    Highlights: • For the first time study on the dissimilar weldments of Monel 400 and Hastelloy C276. • Pensive structure – property relationships of these weldments. • Improved micro-structural features. • Better ductility of the weldments through bend test results. - Abstract: This research article reported the weldability, microstructure and mechanical properties of the dissimilar combinations of nickel alloys such as Monel 400 and Hastelloy C276. Multi-pass pulsed current gas tungsten arc (PCGTA) welding was employed for joining these dissimilar metals using ERNiCrMo-3 filler. Interface microstructures showed the absence of unmixed zone at the HAZ of both the sides. It was evident from the studies that all the tensile failures occurred at Monel 400 side. The average impact toughness portrayed by these dissimilar weldments was found to be 41 J. Bend test results showed that these dissimilar combinations offer augmented ductility. The outcomes of the study substantiated the use of current pulsing for the successful joints of Monel 400 and Hastelloy C276 by correlating the mechanical and metallurgical properties

  14. High temperature strength of hastelloy x welded joints

    In the design of high temperature structures such as ASME Code N-47, the high temperature strength characteristics of welded joints become the problem. Also, the design of the welded parts in high temperature structures in the present state is according to the standard in which the bimetallic behavior of welded parts is not considered, accordingly, it is much problematic. In this paper, the high temperature strength characteristics of Hastelloy X welded joints are described, and the problems in the present design are pointed out, moreover, some comment is given to the evaluation of high temperature strength for the future. In the ASME Code, Case N-47, the strength of welded joints is required to be the same as that of parent metals. Therefore, the data on the high temperature strength of welded joints must be collected. The results of tensile test at room temperature, 700, 800, 900 and 1000 deg C on the parent metal and EB and TIG welded joints of Hastelloy X are shown. Also, the characteristics of mono-axial creep rupture, internal pressure creep rupture, and high temperature, low cycle fatigue are reported. The lowering of strength in the tension, creep and fatigue of welded joints must be examined and evaluated in view of the combined behavior of parent metals and weld metals. (Kako, I.)

  15. Heat resistant driving coil and control rod drive mechanism

    Ceramic materials are used for each part of driving coils and used as the driving coils for a driving shaft. That is, a cylindrical bobbin having outwardly protruding flanges on the entire circumference at the upper and the lower portions is made of stainless steels. Ceramics sheets are appended as necessary to the outer circumferential surface of the bobbin. Then, ceramic electric wires are wound around the outer circumference of the bobbin by a required number of turns to constitute coils. The electric wire is prepared by coating the conductor of nickel-plated copper with ceramic coating material, disposing an insulation material to the outer circumference thereof the further coating the outside with ceramic coating material. This can improve the heat resistance and, since the control rod drives using such heat resistant driving coils can operate at a high temperature. It requires no cooling device and can simplify the reactor and its peripheral structures. (T.M.)

  16. Leather Coated with Mixtures of Humectant and Antioxidants to Improve UV and Heat Resistance

    Ultraviolet (UV) and heat resistance are very important qualities for leather products. We recently developed an environmentally friendly finishing process for improving the UV- and heat resistance of automobile upholstery leather. We previously reported and demonstrated some promising results fro...

  17. Martensite-austenite transformation kinetics of high Cr ferritic heat-resistant steel

    Ma, Qiujia [Tianjin Univ. (China). State Key Lab. of Hydraulic Engineering Simulation and Safety; Tianjin Univ. (China). School of Materials Science and Engineering; Shao, Yi; Liu, Yongchang; Gao, Zhiming; Yu, Liming [Tianjin Univ. (China). State Key Lab. of Hydraulic Engineering Simulation and Safety

    2013-10-15

    The isochronal transformation behavior from martensite ({alpha}') to austenite ({gamma}) of modified high Cr ferritic heat-resistant steel was analyzed using the kinetic information extracted from differential thermal analysis results. The thus obtained {alpha}' {yields} {gamma} transformation kinetic process has been described by a JMAK-like model including three overlapping processes: site saturation nucleation, diffusion-controlled growth, and impingement correction for random distribution of nuclei. It is found that both the diffusion of alloying components and the inhibition of carbide precipitates strongly affect the {alpha}' {yields} {gamma} transformation kinetic processes. The {alpha}' {yields} {gamma} transformation (at relatively low heating rates) is of diffusion-controlled nature, and the obstruction of carbides during the migration of the {alpha}'/{gamma} interface leads to a decrease in the pre-exponential factor of diffusion coefficient. (orig.)

  18. Martensite-austenite transformation kinetics of high Cr ferritic heat-resistant steel

    The isochronal transformation behavior from martensite (α') to austenite (γ) of modified high Cr ferritic heat-resistant steel was analyzed using the kinetic information extracted from differential thermal analysis results. The thus obtained α' → γ transformation kinetic process has been described by a JMAK-like model including three overlapping processes: site saturation nucleation, diffusion-controlled growth, and impingement correction for random distribution of nuclei. It is found that both the diffusion of alloying components and the inhibition of carbide precipitates strongly affect the α' → γ transformation kinetic processes. The α' → γ transformation (at relatively low heating rates) is of diffusion-controlled nature, and the obstruction of carbides during the migration of the α'/γ interface leads to a decrease in the pre-exponential factor of diffusion coefficient. (orig.)

  19. Weldability of the superalloys Haynes 188 and Hastelloy X by Nd:YAG

    Graneix Jérémie

    2014-01-01

    Full Text Available The requirements for welded aircraft parts have become increasingly severe, especially in terms of the reproducibility of the geometry and metallurgical grade of the weld bead. Laser welding is a viable method of assembly to meet these new demands, because of automation, to replace the manual TIG welding process. The purpose of this study is to determine the weldability of Hastelloy X and Haynes 188 alloys by the butt welding process with a Nd:YAG laser. To identify the influential parameters of the welding process (laser power, feed rate, focal diameter and flow of gas while streamlining testing, an experimental design was established with the CORICO software using the graphic correlation method. The position of the focal point was fixed at 1/3 of the thickness of the sheet. The gas flow rate and the power of the beam have a major effect on the mechanical properties and geometry of the weld. The strength of the weld is comparable to that of the base metal. However, there is a significant decrease in the elongation at break of approximately 30%. The first observations of the cross section of the weld by scanning electron microscopy coupled with EBSD analysis show a molten zone presenting dendritic large grains compared to the equiaxed grains of the base metals without a heat affected zone.

  20. Material Data Representation of Hysteresis Loops for Hastelloy X Using Artificial Neural Networks

    Alam, Javed; Berke, Laszlo; Murthy, Pappu L. N.

    1993-01-01

    The artificial neural network (ANN) model proposed by Rumelhart, Hinton, and Williams is applied to develop a functional approximation of material data in the form of hysteresis loops from a nickel-base superalloy, Hastelloy X. Several different ANN configurations are used to model hysteresis loops at different cycles for this alloy. The ANN models were successful in reproducing the hysteresis loops used for its training. However, because of sharp bends at the two ends of hysteresis loops, a drift occurs at the corners of the loops where loading changes to unloading and vice versa (the sharp bends occurred when the stress-strain curves were reproduced by adding stress increments to the preceding values of the stresses). Therefore, it is possible only to reproduce half of the loading path. The generalization capability of the network was tested by using additional data for two other hysteresis loops at different cycles. The results were in good agreement. Also, the use of ANN led to a data compression ratio of approximately 22:1.

  1. Study on the creep constitutive equation of Hastelloy X, (1)

    A creep constitutive equation of Hastelloy X was obtained from available experimental data. A sensitivity analysis of this creep constitutive equation was carried out. As the result, the following were revealed: (i) Variations in creep behavior with creep constitutive equation are not small. (ii) In a simpler stress change pattern, variations in creep behavior are similar to those in the corresponding fundamental creep characteristics (creep strain curve, stress relaxation curve, etc.). (iii) Cumulative creep damage estimated in accordance with ASME Boiler and Pressure Vessel Code Case N-47 from a stress history predicted by ''the standard creep constitutive equation'' which predicts the average behavior of creep strain curve data is not thought to be on the safe side on account of uncertainties in creep damage caused by variations in creep strain curve. (author)

  2. AC magnetization losses in striated YBCO-123/Hastelloy coated conductors

    In this work we present experimental results of reductions in AC magnetization losses due to a striation process in YBCO-123/Hastelloy coated conductors. The measurements were carried out in a sinusoidally varying external magnetic field, with amplitudes up to 100 mT, in a frequency range of 8.5-85.4 Hz, and at a temperature of 77 K. The field was oriented perpendicularly to the face of the tapes. Sample tapes were successively patterned into the form of narrow parallel strips, by means of a photoresist lithography and chemical wet etching technique. Experimental results are discussed in the framework of existing theoretical models for energy dissipation in thin films in perpendicular AC magnetic fields

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

    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.

  4. FINITE ELEMENT ANALYSIS OF HASTELLOY C-22HS IN END MILLING

    Kadirgama, K.; Rahman, M. M .; A.R. Ismail; Bakar, R. A.

    2011-01-01

    This paper presents a finite element analysis of the stress distribution in the end milling operation of nickel-based superalloy HASTELLOY C-2000. Commercially available finite element software was used to develop the model and analyze the distribution of stress components in the machined surface of HASTELLOY C-22HS following end milling with coated carbide tools. The friction interaction along the tool-chip interface was modeled using the Coulomb friction law. It was found that the stress ha...

  5. Koch–Haaf reaction of adamantanols in an acid-tolerant hastelloy-made microreactor

    Mukai, Yu

    2011-01-01

    Summary The Koch–Haaf reaction of adamantanols was successfully carried out in a microflow system at room temperature. By combining an acid-tolerant hastelloy-made micromixer, a PTFE tube, and a hastelloy-made microextraction unit, a packaged reaction-to-workup system was developed. By means of the present system, the multigram scale synthesis of 1-adamantanecarboxylic acid was achieved in ca. one hour operation. PMID:21977213

  6. Evaluation of long-term creep properties of hastelloy XR in simulated high-temperature gas-cooled reactor helium

    Creep properties are among the important basic items of material performance for design of high temperature components of high-temperature gas-cooled reactors (HTGRs). In order to evaluate creep properties of Hastelloy XR (a modified version of the conventional Hastelloy X) developed for the High-Temperature Engineering Test Reactor (HTTR), long-term creep tests were carried out in simulated HTGR helium at 800, 900 and 1000degC. The test results up to about 50,000h showed no significant degradation in creep properties. The creep-rupture strength obtained through the long-term tests was above the level corresponding to the design allowable creep-rupture stress of the HTTR. Rupture lives could be estimated with sufficient accuracy using Larson-Miller parameter. The values of the stress exponent were 4.5 to 5.7 when the stress dependence of the steady-state creep rate was expressed in terms of the Norton equation. It was judged that dominant creep process was dislocation creep. The relationship between the steady-state creep rate and the rupture life was expressed in terms of the Monkman-Grant equation. Carburization during creep in simulated HTGR helium did not degrade creep properties of this alloy. Internally formed cavities and cracks were initiated at sites of precipitates at grain boundaries, growing nearly perpendicular to the stress axis. Creep fracture was caused by the nucleation, growth and link-up of grain boundary cavities in long-term tests. Two phases, Cr-rich carbide and Mo-rich carbide, co-existed in specimens after long-term creep tests. (author)

  7. Study of Rigid Cross-Linked PVC Foams with Heat Resistance

    Chenhui Zhao

    2012-12-01

    Full Text Available Three heat resistant cross-linked PVC foam plastics were prepared and their performances were compared with universal cross-linked PVC structural foam. The results show that these three heat resistant foams have higher glass transition temperatures (close to 100 °C than universal structural foam (83.2 °C. Compared with the universal structural foam, the three heat resistant foams show much higher decomposition temperature and better chemical stability due to the crosslinking of PVC macromolecular chains. The heat distortion temperature (HDT values of the three heat resistant foam plastics are just a little higher than that of universal structural foam. The three heat resistant foam plastics have good dimensional stability at 140 °C, and when used as core material can closely adhere to the face plates in medium temperature curing processes. Compared with universal structural foam, the three heat resistant foam plastics have slightly better mechanical properties.

  8. Heat-resistant mechanism of transgenic rape by 45Ca isotope tracer

    The Ca2+ uptake differences of the rape with heat-resistant gene and the general rape were investigated by 45Ca isotope tracer. The results showed that the rape with heat-resistant gene can strengthen the regulation of calcium absorption. The calcium regulation ability of the heat-resistant genes may be able to play in the rape aspect of the mechanism of resistance. (authors)

  9. Use of Methods of Metallurgy Sprayed and Fast Quenching Powders for Manufacturing Environments Fuel Tubes from Dispersion-Strengthened Oxides (DSO) Heat Resisting Ferritic-Martensitic Steels (P. 1)

    The technological circuit and optimum modes hardness alloying ferritic-martensitic nanodispersion yttrium oxide is considered. Results of research of structure and physicomechanical properties of the pre-production models made by a method compacting of powders of heat resisting steel EP-450 DSO are resulted. It is shown, that nanostructured steel keeps high enough residual lengthening after cold deformation on 60%

  10. Corrosion resistance of ?-solid solution and hardening ?'-phase of nickel alloys in sodium sulfate and chloride melts

    Corrosion testings of model alloys, corresponding by chemical composition to simple and complex-alloyed ?- and ?'-phases of nickel heat-resistant alloys are conducted in sodium sulfate and chloride melts. It is ascertained that heat resistant nickel alloys containing over 50 % of hardening ?'-phase, are subject to disastrous sulfide corrosion (SC). Resistance against SC alloys containing below 50 % of ?'-phase is determined by the resistance of ?-solid solution. 10 refs., 3 figs., 2 tabs

  11. Electron emission from nickel-alloy surfaces in cesium vapor

    Manda, M.; Jacobson, D.

    1978-01-01

    The cesiated electron emission was measured for three candidate electrodes for use as collectors in thermionic converters. Nickel, Inconel 600 and Hastelloy were tested with a 412 K cesium reservoir. Peak emission from the alloys was found to be comparable to that from pure nickel. Both the Inconel and the Hastelloy samples had work functions of 1.64 eV at peak emission. The minimum work functions were estimated to be 1.37 eV at a probe temperature of 750 K for Inconel and 1.40 eV for Hastelloy at 665 K. The bare work function for both alloys is estimated to be approximately the same as for pure nickel, 4.8 eV.

  12. Change of heat resistance on spore forming bacteria after irradiation

    The effect of heat resistance of endospores after gamma-irradiation were investigated for application to decontaminate microorganisms in spices or other dried food materials. D10 values of endospores dried on glass fiber filter with additives of 2% peptone + 1% glycerin were obtained to be 1.8 kGy for Bacillus pumilus, 1.1 kGy for B. cereus, 2.2 kGy for Clostridium botulinum Type A and 2.4 kGy for Cl. botulinum Type E, respectively. Non-irradiated endospores of B. pumilus and B. cereus were inactivated with 40 min of heat treatment at 100degC in water. When endospores were irradiated with 5 kGy, these bacteria were inactivated below 20 min of heating at 100degC in water. In the case of Cl. botulinum Type A and Type E, non-irradiated endospores were inactivated with 30 min of heat treatment at 100degC in water, and irradiated endospores at 5 kGy were inactivated below 15 min of heating. However, all of these bacteria could not inactivate endospores even after heating more than 2 hours at 100degC in dry condition or 80degC in water, and decreased a little of necessary times for inactivation of heat treatment after irradiation at 5 kGy. (author)

  13. Heat-Resistant Crack-Free Superhydrophobic Polydivinylbenzene Colloidal Films.

    Wang, Zefeng; Ye, Weiwei; Luo, Xinran; Wang, Zhonggang

    2016-03-29

    Highly cross-linked poly(divinylbenzene) (PDVB) spherical colloidal particles with nano-, submicron-, and micron-sizes of 157.2 nm, 602.1 nm, and 5.1 μm were synthesized through emulsion and dispersion polymerization methods. The influences of particle size on the surface morphology, roughness, superhydrophobicity, and critical cracking thickness of colloidal films were studied in detail. The results show that PDVB colloidal films possess large water contact angle (CA) over 151°, belonging to superhydrophobic materials. Moreover, it is interesting to observe that the highly cross-linked network structure leads to PDVB film's excellent heat-resistance. The CA and rough surface morphology remain nearly unchanged after thermal-treatment of films at 150 °C for 24 h. In addition, no cracks were observed in films with thicknesses up to 8.1 μm, exceeding most of polymer and inorganic particle films reported in the literature. The simple and scalable preparation method, low-cost, superhydrophobicity, and excellent thermal stability endow the PDVB colloidal films with promising applications in advanced coating fields, especially when employed in the high-temperature service environment. PMID:26986041

  14. Studies Concerning Heat-Resisting Additives for Bitumens

    Livia Groll

    2008-01-01

    Full Text Available The improvement of causeway’s bitumen adhesiveness is becoming a current practice in our country, especially when is used acid (siliceous aggregate. One of the most important properties of bitumen is its adhesiveness to aggregate, and this property determine the using of bitumen in causeways area. Usually the adhesiveness is defined as the capacity of a binder to cover an aggregate without dispersing itself when touching the water or the traffic aggressions. Therefore, the adhesiveness additives are products that improve the adhesiveness of the bitumen to a certain aggregate. The used additives – ADETEN type (A01 and A03 have a high stocking stability, a low toxicity degree toward the amine, diamine, polyamine-based additives and are liquid products perfectly compatible with all bitumens and easy to use, in comparison to the paste or solid additives, which must be made liquid to be used. But a very important condition, which must be fulfilled by these promoters is the heat-resisting condition.

  15. Critical experiments of the self-consistent model for polycrystalline Hastelloy-X

    Shi, Shixiang; Walker, Kevin P.; Jordan, Eric H.

    1991-01-01

    A viscoplastic constitutive model is presented for the estimation of the overall mechanical response of Hastelloy-X polycrystalline metals from a knowledge of single crystal behavior. The behavior of polycrystal is derived from that of single crystals using a self-consistent formulation. The single crystal behavior which has been used was developed by summing postulated slip on crystallographic slip systems. The plasticity and creep are treated coupledly using unified viscoplastic model which includes the interaction effects between rapid and slow deformation at elevated temperature. The validity of the model is directly tested by experiments on Hastelloy-X in both single crystal and polycrystalline versions.

  16. An investigation into crystalline phases and nano structural and mechanical properties of HH heat resistant stainless steels

    M Hosseini

    2015-12-01

    Full Text Available In the present work, the effects of different casting parameters including pouring temperature and cooling rate on stainless steel structures and mechanical properties of heat resistant alloy (HH were studied. Mo nanoparticles were synthesized through sol-gel method and were coated on the stainless steel device using spin-coating method. The effect of coating layer on the device was studied by using XRD (X-Ray Diffraction and FT-IR (Fourier Transform Infra red and SEM (Scanning Electron Microscopy techniques. The obtained results indicated an enhancement of corrosion, surface abrasion protection without changing metal surface structure, and a reduction of leakage current through the stainless steel device. Furthermore, pouring temperature and cooling rate increase caused a fine grain structure to be acquired with less carbides and better distribution in the austenitic matrix.

  17. Analyzing the effect of cutting parameters on surface roughness and tool wear when machining nickel based hastelloy - 276

    Machining parameters has an important factor on tool wear and surface finish, for that the manufacturers need to obtain optimal operating parameters with a minimum set of experiments as well as minimizing the simulations in order to reduce machining set up costs. The cutting speed is one of the most important cutting parameter to evaluate, it clearly most influences on one hand, tool life, tool stability, and cutting process quality, and on the other hand controls production flow. Due to more demanding manufacturing systems, the requirements for reliable technological information have increased. For a reliable analysis in cutting, the cutting zone (tip insert-workpiece-chip system) as the mechanics of cutting in this area are very complicated, the chip is formed in the shear plane (entrance the shear zone) and is shape in the sliding plane. The temperature contributed in the primary shear, chamfer and sticking, sliding zones are expressed as a function of unknown shear angle on the rake face and temperature modified flow stress in each zone. The experiments were carried out on a CNC lathe and surface finish and tool tip wear are measured in process. Machining experiments are conducted. Reasonable agreement is observed under turning with high depth of cut. Results of this research help to guide the design of new cutting tool materials and the studies on evaluation of machining parameters to further advance the productivity of nickel based alloy Hastelloy - 276 machining.

  18. Reduction in mechanical anisotropy through high temperature heat treatment of Hastelloy X processed by Selective Laser Melting (SLM)

    Etter, T.; Kunze, K.; Geiger, F.; Meidani, H.

    2015-04-01

    Selective Laser Melting (SLM) is an additive manufacturing technology used to directly produce metallic parts from thin powder layers. To evaluate the anisotropic mechanical properties, tensile test specimens of the Ni-base alloy Hastelloy X were built with the loading direction oriented either parallel (z-specimens) or perpendicular to the build-up direction (xy- specimens). Specimens were investigated in the “as-built” condition and after high temperature heat treatment. Tensile tests at room temperature and at 850°C of “as-built” material have shown different mechanical properties for z- and xy-specimens. The anisotropy is reflected in the Young's modulus, with lower values measured parallel to the build-up direction. It is shown that the anisotropy is significantly reduced by a subsequent recrystallization heat treatment. The characterization of microstructural and textural anisotropy was done by Electron Back Scatter Diffraction (EBSD) analysis. Predictions of Young's modulus calculated from the measured textures compare well with the data from tensile tests.

  19. FY 1998 annual report on the study on solidification process of hot, heat-resistant metal melts; 1998 nendo tainetsu kinzoku koon yueki no gyoko katei no kenkyu chosa hokokusho

    NONE

    1999-03-01

    Described herein are results of the studies on basic aspects of solidification process of hot, heat-resistant metal melts under a microgravity atmosphere, its applicability to industrial purposes, production of new metallic structures by precision casting and supercooling solidification of the heat-resistant, metal alloy parts, and evaluation techniques therefor. In the supercooling solidification of Al, its purity greatly determines the crystal morphology. The single crystal can be produced under a microgravity when it is 99.9% pure. The supercooling solidification under a microgravity can give an Al-Pb alloy structure of uniform dendrite structure both on the surface and inside, free of gravity-caused segregation of Pb. The welding problems caused by Al{sub 2}O{sub 3} present in the Al are solved. The study also clarifies the effects of the microgravity atmosphere in the spot welding by a pulsed YAG laser on, e.g., melting characteristics, welding phenomena and formation of welding defects. The basic knowledge obtained is expected to contribute to, e.g., precision casting and welding of heat-resistant alloys, and creation of new alloys. (NEDO)

  20. Microstructure evolution during service exposure of two cast, heat-resisting stainless steels - HP-Nb modified and 20-32Nb

    The repair weldability of two types of heat-resistant austenitic stainless steel castings, HP-Nb modified alloys and 20-32Nb alloys, has been evaluated after extended service exposure of these materials at temperatures on the order of 815 deg. C (1500 deg. F). The initial part of this investigation has focused on characterization of the microstructure of these alloys after service exposure times of up to 12 years. Microstructure evolution from the as-cast condition to the service-exposed condition is described. In the as-cast condition, both eutectic NbC and Cr-rich M7C3 carbides were observed in the HP-Nb alloys. In contrast, only eutectic NbC carbides were present in the as-cast 20-32Nb alloys due to a significantly higher atomic ratio of Nb/C as compared to the HP-Nb alloys. In the service-exposed condition, an Ni-Nb silicide and Cr-rich M23C6 were identified in both alloys. The HP-Nb alloys exhibited a much higher total volume fraction of microconstituents than the 20-32Nb alloys and the M23C6 phase was more prevalent than Ni-Nb silicide. In contrast, the Ni-Nb silicide was dominant in the service-exposed 20-32Nb alloys. This difference resulted in a significant increase in the repair welding liquation cracking susceptibility of the 20-32Nb service-exposed alloy

  1. The substitution of molybdenum by vanadium in high alloy castings

    The possibility of substituting molybdenum with vanadium both partially and completely in high alloy castings because of vanadium's availability in Southern Africa and its relatively lower cost, was studied. The high alloy castings used in the investigation include: ACl Types CF-8M and CG-8M, alloys similar to ACl Type CN-7M and the proprietory grade nickel-base alloys Hastelloy B and Hastelloy C. They were investigated, with respect to general corrosion resistance in phosphoric, sulphuric and hydrochloric acid and localised attack in chloride media, using potentiodynamic and immersion tests conforming to ASTM standards. Vanadium emerges as an inadequate substitute except with the cast austenitic stainless steels where it may find limited application as a partial substitute

  2. Effects of high temperature environment on creep properties of hastelloy X

    In order to clarify the creep properties of Hastelloy X, that is one of the materials discussed for use in VHTR, in helium at extremely high temperature, creep and rupture tests in helium and in air were carried out on Hastelloy X at temperatures of 9000C and 10000C. No remarkable differences between primary and secondary creep rates in helium and those in air were observed. On the other hand, the initiation of tertiary creep was slower and the period of tertiary creep shorter in helium than in air. Moreover, rupture ductilities decrease in helium as compared with those in air. Those differences are considered to be dependent of less internal oxidation and sharper crack tips in helium than in air. (author)

  3. Heat treatment of nickel alloys

    A heat treating process is described that can be used to produce desired combinations of strength, ductility, and fabricability characteristics in heat resistant age-hardenable alloys having precipitation-hardening amounts of niobium, titanium, and/or tantalum in a nickel-containing matrix. (U.S.)

  4. Creep test of Hastelloy X for use as the components of OGL-1 in helium environment

    Hastelloy X is used for inner and flow tubes of OGL-1 (Oarai Gas Loop No.1) installed in JMTR. The tubes were produced by a special procedure, BTA (Boring and Trepanning Association), because of their form of thin wall thickness and large diameter. By this procedure the central part of a forged bar was hollowed out. Creep rupture data for the tube material have been obtained up to 15,000 hr in the longest test period in air. In practice, since the tubes were to be exposed to helium gas, the material was tested in a simulated helium environment. The results obtained were compared with the air data and also the other set of creep data accumulated with Hastelloy XR. The latter data contain those on tube and bar materials and have been provided for design of HTGR. The results obtained by the test at 900 deg C in helium to the maximum test duration up to 10,000 hr yielded the following conclusions; (1) Hastelloy X for OGL-1 (OGL-HX hereafter) showed longer rupture life accompanied by smaller cracks in helium than that tested in air. (2) Rupture life was shorter in the following order; the tube material of Hastelloy HR (HR hereafter), the bar material of XR and OGL-HX. (3) Rupture elongation was the highest in the bar material of XR and minimum in tube material of XR. The value OGL-HX was middle of the two. (4) Creep rate was lowest for OGL-HX, however in the lower stresses range the value of the tube material of XR approached to that of OGL-HX. The results were discussed from the view point of minor impurities, production processes and microstructure eg. annealing twin. (author)

  5. Creep-rupture tests of internally pressurized Hastelloy-X tubes

    Gumto, K. H.; Colantino, G. J.

    1973-01-01

    Seamless Hastelloy-X tubes with 0.375-in. outside diameter and 0.025-in. wall thickness were tested to failure at temperatures from 1400 to 1650 F and internal helium pressures from 800 to 1800 psi. Lifetimes ranged from 58 to 3600 hr. The creep-rupture strength of the tubes was from 20 to 40 percent lower than that of sheet specimens. Larson-Miller correlations and photomicrographs of some specimens are presented.

  6. Microstructures, mechanical properties and corrosion resistance of Hastelloy C22 coating produced by laser cladding

    Wang, Qin-Ying; Zhang, Yang-Fei [Department of Materials Science and Engineering, HEDPS, Center for Applied Physics and Technology, LTCS, College of Engineering, Peking University, Beijing 100871 (China); Bai, Shu-Lin, E-mail: slbai@pku.edu.cn [Department of Materials Science and Engineering, HEDPS, Center for Applied Physics and Technology, LTCS, College of Engineering, Peking University, Beijing 100871 (China); Liu, Zong-De [Key Laboratory of Condition Monitoring and Control for Power Plant Equipment of Ministry of Education, North China Electric Power University, Beijing 102206 (China)

    2013-03-15

    Highlights: ► Hastelloy C22 coatings were prepared by diode laser cladding technique. ► Higher laser speed resulted in smaller grain size. ► Size-effect played the key role in the hardness measurements by different ways. ► Coating with higher laser scanning speed displayed higher nano-scratch resistance. ► Small grain size was beneficial for improvement of coating corrosion resistance. -- Abstract: The Hastelloy C22 coatings H1 and H2 were prepared by laser cladding technique with laser scanning speeds of 6 and 12 mm/s, respectively. Their microstructures, mechanical properties and corrosion resistance were investigated. The microstructures and phase compositions were studied by metallurgical microscope, scanning electron microscope and X-ray diffraction analysis. The hardness and scratch resistance were measured by micro-hardness and nanoindentation tests. The polarization curves and electrochemical impedance spectroscopy were tested by electrochemical workstation. Planar, cellular and dendritic solidifications were observed in the coating cross-sections. The coatings metallurgically well-bonded with the substrate are mainly composed of primary phase γ-nickel with solution of Fe, W, Cr and grain boundary precipitate of Mo{sub 6}Ni{sub 6}C. The hardness and corrosion resistance of steel substrate are significantly improved by laser cladding Hastelloy C22 coating. Coating H2 shows higher micro-hardness than that of H1 by 34% and it also exhibits better corrosion resistance. The results indicate that the increase of laser scanning speed improves the microstuctures, mechanical properties and corrosion resistance of Hastelloy C22 coating.

  7. Electrochemical Impedance Spectroscopy Of Metal Alloys

    Macdowell, L. G.; Calle, L. M.

    1993-01-01

    Report describes use of electrochemical impedance spectroscopy (EIS) to investigate resistances of 19 alloys to corrosion under conditions similar to those of corrosive, chloride-laden seaside environment of Space Transportation System launch site. Alloys investigated: Hastelloy C-4, C-22, C-276, and B-2; Inconel(R) 600, 625, and 825; Inco(R) G-3; Monel 400; Zirconium 702; Stainless Steel 304L, 304LN, 316L, 317L, and 904L; 20Cb-3; 7Mo+N; ES2205; and Ferralium 255. Results suggest electrochemical impedance spectroscopy used to predict corrosion performances of metal alloys.

  8. Creep Behavior at 1273 K (1000 °C) in Nb-Bearing Austenitic Heat-Resistant Cast Steels Developed for Exhaust Component Applications

    Zhang, Yinhui; Li, Mei; Godlewski, Larry A.; Zindel, Jacob W.; Feng, Qiang

    2016-05-01

    A series of Nb-bearing austenitic heat-resistant cast steels with variations of N/C ratios were investigated, and the morphological change of Nb(C,N) from faceted blocks, mixed flake-blocks to "Chinese-script" was observed as N/C ratios decreased. The creep behavior of these alloys was studied at 1273 K (1000 °C), and the longest creep life and lowest creep rate occurred in model alloys with script Nb(C,N). Residual δ-ferrites and (Cr,Fe)23C6 were adverse to creep properties. This work indicates that the control of N/C ratio is required for the as-cast microstructural strengthening.

  9. Heat-resistant fungi of importance to the food and beverage industry.

    Tournas, V

    1994-01-01

    Spoilage of pasteurized and canned fruit and fruit products caused by heat-resistant molds have been reported repeatedly in recent years. Species most commonly implicated in fruit and fruit product disintegration are Byssochlamys fulva, Byssochlamys nivea, Neosartorya fischeri, Talaromyces flavus, and Eupenicillium brefeldianum. These organisms are saprophytic rather than parasitic and usually contaminate fruits on or near the ground. They can survive heat treatments used for fruit processing and can grow and spoil the products during storage at room temperature, which results in great economic losses. Mold heat resistance is attributed to the formation of sexual spores, ascospores. Ascospores have a wide range of heat resistance, depending on species, strain, age of organism, heating medium, pH, presence of sugars, fats, and acids in heating medium, growth conditions, etc. The mechanism(s) of thermoresistance are not clear; probably some very stable compound(s) critical to germination and outgrowth are present in the heat-resistant ascospores. Besides spoilage, the heat-resistant molds produce a number of toxic secondary metabolites, such as byssotoxin A; byssochlamic acid; the carcinogen, patulin, the tremorgenic substances, fumitremorgin A and C, and verruculogen; fischerin, which caused fatal peritonitis in mice; and eupenifeldin, a compound possessing cytotoxicity as well as in vivo antitumor activity. Growth of heat-resistant fungi can be controlled by lowering the water activity, adding sulfur dioxide, sorbate, or benzoate; washing of fruits in hypochlorite solution before heat treatment reduces the number of ascospores and makes the heat destruction more successful. More research is needed to elucidate the mechanism(s) of thermoresistance and develop new methods for the complete inactivation of resistant ascospores. PMID:7857517

  10. Phototransduction genes are up-regulated in a global gene expression study of Drosophila melanogaster selected for heat resistance

    Nielsen, Morten Muhlig; Sørensen, Jesper Givskov; Kruhøffer, Mogens; Justesen, Just; Loeschcke, Volker

    2006-01-01

    The genetic architecture underlying heat resistance remains partly unclear despite the well-documented involvement of heat shock proteins (Hsps). It was previously shown that factors besides Hsps are likely to play an important role for heat resistance. In this study, gene expression arrays were used to make replicate measurements of gene expression before and up to 64 hours after a mild heat stress treatment, in flies selected for heat resistance and unselected control flies, to identify gen...

  11. The one-parameter-model - a constitutive equation applied to a heat resistant alloy

    In the present work a constitutive model earlier developed and used to predict experimental results of hot tests and fatigue tests from creep experiments of metallic materials were modified to comply with the properties of a high temperature resistant material. The improved model accounts for the properties of a material developing a density and a structure of dislocation lines which are capable of interactions with particles (carbides) from a second phase. The time and temperature dependent evolution of the carbide structure has been described by an equation which explains the formation of seeds as well as their growths (Ostwald ripening). The extended model was applied to Incoloy 800H which is known to develop a carbide structure. Therefore hot tensile and fatigue tests, creep and relaxation experiments using the heats ADU and BAK (KFA specifications) at temperature between 800deg C and 900deg C were performed including both solution treated specimens and specimens heat treated for 10, 100 and 1000 hours. As compared with the results from tensile tests where the carbide structures play a subordinated role, alternately, these structures have a decisive influence on the creep properties of specimens during the primary creep phase, i.e. low stresses and high temperatures. (orig.)

  12. Broadening of temperature range when testing heat-resistant alloys for high-temperature chloride corrosion

    Results of corrosion resistance of materials with nickel, iron and chromium base (EhK-9VD, Kh18N10T and VKh-2K) in sodium chloride, equimolar mixture of sodium and potassium chlorides and internary eutectics (48.7 % of MgCl2 + 38.2 % of KCl+13.1 % of NaCl) at 400-900 deg C temperature and 20 hour exposure are presented. it is shown that application of ternary mixture instead of sodium chloride and binary chloride mixture indicated allows one to reduce the temperature of testing for chloride corrosion resistance down to 410 deg C, and thus to broaden the testing temperature range by 250-400 deg C

  13. Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

    Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 °C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (μ-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from μ-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 °C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys

  14. Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

    Liu, Min, E-mail: liumin@sinap.ac.cn; Zheng, Junyi; Lu, Yanling, E-mail: luyanling@sinap.ac.cn; Li, Zhijun; Zou, Yang; Yu, Xiaohan; Zhou, Xingtai, E-mail: zhouxingtai@sinap.ac.cn

    2013-09-15

    Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (?-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from ?-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys.

  15. Investigation on corrosion behavior of Ni-based alloys in molten fluoride salt using synchrotron radiation techniques

    Liu, Min; Zheng, Junyi; Lu, Yanling; Li, Zhijun; Zou, Yang; Yu, Xiaohan; Zhou, Xingtai

    2013-09-01

    Ni-based alloys have been selected as the structural materials in molten-salt reactors due to their high corrosion resistance and excellent mechanical properties. In this paper, the corrosion behavior of some Ni-based superalloys including Inconel 600, Hastelloy X and Hastelloy C-276 were investigated in molten fluoride salts at 750 C. Morphology and microstructure of corroded samples were analyzed using scanning electron microscope (SEM), synchrotron radiation X-ray microbeam fluorescence (?-XRF) and synchrotron radiation X-ray diffraction (SR-XRD) techniques. Results from ?-XRF and SR-XRD show that the main depleted alloying element of Ni-based alloys in molten fluoride salt is Cr. In addition, the results indicate that Mo can enhance the corrosion resistance in molten FLiNaK salts. Among the above three Ni-based alloys, Hastelloy C-276 exhibits the best corrosion resistance in molten fluoride salts 750 C. Higher-content Mo and lower-content Cr in Hastelloy C-276 alloy were responsible for the better anti-corrosive performance, compared to the other two alloys.

  16. Properties of super alloys for high temperature gas cooled reactor

    The existing data on the properties at high temperature in helium gas of iron base super alloys. Incoloy-800, -802 and -807, nickel base super alloys, Hastelloy-X, Inconel-600, -617 and -625, and a casting alloy HK-40 were collectively evaluated from the viewpoint of the selection of material for HTGRs. These properties include corrosion resistance, strength and toughness, weldability, tube making, formability, radioactivation, etc. Creep strength was specially studied, taking into consideration the data on the creep characteristics in the actual helium gas atmosphere. The necessity of further long run creep data is suggested. Hastelloy-X has completely stable corrosion resistance at high temperature in helium gas. Incoloy 800 and 807 and Inconel 617 are not preferable in view of corrosion resistance. The creep strength of Inconel 617 extraporated to 1,000 deg C for 100,000 hours in air was the greatest rupture strength of 0.6 kg/mm2 in all above alloys. However, its strength in helium gas began to fall during a relatively short time, so that its creep strength must be re-evaluated in the use for long time. The radioactivation and separation of oxide film in primary construction materials came into question, Inconel 617 and Incoloy 807 showed high induced radioactivity intensity. Generally speaking, in case of nickel base alloys such as Hastelloy-X, oxide film is difficult to break away. (Iwakiri, K.)

  17. Microstructural stability of 9-12%Cr ferrite/martensite heat-resistant steels

    Yan, Wei; Wang, Wei; Shan, Yi-Yin; Yang, Ke

    2013-03-01

    The microstructural evolutions of advanced 9-12%Cr ferrite/martensite heat-resistant steels used for power generation plants are reviewed in this article. Despite of the small differences in chemical compositions, the steels share the same microstructure of the as-tempered martensite. It is the thermal stability of the initial microstructure that matters the creep behavior of these heat-resistant steels. The microstructural evolutions involved in 9-12%Cr ferrite heat-resistant steels are elaborated, including (1) martensitic lath widening, (2) disappearance of prior austenite grain boundary, (32) emergence of subgrains, (4) coarsening of precipitates, and (5) formation of new precipitates, such as Laves-phase and Z-phase. The former three microstructural evolutions could be retarded by properly disposing the latter two. Namely improving the stability of precipitates and optimizing their size distribution can effectively exert the beneficial influence of precipitates on microstructures. In this sense, the microstructural stability of the tempered martensite is in fact the stability of precipitates during the creep. Many attempts have been carried out to improve the microstructural stability of 9-12%Cr steels and several promising heat-resistant steels have been developed.

  18. Creep behaviour of heat-resistant power plant steels under rectangular cyclic stress

    The modified life component rule is suitable for describing, to a great extent, the rectangular cyclic creep behaviour of a series of typical heat-resistant steels. In order to predict fracture time or expansion boundary time, the data of a stress cycle are necessary in addition to the normal creep values of a steel. (orig.)

  19. Transparent Heat-Resistant PMMA Copolymers for Packing Light-Emitting Diode Materials

    Shu-Ling Yeh; Chao-Yuan Zhu; Shiao-Wei Kuo

    2015-01-01

    Transparent and heat-resistant poly(methyl methacrylate) copolymers were synthesized by bulk polymerizing methyl methacrylate (MMA), isobornyl methacrylate (IBMA), and methacrylamide (MAA) monomers. Copolymerization was performed using a chain transfer agent to investigate the molecular weight changes of these copolymers, which exhibited advantages including a low molecular weight distribution, excellent optical properties, high transparency, high glass transition temperature, low moisture a...

  20. Creep fatigue behavior of heat resistant steels under service-type strain cycling at high temperature

    On three typical heat resistant steels the creep fatigue behaviour is investigated up to about 10000 h test duration using a service-type strain cycle. In a creep fatigue life analysis the cyclic deformation behaviour and the applicability of the generalized damage accumulation rule are investigated and possibilities of long-term creep fatigue prediction are studied. (orig.)

  1. FY 1997 report on the study on solidification process of high-temperature melt of heat resistant metals; 1997 nendo chosa hokokusho (tainetsu kinzoku koon yueki no gyoko katei no kenkyu)

    NONE

    1998-03-01

    Study was made on a solidification process of metal melt under micro-gravity condition in an underground non-gravity experiment center, considering that improvement of the heat resistance of turbine blades for jet engines and power generation gas turbines contributes to prevention of global warming through improvement of thermal engine efficiencies and consumption reduction of precious fossil fuel. Study was made on a simulation program and precise measurement of thermal properties for precision casting of heat-resistant alloy members. Study was also made on Al and Zn alloys and their welding for production and evaluation technologies of new metal textures by supercooling solidification. Some issues for strongly desired improvement of a simulation program for precision casting were clarified. In addition, since thermal property data of practical heat-resistant polyalloy members are poor, data and measurement method for precision casting were clarified. It was also suggested that basic elucidation of the solidification process under micro- gravity condition is possible. 34 refs., 41 figs., 5 tabs.

  2. Extreme Heat Resistance of Food Borne Pathogens Campylobacter jejuni, Escherichia coli, and Salmonella typhimurium on Chicken Breast Fillet during Cooking

    de Jong, Aarieke E I; van Asselt, Esther D; Zwietering, Marcel H; Nauta, Maarten J; de Jonge, Rob

    2012-01-01

    cooking enlarged the heat resistance of the food borne pathogens. Additionally, a high challenge temperature or fast heating rate contributed to the level of heat resistance. The data were used to assess the probability of illness (campylobacteriosis) due to consumption of chicken fillet as a function of...

  3. Importance of billet microstructure in the hot extrusion of 2% Ti-Hastelloy N

    Braski, D. N.; McDonald, R. E.

    1977-05-01

    The successful hot extrusion of billets of Ti-Hastelloy N (13 percent Mo, 7 percent Cr, 2 percent Ti, 0.06 percent C, 87.94 percent Ni) into tube shells and followed by cold drawing into 19-mm-OD (0.75-in.) tubing depends largely on the billet microstructure. It was imperative that the preheat annealing treatment given directly before hot extrusion be designed to uniformly dissolve most of the MC-type carbide particles. A 101.6-mm-diam x 304.8-mm-long (4 x 12-in.) billet required a preheat of 4 hr at 1533/sup 0/K.

  4. Corrosion tests of 316L and Hastelloy C-22 in simulated tank waste solutions

    Both the 316L stainless steel and Hastelloy C-22 gave satisfactory corrosion performance in the simulated test environments. They were subjected to 100 day weight loss corrosion tests and electrochemical potentiodynamic evaluation. This activity supports confirmation of the design basis for the materials of construction of process vessels and equipment used to handle the feed to the LAW-melter evaporator. BNFL process and mechanical engineering will use the information derived from this task to select material of construction for process vessels and equipment

  5. Fatigue crack growth characteristic of hastelloy X in air at elevated temperature

    Fatigue crack growth tests on Hastelloy X were conducted in air at 7500C and 9000C. Varied contribution of creep was given by choosing the stress ratio levels between 0 to 1. Three fracture modes were observed, i.e. transgranular fatigue mode, intergranular creep mode and transition from transgranular to intergranular mode, according to the degree of contribution of creep effect. In handling of the crack growth rate data with fracture mechanical parameter, da/dN-ΔK relation, da/dN-ΔJ relation and da/dt-j relation were found to be appropreate for the three modes respectively. (author)

  6. Tendency to amorphous state formation in V-Zr-Mo system alloys

    Investigation into conditions of V-Zr-Mo system alloys production and determination of amorphization intervals under gaseous deposition is conducted. 20 ?m thick foils of ternary alloys in amorphous state, stable under heating up to 900 deg C, are produced. It is shown, that vanadium introduction allows one to increase the alloy ductility with the material heat resistance being preserved

  7. Heat-resistance of Hamigera avellanea and Thermoascus crustaceus isolated from pasteurized acid products.

    Scaramuzza, Nicoletta; Berni, Elettra

    2014-01-01

    Products containing sugar or fruit derivatives are usually subjected to a pasteurization process that can anyway be ineffective to kill ascospores from heat-resistant molds. Although the most occurring and economically relevant heat-resistant species belong to Byssochlamys, Neosartorya, Talaromyces, and Eupenicillium genera, an increasing number of uncommon heat-resistant isolates have been recently detected as spoiling microorganisms in such products. Since Hamigera spp. and Thermoascus spp. were those more frequently isolated at SSICA, heat resistance of Hamigera avellanea and Thermoascus crustaceus strains from pasteurized acid products was studied in apple juice, in blueberry and grape juice and in a buffered glucose solution. Data obtained from thermal death curves and statistical elaboration of raw data showed that D values of H. avellanea may vary between 11.11 and 66.67 min at 87°C, between 4.67 and 13.51 at 90°C, and between 0.43 and 1.52 min at 95°C. Similarly, D values of T. crustaceus may vary between 18.52 and 90.91 min at 90°C, between 2.79 and 19.23 at 93°C, and between 1.11 and 2.53 min at 95°C. For both strains studied, the z-values calculated from the decimal reduction time curves did not prove to be significantly influenced by the heating medium, that being 4.35°C, 5.39°C or 5.27°C for H. avellanea and 4.42°C, 3.69°C or 3.37°C for T. crustaceus, respectively in apple juice, in blueberry and grape juice or in the buffered glucose solution. Considering the pasteurization treatments industrially applied to fruit-based foods, the variation of thermal parameters does not seem to be a possible way to avoid product spoilage by these two species and only good practices applied to reduce the original load of heat-resistant fungi can help producers to prevent losses in contaminated finished products, as usually happens for other heat resistant molds. PMID:24239977

  8. Seizure and wear characteristics of Hastelloy XR and titanium nitride coating in high temperature condition

    A concentric hot gas duct between the reactor core of the High Temperature engineering Test Reactor (HTTR) and primary heat exchangers consists of a pressure tube, inner tube, liner and so on. Axial and radial thermal expansion difference between the liner and inner tube caused by the different temperature is absorbed by liner slide joints and by liner supports and spacers respectively. We have proposed to coat Titanium Nitride (TiN) on the surface of the liner slide joints, supports and spacers using the thermal CVD (Chemical Vapor Deposition) method in order to prevent their seizure and excessive wear at service temperature of 950degC. Seizure and wear characteristics of Hastelloy XR and TiN coating in high temperature condition of 950degC were studied experimentally. As a result, it has been confirmed that TiN coating film of 3μm on the surface of Hastelloy XR is sufficient to prevent seizure and excessive wear of the liner slide joints, supports and spacers during the life time of the HTTR. TiN coating by their thermal CVD method was adopted as the coating method for the liner slide joints, supports and spacers of the HTTR. (author)

  9. Changes of the permeability of hydrogen of heat resisting metallic materials caused by thin oxide barriers on the surface

    The permeability of hydrogen and tritium through oxide surface layers of Incoloy 800, Incoloy 800H, Incoloy 802, Incoloy 807, IN 586, Inconel 617, Hastelloy X, HK 40, Manaurite 36X, IN 519, IN 638 and IN 643 was studied dependent on temperature (600-10000C) and hydrogen pressure (1-20 bar). (TWO)

  10. Effect of moisture on corrosion of Ni-based alloys in molten alkali fluoride FLiNaK salt environments

    Ouyang, Fan-Yi; Chang, Chi-Hung; You, Bo-Chien; Yeh, Tsung-Kuang; Kai, Ji-Jung

    2013-06-01

    We investigated the corrosion characteristics on several selected alloys at 600 and 700 °C in FLiNaK molten salts with different moisture contents. Hastelloys-N and Hastelloys-B3 exhibited better corrosion resistances, while Haynes 263 showed the poorest corrosion resistance. The mass loss of the tested alloys is primarily determined by the purity of FLiNaK salts; however, the effect of temperature becomes more important on the mass loss of the tested alloys in the non-purified FLiNaK salts. When the residual moisture is present in the FLiNaK salts, the mass losses of the tested alloys varied linearly with original Cr content plus one-third of Mo content. The results of structural characterization revealed that the tested alloys in the FLiNaK salts with higher moisture content would aggravate intergranular corrosion and pitting.

  11. Polyphasic taxonomy of the heat resistant ascomycete genus Byssochlamys and its Paecilomyces anamorphs

    Samson, R.A.; Houbraken, J.; Varga, J.; Frisvad, Jens Christian

    2009-01-01

    Byssochlamys and related Paecilomyces strains are often heat resistant and may produce mycotoxins in contaminated pasteurised foodstuffs. A comparative study of all Byssochlamys species was carried out using a polyphasic approach to find characters that differentiate species and to establish...... accurate data on potential mycotoxin production by each species. Phylogenetic analysis of the ITS region, parts of the P-tubulin and calmodulin genes, macro- and micromorphological examinations and analysis of extrolite profiles were applied. Phylogenetic analyses revealed that the genus Byssochlamys...

  12. Bacterial spore heat resistance correlated with water content, wet density, and protoplast/sporoplast volume ratio.

    Beaman, T C; Greenamyre, J T; Corner, T R; Pankratz, H. S.; Gerhardt, P

    1982-01-01

    Five types of dormant Bacillus spores, between and within species, were selected representing a 600-fold range in moist-heat resistance determined as a D100 value. The wet and dry density and the solids and water content of the entire spore and isolated integument of each type were determined directly from gram masses of material, with correction for interstitial water. The ratio between the volume occupied by the protoplast (the structures bounded by the inner pericytoplasm membrane) and the...

  13. Heat resistance of bacterial spores correlated with protoplast dehydration, mineralization, and thermal adaptation.

    Beaman, T C; Gerhardt, P

    1986-01-01

    Twenty-eight types of lysozyme-sensitive spores among seven Bacillus species representative of thermophiles, mesophiles, and psychrophiles were obtained spanning a 3,000-fold range in moist-heat resistance. The resistance within species was altered by demineralization of the native spores to protonated spores and remineralization of the protonated spores to calcified spores and by thermal adaptation at maximum, optimum, and minimum sporulation temperatures. Protoplast wet densities, and there...

  14. Influence of Dispersed Heat-Resistant Additives on Ignition and Combustion of Heterogeneous Systems

    Arkhipov V.A.

    2015-01-01

    Full Text Available The results of experimental studies of the effect of dispersion of heat-resistant additives powders on ignition and combustion of heterogeneous condensed systems. The method of measuring the time delay ignition conductive and radiant heating, and combustion rate at atmospheric pressure. The effect of additives powders of boron, silicon and titanium dioxide on the ignition and combustion of heterogeneous condensed systems.

  15. Influenced prior loading on the creep fatigue damage accumulation of heat resistant steels

    On two heat resistant power plant steels the influence of prior strain cycling on the creep rupture behaviour and the influence of prior creep loading on the strain cycling behaviour is investigated. These influences concern the number of cycles to failure and the rupture time being the reference values of the generalized damage accumulation rule and they are used for a creep fatigue analysis of the results of long term service-type strain cycling tests. (orig.)

  16. Fermi level of carriers in the volume filling defects structure based on heat-resistant metals

    Marenkov, V.I.

    2011-01-01

    The volume filling defects structure based on metals are widely used in modern nan- otechnology, especially when creating high temperature sensors and structural elements based on metal foams [1]. The development of contactless and nondestructive methods for diagnosis and test control parameters of multiply connected matrix base material is a very important and interesting aspect of the application [2]. In a heat-resistant metal with the volume filling defects (VFD) (micro-...

  17. Agni's fungi: heat-resistant spores from the Western Ghats, southern India.

    Suryanarayanan, T S; Govindarajulu, M B; Thirumalai, E; Reddy, M Sudhakara; Money, Nicholas P

    2011-09-01

    This study concerns the thermotolerance of spores of mesophilic fungi isolated from a tropical semi-arid habitat subject to dry season fire in the Western Ghats, southern India. Among 25 species of Ascomycota isolated from leaf litter, nine were able to grow after incubation in a drying oven for 2h at 100C; the spores of two of these species survived 2h incubation at 110C, and one survived exposure to 115C for 2h. The range of thermotolerance among mesophilic fungi isolated from the leaf litter was surprising: filamentous fungi from other habitats, including species that colonize scorched vegetation after fires and thermophilic forms occurring in self-heating plant composts, cannot survive even brief exposure to such high temperatures. It is possible that the exceptional heat resistance of the Indian fungi is related to adaptations to surviving fires. Genetic analysis of the physiological mechanisms of heat resistance in these fungi offers prospects for future biotechnological innovations. The discovery of extreme thermotolerance among common saprotrophs shows that this physiological trait may be more widespread than recognized previously, adding to concern about the evolution of opportunistic pathogens on a warmer planet. The fungi in this study are among the most heat-resistant eukaryotes on record and are referred to here as 'Agni's Fungi', after the Hindu God of Fire. PMID:21872180

  18. Significant effect of Ca2+ on improving the heat resistance of lactic acid bacteria.

    Huang, Song; Chen, Xiao Dong

    2013-07-01

    The heat resistance of lactic acid bacteria (LAB) has been extensively investigated due to its highly practical significance. Reconstituted skim milk (RSM) has been found to be one of the most effective protectant wall materials for microencapsulating microorganisms during convective drying, such as spray drying. In addition to proteins and carbohydrate, RSM is rich in calcium. It is not clear which component is critical in the RSM protection mechanism. This study investigated the independent effect of calcium. Ca(2+) was added to lactose solution to examine its influence on the heat resistance of Lactobacillus rhamnosus ZY, Lactobacillus casei Zhang, Lactobacillus plantarum P8 and Streptococcus thermophilus ND03. The results showed that certain Ca(2+) concentrations enhanced the heat resistance of the LAB strains to different extents, that is produced higher survival and shorter regrowth lag times of the bacterial cells. In some cases, the improvements were dramatic. More scientifically insightful and more intensive instrumental study of the Ca(2+) behavior around and in the cells should be carried out in the near future. In the meantime, this work may lead to the development of more cost-effective wall materials with Ca(2+) added as a prime factor. PMID:23617813

  19. Dependence of heat resistance of Drosophila on ambient temperature and relationship of this property to mutation process

    It has been demonstrated that thermosensitvity of the gametes in Drosophila line T correlates with the heat resistance of the flies. This property of the gametes is determined during ontogenesis, depending on the temperature during development and not by genotypic preadaptation as such, i.e., affinity of the females to the heat resistance line T. The ability of females to acquire heat resistance during the adult phase (in the first three days after emergence), i.e., by acclimatization to a temperature different from the temperature during development does not change the response of the gametes to extreme temperature which had developed during ontogenesis under a particular temperature

  20. High-strength Ag-alloyed structural underdensity Al-Cu-Li-Mg alloy

    Mechanical properties under static and dynamic loads, fatigue characteristics, viscosity cleavage, heat resistance, corrosion resistance, physical and thermophysical properties of the pressed underdensity alloy V-1469 have been studied. The alloy corresponds as aluminium deformed high-strength thermally strengthened alloy on the basis of the Al-Cu-Li-Mg system extra alloyed by Ag, Zr, Sc. Comparison of properties of V-1469T1, V95ochT2 and V96ts3-pchT12 alloys pressed flat is conducted

  1. On the metallurgical and environmental factors affecting creep behaviour of hastelloy-x

    Deformation and rupture processes of Hastelloy-X and its modified version in different environment including air, the simulated HTR helium and high vacuum were compared. All the environments showed the effects different from each other. The high vacuum condition caused best reproducible creep and rupture behaviour, and essentially no size effect was involved. While the others caused considerable surface-to-volume ratio effect, and the simulated HTR helium environment showed characteristic effects. The latters were interpleted as the results of the depletion of chromium and molybdenum due respectively to the selective oxidation of the active elements and carburization to enhance the formation of M6C to eventually cause recrystallization of the austenite matrix. (author)

  2. Helium blistering of ceramic coatings on Hastelloy X and Nb--1% Zr

    The surface damage of insulating ceramic coatings on Hastelloy X and Nb--1 percent Zr held at room temperature and at 3000C has been studied for both 100- and 250-keV helium ion irradiation for a dose range from 3.7 x 1018 to 1 x 1019 ions cm-2. Blisters were observed after room temperature irradiation with both 100- and 250-keV helium ions. However, for irradiation at 3000C no blisters could be observed. The sharp rise in the helium permeation with temperature, observed by others for some glasses and ceramics, is thought to be responsible for this behavior. These results suggest that for the energy range studied, helium blistering has a negligible surface erosion effect on such coatings if they are operated at temperatures above 3000C

  3. Operating experience with the heat-resistant material 15 NiCuMoNb 5 in conventional power plants

    Adamsky, F.J.; Teichmann, H.; Tolksdorf, E.

    1998-07-01

    The forerunners of the material 15 NiCuMoNb 5 (WB 36), known as CuNi steels for boiler drums, allowed operating pressures to exceed 100 bar for the first time in the 30s, thereby creating the basis for power station to achieve high performance and efficiency levels. Even present day steel developments for the thick walled components used in nuclear technology have almost reached the level of this steel with regard to the high temperature limit of elasticity as a design value up to temperatures of 400 C, but have not exceeded it. In the mid-60s, extensive investigations were carried out into these materials following a few spectacular cases of serious damage, basically manifesting themselves in two ways: as cracks in the area of the downpipe bores and brittle fractures revealed by pressure testing. The cracks were recognized as stress/strain-induced corrosion and this was counteracted internally by improving the quality of the water, particularly with regard to its oxygen content. The inadequate toughness characteristics, responsible for the fractures occurring during the pressure test, were improved by specific alloying measures and in particular by reducing the sulphur content. Particular attention was paid to welding work. Reporting on operating experience means reporting the results of investigations into damage to components made from heat-resistant materials and providing a critical evaluation. A few examples are summarized below for this purpose. Some are current examples and others go back a few years, but are still the subject of discussion in the sector because of the fundamental knowledge to be gained from them.

  4. Welding consumables for mechanized welding of heat-resistant steel pipelines

    A study was made on properties of welding joints of 15Kh1M1F steel produced under the flux AN-43 in combination with Sv-08KhGSMFA and Sv-08KhMFA wires, as well as under the flux ANK-47 in combination with Sv-08KhMFA wire. It was established that AN-43 flux with Sv-08KhGSMFA wire provided for higher level of mechanical properties and long-term strength and could be recommended for automatic welding of heat resisting steels of 15Kh1M1F type

  5. Transparent Heat-Resistant PMMA Copolymers for Packing Light-Emitting Diode Materials

    Shu-Ling Yeh

    2015-07-01

    Full Text Available Transparent and heat-resistant poly(methyl methacrylate copolymers were synthesized by bulk polymerizing methyl methacrylate (MMA, isobornyl methacrylate (IBMA, and methacrylamide (MAA monomers. Copolymerization was performed using a chain transfer agent to investigate the molecular weight changes of these copolymers, which exhibited advantages including a low molecular weight distribution, excellent optical properties, high transparency, high glass transition temperature, low moisture absorption, and pellets that can be readily mass produced by using extrusion or jet injection for packing light-emitting diode materials.

  6. Assessment of molybdenum influence on long-term heat resistance of selected austenitic steel grades

    Analysis gave evidence that an increase in the long-term heat resistance by addition of approximately 2.5% molybdenum is, in the long run, more efficient in unstabilized austenitic CrNiMo(N) steels of the AISI 316 type than in stabilized X 6 CrNiMoTi 17 12 steel. The effect of molybdenum can be intensified or reduced by factors such as the stabilization ratio and grain size in stabilized CrNiMoTi steels, and the boron, nitrogen and carbon contents in unstabilized CrNiMo(N) steels. (Z.S.). 6 tabs., 6 figs., 62 refs

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

    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.

  8. A possibility of enhancing Jc in MgB2 film grown on metallic hastelloy tape with the use of SiC buffer layer

    We have grown MgB2 on SiC buffer layer by using metallic Hastelloy tape as the substrate. Hastelloy tape was chosen for its potential practical applications, mainly in the power cable industry. SiC buffer layers were deposited on Hastelloy tapes at 400, 500, and 600 degrees C by using a pulsed laser deposition method, and then by using a hybrid physical-chemical vapor deposition technique, MgB2 films were grown on the three different SiC buffer layers. An enhancement of critical current density values were noticed in the MgB2 films on SiC/Hastelloy deposited at 500 and 600 degrees C. From the surface analysis, smaller and denser grains of MgB2 tapes are likely to cause this enhancement. This result infers that the addition of SiC buffer layers may contribute to the improvement of superconducting properties of MgB2 tapes.

  9. Materials for Advanced Turbine Engines (MATE): Project 3: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner, volume 1

    Henricks, R. J.; Sheffler, K. D.

    1984-01-01

    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Incoloy MA 956 (FeCrAl base) and Haynes Developmental Alloy (HDA) 8077 (NiCrAl base) were evaluated. Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. Both alloys demonstrated a +167C (300 F) advantage of creep and oxidation resistance with no improvement in thermal fatigue capability compared to a current generation combustor alloy (Hastelloy X). MA956 alloy was selected for further demonstration because it exhibited better manufacturing reproducibility than HDA8077. Additional property tests were conducted on MA956. To accommodate the limited thermal fatigue capability of ODS alloys, two segmented, mechanically attached, low strain ODS combustor design concepts having predicted fatigue lives or = 10,000 engine cycles were identified. One of these was a relatively conventional louvered geometry, while the other involved a transpiration cooled configuration. A series of 10,000 cycle combustor rig tests on subscale MA956 and Hastelloy X combustor components showed no cracking, thereby confirming the beneficial effect of the segmented design on thermal fatigue capability. These tests also confirmed the superior oxidation and thermal distortion resistance of the ODS alloy. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components was designed and constructed.

  10. Development of heat resistant SiC fibers by radiation curing

    For the structural members for advanced big projects, such as space shuttles, high temperature gas turbines, nuclear fusion and so on, high strength, high reliability and environment durability are required for the materials. In the case of space ships, also light weight is required. As the material suitable to these requirements, fiber-reinforced ceramic composites (CMC) attract most expectation and attention. In order to overcome the brittleness of new ceramics, CMC has been developed. As the reinforcing fibers which are mainly used for CMC, there are silicon carbide fibers. They are light weight, and have high strength, high modulus of elasticity and excellent heat resistance and oxidation resistance. In this report, 'Nicalon' of which the practical use is most advanced among SiC fibers and its application to ceramic composites are described. Also 'Hi-Nicalon' of which the heat resistance was further improved by utilizing radiation is introduced. The manufacturing method of SiC fibers 'Nicalon' and their characteristics, the application of Nicalon fibers, Nicalon-reinforced ceramic composites like CERASEP and Nicaloceram, and the development of Hi-Nicalon are reported. (K.I.)

  11. Enhanced microwave absorbing properties and heat resistance of carbonyl iron by electroless plating Co

    Co coated carbonyl iron particles (Co (CI)) are fabricated through electroless plating method, and the electromagnetic microwave absorbing properties are investigated in the frequencies during 8.2–12.4 GHz. The complex permittivity of CI particles after electroless plating Co is higher than that of raw CI particles due to improvment of the polarization process. Furthermore, according to the XRD and TG results, the Co layer can enhance the heat resistance of CI particles. The bandwidth below −10 dB can reach 3.9 GHz for the Co(CI) absorbent. The results indicate that the electroless plating Co not only enhances the absorbing properties but also improves the heat resistance of CI. - Highlights: • The Co-coated carbonyl iron Co(CI) particles were prepared by electroless plating. • The electromagnetic wave absorbing properties of Co(CI) particles were studied. • The heat treatment on the absorbing property of Co(CI) particles was studied. • The Co(CI) particles have good absorbing property when compared with CI

  12. Study on Curing Kinetics of Heat-resistant Flexible Polyamide Modified Epoxy Resin Adhesive

    Hua Li

    2015-04-01

    Full Text Available In order to study the effects of numerous variables affecting the reaction rate of heat-resistant flexible modified epoxy resin adhesive, the curing kinetics of polyamide modified epoxy resin was studied. The heat-resistant flexible modified epoxy resin adhesive cured at room-temperature was prepared with epoxy resin, polysulfide rubber and organosilicone as adhesive component, polyamide as main curing agent and addition of different modified filler and the curing agent containing benzene ring structure. The curing kinetics of polyamide modified epoxy resin was studied by Differential Scanning Calorimetry (DSC at different heating speeds and the characteristic temperatures of the curing process were analyzed and confirmed. the kinetics parameters of activation energy was calculated using Flynn-Wall-Ozawa equation and Kissinger equation, respectively, then the kinetic model of curing reaction was built as d&alpha/dt = 4.38107 exp (-57740/RT (1-&alpha0.93, the results show that the two-parameter model is adequate to represent the curing reaction process, the model can well describe the curing reaction process of the studied resin. The DSC curves obtained using the experimental data show a good agreement with that theoretically calculated. The research results will provide theoretical basis for the choice of manufacturing process and the optimization of processing window.

  13. Heat resistance of ascospores of Byssochlamys nivea in milk and cream.

    Engel, G; Teuber, M

    1991-02-01

    Byssochlamys nivea strains of rather varying origin used for heat inactivation experiments were cultured for 28 days at 30 degrees C on malt extract agar, since under these conditions the highest degree of heat resistance of the ascospores was observed. Inactivation was performed in steel capillary tubes to obtain reproducible results under experimental conditions comparable to those prevailing in practice. An inactivation temperature of 92 degrees C proved to be most practical. Decimal reduction times for the individual strains at this temperature in Ringer's solution varied between 1.3 and 2.4 s. In the temperature range studied, inactivation of ascospores in UHT milk (1.5% w/w fat content) and cream (10% w/w fat content) has not been found to differ significantly from that in Ringer's solution. Homogenization of milk as applied in practice did not affect heat inactivation of ascospores. Assuming the most unfavorable conditions (50 ascospores/l and using the most heat-resistant strain) the following relations between the level of infected 500 g packages were calculated: 1 of 10(6) packs infected; 24 s at 92 degrees C; 1 of 10(3) packs infected; 16.5 s at 92 degrees C; 1 of 10(2) packs infected, 14 s at 92 degrees C. PMID:2049287

  14. Effect of heating rate on highly heat-resistant spore-forming microorganisms.

    Gómez-Jódar, Isabel; Ros-Chumillas, María; Palop, Alfredo

    2016-03-01

    Highly heat-resistant spore-forming Bacillus cause nonsterility problems in canned food and reduce the shelf life of many processed foods. The aim of this research was to evaluate the thermal inactivation of Bacillus sporothermodurans IIC65, Bacillus subtilis IC9, and Geobacillus stearothermophilus T26 under isothermal and nonisothermal conditions. The data obtained showed that B. sporothermodurans and B. subtilis were more heat resistant than G. stearothermophilus. The survival curves of B. sporothermodurans and B. subtilis showed shoulders, while the survival curves of G. stearothermophilus showed tails. Under nonisothermal treatment, at heating rates of 1 and 20 ℃/min, time needed to completely inactivate G. stearothermophilus was shorter than that required for B. sporothermodurans and B. subtilis. In complex heat treatments (heating-holding-cooling), the survival curves of B. sporothermodurans and B. subtilis showed the same activation shoulders than those obtained under isothermal treatments and the activation shoulders were again absent in the case of G. stearothermophilus. Predictions fitted quite well the data obtained for B. sporothermodurans. In contrast, the data for B. subtilis showed half a log cycle more survival than expected and in the case of G. stearothermophilus, the survival curve obtained showed much higher inactivation than expected. PMID:25852134

  15. Effect that radiation exerts to insulation breakdown of heat resistant polymer materials

    Artificial satellites are always exposed to cosmic rays which contain the radiations which do not reach the ground, therefore, the radiation resistance of the polymer insulators for cables and others used in such environment becomes a problem. Also the polymer insulator materials used for nuclear facilities require excellent radiation resistance. It is important to examine the effect that radiation exerts to electric insulation characteristics from the viewpoint of material development. In this paper, the insulation breakdown characteristics of heat resistant polymer films and the mini-cables made for trial of heat resistant polymer materials in the case without irradiation and in the case of gamma ray irradiation, and the results of the structural analysis are reported. The specimens tested, the experimental method and the results are described. The insulation breakdown strength of PFA and FEP films lowered from 0.15-0.2 MGy, but that of PEEK film did not change up to 5 MGy. It was found that fluorine group resins were apt to deteriorate by oxidation as dose increased. (K.I.)

  16. The heat resistance of a polyurethane coating filled with modified nano-CaCO3

    Li, Bin; Li, Song-Mei; Liu, Jian-Hua; Yu, Mei

    2014-10-01

    The modification of polyurethane coating by adding surface-modified CaCO3 nanoparticles (nano-CaCO3) was investigated in this paper. To improve interfacial interaction between the nano-CaCO3 and the polyurethane (PU) matrix, a silane coupling agent (KH560) was used to modify the nano-CaCO3. The grafting of KH560 on the nano-CaCO3 surfaces was characterized by the TEM, FTIR and TGA techniques. The modification of the nano-CaCO3 surfaces with KH560 was demonstrated to improve the dispersity of nano-CaCO3. FTIR, SEM and AFM were used to characterize the polyurethane coating. The FTIR spectrum indicated that the modification of nano-CaCO3 does not influence the chemical structure of the PU matrix. The roughness and gloss of the nanocomposite coatings containing various amount of nano-CaCO3 were evaluated using a roughness tester and a brightness meter. The heat resistance of the polyurethane coating containing various amounts of nano-CaCO3 was evaluated using the TGA technique. The results revealed that nano-CaCO3 treatment with KH560 improves the nanoparticle dispersion and heat-resistance of polyurethane coating.

  17. Effect of pH on Thermoanaerobacterium thermosaccharolyticum DSM 571 growth, spore heat resistance and recovery.

    Mtimet, Narjes; Guégan, Stéphanie; Durand, Lucile; Mathot, Anne-Gabrielle; Venaille, Laurent; Leguérinel, Ivan; Coroller, Louis; Couvert, Olivier

    2016-05-01

    Thermophilic spore-forming bacteria are potential contaminants in several industrial sectors involving high temperatures (40-65 °C) in the manufacturing process. Among those thermophilic spore-forming bacteria, Thermoanaerobacterium thermosaccharolyticum, called "the swelling canned food spoiler", has generated interest over the last decade in the food sector. The aim of this study was to investigate and to model pH effect on growth, heat resistance and recovery abilities after a heat-treatment of T. thermosaccharolyticum DSM 571. Growth and sporulation were conducted on reinforced clostridium media and liver broth respectively. The highest spore heat resistances and the greatest recovery ability after a heat-treatment were obtained at pH condition allowing maximal growth rate. Growth and sporulation boundaries were estimated, then models using growth limits as main parameters were extended to describe and quantify the effect of pH on recovery of injured spores after a heat-treatment. So, cardinal values were used as a single set of parameters to describe growth, sporulation and recovery abilities. Besides, this work suggests that T. thermosaccharolyticum preserve its ability for germination and outgrowth after a heat-treatment at a low pH where other high resistant spore-forming bacteria like Geobacillus stearothermophilus are unable to grow. PMID:26742617

  18. The effects of radiation on aluminium alloys in the core of energy nuclear reactors

    One of the attractive directions in the worldwide practice of nuclear installations is the replacement of expensive zirconium alloy with more cheap materials, particularly aluminium allo. For Heat Supply Nuclear Plants (HSNP) with approximately 473 K core temperatures, the use of heat-resistant aluminium alloys seems to be reasonable. The present work is concerned with the studies on radiation effects on aluminium alloy, and interaction between the alloy and coolant in the reactor core. (author). 2 refs., 3 figs., 1 tab

  19. Carbon effect on the properties of granular alloy type EhP962P

    The optimum chemical composition of the alloy type EhP962P has been determined. It has been shown that carbon content increase up to 0.12% along with additional alloying to preserve needed quantity of gamma-phase makes it possible to enhance the strength without deterioration of heat resistance

  20. Corrosion behavior of Hastelloy C4 in a MgCl2 rich brine under gamma irradiation

    Corrosion studies performed until now on a number of materials in salt brines have shown that besides the unalloyed steels and Ti 99.8-Pd, also Hastelloy C4 is a promising material for HLW packagings serving as a barrier in a rock salt repository. In order to characterize the corrosion behavior of Hastelloy C4 in more detail, additional corrosion studies under gamma-irradiation were performed. The corrosion medium was a salt brine (Q-brine) rich in MgCl2 which is relevant for accident scenarios in a repository. The test temperature was 90 degree C, the applied dose rates 1 Gy/h, 10 Gy/h and 100 Gy/h and the testing time 1 year at the maximum. The corrosion studies revealed that Hastelloy C4 is susceptible to local corrosion at gamma-dose rates higher than 1 Gy/h. This means that if this material is used for HLW packagings an adequate gamma-shielding will be required

  1. Influencia de los parámetros de soldeo fuerte en la microestructura y propiedades mecánicas de la unión de la aleación base níquel Hastelloy B2

    Sotelo, José Carlos

    2014-09-01

    Full Text Available A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes.Se realizó un estudio pormenorizado del proceso de soldeo fuerte en horno de alto vacío de la aleación base níquel Hastelloy B2 fortalecida por solución sólida. En una primera fase del trabajo se seleccionó el material de aporte acorde al material objeto de unión y a la fuente de calentamiento seleccionada. Posteriormente, se evaluó la influencia del gap (50 y 200 micrómetros y tiempo de permanencia a temperatura de soldeo (10 y 90 minutos sobre los microconstituyentes de la unión, relacionando la microestructura con las propiedades mecánicas de la junta. Los análisis metalográficos mostraron una unión constituida por una matriz rica en níquel, siliciuros de níquel y compuestos ternarios. Finalmente, los resultados de los ensayos mecánicos a esfuerzos cortantes mostraron una elevada resistencia para gaps de 50 micrómetros y tiempos de permanencia de 90 minutos.

  2. Precipitation behavior of Fe2Nb Laves phase on grain boundaries in austenitic heat resistant steels

    Present paper describes the microstructures of Fe–20Cr–30Ni–2Nb (at%) alloys with and without the addition of 0.03%B after aging. Microstructure was investigated using XRD, SEM, EPMA and TEM. Particular attention was paid to Fe2Nb Laves phase present on grain boundaries that may improve creep resistance of this alloy. Furthermore, effects of Boron on precipitation of Fe2Nb Laves phase on grain boundaries were also explored. Precipitates of Laves phase on grain boundaries in the Boron doped alloy were finer and higher in number density than those in the base alloy. Grain boundary segregation of Boron in the alloy was observed, which probably promotes precipitation of Laves phase on grain boundaries, and thereby enhances the creep resistance of the alloy

  3. High-temperature gas-cooled reactor helium compatibility studies: results of 10,000-hour exposure of selected alloys in simulated reactor helium

    Work on the HTGR Helium Compatibility Task accomplished during the period March 31, 1977 through September 30, 1979, is documented in this report. Emphasis is on the results and analyses of creep data to 10,000 h and the detailed metallurgical evaluations performed on candidate alloy specimens tested for up to 10,000 h. Long-term creep and unstressed aging data in controlled-impurity helium and in air at 800, 900, and 10000C are reported for alloys included in the program in FY-76, including the wrought solid-solution-strengthened alloys, Hastelloy X, Hastelloy S, RA 333, and HD 556, and the centrifugally cast austenitic alloys, HK 40, Supertherm, Manaurite 36X, Manaurite 36XS, and Manaurite 900

  4. High-temperature gas-cooled reactor helium compatibility studies: results of 10,000-hour exposure of selected alloys in simulated reactor helium

    Lechtenberg, T.A.; Stevenson, R.D.; Johnson, W.R.

    1980-05-01

    Work on the HTGR Helium Compatibility Task accomplished during the period March 31, 1977 through September 30, 1979, is documented in this report. Emphasis is on the results and analyses of creep data to 10,000 h and the detailed metallurgical evaluations performed on candidate alloy specimens tested for up to 10,000 h. Long-term creep and unstressed aging data in controlled-impurity helium and in air at 800, 900, and 1000/sup 0/C are reported for alloys included in the program in FY-76, including the wrought solid-solution-strengthened alloys, Hastelloy X, Hastelloy S, RA 333, and HD 556, and the centrifugally cast austenitic alloys, HK 40, Supertherm, Manaurite 36X, Manaurite 36XS, and Manaurite 900.

  5. Fatigue Performance of TBCs on Hastelloy X Substrate During Cyclic Bending

    Musalek, Radek; Kovarik, Ondrej; Tomek, Libor; Medricky, Jan; Pala, Zdenek; Hausild, Petr; Capek, Jiri; Kolarik, Kamil; Curry, Nicholas; Bjorklund, Stefan

    2015-10-01

    Our previous experiments with low-cost steel substrates confirmed that individual steps of conventional thermal barrier coating (TBC) deposition may influence fatigue properties of the coated samples differently. In the presented study, testing was carried out for TBC samples deposited on industrially more relevant Hastelloy X substrates. Samples were tested after each step of the TBC deposition process: as-received (non-coated), grit-blasted, bond-coated (NiCoCrAlY), and bond-coated + top-coated yttria-stabilized zirconia (YSZ). Conventional atmospheric plasma spraying (APS) was used for deposition of bond coat and top coat. In addition, for one half of the samples, dual-layer bond coat was prepared by combination of high-velocity air-fuel (HVAF) and APS processes. Samples were tested in the as-sprayed condition and after 100 hours annealing at 980 C, which simulated application-relevant in-service conditions. Obtained results showed that each stage of the TBC manufacturing process as well as the simulated in-service heat exposure may significantly influence the fatigue properties of the TBC coated part. HVAF grit-blasting substantially increased the fatigue performance of the uncoated substrates. This beneficial effect was suppressed by deposition of APS bond coat but not by deposition of dual-layer HVAF + APS bond coat. All heat-treated samples showed again enhanced fatigue performance.

  6. Study on microstructure of pulse laser welding on dissimilar materials hastelloy C-276 and 316L

    To estimate the reliability of laser welding components of AP1000 and study the distribution of elements and microstructure of dissimilar weld of Hastelloy C-276 and 316L welded by Nd: YAG pulse laser, the microstructure, element distribution and phase of the weld were systematically analyzed by optical microscope, electron probe x ray micro-analyser and other analysis, measuring and test instruments. The results show that the gain of microstructure of weld is refined, and tiny equiaxed grains are in the center and columnar grains are near the weld edge. Heat-affected zones are very narrow on two sides of the weld joint. According to macro distribution of elements, there are three zones in the weld. Element compositions vary drastically on two sides of the weld and become uniform in the center. Micro-segregation of elements exists and Mo enriched at the grain boundary of the weld is observed. Austenite is the main microstructure of the weld and little delta ferrite is found. (authors)

  7. Fatigue Performance of TBCs on Hastelloy X Substrate During Cyclic Bending

    Musalek, Radek; Kovarik, Ondrej; Tomek, Libor; Medricky, Jan; Pala, Zdenek; Hausild, Petr; Capek, Jiri; Kolarik, Kamil; Curry, Nicholas; Bjorklund, Stefan

    2016-01-01

    Our previous experiments with low-cost steel substrates confirmed that individual steps of conventional thermal barrier coating (TBC) deposition may influence fatigue properties of the coated samples differently. In the presented study, testing was carried out for TBC samples deposited on industrially more relevant Hastelloy X substrates. Samples were tested after each step of the TBC deposition process: as-received (non-coated), grit-blasted, bond-coated (NiCoCrAlY), and bond-coated + top-coated yttria-stabilized zirconia (YSZ). Conventional atmospheric plasma spraying (APS) was used for deposition of bond coat and top coat. In addition, for one half of the samples, dual-layer bond coat was prepared by combination of high-velocity air-fuel (HVAF) and APS processes. Samples were tested in the as-sprayed condition and after 100 hours annealing at 980 °C, which simulated application-relevant in-service conditions. Obtained results showed that each stage of the TBC manufacturing process as well as the simulated in-service heat exposure may significantly influence the fatigue properties of the TBC coated part. HVAF grit-blasting substantially increased the fatigue performance of the uncoated substrates. This beneficial effect was suppressed by deposition of APS bond coat but not by deposition of dual-layer HVAF + APS bond coat. All heat-treated samples showed again enhanced fatigue performance.

  8. Thermal, epithermal and thermalized neutron attenuation properties of ilmenite-serpentine heat resistant concrete shield

    Experimental measurements were carried out to study the attenuation properties of low-energy neutrons transmitted through unheated and preheated barriers of heavy-weight, highly hydrated and heat-resistant concrete shields. The concrete shields under investigation have been prepared from naturally occurring ilmenite and serpentine Egyptian ores. A collimated beam obtained from an Am-Be source was used as a source of neutrons, while the measurements of total thermal, epithermal, and thermalized neutron fluxes were performed using a BF-3 detector, multichannel analyzer and Cd filter. Results show that the ilmenite-serpentine concrete proved to be a better thermal, epithermal and thermalized neutron attenuator than the ordinary concrete especially at a high temperature of concrete exposure. (Author)

  9. Evaluating the effectiveness of heat-resistant cast steel filtration from the results of structure examinations

    Asłanowicz M.

    2007-01-01

    Full Text Available Filtration guarantees castings characterised by high quality and free from any non-metallic inclusions, which are formed at the stage of melting and pouring of liquid metal. This article discusses the problem of the effectiveness of filtration process taking as an example heat-resistant cast steel poured into ceramic moulds. In investigations, foamed zircon filters made by FerroTerm Sp. z o.o. The effectiveness of filtration was described and examined using the results of metallographic examinations, including macro- and micro-structure examinations of metal and of cast metal/ceramic filter interface, and measurements of the content of non-metallic inclusions. The methods of investigations were presented, the obtained results were described, and relevant conclusions were drawn, all of them unmistakably indicating a very beneficial effect that filtration has on molten metal quality. Łódź, Poland, were used.

  10. Improving deformability of stainless and heat resisting two-phase steels in cold or hot rolling

    The effect is studied of the polymorphous α→γ - transformation occurring in the deformation zone under the action of deformation itself, in martensitic-ferritic steels, on the position of the critical brittleness temperature (Tsub(c)). As this transformation develops, the level of Tsub(c) in these steels shifts to the lower-temperature region. The formation of the optimal phase composition in the process of hot plastic deformation itself may be one of the possible ways for enhancing the deformability of two-phase martensitic ferritic steels during the subsequent cold rolling, as well as of austenitic-ferritic steels during hot deformation. Optimal conditions for the proposed technology of high-temperature mechanical treatment as applied to two-phase corrosion and heat-resistant steels have been developed

  11. Adriamycin resistance, heat resistance and radiation response in Chinese hamster fibroblasts

    Previous investigators have demonstrated synergistic interaction between hyperthermia and radiation or Adriamycin (ADR), using cell lines that are sensitive to heat or ADR alone. The authors investigated the effect of heat, radiation or ADR on Chinese hamster fibroblasts (HA-1), their heat resistant variants and their ADR resistant variants. Heat for ADR resistance did not confer cross resistance to radiation. Cells resistant to heat did show cross resistance to ADR. While cells selected for ADR resistance were not cross resistant to heat, they did not exhibit drug potentiation by hyperthermia, characteristic of ADR sensitive cells. Cytofluorometric measurement showed decreased ADR uptake in both heat and ADR resistant cells. The possibility of cross resistance between heat and ADR should be considered when designing combined modality trials

  12. Fire- and heat-resistant laminating resins based on maleimido-substituted aromatic cyclotriphosphazenes

    Kumar, D.; Fohlen, G. M.; Parker, J. A.

    1983-01-01

    A novel class of flame- and heat-resistant polymers has been synthesized by the thermal polymerization of maleimido-substituted aromatic cyclotriphosphazenes. The polymer obtained from tris-(aminophenoxy)tris(maleimidophenoxy)cyclotriphosphazene has good thermal stability and is noteworthy for its high char yield, viz., 82 percent at 800 C in nitrogen and 81 percent at 700 C in air. Graphite-fabric laminates prepared with this polymer did not burn in pure oxygen, even at 300 C, and were tested for mechanical properties. Hexakis(4-maleimidophenoxy)cyclotriphosphazene and some fluorine-containing monomers have also been synthesized. The structures of these cyclic phosphazene precursors and polymers were characterized by FT IR spectrophotometry, H-1 NMR, F-19 NMR, and P-31 solid-state magic angle spinning NMR spectroscopy, and mass spectrometry. The curing behavior of the polymer precursors and the thermal stabilities of the polymers were evaluated by differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA).

  13. Analysis of cyclic plastic response of heat resistant Sanicro 25 steel at ambient and elevated temperatures

    Polák, Jaroslav; Petráš, Roman; Heczko, Milan; Kruml, Tomáš; Chai, G.

    Amsterdam : Elsevier, 2014 - (Gulagliano, M.; Vergani, L.), s. 68-73 ISSN 1877-7058. - (Procedia Engineering. 74). [ICMFM 2014 International Colloquium on Mechanical Fatigue of Metals /17./. Verbania (IT), 25.06.2014-27.06.2014] R&D Projects: GA ČR(CZ) GA13-23652S Institutional support: RVO:68081723 Keywords : heat resistant steel * Sanicro 25 * cyclic plasticity * dislocation structure * effect of temperature Subject RIV: JL - Materials Fatigue, Friction Mechanics http://ac.els-cdn.com/S1877705814007966/1-s2.0-S1877705814007966-main.pdf?_tid=8150a71a-543c-11e4-b10e-00000aab0f27&acdnat=1413358137_888616b4b84bb7ddf28dfaee5358a90a

  14. Water soluble and heat resistant polymers by free radical polymerization of lactic acid-based monomers

    Tanaka, Hitoshi; Kibayashi, Tatsuya; Niwa, Miki

    2013-08-01

    Tactic heat resistant polymer was prepared by free radical polymerization of lactic acid-based monomers, i.e. chiral 2-isopropyl-5-methylene-1,3-dioxolan-4-ones (1). The polymerization of 1 proceeded smoothly without ring-opening to give a polymer with high isotacticity (mm) of 29.7~100% and glass transition temperature (Tg) of 172~213C. 1 also showed high reactivity in the copolymerization with styrene and methyl methacrylate, and the incorporation of 1 unit in the copolymer structure increased Tg of each polymer. In addition, hydrolysis of poly(1) produced a new type of water soluble poly(lactic acid), i.e. poly(?-hydroxy acrylate), and poly(?-hydroxy acrylate-co-divinyl benzene) hydrogel absorbed water as high as 1000 times of the original polymer weight.

  15. Estimating the Condition of the Heat Resistant Lining in an Electrical Reduction Furnace

    Jan G. Waalmann

    1988-01-01

    Full Text Available This paper presents a system for estimating the condition of the heat resistant lining in an electrical reduction furnace for ferrosilicon. The system uses temperature measured with thermocouples placed on the outside of the furnace-pot. These measurements are used together with a mathematical model of the temperature distribution in the lining in a recursive least squares algorithm to estimate the position of 'the transformation front'. The system is part of a monitoring system which is being developed in the AIP-project: 'Condition monitoring of strongly exposed process equipment in thc ferroalloy industry'. The estimator runs on-line, and results arc presented in colour-graphics on a display unit. The goal is to locate the transformation front with an accuracy of +- 5cm.

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

    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

  17. Data on post irradiation experiments of heat resistant ceramic composite materials. PIE for 97M-13A

    Baba, Shin-ichi; Ishihara, Masahiro; Souzawa, Shizuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Sekino, Hajime [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    The research on the radiation damage mechanism of heat resistant ceramic composite materials is one of the research subjects of the innovative basic research in the field of high temperature engineering, using the High Temperature engineering Test Reactor (HTTR). Three series of irradiation tests on the heat resistant ceramic composite materials, first to third irradiation test program, were carried out using the Japan Material Testing Reactor (JMTR). This is a summary report on the first irradiation test program; irradiation induced dimensional change, thermal expansion coefficient, X-ray diffraction and {gamma}-ray spectrum are reported. (author)

  18. Fine section rolling from unyielding alloys

    The rolling of small-size blanks (of diameter up to 16 mm) from unyielding heat-resistant alloys was studied at different temperatures and rates of deformation. Four heat-resistant alloys were chosen: i.e. three ones based on nickel (EI4.37B, EI867VD and EP220VD) and one based on iron (EG33), three stainless steels (Kh18N10T, 1KhB, Kh17N2). The shape variation, power and other parameters of rolling, the quality and properties of the metal were studied. Very high loads in alloy rolling were noted. In the rolling of the EI867BD alloy the pressure is 2.5-3.8 times higher than for Kh18N10T steel under identical conditions. When rolling in the optimum temperature regime, the quality of the metal surface is good. The heat resistance and mechanical properties of the metal of the test batch in a circle of 16 mm diameter exceed the technical requirements

  19. Thermal conductivity, electrical resistivity, and thermopower of aerospace alloys from 4 to 300 K.

    Hust, J. G.; Weitzel, D. H.; Powell, R. L.

    1971-01-01

    Measurement of thermal conductivity, electrical resistivity, and thermopower for several aerospace alloys: titanium alloy A110-AT, aluminum alloy 7039, Inconel 718, and Hastelloy X. Tables and graphs of the measured properties and Lorenz ratio are presented over the range from 4 to 300 K. Comparisons to other measurements and theoretical analysis of the data are included. The uncertainties of the property data are estimated as 0.7 to 2.5% for thermal conductivity, 0.25% in electrical resistivity, and about 0.1 microvolt/K in thermopower.

  20. Creep crack growth behavior of several structural alloys

    Sadananda, K.; Shahinian, P.

    1983-07-01

    Creep crack growth behavior of several high temperature alloys, Inconel 600, Inconel 625, Inconel X-750, Hastelloy X, Nimonic PE-16, Incoloy 800, and Haynes 25 (HS-25) was examined at 540, 650, 760, and 870 °C. Crack growth rates were analyzed in terms of both linear elastic stress intensity factor and J*-integral parameter. Among the alloys Inconel 600 and Hastelloy X did not show any observable crack growth. Instead, they deformed at a rapid rate resulting in severe blunting of the crack tip. The other alloys, Inconel 625, Inconel X-750, Incoloy 800, HS-25, and PE-16 showed crack growth at one or two temperatures and deformed continuously at other temperatures. Crack growth rates of the above alloys in terms ofJ* parameter were compared with the growth rates of other alloys published in the literature. Alloys such as Inconel X-750, Alloy 718, and IN-100 show very high growth rates as a result of their sensitivity to an air environment. Based on detailed fracture surface analysis, it is proposed that creep crack growth occurs by the nucleation and growth of wedge-type cracks at triple point junctions due to grain boundary sliding or by the formation and growth of cavities at the boundaries. Crack growth in the above alloys occurs only in some critical range of strain rates or temperatures. Since the service conditions for these alloys usually fall within this critical range, knowledge and understanding of creep crack growth behavior of the structural alloys are important.

  1. Effect of mixed heat-resistances on the optimal configuration and performance of a heat-engine cycle

    The finite-time thermodynamic performance of a generalized Carnot-cycle, under the condition of mixed heat-resistances, is studied. The optimal configuration and the fundamental optimal relation between power and efficiency of the cycle are derived. The results provide some guidance for the design of practical engines

  2. Corundum Molds for Investment Casting from Refractory Alloys and Metals

    A. S. Murkina; Varfolomeev, M. S.; D.V. Sidorov; Storozhenko, P. A.; G. I. Shcherbakova

    2010-01-01

    Production procedure, physical-chemical, and performance properties of ALUMOX silica-free binder used for the production of high-heat-resistant corundum shell molds by consumable patterns employed in the production of critical molds from superalloyed reactive metals and alloys are described. ALUMOX usage allows obtaining casts from reactive metals and alloys with surface roughness up to 6 0   m), which, in its turn, increases fatigue parameters of the mat...

  3. Feasibility study on potential productivity of heat-resisting and advanced semiconductors by using the HTTR

    Worldwide attention has been paid to GaAs and SiC as a kind of the heat-resisting and advanced semiconductor materials. Doping of specific impurities into semiconductor materials is a key technology for producing semiconductor devices. As one of doping technologies, thermal diffusional doping has been successfully applied to Si. Application of thermal diffusional doping to GaAs needs expensive and complicated processes in order to prevent an occurrence of lattice defects by impurities. On the other hand, it is difficult to apply this technology to SiC, because of small diffusion coefficient of impurities to SiC. Therefore, it is of great importance to develop a substitutional doping technology for these materials for realizing heat-resisting and advanced semiconductor. To dope some impurities into Si crystal by using neutron irradiation is a mature technology and is called NTD. The High Temperature engineering Test Reactor(HTTR) has an unique and superior capability to irradiate large-sized specimen, in the order of 10cm in diameter, at high temperature up to approximately 1000degC. This report presents a result of feasibility study of potential applicability and effectiveness of NTD to GaAs and SiC at the HTTR. First of all, advantages and disadvantages were identified by reviewing the state-of-the-art technology of NTD to Si. Potential applicability of NTD to GaAs and SiC are discussed. Based on this discussion, effectiveness and feasibility of NTD to these materials at the HTTR are examined. As a result, NTD is feasible to SiC but not to GaAs. The HTTR provides the capability to produce SiC semiconductor, in particular, to produce the semiconductor with (1) low irradiation damage, (2) uniform distribution of doped impurities and (3) high productivity, if a large-sized SiC crystal is capable to be commercialized. Practical application of NTD at the HTTR will be discussed in the next study. (author)

  4. Effects of alpha-tocopherol addition to polymeric coatings on the UV and heat resistance of a fibrous collagen material--chrome-free leather

    UV and heat resistance are very important qualities of leather because most leather products are constantly exposed to outdoor environments. In recent years, we have focused on using environmentally friendly antioxidants that will improve the UV and heat resistance of chrome-free leather. Tocopher...

  5. The technology for automated development of economically doped heat-resistant nickel superalloys

    Shmotin Yuriy

    2014-01-01

    Full Text Available The paper presents the usage of computational technology, aimed at automated search for optimum compositions of nickel superalloys, being minimally doped by expensive rhenium and having no ruthenium. Resulting doping compositions ensure ultimate long-term high-temperature strength. The technology is based on computer model of alloy and numerical optimization routine. The model computes relation between an alloy composition and its performance characteristics. Multiobjective optimization procedure provides for an automated search for alloy composition to ensure the set of pre-defined properties of a new material. Two new nickel-based single-crystal superalloys are presented, which were created using this technology. SLGS-3 features high-temperature strength (100 hours at 1,000 degrees Centigrade at approximately 345?MPa. Its composition does not contain ruthenium. SLGS-1 alloy provided for 265?MPa and contained neither rhenium nor ruthenium in its composition.

  6. Polyphasic taxonomy of the heat resistant ascomycete genus Byssochlamys and its Paecilomyces anamorphs.

    Samson, R A; Houbraken, J; Varga, J; Frisvad, J C

    2009-06-01

    Byssochlamys and related Paecilomyces strains are often heat resistant and may produce mycotoxins in contaminated pasteurised foodstuffs. A comparative study of all Byssochlamys species was carried out using a polyphasic approach to find characters that differentiate species and to establish accurate data on potential mycotoxin production by each species. Phylogenetic analysis of the ITS region, parts of the beta-tubulin and calmodulin genes, macro- and micromorphological examinations and analysis of extrolite profiles were applied. Phylogenetic analyses revealed that the genus Byssochlamys includes nine species, five of which form a teleomorph, i.e. B. fulva, B. lagunculariae, B. nivea, B. spectabilis and B. zollerniae, while four are asexual, namely P. brunneolus, P. divaricatus, P. formosus and P. saturatus. Among these, B. nivea produces the mycotoxins patulin and byssochlamic acid and the immunosuppressant mycophenolic acid. Byssochlamys lagunculariae produces byssochlamic acid and mycophenolic acid and thus chemically resembles B. nivea. Some strains of P. saturatus produce patulin and brefeldin A, while B. spectabilis (anamorph P. variotii s.s.) produces viriditoxin. Some micro- and macromorphological characters are valuable for identification purposes, including the shape and size of conidia and ascospores, presence and ornamentation of chlamydospores, growth rates on MEA and CYA and acid production on CREA. A dichotomous key is provided for species identification based on phenotypical characters. PMID:20198134

  7. Growth modelling of heat-resistant fungi: the effect of water activity.

    Valík, L; Piecková, E

    2001-01-22

    Growth of three strains of heat-resistant fungi, Byssochlamys fulva, Neosartorya fischeri and Talaromyces avellaneus, was studied at 25 degrees C at eight or nine water activities (a(w)) adjusted with sucrose between 0.995 and 0.85. The flexible growth model of Baranyi describing the change in colony diameter (mm) with respect to time was first fitted to measured growth data and from the fitted curves the maximum colony growth rates were estimated. These values were fitted with respect to a(w) to predict colony growth rates at any a(w) within the range tested. Optimum a(w) values of 0.986, 0.985, and 0.990 for growth, and maximum colony growth rates of 12.6, 13.2 and 20.2 mm d(-1), respectively, were calculated. The time to reach a colony diameter of 3 mm and the optimum a(w) for each strain were also calculated. The results can be applied to the prevention of spoilage of canned fruit or juices and other heat processed fruit based products. PMID:11205942

  8. Effect of temperature on the physical properties of ilmenite-serpentine heat resistant concrete radiation shields

    A series of experimental studies has been carried out to determine the change in unit weight, compressive strength, water content and neutron macroscopic cross section of a new type of concrete shields made from egyptian limonite and serpentine ores when heated for long period at temperatures up to 600 degree C. Results show that the unit weight of the cure concrete has a value 2.98 Ton/M3 and decreases with increasing temperature, while the compressive strength reaches a maximum value of 19 Ton/M2 at 100 degree C. The differential thermal analysis (D.T.A.)of this concrete shows three endothermic peaks at 100 degree C, 480 degree C. Also, the thermogravimetry analysis (T.G.A.) shows that the cure concrete retains about 11% water content of the total sample weight and still retains 4.5% of its initial value when heated for long period at 600 degree C. Results also show that the neutron macroscopic cross section (for neutrons of energies <1 MeV) of the limonite-serpentine heat resistant concrete decreases to 18.6% of its initial value after heating 600 degree C

  9. Characterization and radiation response of a heat-resistant variant of V79 cells

    A thermoresistant variant of the established cell line V79-S171-W1 was isolated after treatment with nitrosoguanidine and repeated heat treatments at 42.6 to 430C, and showed an enhanced ability to survive at 42.6, 43.5, and44.50C. The rates of inactivation of the normal and heat-resistant lines differed by approximately a factor of 2 over this temperature range. This level of thermoresistance was stable for the first 80 doublings, but was lost by 120 doublings. This may have been due to a reversion to the normal V79 line since there was no continuous selection pressure and the thermoresistant variant, which was designated at HR7, had a longer average doubling time. Transient thermotolerance was induced in both the V79 and HR7 cells by a 10-min expsure to 44.50C. After 3 hr incubation at 370C, both cell lines had an identical sensitivity to further exposure to 44.50C. Thus the long-term thermoresistance of the HR7 cells may be due to a permanent induction of a low level of thermotolerance. The (ionizing) radiation survival curves and the ability to repair sublethal radiation damage were identical for the thermoresistance variant and the parent cell line

  10. Spatial fluxes and energy distributions of reactor fast neutrons in two types of heat resistant concretes

    Measurements have been carried out to study the spatial fluxes and energy distributions of reactor fast neutrons transmitted through two types of heat resistant concretes, serpentine concrete and magnetic lemonite concrete. The physical, chemical and mechanical properties of these concretes were checked by well known techniques. In addition, the effect of heating at temperatures up to 500deg C on the crystaline water content was checked by the method of differential thermal analysis. Measurements were performed using a collimated beam of reactor neutrons emitted from a 10 MW research reactor. The neutron spectra transmitted through concrete barriers of different thickness were measured by a scintillation spectrometer with NE-213 liquid organic scintillator. Discrimination against undesired pulses due to gamma-rays was achieved by a method based on pulse shape discrimination technique. The operating principle of this technique is based on the comparison of two weighted time integrals of the detector signal. The measured pulse amplitude distribution was converted to neutron energy distribution by a computational code based on double differentiation technique. The spectrometer workability and the accuracy of the unfolding technique were checked by measuring the neutron spectra of neutrons from Pu-α-Be and 252Cf neutron sources. The obtained neutron spectra for the two concretes were used to derive the total cross sections for neutrons of different energies. (orig.)

  11. Creep deformation characterization of heat resistant steel by stress change test

    To evaluate the creep deformation mechanism of heat resistant steel, stress change tests were conducted during creep tests for Modified 9Cr-1Mo Steel and 2.25Cr-1Mo Steel. In this study it was confirmed that the dislocation behavior during the creep tests was in viscous manner because of no instantaneous plastic strain observed at stress increments. Transient backward creep behavior was observed after stress reduction for these steels in this work. Mobilities of dislocation were evaluated by observed backward creep behavior after stress reductions. Internal stresses were evaluated by the changes of creep rate in stress increments. And mobile dislocation densities were evaluated with the estimated mobilities of dislocation and the changes of creep rate in stress increments. It was found that the variation of evaluated mobile dislocation densities during creep deformation showed the same tendency as the variation of creep rate. Therefore mobile dislocation density is the dominant factor that influences the creep rate variation in creep deformation of these steels in this work. The mobilities of dislocation showed a good correlation with 1/T and related with solute amount of Mo that is a solution hardening element.

  12. Creep deformation characterization of heat resistant steel by stress change test

    Hayakawa, Hiroyuki [Environment Department, Kyudensangyo Co., Inc., 2-18-20, Najima, Higashi-ku, Fukuoka 813-0043 (Japan)], E-mail: hiroyuki_hayakawa@kyudensangyo.co.jp; Nakashima, Satoshi [Environment Department, Kyudensangyo Co., Inc., 2-18-20, Najima, Higashi-ku, Fukuoka 813-0043 (Japan); Kusumoto, Junichi; Kanaya, Akihiro [Research Laboratory, Kyushu Electric Power Co., Inc., 2-1-47, Shiobaru, Minami-ku, Fukuoka 815-8520 (Japan); Nakashima, Hideharu [Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakouen, Kasuga-City, Fukuoka 816-8580 (Japan)

    2009-09-15

    To evaluate the creep deformation mechanism of heat resistant steel, stress change tests were conducted during creep tests for Modified 9Cr-1Mo Steel and 2.25Cr-1Mo Steel. In this study it was confirmed that the dislocation behavior during the creep tests was in viscous manner because of no instantaneous plastic strain observed at stress increments. Transient backward creep behavior was observed after stress reduction for these steels in this work. Mobilities of dislocation were evaluated by observed backward creep behavior after stress reductions. Internal stresses were evaluated by the changes of creep rate in stress increments. And mobile dislocation densities were evaluated with the estimated mobilities of dislocation and the changes of creep rate in stress increments. It was found that the variation of evaluated mobile dislocation densities during creep deformation showed the same tendency as the variation of creep rate. Therefore mobile dislocation density is the dominant factor that influences the creep rate variation in creep deformation of these steels in this work. The mobilities of dislocation showed a good correlation with 1/T and related with solute amount of Mo that is a solution hardening element.

  13. Microstructure and texture evolution of CeO2 buffer layers prepared via dip-coating sol-gel method on IBAD-YSZ/Hastelloy substrates

    We have fabricated CeO2 buffer layers on IBAD-YSZ/Hastelloy substrates via dip-coating sol-gel method using inorganic salts as starting materials. X-ray diffraction (XRD), scanning electron microscopy (SEM) and scanning probe microscope (SPM) were applied to investigate the influential factors in film formation and texture evolution. Flat, crack-free CeO2 films with sharp (0 0 2) c-axis orientation and good texture were obtained by carefully controlling the precursor solution quality, dip-coating and heating process. Compared with IBAD-YSZ/Hastelloy substrates, textures of CeO2 films were effectively improved

  14. Microstructure and texture evolution of CeO{sub 2} buffer layers prepared via dip-coating sol-gel method on IBAD-YSZ/Hastelloy substrates

    Du, P. [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China)], E-mail: honey00@mails.tsinghua.edu.cn; Wang, S.S.; Chen, H.; Wang, Z.; Sun, J.C.; Han, Z. [Applied Superconductivity Research Center, Department of Physics, Tsinghua University, Beijing 100084 (China); Schmidt, W.; Neumuller, H.W. [Siemens AG, CT PS 3, Erlangen 91052 (Germany)

    2007-10-01

    We have fabricated CeO{sub 2} buffer layers on IBAD-YSZ/Hastelloy substrates via dip-coating sol-gel method using inorganic salts as starting materials. X-ray diffraction (XRD), scanning electron microscopy (SEM) and scanning probe microscope (SPM) were applied to investigate the influential factors in film formation and texture evolution. Flat, crack-free CeO{sub 2} films with sharp (0 0 2) c-axis orientation and good texture were obtained by carefully controlling the precursor solution quality, dip-coating and heating process. Compared with IBAD-YSZ/Hastelloy substrates, textures of CeO{sub 2} films were effectively improved.

  15. Extreme Heat Resistance of Food Borne Pathogens Campylobacter jejuni, Escherichia coli, and Salmonella typhimurium on Chicken Breast Fillet during Cooking.

    de Jong, Aarieke E I; van Asselt, Esther D; Zwietering, Marcel H; Nauta, Maarten J; de Jonge, Rob

    2012-01-01

    The aim of this research was to determine the decimal reduction times of bacteria present on chicken fillet in boiling water. The experiments were conducted with Campylobacter jejuni, Salmonella, and Escherichia coli. Whole chicken breast fillets were inoculated with the pathogens, stored overnight (4C), and subsequently cooked. The surface temperature reached 70C within 30?sec and 85C within one minute. Extremely high decimal reduction times of 1.90, 1.97, and 2.20?min were obtained for C. jejuni, E. coli, and S. typhimurium, respectively. Chicken meat and refrigerated storage before cooking enlarged the heat resistance of the food borne pathogens. Additionally, a high challenge temperature or fast heating rate contributed to the level of heat resistance. The data were used to assess the probability of illness (campylobacteriosis) due to consumption of chicken fillet as a function of cooking time. The data revealed that cooking time may be far more critical than previously assumed. PMID:22389647

  16. Efficacy of Traditional Almond Decontamination Treatments and Electron Beam Irradiation against Heat-Resistant Salmonella Strains.

    Cuervo, Mary P; Lucia, Lisa M; Castillo, Alejandro

    2016-03-01

    Two outbreaks of salmonellosis were linked to the consumption of raw almonds from California in 2001 and 2004. As a result, federal regulations were developed, which mandate that all almonds grown in California must be treated with a process that results in a 4-log reduction of Salmonella. Because most of the technologies approved to treat almonds rely on the application of heat to control Salmonella, an evaluation of alternative technologies for inactivating heat-resistant Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W was needed. In this study, almonds were inoculated with Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W and then treated with an electron beam (e-beam) or by blanching or oil roasting. The irradiation D10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W treated with e-beam were 0.90 and 0.72 kGy, respectively. For heat treatments, thermal D10-values for Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W strains were 15.6 and 12.4 s, respectively, when subjected to blanching at 88°C and 13.2 and 10.9 s, respectively, when roasted in oil at 127 ± 2°C. No significant differences in irradiation and thermal treatment results were observed between Salmonella Enteritidis PT30 and Salmonella Senftenberg 775W (P > 0.05), indicating that e-beam irradiation may be a feasible technology for reducing Salmonella in almonds. However, the sensory changes resulting from irradiating at the doses used in this study must be evaluated before e-beam irradiation can be used as a nonthermal alternative for decontamination of almonds. PMID:26939646

  17. Study of the influence of sporulation conditions on heat resistance of Geobacillus stearothermophilus used in the development of biological indicators for steam sterilization.

    Guizelini, Belquis P; Vandenberghe, Luciana P S; Sella, Sandra Regina B R; Soccol, Carlos Ricardo

    2012-12-01

    Biological indicators are important tools in infection control via sterilization process monitoring. The use of a standardized spore crop with a well-defined heat resistance will guarantee the quality of a biological indicator. Ambient factors during sporulation can affect spore characteristics and properties, including heat resistance. The aim of this study is to evaluate the main sporulation factors responsible for heat resistance in Geobacillus stearothermophilus, a useful biological indicator for steam sterilization. A sequence of a three-step optimization of variables (initial pH, nutrient concentration, tryptone, peptone, beef extract, yeast extract, manganese sulfate, magnesium sulfate, calcium chloride and potassium phosphate) was carried out to screen those that have a significant influence on heat resistance of produced spores. The variable exerting greatest influence on G. stearothermophilus heat resistance during sporulation was found to be the initial pH. Lower nutrient concentration and alkaline pH around 8.5 tended to enhance decimal reduction time at 121 °C (D(121°C)). A central composite design enabled a fourfold enhancement in heat resistance, and the model obtained accurately describes positive pH and negative manganese sulfate concentration influence on spore heat resistance. PMID:22872104

  18. Neutralizing activity of monoclonal antibodies to heat-sensitive and heat-resistant epitopes of Rickettsia rickettsii surface proteins.

    Anacker, R L; McDonald, G A; List, R. H.; Mann, R E

    1987-01-01

    Antiprotein monoclonal antibodies derived from mice inoculated with Rickettsia rickettsii heated at 56 degrees C for 15 min are of two types: one is type specific for epitopes denatured by moderate temperatures, and the other is specific for epitopes resistant to 100 degrees C for 5 min. The heat-resistant epitopes are found by immunoblotting on multiple polypeptides after solubilization of the rickettsiae at temperatures of 56 degrees C or higher. Most, but not all, antibodies to the heat-se...

  19. Sustainable, heat-resistant and flame-retardant cellulose-based composite separator for high-performance lithium ion battery

    Jianjun Zhang; Liping Yue; Qingshan Kong; Zhihong Liu; Xinhong Zhou; Chuanjian Zhang; Quan Xu; Bo Zhang; Guoliang Ding; Bingsheng Qin; Yulong Duan; Qingfu Wang; Jianhua Yao; Guanglei Cui; Liquan Chen

    2014-01-01

    A sustainable, heat-resistant and flame-retardant cellulose-based composite nonwoven has been successfully fabricated and explored its potential application for promising separator of high-performance lithium ion battery. It was demonstrated that this flame-retardant cellulose-based composite separator possessed good flame retardancy, superior heat tolerance and proper mechanical strength. As compared to the commercialized polypropylene (PP) separator, such composite separator presented impro...

  20. Molecular epidemiology and heat resistance of Listeria monocytogenes in meat products and meat-processing plants and listeriosis in Latvia

    Berzins, Aivars

    2010-01-01

    The prevalence, contamination and heat resistance of Listeria monocytogenes were investigated in meat products and meat-processing plants. Moreover, trends of human listeriosis in Latvia were studied over a 10-year period from 1998 to 2007. A high prevalence (40%) of L. monocytogenes was found in cold-smoked meat products compared with other heat-treated ready-to-eat meat products (0.7%) available in retail markets in Latvia. Pulsed-field gel electrophoresis (PFGE) and serotyping were ap...

  1. Electromagnetic property of SiO{sub 2}-coated carbonyl iron/polyimide composites as heat resistant microwave absorbing materials

    Wang, Hongyu, E-mail: wanghongyu07010310@163.com; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-02-01

    Heat resistant microwave absorbing materials were prepared by compression molding method, using polyimide resin as matrix and SiO{sub 2} coated carbonyl iron (CI) as filler. The SiO{sub 2} coated CI particles were prepared by Stober process. The microwave absorbing properties and the effect of heat treatment on the electromagnetic properties of SiO{sub 2} coated CI/polyimide composites were investigated. When the content of SiO{sub 2} coated CI is 60 wt%, the value of minimum reflection loss decreases from ?25 dB to ?33 dB with the thickness increases from 1.5 mm to 2.1 mm. According to the thermal-gravimetric analyses (TGA) curves, the polyimide matrix can be used at 300 C for long time. The complex permittivity of the composites slightly increases while the complex permeability almost keeps constant after heat treatment at 300 C for 10 h, which indicating that the composites can be used at elevated temperature as microwave absorbing materials at the same time have good heat resistance and microwave absorption. - Highlights: Polyimide as matrix and SiO{sub 2} coated carbonyl iron as filler. The SiO{sub 2} coated CI shows good absorbing properties. The composites have good heat resistance.

  2. Identification and characterization of a heat-resistant protease from Serratia liquefaciens isolated from Brazilian cold raw milk.

    Machado, Solimar Gonçalves; Heyndrickx, Marc; De Block, Jan; Devreese, Bart; Vandenberghe, Isabel; Vanetti, Maria Cristina Dantas; Van Coillie, Els

    2016-04-01

    The cold storage of raw milk before heat treatment in dairy industry promotes the growth of psychrotrophic microorganisms, which are known for their ability to produce heat-resistant proteolytic enzymes. Although Pseudomonas is described as the main causative genus for high proteolytic spoilage potential in dairy products, Serratia liquefaciens secretes proteases and may be found in raw milk samples as well. However, at the present there is no information about the proteolytic spoilage potential of S. liquefaciens in milk after heat-treatment. The main aim of this research was to assess the proteolytic spoilage potential of S. liquefaciens isolated from Brazilian raw milk and to characterize the involved protease. S. liquefaciens was shown to secrete one heat-resistant spoilage metalloprotease of, approximately, 52kDa encoded by the ser2 gene. The heat-resistance of Ser2 was similar to the aprX encoded metalloprotease produced by Pseudomonas. Although the ser2 gene was detected in all S. liquefaciens isolates tested in this study, the proteolytic activity of the isolates in milk was highly heterogeneous. Since nucleotide and deduced amino acid sequences of ser2 of all tested isolates are identical, this heterogeneity may be attributed to differences in enzyme expression levels or post-translational modifications. PMID:26874224

  3. 17th colloquium on long-time behaviour of heat-resistant steels and high-temperature materials

    This volume contains 17 lectures on the following subjects (selection): Microstructural description of the creep behaviour of the Ni-based superalloy IN 738 LC based on the iso-structural model; the effect of Nb, V, N and Al on the creep rupture strength of 9-12% Cr steels; structure and long-time investigations of 9-12% Cr steels for forged and cast parts; creep tests on samples of welded pipe joints made of X10CrMo V Nb 9-1 steel, evolution of the microstructure during creep stress and annealing of the Martensitic cast steel G-X12 Cr Mo V Nb N 9 1; Micro-structure during cyclic creep in the creep area using the example of Martensitic steel X22 Cr Mo V 12 1; description of crack initiation and progress of hot cracks in heat resisting 1% Cr Mo V castings under creep or fatigue stress; optimisation and verification of creep equations for high temperature materials, single stage and multi-stage long-time creep fatigue behaviour of heat-resistant steels; cyclic creep behaviour of heat-resistant steels under intermittent stress and on the tension/compression area. (orig./MM)

  4. Sources and risk factors for contamination, survival, persistence, and heat resistance of Salmonella in low-moisture foods.

    Podolak, Richard; Enache, Elena; Stone, Warren; Black, Darryl G; Elliott, Philip H

    2010-10-01

    Sources and risk factors for contamination, survival, persistence, and heat resistance of Salmonella in low-moisture foods are reviewed. Processed products such as peanut butter, infant formula, chocolate, cereal products, and dried milk are characteristically low-water-activity foods and do not support growth of vegetative pathogens such as Salmonella. Significant food safety risk might occur when contamination takes place after a lethal processing step. Salmonella cross-contamination in low-moisture foods has been traced to factors such as poor sanitation practices, poor equipment design, and poor ingredient control. It is well recognized that Salmonella can survive for long periods in low-moisture food products. Although some die-off occurs in low-moisture foods during storage, the degree of reduction depends on factors such as storage temperature and product formulation. The heat resistance of Salmonella is affected by many factors, mostly by strain and serotypes tested, previous growth and storage conditions, the physical and chemical food composition, test media, and the media used to recover heat-damaged cells. Salmonella heat resistance generally increases with reducing moisture. Care must be taken when applying published D- and z-values to a specific food process. The product composition and heating medium and conditions should not be significantly different from the product and process parameters used by the processors. PMID:21067682

  5. Induction of Heat Resistance in Wheat Coleoptiles by 4-Hydroxybenzoic Acid: Connection with the Generation of Reactive Oxygen Species

    Yastreb T.O.

    2012-08-01

    Full Text Available The effect of 4-hydroxybenzoic acid (4-HBA on resistance of coleoptiles of 4-day-old etiolated seedlings of wheat (Triticum aestivum L., cv. Elegiya to damaging heating (10 min at 43°C and possible dependence of this effect on changes in the activities of enzymes producing and scavenging reactive oxygen species (ROS were investigated. Treatment of coleoptiles with 10 μM 4-HBA resulted in enhancing of superoxide anion-radical generation and maintaining of hydrogen peroxide content there in. Increasing of the rate of ROS production was significantly suppressed by inhibitors of NADPH oxidase (α-naphthol and peroxidase (salicylhydroxamic acid. Under the influence of 4-HBA the activities of superoxide dismutase and apoplastic forms of peroxidase were increased. The activity of oxalate oxidase and catalase has not changed. Exogenous 4-HBA improved coleoptiles heat resistance and its effects were comparable with the influence of salicylic acid. Antioxidant agent BHT (butylhydroxytoluene, inhibitors of NADPH oxidase and peroxidase significantly reduced the increasing of wheat coleoptiles heat resistance, caused by 4-HBA action. It was concluded that 4-HBA influence on coleoptiles heat resistance is realized with the ROS mediation.

  6. Electromagnetic property of SiO2-coated carbonyl iron/polyimide composites as heat resistant microwave absorbing materials

    Heat resistant microwave absorbing materials were prepared by compression molding method, using polyimide resin as matrix and SiO2 coated carbonyl iron (CI) as filler. The SiO2 coated CI particles were prepared by Stober process. The microwave absorbing properties and the effect of heat treatment on the electromagnetic properties of SiO2 coated CI/polyimide composites were investigated. When the content of SiO2 coated CI is 60 wt%, the value of minimum reflection loss decreases from ?25 dB to ?33 dB with the thickness increases from 1.5 mm to 2.1 mm. According to the thermal-gravimetric analyses (TGA) curves, the polyimide matrix can be used at 300 C for long time. The complex permittivity of the composites slightly increases while the complex permeability almost keeps constant after heat treatment at 300 C for 10 h, which indicating that the composites can be used at elevated temperature as microwave absorbing materials at the same time have good heat resistance and microwave absorption. - Highlights: Polyimide as matrix and SiO2 coated carbonyl iron as filler. The SiO2 coated CI shows good absorbing properties. The composites have good heat resistance

  7. Electrochemical impedance spectroscopy of metal alloys in the space transportation system launch environment

    Calle, Luz

    1990-01-01

    AC impedance measurements were performed to investigate the corrosion resistance of 18 alloys under conditions similar to the Space Transportation System (STS) launch environment. The alloys were: (1) zirconium 702; (2) Hastelloy C-22, C-276, C-4, and B-2; (3) Inconel 600 and 825; (4) Ferralium 255; (5) Inco Alloy G-3; (6) 20Cb-3; (7) SS 904L, 304LN, 316L, 317L, and 304L; (8) ES 2205; and (9) Monel 400. AC impedance data were gathered for each alloy at various immersion times in 3.55 percent NaCl-0.1N HCl. Polarization resistance values were obtained for the Nyguist plots at each immersion time using the EQUIVALENT CIRCUIT software package available with the 388 electrochemical impedance software. Hastelloy C-22 showed the highest overall values for polarization resistance while Monel 400 and Inconel 600 had the lowest overall values. There was good general correlation between the corrosion performance of the alloys at the beach corrosion testing site, and the expected rate of corrosion as predicted based on the polarization resistance values obtained. The data indicate that electrochemical impedance spectroscopy can be used to predict the corrosion performance of metal alloys.

  8. On evaluation of tensile stress-strain diagrams for heat resistant metallic materials

    Temperature and cyclic loading are experimentally studied for their effect on tensile stress-strain diagrams of high temperature nickel alloys. Four types of diagrams are singled out as dependent on the temperature level. It is shown that on the whole cyclic loadings decrease characteristics of the short-term strength. The effect of the tensile stress-strain diagram displacement towards hardening is revealed in the region of high temperatures as against under pure static loading

  9. Collect Available Creep-Fatigue Data and Study Existing Creep-Fatigue Evaluation Procedures for Grade 91 and Hastelloy XR

    Tai Asayama; Yukio Tachibana

    2007-09-30

    This report describes the results of investigation on Task 5 of DOE/ASME Materials Project based on a contract between ASME Standards Technology, LLC (ASME ST-LLC) and Japan Atomic Energy Agency (JAEA). Task 5 is to collect available creep-fatigue data and study existing creep-fatigue evaluation procedures for Grade 91 steel and Hastelloy XR. Part I of this report is devoted to Grade 91 steel. Existing creep-fatigue data were collected (Appendix A) and analyzed from the viewpoints of establishing a creep-fatigue procedure for VHTR design. A fair amount of creep-fatigue data has been obtained and creep-fatigue phenomena have been clarified to develop design standards mainly for fast breeder reactors. Following this, existing creep-fatigue procedures were studied and it was clarified that the creep-fatigue evaluation procedure of the ASME-NH has a lot of conservatisms and they were analyzed in detail from the viewpoints of the evaluation of creep damage of material. Based on the above studies, suggestions to improve the ASME-NH procedure along with necessary research and development items were presented. Part II of this report is devoted to Hastelloy XR. Existing creep-fatigue data used for development of the high temperature structural design guideline for High Temperature Gas-cooled Reactor (HTGR) were collected. Creep-fatigue evaluation procedure in the design guideline and its application to design of the intermediate heat exchanger (IHX) for High Temperature Engineering Test Reactor (HTTR) was described. Finally, some necessary research and development items in relation to creep-fatigue evaluation for Gen IV and VHTR reactors were presented.

  10. Magnesium Cermets and Magnesium-Beryllium Alloys

    The paper describes some results of work on the development of magnesium-magnesium oxide cermets and of super heat-resistant magnesiumberyllium alloys produced by powder metallurgical methods. The introduction of even a minute quantity of finely dispersed magnesium oxide into magnesium results in a strengthening of the material, the degree of which increases with increased magnesium oxide concentration, although variation of this concentration within the limits of 0.3 to 5 wt.% has a comparatively slight effect on the corresponding variation in the short-term strength over the whole range of temperatures investigated. At 20oC, in the case of the cermets, σβ = 28 to 31 kg/mm2 and δ = 3 .5 to 4.5%; at 500oC σβ = 2.6 to 3.2 kg/mm2 and δ =30 to 40%. The positive effect of the finely dispersed oxide phase is particularly evident in protracted tests. For magnesium cermets, σ (300)/100 = 2.2 kg/mm2. Characteristic of the mixtures is the high thermal stability of the strength properties, linked chiefly with the thermodynamic stability of the strength-giving oxide phase in the metal matrix. The use of powder metallurgical methods has yielded super heat-resistant magnesium-beryllium alloys containing heightened concentrations of beryllium (PMB alloys). In their strength characteristics PMB alloys are close to Mg-MgO cermets, but the magnesium-beryllium alloys have a degree and duration of resistance to high temperature oxidation which exceeds the corresponding qualities of the magnesium alloys at present known. Thus, in air of 580oC, PMB alloys with 2 to 5% beryllium maintain a high resistance to oxidation for a period of over 12000 to 14000 h. This long-term heat resistance is chiefly a result of the amount of beryllium in the alloy, and increases with increasing beryllium content. PMB alloys are also marked by high resistance to short bursts of overheating. Magnesium cermets and magnesium-beryllium alloys, with their enhanced high-temperature stability, are capable of finding extensive application in various branches of technology. (author)

  11. Oxidation of high-temperature alloys (superalloys) at elevated temperatures in air: I

    Four commercial alloys - Hastelloy C-4, alloy 1.4306S (SS 304L), Incoloy 800H, and Incoloy 825 - were studied for their oxidation behavior at elevated temperatures. Specimens were exposed to air from 600 to 1200 degree C for 1 to 400 hr. Reaction kinetics of oxidation were determined, and the morphology of the surface-oxide scales was investigated. Hastelloy C-4 showed better resistance to oxidation for exposure temperatures up to 1000 degree C in comparison with the other three alloys. In this temperature range, it follows a cubic rate law of oxidation due to formation of uniform, protective, and adherent oxide scales. The latter three alloys obeyed the parabolic rate law at 1000 degree C and 1200 degree C, but for lower temperatures a mixed behavior was shown. The oxide layer developed on the alloy 1.4306S was always in the form of stratified nodules/warts. For longer exposures the nodules joined each other to form continuous but discrete layers. Incoloy 800H and Incoloy 825 behaved in an almost identical manner, their reaction kinetics being governed by the parabolic rate law throughout the temperature range. Oxide spalling was observed at all temperatures. In contrast to Incoloy 800H the Incoloy 825 was totally oxidized for longer exposures at 1200 degree C. 16 refs., 12 figs., 1 tab

  12. Wrought stainless steel compositions having engineered microstructures for improved heat resistance

    Maziasz, Philip J [Oak Ridge, TN; Swindeman, Robert W [Oak Ridge, TN; Pint, Bruce A [Knoxville, TN; Santella, Michael L [Knoxville, TN; More, Karren L [Knoxville, TN

    2007-08-21

    A wrought stainless steel alloy composition includes 12% to 25% Cr, 8% to 25% Ni, 0.05% to 1% Nb, 0.05% to 10% Mn, 0.02% to 0.15% C, 0.02% to 0.5% N, with the balance iron, the composition having the capability of developing an engineered microstructure at a temperature above 550.degree. C. The engineered microstructure includes an austenite matrix having therein a dispersion of intragranular NbC precipitates in a concentration in the range of 10.sup.10 to 10.sup.17 precipitates per cm.sup.3.

  13. Effects of gamma irradiation on two heat resistant moulds: Aspergillus fumigatus and Paecilomyces variotii isolated from margarine

    Gumus, Tuncay; Gecgel, Umit; Demirci, A. Sukru; Arici, Muhammet

    2008-05-01

    The present study was undertaken to evaluate the effect of gamma irradiation on two heat-resistant moulds, namely Aspergillus fumigatus and Paecilomyces variotii isolated from margarine samples. The irradiation process of these moulds was carried out in a 60Co gamma ( ?) irradiator at average absorbed doses of 1, 3, 5 and 7 kGy for exposure times of 52, 156, 260 and 364 min, respectively. The average D10 value for A. fumigatus was 1.080.08 kGy while it was 0.590.10 kGy for P. variotii. Consequently, the sensitivity of P. variotii against ? irradiation was more than A. fumigatus.

  14. Effects of gamma irradiation on two heat resistant moulds: Aspergillus fumigatus and Paecilomyces variotii isolated from margarine

    The present study was undertaken to evaluate the effect of gamma irradiation on two heat-resistant moulds, namely Aspergillus fumigatus and Paecilomyces variotii isolated from margarine samples. The irradiation process of these moulds was carried out in a 60Co gamma (?) irradiator at average absorbed doses of 1, 3, 5 and 7 kGy for exposure times of 52, 156, 260 and 364 min, respectively. The average D10 value for A. fumigatus was 1.080.08 kGy while it was 0.590.10 kGy for P. variotii. Consequently, the sensitivity of P. variotii against ? irradiation was more than A. fumigatus

  15. Phase composition and structure of NiAl base alloys of Ni-Al-Co-M systems where M-Ti, Zr, Hf, V, Nb, Ta, Cr, Mo

    A study was made into the effect of transition metals (0.27-23 at.% of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo) on phase composition and microstructure of (? + ?)-alloys of the Ni-Al-Co system. It is concluded that for designing heat resistant nickel base alloys with the density not exceeding 7.3 g/cm3 the two-phase (? + ?) alloys can be taken as a basis. In alloys of the (29-43) Ni-(20-25)Al-(32-34)Co compositions with 1-1.8 at%Mo, Ta, Nb or V the occurrence of gamma'-phase secondary precipitations is shown to be possible. Ti and Cr contents may reach 3 and 12 at.% respectively. Alloying elements promote an increase of main strengthening element (Co) content in ?-phase and enhance heat resistance of Ni-Al-Co alloys. 3 refs.; 6 figs

  16. Electromagnetic property of SiO2-coated carbonyl iron/polyimide composites as heat resistant microwave absorbing materials

    Wang, Hongyu; Zhu, Dongmei; Zhou, Wancheng; Luo, Fa

    2015-02-01

    Heat resistant microwave absorbing materials were prepared by compression molding method, using polyimide resin as matrix and SiO2 coated carbonyl iron (CI) as filler. The SiO2 coated CI particles were prepared by Stober process. The microwave absorbing properties and the effect of heat treatment on the electromagnetic properties of SiO2 coated CI/polyimide composites were investigated. When the content of SiO2 coated CI is 60 wt%, the value of minimum reflection loss decreases from -25 dB to -33 dB with the thickness increases from 1.5 mm to 2.1 mm. According to the thermal-gravimetric analyses (TGA) curves, the polyimide matrix can be used at 300 °C for long time. The complex permittivity of the composites slightly increases while the complex permeability almost keeps constant after heat treatment at 300 °C for 10 h, which indicating that the composites can be used at elevated temperature as microwave absorbing materials at the same time have good heat resistance and microwave absorption.

  17. Effect of microstructural changes during creep on the creep rate at 823 K in type 304 heat resistant steel

    The effect of stress on the shape of creep rate - time curves at 823 K in type 304 heat resistant steel has been investigated. The stress conditions of creep tests at 823 K, stress range from 157 MPa to 333 MPa are higher than the 0.2% proof stress of the type 304 heat resistant steel. At the stresses higher than 265 MPa, creep rate decreases monotonously in a transient creep stage and increases monotonously in an acceleration one, such shape of creep rate - time curve is called as normal type. Contrast to this shape in higher stress range of 333 to 265 MPa, the shape of the creep rate - time curve in the medium range from 235 to 196 MPa turns to the different one with two local minima due to the early inflection, and that shape of creep rate - time curve was designated as W-type. With further decreasing the stress, early inflection in creep rate - time curve turns to obscure one, and almost disappeared at the stresses lower than 177 MPa. This shape of creep rate - time curve was designated as V-type. The main cause of changes in the shape of creep rate - time curve is the occurrence of the early infection in creep rate - time curve. Microstructural observation and changes in hardness have indicated that this early inflection has been caused by the dispersion strengthening precipitation of M23C6 on dislocations. (author)

  18. Heat-resistivity and local structure of new nuclear waste glass composed of calcium aluminate and lead phosphate

    Aluminophosphate glass with a batch composition of 30CaO15Al2O35Fe2O325PbO25P2O5 was prepared as a potential host for the high-level nuclear wastes. This ''base glass'' consists of highly heat-resistant 60CaO(40-x)Al2O3xFe2O3 glass and water-resistant lead metaphosphate glass, Pb(PO3)2, which is known to have -103 times higher water-resistivity than conventional borosilicate glass. Two crystallization temperatures (Tc) of 650-671 and 668-693 degC were determined from the differential thermal analysis (DTA) of the ''base glass''. Large activation energies of 4.2 and 4.9 eV were obtained from a Kissinger plot of the Tc values. Nuclear waste ''model glass'' containing 10 stable isotopes with the mass numbers of 90-100 (Sr, Y, Zr, Nb, Mo) and 135-145 (Ba, La, Ce, Pr, Nd) also shows high heat-resistivity. 57Fe Mossbauer spectrum indicates that Fe(III) and Fe(II) are ionically bonded to distorted PO4 tetrahedra at the sites of network modifier. (author)

  19. Rolling contact fatigue behaviour of heat resistant bearing steels at high operational temperatures

    An approach was made to estimate the endurance limit in rolling contact fatigue in dependence of the operational conditions for the bearing steels M50 (AMS 6491), M50 NiL (AMS 6278) and the nitrogen-alloyed Cronidur 30 (AMS 5898) by investigating the changes in the residual stress profiles after 5 million cycles of over-rolling. Real main shaft bearings with a pitch diameter of 168 mm have been tested. To simulate the heat generated in the turbine engines even under boundary operational conditions oil inlet temperatures between 80 and 210 C have been applied, the rotational speed has been varied between 2500 and 14000 r/min and the interference fit has been changed to produce different hoop stress levels. (orig.)

  20. On the correlation between heat resistance and durable heat strength os steels

    In determining the high-temperature properties of metallic materials a combined evaluation of thermal stability and high-temperature strength is recommended, based on a comparison of limiting temperatures calculated from the parameteric thermal stability diagram and the temperature dependence of the stress-rupture strength. Criteria are proposed for harmonic alloying of materials designed for high-temperature operation in oxidizing gaseous media under static loads. Calculations based on experimental data indicate that the pearlitic steels 12X1MF, 12X2MFSR and 12X1MFB do not have satisfactory thermal stability, whereas medium- and high-chromium steels and chromium-nickel austenitic steels are characterized by a favourable thermal stability to high-temperature strength ratio. Increasing the high-temperature strength of steels improves the relationship between thermal stability and high-temperature strength. (author)

  1. Development of Mg-Al-Zn based diecasting alloys for elevated temperature applications

    Kim, J.M.; Park, B.K.; Jun, J.H.; Kim, K.T.; Jung, W.J. [Advanced Materials Development Center, Korea Inst. of Industrial Technology, Incheon (Korea); Shin, K. [Dept. of Metallurgy and Materials Science, Changwon National Univ., Changwon (Korea)

    2005-07-01

    Effort has been devoted to develop new heat resistant diecasting alloys based on Mg-Al-Zn system in this research. Small amounts of cerium-rich misch metal and antimony additions to AZ91 alloy could enhance the tensile strength at an elevated temperature while keeping the good castability. The increase of Zn content in Mg-8(wt%)Al-xZn-0.5RE-0.5Sb alloys, was observed to significantly increase the yield strength at 175 C although the castability such as fluidity and hot cracking resistance was slightly decreased. Intensive microstructural investigation on the new Mg-Al-Zn diecasting alloys was also carried out. (orig.)

  2. Air contamination effects on the compatibility of liquid lithium with molybdenum, TZM, niobium, stainless steels, nickel and Hastelloy N in stainless steel vessels at 6000C

    The effects of nonmetallic impurities on the compatibility of liquid lithium with molybdenum, TZM, niobium, type 304 and type 316 stainless steels, nickel and Hastelloy N were investigated. Three compatibility tests (test I, test II and test III), classified by the grade of air contamination of the lithium, were conducted at 6000C for about 1000 h in stainless steel vessels. In each test the above-mentioned specimens were immersed together in the lithium. In test I weight gain was observed for all the specimens except nickel and Hastelloy N. However, in test II and test III, weight loss was observed for all the specimens. MoNi3 was produced on the surface of the molybdenum and TZM specimens as a result of the reaction between molybdenum and nickel dissolved in the liquid lithium. NbNsub(0.9)Osub(0.1) was observed on the surface of niobium specimens in test I and test II, and Nb2N in test II and test III. The surface of the stainless steel specimens in test II and test III was depleted with nickel and chromium elements, and deteriorated. The corrosion rates of the test specimens in test III were about 2, 5, 26 and 22/?m/yr for molybdenum or TZM, niobium, type 304 stainless steel and type 316, respectively. Nickel and Hastelloy N were severely attacked by liquid lithium at 6000C. These results were obtained for liquid lithium with a high nickel concentration. (Auth.)

  3. Creep-rupture behaviour of four high temperature alloy weldments at 850 and 950 deg C

    Creep tests were conducted on weldments made with Hastelloy X (matching filler), Nimonic 86 (Inconel 112 filler), Inconel 617 (Inconel 112 filler) and Alloy 800H (Thermanit 21/33 filler) at 850 and 950 deg C in air and in controlled impurity helium. Plain and notched samples were used, the notch being in the weld metal. At 850 deg C, the welds achieved rupture strengths close to those expected for the parent materials. At 950 deg C, however, shortfalls in expected strength were found for the Hastelloy X and Inconel 617 welds. In Hastelloy X, welding reduced the rupture strength of the parent material but in the Inconel 617 weld, failure reflected inadequate strength of the filler. Various failure types were noted but failure often occurred near a structural or strength transition. In particular, a heat affected zone type of failure was promoted by a combination of strong filler and weaker parent. Notched samples achieved or exceeded rupture lives of their companion plain samples. Environmental effects were small, producing no consistent effect on rupture life although oxidation rates and surface crack nucleation were greater in air. Oxidation resistance of Thermanit 21/33 in air at 950 deg C was poor. (author)

  4. Study on high temperature design methodology of heat-resistant materials for GEN-IV systems

    Ryu, Woo Seog; Kim, D. W.; Kim, S. H.; Kim, W. G.; Kim, J. H.; Park, D. G.; Yoon, J. H.; Lee, H. Y.; Hing, J. H

    2005-08-15

    Analysis of the existing high temperature design and assessment codes such as US(ASME-NH,Draft Code Case for Alloy 617), France(RCC-MR), UK(R5), Japan(BDS/DDS/FDS) for Gen IV reactor structure has been carried out. In addition the scope and fields for research and development is needed in the future have been defined. For assessing the high temperature creep cracks, time dependent fracture mechanics (TDFM) parameters of the C and Ct were analyzed. The creep propagation data were obtained from the creep crack growth tests for type 316LN stainless steels, and creep crack growth testing machine for Gen-IV system up to 950 .deg. C was set up. Damage mechanism and causes for creep-fatigue were investigated. The difference between prediction creep-fatigue life and experimental life were investigated. Material properties for analysis creep-fatigue damage were recommended. The assessment procedure (Draft) on creep-fatigue crack initiation has been developed based on the technical appendix A16 of French RCC-MR code. Ultrasonic wave signal against creep ruptured specimens of type 316LN stainless steel was obtained. It was identified that creep damage can be evaluated by ultrasonic method. The NDT techniques evaluated include Barkhausen noise, magnetic hysteresis parameters, positron annihilation, X-ray diffraction and small angle neutron scattering. Experimental procedure and evaluation method of material integrity were developed through the fracture toughness test of Cr-Mo steel.

  5. Response Surface Design Model to Predict Surface Roughness when Machining Hastelloy C-2000 using Uncoated Carbide Insert

    This paper presents to develop of the response surface design model to predict the surface roughness for end-milling operation of Hastelloy C-2000 using uncoated carbide insert. Mathematical model is developed to study the effect of three input cutting parameters includes the feed rate, axial depth of cut and cutting speed. Design of experiments (DOE) was implemented with the aid of the statistical software package. Analysis of variance (ANOVA) has been performed to verify the fit and adequacy of the developed mathematical model. The result shows that the feed rate gave the more effect on the both prediction values of Ra compared to the cutting speed and axial depth of cut. SEM and EDX analyses were performed in different cutting conditions. It can be concluded that the feed rate and cutting force give the higher impact to influence the machining characteristics of surface roughness. Thus, the optimizing the cutting conditions are essential in order to improve the surface roughness in machining of Hastlelloy C-2000.

  6. Alloying of vacuum-melted tungsten

    Discussed is the possibility to lower the temperature of the plastic-brittle transition, to improve the technological plasticity of the melted tungsten through its alloying with the ZrC, HfC, NbC and TaC carbides and substituting elements. The mechanism of the solidly soluted strengthening in the alloys of the tungsten with rhenium and molybdenum are shown. Represented are the data, regarding the researches aimed at fixing the phase zones in the tungsten side of the W-C-Zr, W-C-Hf, W-C-Nb, W-C-Ta, W-C-Re and W-C-Os ternary. It is shown, that the tungsten alloys strengthening with the MeC-type disperse carbide-ensures a combination of the technological plasticity with good heat-resisting properties

  7. Preparation and characterization of Fe–Al intermetallic layer on the surface of T91 heat-resistant steel

    A Fe–Al intermetallic layer was formed on the surface of T91 heat-resistant steel by a molten aluminum hot-dipping and heat diffusion treatment. It is shown that the layer was composed of Al, FeAl3 and Fe2Al5 phases in the as-dipped state while only Fe3Al phase retained after the heat treatment. The intermetallic layer exhibited typical columnar grain structure after the heat treatment, and the thickness of aluminizing layer was increased from 55 μm at 760 °C to around 100 μm at 1050 °C heat treatment. Such a phase composition and grain morphology are favorable for the oxidation and corrosion resistance of T91 steel

  8. Effect of tempering treatment before aging on the microstructure and mechanical properties of ferritic heat-resistant steels

    This study investigated the effect of the tempering before aging on the precipitation of Laves phase and mechanical properties of 10Cr-6W and 10Cr-6W-3Co ferritic heat-resistant steels. Laves phase was precipitated by aging, which increased tensile strength but decreased elongation and impact value. Toughness was rapidly decreased by the presence of the very fine disk-like Laves phase precipitated at early aging stage. Strength and impact value were decreased by tempering treatment and that is due to the increase of the particle number per unite area and to larger particle size of Laves phase. Laves phase increased by adding Co, and consequently strength was increased and elongation and toughness were decreased

  9. Effects of gamma irradiation on two heat resistant moulds: Aspergillus fumigatus and Paecilomyces variotii isolated from margarine

    Gumus, Tuncay [Agricultural Faculty, Department of Food Engineering, 59030, Namik Kemal University, Tekirdag (Turkey)], E-mail: tuncaygumus@tu.tzf.edu.tr; Gecgel, Umit; Demirci, A. Sukru; Arici, Muhammet [Agricultural Faculty, Department of Food Engineering, 59030, Namik Kemal University, Tekirdag (Turkey)

    2008-05-15

    The present study was undertaken to evaluate the effect of gamma irradiation on two heat-resistant moulds, namely Aspergillus fumigatus and Paecilomyces variotii isolated from margarine samples. The irradiation process of these moulds was carried out in a {sup 60}Co gamma ({gamma}) irradiator at average absorbed doses of 1, 3, 5 and 7 kGy for exposure times of 52, 156, 260 and 364 min, respectively. The average D{sub 10} value for A. fumigatus was 1.08{+-}0.08 kGy while it was 0.59{+-}0.10 kGy for P. variotii. Consequently, the sensitivity of P. variotii against {gamma} irradiation was more than A. fumigatus.

  10. Diffractometric examination of the structure of heat-resisting steel-based coatings in different measurement geometries

    Kucharska, Barbara

    2011-10-01

    Coatings of the composition of 310S heat-resisting steel dopped Al and Ir additions, deposited on a substrate of the same steel by the magnetron sputtering method, were examined. The measurements were made in the classical Bragg-Brentano geometry and by the GXRD method. With the fixed and different position of the coated sample by rotating the sample by angles ψ. The coating as deposited and after being soaked at 400°C for 15 minutes was subjected to examinations. The examination carried out have shown that coatings may have a unique, subtle structure which is metastable and undergoes irreversible changes in the temperatures up to 400°C. It has been found that in the outermost coating zones and zones closer to the substrate, areas occur in the coating structure, which have the different lattice parameter compared to the basic phase. Additionaly, the local period of the structure equal 5.9 nm was found.

  11. Microstructure and mechanical properties of heat-resistant 12% Cr ferritic-martensitic steel EK-181 after thermomechanical treatment

    Polekhina, N. A.; Litovchenko, I. Yu.; Tyumentsev, A. N.; Astafurova, E. G.; Chernov, V. M.; Leontyeva-Smirnova, M. V.

    2015-10-01

    The effect of high-temperature thermomechanical treatment (TMT) with the deformation in the austenitic region on the features of microstructure, phase transformations and mechanical properties of low-activation 12% Cr ferritic-martensitic steel EK-181 is investigated. It is established, that directly after thermomechanical treatment (without tempering) the sizes and density of V(CN) particles are comparable with those after a traditional heat treatment (air quenching and tempering at 720°C, 3 h), where these particles are formed only during tempering. It causes the increasing of the yield strength of the steel up to ≈1450 MPa at room temperature and up to ≈430 MPa at the test temperature T = 650°C. The potential of microstructure modification by this treatment aimed at improving heat resistance of steel is discussed.

  12. High temperature ductility of austenitic alloys exposed to thermal neutrons

    Loss of high temperature ductility due to thermal neutron irradiation was examined by slow strain rate test in vacuum up to 10000C. The results on two heats of Hastelloy alloy X with different boron contents were analyzed with respect to the influence of the temperatures of irradiation and tensile tests, neutron fluence and the associated helium production due to nuclear transmutation reaction. The loss of ductility was enhanced by increasing either temperature or neutron fluence. Simple extrapolations yielded the estimated threshold fluence and the end-of-life ductility values at 900 and 10000C in case where the materials were used in near-core regions of VHTR. The observed relationship between Ni content and the ductility loss has suggested a potential utilization of Fe-based alloys for seathing of the neutron absorber materials

  13. [Properties of the enzymes of energy supply in the common frog under various physiological states. II. Changes in the heat resistance of adenosine triphosphatases and succinate dehydrogenase].

    Glushankova, M A; Ivanova, G I; Pisareva, L N

    1986-05-01

    The heat resistance of SDG, Na, K-ATPase and Mg-ATPase of the grass frog was determined in January, March and May, the number of animals examined being 30-40 in either experiment. It was found that the average level of the heat resistance of the enzymes studied shows significant, often differently directed changes, which depend on the physiological state of an organism. Negligible correlation between the thermal sensitivity of different enzymes of an organism during hibernation, completely disappear during the activity state. PMID:3016954

  14. Solute Transport Proteins and the Outer Membrane Protein NmpC Contribute to Heat Resistance of Escherichia coli AW1.7▿

    Ruan, Lifang; Pleitner, Aaron; Gänzle, Michael G.; McMullen, Lynn M.

    2011-01-01

    This study aimed to elucidate determinants of heat resistance in Escherichia coli by comparing the composition of membrane lipids, as well as gene expression, in heat-resistant E. coli AW1.7 and heat-sensitive E. coli GGG10 with or without heat shock. The survival of E. coli AW1.7 at late exponential phase was 100-fold higher than that of E. coli GGG10 after incubation at 60°C for 15 min. The cytoplasmic membrane of E. coli AW1.7 contained a higher proportion of saturated and cyclopropane fat...

  15. New structural high strength rationally alloyed steels

    New developments in high strength structural steels are reported. Properties and perspective fields of application are described for the following materials: austenitic chromium steels with ultra equilibrium nitrogen content, steels with nitrogen martensite structure, microalloyed ferritic-pearlitic steels with decreased concentrations of Mn and Ni, high ductility heat resisting steels, nonmagnetic chromium free Mn-Ni-Cu-V-C steels and iron powder alloys with superhard carbon phases. Steel 02Kh12G14N4YuM is recommended to be used for parts and assemblies of nuclear power plants

  16. Influence of heat treatments on the mechanical properties and microstructure of a 50Cr-50Ni niobium containing alloy

    Caironi, G.; Gariboldi, E.; Silva, G.; Vedani, M.

    1993-01-01

    A heat resisting 50Cr-50Ni niobium-containing casting alloy, particularly developed for petrochemical plants was studied. The alloy combines high temperature strength with fuel ash corrosion resistance. However, during service, the exposure to high temperatures gives rise to precipitation of embrittling phases, strongly depleting the material ductility. Therefore, studies on the thermal aging at 700° C were carried out either in the as cast condition or after heat treatments at 1000, 1075, 11...

  17. Corrosion Behavior of Alloys in Molten Fluoride Salts

    Zheng, Guiqiu

    The molten fluoride salt-cooled high-temperature nuclear reactor (FHR) has been proposed as a candidate Generation IV nuclear reactor. This reactor combines the latest nuclear technology with the use of molten fluoride salt as coolant to significantly enhance safety and efficiency. However, an important challenge in FHR development is the corrosion of structural materials in high-temperature molten fluoride salt. The structural alloys' degradation, particularly in terms of chromium depletion, and the molten salt chemistry are key factors that impact the lifetime of nuclear reactors and the development of future FHR designs. In support of materials development for the FHR, the nickel base alloy of Hastelloy N and iron-chromium base alloy 316 stainless steel are being actively considered as critical structural alloys. Enriched 27LiF-BeF2 (named as FLiBe) is a promising coolant for the FHR because of its neutronic properties and heat transfer characteristics while operating at atmospheric pressure. In this study, the corrosion behavior of Ni-5Cr and Ni-20Cr binary model alloys, and Hastelloy N and 316 stainless steel in molten FLiBe with and without graphite were investigated through various microstructural analyses. Based on the understanding of the corrosion behavior and data of above four alloys in molten FLiBe, a long-term corrosion prediction model has been developed that is applicable specifically for these four materials in FLiBe at 700C. The model uses Cr concentration profile C(x, t) as a function of corrosion distance in the materials and duration fundamentally derived from the Fick's diffusion laws. This model was validated with reasonable accuracy for the four alloys by fitting the calculated profiles with experimental data and can be applied to evaluate corrosion attack depth over the long-term. The critical constant of the overall diffusion coefficient (Deff) in this model can be quickly calculated from the experimental measurement of alloys' weight loss due to Cr depletion. While many factors affect the Deff such as the grain boundary type, grain size, precipitates, initial Cr concentration as well as temperature, this model provides a methodology for estimating corrosion attack depth of alloys in molten fluoride salts obviating the need for difficult and challenging experiment.

  18. Predictive model for the reduction of heat resistance of Listeria monocytogenes in ground beef by the combined effect of sodium chloride and apple polyphenols

    We investigated the combined effect of three internal temperatures (57.5, 60, and 62.5C) and different concentrations (0 to 3.0 wt/wt %) of sodium chloride (NaCl) and apple polyphenols (APP), individually and in combination, on the heat-resistance of a five-strain cocktail of Listeria monocytogenes ...

  19. Reaction of several iron and nickel based alloys with sintered Li2O pellets

    The reaction of type 316 stainless steel, Incoloy 800, Hastelloy X-R, Inconel 600 and pure Ni with sintered Li2O pellets has been studied between 800 and 11000C under dynamic vacuum. The reaction products were analyzed by means of metallographic, microprobe and X-ray diffraction methods. The reactions proceeded measurably between 800 and 9500C and appreciably at 10000C, being greatest with Incoloy 800 and least with Hastelloy X-R. Among the primary alloy constituents, chromium was exclusively attacked by lithium and oxygen diffusing from the Li2O into the alloys to form LiCrO2. This phase grew into a reaction zone (subscale) of uniform thickness beneath the surface of each alloy. Preferential growth of LiCrO2 along the grain boundaries was observed only in the case of Inconel 600 below 9500C. On the other hand, iron diffused toward the Li2O pellets to form volatile Li5FeO4. However, any reaction product associated with Ni was not detected and Ni metal was little attacked by the Li2O pellet over the whole range of reaction temperature. (Auth.)

  20. Role of alloying elements in oxide film formation on VT14 alloy at 1100 deg C

    The methods of metallographic, X-ray structural, spectral analyses and microhardness measurements have been used to study the role of alloying elements of the VT14 alloy (5.3% Al - 3.3% Mo - 1.1% V) in the oxide film formation and their effect on the heat resistance level at the temperature of 1100 deg C. On the basis of results obtained the following procedure of oxide film formation is suggested. After oxidation at 1000 deg C for 1 hour the scale consists of TiO2 and Al2O3, HoO3 oxides. The increase of holding-up brings about the destruction of Al2O3 layer and the role of molybdenum and vanadium oxides that have a low melting temperature and are present in the liquid phase, increases. These processes intensify oxidation of the VT14 alloy

  1. Microstructural analysis as the indicator for suitability of weld repairing of the heat resistant Cr - Ni steel

    Odanovi?, Z.

    2010-08-01

    Full Text Available Metallurgical evaluation was performed on a fractured column tube of the reformer furnace in an ammonia plant. The tubes were manufactured from centrifugally cast heat resistant steel HK 40. Optical and scanning electron microscope (SEM were used for microstructural and fracture analysis. For composition determination of the microconstituents energy dispersive X ray spectroscopy (EDS was used. To evaluate mechanical properties, hardness and microhardness measurements were performed. Investigations based on the microstructural features with the idea to indicate suitability of weld repair of the column were performed in this study. It was observed that the crack initiation, caused by oxidation/corrosion and thermal stresses induced by temperature gradient, appeared in the inner side of the tube wall and propagation occurred along grain boundaries. The results clearly showed the presence of an irregular microstructure which contributed to crack propagation through the tube wall. An occurrence of precipitated needle-shaped carbides/carbonitrides and brittle ? phase was also identified in the microstructure. Results of the microstructural and fracture analysis clearly indicate that reformer furnace columns made of heat resistant steel HK 40 were unsuitable for weld repair.

    La evaluacin metalrgica se realiz en un tubo de columna con fracturas, que es parte del horno reformador en una planta de amonaco. Estos tubos son fundidos centrfugamente y fabricados en acero resistente al calor, de tipo HK- 40. Para el anlisis microestructural de la fractura se ha utilizado microscopa ptica y electrnica de barrido (SEM. La composicin de los micro-constituyentes se determin por espectrometra de rayos X de energa dispersiva (EDS. Las propiedades mecnicas se evaluaron mediante mediciones de microdureza Vickers. Las investigaciones en este estudio se han llevado a cabo con el fin de demostrar la idoneidad de reparacin por soldadura de columnas en base a sus caractersticas micro-estructurales. Se ha observado que el inicio de la rotura, causada por el efecto de la oxidacin/corrosin y el choque trmico ocasionado por el gradiente de temperatura, aparece en la pared interna del tubo y se propaga a lo largo de los bordes de grano. Los resultados demuestran la presencia de una microestructura irregular que contribuy a la propagacin de la rotura a lo largo de la pared del tubo. En la microestructura tambin se ha registrado la formacin da la precipitacin de fases de carburo/carbn nitrito que aparecen en forma de agujas y fase ? frgil. Con base en los resultados obtenidos, se puede concluir que la microestructura investigada no es idnea para aplicar la reparacin por soldadura.

  2. Fracture toughness of a X alloy under static load

    In the High Temperature Reactor research programm of the French CEA, Hastelloy alloy plates contain mineral fibers used as insulating material and as such prevent the concrete core vessel from receiving excess heat. Due to the high pressure exerted on this insulating materials, the Hastelloy plates are heavily stressed and, therefore, it is important to know their fracture strength. In the case of an elastic, brittle material, the fracture toughness is commonly defined through the Ksub(1c) parameter. But, for plastic materials, measuring Ksub(1c) requires very large samples and it was found more convenient to measure the fracture parameter Jsub(1c) instead of Ksub(1c). Two independent ways were followed to measure Jsub(1c): in the first one the shape of the crack after loading was made apparent by some fatigue cycles; after complete fracture of the sample, the amount of crack extension appears clearly and it becomes possible to generate a J resistance curve. As an alternative, we partially unloaded the specimen to get its compliance: the change in compliance was then supposed to coincide with the start of the crack extension. Finally a finite element code was used to compute the specimen state at the beginning of the crack extension. So we are able to obtain the shape of the Load-Displacement curve and to compare it with the experimental one

  3. Tensile properties of a nickel-base alloy subjected to surface severe plastic deformation

    Tian, J.W. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Dai, K. [Quality Engineering and Software Technology, East Hartford, CT 06108 (United States); Villegas, J.C. [Intel Corporation, Chandler, AZ (United States); Shaw, L. [Department of Chemical, Materials and Biomolecular Engineering, University of Connecticut, Storrs, CT (United States)], E-mail: leon.shaw@uconn.edu; Liaw, P.K. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN (United States); Klarstrom, D.L. [Haynes International, Inc., Kokomo, IN (United States); Ortiz, A.L. [Departamento de Ingenieria Mecanica, Energetica y de los Materiales, Universidad de Extremadura, 06071 Badajoz (Spain)

    2008-10-15

    A surface severe plastic deformation (S{sup 2}PD) method has been applied to bulk specimens of HASTELLOY C-2000 alloy, a nickel-base alloy. The mechanical properties of the processed C-2000 alloy were determined via tensile tests and Vickers hardness measurements, whereas the microstructure was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. The improved tensile strength was related to the nanostructure at the surface region, the residual compressive stresses, and the work-hardened surface layer, all of which resulted from the S{sup 2}PD process. To understand the contributions of these three factors, finite element modeling was performed. It was found that the improved tensile strength could be interpreted based on the contributions of nano-grains, residual stresses, and work hardening.

  4. Optimization and cost of radiation detriment on using egyptian ordinary and heat resistant concrete as shielding materials for power reactors

    This paper discusses the derivation of shield materials to be used as nuclear power plants shields on the basis of ICRP, ALARA principles and cost benefit analysis. It is important to adopt a shielding design philosophy which whilst meeting the requirements of ICRP principles of dose limitation recognizes the practical constraints imposed by the complexity of large projects as power reactors. For each material, its relaxation length and cost per unit volume may be determined to assess the total marginal cost factor for complete shield. The methodology and calculations are presented involving the following: a) Specification of defined egyptian shield materials such as ordinary concrete (o.C.) and ilmenite limonite heat resistant concrete (I.L.H.R.C.) with their physical properties and their relaxation lengths. b) Calculation of the measured dose rate for each type of concrete. c) Calculation of the optimum design dose rate and collective dose equivalent. Hence, the cost of radiation detriment can be assumed proportional to a plant life and the collective dose equivalent with a equal to alpha (α) which is represented by L.E. per man sievert per m2. In this case, the competent authority should specify alpha (α) values to be used in optimization of cost evaluation.4 tab

  5. Effect of boron on microstructures and creep properties of welded joint for high Cr heat resisting steels

    Creep strength of high Cr steel welds is decreased for long-term services at high temperatures due to Type-IV failure occurs in fine-grained HAZ. Aiming at improving the creep strength of HAZ, we have investigated the effect of boron and nitrogen content on the microstructures and creep strength of the 9Cr and 12Cr heat resisting steel welds. It was found that the creep strength of HAZ of these steels could be improved by addition of about 0.01% boron with low nitrogen. For the 9Cr steel, while formation of the fine-grained HAZ structures was inevitable independent of boron and nitrogen contents, the creep strength of HAZ and welded joint could be improved by utilizing the grain boundary strengthening effect of boron. For the 12Cr steel with 0.01% boron and low nitrogen, formation of the fine-grained microstructures during weld thermal cycle was suppressed and the creep strength of HAZ and welded joint was considerably improved. (author)

  6. Microstructural analysis of HAZ in the welded joints of 9Cr heat resistant ferritic steels for fast reactor

    State of microstructure in metallic materials can be expressed as numerical values based on a concept of system free energy, and the energy value is used as a measure of damage analysis of the materials. In this study, change in the system free energy of the FG-HAZ in 9Cr heat resistant ferritic steels during creep is evaluated as summation of chemical free energy, strain energy and surface energy, which are obtained by a series of experiments, i.e., chemical analysis using extracted residues, X-ray diffraction, and scanning transmission electron microscopy. Changing rate of system free energy depends on applied stress and is expressed quantitatively as a numerical formula using rate constants. Furthermore, it is suggested that a steel ruptures when the applied stress exceeds a limited stress which depends on the microstructural state expressed by the system free energy of the state. Thus, the relationship between the limited stress and system free energy makes it possible to predict the rupture life of the steel. (author)

  7. Effect of tempering temperature on the toughness of 9Cr–3W–3Co martensitic heat resistant steel

    Highlights: • Toughness of 9Cr–3W–3Co steel increases with increasing tempering temperature. • Toughness is influenced by hardness of base metal and length of crack propagation path. • Hardness of base metal is influenced by dislocation density and degree of supersaturation of the interstitial atoms. • Length of crack propagation path is influenced by length of the large angle boundaries. - Abstract: Effect of tempering temperature on the toughness of 9Cr–3W–3Co martensitic heat resistant steel was studied on the basis of the microstructures after normalized at 1100 °C for 1 h and then tempered at 740–780 °C for 3 h. With increasing tempering temperature from 740 °C to 780 °C, the absorbed energy of the 9Cr–3W–3Co steel increased greatly from 26 J to 115 J. The change of the toughness with increasing tempering temperature was attributed to the softening of the base metal and the increase of the crack propagation path. The softening of the base metal was caused by the decrease of the dislocation density and the supersaturation of the interstitial atoms. The reason for the increase of the crack propagation path was that the length of the large angle boundaries increased and then the propagation direction of the cleavage crack was deflected more frequently

  8. Study of temperature effect on the physical properties of ilmenite-serpentine heat resistant concrete radiation shields

    A series of experimental studies have been carried out to determine the change in unit weigh, compressive strength, water content and neutron macroscopic cross section of a new type of concrete shields made from egyptian ilmenite and serpentine ores when heated for long period at temperatures up to 600 degree C. Results show that the unit weight of the cure concrete has a value of 2.98 Ton/M3 and decreases with increasing temperature, while the compressive strength reaches a maximum value of 19 Ton/M2 at 100 degree C. The differential thermal analysis (D.T.A.) of this concrete shows three endothermic peaks at 100 degree C, 48 degree C and 740 degree C. Also, the thermogravimetry analysis (T.G.A.) shows that the cure concrete retains about 11% water content of the total sample weigh and still retains 4.5% of its initial value when heated for long period at 600 degree C. Results also show that the neutron macroscopic cross section (for neutrons of energies < 1 MeV) of the ilmenite-serpentine heat resistant concrete decreases to 18.6% of its initial value after heating to 600 degree C

  9. Sustainable, heat-resistant and flame-retardant cellulose-based composite separator for high-performance lithium ion battery.

    Zhang, Jianjun; Yue, Liping; Kong, Qingshan; Liu, Zhihong; Zhou, Xinhong; Zhang, Chuanjian; Xu, Quan; Zhang, Bo; Ding, Guoliang; Qin, Bingsheng; Duan, Yulong; Wang, Qingfu; Yao, Jianhua; Cui, Guanglei; Chen, Liquan

    2014-01-01

    A sustainable, heat-resistant and flame-retardant cellulose-based composite nonwoven has been successfully fabricated and explored its potential application for promising separator of high-performance lithium ion battery. It was demonstrated that this flame-retardant cellulose-based composite separator possessed good flame retardancy, superior heat tolerance and proper mechanical strength. As compared to the commercialized polypropylene (PP) separator, such composite separator presented improved electrolyte uptake, better interface stability and enhanced ionic conductivity. In addition, the lithium cobalt oxide (LiCoO2)/graphite cell using this composite separator exhibited better rate capability and cycling retention than that for PP separator owing to its facile ion transport and excellent interfacial compatibility. Furthermore, the lithium iron phosphate (LiFePO4)/lithium cell with such composite separator delivered stable cycling performance and thermal dimensional stability even at an elevated temperature of 120C. All these fascinating characteristics would boost the application of this composite separator for high-performance lithium ion battery. PMID:24488228

  10. Effect of normalizing temperature on the strength of 9Cr–3W–3Co martensitic heat resistant steel

    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

  11. Effects of cerium microalloying on the structure and properties of heat resistant steel of 4Kh4VMFS

    It is attempted to follow the peculiarity of structural-physical changes under high-temperature heating in subcritical region and on this base possible mechanisms of cerium effect on heat resistance increase of instrumental compos ition (0.42% C; 0.80% Si; 0.37% Mn; 4.0% Cr; 0.98% W; 1.55% Mo; 1.22% V; 0.01% Ca including the variant with 0.08% Ce) is chosen for investigation. Cerium microalloying is shown to result in advisability of precipitations in the 400-500 deg C tempering temperature range of cementite carbides on the boundaries and in the centre of matrix grains that is associated with liquating inhomogeneity by cerium and carbon. The noted inhomogeneity is levelled with the increase of tempering temperature above 500 deg C. Cerium inhibits the process of Fesub(α)-solid solution decomposition under tempering and its depletion by tungsten and molybdenum. Cerium microalloying of 4Kh4VMFS steel restrains carbide phase coagulation at high temperatures of tempering, it promotes inhibiting the recrystallization processes, assures increased fracture toughness

  12. Influence of salicylic and succinic acids on antioxidant enzymes activity, heat resistance and productivity of Panicum miliaceum L.

    Miroshnichenko N.N.

    2011-05-01

    Full Text Available The influence of treatment of millet (Panicum miliaceum L. seeds with the solutions of salicylic and succinic acids on the heat resistance of plantlets and activity of antioxidant enzymes – superoxide dismutase (SOD, catalase and peroxidase – in them have been investigated. In the micro-field experiment the influence of these acids on the millet yield was estimated. The action of salicylic (10 μM and succinic (1 mM acids caused the increase of plantlets resistance to the damaging heating that expressed in the rise of relative quantity of survived plantlets in 5 days after heating at the temperature of 47°С and in the reduced content of lipid peroxidation product malonic dialdehyde during the poststress period. The increase of activity of SOD, catalase and peroxidase took place in millet plantlets under the influence of salicylic and succinic acids. The increase of productivity of millet grain under the action of salicylic and succinic acids on 13,3-52,0 and 6,4-38,8% respectively depending on weather conditions in the field experiments was noted.

  13. Screening foods for processing-resistant bacterial spores and characterization of a pressure- and heat-resistant Bacillus licheniformis isolate.

    Ahn, Juhee; Balasubramaniam, V M

    2014-06-01

    This study was carried out to isolate pressure- and heat-resistant indicator spores from selected food matrices (black pepper, red pepper, garlic, and potato peel). Food samples were processed under various thermal (90 to 105C) and pressure (700 MPa) combination conditions, and surviving microorganisms were isolated. An isolate from red pepper powder, Bacillus licheniformis, was highly resistant to pressure-thermal treatments. Spores of the isolate in deionized water were subjected to the combination treatments of pressure (0.1 to 700 MPa) and heat (90 to 121C). Compared with the thermal treatment, the combined pressure-thermal treatments considerably reduced the numbers of B. licheniformis spores to less than 1.0 log CFU/g at 700 MPa plus 105C and at 300 to 700 MPa plus 121C. The inactivation kinetic parameters of the isolated B. licheniformis spores were estimated using linear and nonlinear models. Within the range of the experimental conditions tested, the pressure sensitivity (zP) of the spores decreased with increasing temperature (up to 121C), and the temperature sensitivity (zT) was maximum at atmospheric pressure (0.1 MPa). These results will be useful for developing a combined pressure-thermal inactivation kinetics database for various bacterial spores. PMID:24853517

  14. High temperature corrosion of iron-base and nickel-base alloys for hydrogen production apparatus by thermochemical method in H2O+SO3 atmosphere

    Corrosion tests for ten iron-base and nickel-base alloys at 850degC for 1000h in H2O + SO3 atmosphere were carried out to obtain data for selection of candidate container materials in the thermochemical process which produces hydrogen from water by use of iodine and sulfur as circulating materials. The following results were obtained: (1) Oxidation, spallation of corrosion film, uniform corrosion and grain boundary penetration composed of internal oxidation and sulfuration occur in this atmosphere and the corrosion proceeds by grain boundary penetration. (2) SUS304, SUS316 and Hastelloy C276 are inferior in corrosion resistance and SUS329J4L is superior among ten alloys used in this experiment. Alloys such as Alloy 800H and Hastelloy XR show intermediate corrosion resistance. (3) Oxide films of alloys containing iron and chromium are mostly composed of outer iron-oxide and inner chromium-oxide. Sulfur concentrates at scale/metal interfaces and grain boundary penetration portions, and sulfides form. (4) Corrosion in this atmosphere could be expressed using the parabolic law between the grain boundary penetration depth and time. It is considered that causes of the apparently observed parabolic law were a high concentration of SO3 and change of the gas composition caused by catalytic action of the corrosion film formed with the progress of corrosion. (author)

  15. Development of powder metallurgy Al alloys for high temperature aircraft structural applications, phase 2

    Chellman, D. J.

    1982-01-01

    In this continuing study, the development of mechanically alloyed heat resistant aluminum alloys for aircraft were studied to develop higher strength targets and higher service temperatures. The use of higher alloy additions to MA Al-Fe-Co alloys, employment of prealloyed starting materials, and higher extrusion temperatures were investigated. While the MA Al-Fe-Co alloys exhibited good retention of strength and ductility properties at elevated temperatures and excellent stability of properties after 1000 hour exposure at elevated temperatures, a sensitivity of this system to low extrusion strain rates adversely affected the level of strength achieved. MA alloys in the Al-Li family showed excellent notched toughness and property stability after long time exposures at elevated temperatures. A loss of Li during processing and the higher extrusion temperature 482 K (900 F) resulted in low mechanical strengths. Subsequent hot and cold working of the MA Al-Li had only a mild influence on properties.

  16. Deposition of CeO 2/YSZ buffer layer on Hastelloy substrates for MOD process of YBa 2Cu 3O 7- x film

    Fuji, Hiroshi; Honjo, Tetsuji; Nakamura, Yuichi; Izumi, Teruo; Takeshi, Araki; Hirabayashi, Izumi; Shiohara, Yuh; Iijima, Yasuhiro; Takeda, Kaoru

    2001-08-01

    Trifluoroacetate metalorganic deposition (TFA-MOD) process is expected as a low cost process for mass production of coated conductors because it is a non-vacuum process. In order to apply the technique to fabrication of coated conductors, suitable buffer layers have to be considered to achieve a high orientation of superconducting layer and prevention of the reaction with metal substrate. The combination of CeO 2 on IBAD-YSZ is considered as an effective buffer for TFA-MOD process expecting to satisfy a high acid resistivity and high crystal grain alignment. The CeO 2 buffer layer was deposited on IBAD-YSZ/Hastelloy substrates by RF magnetron sputtering. From XRD analysis, the CeO 2 buffer layer showed very good in-plane alignment on YSZ-IBAD buffer layer. In a holding time of 1 h, the suitable maximum heat treatment temperature was found to be from 750°C to 775°C for TFA-Y123 on metal substrate. The Jc- B property of Y123 on CeO 2/YSZ/Hastelloy shows the Jc values of 1.4 MA/cm 2 at 77.3 K, 0 T and more than 10 5 A/cm 2 at 77.3 K, 2 T. The high performance under high magnetic field was confirmed.

  17. Evaluation of the same heat Hastelloy XR as the material used for high-temperature components of the High-Temperature Engineering Test Reactor, 2

    A series of tension, Charpy impact and creep tests was carried out on two sorts of plate materials with 15 mm and 60 mm in thickness obtained from typical one of 30 heats of Hastelloy XR manufactured as the component material of the High-Temperature Engineering Test Reactor (HTTR). Creep test temperatures were 850, 900, 950 and 1000degC, and the maximum creep test time was 3371.4 h. The results obtained are as follows: (1) Both of plate materials tested exhibit acceptable tensile strength and tensile ductility as the structural material of the high-temperature components of the HTTR. (2) The plate material with 15 mm in thickness exhibits enough toughness, while toughness of the plate material with 60 mm in thickness is inferior to that of the plate material with 15 mm in thickness. (3) Both of plate materials tested possess the creep rupture strength beyond not only the expected minimum stress-to-rupture values, SR, but also the expected mean stress-to-rupture values of the material strength standards of Hastelloy XR. The materials also possess enough creep rupture ductility. (author)

  18. Modifying effect of extremal temperature depending on the organism adaptation to this factor on the effect of radiation. 2. Analysis of the potential damages using heat resistance

    It is shown, that the effect of high temperature within the range of 33, 35, 37 and 38 deg C after irradiation (X-rays 3000r) increases the radiation effect, manifesting itself in the loss of X-chromosome of Kanton-C line flies, not adapted to high temperature. It takes place at the expense of reparation process depression and the increase of probability of potential damage realization. The effect on the flies of T-32 line, adapted to high temperature (32 deg C) turned non-effective at the temperature of 33 and 35 deg C. Heat-resistance of reparation ferments in this line is supposed to be higher. The temperature of 37 and 38 deg C has been effective for heat-resistant lines as well as for other lines

  19. The effect of miced plasticizer on radiation crosslinking of wire and cable materials for heat resistant 105 deg C polyvinyl chloride

    To prepare 105 deg C heat resistant PVC wire and cable, the ester of trimellitic acid are generally used by its plasticizer, for example TOTM and NODTM etc., but the price of this kind of plasticizer is higher. For the sake of depression of quantity of TOTM, in present work, the effect of mixer of TOTM and ESBO (epoxide soyabean oil) on the properties of radiation crosslinked wire and cable for 105 deg C heat resistant PVC has been studied. From mechanical, electric properties and thermal stability of wire and cable with different ratio TOTM/ESBO, it may be known that the radiation crosslinked wire and cable will possess better synthetic properties, when the usable quantity of ESBO is an qppropriate amount

  20. Elevated levels of 70,000 dalton heat shock protein in transiently thermotolerant Chinese hamster fibroblasts and in their stable heat resistant variants

    The function of one or more shock proteins (HSPs) may be to confer protection of cells against thermal damage. The quantitative relationship between heat sensitivity and concentration of several HSPs was examined in thermotolerant Chinese hamster HA-1 cells and in their heat-resistant variants. Low molecular weight HSPs (22-27 kd) showed no correlation with cell survival. The best correlation was found between concentration of 70 kd HSP and the logarithm of cell survival. There was no difference between the HSP 70 induced by heat shock and that present in a constitutive form. The 70 kd HSP may actually confer heat resistance on cells, but in any case HSP 70 appeared to be the best predictor of heat response

  1. Effect of creep deformation on the microstructural evolution of 11CrMoVNb heat resistant steel

    Lee, K.H.; Park, D.B. [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Kwun, S.I.; Huh, J.Y. [Department of Materials Science and Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Suh, J.Y.; Shim, J.H. [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Jung, W.S., E-mail: wsjung@kist.re.kr [High Temperature Energy Materials Research Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of)

    2012-02-28

    Highlights: Black-Right-Pointing-Pointer The coarsening rate of the precipitates was accelerated by applied stress. Black-Right-Pointing-Pointer The coalescence of martensite laths was accelerated by applied stress. Black-Right-Pointing-Pointer The Laves phase and Z-phase were not observed after creep. Black-Right-Pointing-Pointer The predicted size of MX precipitates by MatCalc agreed well with measured size. - Abstract: The effect of creep deformation on the microstructural evolution of an 11CrMoVNb ferritic heat resistant steel during high temperature creep tests was investigated. The creep test was performed within a temperatures range from 593 to 621 Degree-Sign C under different stress levels. For the detailed understanding of precipitate coarsening behavior, transmission electron microscopy (TEM) was used to analyze thin foils and replica films obtained from the crept specimens. The major precipitates were found to be M{sub 23}C{sub 6}, MX and Cr{sub 2}N phases and there was no change in precipitation sequence during creep. Coarsening behavior of the precipitates and growth behavior of martensite laths of the crept specimens were carefully examined in both regions of the grip and gage parts of the specimens in order to identify the effect of creep deformation. On the whole, precipitate size increased with increasing creep rupture time. On the other hand, precipitate coarsening and martensite lath widening were pronounced in the gage part compared to those in the grip part. This suggests that the creep deformation accelerates the rates of precipitate coarsening and martensite lath widening.

  2. Heat-resistance of 06Kh16N15Mo3B stainless steel with hydroxide impurity at 973 K

    Stainless steels of class 316 are structural materials for sodium-cooled fast reactors. Up to 973 K reactor-grade sodium causes virtually no change in the mechanical properties of stabilized and unstabilized 316 stainless steels. Sodium contaminated with oxygen (up to 300 ppm) also does not cause changes in the mechanical properties of this steel up to 973 K. The effect of sodium with an increased carbon content on steel of this class slightly increases the heat resistance and reduces the plasticity. No data are available, however, on the effect that sodium with hydroxide has on the mechanical properties of steel at temperatures up to 973 K. It is desirable, therefore, to study the effect of sodium with hydroxide impurity on the long-term strength and creep of 06Kh16N15Mo3B stainless steel at 973 K. It was found that the effect of sodium with 8% hydroxide on 06Kh16N15Mo3B steel under a static load at 973 K causes virtually no loss of long-term strength or increase in the creep rate up to the third stage of creep. In the third stage the creep rate increases abruptly and the time to fracture is reduced in comparison with the case in tests in pure sodium. This effect is probably due to the accelerated development of microcracks in the steel, which reach a critical size, as a result of the decrease in surface energy because of the adsorption of the atoms of the medium

  3. Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System

    Panek, Jacek; Frąc, Magdalena; Bilińska-Wielgus, Nina

    2016-01-01

    Spoilage of heat processed food and beverage by heat resistant fungi (HRF) is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in...

  4. Porous membrane with high curvature, three-dimensional heat-resistance skeleton: a new and practical separator candidate for high safety lithium ion battery

    Junli Shi; Yonggao Xia; Zhizhang Yuan; Huasheng Hu; Xianfeng Li; Huamin Zhang; Zhaoping Liu

    2015-01-01

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural chara...

  5. Devising and producing nickelless and economically alloyed nickel steels for boiler equipment

    Ryabchenkov, A.V.; Kuznetsov, E.V.; Chechel' , L.A.; Parshin, Yu.N.

    1987-11-01

    On the basis of theoretical investigations of the corrosive effect of the combustion products of natural organic fuel on structural materials, compositions of the chromium-manganese steels economically alloyed with nickel and also of nickelless chromium steels were devised at the Scientific and Production Association TsNIITMash; under the conditions of combustion of aggressive fuel, these steels are more heat resistant than ordinary chrome-nickel austenitic steels.

  6. Efficiency of two-stage ion-plasma technology of production of alloyed diffusion aluminide coatings on the Ni-based superalloys

    A consideration is given to diffusion ion-plasma coatings produced according to a two-stage technology with the use of three nickel alloys of a Ni-Cr-Al-Y system doped with tantalum, tungsten, rhenium and two aluminium alloys doped with nickel, yttrium, silicon. The structure, chemical and phase compositions of coatings on heat resistant nickel base alloys ZhS6U, ZhS26, ZhS32 are investigated depending on initial alloy layer thickness. It is shown that the two-stage coating technology permits a considerable enhancement of operational properties of the coatings

  7. Effect of carbon and niobium on the microstructure and impact toughness of a high silicon 12% Cr ferritic/martensitic heat resistant steel

    In order to guide the design of 912% Cr ferritic/martensitic (F/M) heat resistant steels appropriate for use in accelerator-driven system, the impact toughness and behavior of precipitation of a 12% Cr F/M heat resistant steel containing high C and Si concentrations have been investigated. Particular focus has been given to the interaction of carbon and carbonitride-forming element. Because of the presence of primary NbC and a large amount of M23C6, the impact toughness of the investigated steel was much lower than that of the commercial 912% Cr F/M heat resistant steels. The primary NbC crystallizes directly from liquid metal when the Nb concentration is higher than a critical value. The critical value of Nb decreases with increase in the carbon concentration. In addition, the higher content and faster precipitation kinetics of M23C6 in the investigated steel during the tempering heat treatment also lowers the impact toughness

  8. Effect of carbon and niobium on the microstructure and impact toughness of a high silicon 12% Cr ferritic/martensitic heat resistant steel

    Ye, Zhongfei [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Wang, Pei, E-mail: pwang@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Li, Dianzhong [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Zhang, Yutuo [Shenyang Ligong University, 6 Nanping Road, Shenyang 110159 (China); Li, Yiyi [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2014-10-20

    In order to guide the design of 9–12% Cr ferritic/martensitic (F/M) heat resistant steels appropriate for use in accelerator-driven system, the impact toughness and behavior of precipitation of a 12% Cr F/M heat resistant steel containing high C and Si concentrations have been investigated. Particular focus has been given to the interaction of carbon and carbonitride-forming element. Because of the presence of primary NbC and a large amount of M{sub 23}C{sub 6}, the impact toughness of the investigated steel was much lower than that of the commercial 9–12% Cr F/M heat resistant steels. The primary NbC crystallizes directly from liquid metal when the Nb concentration is higher than a critical value. The critical value of Nb decreases with increase in the carbon concentration. In addition, the higher content and faster precipitation kinetics of M{sub 23}C{sub 6} in the investigated steel during the tempering heat treatment also lowers the impact toughness.

  9. [Superplastic forming of titanium alloy denture base].

    Okuno, O; Nakano, T; Hamanaka, H; Miura, I; Ito, M; Ai, M; Okada, M

    1989-03-01

    Ti-6Al-4V alloy has both excellent biocompatibility and superior mechanical properties. This Ti-6Al-4V can be deformed greatly and easily at the superplastic temperature of 800 degrees C to 900 degrees C. The superplastic forming of Ti-6Al-4V was made to apply to fabrication of denture base. Almost the same procedure as for dental casting mold was employed in producing the superplastic forming die by the improved phosphate bonded investment. In the pressure vessel of heat resistant alloy, Ti-6Al-4V plate was formed superplastically on the die by argon gas pressure at 850 degrees C. The fit of superplactic forming Ti-6Al-4V denture base was better than that of casting Co-Cr alloy denture bases. The Ti-6Al-4V alloy might react a little with the die. Because micro Vikers hardness of the cross-section did not go up too much near the surfaces. Even just after being formed, the surfaces were much smoother than that of Co-Cr alloy casting. The tensile strength and yield strength of superplastic forming Ti-6Al-4V were higher than those of Co-Cr castings. The elongation was about 10%. These results show that superplastic forming of Ti-6Al-4V would be suitable for a denture base. PMID:2603084

  10. Influence of alloying elements on the chlorination behavior of nickel- and iron-based alloys

    A wide range of commercial heat-resistant alloys has been tested in a H2 + 10% HCl environment at 550 C, 650 C, 680 C, 750 C and 850 C. The tests were carried out using a 24 h cycle with a total test time of up to 1,056 H. Weight change was determined, and the average value for three specimens per alloy and temperature plotted versus time, followed by a metallographic examination of the depth of corrosion. By a statistical evaluation of the data generated, it was possible to describe the weight change and penetration depth of all the alloys under examination as a function of the concentration of their main alloying elements and test temperature. According to these results, alloying elements nickel and molybdenum have a beneficial influence on chlorination resistance, whereas silicon and titanium are detrimental. Increased temperature always resulted in enhance corrosion. Only Ni, Ni-Mo, and Ni-Cr-Mo alloys show acceptable resistance for temperatures up to 850 C

  11. Carbon corrosion of alloys at high temperature

    D.J., Young; J., Zhang.

    2013-02-01

    Full Text Available Alloys used at high temperature must resist both creep and corrosion. Design for corrosion resistance is based on the formation of a slow-growing, protective oxide scale by selective oxidation of an appropriate alloy component, usually chromium or aluminium. A successful scale will exclude other cor [...] rodents, notably carbon, which can otherwise cause extremely rapid corrosion at high temperatures. Selective oxidation of an alloy component necessarily lowers the concentration of that metal in the alloy subsurface region. Under thermal cycling conditions, mechanical damage to the scale leads to renewed oxide growth and accelerated alloy depletion. Eventually, a point is reached where diffusion of a corrodent into the alloy becomes competitive with the outward diffusion of alloy metal to repair the protective scale. Two examples of alloy failure by carbon attack are considered. In the steam cracking (pyrolysis) process, centrifugally cast tubes of heat-resisting alloy are exposed to a gas stream of hydrocarbon and steam, at a carbon activity of unity. Formation and repair of the surface chromia scale causes alloy depletion, Kirkendall void formation, and subsequent internal precipitation of chromium-rich carbides. Their formation makes chromia scale formation much more difficult, and generates internal stress. Eventually, the tubes fail by creep rupture. In other processes (e.g. steam reforming, heat treatment), synthesis gases are supersaturated with carbon at intermediate temperatures. Once the alloy's protective scale is breached, carbon attacks the depleted substrate. In the case of ferritic alloys, it forms a surface scale of Fe3C. As this scale thickens, the supersaturated carbon precipitates as graphite within its outer regions. The resulting volume expansion causes disintegration of the cementite in a process known as metal dusting. In the case of austenitic alloys, no metal carbide is formed. Instead, carbon dissolves in the depleted metal to diffuse inward and precipitate as graphite within the metal matrix. Again, volume expansion causes disintegration of the alloy, and metal dusting results. Dusting occurs at an extraordinarily rapid rate, and leads to failure by section loss or even penetration.

  12. Attack of high-strength, oxidation-resistant alloys during in-can melting of simulated waste glasses

    The restistance of candidate canister alloys to penetration under the most severe conditions expected during in-can melting was directly proportional to the chromium content of the alloy, and inversely proportional to the Na2O content of the glass melt. Specimens were exposed for 24 hours, which is the time required for in-can melting full-size waste-glass forms based on tests carried out at Pacific Northwest Laboratories (PNL) and at SRL. The penetration resistance to Frit 211 at 11500C for 24 hours of most alloys tested was satisfactory. The amount of penetration would not affect the integrity of the waste form. Inconel 625, Hastelloy X, and Inconel 601 were penetrated 100 mils by a glass composed of 65 wt % Frit 21 and 35 wt % composite sludge (with uranium) at 11500C for only 7 hours. This amount of penetration of an in-can melting canister would not be satisfactory. 12 figures

  13. Study of nucleation, growth and coarsening of precipitates in a novel 9%Cr heat resistant steel: Experimental and modeling

    Nucleation, growth and coarsening of three different precipitates (NbC, M23C6 and V(C,N)) in a novel 9%Cr heat resistant steel designed by the authors were investigated. The microstructure evolution after tempering (780 °C/2 h) and after creep (650 °C/100 MPa) was characterized using transmission electron microscopy in the scanning mode (STEM). Thermodynamic and kinetic modeling was carried out using the softwares Thermo-Calc, DICTRA and TC-PRISMA. The Thermo-Calc software predicted formation of NbC, V(C,N) and M23C6 carbides at the tempering temperature of 780 °C. STEM investigations revealed that M23C6 precipitated on prior austenite grain boundaries and lath or block boundaries whereas NbC and V(C,N) were located within sub-grains. Simulations by TC-PRISMA showed that M23C6, NbC and V(C,N) particles nucleation begins as soon as the tempering treatment starts and it is completed in a very short time, reaching the equilibrium volume fraction after 40 s for M23C6, 100 s for NbC and 80 s for V(C,N). Best agreement between simulations and experimental investigations was found for low interfacial energy values of 0.1 J m−2. Both STEM measurements as well as DICTRA simulations indicate very low coarsening rate for both kind of precipitates. Creep tests up to 4000–5000 h suggest that this special combination of NbC, V(C,N) and M23C6 may provide increased pinning of dislocations reducing boundary migration therefore enhancing creep strength. - Highlights: • Nucleation, growth and coarsening of NbC and M23C6 precipitates were investigated. • The microstructure was characterized using transmission electron microscopy (STEM). • Modeling was carried out using the softwares Thermo-Calc, DICTRA and TC-PRISMA. • M23C6 and NbC nucleation begins as soon as the solution treatmentinitiates. • Best agreement modeling/experiments was found for low interfacial energy values of 0.1 J m−2

  14. Study of ν'-phase dissolution aging resisting nickel alloys

    Dissolution processes of strengthening ν'-phase in the KhN77TYuR and KhN70VMTYu commercial heat-resisting ageing alloys have been investigated by the method of contact difference of potentiats (CDP). Graphs were plotted and empirical dependences of CDP values and atloy hardness on the time of their hold-up at overheating temperatures were found. Decrease of ν'-phase content in alloys results in CDP increase. Intensity of CDP change in the above alloys during their heating above temperatures of phase transformations depends on the quantity and stability of ν'-phase. The CDP method is recommended as a method of nondestructive testing to reveal the overheating of the avobove aitoys

  15. Thermodynamic analysis of metals and alloys interaction with nitrogen oxides

    Interaction thermodynamic analysis of Fe, Cr, Ni, Mo, Mn, Ti (taking into account thermodynamic activity in steels and alloys) and atmospheres, containing different quantities of NsOk (N2O4, NO2, NO) is conducted. Thermodynamic characteristic analysis of nitrogen oxide interaction with metals allows one to give a number of recommendations, concerning metal protection against corrosion in gaseous atmospheres, containing NsO=k: utilization of pure metals or doped steels and alloys as structural materials, working in contact with NsOk, does not substantially change the picture of the material thermodynamic resistance: any of the materials under consideration is thermodynamically reactive at PNs-Ok >> 10-1 MPa. However, steels and alloys, containing Cr, Si may produce heat-resistant oxidonitride surface films. Corrosion resistance of a metal product, containing with NsOk, can be increased both by preliminary nitration and oxidation of its surface

  16. Electrochemical corrosion studies on metallic packaging materials for high-level waste. Behavior of Hastelloy C 4 in quinary brine and 1 M NaCl solutions

    The temperature dependent current density - potential behavior of Hastelloy C 4 in Q-brine is determined for T=250C and T=900C. The material gets passivated instantaneously. The stability of the protecting passivated layer is greatly reduced at T >= 550C to 600C. Some of the specimens differ greatly from each other in their behavior which is attributed to inhomogeneities in the structure and composition of the materials. The results obtained from the electrochemical corrosion studies make evident a clear effectiveness of various impurities and radiolytic products potentially occurring in brines produced in an accident. These impurities and radiolytic products cause a destruction of this material through local corrosion depending on their concentration and time. (orig./PW)

  17. 9-12% Cr heat resistant steels : alloy design, TEM characterisation of microstructure evolution and creep response at 650oC

    Rojas Jara, David

    2011-01-01

    Diese Arbeit handelt sich um die Legierungsentwicklung von 9-12%Cr kriechbeständigen Stählen für Kraftwerkskomponente. Computerunterstützte Thermodynamik wurde für das Design der neuen Legierungen verwendet, vor allen der Einfluss verschiedener Legierungselementen auf die Gefügebildung. Insbesondere die Zusammenhänge zwischen Mikrostrukturentwicklung und Kriechverhalten bei 650oC und 100 MPa wurden untersucht. Das Gefüge (unter anderen Ausscheidungen, Versetzungsdichte, Subkörn...

  18. Cast heat-resistant austenitic steel with improved temperature creep properties and balanced alloying element additions and methodology for development of the same

    Pankiw, Roman I; Muralidharan, Govindrarajan; Sikka, Vinod Kumar; Maziasz, Philip J

    2012-11-27

    The present invention addresses the need for new austenitic steel compositions with higher creep strength and higher upper temperatures. The new austenitic steel compositions retain desirable phases, such as austenite, M.sub.23C.sub.6, and MC in its microstructure to higher temperatures. The present invention also discloses a methodology for the development of new austenitic steel compositions with higher creep strength and higher upper temperatures.

  19. A study of the formation of tungsten-carbide surface alloyed layer on high carbon steel by Co2 laser

    In order to improve the wear- and heat-resistance of high carbon steel, a surface alloyed layer was created on a SK-3 steel with tungsten carbide by irradiation of Co2 layser. The object of this work was to investigate the effects of powder size and coating thickness of tungsten carbide, and the heat treatment on the mechanical properties of the laser surface alloyed layser. The results showed that tungsten carbide was distributed homogeneously throughout the alloyed layser. The amount of tungsten and hardness in alloyed layser were dependent upon the powder size and the thickness of coated layer. When alloyed layser was formed by overlapping laser tracks, and microhardness of this region decreased slightly. When the specimen was heat treated, the microhardness tended to increase depending upon the amount of tungsten in the alloyed layer. (Author)

  20. Constitutive equations for the creep behaviour of nickel-base alloys for HTR components in the temperature range 1023-1273 K

    The applicability and modification of constitutive equations for describing the creep and relaxation behaviour of the nickel-base alloys INCONEL 617, NIMONIC 86 and HASTELLOY S have been investigated. Creep tests at stresses in range 10-150 MPa and temperatures in the range 1023-1273 K were carried out for the three alloys and in addition for INCONEL 617 and HASTELLOY S relaxation and stress dip tests in the stress range 10-170 MPa and temperature range 1073-1223 K were performed. The fitting of various creep equations to the measured creep curves showed that the best description of the primary and secondary creep regions was given by the equation formulated by Li. Under the experimental conditions used, dislocation climb was the dominant deformation mechanism. Using the internal stress concept to account for the resistance to deformation, a Norton creep law exponent of 3 for INCONEL 617 was derived which is in agreement with the value calculated by Weertman for dislocation climb controlled screep in solid solutions. For HASTELLOY S a lower value was observed. The dependence of the internal stress in the temperature and stress range on creep strain, applied stress, deformation prior to testing, temperature and alloy composition was determined. Relaxation and stress dip tests showed two separate time dependent relationships for the reduction of stress or anelastic backstrain. A rapid decrease at the start of the test due to back glide of dislocations and a much slower decrease associated with recovery were observed. Calculation of the stress relaxation behaviour based on the Norton creep law alone led to a time dependence which was not reflected in the experimental results. However, taking into account the internal stress which decreases during the relaxation test due to recovery processes, it was possible to describe satisfactorily the experimentally determined relaxation curves. (orig.)

  1. Effect of surface protection measures on very high strength gas turbine materials. Pt. 2. Effect of structure. [Base materials: Alloy-IN-738 LC, Udimet 520, Alloy-IN-792, Alloy-IN-100, Alloy CMSX-2, Steel X53 CrMnNiN 21 9; coating material: Cr, PtAl, CrAl, NiCoCrAlY, CoNiCrAlY, NiCr

    Sachova, E.; Hougardy, H.

    1987-01-01

    Corrosion protection coatings can have an effect on the creep behaviour of heat-resistant alloys by two mechanisms: 1. If the failure of uncoated samples is mainly determined by progressive corrosion on the surface, the time until fracture can be extended by applying a protective coating. 2. Due to heat treatment which is connected with applying the protective coating and by diffusion processes on the boundary of the protective coating during creep stress, the structure of the basic material may be changed and therefore the creep behaviour may be affected. The research project is intended to check to what extent the creep behaviour of heat-resistant alloys is changed by applying protective coatings, according to points 1 and 2 above. The metallographic test should clear up which of the above mechanisms was effective. Only broken samples are available for the total observation of structure. (orig./IHOE).

  2. ИОННО-ПЛАЗМЕННАЯ ТЕХНОЛОГИЯ ФОРМИРОВАНИЯ ПОКРЫТИЙ НА ЛОПАТКАХ ТУРБИНЫ ГТД ИЗ ЖАРОСТОЙКИХ НИКЕЛЕВЫХ СПЛАВОВ Ion-plasma technology of deposition heat-resistant coatings for GTE turbine blades from resistant nickel alloys

    А. М. Смыслов

    2012-10-01

    Full Text Available Рассматривается возможность получения нанослойных жаростойких покрытий с использованием технологий, основанных на высокоэнергетических ионно-имплантационных и ионно-плазменных методах защитно-упрочняющей обработки и нанесения покрытий. Приводятся результаты исследования жаростойкости и предела выносливости деталей из никелевых жаропрочных сплавов.The possibility of obtaining heat-resistant coatings using “nano-technology” based on high-energy ion-implantation and ion-plasma methods, protective and strengthening treatment and coating. The results of the study the heat resistance and fatigue strength of parts made of nickel-base superalloys.

  3. The abnormal segregation behavior of solutes under tensile stress and its effect on carbide reactions in 2.25Cr–1.5W heat-resistant steels

    The phosphorus segregation concentration at grain boundary/carbide interfaces of 2.25Cr–1.5W heat-resistant steels under tensile stress shows a broad convex profile in a log time versus segregation concentration plot. The decrease in phosphorus segregation concentration after the maximum in the convex profile is due to the formation of new equilibrium MC carbides on the surface of the pre-formed M23C6 carbides and its partitioning effect of the phosphorus segregated at the M23C6 carbide interface to the interface of the new MC carbides

  4. Application of high nickel alloys in the field of experience within corrosion resistance protection in flue gas desulphurization plants absorbers

    Absorbers are the main components of flue gas desulphurization plants for 360 MW power-generating units in Belchatow Power Plant. The whole plant operating cycle and its service life depend on the type of materials applied for corrosion resistance lining of various absorber zones. RAFAKO S.A. activities within this field are focused on the extension of FGD plant service life via implementation of technology of lining the cylindrical part of absorber with 0,5 - 1,6 mm thickness sheets made of Hastelloy type alloys of C-22 and C-2000 grade. The experiment carried out on Hastelloy C-22 and C-2000 alloy grades enabled the assessment of corrosion resistance properties of base material, lining plates, weld joints and HAZ. The paper contains the results of weld joints and HAZ structure assessment, weld joints corrosion resistance characteristics, results of corrosion products examinations as well as requirements and recommendations concerning the execution of weld joints, lining steel surface preparation for welding, etc. (authors)

  5. Study of superficial films and of electrochemical behaviour of some nickel base alloys and titanium base alloys in solution representation of granitic, argillaceous and salted ground waters

    The corrosion behaviour of the stainless steels 304, 316 Ti, 25Cr-20Ni-Mo-Ti, nickel base alloys Hastelloy C4, Inconel 625, Incoloy 800, Ti and Ti-0.2% Pd alloy has been studied in the aerated or deaerated solutions at 200C and 900C whose compositions are representative of interstitial ground waters: granitic or clay waters or salt brine. The electrochemical techniques used are voltametry, polarization resistance and complexe impedance measurements. Electrochemical data show the respective influence of the parameters such as temperature, solution composition and dissolved oxygen, addition of soluble species chloride, fluoride, sulfide and carbonates, on which depend the corrosion current density, the passivation and the pitting potential. The inhibition efficiency of carbonate and bicarbonate activities against pitting corrosion is determined. In clay water at 900C, Ti and Ti-Pd show very high passivation aptitude and a broad passive potential range. Alloying Pd increases cathodic overpotential and also transpassive potential. It makes the alloy less sensitive to the temperature effect. Optical Glow Discharge Spectra show three parts in the composition depth profiles of surface films on alloys. XPS and SIMS spectrometry analyses are also carried out. Electron microscopy observation shows that passive films formed on Ti and Ti-Pd alloy have amorphous structure. Analysis of the alloy constituents dissolved in solutions, by radioactivation in neutrons, gives the order of magnitude of the Ni base alloy corrosion rates in various media. It also points out the preferential dissolution of alloying iron and in certain cases of chromium

  6. Effect of vanadium addition on the creep resistance of 18Cr9Ni3CuNbN austenitic stainless heat resistant steel

    Highlights: The first observation of V-rich Z-phase in austenitic stainless steel. Separate precipitation of Nb-rich MX and V-rich Z-phase in Nb and V contained steel. The effect of nanometer sized Z-phase on the improvement of creep strength. The predicted size of MX precipitates by MatCalc agreed well with measured size. -- Abstract: The effect of vanadium addition on the creep property of niobium-containing 18Cr9Ni austenitic heat-resistant steel was studied. After solution treatment, the MX precipitates of vanadium-free steel contained Nb only. On the contrary, high Nb and low V contents were detected from the MX precipitates in the steel with 0.3 wt% of vanadium. Vanadium-rich MX carbo-nitride was not observed in the matrix and at the grain boundaries after solution treatment. The vanadium precipitated as a form of Z-phase during early-stage creep deformation was attributed to the improvement in creep strength at 700 C with applied stress higher than 150 MPa. And metallic Cu precipitates were confirmed in the nanometer scale using TEM and EDS technique. The Cu precipitates are believed to contribute to the strengthening of austenitic heat resistant steel independently. The precipitation behavior is discussed using transmission electron microscopy and thermo-kinetics simulation technique

  7. Investigation of weldability and property changes of high pressure heat-resistant cast stainless steel tubes used in pyrolysis furnaces after a five-year service

    Highlights: → To investigate the weldability and property changes of high pressure heat-resistant cast stainless steel (HP) tubes. → Welding was done by gas-tungsten arc welding (GTAW) process. → Composition of precipitates was characterized by means of SEM and EDS analyses. → The solution treatment was used to recover the properties of tubes. → To investigate mechanical strength of specimens, tensile tests were carried out at room temperature. -- Abstract: High pressure heat-resistant cast stainless steel (HP steel) tubes produced by centrifugal casting are used in petrochemical industries for pyrolysis furnaces. They have appropriate ductility and weldability in as-cast conditions. These steels lose their ductility and weldability after being used in service and, hence, require repair. In the present study, the effect of metallurgical changes on weldability and ductility was investigated. The life span of the studied tubes was 5 years. Using electrodes with a chemical composition close to the base metal analysis, welding was done by gas-tungsten arc welding (GTAW) process. Solution treatment was used to recover the properties of tubes which can be useful, depending on metallurgical changes.

  8. ??????? ???????????????????? ????????? ?? ?????? ? ????????? ???????????? ???????? ?? ???????????????? ??????????? ?????????? ?????? HIGH-TEMPERATURE OXIDATION INFLUENCE ON COMPOSITION AND STRUC-TURE OF ALUMINIDE COATING ON ION IMPLANTED SURFACE OF NICKEL ALLOY

    ?. ?. ?????

    2013-01-01

    Full Text Available ??????????? ??????? ???????????????????? ????????? ?? ?????? ? ????????? ????????-??????????? ???????? ????-11, ??????????? ?? ???????? ?? ?????? ???-7?, ???????????????? ?????? ????????. ??????? ????????????????? ????????? ? ???????? ? ?????????? ?????????? ???????? ??? ??????????? 850 ??, ???????? ??????????? ????? ?????????? ????????????? ????????? ? ?????????????????? ????????? ????????. ???????? ???????????? ????????????? ?????? ??????????? ??? ??????? ?????????????? ?????????? ??????????? ?????????? ?????? ??? ????????-?????????? ????????, ?????????????? ????????? ????????????? ??????????? ??????.The paper discusses the influence of high-temperature oxidation on composition and structure of vacuum-plasma coating VSDP-11 deposited on TsNK-7P alloy substrate implanted with ytterbium ions. The elements redistribution in the coating after exposition at 850 oC was studied and the interdependence between the elements redistribution and the life cycle of the protective coating was established. The ion implantation benefits resulting in the increase of the alloy surface heat resistance were shown for the additional nickel alloy surface treatment for the purpose of vacuum-plasma coating deposition.

  9. Spray pyrolysis of MgO templates on Hastelloy C276 and 310-austenitic stainless steel substrates for Y Ba2Cu3O7 (YBCO) deposition by pulsed laser deposition

    MgO thin films were deposited on Hastelloy C276 (HC) and 310 austenitic stainless steel by the spray pyrolysis technique, using magnesium nitrate and magnesium acetate as precursors. Thermogravimetrical analysis of the decomposition of the precursors was used to provide a guideline temperature for the thin film deposition. It was suggested that an amorphous MgO thin film was deposited on both 310-stainless steel and Hastelloy C-276 when using low concentration of the magnesium nitrate precursor. Higher concentrations were needed to obtain (200) oriented MgO films on C276. However, 310-stainless steel was found to not be a suitable substrate for MgO thin film deposition due to surface instability. A (200) oriented MgO thin film was grown on Hastelloy C276 using a magnesium acetate precursor at a much lower concentration compared to the nitrate precursor. The characterization of the thin films was done using scanning electron microscopy, x-ray photoelectron spectroscopy, atomic force microscopy, x-ray diffraction 2?-scans, rocking curves (?-scans), and pole figure measurements. MgO was found to have a very weak in-plane texture.

  10. Phase analysis of high-temperature alloys for nuclear application by interference layer metallography

    Heat-resistant metallic materials for use in hightemperature gas-cooled reactors are nickel- or ironbase, solid-solution-strengthened, or age-hardened alloys. To control the material behavior and to adapt it to realistic load conditions, they have to be tested and characterized. During recent years, interference layer metallography has become an independent characterization procedure as well as an outstanding method for sample preparation for the application of quantitative image analysis to these refractory alloys. The special problems of characterization of nickel- and iron-base alloys that can now be solved by interference layer metallography and its physical backround are reported. Chromatic contrasting and the subsequent phase analysis by way of the example of three common alloys are discussed. Finally, the optimization of interference layer metallography for application in quantitative image analysis is described

  11. High-strength granulated titanium alloys with intermetallide type of hardening

    The alloy VT22, additionally doped with carbon and boron separately and in combination is taken as an example to estimate the influence of dispersity, intermetallic phase (titanium carbides and borides) shape and spatial uniformity on the combination of physical and mechanical properties and the structure of titanium alloys with intermetallic hardening. The alloy rods are manufactured according to as routine (hot deformation of an ingot) so granular (hot isostatic pressing of granules quenched from the melt) technologies. It is shown that the use of the granular technology provides an essential refinement of intermetallic precipitations and improves their spatial uniformity over the structure; this promotes an increase of heat resistance, creep resistance and strength of the alloy

  12. Microstructure and Wear Behavior Of as Cast Al-25mg2si-2cu-2ni Alloy

    1Geetanjali.S.Guggari ,

    2015-09-01

    Full Text Available The remarkable feature of the Aluminium is its low density and ability to withstand corrosion effect due to phenomenon of passivation. Structural components made from Aluminium and its alloys are vital to the aerospace industry and are important in other areas of transportation and structural materials. The oxides and sulphate are useful compounds of Aluminium based on its weight. In this work, an attempt has been made to utilize the combined effect of high cooling rate solidification, unique micro structural evolution mechanism of T6 heat treatment the advantages of hypereutectic Al-Si system alloyed with other elements such as Cu, Fe and Mg. In the present investigation, the binary alloys in the hypereutectic range viz. Al25Mg2Si has been selected as heat resistant Al-Si alloys. A systematic approach has been carried out to explore the micro structural features, mechanical and wear properties of as cast alloys.

  13. Effect of glass-ceramic-processing cycle on the metallurgical properties of candidate alloys for actuator housings

    Weirick, L.J.

    1982-01-01

    This report summarizes the results from an investigation on the effect of a glass ceramic processing cycle on the metallurgical properties of metal candidates for actuator housings. The cycle consists of a 980/sup 0/C sealing step, a 650/sup 0/C crystallization step and a 475/sup 0/C annealing step. These temperatue excursions are within the same temperature regime as annealing and heat treating processes normally employed for metals. Therefore, the effect of the processing cycle on metallurgical properties of microstructure, strength, hardness and ductility were examined. It was found that metal candidates which are single phase or solid solution alloys (such as 21-6-9, Hastelloy C-276 and Inconel 625) were not affected whereas multiphase or precipitation hardened alloys (such as Inconel 718 and Titanium ..beta..-C) were changed by the processing cycle for the glass ceramic.

  14. Research and development of steel and alloy tubes and pipe for nuclear services

    This company has been engaged in the research and development of steel and alloy tubes and pipe for nuclear services, among which the results for four products will be described as follows: (1) Zircaloy tubes for nuclear fuel cladding : the improvement of manufacturing and inspection techniques, the research on improvement in quality of the product (corrosion resistance, texture, hydride precipitation characteristics, mechanical properties, etc.), and irradiation test. (2) Steam generator tubes for a high temperature gas cooled reactor for power generating : high temperature strength, structure change, and oxidation resistance and weldability of Fe-32Ni-20Cr-Ti-Al alloy. (3) Heat resistant alloys for heat exchanger tubes in nuclear steel-making : high temperature strength and oxidation resistance of several kinds of heat resistant alloys, and the introduction of newly installed helium circulating loop system for material testing. (4) Ultra-high strength steel pipe for manufacturing equipment of nuclear fuel material : results of research on improvement in quality of 300ksi and 350ksi grade maraging steels. (auth.)

  15. VANADIUM ALLOYS

    Smith, K.F.; Van Thyne, R.J.

    1959-05-12

    This patent deals with vanadium based ternary alloys useful as fuel element jackets. According to the invention the ternary vanadium alloys, prepared in an arc furnace, contain from 2.5 to 15% by weight titanium and from 0.5 to 10% by weight niobium. Characteristics of these alloys are good thermal conductivity, low neutron capture cross section, good corrosion resistance, good welding and fabricating properties, low expansion coefficient, and high strength.

  16. Porous membrane with high curvature, three-dimensional heat-resistance skeleton: a new and practical separator candidate for high safety lithium ion battery

    Shi, Junli; Xia, Yonggao; Yuan, Zhizhang; Hu, Huasheng; Li, Xianfeng; Zhang, Huamin; Liu, Zhaoping

    2015-02-01

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural characteristics enable the 3D porous skeleton to own several favorable properties, including superior thermal stability, good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection function, etc. which give rise to acceptable battery performances. Considering the simply and cost-effective preparation process, the porous membrane is deemed to be an interesting direction for the future lithium ion battery separator.

  17. Fire and heat resistant laminating resins based on maleimido and citraconimido substituted 1-(diorgano oxyphosphonyl) methyl -2,4- and -2,6- diaminobenzenes

    Mikroyannidis, John A. (inventor); Kourtides, Demetrius A. (inventor)

    1987-01-01

    A class of fire and heat resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-((dialkoxyphosphonyl) methyl)-2-4 and -2,6-diaminobenzenes are described. The polymer precursors are prepared by reacting 1-((diorganooxyphosphonyl) methyl)-2-4 and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-((diorganooxyphosphonyl) methyl)-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarbocylic dianhydride, or aryl diisocyanates, such as methylenebis (4-phenylisocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by differential scanning calorimetry (DSC) and the thermal stability of the polymers is ascertained by thermogravimetric analysis (TGA).

  18. Fire and heat resistant laminating resins based on malemeido and citraconimido substituted 1 -2,4- and -2,6- diaminobenzenes

    Mikroyannidis, John A.; Kourtides, Demetrius A. (02inventors)

    1987-01-01

    A novel class of fire and heat resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-(dialkox phosphonyl) methyl-2-4 and -2,6-diamino benzenes was presented. The polymer precursors are prepared by reacting 1-(diorgano oxyphosphonyl) methyl-2-4- and -2,6-diamino benzenes with maliec anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivaties of 1 (diorgano oxyphosphonyl) methyl -2,4- and -2,6-diamino benzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic dianhydride, or aryl diisocyanates, such as methylene bis(4-phenyl isocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by diferential scanning calorimetry and the thermal stability of the polymers is ascertained by thermogravimetric analysis.

  19. Porous membrane with high curvature, three-dimensional heat-resistance skeleton: a new and practical separator candidate for high safety lithium ion battery

    Shi, Junli; Xia, Yonggao; Yuan, Zhizhang; Hu, Huasheng; Li, Xianfeng; Zhang, Huamin; Liu, Zhaoping

    2015-01-01

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural characteristics enable the 3D porous skeleton to own several favorable properties, including superior thermal stability, good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection function, etc. which give rise to acceptable battery performances. Considering the simply and cost-effective preparation process, the porous membrane is deemed to be an interesting direction for the future lithium ion battery separator. PMID:25653104

  20. Effect of rare earth element yttrium addition on microstructures and properties of a 21Cr-11Ni austenitic heat-resistant stainless steel

    Research highlights: → Applications of Y in 21Cr-11Ni austenitic heat-resistant stainless steel. → Sensible characteristics of microstructure and properties have been observed. → Y has been found be effective in improving hot ductility of 21Cr-11Ni steel. → Inhibitory effect of Y on S segregation to the grain boundary has been observed. -- Abstract: In this comparative study, the microstructure and the mechanical properties of a 21Cr-11Ni austenitic heat-resistant stainless steel with and without addition of rare earth (RE) element yttrium have been investigated. The results show that a number of fine spherical yttrium-rich oxide particles are not uniformly distributed in the matrix of steel with yttrium; instead, they are aligned along the rolling direction. The grains surrounding the alignment are nearly one order of magnitude smaller than those farther away from the alignment. The approximate calculation results indirectly show that the grain refinement may be mainly attributed to the stimulation for nucleation of recrystallization rather than to pinning by particles. Furthermore, the alignment has resulted in significant loss in transverse impact toughness and tensile elongation at room temperature. There is a trough in the hot ductility-temperature curve, which is located between 973 and 1173 K. The ductility trough of steel with yttrium becomes shallow within a certain temperature range, especially around 1073 K, indicating that improvement on hot ductility is achieved by yttrium addition. The results may be attributed to the increase of grain boundary cohesion indicated by the effective improvement on intergranular failure tendency, and the inhibitory effect of yttrium on sulfur segregation to grain boundaries is believed to be an important cause.

  1. Investigation of corrosion and analysis of passive films concerning some nickel alloys and stainless steels in reconstructed geological environments

    This research thesis addresses the corrosion behaviour of materials which might be used for the fabrication of radioactive waste containers. After a bibliographical study on films formed on Fe-Cr-Ni alloys, this research concentrates on passivation and de-passivation phenomena of three nickel-base alloys among the most resistant to corrosion and which also meet processing and economic criteria: Hastelloy C4, Inconel 625 and ZICNDU 25-20. Titanium and Ti-Pd alloy are also studied. Parameters governing pitting corrosion are notably studied. After a recall of knowledge on passive films formed on Fe-Cr-Ni alloys, and a presentation of experimental and technical conditions, the author reports and discussed the results obtained by electrochemical studies, reports the determination of factors governing alloy passivation in geological waters. The influence of some soluble impurities is notably studied. The author reports the analysis by glow discharge optical emission spectrometry to determine the composition of passive films with respect to geological water nature, the immersion duration and the electrode potential. Additional surface analyses are performed by X-ray photoelectron spectrometry (XPS or ESCA) and secondary ion mass spectrometry (SIMS). Finally, the author uses a dosing method by neutron radio-activation of alloy elements to determine dissolution mechanisms

  2. Effect of microalloying and the melting temperature on the properties of ChS70 and ChS88 alloys in the liquid and solid states

    Tyagunov, A. G.; Vyukhin, V. V.; Baryshev, E. E.; Tyagunov, G. V.; Kostina, T. K.

    2015-12-01

    The temperature ranges of the structural transformations associated with the transition of a melt into a homogeneous or microhomogeneous state are determined as a result of a comprehensive study of the physical properties of liquid heat-resistant nickel-based alloys. The effect of microalloying on the melt transition temperature is found. A relation between the state of a melt, crystallization, and a structure and the properties of the solid metal is revealed.

  3. Low-cycle fatigue of two austenitic alloys in hydrogen gas and air at elevated temperatures

    Jaske, C. E.; Rice, R. C.

    1976-01-01

    The low-cycle fatigue resistance of type 347 stainless steel and Hastelloy Alloy X was evaluated in constant-amplitude, strain-controlled fatigue tests conducted under continuous negative strain cycling at a constant strain rate of 0.001 per sec and at total axial strain ranges of 1.5, 3.0, and 5.0 percent in both hydrogen gas and laboratory air environments in the temperature range 538-871 C. Elevated-temperature, compressive-strain hold-time experiments were also conducted. In hydrogen, the cyclic stress-strain behavior of both materials at 538 C was characterized by appreciable cyclic hardening at all strain ranges. At 871 C neither material hardened significantly; in fact, at 5% strain range 347 steel showed continuous cyclic softening until failure. The fatigue resistance of 347 steel was slightly higher than that of Alloy X at all temperatures and strain ranges. Ten-minute compressive hold time experiments at 760 and 871 C resulted in increased fatigue lives for 347 steel and decreased fatigue lives for Alloy X. Both alloys showed slightly lower fatigue resistance in air than in hydrogen. Some fractographic and metallographic results are also given.

  4. Structure and microhardness of alloy VT22 granules additionally doped with carbon and boron

    Aimed to improve heat resistance and strength of titanium base alloys due to carbon and boron additions (up to 0.3%) a study was made into regularities of phase decomposition in VT22 alloy during its rapid quenching from a liquid state on manufacturing granules 100-400 μm in size. Cooling rates on quenching were found to be sufficiently high to prevent precipitating carbides and borides. Subsequent annealing of granules promotes homogeneous precipitation of strengthening phases in the form of titanium carbides and borides, a reasonable amount of carbon and boron remaining in solid solution. An increase in microhardness of annealed granules reaches 20-25% compared to the standard alloy. 6 refs.; 2 figs.; 2 tabs

  5. Bimetallic layered castings alloy steel – grey cast iron

    T. Wróbel

    2011-04-01

    Full Text Available Purpose: In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation.Design/methodology/approach: Prepared bimetallic layered castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and X2CrNiMoN22-5-3. The ratio of thickness between bearing and working part is 8:1. The verification of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches. Moreover was made computer simulation of solidification of bimetallic layered casting in NovaFlow&Solid software.Findings: The results of studies and their analysis show efficiency of new, innovative technology of corrosion and heat resisting layered castings.Research limitations: In further research, authors of this paper are going to application of different material on bearing part of bimetallic layered casting.Practical implications: Prepared bimetallic layered castings according to work out technology can work in conditions, which require from working surface layer of element a high heat resistance and/or corrosion resistance in medium for example of industrial water.Originality/value: The value of this paper resides in new effective method of manufacture of heat resisting castings, mainly for lining of quenching car to coke production

  6. Zirconium alloys

    By adding small amounts of chromium and molybdenum to alloys of Zr-Nb-Sn improved corrosion resistance and lower sensitivity to heat treatment are achieved. The unique features of the new alloys are: a) corrosion resistance comparable with Zircaloy 2 and 4 at low temperature, and comparable with best high temperature resistant zirconium alloys at high temperature; b) a corrosion rate not accelerated by joint action of oxygen and irradiation, and c) good corrosion resistance and mechanical properties not being dependent upon complicated and expensive thermal treatments

  7. Compatibility of graphite with a martensitic-ferritic steel, an austenitic stainless steel and a Ni-base alloy up to 1250 C

    To study the chemical interactions between graphite and a martensitic-ferritic steel (1.4914), an austenitic stainless steel (1.4919; AISI 316), and a Ni-base alloy (Hastelloy X) isothermal reaction experiments were performed in the temperature range between 900 and 1250 C. At higher temperatures a rapid and complete liquefaction of the components occurred as a result of eutectic interactions. The chemical interactions are diffusion-controlled processes and can be described by parabolic rate laws. The reaction behavior of the two steels is very similar. The chemical interactions of the steels with graphite are much faster above 1100 C than those for the Ni-base alloy. Below 1000 C the effect is opposite. (orig.)

  8. Electrical Resistance Alloys and Low-Expansion Alloys

    Kjer, Torben

    The article gives an overview of electrical resistance alloys and alloys with low thermal expansion. The electrical resistance alloys comprise resistance alloys, heating alloys and thermostat alloys. The low expansion alloys comprise alloys with very low expansion coefficients, alloys with very low...... thermoelastic coefficients and age hardenable low expansion alloys....

  9. High frequency fatigue test of IN 718 alloy microstructure and fractography evaluation

    Belan, J.

    2015-01-01

    INCONEL alloy 718 is a high-strength, corrosion-resistant nickel chromium material used at -253 C to 705 C for production of heat resistant parts of aero jet engine mostly. The fatigue test provided on this kind materials were done via low frequency loading up to this time. Nowadays, needs of results at higher volume of loading cycles leads to high frequency loading with aim to shorten testing time. Fatigue test of experimental material was carried out at frequency 20 kHz with stress ration...

  10. Field experience with the use of forged first-stage rotor blades made of EP800 nickel alloy for the GTE-45 gas turbine

    Klypina, A. M.; Trushechkin, V. P.; Chistyakova, L. D.; Kazanskii, D. A.

    2008-02-01

    We present the results from an investigation of the structure, mechanical, and heat-resistant properties the metal of forged first-stage rotor blades of the GTE-45 gas turbine of NPO Turboatom after they had been in operation for a long time at the Yakutsk district power station. It is shown that blades made of this alloy may operate for as long as 60000 h provided that they have been manufactured with good quality. Criteria for the operational reliability of EP800 alloy are developed.

  11. Effect of microstructural evolution on high-temperature strength of 9Cr–3W–3Co martensitic heat resistant steel under different aging conditions

    Evolution of microstructures and high-temperature strength at 650 °C of 9Cr–3W–3Co martensitic heat resistant steel after aging at 650 °C and 700 °C for different time durations have been experimentally investigated using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM) and post-aged tensile tests. The results show that after aging at 650 °C, the high-temperature strength and the microstructures of 9Cr–3W–3Co steel keep almost stable with increasing aging time from 300 h to 3000 h. In comparison, after aging at 700 °C, there are obvious changes in the high-temperature strength and the microstructures. The strengthening mechanisms of the 9Cr–3W–3Co steel were also discussed and the athermal yield stresses were calculated. The change of the high-temperature strength is mainly affected by the evolution of dislocations and laths. The precipitates mainly act as obstacles against motion of dislocations and lath boundaries

  12. Comparison of Chemical Sensitivity of Fresh and Long-Stored Heat Resistant Neosartorya fischeri Environmental Isolates Using BIOLOG Phenotype MicroArray System.

    Panek, Jacek; Frąc, Magdalena; Bilińska-Wielgus, Nina

    2016-01-01

    Spoilage of heat processed food and beverage by heat resistant fungi (HRF) is a major problem for food industry in many countries. Neosartorya fischeri is the leading source of spoilage in thermally processed products. Its resistance to heat processing and toxigenicity makes studies about Neosartorya fischeri metabolism and chemical sensitivity essential. In this study chemical sensitivity of two environmental Neosartorya fischeri isolates were compared. One was isolated from canned apples in 1923 (DSM3700), the other from thermal processed strawberry product in 2012 (KC179765), used as long-stored and fresh isolate, respectively. The study was conducted using Biolog Phenotype MicroArray platforms of chemical sensitivity panel and traditional hole-plate method. The study allowed for obtaining data about Neosartorya fischeri growth inhibitors. The fresh isolate appeared to be much more resistant to chemical agents than the long-stored isolate. Based on phenotype microarray assay nitrogen compounds, toxic cations and membrane function compounds were the most effective in growth inhibition of N. fischeri isolates. According to the study zaragozic acid A, thallium(I) acetate and sodium selenate were potent and promising N. fischeri oriented fungicides which was confirmed by both chemical sensitivity microplates panel and traditional hole-plate methods. PMID:26815302

  13. Heat resistant reduced activation 12% Cr steel of 16Cr12W2VTaB type-advanced structural material for fusion and fast breeder power reactors

    Ioltukhovskiy, A. G.; Leonteva-Smirnova, M. V.; Solonin, M. I.; Chernov, V. M.; Golovanov, V. N.; Shamardin, V. K.; Bulanova, T. M.; Povstyanko, A. V.; Fedoseev, A. E.

    2002-12-01

    Heat resistant 12% Cr steels of the 16Cr12W2VTaB type (12Cr-2W-V-Ta-B-0.16C) provide a reduced activation material that can be used as a structural material for fusion and fast breeder reactors. The composition under study meets scientific and engineering requirements and has an optimal base element composition to provide a δ-ferrite content of no more than 20%. It also has a minimum quantity of low melting impurity elements and non-metallic inclusions. Short-term tensile properties for the steel tested to 700 °C are provided after the standard heat treatment (normalization, temper). Rupture strength and creep properties for the steel depending on the initial heat treatment conditions are also given. The microstructural stability of the 16Cr12W2VTaB type steel at temperatures up to 650 °C is predicted to be good, and the properties of the steel after irradiation in BOR-60 are demonstrated.

  14. [Reactive oxygen forms and Ca ions as possible intermediaries under the induction of heat resistance of plant cells by jasmonic acid].

    Karpets, Iu V; Kolupaev, Iu E; Iastreb, T O; Obozny?, A I; Shvidenko, N V; Lugovaia, A A; Va?ner, A A

    2013-01-01

    The participation of reactive oxygen species (ROS) and calcium ions in realization of influence of exogenous jasmonic acid (JA) on the heat resistance of wheat coleoptiles has been investigated. Influence of 1 microM JA caused the transitional intensifying of generation of superoxide anion-radical (O2*-) and hydrogen peroxide in coleoptiles with the maximum within 15-30 minutes after the treatment beginning. Within the first hour after the beginning of coleoptiles treatment with JA the increase of superoxide dismutase (SOD) activity was noted. Later on (within 5-24 hours after the treatment beginning) there was the lowering of ROS generation by coleoptiles of experimental variant, and the SOD activity approached the control value. Intensifying of generation of superoxide radical induced by JA was suppressed by the antioxidant ionol and was partially levelled by imidazole (inhibitor of NADPH-oxidase), EGTA (chelator of extracellular calcium) and lanthanum chloride (calcium channels blocker). Pretreatment of coleoptiles with the ionol, imidazole, EGTA and LaC3l3 also partially removed the effect of increase of their resistance to the damaging heating caused by exogenous JA. It is supposed that the ROS generated with participation NADPH-oxidase, which activity depends on the receipt of calcium ions from extracellular space in the cytosol, are involved in realization of physiological effects of JA. PMID:23937049

  15. Effect of aging temperature on the microstructures and mechanical properties of ZG12Cr9Mo1Co1NiVNbNB ferritic heat-resistant steel

    Yang, Xue; Sun, Lan; Xiong, Ji; Zhou, Ping; Fan, Hong-yuan; Liu, Jian-yong

    2016-02-01

    The effect of aging on the mechanical properties and microstructures of a new ZG12Cr9Mo1Co1NiVNbNB ferritic heat resistant steel was investigated in this work to satisfy the high steam parameters of the ultra-supercritical power plant. The results show that the main precipitates during aging are Fe(Cr, Mo)23C6, V(Nb)C, and (Fe2Mo) Laves in the steel. The amounts of the precipitated phases increase during aging, and correspondingly, the morphologies of phases are similar to be round. Fe(Cr, Mo)23C6 appears along boundaries and grows with increasing temperature. In addition, it is revealed that the martensitic laths are coarsened and eventually happen to be polygonization. The hardness and strength decrease gradually, whereas the plasticity of the steel increases. What's more, the hardness of this steel after creep is similar to that of other 9%-12%Cr ferritic steels. Thus, ZG12Cr9Mo1Co1NiVNbNB can be used in the project.

  16. Creep strength and microstructural evolution of 9-12% Cr heat resistant steels during creep exposure at 600 C and 650 C

    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.)

  17. Heat-resistant and rigid-flexible coupling glass-fiber nonwoven supported polymer electrolyte for high-performance lithium ion batteries

    A heat-resistant and rigid-flexible coupling glass-microfiber nonwoven supported cyanoethyl-β-polyvinyl alcohol composite polymer electrolyte membrane (GFMPE) has been successfully fabricated explored for high-performance lithium batteries. It was demonstrated that the GFMPE possessed enhanced mechanical property, superior dimensional thermostability (>200 °C). In addition, Ethylene carbonate (EC)/Dimethyl carbonate (DMC) solvent soaked GFMPE exhibited a superior Li ion transport number of 0.86, wide electrochemical window up to 4.8 V vs Li+/Li and high ionic conductivity of 0.89 mS/cm at 25 °C. Moreover, LiCoO2/graphite cells using such polymer electrolyte with EC:DMC (1:1, v/v) showed excellent cycling stability and superior rate capability at room temperature. It is important to note that the LiFePO4/Li cell using GFMPE/propylene carbonate (PC) can also operate very well at an elevated temperature of 120 °C. These fascinating results would endow GFMPE a very promising polymer electrolyte in high-performance lithium batteries with improved safety and reliablity

  18. An irradiation test of heat-resistant ceramic composite materials. Interim report on post-irradiation examinations of the first preliminary irradiation test: 97M-13A

    Baba, Shin-ichi; Takahashi, Tsuneo; Ishihara, Masahiro; Hayashi, Kimio; Sozawa, Shizuo; Saito, Takashi [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Suzuki, Yoshio [Nuclear Engineering, Co. Ltd., Osaka (Japan); Saito, Tamotsu; Sekino, Hajime [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-03-01

    The Japan Atomic Energy Research Institute (JAERI) has been carrying out the research on radiation damage mechanism of heat-resistant ceramic composite materials, as one of the subjects of the innovative basic research on high temperature engineering using the High Temperature Engineering Test Reactor (HTTR). A series of preliminary irradiation tests is being made using the Japan Materials Testing Reactor (JMTR). The present report describes results of post-irradiation examinations (PIE) so far on specimens irradiated in the first capsule, designated 97M-13A, to fast neutron fluences of 1.2-1.8x10{sup 24} m{sup -2} (E>1 MeV) at temperatures of 573, 673 and 843 K. In the PIE, measurements were made on (1) dimensional changes, (2) thermal expansions, (3) X-ray parameters and (4) {gamma}-ray spectra. The results for the carbon/carbon and SiC/SiC composites were similar to those in existing literatures. The temperature monitor effect was observed both for SiC fiber- and particle-reinforced SiC composites as in the case of monolithic SiC. Namely, the curve of the coefficient of thermal expansion (CTE) of these specimens showed a rapid drop above a temperature around the irradiation temperature +100 K in the first ramp (ramp rate: 10 K/min), while in the second ramp the CTE curves were almost the same as those of un-irradiated SiC specimens. (author)

  19. Fire and heat resistant laminating resin based on maleimido and citraconimido substituted 1-(diorganooxyphosphonyl-methyl)-2,4- and -2,6-diaminobenzenes

    Beggs, James M. (inventor); Mikroyannidis, John A. (inventor); Kourtides, Demetrius A. (inventor)

    1988-01-01

    The subject invention pertains to a novel class of fire-and heat-resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituded 1-(dialkoxyphosphonyl)-methyl-2-4 and -2,6-diaminobenzenes. Typical polymer presursors have the chemical structure wherein R is alkyl, substituted alkyl or aryl, and R sup 1 is hydrogen or lower alkyl. The polymer precursors are prepared by reacting 1-(diorganooxyphosphonyl)methyl-2-4 and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chains extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-(diorganooxyphosphonyl)methyl-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic diandydride, or aryl diisocyanates, such as methylenebis (4-phenylisocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by differential scanning calorimetry (DSC) and the thermal stability of the polymers is ascertained by thermogravimetric analysis (TGA).

  20. XRD and TEM analysis of microstructure in the welding zone of 9Cr–1Mo–V–Nb heat-resisting steel

    Li Yajiang; Wang Juan; Zhou Bing; Feng Tao

    2002-06-01

    Under the condition of tungsten inert gas shielded welding (TIG) + shielded metal arc welding (SMAW) technology, the microstructure in the welding zone of 9Cr–1Mo–V–Nb (P91) heat-resisting steel is studied by means of X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The test results indicate that when the weld heat input () of TIG is 8.5 ∼ 11.7 kJ/cm and the weld heat input of SMAW is 13.3 ∼ 21.0 kJ/cm, the microstructure in the weld metal is composed of austenite and a little amount of ferrite. The substructure of austenite is crypto–crystal martensite, which included angle. There are some spot precipitates in the martensite base. TEM analysis indicates that the fine structure in the heat-affected zone is lath martensite. There are some carbides (lattice constant, 1.064 nm) at the boundary of grain as well as inside the grain, most of which are Cr23C6 and a little amount of (Fe, Me)23C6.

  1. Elevated levels of 70,000 dalton heat shock proteins in transiently thermotolerant Chinese hamster fibroblasts and in their stable heat resistant variants

    The function of one or more heat shock proteins (HSPs) may be to confer protection to cells against thermal damage. The quantitative relationship between heat sensitivity and concentration of several HSPs in thermotolerant Chinese hamster HA-1 cells and in their stable heat resistant variants (3011 and 2242) were examined. The presence or concentration of low molecular weight HSPs (22-27 kd) showed no correlation with cell survival after heat shock. In contrast, the concentration of 70 kd HSP correlated well with the logarithm of cell survival. To summarize, the data indicate that if any of the HSPs is indeed responsible for providing protection against heat-induced cell death, then the 70 kd HSP is the most likely candidate. It is not the rate of synthesis that is of importance, but the absolute level of this HSP. Furthermore, it does not matter whether the protein is induced in response to an earlier heat shock or is present in constitutive form. In either case the level of 70 kd HSP appears to be a good predictor of heat response

  2. Opportunities and challenges of spray forming high-alloyed steels

    Spray forming has proven to be a useful tool for generating high-alloyed materials. The metallurgical advantages of high solidification rates are obvious. Shortening of process chains in comparison to powder metallurgy is often discussed. To approach to some of the remaining questions, especially on the influence of process gases on spray forming steels, within this study high-alloyed steels with melt weights up to 150 kg are spray formed and hot worked to semi-finished materials. Properties are analyzed in comparison to products available on the market. Cold-work tool steels with high carbon content can be spray formed to produce materials with good wear resistance and toughness. When reducing the carbon content and the amount of hard carbides, advantage of reduced segregation becomes more apparent. On the other hand, the influence of nitrogen as an alloying element is more effective and means of control are required. When corrosion or heat resistant steels with high non-carbide bonded chromium content or other nitride forming elements are part of the alloy, care has to be taken on controlling the dissolution of process gases and subsequent precipitation and degassing during compaction and further processing. Experiments where melt protection and atomization gas were changed from nitrogen to argon have shown significant influence of process gases on spray forming results and the mechanical properties of the materials in hot worked and finally heat treated condition

  3. Creep property of carbon and nitrogen free high strength new alloys

    The carbon and nitrogen free new alloys which were composed of supersaturated martensitic microstructure with high dislocation density before the creep test have been investigated systematically. These alloys were produced from the new approach which raised creep strength by the utilization of the reverse transformed austenite phase as a matrix and intermetallic compounds such as Laves phase and mu-phase as precipitates during heating before the creep test. It is important that these alloys are independent of any carbides and nitrides as strengthening factors. The high temperature creep test over 700 oC exceeds 50,000 h, and the test is continuous. Creep behavior of the alloys is found to be different from that of the conventional high-Cr ferritic steels. The addition of boron to the alloy pulled the recrystallization temperature up in the high temperature, and it became a creep test in the un-recrystallization condition, and the creep property of high temperature over 700 oC was drastically improved. The minimum creep rates of Fe-Ni alloys at 700 oC are found to be much lower than those of the conventional high Cr ferritic heat resistant steels, which is due to fine dispersion strengthening useful even at 700 oC in these alloys. As a result it became clear that the value for 100,000 h was exceeded at 700 oC and 100 MPa calculated from the Larson-Miller parameter at C = 20.

  4. Technology readiness level (TRL) assessment of cladding alloys for advanced nuclear fuels

    Reliable fuel claddings are essential for the safe, sustainable and economic operation of nuclear stations. This paper presents a worldwide TRL assessment of advanced claddings for Gen III and IV reactors following an extensive literature review. Claddings include austenitic, ferritic/martensitic (F/M), reduced activation (RA) and oxide dispersion strengthened (ODS) steels as well as advanced iron-based alloys (Kanthal alloys). Also assessed are alloys of zirconium, nickel (including HastelloyR), titanium, chromium, vanadium and refractory metals (Nb, Mo, Ta and W). Comparison is made with Cf/C and SiCf/SiC composites, MAX phase ceramics, cermets and TRISO fuel particle coatings. The results show in general that the higher the maximum operating temperature of the cladding, the lower the TRL. Advanced claddings were found to have lower TRLs than the corresponding fuel materials, and therefore may be the limiting factor in the deployment of advanced fuels and even possibly the entire reactor in the case of Gen IV. (authors)

  5. Radiation and heat resistant mouldings

    Mouldings made of norbornene-ethylene-copolymers can be exposed to a radiation dose limit of 15 MGy, at an operating temperature of 373 K, without their stability values decreasing. Such mouldings can be used in medical engineering, e.g. medical instruments, container and apparatus parts; and in nuclear and radiation technology, e.g. casing parts, control devices and jacketings

  6. Heat resistance of Byssochlamys ascospores.

    Bayne, H G; Michener, H D

    1979-03-01

    Ascospores from 25 strains of Byssochlamys were studied for their ability to resist heat treatment in a standard defined medium. Seven of these were able to survive heating at 90 degrees C for 25 min or longer, when initial numbers were frequently near 10(6)/ml. Ascospores from five resistant strains suspended in the medium at pH 5.0 were usually more resistant than those at pH 3.6. Rapid heat inactivation occurred for one strain at pH 6.6. Nonlogarithmic heat death rate was observed in all strains tested. PMID:36842

  7. Inactivation of chemical and heat-resistant spores of Bacillus and Geobacillus by nitrogen cold atmospheric plasma evokes distinct changes in morphology and integrity of spores.

    van Bokhorst-van de Veen, Hermien; Xie, Houyu; Esveld, Erik; Abee, Tjakko; Mastwijk, Hennie; Nierop Groot, Masja

    2015-02-01

    Bacterial spores are resistant to severe conditions and form a challenge to eradicate from food or food packaging material. Cold atmospheric plasma (CAP) treatment is receiving more attention as potential sterilization method at relatively mild conditions but the exact mechanism of inactivation is still not fully understood. In this study, the biocidal effect by nitrogen CAP was determined for chemical (hypochlorite and hydrogen peroxide), physical (UV) and heat-resistant spores. The three different sporeformers used are Bacillus cereus a food-borne pathogen, and Bacillus atrophaeus and Geobacillus stearothermophilus that are used as biological indicators for validation of chemical sterilization and thermal processes, respectively. The different spores showed variation in their degree of inactivation by applied heat, hypochlorite, hydrogen peroxide, and UV treatments, whereas similar inactivation results were obtained with the different spores treated with nitrogen CAP. G. stearothermophilus spores displayed high resistance to heat, hypochlorite, hydrogen peroxide, while for UV treatment B. atrophaeus spores are most tolerant. Scanning electron microscopy analysis revealed distinct morphological changes for nitrogen CAP-treated B. cereus spores including etching effects and the appearance of rough spore surfaces, whereas morphology of spores treated with heat or disinfectants showed no such changes. Moreover, microscopy analysis revealed CAP-exposed B. cereus spores to turn phase grey conceivably because of water influx indicating damage of the spores, a phenomenon that was not observed for non-treated spores. In addition, data are supplied that exclude UV radiation as determinant of antimicrobial activity of nitrogen CAP. Overall, this study shows that nitrogen CAP treatment has a biocidal effect on selected Bacillus and Geobacillus spores associated with alterations in spore surface morphology and loss of spore integrity. PMID:25481059

  8. Thermophilic spore-forming bacteria isolated from spoiled canned food and their heat resistance. Results of a French ten-year survey.

    André, S; Zuber, F; Remize, F

    2013-07-15

    Thermal processing of Low Acid Canned Foods (LACF), which are safe and shelf-stable at ambient temperature for several years, results in heat inactivation of all vegetative microorganisms and the partial or total inactivation of spores. Good Manufacturing Hygienic Practices include stability tests for managing the pathogen risk related to surviving mesophilic bacterial spores. LACF are also often submitted to additional incubation conditions, typically 55 °C for 7 days, to monitor spoilage by thermophiles. In this study we identified the bacterial species responsible for non-stability after prolonged at 55 °C of incubation of LACF from 455 samples collected from 122 French canneries over 10 years. Bacteria were identified by microsequencing or a recent developed tool for group-specific PCR detection (SporeTraQ™). A single species was identified for 93% of examined samples. Three genera were responsible for more than 80% of all non-stability cases: mostly Moorella (36%) and Geobacillus (35%), and less frequently Thermoanaerobacterium (10%). The other most frequent bacterial genera identified were Bacillus, Thermoanaerobacter, Caldanaerobius, Anoxybacillus, Paenibacillus and Clostridium. Species frequency was dependent on food category, i.e. vegetables, ready-made meals containing meat, seafood or other recipes, products containing fatty duck, and related to the intensity of the thermal treatment applied in these food categories. The spore heat resistance parameters (D or δ and z values) from 36 strains isolated in this study were determined. Taken together, our results single out the species most suitable for use as indicators for thermal process settings. This extensively-documented survey of the species that cause non-stability at 55 °C in LACF will help canneries to improve the management of microbial contamination. PMID:23728430

  9. Optimization of in vitro regeneration and Agrobacterium tumefaciens-mediated transformation with heat-resistant cDNA in Brassica oleracea subsp. italica cv. Green Marvel.

    Ravanfar, Seyed Ali; Aziz, Maheran Abdul; Saud, Halimi Mohd; Abdullah, Janna Ong

    2015-11-01

    An efficient system for shoot regeneration and Agrobacterium tumefaciens-mediated transformation of Brassica oleracea cv. Green Marvel cultivar is described. This study focuses on developing shoot regeneration from hypocotyl explants of broccoli cv. Green Marvel using thidiazuron (TDZ), zeatin, and kinetin, the optimization of factors affecting Agrobacterium-mediated transformation of the hypocotyl explants with heat-resistant cDNA, followed by the confirmation of transgenicity of the regenerants. High shoot regeneration was observed in 0.05-0.1mgdm(-3) TDZ. TDZ at 0.1mgdm(-3) produced among the highest percentage of shoot regeneration (96.67%) and mean number of shoot formation (6.17). The highest percentage (13.33%) and mean number (0.17) of putative transformant production were on hypocotyl explants subjected to preculture on shoot regeneration medium (SRM) with 200M acetosyringone. On optimization of bacterial density and inoculation time, the highest percentage and mean number of putative transformant production were on hypocotyl explants inoculated with a bacterial dilution of 1:5 for 30min. Polymerase chain reaction (PCR) assay indicated a transformation efficiency of 8.33%. The luciferase assay showed stable integration of the Arabidopsis thaliana HSP101 (AtHSP101) cDNA in the transgenic broccoli regenerants. Three out of five transgenic lines confirmed through PCR showed positive hybridization bands of the AtHSP101 cDNA through Southern blot analysis. The presence of AtHSP101 transcripts in the three transgenic broccoli lines indicated by reverse transcription-PCR (RT-PCR) confirmed the expression of the gene. In conclusion, an improved regeneration system has been established from hypocotyl explants of broccoli followed by successful transformation with AtHSP101 for resistance to high temperature. PMID:25986972

  10. Modeling and experimental study of oil/water contact angle on biomimetic micro-parallel-patterned self-cleaning surfaces of selected alloys used in water industry

    Nickelsen, Simin; Moghadam, Afsaneh Dorri; Ferguson, J. B.; Rohatgi, Pradeep

    2015-10-01

    In the present study, the wetting behavior of surfaces of various common metallic materials used in the water industry including C84400 brass, commercially pure aluminum (99.0% pure), Nickle-Molybdenum alloy (Hastelloy C22), and 316 Stainless Steel prepared by mechanical abrasion and contact angles of several materials after mechanical abrasion were measured. A model to estimate roughness factor, Rf, and fraction of solid/oil interface, ƒso, for surfaces prepared by mechanical abrasion is proposed based on the assumption that abrasive particles acting on a metallic surface would result in scratches parallel to each other and each scratch would have a semi-round cross-section. The model geometrically describes the relation between sandpaper particle size and water/oil contact angle predicted by both the Wenzel and Cassie-Baxter contact type, which can then be used for comparison with experimental data to find which regime is active. Results show that brass and Hastelloy followed Cassie-Baxter behavior, aluminum followed Wenzel behavior and stainless steel exhibited a transition from Wenzel to Cassie-Baxter. Microstructural studies have also been done to rule out effects beyond the Wenzel and Cassie-Baxter theories such as size of structural details.

  11. Investigation of the structure of oxide scales on high temperature alloys using the glow discharge optical spectrometry

    The depth profiles of the chemical composition of the oxide scales on the high temperature alloys INCONEL alloy 617, HASTELLOY alloy X and INCOLOY alloy 800H were investigated by means of glow discharge optical spectrometry (GDOS). Due to the bombardment of the sample surface with energetic Ar ions, the scale was removed layer by layer. The sputtered species were excited to optical emission in the discharge plasma. Qualitative intensity-time curves were measured by time resolved registration of the intensity of characteristic emission lines for all elements of interest. The quantification of these curves, i.e. the conversion of the intensity into the elemental concentration and of the time into the depth, was the focus of this work. Mathematical correlations between the intensity of an emission line and the corresponding number of atoms in the plasma and the electrical discharge parameters are discussed in detail. An equation for the conversion of the emission line intensity into the elemental concentration was derived by direct measurement of the crater geometry as well as by the determination of the sputtering rate. It is shown that under identical discharge voltage and current the emission yield per atom does not depend on either the matrix from which it is sputtered or the bonding state of the atom. The results of the quantitative GDOS depth analyses were compared with those obtained by means of SIMS, SNMS, EPMA, metallography and x-ray phase analyses. Differences were discussed. (orig.)

  12. Silicon Alloying On Aluminium Based Alloy Surface

    Silicon alloying on surface of aluminium based alloy was carried out using electron beam. This is performed in order to enhance tribological properties of the alloy. Silicon is considered most important alloying element in aluminium alloy, particularly for tribological components. Prior to silicon alloying. aluminium substrate were painted with binder and silicon powder and dried in a furnace. Silicon alloying were carried out in a vacuum chamber. The Silicon alloyed materials were assessed using some techniques. The results show that silicon alloying formed a composite metal-non metal system in which silicon particles are dispersed in the alloyed layer. Silicon content in the alloyed layer is about 40% while in other place is only 10.5 %. The hardness of layer changes significantly. The wear properties of the alloying alloys increase. Silicon surface alloying also reduced the coefficient of friction for sliding against a hardened steel counter face, which could otherwise be higher because of the strong adhesion of aluminium to steel. The hardness of the silicon surface alloyed material dropped when it underwent a heating cycle similar to the ion coating process. Hence, silicon alloying is not a suitable choice for use as an intermediate layer for duplex treatment

  13. Fuel behavior in severe accidents and Mo-alloy based cladding designs to improve accident tolerance

    The severe accidents at TMI-2 and Fukushima-Daiichi led to core meltdown and hydrogen explosions. The main source of energy causing core melting is the decay heat from β-, β+, and γ decays of short-lived isotopes following a power scram. The exothermic reaction of Zr-alloy cladding can further increase the cladding temperature leading to rapid cladding corrosion and hydrogen production. The most effective mitigation to minimize core damage in a severe accident is to extend the duration of heat removal capacity via battery-supported passive cooling for as long as practically possible. Replacing the Zr-alloy cladding with a higher heat resistant cladding with lower enthalpy release rate may also provide additional coping time for accident management. Such a heat resistant cladding may also overcome the current licensing concerns about Zr-alloy hydriding and post quench ductility issues in a design base loss of coolant accident (LOCA). Zr-alloy cladding, while has been optimized for normal operation in high pressure water and steam of light water reactors, will rapidly lose its corrosion resistance and tensile and creep strength in high pressure steam. Evaluation of alternate cladding materials and designs have been performed to search for a new fuel cladding design which will substantially improve the safety margins at elevated temperatures during a severe accident, while maintaining the excellent fuel performance attributes of the current Zr-alloy cladding. The screening criteria for the evaluation include neutronic properties, material availability, adaptability and operability in current LWRs, resistance to melting. The new designs also need to be fabricable, maintain sufficient strength and resist to attack by high pressure steam. Engineering metals, alloys and ceramics which can meet some or most of these requirements are limited. Following review of the properties of potential candidates, it is concluded that molybdenum alloys may potentially achieve the largest improvement in fuel safety margins in a severe accident. To adopt molybdenum alloys for LWR fuel cladding application, a novel design of duplex and triplex Mo-Zr or Mo-advanced steel cladding is proposed as the best candidate for further development. The technical basis for selecting the Mo-Zr cladding out of several other potential candidates, and the approaches to overcome the weakness of the molybdenum alloys are discussed. (orig.)

  14. MATE (Materials for Advanced Turbine Engines) Program, Project 3. Volume 2: Design, fabrication and evaluation of an oxide dispersion strengthened sheet alloy combustor liner

    Bose, S.; Sheffler, K. D.

    1988-01-01

    The suitability of wrought oxide dispersion strengthened (ODS) superalloy sheet for gas turbine engine combustor applications was evaluated. Two yttria (Y2O3) dispersion strengthened alloys were evaluated; Incoloy MA956 and Haynes Development Alloy (HDA) 8077 (NiCrAl base). Preliminary tests showed both alloys to be potentially viable combustor materials, with neither alloy exhibiting a significant advantage over the other. MA956 was selected as the final alloy based on manufacturing reproducibility for evaluation as a burner liner. A hybrid PW2037 inner burner liner containing MA956 and Hastelloy X components and using a louvered configuration was designed and constructed. The louvered configuration was chosen because of field experience and compatibility with the bill of material PW2037 design. The simulated flight cycle for the ground based engine tests consisted of 4.5 min idle, 1.5 min takeoff and intermediate conditions in a PW2037 engine with average uncorrected combustor exit temperature of 1527 C. Post test evaluation consisting of visual observations and fluorescent penetrant inspections was conducted after 500 cycles of testing. No loss of integrity in the burner liner was shown.

  15. Isolamento e seleção de fungos filamentosos termorresistentes em etapas do processo produtivo de néctar de maçã Isolation and selection of heat resistant molds in the production process of apple nectar

    Beatriz de Cássia Martins Salomão

    2008-03-01

    Full Text Available Os fungos filamentosos termorresistentes são capazes de sobreviver aos processos de pasteurização aplicados aos produtos de frutas. Este estudo visou isolar e identificar fungos termorresistentes durante o processamento de néctar de maçã (pH 3,4 e 11,6 °Brix, de forma a selecionar o bolor mais termorresistente. O isolamento foi obtido após choque térmico de 70 °C/2 horas e incubação a 30 °C em PDA (3% de ágar acrescido de rosa de bengala. A identificação foi baseada na morfologia e nas estruturas micro e macroscópicas observadas após incubação das cepas em três diferentes meios (G25N, CYA e MEA e temperaturas. O fungo mais termorresistente foi selecionado pela aplicação de choques térmicos (de 80 °C/20 minutos até 97 °C/15 minutos. Foram detectadas 11 linhagens de bolores, sendo 5 termorresistentes. Dentre estas, três cepas, isoladas da matéria-prima e do concentrado de maçã, foram identificadas como Neosartorya fischeri; uma cepa isolada da matéria-prima foi identificada como Byssochlamys fulva, e uma cepa isolada do produto após a primeira pasteurização foi identificada como Eupenicillium sp. As cepas mais resistentes foram as de N. fischeri e B. fulva, que sobreviveram ao tratamento de 95 °C/20 minutos. Dentre as seis cepas restantes, uma foi identificada como Aspergillus sp., entretanto, nenhuma destas apresentou termorresistência.Heat resistant molds are able to survive the pasteurization process applied to apple products. This study aimed at detecting and identifying heat resistant molds during the processing of apple nectar (pH 3.4; 11.6 °Brix in order to select the most heat resistant mold. The isolation was carried out after heat shock at 70 °C, during 2 hours, and incubation at 30 °C, in PDA (3% agar, where rose bengal was added. The identification of macro and microscopic structures was carried out after incubation in three different media (G25N, CYA, MEA and temperatures. Different heat shocks, from 80 °C/20 minutes to 97 °C/15 minutes, were applied to select the most heat resistant mold. Eleven strains were selected, of which five were heat-resistant: three strains were isolated from apple and concentrated apple juice and were identified as Neosartorya fischeri; one strain, isolated from apple, was identified as Byssochlamys fulva and one strain, isolated from the product after the first pasteurization, was identified as Eupenicillium sp. The most heat-resistant strains belong to N. fischeri and B. fulva, which were able to survive at 95 °C/20 minutes. Among the six remaining, one was identified as Aspergillus sp., however, none of them was heat resistant.

  16. On the problem of creation of structural materials on the basis of hard alloys

    Chemical composition and structure of refractory skeletons produced by the methods of self-propagating high temperature synthesis (SHS) and powder metallurgy were studied for their effects on high temperature mechanical properties hard alloys on these skeletons base. Porous skeletons were obtained on the base of TiC0.55; TiC0.65; TiC0.75; TiC0.85 and TiC1.0 carbides with their subsequent impregnation with heat resisting nickel base alloy ZhS6U. It was shown that a sintered skeleton was prone to fracture while SHS-skeleton preserved its structure. Optimal operating temperature of materials considered was noted to depend on the temperatures of brittle-ductile transition and transition into superplastic stable of refractory phase

  17. The effect of aging treatment on the high temperature fatigue strength and fatigue fracture behaviour of friction welded domestic heat resisting steels (SUH3-SUS303)

    In this study the experiment was carried out as the high temperature rotary bending fatigue testing under the condition of 7000C high temperature to the friction welded domestic heat resisting steels, SUH3-SUS303, which were 10 hr., 100 hr. aging heat treated at 7000C after solution treatment 1 hr. at 10600C for the purpose of observing the effects of the high temperature fatigue strength and fatigue fracture behaviours as well as with various mechanical properties of welded joints. The results obtained are summarized as follows: 1) Through mechanical tests and microstructural examinations, the determined optimum welding conditions, rotating speed 2420 rpm, heating pressure 8 kg/mm2, upsetting pressure 22 kg/mm2, the amount of total upset 7 mm (heating time 3 sec and upsetting time 2 sec) were satisfied. 2) The solution treated material SUH3, SUS303 and SUH3-SUS303, have the highest inclination gradiant on S-N curve due to the high temperature fatigue testing for long time at 7000C. 3) The optimum aging time of friction welded SUH3-SUS303, has been recognized near the 10 hr. at 7000C after the solution treatment of 1 hr. at 10600C. 4) The high temperature fatigue limits of aging treated materials were compared with those of raw material according to the extender of aging time, on 10 hr. aging, fatigue limits were increased by SUH3 75.4%, SUS303 28.5%, friction welded joints SUH3-SUS303 44.2% and 100 hr. aging the rate were 64.9%, 30.4% and 36.6% respectively. 5) The fatigue fractures occurred at the side of the base metal SUS303 of the friction welded joints SUH3-SUS303 and it is difficult to find out fractures at the friction welding interfaces. 6) The cracking mode of SUS303, SUH3-SUS303 is intergranular in any case, but SUH3 is fractured by transgranular cracking. (author)

  18. Heat-Resistant Ferritic-Martensitic Steel RUSFER-EK-181 (Fe-12Cr-2W-V-Ta-B) for Fusion Power Reactor

    Full text: The study of initial (unirradiated) functional properties of Russian RAFMS RUSFER-EK-181 (Fe-12Cr-2W-V-Ta-B) as advanced heat-and radiation-resistant structural material for fusion power reactors has been continued. RUSFER-EK-181 steel is related to precipitation hardening (nanostructured) materials type. The regularities of low temperature brittle fracture (crack growth resistance) of the steel at static and dynamic concentrated loads depending on the sizes of Charpy V-Noch (CVN) specimens, type of stress concentrators (V-notches or a fatigue crack) were investigated in the temperature range from -196 deg. C to +100 deg. C. Fracture toughness tests estimating KIC and JIC (static concentrated bending) were conducted. The ductile-to-brittle transition temperatures (DBTT) were determined in the range from -85 deg. C to +35 deg. C depending on the type of CVN-specimens and stress states (fatigue crack, central and side V-notches). The work of low temperature fracture of the steel depends on the type of the stress concentrators and specimen sizes and is governed by the elastic energy store and the conditions of plastic deformation in the near-surface layers of the specimens regulated by side notches. The marked level of permanent deformation and impact toughness (not less than 3 - 5 J/cm2) was observed at low temperatures (lower than DBTT). Short-term (yield strength, ultimate strength, elongation to rupture) and long-term (creep, diagram 'stress vs time to rupture') properties, temperature conductivity, thermal conductivity and linear expansion of the steel were investigated in the temperature range to 750oC. Diffusion characteristics of self-point defects (vacancies and interstitial atoms) in iron crystal with dislocations of different types were calculated by the methods of multiscale modeling in the temperature range from room temperature to 1000K. Nuclear transmutation changes of the chemical composition and the structure and phase state (Schaeffler diagram) of the steel were calculated for the long-term irradiation in neutron spectrum of the fusion reactor DEMO-RF. Obtained data for functional properties of the RAFMS RUSFER-EK-181 characterize it as the nanostructured structural steel with a good heat resistant (up to 700oC), good resistance to low temperature embrittlement, sufficient radiation resistance of the chemical composition and the structure and phase state. (author)

  19. The Change of the Mechanical Properties and of the Structure of the Alloy during Gradual Approach of its Composition from Fe-40Al to Fe-43Al-4C (at. %)

    Kratochvíl, P.; Dobeš, Ferdinand; Milička, Karel; Pešička, J.

    Duebendorf : EMPA - Materials Science and Technology, 2007 - (Palm, M.; Spiegel, M.; Stein, F.; Krein, R.). s. 42-42 [Discussion Meeting on the Development of Innovative Iron Aluminium Alloys /4./. 21.10.2007-24.10.2007, Interlaken] R&D Projects: GA ČR GA106/05/0409; GA ČR GA106/06/0019 Institutional research plan: CEZ:AV0Z20410507 Keywords : creep * iron aluminide (FeAl type) * heat-resistant alloy Subject RIV: JG - Metallurgy

  20. Influence of content of lanthanum, cerium and rhenium in filler material on properties of heat-resisting metal built-up by argon arc process

    Mechanical behaviour and resistance to hot cracking have been studied of a refractory metal welded joints deposited by argon arc welding. The nickel-chrome based metal was alloyed by lanthanum, cerium and rhenium. At La and Ce concentrations above 0.1% the strength and plasticity of the welded metal sharply decrease at 20 deg and 800 deg C due to grain boundary embrittlement on account of a second phase formation. As the Re content grows to 6%, the strength and plasticity increase as the solid solution is strengthened. It is recommended to limit La and Ce content in the additives by 0.1% or to additionally alloy them by 1.5. Re

  1. Substitution of Nickel by Combined Addition of Cobalt and Zirconium in Alloy A 332

    Wüstenhagen, Andreas; Tonn, Babette

    2011-01-01

    Due to the increasing international competition and the resulting pricing pressure it is imperative to avoid the use of expensive alloying elements during the production of aluminium castings. The piston alloy A 332 shows an optimum combination of mechanical and casting properties and an attractive cost-performance ratio whereas nickel is the most expensive alloying element. A substitution of nickel by a combined addition of low contents of cobalt and zirconium has the potential capacitiy to increase the mechanical properties and reduce the costs of the alloy. At Clausthal University of Technology Thermo-Calc simulations and casting experiments were carried out to investigate the effect of the nickel subtitution. Thermo-Calc-simulations were made to analyze the intermetallic phases in these alloys. These simulations were evaluated by observations under optical microscope and SEM of specimens poured into permanent moulds. The size and morphology of the intermetallic phases and the primary silicon was analyzed by the use of image analysis software. The mechanical properties of the alloys were determined by tensile tests at room temperature, 250° C and 350° C. The tensile specimens were tested in as-cast and pre-aged condition. The effect on the castability was characterized by determining the flow length and the susceptibility to form shrinkages and hot cracks. The standard alloy A 332 and the new piston alloy with cobalt and zirconium were compared. The new alloy AlSi12,6Cu1Mg1CoZr exhibits a yield strength of 115 MPa and a tensile strength of 171 MPa at 250° C in pre-aged condition (250° C/100 h). At 350° C the new alloy displays a yield strength of 57 MPa and a tensile strength of 85 MPa in pre-aged condition (350° C/100h). Compared to the reference alloy AlSi12,6Cu1Ni1Mg1 the yield strength at 250° C was improved about 25% and the yield strength at 350° C about 7%. The favorable castability of the reference alloy is not affected by the substitution of nickel. These results prove the development of a heat-resistant, thermally stable alloy without nickel. The mechanical properties and the cost-performance ratio are superior to the standard alloy. The competitiveness of the new piston alloy was improved significantly.

  2. Stacking faults and transformation of γ' metastable precipitates in an Fe-29Ni-22Co-4Nb-2Cr-1Ti-0.5Al-0.5Si alloy

    In this study, we investigate an Fe-29Ni-22Co-4Nb-2Cr-1Ti-0.5Al-0.5Si heat resistant alloy (refer to herein as alloy 929C), in which the γ' phase is the precipitation-strengthening phase. The specimens of alloy 929C are solid-solution heat treated and aged within a temperature range of 993 to 1073K for up to 1440ks. The morphological and structural changes of the precipitates in the alloy are analyzed by transmission electron microscopic observation. Internal-fringe contrast, which suggests the existence of stacking faults on the {111}γ, plane, is found in many of the large γ' precipitates formed in the speciments at the latter stage of aging at temperatures above 1033 K. The metastable γ' precipitates, of which some have stacking faults, are gradually transformed into a stable η phase during aging. The effects of stacking faults introduced by cold-rolling into the γ' particles on the formation of η phase are studied by subsequent annealing heat treatments. The selected-area electron diffraction (SAED) patterns of the cold-rolled and annealed particles show that the metastable γ' precipitates with stacking faults are transformed intensively into a stable η phase. In this paper, we discuss in detail the basis of these morphological and structural changes of the precipitates in heat-resistant alloys. (author)

  3. Effect of Pr addition on microstructure and mechanical properties of AZ61 magnesium alloy

    You Zhiyong

    2014-03-01

    Full Text Available To improve the strength, hardness and heat resistance of Mg-6Al-1Zn (AZ61 alloy, the effects of Pr addition on the as-cast microstructure and mechanical properties of AZ61 alloy were investigated at room and elevated temperatures by means of Brinell hardness measurement, optical microscope (OM, scanning electron microscope (SEM, energy dispersive spectroscopy (EDS, X-ray diffractometer (XRD and DNS100 electronic universal testing machine. The results show that the microstructures of Pr-containing AZ61 alloys were refined, with primary ?-Mg17Al12 phase distributed homogeneously. When the addition of Pr is up to 1.2wt.%, the ? phase becomes finer, and new needle-like or short-rod shaped Al11Pr3 phase and blocky AlPr phase appear. As a result, optimal tensile properties are obtained. However, greater than 1.2wt.% Pr addition leads to poorer mechanical properties due to the aggregation of the needle-like phase and large size of grains. The present research findings provide a new way for strengthening of magnesium alloys at room and elevated temperatures, and a method of producing thermally-stable AZ61 magnesium alloy.

  4. Study of cutting speed on surface roughness and chip formation when machining nickel-based alloy

    Nickel- based alloy is difficult-to-machine because of its low thermal diffusive property and high strength at higher temperature. The machinability of nickel- based Hastelloy C-276 in turning operations has been carried out using different types of inserts under dry conditions on a computer numerical control (CNC) turning machine at different stages of cutting speed. The effects of cutting speed on surface roughness have been investigated. This study explores the types of wear caused by the effect of cutting speed on coated and uncoated carbide inserts. In addition, the effect of burr formation is investigated. The chip burr is found to have different shapes at lower speeds. Triangles and squares have been noticed for both coated and uncoated tips as well. The conclusion from this study is that the transition from thick continuous chip to wider discontinuous chip is caused by different types of inserts. The chip burr has a significant effect on tool damage starting in the line of depth-of-cut. For the coated insert tips, the burr disappears when the speed increases to above 150 m/min with the improvement of surface roughness; increasing the speed above the same limit for uncoated insert tips increases the chip burr size. The results of this study showed that the surface finish of nickel-based alloy is highly affected by the insert type with respect to cutting speed changes and its effect on chip burr formation and tool failure

  5. Corrosion screening tests with Ni-base alloys in supercritical water containing hydrochloric acid and oxygen

    Corrosion of reactor material during oxidation of hazardous organic waste containing chloride proceeds very fast and constitutes one major problem in SCWO applications. The following Ni-base alloys were tested within the framework of the experimental program: Inconel 625 and 686, Hastelloy C-276, Nicrofer 5923 and 6025, and Haynes alloy 214. Test tubes were fabricated from these materials and exposed to SCWO conditions, without organics, at temperatures up to 600 C and pressures up to 34 MPa. Higher concentrated HCl solutions or the combination of oxygen and HCl cause strong surface destruction. The corrosion measured was higher at lower temperatures and at higher pressures, if all other conditions remained constant. The most severe corrosion--general corrosion with SCC and pitting--appeared at temperatures near the critical temperature, i.e., in the preheater and cooling sections of the test tubes. The corrosion products were insoluble in supercritical water and formed thick layers in the supercritical part of the reactor. Under these layers only minor corrosion occurred

  6. Characterization of complex carbide–silicide precipitates in a Ni–Cr–Mo–Fe–Si alloy modified by welding

    Nickel based alloys of the type Hastelloy-N™ are ideal candidate materials for molten salt reactors, as well as for applications such as pressure vessels, due to their excellent resistance to creep, oxidation and corrosion. In this work, the authors have attempted to understand the effects of welding on the morphology, chemistry and crystal structure of the precipitates in the heat affected zone (HAZ) and the weld zone of a Ni–Cr–Mo–Fe–Si alloy similar to Hastelloy-N™ in composition, by using characterization techniques such as scanning and transmission electron microscopy. Two plates of a Ni–Cr–Mo–Fe–Si alloy GH-3535 were welded together using a TiG welding process without filler material to achieve a joint with a curved molten zone with dendritic structure. It is evident that the primary precipitates have melted in the HAZ and re-solidified in a eutectic-like morphology, with a chemistry and crystal structure only slightly different from the pre-existing precipitates, while the surrounding matrix grains remained unmelted, except for the zones immediately adjacent to the precipitates. In the molten zone, the primary precipitates were fully melted and dissolved in the matrix, and there was enrichment of Mo and Si in the dendrite boundaries after solidification, and re-precipitation of the complex carbides/silicides at some grain boundaries and triple points. The nature of the precipitates in the molten zone varied according to the local chemical composition. - Graphical abstract: Display Omitted - Highlights: • Ni-based alloy with Cr, Mo, Si, Fe and C was welded, examined with SEM, EBSD, and TEM. • Original Ni2(Mo,Cr)4(Si,C) carbides changed from equiaxed to lamellar shape in HAZ. • Composition and crystal structure remained almost unchanged in HAZ. • Original carbides changed to lamellar Ni3(Mo,Cr)3(Si,C) in some cases in weld metal. • Precipitates were mostly incoherent, but semi-coherent in some cases in weld metal

  7. Mechanical properties of pure Ni and Ni-alloy substrate materials for Y Ba Cu O coated superconductors

    Clickner, C. C.; Ekin, J. W.; Cheggour, N.; Thieme, C. L. H.; Qiao, Y.; Xie, Y.-Y.; Goyal, A.

    2006-06-01

    Mechanical properties of rolling-assisted, biaxially-textured substrates (RABiTS) and substrates for ion-beam assisted deposition (IBAD) coated superconductors are measured at room temperature, 76, and 4 K. Yield strength, Young's modulus, and the proportional limit of elasticity are determined, tabulated and compared. Results obtained are intended to serve as a database of mechanical properties of substrates having the same anneal state and texture as those incorporated in the general class of RE-Ba-Cu-O coated conductor composites (RE = rare earth). The RABiTS materials measured are pure Ni, Ni-13at.%Cr, Ni-3at.%W-2at.%Fe, Ni-10at.%Cr-2at.%W, and Ni-5at.%W. The IBAD substrate materials included Inconel 625 and Hastelloy C-276. The Ni alloys are substantially stronger and show higher strains at the proportional limit than those of pure Ni. Substrates fully coated with buffer layers, ?1 ?m of Y-Ba-Cu-O, and 3-5 ?m of Ag have similar mechanical properties (at 76 K) as the substrate alone. Somewhat surprisingly, plating an additional 30-40 ?m of Cu stabilizer onto high-yield-strength (690 MPa) Hastelloy coated conductors 100 ?m thick, reduces the overall yield strength of the composite structure by only about 10-12% at 76 K and 12-14% at room temperature; this indicates that the Cu layer, despite its relatively soft nature, contributes significantly to the overall strength of even high-strength coated conductors.

  8. Corrosion resistance of Ni-Cr-Mo alloys. Chemical composition and metallurgical condition's effects

    Ni-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly-corrosive environments. This versatility is due to the excellent performance of nickel in hot alkaline solutions and the beneficial effect of chromium and molybdenum in oxidizing and reducing conditions, respectively. Alloy C-22 (22 % Cr-13 % Mo-3% W) is a well known versatile member of this family. Due to its excellent corrosion resistance in a wide variety of environments, Alloy C-22 has been selected for the fabrication of the corrosion-resistant outer shell of the high-level nuclear waste container. The increasing demand of the industry for corrosion resistant alloys with particular properties of corrosion and mechanical resistance has led to the development of new alloys. Alloy C-22HS (Ni-21 % Cr-17 % Mo) is a new high-strength corrosion resistant material recently developed and introduced into the market. This alloy provides a corrosion resistance comparable with that of other C-type alloys, and it can also be age hardened to effectively double its yield strength. HASTELLOY HYBRID-BC1 (Ni-22 % Mo-15 % Cr) is a new development intended for filling the gap between Ni-Mo and Ni-Cr-Mo alloys. This novel alloy is able to withstand HCl and H2SO4, even in the presence of dissolved oxygen and other oxidizing species. Its resistance to chloride-induced pitting corrosion, crevice corrosion and stress corrosion cracking is also remarkable. Thermal aging of Ni-Cr-Mo alloys leads to microstructure changes depending on the temperature range and exposure time at temperature. A Long Range Ordering (LRO) reaction can occur in the range of 350 C degrees to 600 C degrees, producing an ordered Ni2(Cr,Mo) phase. This ordering reaction does not seem to affect the corrosion resistance and produces only a slight loss in ductility. LRO transformation is homogeneous and has proven to be useful to fabricate the age-hard enable Alloy C22-HS. Tetrahedral Close Packed (TCP) phases, like μ, σ and P, may form if Ni-Cr-Mo alloys are exposed for tens of hours in the range of 600 C degrees to 1100 C degrees. These phases could have a detrimental effect upon corrosion resistance and cause a loss of mechanical ductility. The precipitation of TCP phases starts at grain boundaries and for long aging times it progresses to twins boundaries and then the grain bodies. TCP phases are rich in Mo and Cr. Zones in the matrix adjacent to the TCP precipitates may be depleted of Cr and Mo, and the alloy becomes sensitized.The aim of the present work was to compare the general corrosion rate and the crevice corrosion susceptibility of alloys C-22, C-22HS and HYBRID-BC1 in different metallurgical conditions when exposed to hot chloride solutions. The effects of the alloy composition and different heat treatments were assessed. (author)

  9. Influence of preliminary heat treatment of heat resistant steels of pearlite class on the tendency of welded joints to fractures in reheating

    The effect of the initial state of steels 12Kh1MF and 15Kh3m1F on their trend toward failure on second heating is studied. Annealed steel specimens have been subjected to various kinds of heat treatment. The dependence is established of the kinetics of dissolution of carbides in nonequilibrium welding heating on the properties of the alloys and the welding regime. As the activation energy of diffusion of the elements forming the carbide increases, the rate of solution sharply reduces, and the temperature of complete dissolution of the carbide increases. A reduction in the initial size of the carbide particles decreases the time of their dissolution and increases the probability of their complete dissolution under given welding conditions

  10. Hydrofluoric Acid Corrosion Study of High-Alloy Materials

    A corrosion study involving high-alloy materials and concentrated hydrofluoric acid (HF) was conducted in support of the Molten Salt Reactor Experiment Conversion Project (CP). The purpose of the test was to obtain a greater understanding of the corrosion rates of materials of construction currently used in the CP vs those of proposed replacement parts. Results of the study will help formulate a change-out schedule for CP parts. The CP will convert slightly less than 40 kg of 233U from a gas (UF6) sorbed on sodium fluoride pellets to a more stable oxide (U3O8). One by-product of the conversion is the formation of concentrated HF. Six moles of highly corrosive HF are produced for each mole of UF6 converted. This acid is particularly corrosive to most metals, elastomers, and silica-containing materials. A common impurity found in 233U is 232U. This impurity isotope has several daughters that make the handling of the 233U difficult. Traps of 233U may have radiation fields of up to 400 R at contact, a situation that makes the process of changing valves or working on the CP more challenging. It is also for this reason that a comprehensive part change-out schedule must be established. Laboratory experiments involving the repeated transfer of HF through 1/2-in. metal tubing and valves have proven difficult due to the corrosivity of the HF upon contact with all wetted parts. Each batch of HF is approximately 1.5 L of 33 wt% HF and is transferred most often as a vapor under vacuum and at temperatures of up to 250 C. Materials used in the HF side of the CP include Hastelloy C-276 and Monel 400 tubing, Haynes 230 and alloy C-276 vessels, and alloy 400 valve bodies with Inconel (alloy 600) bellows. The chemical compositions of the metals discussed in this report are displayed in Table 1. Of particular concern are the almost 30 vendor-supplied UG valves that have the potential for exposure to HF. These valves have been proven to have a finite life due to failure, most often at the bellows flange ring. It was discovered that the entire bellows assembly was not all alloy 600 but that alloy 600 bellows had been welded to a stainless steel alloy 316 (SS-316) flange ring. A previous study documents and addresses this problem.1 The fabricators of the valves immediately corrected the problem and began fabricating all wetted parts of the bellows assembly from alloy 600. At the same time, the fabricators began to make alloy C-276 valve bodies and stem tips available for sale. This material is known to be superior to the alloy 400 valve bodies and stem tips of the standard UG valves that had already been installed in the CP. A decision was made to purchase alloy C-276 bodies and stem tips and to change out those alloy 400 components that had already been installed. Due to the enormity of this task (both in terms of time and money), it was desirable to determine the longevity of alloy C-276 vs alloy 400 components in a side-by-side comparison. Also of interest was the question of how long the new (all-alloy 600) bellows would last in comparison with the original alloy 600/SS-316 bellows. A basic HF corrosion test was proposed to compare corrosion rates of several high-alloy materials. Because much of the alloy 400 in the system had been gold plated, some gold-plated alloy 400 coupons were included. Due to time and funding limitations, actual CP variables such as temperature and pressure were not duplicated. Instead, a simple partial-immersion test at ambient temperature was conducted. The purpose of this test was to gain information on the rate of corrosion of different alloys in the CP and to attempt to derive some idea of their expected lifetimes in the operating environment

  11. Promising technologies for the surface treatment at production and repair of Ti alloys vanes of gas turbine engines with the help of power ion and electron beams

    By means of AES, SEM, TEM, X-ray diffraction, exoelectron emission as well as by optical metallography in polarized light physical and chemical properties of the surface layers of heat-resistant Ti-based alloys (VT6, VT8, VT9) for application in aviation gas turbine engines exposed to power pulsed ion and electron beams have been investigated. A comparative fatigue tests as well as corrosion and erosion ones of initial serial and irradiated turbine blades were carried out. Perspective fields for the pulsed ion and electron beams application are chosen

  12. Gas-metal reactions of a new Fe-Ni-Cr-W alloy in helium with reactive components and in an H2-CH4-H2S atmosphere in the temperature range 700-9500C

    A new heat resistant e-Ni-Cr-W alloy (Thermon 4972) was developed within the scope of the prototype nuclear process plant project. This alloy shows mechanical properties and creep rupture properties similar to those of the nickel-based alloy Inconel 617 but, in addition, the new alloy forms protective oxide layers in atmospheres with very low O2 partial pressures. It is shown, by means of some examples, that a variation in the oxide morphology is caused by the modification of the alloy. However, the modifications lead to changes in the carbon activity of the alloy in comparison with the carbon activity of the atmosphere. Both activities must be adjusted to avoid processes such as carburization or decarburization. The results of experiments carried out for durations up to 2000 h at temperatures between 750 and 9500C are compared with those of the alloy Inconel 617. Experiments in sulphidizing and carburizing gas atmospheres were carried out to examine the protective behaviour of the layers built up in H2-CH4-H2S atmospheres with H2O contents between 10% and 10-3%. It is shown that, with an increase in the O2 partial pressure, the layers change from sulphide to oxide. At the same time there is a large variation in the specific mass change. The results are important for the application of the new alloy in plants for coal conversion and are compared with those obtained with the alloy Inconel 800 H. (orig.)

  13. Effect of coating and surface modification on the corrosion resistance of selected alloys in supercritical water

    Materials selection is one of the key tasks in Gen-IV reactor development. There is no known material that can meet the expected core outlet conditions of the Canadian SCWR concept (625oC core outlet temperature). High-Cr steels with excellent corrosion resistance are often susceptible to embrittlement due to the precipitation of sigma and other phases in the microstructure. Low-Cr steels such as P91 and oxide dispersion strengthened (ODS) steels exhibit good high-temperature mechanical properties, but the lack of sufficient Cr content makes this group alloy corrode too fast. Improvement in this alloy is needed in order for it to be considered as a piping construction material. In this report, the development of a metallic coating on a P91 substrate is discussed. Recent effort on selection of in-core cladding alloys has focused on heat-resistant 3xx series stainless steels. These alloys have higher strength at high-temperature ranges, but corrosion and stress-corrosion cracking resistance are a concern. Metallic coating and surface modification are considered as possible solutions to overcome this challenge. The effects of surface modification on the corrosion rate of austenitic steels were also reported in this paper. As-machined surface showed much better corrosion resistance than polished surface and advanced surface analyses showed distinct differences in the nature and the morphology of the surface layer metal. Possible mechanisms for improved corrosion performance are discussed. (author)

  14. Translating VDM to Alloy

    Lausdahl, Kenneth

    2013-01-01

    . Traditionally, theorem provers are used to prove that specifications are correct but this process is highly dependent on expert users. Alternatively, model finding has proved to be useful for validation of specifications. The Alloy Analyzer is an automated model finder for checking and visualising Alloy...... specifications. However, to take advantage of the automated analysis of Alloy, the model-oriented VDM specifications must be translated into a constraint-based Alloy specifications. We describe how a sub- set of VDM can be translated into Alloy and how assertions can be expressed in VDM and checked by the Alloy...

  15. Tantalum-niobium alloys

    Presented is the review of physical, chemical, mechanical and technological properties of tantalum-niobium alloys which form a contineous series of solid solutions. The above alloys used in the production of various devices operating in reactive media. Results of investigations of Ta-Nb alloys of various compositions using mono and polycrystal samples at the temperatures from -195 to 1800 deg C are summarized. Prospects for tantalum substitution for Ta-Nb alloys due to reduction of the consumption of expensive tantalum and usability of unseparated mixture of tantalum-niobium oxides as raw mateirals for alloy fabrication are noted. Methods of fabrication and working of Ta-Nb alloys are described

  16. Assessment of Embrittlement of VHTR Structural Alloys in Impure Helium Environments

    Crone, Wendy; Cao, Guoping; Sridhara, Kumar

    2013-05-31

    The helium coolant in high-temperature reactors inevitably contains low levels of impurities during steady-state operation, primarily consisting of small amounts of H{sub 2}, H{sub 2}O, CH{sub 4}, CO, CO{sub 2}, and N{sub 2} from a variety of sources in the reactor circuit. These impurities are problematic because they can cause significant long-term corrosion in the structural alloys used in the heat exchangers at elevated temperatures. Currently, the primary candidate materials for intermediate heat exchangers are Alloy 617, Haynes 230, Alloy 800H, and Hastelloy X. This project will evaluate the role of impurities in helium coolant on the stress-assisted grain boundary oxidation and creep crack growth in candidate alloys at elevated temperatures. The project team will: • Evaluate stress-assisted grain boundary oxidation and creep crack initiation and crack growth in the temperature range of 500-850°C in a prototypical helium environment. • Evaluate the effects of oxygen partial pressure on stress-assisted grain boundary oxidation and creep crack growth in impure helium at 500°C, 700°C, and 850°C respectively. • Characterize the microstructure of candidate alloys after long-term exposure to an impure helium environment in order to understand the correlation between stress-assisted grain boundary oxidation, creep crack growth, material composition, and impurities in the helium coolant. • Evaluate grain boundary engineering as a method to mitigate stress-assisted grain boundary oxidation and creep crack growth of candidate alloys in impure helium. The maximum primary helium coolant temperature in the high-temperature reactor is expected to be 850-1,000°C.Corrosion may involve oxidation, carburization, or decarburization mechanisms depending on the temperature, oxygen partial pressure, carbon activity, and alloy composition. These corrosion reactions can substantially affect long-term mechanical properties such as crack- growth rate and fracture toughness, creep rupture, and fatigue. Although there are some studies on the effects of impurities in helium coolant on creep rupture and fatigue strength, very little is known about their effects on creep crack initiation and crack growth rate at elevated temperatures.

  17. Ferroelectric and ferromagnetic properties of epitaxial BiFeO3-BiMnO3 films on ion-beam-assisted deposited TiN buffered flexible Hastelloy

    Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO3)0.5:(BiMnO3)0.5 [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La0.7Sr0.3MnO3 (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9??C/cm2. The magnetization of the BFO-BMO/LSMO is 62?emu/cc at room temperature

  18. Alloy Fabrication Laboratory

    Federal Laboratory Consortium — At NETL’s Alloy Fabrication Facility in Albany, OR, researchers conduct DOE research projects to produce new alloys suited to a variety of applications, from gas...

  19. Turbine Blade Alloy

    MacKay, Rebecca

    2001-01-01

    The High Speed Research Airfoil Alloy Program developed a fourth-generation alloy with up to an +85 F increase in creep rupture capability over current production airfoil alloys. Since improved strength is typically obtained when the limits of microstructural stability are exceeded slightly, it is not surprising that this alloy has a tendency to exhibit microstructural instabilities after high temperature exposures. This presentation will discuss recent results obtained on coated fourth-generation alloys for subsonic turbine blade applications under the NASA Ultra-Efficient Engine Technology (UEET) Program. Progress made in reducing microstructural instabilities in these alloys will be presented. In addition, plans will be presented for advanced alloy development and for computational modeling, which will aid future alloy development efforts.

  20. Fundamental considerations for the development of oxidation-resistant alloys and coatings based on ?-TiAl

    Singheiser, L.; Niewolak, L.; Shemet, V.; Quadakkers, W. J.; Flesch, U.

    2003-10-01

    Alloys based on ?-TiAl are promising high-temperature materials that may replace conventional heat-resistant steels and superalloys in applications where high strength in combination with low density is required. However, an important hindrance to the use of ?-TiAl alloys at high temperatures is their relatively poor oxidation resistance and sensitivity against environmentally induced embrittlement. This material degradation is related to the poor protective properties of the mixed TiO2/Al2O3 surface scales which form on the surface during high-temperature exposure. Recently, it was shown that protective alumina scale formation on ?-TiAl can be obtained by small additions of Ag. This effect was found to be related to the formation of Z phase in the subscale depletion layer at the expense of ? 2-Ti3Al. It was found that the beneficial effect of Ag can be suppressed if the alloys contain additional ? 2-stabilizing elements, such as Nb, as is the case for most (semi)commercial, high-strength alloys. Therefore, recent efforts have concentrated on developing Ag-containing ?-TiAl alloys as oxidation-resistant coatings for high-strength titanium aluminides. Preliminary results using magnetron sputtering have shown that, due to the similarities in chemical and physical properties of the coating and base material, the Ag-containing material offers promising potential to be qualified as a coating material for reducing the oxidation-induced degradation of titanium aluminides.

  1. Ultrafine amorphous alloy particles

    Different techniques for the preparation of amorphous alloy particles are reviewed. Special attention is made to the studies of the preparation and the physical properties of ultrafine amorphous iron-boron and iron-carbon alloy particles. The properties of the ultrafine alloy particles are in most cases similar to those of bulk amorphous alloys of the same composition, e.g., the dependence of the hyperfine parameters on temperature and composition as well as Curie temperatures are similar. (orig.)

  2. PLUTONIUM-THORIUM ALLOYS

    Schonfeld, F.W.

    1959-09-15

    New plutonium-base binary alloys useful as liquid reactor fuel are described. The alloys consist of 50 to 98 at.% thorium with the remainder plutonium. The stated advantages of these alloys over unalloyed plutonium for reactor fuel use are easy fabrication, phase stability, and the accompanying advantuge of providing a means for converting Th/sup 232/ into U/sup 233/.

  3. Padrão eletroforético de proteínas resistentes ao calor em sementes de milho Electrophorectic pattern of the heat resistant proteins of corn seeds

    Solange Carvalho Barrios Roveri José

    2005-02-01

    Full Text Available Na aquisição e manutenção da tolerância à dessecação de sementes, há vários mecanismos envolvidos, entre eles a indução das proteínas resistentes ao calor. O objetivo deste trabalho foi avaliar mudanças no padrão eletroforético das proteínas resistentes ao calor de sementes de milho submetidas a alta temperatura de secagem, associando-as à sua tolerância. Foram utilizadas sementes de linhagens, híbridos simples e híbridos recíprocos colhidas com teor de água de aproximadamente 35% e secadas a 45°C. Sementes das linhagens secadas à sombra foram utilizadas como controle e sua qualidade fisiológica foi avaliada por meio do teste de germinação. As proteínas resistentes ao calor foram extraídas de eixos embrionários das sementes em tampão Tris HCl 0,05 M. Não foi possível determinar uma banda específica da fração das proteínas resistentes ao calor que possa servir como marcador da tolerância à alta temperatura de secagem. Houve estabilidade nos padrões de bandas das proteínas provenientes de sementes submetidas à secagem artificial e natural, mesmo quando foram observadas variações nos valores de germinação. Os padrões eletroforéticos das proteínas resistentes ao calor foram semelhantes entre as sementes híbridas e os respectivos recíprocos.Several mechanisms are involved in the acquisition and maintenance of desiccation tolerance by the seeds. One of these mechanisms is related to the induction of heat resitant proteins. The objective of this work was to evaluate changes in the electophorectic patterns of the heat resistant proteins of corn seeds submitted to high drying temperature associating their expression with drying tolerance. Seeds of breeding lines, simple hybrids and respective reciprocals hybrids were utilized. The seeds were harvested with approximately 35% of water content and dried at 45°C. Seeds of lines dried under shadow were used as control and the physiological quality was evaluated by germination test. The heat resistant proteins were extracted from embryonic axis of seeds in Tris-HCl 0.05 M buffer. It was not possible to determine a specific band of heat resistant proteins which can be of use as a molecular marker of tolerance to high drying temperature. There was stability in the patterns of the bands of proteins of seeds submitted to artificial drying compared to the ones after shadow drying even for the lines of high variation in the germination values. The electrophorectic patterns of the heat resistant proteins were similar for both the hybrid seeds and respective reciprocals.

  4. An irradiation test of heat-resistant ceramic composite materials (2). Interim report on post-irradiation examinations of the second and third preliminary test: 98M-41A, 99M-30A

    The Japan Atomic Energy Research Institute (JAERI) has been carrying out the research on radiation damage mechanism of heat-resistant ceramic composite materials, as one of the subjects of the innovative basic research on high temperature engineering using the High Temperature Engineering Test Reactor (HTTR). A series of preliminary irradiation tests is being made using the Japan Materials Testing Reactor (JMTR). The present report describes results of post-irradiation examinations (PIE) so far on specimens irradiated in the second and third capsule, designated 98M-41A and 99M-30A, to fast neutron fluencies of 1.0x1025 m-2 (E > 1 MeV) at temperatures of 973-1173K and 1273-1473K. The PIE were conducted as the fundamental statistic index of the diametral dimensions for irradiated specimen, irradiation induced dimensional change rate and thermal expansion rate. (author)

  5. F-Alloy: An Alloy Based Model Transformation Language

    Gammaitoni, Loïc; Kelsen, Pierre

    2015-01-01

    Model transformations are one of the core artifacts of a model-driven engineering approach. The relational logic language Alloy has been used in the past to verify properties of model transformations. In this paper we introduce the concept of functional Alloy modules. In essence a functional Alloy module can be viewed as an Alloy module representing a model transformation. We describe a sublanguage of Alloy called F-Alloy that allows the specification of functional Alloy modules. Module...

  6. Identificao de cultivares de milho, feijo, algodo e soja por meio de enzimas e protenas resistentes ao calor Cultivars identification of corn, bean, cotton and soybean using enzymes and heat-resistant proteins

    Mariney de Menezes

    2008-01-01

    Full Text Available Nesta pesquisa foram avaliados o polimorfismo e a estabilidade de isoenzimas e de protenas resistentes ao calor em sementes de cultivares de milho, feijo, algodo e soja, com diferentes nveis de qualidade fisiolgica. As isoenzimas ,lcool desidrogenase, catalase, esterase e superxido dismutase analisadas conjuntamente, foram eficientes na separao de oito cultivares de milho. Para as cultivares de feijo, pela enzima peroxidase foi possvel diferenciar a cultivar Carioca, no entanto, este padro mostrou-se varivel em sementes com baixa germinao. No foi possvel diferenciar as cultivares de algodo pelas enzimas esterase, superxido dismutase, diaforase e malato desidrogenase. A cultivar Conquista, de soja, foi diferenciada pelos sistemas enzimticos esterase e superxido dismutase e a 'BRS-154' pela esterase. Protenas resistentes ao calor so polimrficas e estveis para a identificao de cultivares de milho.In this study the polymorphism and stability of isoenzymes and heat-resistant proteins in corn, bean, cotton, and soybean seeds with different levels of physiological quality were evaluated. The alcohol dehydrogenase, catalase, esterase and superoxide dismutase enzymes and simultaneous analysis were effective in identifying eight corn cultivars. It was observed for the bean cultivars that the peroxidase enzyme allowed differentiation of the Carioca bean cultivar from the others but, the peroxidase enzyme pattern varied in seeds with low-germination percentage. The varieties of cotton could not be differentiated by esterase enzyme, superoxide dismutase, diaphorase and malate dehydrogenase. The Conquista soybean cultivar was separated by superoxide dismutase and esterase enzyme systems and BRS-154 was separated by esterase. Heat-resistant protein patterns showed polymorphism and were stable for corn cultivar identification.

  7. Determination of Lethality Rate Constants and D-Values for Heat-Resistant Bacillus Spores ATCC 29669 Exposed to Dry Heat from 125°C to 200°C

    Schubert, Wayne W.; Beaudet, Robert A.

    2011-04-01

    Exposing flight hardware to dry heat is a NASA-approved sterilization method for reducing microbial bioburden on spacecraft. The existing NASA specification only allows heating the flight hardware between 104°C and 125°C to reduce the number of viable microbes and bacterial spores. Also, the NASA specifications only allow a four log reduction by dry heat microbial reduction because very heat-resistant spores are presumed to exist in a diverse population (0.1%). The goal of this research was to obtain data at higher temperatures than 125°C for one of the most heat-resistant microorganisms discovered in a spacecraft assembly area. These data support expanding the NASA specifications to temperatures higher than 125°C and relaxing the four log reduction specification. Small stainless steel vessels with spores of the Bacillus strain ATCC 29669 were exposed to constant temperatures between 125°C and 200°C under both dry and ambient room humidity for set time durations. After exposures, the thermal spore exposure vessels were cooled and the remaining spores recovered and plated out. Survivor ratios, lethality rate constants, and D-values were determined at each temperature. The D-values for the spores exposed under dry humidity conditions were always found to be shorter than those under ambient humidity. The temperature dependence of the lethality rate constants was obtained by assuming that they obeyed Arrhenius behavior. The results are compared to those of B. atrophaeus ATCC 9372. In all cases, the D-values of ATCC 29669 are between 20 and 50 times longer than those of B. atrophaeus ATCC 9372.

  8. Optimization of the Mg–Al–Zn–Ca–Sr alloy composition based on the parameter A′ in the constitutive equation for the climb-controlled dislocation creep including the stacking fault energy

    In this study, calcium, Ca-, and strontium, Sr-added AZ91 magnesium alloys, which were composed of magnesium, Mg–9 wt.% aluminum, Al–0.8 wt.% zinc, Zn–x wt.% Ca–y wt.% Sr, were formulated and designated as AZXJ91xy alloys. The optimum composition of die-cast AZXJ alloys has been studied by micro-structural analysis and through the application of the constitutive equation of deformation behavior at elevated temperatures that includes the stacking fault energy. The normalized plots of the tensile test results of AZXJ alloys at 448 K by the constitutive equation of deformation behavior indicated that the deformation mechanism of the alloys was climb-controlled dislocation creep. The value of the constant A′ in the constitutive equation differs in the different AZXJ alloys, even though the effect of the solid solution of added elements, which is considered in the stacking fault energy term, was eliminated from A′. Using A′ as an indicator parameter of the creep resistance with the tensile strength at ambient temperature, the optimum composition of the creep-resistant Mg–Al–Zn–Ca–Sr alloy has been determined, and its creep resistance was comparable to those of known heat-resistant magnesium alloys.

  9. High frequency fatigue test of IN 718 alloy – microstructure and fractography evaluation

    J. Belan

    2015-01-01

    Full Text Available INCONEL alloy 718 is a high-strength, corrosion-resistant nickel chromium material used at -253 °C to 705 °C for production of heat resistant parts of aero jet engine mostly. The fatigue test provided on this kind materials were done via low frequency loading up to this time. Nowadays, needs of results at higher volume of loading cycles leads to high frequency loading with aim to shorten testing time. Fatigue test of experimental material was carried out at frequency 20 kHz with stress ration R = - 1 (push – pull at room temperature. It was found that this superalloy can still fracture after exceeding 108 cycles. Besides fatigue test were microstructural characterisation and scanning electron microscopy (SEM fractography evaluation done.

  10. A study on fretting fatigue life for the Inconel alloy 600 at high temperature

    Kwon, Jae-do [Department of Mechanical Engineering, Yeungnam University, Kyongsan (Korea, Republic of); Park, Dae-kyu [Graduate School of Mechanical Engineering, Yeungnam University, Kyongsan (Korea, Republic of); Woo, Seung-wan [Department of Mechanical Engineering, Yeungnam University, Kyongsan (Korea, Republic of); Yoon, Dong-hwan [Graduate School of Mechanical Engineering, Yeungnam University, Kyongsan (Korea, Republic of); Chung, Ilsup, E-mail: ilchung@yu.ac.k [Department of Mechanical Engineering, Yeungnam University, Kyongsan (Korea, Republic of)

    2010-10-15

    Fatigue tests of the Inconel 600, a type of nickel-chromium based heat resistant alloy used for steam generator tubes in nuclear power plants, were carried out. Temperature increase to 320 {sup o}C did not change the fatigue strength much, but the fretting condition caused a significant reduction in the fatigue strength. The reduction at 10{sup 7} cycles was about 70% for both of room and the high temperatures. An apparatus to realize the fretting condition has been developed and instrumented to measure the normal and friction forces. The bridge type of contact pad was fabricated of SUS 409 stainless steel. Fracture surfaces and wear scars were observed by electron microscope and the profiles of wear scar were measured by non-contact 3D-profiler.

  11. Oxidation of CoCrFeMnNi High Entropy Alloys

    Holcomb, Gordon R.; Tylczak, Joseph; Carney, Casey

    2015-06-01

    Eight model high entropy alloys (HEAs) in the CoCrFeMnNi family (including one alloy each in the CoCrFeNi and CoFeMnNi subfamilies) were made, prepared, and exposed to laboratory air for 1100 h at 650C and 750C. Two commercial alloys, nickel-base superalloy 230 (N06230) and austenitic stainless steel 304H (S30409), were simultaneously exposed for comparison. Mass change oxidation kinetics were measured and cross-sections of exposed samples were observed. Seven of these HEAs contained much more Mn (12-24 wt.%) than is found in commercial heat-resistant stainless steels and superalloys. The oxidation resistance of CoCrFeNi was excellent and comparable to 304H at 650C and only slightly worse at 750C. The thin oxide scale on CoCrFeNi was primarily Cr oxide (presumably Cr2O3) with some Mn oxide at the outer part of the scale. The CoCrFeMnNi HEAs all experienced more rapid oxidation than CoCrFeNi and, especially at 750C, experienced oxide scale spallation. The addition of Y in the alloy to lower S improved the oxidation resistance of these HEAs. Alloy CoFeMnNi, without Cr, experienced much higher oxidation rates and scale spallation than the Cr-containing alloys. A linear regression analysis of the log of the parabolic rate constant, log(kp), as functions of wt.% Cr and Mn found a good correlation for the compositional dependence of the oxidation rate constant, especially at 650C. Mn was found to be more detrimental increasing log(k p) than Cr was helpful reducing log(k p). If CoCrFeMnNi HEAs are to be used in high temperature oxidizing environments, then examining lower levels of Mn, while maintaining Cr levels, should be pursued.

  12. High strength alloys

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub

    2012-06-05

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  13. High strength alloys

    Maziasz, Phillip James [Oak Ridge, TN; Shingledecker, John Paul [Knoxville, TN; Santella, Michael Leonard [Knoxville, TN; Schneibel, Joachim Hugo [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Vinegar, Harold J [Bellaire, TX; John, Randy Carl [Houston, TX; Kim, Dong Sub [Sugar Land, TX

    2010-08-31

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tubular that is at least partially made from a material containing at least one of the metal alloys.

  14. Spark alloying of an AL9 alloy by hard alloys

    Kuptsov, S. G.; Fominykh, M. V.; Mukhinov, D. V.; Magomedova, R. S.; Nikonenko, E. A.

    2015-08-01

    The phase compositions of spark coatings of Kh12M steel with a VT1-0 (titanium) alloy and T15K6 and T30K4 hard alloys are studied. It is shown that the TiC titanium carbide forms in all cases and tungsten carbide decomposes with the formation of tungsten in a coating. These processes are intensified by increasing time, capacitance, and frequency. The surface hardness, the sample weight, and the white layer thickness increase monotonically.

  15. Creep Resistant Zinc Alloy

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  16. Biocompatibility of dental alloys

    Braemer, W. [Heraeus Kulzer GmbH and Co. KG, Hanau (Germany)

    2001-10-01

    Modern dental alloys have been used for 50 years to produce prosthetic dental restorations. Generally, the crowns and frames of a prosthesis are prepared in dental alloys, and then veneered by feldspar ceramics or composites. In use, the alloys are exposed to the corrosive influence of saliva and bacteria. Metallic dental materials can be classified as precious and non-precious alloys. Precious alloys consist of gold, platinum, and small amounts of non-precious components such as copper, tin, or zinc. The non-precious alloys are based on either nickel or cobalt, alloyed with chrome, molybdenum, manganese, etc. Titanium is used as Grade 2 quality for dental purposes. As well as the dental casting alloys, high purity electroplated gold (99.8 wt.-%) is used in dental technology. This review discusses the corrosion behavior of metallic dental materials with saliva in ''in vitro'' tests and the influence of alloy components on bacteria (Lactobacillus casei and Streptococcus mutans). The test results show that alloys with high gold content, cobalt-based alloys, titanium, and electroplated gold are suitable for use as dental materials. (orig.)

  17. The DynAlloy Visualizer

    Bendersky, Pablo; Galeotti, Juan Pablo; Garbervetsky, Diego

    2014-01-01

    We present an extension to the DynAlloy tool to navigate DynAlloy counterexamples: the DynAlloy Visualizer. The user interface mimics the functionality of a programming language debugger. Without this tool, a DynAlloy user is forced to deal with the internals of the Alloy intermediate representation in order to debug a flaw in her model.

  18. A study of kinetics of formation, structure, composition, and properties of electrospark coatings of modified electrode materials on the basis of TiC-KhN70Yu applied on OT4-1 titanium alloy

    The effect of nanodispersed additives (ZrO2, Al2O3, W, WC, WC-Co, NbC, Si2N4) on mass transfer of SHS-electrode materials on the basis of TiC-KhN70Yu was studied. A complex of investigations of electrospark coatings on OT4-1 alloy was carried out. An optimum mode of application of ESA-coatings was found using new modified electrode materials in the HF-plant. It was established that introduction of nanodispersed component into the electrode material promotes increasing mass transfer, thickness growth, uniformity, microhardness, and heat resistance of ESA-coatings

  19. Catalyst Alloys Processing

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  20. Amorphous metal alloy

    Wang, R.; Merz, M.D.

    1980-04-09

    Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.

  1. Superplasticity in titanium alloys

    J. Sieniawski; Motyka, M.

    2007-01-01

    Purpose: The paper reports characteristic of superplasticity phenomenon in titanium alloys and possibility of its applications.Design/methodology/approach: The main objective of the paper is to show features of superplastic forming of titanium alloys and current research trends aiming at widespread application of this technology.Findings: In the paper characteristic of selected superplastic titanium alloys was presented. The effect of microstructural parameters on superplasticity was consider...

  2. Characterization of Alloys with Potential for Application in Cable-in-Conduit Conductors for High-Field Superconducting Magnets

    Since the introduction of the cable-in-conduit conductor (CICC) concept, a variety of alloys have been proposed for fabricating the jacket. The jacket provides primary containment of the supercritical helium coolant and is typically also the primary structural component for the magnet. These functions create requirements for strength, toughness, weldability, and fabricability in tubular form. When the CICC uses Nb3Sn, there are additional requirements to accommodate the manufacturing and heat-treatment processes for the superconductor as well as its strain-sensitive performance during operation. Both of the present favorite jacket alloys, Incoloy 908 and modified (ultra-low carbon) 316LN, have both demonstrated acceptable functionality as well as a few undesirable features. In this paper, we present data from cryogenic mechanical tests on a group of heat-resistant, high-strength superalloys that appear to offer equal or better mechanical performance (e.g. strength, toughness, and modulus) while mitigating the undesirable aspects (e.g. SAGBO in the case of I908 and thermal-expansion mismatch with Nb3Sn in the case of 316LN). Data are presented for each alloy in the as-received and aged conditions. These alloys are presently being considered as candidates for use in the next-generation hybrid magnet for the NHMFL but may also be of interest to the fusion and energy storage communities

  3. Effect of Cu addition on microstructure and properties of Mg-10Zn-5Al-0.1Sb high zinc magnesium alloy

    You Zhiyong

    2012-02-01

    Full Text Available To improve the strength, hardness and heat resistance of Mg-Zn based alloys, the effects of Cu addition on the as-cast microstructure and mechanical properties of Mg-10Zn-5Al-0.1Sb high zinc magnesium alloy were investigated by means of Brinell hardness measurement, scanning electron microscopy (SEM, energy dispersive spectroscopy (EDS, XRD and tensile tests at room and elevated temperatures. The results show that the microstructure of as-cast Mg-10Zn-5Al-0.1Sb alloy is composed of ?-Mg, t-Mg32(Al, Zn49, ?-Al2Mg5Zn2 and Mg3Sb2 phases. The morphologies of these phases in the Cu-containing alloys change from semi-continuous long strip to black herringbone as well as particle-like shapes with increasing Cu content. When the addition of Cu is over 1.0wt.%, the formation of a new thermally-stable Mg2Cu phase can be observed. The Brinell hardness, room temperature and elevated temperature strengths firstly increase and then decrease as the Cu content increases. Among the Cu-containing alloys, the alloy with the addition of 2.0wt.% Cu exhibits the optimum mechanical properties. Its hardness and strengths at room and elevated temperatures are 79.35 HB, 190 MPa and 160 MPa, which are increased by 9.65%, 21.1% and 14.3%, respectively compared with those of the Cu-free one. After T6 heat treatment, the strengths at room and elevated temperatures are improved by 20% and 10%, respectively compared with those of the as-cast alloy. This research results provide a new way for strengthening of magnesium alloys at room and elevated temperatures, and a method of producing thermally-stable Mg-10Zn-5Al based high zinc magnesium alloys.

  4. Advances in titanium alloys

    As described above, new developments in the aerospace market are focusing on higher temperature alloys for jet engine components and higher strength/toughness alloys for airframe applications. Conventional alloys for engines have reached their maximum useful temperature of about 1000 F (540 C) because of oxidation resistance requirements. IMI 834 and Ti-1100 advanced alloys show some improvement, however, the major improvement appears to be in gamma titanium aluminides which could extend the maximum usage temperature to about 1500 F (815 C). This puts titanium alloys in a competitive position to replace nickel-base superalloys. Advanced airframe alloys such as Ti-6-22-22S, Beta CTM, Ti-15-333 and Ti-10-2-3 with higher strength than conventional Ti-6-4 are being utilized in significantly greater quantities, both in military and commercial applications. These alloys offer improved strength with little or no sacrifice in toughness and improved formability, in some cases. Advanced industrial alloys are being developed for improved corrosion resistance in more reducing and higher temperature environments such as those encountered in sour gas wells. Efforts are focused on small precious metal additions to optimize corrosion performance for specific applications at a modest increase in cost. As these applications develop, the usage of titanium alloys for industrial markets should steadily increase to approach that for aerospace applications. (orig.)

  5. Yttrium containing alloys

    A process for the production of alloys containing iron, chromium, aluminium and yttrium and/or rare earth metal or metals is described in which yttrium and/or rare earth metal or metals is added to a melt in the form of a master alloy having a melting point of less than 10000C. (author)

  6. Thermofluency in zirconium alloys

    A summary is presented about the theoretical and experimental results obtained at present in thermofluency under radiation in zirconium alloys. The phenomenon of thermofluency is presented in a general form, underlining the thermofluency at high temperature because this phenomenon is similar to the thermofluency under radiation, which ocurrs in zirconium alloys into the operating reactor. (author)

  7. Neutron-absorbing alloy

    The composition of the proposed neutron absorbing alloy varies within the following limits: 1-20 wt.-% In, 0,5-15 wt.-% Sm, 5-18 wt.-% Hf, 47-93,5 wt.-% Ni. Three examples are given with characteristic values. The alloy is to be used in automatic control and emergency protection systems of nuclear reactors. (UW/LH)

  8. Aluminum battery alloys

    Thompson, David S. (Richmond, VA); Scott, Darwin H. (Mechanicsville, VA)

    1985-01-01

    Aluminum alloys suitable for use as anode structures in electrochemical cs are disclosed. These alloys include iron levels higher than previously felt possible, due to the presence of controlled amounts of manganese, with possible additions of magnesium and controlled amounts of gallium.

  9. Copper-tantalum alloy

    Schmidt, Frederick A. (Ames, IA); Verhoeven, John D. (Ames, IA); Gibson, Edwin D. (Ames, IA)

    1986-07-15

    A tantalum-copper alloy can be made by preparing a consumable electrode consisting of an elongated copper billet containing at least two spaced apart tantalum rods extending longitudinally the length of the billet. The electrode is placed in a dc arc furnace and melted under conditions which co-melt the copper and tantalum to form the alloy.

  10. Magnetostrictive nickel base alloys

    The ways of optimization of magnetostrictive alloys on the Ni-4%Co base are under consideration. A number of binary and ternary alloys of the Ni-Co-Mn system were prepared with variations of Co and Mn contents in the range of 0-6% at intervals of 2%. Measurements of magnetic anisotropy and magnetostriction were carried out on the ribbons produced by hot and cold rolling and then annealed. On the basis of data obtained three new alloys for electroacoustic applications are proposed: Ni-3.5%Co-1%Mn; Ni-3.25%Co-3%W; a cobalt-free alloy NMGT. THe alloys proposed have acoustic properties comparable with those of conventional materials and surpass the latter in strength and corrosion resistance. 10 refs., 2 figs., 1 tab

  11. Alloys in energy development

    The development of new and advanced energy systems often requires the tailoring of new alloys or alloy combinations to meet the novel and often stringent requirements of those systems. Longer life at higher temperatures and stresses in aggressive environments is the most common goal. Alloy theory helps in achieving this goal by suggesting uses of multiphase systems and intermediate phases, where solid solutions were traditionally used. However, the use of materials under non-equilibrium conditions is now quite common - as with rapidly solidified metals - and the application of alloy theory must be modified accordingly. Under certain conditions, as in a reactor core, the rate of approach to equilibrium will be modified; sometimes a quasi-equilibrium is established. Thus an alloy may exhibit enhanced general diffusion at the same time as precipitate particles are being dispersed and solute atoms are being carried to vacancy sinks. We are approaching an understanding of these processes and can begin to model these complex systems

  12. Ultrahigh temperature intermetallic alloys

    Brady, M.P.; Zhu, J.H.; Liu, C.T.; Tortorelli, P.F.; Wright, J.L.; Carmichael, C.A.; Walker, L.R. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

    1997-12-01

    A new family of Cr-Cr{sub 2}X based alloys with fabricability, mechanical properties, and oxidation resistance superior to previously developed Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys has been identified. The new alloys can be arc-melted/cast without cracking, and exhibit excellent room temperature and high-temperature tensile strengths. Preliminary evaluation of oxidation behavior at 1100 C in air indicates that the new Cr-Cr{sub 2}X based alloys form an adherent chromia-based scale. Under similar conditions, Cr-Cr{sub 2}Nb and Cr-Cr{sub 2}Zr based alloys suffer from extensive scale spallation.

  13. Nanocrystalline alloy hydrides formed by mechanical alloying

    This article presents the work carried out on nanocrystalline Mg2Ni, LaNi5, ZrV2 and TiFe phases, which were prepared by mechanical alloying (MA) and then annealing. XRD analysis showed that, after ∼40 h milling the studied alloys have decomposed into amorphous phases. Following annealing in high purity argon, XRD confirmed the formation of ordered materials. These alloys were used as active materials for the negative electrodes of an alkaline, rechargeable nickel-metal hydride (Ni-MHx) batteries . The electrochemical results show the substantial difference between the nanocrystalline and the amorphous powders. For example, in nanocrystalline TiFe0.5Ni0.5 powder discharging capacities up to 125 mA h g-1 (at 40 mA g-1 discharge current) have been measured. MA process has recently emerged as a novel interesting electrochemical properties. (author)

  14. Synthesizing Aluminum alloys by double mechanical alloying

    Froyen, L.; Delaey, L.; Niu, X. P.; Le Brun, P.; Peytour, C.

    1995-03-01

    A new synthesis technique, namely double mechanical alloying (dMA), has been developed to fabricate aluminum alloys containing the finely distributed intermetallic compounds and inert dispersoids Al4C3 and Al2O3 The technique consists mainly of three steps: a primary milling stage of elemental powders (MAI) followed by a heat treatment to promote the formation of intermetallic phases, a secondary milling stage (MA2) to refine the microstructure, and consolidation of the produced powders. The results of mechanical and tribological properties of the resulting materials indicate that the dMA is a promising technique for the fabrication of aluminum alloys for applications requiring wear resistance and high-temperature performance.

  15. FRAUD/SABOTAGE Killing Nuclear-Reactors Need Modeling!!!: ``Super'' alloys GENERIC ENDEMIC Wigner's-Disease/.../IN-stability: Ethics? SHMETHICS!!!

    O'Grady, Joseph; Bument, Arlden; Siegel, Edward

    2011-03-01

    Carbides solid-state chemistry domination of old/new nuclear-reactors/spent-fuel-casks/refineries/jet/missile/rocket-engines is austenitic/FCC Ni/Fe-based (so miscalled)"super"alloys(182/82;Hastelloy-X,600,304/304L-SSs,...690!!!) GENERIC ENDEMIC EXTANT detrimental(synonyms): Wigner's-disease(WD) [J.Appl.Phys.17,857 (46)]/Ostwald-ripening/spinodal-decomposition/overageing-embrittlement/thermal-leading-to-mechanical(TLTM)-INstability: Mayo[Google: fLeaksCouldKill > ; - Siegel [ J . Mag . Mag . Mtls . 7 , 312 (78) = atflickr . comsearchonGiant - Magnotoresistance [Fert" [PRL(1988)]-"Gruenberg"[PRL(1989)] 2007-Nobel]necessitating NRC inspections on 40+25=65 Westin"KL"ouse PWRs(12/2006)]-Lai [Met.Trans.AIME, 9A,827(78)]-Sabol-Stickler[Phys.Stat.Sol.(70)]-Ashpahani[ Intl.Conf. Hydrogen in Metals, Paris(1977]-Russell [Prog.Mtls.Sci.(1983)]-Pollard [last UCS rept.(9/1995)]-Lofaro [BNL/DOE/NRC Repts.]-Pringle [ Nuclear-Power:From Physics to Politics(1979)]-Hoffman [animatedsoftware.com], what DOE/NRC MISlabels as "butt-welds" "stress-corrosion cracking" endpoint's ROOT-CAUSE ULTIMATE-ORIGIN is WD overageing-embrittlement caused brittle-fracture cracking from early/ongoing AEC/DOE-n"u"tional-la"v"atories sabotage!!!

  16. FRAUD/SABOTAGE Killing Nuclear-Reactors!!! ``Super"alloys GENERIC ENDEMIC Wigner's-Disease IN-stability!!!

    Asphahani, Aziz; Siegel, Sidney; Siegel, Edward

    2010-03-01

    Siegel [[J.Mag.Mag.Mtls.7,312(78); PSS(a)11,45(72); Semis.& Insuls.5(79)] (at: ORNL, ANS, Westin``KL"ouse, PSEG, IAEA, ABB) warning of old/new nuclear-reactors/spent-fuel-casks/refineries/ jet/missile/rocket-engines austenitic/FCC Ni/Fe-based (so MIS- called)``super"alloys(182/82;Hastelloy-X; 600;304/304L-SSs; 690 !!!) GENERIC ENDEMIC EXTANT detrimental(synonyms): Wigner's- diseas(WD)[J.Appl.Phys.17,857(46)]; Ostwald-ripening; spinodal- decomposition; overageing-embrittlement; thermomechanical- INstability: Mayo[Google: ``If Leaks Could Kill"; at flickr.com search on ``Giant-Magnotoresistance"; find: [Siegel<<<``Fert"(88) 2007-Nobel/Wolf/Japan-prizes]necessitating NRC inspections on 40+25=65 Westin``KL"ouse PWRs(12/06)]; Lai[Met.Trans.AIME,9A,827 (78)]-Sabol-Stickler[PSS(70)]; Ashpahani[Intl.Conf. H in Metals (77)]; Russell[Prog. Mtls.Sci.(83)]; Pollard[last UCS rept. (9/95)]; Lofaro[BNL/DOE/NRC Repts.]; Pringle[Nuclear-Power:From Physics to Politics(79)]; Hoffman[animatedsoftware.com],...what DOE/NRC MISlabels as ``butt-welds" ``stress-corrosion cracking" endpoint's ROOT-CAUSE ULTIMATE-ORIGIN is WD overageing-embrit- tlement caused brittle-fracture cracking from early/ongoing AEC/DOE-n``u''tional-la``v''atories sabotage!!!

  17. Titanium nitride strengthened alloys

    A titanium containing stainless steel or a nickel base alloy containing titanium and chromium is atomised in a nitrogen atmosphere and the nitrided product blended with the same alloy atomised in argon, in proportions to give an overall nitrogen content equal to that required for stoichiometric titanium nitride in the blend. The blended powder is then homogenised at a temperature at which nitrides of iron and/or chromium dissociate and the free nitrogen reacts with titanium in the argon-atomised powder to produce a powder which can be formed into artifacts, by hot isostatic pressing e.g. for nuclear reactors, of titanium nitride strengthened alloy. (author)

  18. Technetium and technetium alloys

    This report presents the results of a literature survey on technetium and technetium alloys. The literature has been searched through 1993. The survey was focused on technetium and (binary cubic) technetium alloys, but other important information on technetium has not been omitted from this survey. This report has been written with the aim to collect more information about phase systems which could be of importance in the transmutation process by neutrons of technetium. With the information presented in this report, it should be possible to select a suitable technetium alloy for further investigation regarding to the transmutation process. (orig.)

  19. Heat resistance of fungi from soil.

    Jesenská, Z; Piecková, E; Bernát, D

    1993-08-01

    The survival of fungi from soil samples has been investigated after exposure to temperatures of 60, 70, 80 and 90 degrees C in Sabouraud agar. The least resistant fungi surviving 60 degrees C for 60 min were the Aspergillus (A.) niger group, Chaetomium spp, Penicillium spp, and Scytalidium lignicola. None of these survived 70 degrees C for 10 min. The next group surviving 70 degrees C for 60 min included the A. glaucus group, Byssochlamys nivea, Dichotomomyces cejpii, Gelasinospora spp, Rhizoctonium spp, and Talaromyces flavus; they did not survive 80 degrees C for 10 min. At 80 degrees C for 60 min, survival was seen for Aspergillus fumigatus, Aspergillus nidulans, Eupenicillium baarnense and Ulocladium spp; they did not survive 10 min at 90 degrees C. Acremonium sclerotigenum, Aspergillus ochraceus, Botryotrichum piluliferum, Byssochlamys fulva, Gilmaniella humicola, Neosartorya fischeri, Nodulisporium sp. and Talaromyces avellaneus survived heat treatment at 90 degrees C for 10 min and longer time with the two last being the most resistant. The phenomen of activation of dormant spores by thermal shock was not apparent. PMID:8217516

  20. Influence of ceramics structure on heat resistance

    Effect of structure on thermal and strength properties of ceramics on corundum base (microlyte TsM-332) and zirconium dioxide stabilized with yttrium oxide containing electroconducting additions-zirconium diboride and yttrium chromite, has been studied. It is shown that laminated corundum ceramics as to thermal stability by almost three times surpasses ceramics with fine-disperse structure. It is established, that laminated structure formation can ensure an increase of the material thermal stability as well as a high density, which is important for electrode and insulation materials for MHD-installation