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Sample records for heat-resistant alloy hastelloy

  1. Corrosion resistance of alloys of Hastelloy in chloroaluminate melts

    Karpov, V. V.; Bazhenov, A. V.; Abramov, A. V.; Polovov, I. B.; Rebrin, O. I.

    2015-01-01

    The corrosion of Hastelloy S, Hastelloy X, Haynes 230, Hastelloy N, Hastelloy G35 and Hastelloy C2000 alloys was studied in KCl-AlCl3 melts at 550°С. The rates and the mechanisms of corrosion of the studied materials were determined. The processes taking place during the interaction between alloys and chloroaluminate melts were investigated.

  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. 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

  6. Machining of high alloy steels and heat resistant alloys

    The peculiarities of machining high alloy steels and heat resistant alloys on the base of nickel by cutting are described. The factors worsening the machining of heat resistant materials, namely, the low heat conductivity, strong reverting and high wearing capability, are pointed out. The resign and materials of cutting instruments, providing for high quality machining of heat resistant steels and alloys, are considered. The necessity of regulating thermal processes during cutting with cutting fluids and other coolants (e.g. air with a negative temperature) is noted. The recommended modes of cutting are presented. The efficiency of the conveyer-type method for sawing products and forged intermediate articles is demonstrated by the example of 5KhNM steel

  7. Hydrogen permeation through iron, nickel, and heat resisting alloys at elevated temperatures

    Hydrogen permeabilities of several metals and alloys were measured over the temperature range of 200 - 10000C and some factors affecting the hydrogen permeability were discussed. Materials studied were iron, nickel, 80Ni-20Cr alloy, 50Fe-30Ni-20Cr alloy, HK 40, Incoloy 800, Hastelloy X, and Inconel 600. The hydrogen permeability of nickel was proportional to the square root of the pressure and inversely proportional to the membrane thickness. The activation energy and pre-exponential factor for the hydrogen permeation through these metals and alloys were derived from the temperature coefficient. The hydrogen permeability of nickel was larger than that of iron (γ), and the permeabilities of the heat resisting alloys were between those of nickel and iron (γ). There was a close correlation between the hydrogen permeability and nickel content in the alloys, that is, the permeability increased with the increase of the nickel content in the alloys. The formation of the oxide film on the alloy surface in wet hydrogen resulted in a remarkable reduction of the hydrogen permeability at elevated temperatures. (auth.)

  8. 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 400-900?C. 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...

  9. Heat resistance of multicomponent coatings on the niobium alloys

    Increase in heat resistance of niobium and its alloys by means of diffusion saturation with aluminium together with the elements reducing its mobility, i.e. chromium and silicon is studied. It is shown that the Cr-Al coating can be used for protection of niobium alloys at the temperatures below 1000 deg C or as a sublayer for silicide coatings. Simultaneous saturation with chromium, aluminium and silicon results in formation of a coating consisting of three layers, heat resistance of which increases considerably as compared to the one observed in the case of two-component saturation with chromium and aluminium. The study of the samples with the Cr-Al-Si coating has also shown that oxidation of alloys in this case proceeds less intensely. Possibility of the coating application for practical purposes for niobium alloys protection from oxidation in the air at high temperatures is shown

  10. 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.

  11. 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)

  12. Improvement of niobium alloy heat resistance by diffusion coatings

    Changes in the 5VTTs, 5VMTs and 5VMTs4 niobium alloys taking place while interacting with oxidizing medium, were studied along with the possibility to improve heat resistance of the alloys by diffusion coatings laid out from liquid-metal solution. Single-component coatings of Zr, Re, Be, Ni, Y and two-layer ones of Zr-Rd, Re-Rd, Re-Be, Rd-Be were laid. The Zr, Re, Zr-Rd and Re-Rd coatings are shown to provide for the protection of the 5 VTTs alloy from oxidation in vacuum at 1050 deg C. The most effective protection of the 5 VMTs alloy is provided in air by single-layer coatings of Be, Ni, Y, and two-layer ones of Rd-Be and Re-Be. It is noted that Re-containing coatings improve the strength but reduce the plasticity of niobium alloy as a result of alloying due to a significant diffusion mobility of rhenium in niobium

  13. Investigation on corrosion resistance of Hastelloy N alloy after He+ ion irradiation

    Background: The invalidation problems of irradiated Hastelloy N alloy caused by high temperature, intense irradiation and severe corrosion are the key factors to the service life of structural materials of molten salt reactor (MSR). Purpose: The aim is to investigate the effect of absorbed dose on the corrosion resistance of Hastelloy N alloy. Methods: Hastelloy N alloy was irradiated by 4.5-MeV He+ ions, and the absorbed doses were 0 He+·cm-2, 1x1015 He+·cm-2, 5×1015 He+·cm-2 and 1×1016 He+·cm-2 respectively. The virgin and irradiated specimens were immersed into molten fluoride salts at 700℃ for 300 h. Then the corroded specimens were imaged by scanning electron microscopy and analyzed by synchrotron radiation microbeam X-ray fluorescence (μ-XRF). Results: The weight-loss results showed that the corrosion generally correlated with the absorbed dose of the alloy. The μ-XRF results indicated that the corrosion was mainly due to the dealloying of alloying element Cr in the matrix. Conclusion: The density of dislocations of Hastelloy N alloy increased with the absorbed dose, which acted as quick paths for Cr element diffusion, and the diffusion of element Cr out of matrix became easier. Finally became weak of the corrosion resistance of Hastelloy N alloy. (authors)

  14. Microstructure and properties of 2618-Ti heat resistant aluminum alloy

    王建华; 易丹青; 王斌

    2003-01-01

    The mechanical properties of alloy 2618 with 0.5%(mass fraction) titanium and its microstructures in different states such as as-cast and quenching-aging were investigated. Titanium was added into the alloy with Al-5%Ti master alloy that was extruded severely. Al3Ti particles in the microstructure of cast alloy 2618-Ti are very small because those of master alloy are also small. When titanium is used as an alloying element, it does not affect the morphology of Al9FeNi phase in cast alloy, but decreases the grain size of as-cast alloy remarkably. The grain size of quenching-aging alloy 2618 decreases apparently due to the existence of a great deal of dispersive Al3Ti particles. Adding 0.5%Ti has no effect on the room temperature tensile properties of alloy 2618, but apparently increases the elevated temperature instantaneous tensile properties and that of the alloy which is exposed at 250 ℃ for 100 h.

  15. Heat-resisting alloys for hard surfacing and sealing pad welding

    R.O. Wielgosz

    2010-07-01

    Full Text Available The paper deals with heat-resisting alloys used to harden surfaces of elements operating in increased temperatures. It also deals with alloysused to seal cooperating surfaces of elements operating in the conditions of increased temperatures and aggressive utilities. Application methods and properties of thus obtained layers have been presented and adhesion of layers with matrix material has been assessed.

  16. Heat-resisting alloys for hard surfacing and sealing pad welding

    R.O. Wielgosz

    2010-01-01

    The paper deals with heat-resisting alloys used to harden surfaces of elements operating in increased temperatures. It also deals with alloysused to seal cooperating surfaces of elements operating in the conditions of increased temperatures and aggressive utilities. Application methods and properties of thus obtained layers have been presented and adhesion of layers with matrix material has been assessed.

  17. Geometrical product specifications heat-resistant cobalt cast alloy

    Lyubimov V.

    2007-01-01

    Full Text Available Geometrical product specification MAR-M509 cast cobalt alloy depend beginning temperature of multilayer ceramic shell moulds (MCS. It has found that go down temperature of MCS from 1000°C to 200°C, the increase surface roughness and its amplitude parameters: Sa, Sz, St, Sq, Sp and Sv.

  18. Geometrical product specifications heat-resistant cobalt cast alloy

    Lyubimov V.; Opiekun Z.; Bonk C.

    2007-01-01

    Geometrical product specification MAR-M509 cast cobalt alloy depend beginning temperature of multilayer ceramic shell moulds (MCS). It has found that go down temperature of MCS from 1000°C to 200°C, the increase surface roughness and its amplitude parameters: Sa, Sz, St, Sq, Sp and Sv.

  19. 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.)

  20. 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.

  1. 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

  2. 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

  3. Corrosion behavior of Hastelloy-N alloys in molten salt fluoride in Ar gas or in air

    The effects of air on the corrosion of Hastelloy-N alloys in molten salt coolant containing fission product elements were investigated to determine the safety of structural materials in high-temperature reactors cooled with fluoride salt. Corrosion tests of Hastelloy-N in the molten fluoride salt FLiNaK in an alumina crucible and a graphite crucible under argon gas or air were performed at 773–923 K for 100 h. The depth of corrosive attack, as well as the extent of chromium and molybdenum depletion, increased with increasing temperature. The extent of Hastelloy-N corrosion in molten salt under air was significantly greater than under argon gas. The effect of adding the impurity cesium iodide to molten salt containing nuclear waste fuel on the corrosion behavior was negligible. (author)

  4. 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.)

  5. Oxidation of Hastelloy-XR Alloy for Corrosion-Resistant Glass-Coating

    2003-01-01

    The oxidation behavior of Hastelloy-XR alloy was investigated to obtain the optimum surface condition for corrosion-resistant glass-coatings. The surface morphology of oxide scales changed significantly with variation of temperatureand oxygen partial pressure (Po2). The oxidation kinetics was mainly parabolic independent of oxidation conditions.The oxide scales were consisted of inner Cr2O3 and outer spinel layers. The phase component of spinel layers wereMn1.5Cr1.5O4 and (Mn,Ni)(Cr,Fe)2O4 for the oxygen partial pressures Po2 <10 kPa and Po2>10 kPa, respectively.The optimum oxidation condition to obtain an oxide scale for well-adhered glass-coating to the substrate was 1248 Kand Po2 =0.01 kPa for the oxidation time of 43 ks.

  6. 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)

  7. 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.

  8. SEM, EDS, EPMA-WDS and EBSD characterization of carbides in HP type heat resistant alloys

    The microstructure of centrifugally cast heat resistant alloys of the HP-series (Fe-35Ni-25Cr-0.4C, wt.%) contains several minor phases, like carbides (M7C3, M23C6 and MC). Several alloys are characterized by means of scanning electron microscopy in back-scattered electron imaging and energy dispersive spectroscopy, of electron probe micro-analysis by X-ray wavelength dispersive spectroscopy, and of electron back-scattered diffraction. On the one hand, scanning electron microscopy imaging in the back-scattered mode, associated with energy dispersive spectroscopy analysis and electron back-scattered diffraction, can lead to the identification of all phases, but with a lack of accuracy in certain cases. On the other hand, electron probe micro-analysis by X-ray wavelength dispersive spectroscopy alone can always provide a strict identification of all phases, with additional precise information on phase composition, including for light elements, which is important in the case of carbides

  9. Corrosion Behavior of Au, Hastelloy C-276 Alloy and Monel 400 Alloy in Molten Lithium Fluoride

    WANG; Chang-shui; GUO; Jun-kang

    2013-01-01

    For searching better corrosion-resistant material in high temperature,we investigated the corrosion behavior of Au,Haynes C-276 alloy and Monel 400 alloy in molten lithium fluoride at 950℃.The corrosion products and fine structures of the corroded specimens were characterized by inductively coupled plasma mass spectrometry(ICP-MS),scanning electron microscope(SEM),energy dispersive

  10. Effects of product form and boron addition on the creep damage in the modified Hastelloy X alloys in a simulated HTGR helium gas environment

    The present paper investigates early-stage-creep damage of Hastelloy XR and XR-II alloys, modified versions of Hastelloy X alloy, which have been developed in Japan as most promising candidate structural alloys for Japanese high-temperature gas-cooled reactors (HTGRs). Creep tests were made on Hastelloy XR forging, tube and XR-II tube at 1,123 to 1,273 K in a simulated HTGR helium gas environment. The tests were interrupted at different strain levels of up to 5 % in order to evaluate creep damage via intergranular voids. The void sizes along grain boundaries and the A-parameter, the ratio of the number of damaged grain boundaries, on which one or more voids are found, to that of the total grain boundaries observed are used in order to evaluate creep damage. Statistical analysis of the A-parameter as well as the void sizes reveals that the values of the parameter show wide variations and follow the Weibull distribution, reflecting spatial randomness of the voids. The void sizes along grain boundaries, on the other hand, follow the log-normal distribution. The maximum void size dmax and the mean value of the A-parameter Am are calculated and plotted against interruption creep strain εint. The resultant dmax vs. εint and Am vs. εint diagrams show that Hastelloy XR forging had suffered more damage than Hastelloy XR tube; nevertheless, the forging has longer interruption life, or the time to reach a given interruption creep strain. The result indicates that grains may have been deformed more easily in Hastelloy XR in the form of tube than in the form of forging. The diagrams also imply that the addition of boron has suppressed the nucleation as well as the growth of voids and thus has brought about longer interruption life of Hastelloy XR-II. (author)

  11. 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/Δm, 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 (σd) 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)

  12. 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%.

  13. Heat treating of a lamellar eutectic alloy (gamma/gamma prime + delta). [heat resistant alloys

    Tewari, S. N.; Dreshfield, R. L.

    1976-01-01

    Eutectic superalloys are being developed at several laboratories for application as aircraft gas turbine airfoils. One such alloy was subjected to several heat treatments to determine if its mechanical properties could be improved. It was found that by partially dissolving the alloy at 1210 C and then aging at 900 C the tensile strength can be increased about 12 percent at temperatures up to 900 C. At 1040 C no change in tensile strength was observed. Times to rupture were measured between 760 and 1040 C and were essentially the same or greater than for as-grown material. Tensile and rupture ductility of the alloy are reduced by heat treatment. Photographs of the microstructure are shown.

  14. 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.

  15. Creep behavior for Hastelloy-XR

    Creep-rupture tests for Hastelloy-XR, a Ni-base heat resistent alloy, were conducted in air at the temperature of 650 to 900 deg C. Times to rupture ranged from 1000 to 16000 h. As results of tests, creep curves were observed to vary depending on both temperature and stress, particularly on temperature. Namely, they showed typical classical shapes consisting of primary, secondary and tertiary creep at 650 to 700 deg C. The regions of primary and secondary creep decreased gradually as the temperature became higher and in one case of 900 deg C and high stress, only tertiary creep was observed. Metallurgical observation by optical microscope showed the similar inclination. Some differences were found concerning rupture morphology and void shape between temperatures below 750 deg C and above 850 deg C. (author)

  16. 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%.

  17. Increase of heat resistance of niobium and its alloys using alumotitanizing

    The mechanism of codeposition of titanium and aluminium on niobium in molten salt media and heat resistance properties of the coatings obtained are studied. It is shown that aluminium-titanium coatings on niobium are suitable only as a substrate for other coatings. As an independent heat resistant coating the aluminium-titanium layers TiAl3 and TiAl containing surface phases can be used

  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. 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.)

  20. 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.)

  1. 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.

  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. 9%Cr heat resistant steels: Alloy design, microstructure evolution and creep response at 650 deg. C

    Highlights: → 9Cr alloys with varying Ti and C contents were designed, produced and crept at 650 deg. C. → Sub-grain and precipitate distribution and evolution investigated by STEM-HAADF. → Correlations between microstructure evolution and mechanical properties were studied. → Coarsening of sub-grain size was larger for Ti-containing 9Cr alloys. → 9Cr alloy with low C and no Ti showed the highest creep strength of all studied alloys. - Abstract: In this work 9%Cr alloys were designed supported by computational thermodynamic methods. 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 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. For Ti-containing alloys the precipitation of nano-sized Ti-rich MX carbonitrides was observed. The microstructure evolution (sub-grain and particle size) during creep at 650 deg. C/100 MPa 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.

  5. Obtaining of plasma sprayed heat resistant coatings for niobium and its alloys

    The paper is concerned with a possibility to obtain a hot-resistant molybdenum disilicide base coating by the plasma method. It is shown that preliminary boriding of sprayed molybdenum disilicide powders permits oxygen penetration to the substrate to be removed due to formation of fluid oxide SiO2-B2O3 film in oxidative media. It is determined that plasma-sprayed coatings produced from such powders are characterized by low temperature of vitrification (700-1000 deg C), porosity absence, strong cohesion of particles, high heat-resistance

  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

  7. 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

  8. 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.)

  9. Production of heat resisting silicon-titanium coatings on 5VMTs niobium alloy in fusible metal environment

    Oxidation of diffusion Si-Ti coatings on 5VMTs niobium alloy during aging in the air at 1300 deg C was investigated. Diffusion saturation was conducted in Na-Si-Ti environment at 1000, 1100 and 1200 deg C. Two oxidation stages were established. Initially the surface layer composed of higher silicides is oxidized with formation of SiO2, Nb2O5, TiO2 oxides and the lower Vb5Si3 silicide. After that the inner layer composed of lower silicides interacts with oxygen with Nb2O5 formation. It is shown that Si-Ti coatings produced at 1200 deg C possess the highest heat resistance

  10. Corrosion performance of heat resistant alloys in Na2SO4-V2O5 molten salts

    The corrosion resistant of three heat resistant alloys in molten vanadium pentoxide (V2O5), sodium sulfate (Na2SO4) and 80(mol%) V2O5-20Na2SO4 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 V2O5 and the 80V2O5-20Na2SO4 mixture, and 800, 900 and 1000 deg. C for Na2SO4. 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 Cr2O3, Al2O3 and SiO2 layers, by the salts and internal sulfidation

  11. 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.)

  12. 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

  13. Enhanced Heat Resistance of Al-Cu-Mg Alloy by a Combination of Pre-stretching and Underaging

    Wang, Xiaohu; Liu, Zhiyi; Bai, Song; Lin, Lianghua; Ye, Chengwu; Wang, Heng

    2016-06-01

    Enhanced heat resistance of Al-Cu-Mg alloy by employing a combined effect of pre-stretching and underaging has been characterized by thermal exposure, tensile testing, transmission electron microscopy (TEM) examination, and quantitative analysis. Tensile testing results showed that the samples subjected to both pre-stretching and underaging processing, presented a high tensile strength up to 440 MPa after thermal exposure at 200 °C for 500 h. This suggests that the long-time application temperature of Al-Cu-Mg alloys, which were normally applied at elevated temperature below 150 °C or even below 100 °C, can be raised to 200 °C by employing a combined effect of pre-stretching and underaging. TEM results showed that a fine and a narrow size distribution range of S' phase was formed by the combined processing of pre-stretching and underaging, as compared to that without pre-stretching. Quantitative analysis results indicated that this narrow range of size distribution greatly reduced the growth rate of S' phase during thermal exposure. It is suggested that this effect was ascribed to the Ostwald ripening mechanism.

  14. Peculiarities of structure transformations of heat resistant nickel alloy during high temperature heating

    By means of direct experiments (using microroentgenospectral analysis, electron microscopy, high-temperature metallography) it is shown that large formations of the exceeding phase in complexly alloyed nickel alloys present eutectic colonies (γ'+γ). Carbide of the N3W3C type is crystallized from the liquid in interaxial spaces close to the eutectics (γ'+γ) as a result of the substitution of the elements forming γ'-phase: Ti, Nb and Hf for tungsten. Using the method of electric resistance temperature range of dissolving of highly disperse γ'-phase of the given alloy in the Ni-Cr-Co-W-Al-Ti-Nb-Hf system is established. A polythermal cross section of a part of pseudodouble diagram (γ-γ') of the alloy studied is plotted on the basis of microroentgenospectral, phase and resistometric analyses. It is shown that solubility curve on the diagram has a point of bending near solidus temperature. At that, the temperature of complete dissolving of the disperse γ'-phase in γ-solid solution is 30 deg lower than Tsub(s)

  15. 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.)

  16. 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.

  17. Erosion resistance in a stationary arc of powder materials on the base of heat resisting alloys

    Minakova, R.V.; Kostenetskaya, L.I.; Krusanova, A.P.; Kukhtikov, V.A.; Smirnov, A.V.; Lugovskaya, E.S. (AN Ukrainskoj SSR, Kiev. Inst. Problem Materialovedeniya)

    1983-08-01

    Comparison investigations of some properties of the Mo-Cu, Mo-Ni(Co)-Cu materials and the W-Cu, W-Ni-Cu compositions used at the present time as well as contact pairs prepared from them is conducted. It is shown that electroerosion wear of the contacts is connected not only with the material properties but also with features of structural changes in the working layer under effect of arc discharge. It is shown also that directed alloying with respect to the origin of phase transition in the electrode material and the medium effect during current commutation promotes electroerosion resistance.

  18. Evaluation on materials performance of Hastelloy Alloy XR for HTTR uses-6. Tensile and creep properties of heat exchanger tube base materials and its welded-joints

    Tensile and creep properties of heat exchanger tube base materials and its welded-joints were investigated as a series of evaluation tests on Hastelloy Alloy XR heat exchanger tube and filler metal for the High Temperature Engineering Test Reactor (HTTR) components. As for tensile properties after thermal aging of base materials and welded joints, ductility was remarkably reduced at room temperature while it was raised at 950degC. On creep properties, the difference between base materials and welded joints in creep rupture strength was relatively small. Creep rupture elongation tended to decrease with increasing rupture time, and rupture elongation of welded joint had a tendency to be lower than that of base material. On the other hand, a comparison of plate with tube on high temperature tensile ductility after thermal aging was found to be higher in tube than in plate while its difference was slight at room temperature. As for creep properties, base materials and welded joints of tube had a tendency to be slightly shorter in rupture time at lower stress and long terms than those of plate. However, it is concluded that this is not problematic in practical uses from the fact that the rupture time in tube is comparable or greater than that of Hastelloy Alloy XR master curve and that it is much longer than that of design creep rupture strength =SR=. (author)

  19. 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

  20. 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

  1. 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.

  2. 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...

  3. 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.

  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. Investigation into effect of tin and zirconium alloying on high-temperature strength and heat resistance of Ti3Al compound base alloy

    A study is made of the effect of tin and zirconium on the phase composition, high-temperature strength and heat resistance of a Ti3Al compound. The study has been made over the (Ti3Al + 3% Zr)-Sn section, the concentration of tin being varied from 0 to 20 wt%. The high-temperature strength of the materials investigated has been studied by the centrifugal bending method and long-term strength at 700 - 800 deg C. The heat resistance has been evaluated by the results of gravimetric studies of sample oxidation in air at 600, 800 and 1000 deg C. The data of differential thermal and microstructural analyses are used to construct the phase diagram of the (Ti3Al + 3% Zr)-Sn partial section. Doping the Ti3Al intermetallide with tin and zirconium is shown to enhance considerably its high-temperature strength within the entire temperature range under study (from room temperature to 800 deg C) and its heat resistance at 600 deg C. The introduction of tin and zirconium is detrimental to the heat resistance of Ti3Al at 800 deg C and especially at 1000 deg C

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

    Brinkman, C. R.; Rittenhouse, P. L.; Corwin, W.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...... 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....

  7. 高硅合金耐热铸铁生产球墨铸铁模具的研制%Research on producing ductile iron mould with high silicon alloy heat resistant cast iron

    梁冰利; 王宏亮; 韩黎

    2012-01-01

    对铸铁模具使用工况进行了分析,采用了高硅合金耐热铸铁为生产球墨铸铁模具的材质,并介绍了高硅合金耐热球墨铸铁模具的消失模铸造工艺、冶炼工艺、热处理工艺以及该材质模具的实际使用效果.实际生产表明:高硅合金耐热球墨铸铁具有优越的综合耐热疲劳性能,大大提高了模具寿命.%The actual operating conditions of cast iron mould were analyzed. The silicon alloy heat resistant cast iron was adopted to produce ductile iron mould, and the lost foam casting process, smelting process, heat treatment process of the high silicon alloy heat resistant ductile iron mould as well as the actual use effect of the mould with this material were introduced. The practical production shows that the high silicon alloy heat resistant cast iron has superior heat-resistant and fatigue properties, which improves the mould life.

  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. Fixed time integration-emission spectrochemical analysis of nickel-base alloys and heat resisting steels for minor amount of elements

    The emission spectrochemical analysis of nickel-base alloys and heat resisting steels by the fixed time integration method has been developed. Nickel contents of 9 to 76% in the samples were examined in this study. For such samples, the internal standard method was inadequate, while the fixed time integration method gave good accuracy in the determination of minor elements in these samples. Elements analysed were C, P, S, B, Si, Ta, Co, Fe, Mn, Nb, Cu, Ti, Zr and Al. At first, ternary alloys containing a constant amount of cobalt (0.5, 1.0, 3.0, 6.0, 10.0, or 20.0%) with changing amounts of nickel and iron were prepared in order to examine the effect of nickel and iron content on the determination of these elements. It was found that the samples should be classified to two groups according to the nickel content, that is one group corresponding to 9 - 60% nickel and the other to 60 - 76%, and calibration curves had to be made separately. The equations of calibration curves were given in the regression lines of the first order in the determination of minor elements. For correcting the effect of neighbouring lines, coefficients of correction were derived by the multiple regression analysis. The relation between the sensitivity of analysis and the coefficient of correction was examined. As the sensitivity, the gradient of calibration curves was chosen, and it was observed that there was a linear correlation between the gradient and the partial regression coefficient. After all, the relation of hyperbola was concluded to exist between the gradient and the coefficient of correction in the determination of most elements. The gradients of calibration curves in the two groups were almost the same, but the gradients of the group containing more amount of nickel were a little larger than those of the other. (author)

  10. 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)

  11. Production of diffusion heat-resistant coatings on niobium

    A possibility of producing diffusion heat-resistant coatings on the 5VMTs niobium alloy has been investigated. Coating heat-resistance was investigated in the air at 800-1100 deg C. Given are brief characteristics of diffusion coatings produced. It is shown, that the Re and V coatings have satisfactory protective properties

  12. 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.)

  13. Effects of oxidation on the impact energy of Hastelloy S and Hastelloy C-4 Charpy V-notch specimens heated in air at 6000 to 8000C

    The 90SrF2 heat source being developed at PNL utilizes a Hastelloy S or Hastelloy C-4 outer capsule having a 0.5-in.-thick wall to contain the Hastelloy C-276 inner capsule. The primary objective of the study was to demonstrate that the air oxidation of the outer capsule that could occur during heat-source service would not degrade the ductility and Charpy impact strength of the capsule below the licensing requirements given in Section 1.1. The 90SrF2 heat source under development is intended for general-purpose use. Compatibility considerations limit the interface temperature between the 90SrF2 and Hastelloy C-276 inner capsule to a maximum of 8000C. The outer capsule surface temperature will be somewhat less than 8000C, and depending on the service, may be substantially lower. The oxidation tests were therefore carried out at 6000 to 8000C for exposures up to 10,000h to cover the range of temperature the outer capsule might expect to encounter in service. The results showed that the oxidation of Hastelloy S and Hastelloy C-4 in air at 6000 to 8000C is very slow, and both alloys form adherent oxide layers that serve to protect the underlying metal. Subsurface attack of Hastelloy S and Hastelloy C-4 due to oxidation was greater than expected, considering the slow oxidation rates of the two alloys at 6000 to 8000C. Estimates of subsurface attack, determined from micrographs of the oxidized specimens, showed erratic results and it was impossible to assign any type of rate equation to the subsurface attack. A conservative estimate of long-term effects can be made using a linear extrapolation of the test results. There were no significant differences between the room-temperature Charpy impact energy of Hastelloy S and Hastelloy C-4 specimens oxidized in air at 6000 to 8000C and control specimens heated in vacuum

  14. 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.)

  15. The suitability of selected austenitic stainless steels and Hastelloy C276 alloys as substrates for thin film deposition using spray pyrolysis

    Al Khateeb, Shadi [Al-Balqa' Applied Univ., Al-Salt, Jordan (Jordan). Materials Engineering Dept.

    2013-03-15

    To detect the suitability of the American Iron and Steel Institute grade 304, 309, 310, 316L steels and Hastelloy C276 substrates for thin film deposition using spray pyrolysis, the substrates were pre-heated between 400-700 C and soaked for one hour. American Society for Testing and Materials standards A262-A, E and G28-A were then applied. The substrates of 304 heated at 400, 600-700 C, the 310 heated between 450-700 C and the as-received 310 were not found suitable. However it was found that the 304, 309, and 310 substrates were suitable up to 550 C, the 316L up to 700 C and the C276 up to 550 C. (orig.)

  16. 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

  17. 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.

  18. Microstructure and Corrosion Resistance of CrN and CrN/TiN Coated Heat-Resistant Steels in Molten Aluminum Alloy

    LinCS; PengH

    2001-01-01

    The components of the equipment for processing the Al melts into the molded parts can be markedly corroded by the molten Al. In this study, a 4 μm CrN coating or CrN/TiN multilayer coating for providing the physical and chemical barriers between the molten reactive Al and the steel substrate were deposited by Cathodic Arc Evaporation onto 10 mm-thick heat-resistant steel plates. The dipping tests were conducted in a 700℃ A356 melt for 1 to 21 h at intervals of 3 h. The damage of the coated steel was eva...

  19. 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

  20. 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

  1. Kinetics of evaporation from the surface of refractory nickel and titanium alloys with heat resistant coatings during their irradiation by high-power pulsed ion beams

    The effect of the irradiating conditions by high-power pulsed ion beams (HPPIB) on the ablation rate was studied. The conditions of irradiation (ions of carbon and protons, ion energy E=300-600 keV, the ion current density in a pulse j=60-500 A·cm-2, pulse duration τ=50-100 ns) were realized in 'Temp' and 'Vera' accelerators. The study of the evaporation kinetics was carried out using targets manufactured from GS26NK nickel super-alloy with NiCrAlY coating and from Vt9 and VT18U titanium alloys with Zr N and TiSiB coatings. It is shown that values of the ablation rate achieve 0.04 μm (TiSiB), 0.4 μm (NiCrAlY), and 1 μm (Zr N) during a pulse under the optimal conditions of HPPIB irradiation

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. Oxidation of Hastelloy C276

    Park, J.-H.; Chen, L.; Goretta, K. C.; Koritala, R. E.; Balachandran, U.

    2002-05-01

    Oxidation of Hastelloy C276 was studied at 300-800 °C in atmospheres that ranged from 0.01 to 100% O2. X-ray diffraction and scanning electron microscopy indicated formation of Cr2O3 scales. The oxidation kinetics were approximately parabolic, but, contrary to expectations, there was no clear trend of scale-growth kinetics vs. oxygen partial pressure. This anomalous response was attributed to an extrinsic effect from cation doping of the scale, with a possible contribution from the rough, as-rolled surface finish of most of the coupons that were tested. The scales that formed on polished surfaces at 500 °C were smooth and nanocrystalline; those that formed at 800 °C were dense and consisted of faceted grains with an average size of ≈0.5-1 μm.

  7. Oxidation of Hastelloy C276

    Oxidation of Hastelloy C276 was studied at 300-800 deg. C in atmospheres that ranged from 0.01 to 100% O2. X-ray diffraction and scanning electron microscopy indicated formation of Cr2O3 scales. The oxidation kinetics were approximately parabolic, but, contrary to expectations, there was no clear trend of scale-growth kinetics vs. oxygen partial pressure. This anomalous response was attributed to an extrinsic effect from cation doping of the scale, with a possible contribution from the rough, as-rolled surface finish of most of the coupons that were tested. The scales that formed on polished surfaces at 500 deg. C were smooth and nanocrystalline; those that formed at 800 deg. C were dense and consisted of faceted grains with an average size of ≅0.5-1 μm

  8. 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

  9. Phase precipitation and time-temperature-transformation diagram of Hastelloy

    Transmission electron microscopy (TEM) was employed to study the phase precipitation in Hastelloy X heat-treated at 750, 850, and 900 C for 26 and 100 h. Phase identification was made by electron micro-diffraction and energy dispersion spectroscopy (EDS) X-ray micro-chemical analysis. In addition to the fcc matrix, four different precipitation phases were observed: M6C, M23C6, σ, and μ. The current observations were combined with literature results to build a time-temperature-transformation (TTT) diagram for this alloy. This TTT diagram depicted time-temperature regimes where various phases were formed; thus, it provided information about the general precipitation kinetics for the alloy. (orig.)

  10. 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

  11. Corrosion behavior of Hastelloy C-276 in supercritical water

    Zhang Qiang [National Key Laboratory for Nuclear Fuel and Materials, Nuclear Power Institute of China, P.O. Box 436, Chendu 610041 (China); Tang Rui [National Key Laboratory for Nuclear Fuel and Materials, Nuclear Power Institute of China, P.O. Box 436, Chendu 610041 (China)], E-mail: xajttr@163.com; Yin Kaiju; Luo Xin [National Key Laboratory for Nuclear Fuel and Materials, Nuclear Power Institute of China, P.O. Box 436, Chendu 610041 (China); Zhang Lefu [College of Nuclear Science and Technology, Shanghai Jiaotong University, Shanghai 200240 (China)

    2009-09-15

    The corrosion behavior of a nickel-based alloy Hastelloy C-276 exposed in supercritical water at 500-600 deg. C/25 MPa was investigated by means of gravimetry, scanning electron microscopy/energy dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. An oxide scale with dual-layer structure, mainly consisting of an outer NiO layer and an inner Cr{sub 2}O{sub 3}/NiCr{sub 2}O{sub 4}-mixed layer, developed on C-276 after 1000 h exposure. Higher temperature promoted oxidation, resulting in thicker oxide scale, larger weight gain and stronger tendency of oxide spallation. The oxide growth mechanism in SCW seems to be similar to that in high temperature water vapor, namely solid-state growth mechanism.

  12. 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.

  13. 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

  14. 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)

  15. Genetic determinants of heat resistance in Escherichia coli

    Ryan eMercer; Jinshui eZheng; Rigoberto eGarcia-Hernandez; Lifang eRuan; Michael eGänzle; Lynn eMcMullen

    2015-01-01

    Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 mi...

  16. 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.)

  17. Multiscale modeling and experiment validation of microstructure evolution induced by Ar+ irradiation in hastelloy C276

    The microstructure evolution induced by Ar+ irradiation (room temperature, about 10 dpa) in nickel based alloy Hastelloy C276 was studied using molecular dynamics and cluster dynamics, and a multiscale modeling code Radieff was constructed based on rate theory. The nucleation and growth of interstitial dislocation loops and void were studied by Radieff code. C276 was irradiated by 115 keV Ar+ at room temperature as validation experiment using transmission electron microscope (TEM)-implanter/accelerator interface facility at Wuhan University, and the microstructure evolution was observed by TEM. The size of dislocation loops simulated by Radieff is in good agreement with experiment. (authors)

  18. 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...

  19. 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)

  20. 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

  1. Effectiveness of diffusion coatings of noble metals for heat resistance improvement

    To establish the possibility of palladium coatings substitution for platinum ones a study was made on heat resistance of these coatings for 5VMTs niobium alloy at 1150 deg C. Coatings were applied at 950 deg C by diffusion method in lithium melt with addition of 3 mas% palladium or platinum. Heat resistance tests of samples with coatings were conducted in the air during 100 h. The efficiency of protective coatings was evaluated by gravimetric and metallographic methods. It was established that palladium coating thickness changes less intensively as compared to platinum one and is controlled by the process of formation of dense film of hard oxide preventing evaporation of metallic palladium. It was concluded that substitution of niobium alloy palladization for platinization is possible

  2. High temperature corrosion of cast heat resisting steels in CO + CO2 gas mixtures

    Xu, Nan; Monceau, Daniel; Young, David; Furtado, Jader

    2008-01-01

    Two commercial variants of the cast heat resistant grade HP40Nb (Fe–25Cr–35Ni, Nb modified) were exposed to CO/CO2 gases at 982 and 1080 C in order to simulate exposure to the carbon and oxygen potentials realised in steam reformers under normal and overheated conditions. Both alloys developed external chromium-rich oxide scales, intradendritic silica precipitates and interdendritic oxide protrusions where primary, interdendritic carbides were oxidised in situ. Surprisingly, the lower silicon...

  3. 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)

  4. Niobium effect on structure and heat resistance of Si-Ti-Mo gaseous deposited coatings

    To determine a critical niobium content in protective silicide coatings investigation into niobium effect on the structure, phase composition and heat resistance of scale-resistant alloys of silicon-rich corner of the Si-Ti-Mo system, powders of which are used for production of gaseous deposited protective coatings on niobium and its alloys is conducted. It is stated that Si-Ti-Mo alloying with up to 20 mass% niobium at quantity ratio Csub(Ti)/Csub(Mo)=1:3 and at presence of free silicon Ssub(free) >= 0% does not change phase composition of alloys and it does not practically affect their heat resistance. Niobium is dissolved complex silicide Tisub(0.4-0.95) Mosub(0.6-0.05)-Sisub(2). Rate of oxidation of the mentioned alloys slightly decreases at formation of molybdenum-rich (Ti, Mo)Si2 silicide in the initial structure. Increase of niobium content in Si-Ti-Mo-Nb alloys results in change of oxide film structure under high-temperature oxidation bringing about its active crystallization

  5. Genetic determinants of heat resistance in Escherichia coli

    Ryan eMercer

    2015-09-01

    Full Text Available Escherichia coli AW1.7 is a heat resistant food isolate and the occurrence of pathogenic strains with comparable heat resistance may pose a risk to food safety. To identify the genetic determinants of heat resistance, 29 strains of E. coli that differed in their of heat resistance were analyzed by comparative genomics. Strains were classified as highly heat resistant strains, exhibiting a D60-value of more than 6 min; moderately heat resistant strains, exhibiting a D60-value of more than 1 min; or as heat sensitive. A ~14 kb genomic island containing 16 predicted open reading frames encoding putative heat shock proteins and proteases was identified only in highly heat resistant strains. The genomic island was termed the locus of heat resistance (LHR. This putative operon is flanked by mobile elements and possesses >99% sequence identity to genomic islands contributing to heat resistance in Cronobacter sakazakii and Klebsiella pneumoniae. An additional 41 LHR sequences with >87% sequence identity were identified in 11 different species of β- and γ-proteobacteria. Cloning of the full length LHR conferred high heat resistance to the heat sensitive E. coli AW1.7ΔpHR1 and DH5α. The presence of the LHR correlates perfectly to heat resistance in several species of Enterobacteriaceae and occurs at a frequency of 2% of all E. coli genomes, including pathogenic strains. This study suggests the LHR has been laterally exchanged among the β- and γ-proteobacteria and is a reliable indicator of high heat resistance in E. coli.

  6. 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.

  7. Long-term behaviour of heat-resistant steels and high-temperature materials

    This book contains 10 lectures with the following subjects: On the effect of thermal pretreatment on the structure and creep behaviour of the alloy 800 H (V. Guttmann, J. Timm); Material properties of heat resistant ferritic and austenitic steels after cold forming (W. Bendick, H. Weber); Investigations for judging the working behaviour of components made of alloy 800 and alloy 617 under creep stress (H.J. Penkalla, F. Schubert); Creep behaviour of gas turbine materials in hot gas (K.H. Kloos et al.); Effect of small cold forming on the creep beahviour of gas turbine blades made of Nimonic 90 (K.H. Keienburg et al.); Investigations on creep fatigue alternating load strength of nickel alloys (G. Raule); Change of structure, creep fatigue behaviour and life of X20 Cr Mo V 12 1 (by G. Eggeler et al.); Investigations on thermal fatigue behaviour (K.H. Mayer et al.); Creep behaviour of similar welds of the steels 13 Cr Mo 4 4, 14 MoV 6 3, 10 Cr Mo 910 and GS-17 Cr Mo V 5 11 (K. Niel et al.); Determining the creep crack behaviour of heat resistant steels with samples of different geometry (K. Maile, R. Tscheuschner). (orig.,/MM)

  8. 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.

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

    Gordon, Andrew J.; Walton, Kyle L. [Particulate Systems Research Center, Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Ghosh, Tushar K., E-mail: ghoshT@missouri.edu [Particulate Systems Research Center, Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States); Loyalka, Sudarshan K.; Viswanath, Dabir S.; Tompson, Robert V. [Particulate Systems Research Center, Nuclear Science and Engineering Institute, University of Missouri, Columbia, MO 65211 (United States)

    2012-07-15

    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.

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

    Gordon, Andrew J.; Walton, Kyle L.; Ghosh, Tushar K.; Loyalka, Sudarshan K.; Viswanath, Dabir S.; Tompson, Robert V.

    2012-07-01

    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.

  11. 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

    2015-01-01

    C-276 nickel-based alloy is a difficult-to-cut material. In high-speed machining of Hastelloy C-276, notching is a prominent fallure 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 0.59mm. 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.

  12. 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.

  13. Effect of strain rate on high-temperature low-cycle fatigue behavior of hastelloy X and hastelloy XR

    A series of strain controlled low-cycle fatigue tests at 900 deg C in the simulated HTGR helium environment were conducted on Hastelloy X and its modified version, Hastelloy XR, and the effect of strain rate on high-temperature low-cycle fatigue behavior was investigated. The results of this study provide the following conclusions; (1) Decreasing the strain rate led to notable reductions in the fatigue life. (2) Trends of strain softening and cyclic softening were observed at lower strain rates of 1 x 10-4 s-1 and 2 x 10-5 s-1. (3) Both fracture modes of the transgranular and the intergranular were recognized on the fracture surfaces, with the former mode being predominant at a comparatively high strain rate of 1 x 10-3 s-1. The intergranular fracture mode, however, became predominant at lower strain rates, 1 x 10-4 s-1 and 2 x 10-5 s-1. (4) The cumulative damage rule predicted an excessively coservative value for creep damage. (5) The data obtained lay on the straight line plots when the frequency modified fatigue life method was applied. No significant difference in fatigue behavior was resolved between Hastelloy X and Hastelloy XR under the test conditions employed. (author)

  14. Heat Resistance and Population Stability of Lyophilized Bacillus subtilis Spores

    Odlaug, Theron E.; Caputo, Ross A.; Graham, Gary S.

    1981-01-01

    Bacillus subtilis 5230 spores were lyophilized in 0.067 M phosphate buffer and stored at 2 to 8°C for 9 to 27 months. The lyophilized spores were reconstituted with buffer or 0.9% saline, and the heat resistance was determined in a thermoresistometer. Lyophilization had no effect on the heat resistance of the spores but did result in a slight decrease in population (≤0.3-logarithm reduction). The lyophilized spores maintained heat resistance and population levels over the test periods. The D-...

  15. 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)

  16. HEAT-RESISTANT COMPOSITES CURED BY ELECTRON BEAM

    Jian-wen Bao; Yang Li; Xiang-bao Chen; Feng-mei Li

    2001-01-01

    Electron beam (EB) curing of composites has many advantages. Heat-resistant EB-curing composites could substitute polyimide composites used in aeronautical engines. In this paper, 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 analysis (DMA). The experimental results show that the mechanical properties of the composites cured by EB could meet the specifications of aeronautical engines at 250°C.

  17. Mechanisms underlying extreme heat resistance of ascospores of Neosartorya fischeri

    Wyatt, T.T.

    2014-01-01

    Food spoilage causes immense losses of food products worldwide and negatively affects human health due the production of toxic compounds, so-called mycotoxins. Worldwide economic costs related to fungal spoilage amounts billions of euro each year. Mild heat treatments are used to minimize fungal spoilage. As an example, pasteurized food products, especially canned fruit and fruit juices, are still prone to spoilage by fungi that produce extreme heat-resistant ascospores. Heat-resistant ascosp...

  18. Creep properties of Hastelloy X in a carburizing helium environment

    In this work, we investigate the environmental effect on the creep behavior of Hastelloy X at 9000C in helium and air. Since helium coolant in HTGR is expected to be carburizing and very weakly oxidizing for most metals, testings were focused on the effect of carburizing and slight oxidation. Carburization decreases secondary creep strain rate and delays tertiary creep initiation. On the other hand, the crack growth rate on the specimen surface is enhanced due to very weak oxidation in helium, therefore the tertiary creep strain rate becomes larger than that in air. The rupture time of Hastelloy X was shorter in helium when compared with in air. Stress versus rupture time curves for both environments do not deviate with each other during up to 5000 hours test, and a ratio of rupture stress in helium to that in air was about 0.9

  19. Electrochemistry Corrosion Properties of Pulsed Laser Welding Hastelloy C-276

    Ma, G.; Niu, F.; Wu, D.; Qu, Y.

    Based on the welding quality requirement of Hastelloy C276 in the extreme environment, the electrochemistry corrosion property of laser welding Hastelloy C276 was evaluated in the neutral, acid and alkaline solutions, and the corroded surface was observed by the co-focal laser scanning microscope to confirm the corrosion mechanism. The results indicated, the corrosion trend of the weld was weaker than that of base metal in the neutral and acid solutions, but in the alkaline solutions, the corrosion trend of the base metal was weaker. However, the corrosion rate of the weld was much slower than that of base metal in all solutions. At the point of corrosion mechanism, in the acid and alkaline solutions, the base metal and weld showed the uniform corrosion. However, in the neutral solution, the selective corrosion and intergranular corrosion occurred in the base metal and the weld, respectively.

  20. 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...

  1. Thermal response of heat-resistant layer with pyrolysis

    Huang Haiming

    2012-01-01

    Full Text Available A model is developed for analyzing the thermal response of the heat-resistant layer composed of high silica fiber reinforced phenolic matrix composites(SiO2/P and aluminum, in which pyrolysis and phase transitions are exsited, such as melt, vaporization and sublimation. Based on this model, the thermal response of the heat-resistant layer with different SiO2/P thickness is calculated under a heat flux by using FORTRAN codes. As indicated in the results, the slope of temperature gets a sudden decline at the pyrolysis interface, which is due to the latent heat of pyrolysis; the thickness of heat-resistant layer has little influence on the heating-surface temperature, however, the back temperature may increase with the decreasing thickness; and the thermal conductivity of carbonized layer is very important to thermal response.

  2. Thermal response of heat-resistant layer with pyrolysis

    Huang Haiming; Xiaoliang Xu; Huang Guo; Zhang Zimao

    2012-01-01

    A model is developed for analyzing the thermal response of the heat-resistant layer composed of high silica fiber reinforced phenolic matrix composites(SiO2/P) and aluminum, in which pyrolysis and phase transitions are exsited, such as melt, vaporization and sublimation. Based on this model, the thermal response of the heat-resistant layer with different SiO2/P thickness is calculated under a heat flux by using FORTRAN codes. As indicated in the results, the slope of temperature gets a ...

  3. Fatigue crack propagation in Hastelloy X weld metal

    The fatigue crack growth rate of Hastelloy X weld metal increased with stress intensity, temperature, and inverse frequency. The results were correlated with the equation da/dN = (ΔK)/sup n/, for constant frequency or constant temperature. The values of A and n were computed with a linear regression algorithm. With decreasing frequency at constant ΔK and constant temperature (5380C) fatigue crack growth rates approach an upper limit. Fatigue crack growth rate of the weld metal was lower than that reported for base metal at 5380C and lower at 6490C for a frequency of 1 Hz

  4. 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

  5. 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.)

  6. High temperature protective silicide coatings for titanium-niobium alloys

    The accomplished investigation of heat resistance of silicide coatings on titanium - (30-50)% niobium alloys has revealed that the coatings ensure reliable corrosion protection up to 1100 deg due to formation of heat resistant disilicides and a silicon dioxide layer on alloy surface. Silicide coatings possess particular ductility

  7. 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.

  8. 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.

  9. 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...

  10. 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.)

  11. The synthesis of thermite heat and heat-resistant steels

    Жигуц, Юрій Юрійович

    2013-01-01

    The present paper the basic solutions to the problem of obtaining heat-resistant steels examined the use of thermite steels, the benefits of combining thermite steels with metallotermic methods of getting is showed. The advantages of metallotermic synthesis methods include: autonomy of processes, independence of energy sources, simplicity of equipment, high-performance process and easy transition from experimental research to industrial production. The need to developed the technology of synt...

  12. Development of heat resistant ion exchange resin. First Report

    In nuclear power stations, as a means of maintaining the soundness of nuclear reactors, the cleaning of reactor cooling water has been carried out. But as for the ion exchange resin which is used as the cleaning agent in the filtrating and desalting facility in reactor water cleaning system, since the heat resistance is low, high temperature reactor water is cooled once and cleaned, therefore large heat loss occurs. If the cleaning can be done at higher temperature, the reduction of heat loss and compact cleaning facilities become possible. In this study, a new ion exchange resin having superior heat resistance has been developed, and the results of the test of evaluating the performance of the developed ion exchange resin are reported. The heat loss in reactor water cleaning system, the heat deterioration of conventional ion exchange resin, and the development of the anion exchange resin of alkyl spacer type are described. The outline of the performance evaluation test, the experimental method, and the results of the heat resistance, ion exchange characteristics and so on of C4 resin are reported. The with standable temperature of the developed anion exchange resin was estimated as 80 - 90degC. The ion exchange performance at 95degC of this resin did not change from that at low temperature in chloride ions and silica, and was equivalent to that of existing anion exchange resin. (K.I.)

  13. 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

  14. 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)

  15. Design of martensitic/ferritic heat-resistant steels for application at 650 deg. C with supporting thermodynamic modelling

    Knezevic, V.; Balun, J. [Max-Planck-Institut fuer Eisenforschung GmbH, 40074 Duesseldorf (Germany); Sauthoff, G. [Max-Planck-Institut fuer Eisenforschung GmbH, 40074 Duesseldorf (Germany)], E-mail: g.sauthoff@mpie.de; Inden, G.; Schneider, A. [Max-Planck-Institut fuer Eisenforschung GmbH, 40074 Duesseldorf (Germany)

    2008-03-25

    In view of developing novel heat-resisting steels for applications in conventional power plants with service temperatures of 650 deg. C, a series of martensitic/ferritic model steels with 12 wt.%Cr were studied to achieve an increased creep resistance through additional alloying with various elements for controlled precipitation of M{sub 23}C{sub 6} carbides, MX carbonitrides and intermetallic Laves phase. The alloy design relied on thermodynamic simulation calculations using Thermo-Calc and DICTRA. The mechanical testing concentrated on creep at 650 deg. C for up to 8000 h. The alloy optimization resulted in creep rupture strengths above those of the martensitic/ferritic P92 steel. The work was part of a cooperative project within the German MARCKO program.

  16. Design of martensitic/ferritic heat-resistant steels for application at 650 deg. C with supporting thermodynamic modelling

    In view of developing novel heat-resisting steels for applications in conventional power plants with service temperatures of 650 deg. C, a series of martensitic/ferritic model steels with 12 wt.%Cr were studied to achieve an increased creep resistance through additional alloying with various elements for controlled precipitation of M23C6 carbides, MX carbonitrides and intermetallic Laves phase. The alloy design relied on thermodynamic simulation calculations using Thermo-Calc and DICTRA. The mechanical testing concentrated on creep at 650 deg. C for up to 8000 h. The alloy optimization resulted in creep rupture strengths above those of the martensitic/ferritic P92 steel. The work was part of a cooperative project within the German MARCKO program

  17. 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

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

    Takahide Fukuyama

    2011-09-01

    Full Text Available 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.

  19. 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.

  20. 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)

  1. Heat Resistance of TiN Coated HSS Tools

    周兰英; 周焕雷; 贾庆莲

    2003-01-01

    The cutting friction, cutting deformation, producing heat, conducting heat, temperature field of TiN coated HSS tools in the cutting process are discussed profoundly. In order to make clear the heat property of TiN coated tools, from the micromechanism angle, the relationship of the heat property and the crystal structure of TiN compound is analyzed, and the regularity of TiN compound crystal structure changing with temperature rising is sought. The difference of the wear resistance and heat resistance of TiN coated tools deposited by c1 and c2 depositing techniques is proved by tests. The conclusions will offer the theoretical basis for correct design of geometrical parameters of TiN coated tools, rational selection of cutting regimes and optimization of the depositing technique.

  2. Applying Tep Measurements to Assess the Response of Hastelloy to Long Time Aging

    Ifergane, S.; Gelbstein, Y.; Dahan, I.; Pinkas, M.; Landau, A.

    2009-03-01

    Hastelloy C-276 service temperature is restricted due to precipitation of the intermetallic compound μ. Time-temperature curves indicate that the highest precipitation rate is obtained at about 870° C. Thermoelectric Power (TEP) measurements were applied to monitor the precipitation kinetics during aging at 870° C. The TEP was found to be well correlated with the amount of μ phase formed during aging and with the reduction in impact energy and ductility. It was demonstrated that TEP measurements could be used to monitor aging of Hastelloy C-276.

  3. Effect of Aluminium and Silicon on High Temperature Oxidation Resistance of Fe-Cr-Ni Heat Resistant Steel

    WANG Haitao; ZHAO Qi; YU Huashun; ZHANG Zhenya; CUI Hongwei; MIN Guanghui

    2009-01-01

    Fe-Cr-Ni heat resistant steels with different contents of Al and Si were cast in intermediate frequency induction furnace with non-oxidation method. With oxidation weight gain method, the oxidation resistance of test alloys was examined at 1 200℃ for 500 h. The effects of Al and Si on oxidation resistance were studied through analyses of X-ray diffraction (XRD) and scanning electron microscope (SEM). It is shown that the composition of oxide scales is a decisive factor for the oxidation resistance of heat resistant steels. The compounded scale composed of Cr2O3, ar-Al2O3, SiO2 and Fe(Ni)Cr2O4, with flat and compact structure, fine and even grains, exhibits complete oxidation resistance at 1 200℃ Its oxidation weight gain rate is only 0.081 g/(m2·h). By the criterion of standard Gibbs formation free energy, a model of nucleation and growth of the compounded scale was established. The formation of the compounded scale was the result of the competition of being oxidated and reduction among Al, Si, and the matrix metal elements of Fe, Cr and Ni. The protection of the compounded scale was analyzed from the perspectives of electrical conductivity and strength properties.

  4. 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.

  5. 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)

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Modification Approach of Fuzzy Logic Model for Predicting of Cutting Force When Machining Nickel Based Hastelloy C-276

    BASIM A. KHIDHIR; Bashir Mohamed; Mahmoud A.A. Younis

    2010-01-01

    Problem statement: Most Nickel based Hastelloy C-276 is a difficult-to-machine material because of its low thermal diffusive property and high strength at high temperature. Machinability consideration of nickel based Hastelloy C-276 in turning operations has been carried out using ceramic inserts under dry conditions. Approach: This study described a modification approach applied to a fuzzy logic based model for predicting cutting force where the machining parameters for c...

  11. Principles of alloying of Ni superalloys resistant to high-temperature corrosion

    The effect of alloying elements (Cr, Ti, Al, Co, W, Nb) on resistance against high-temperature corrosion of the nickel alloys, applied in the gas turbine building, is studied. The diagram of the alloys heat resistance level dependence on the alloying elements concentration is plotted, wherein three areas are separated: 1) the area of improved heat resistance due to the solid solution and dispersion strengthening; 2) the area of decreasing heat resistance due to formation of the carbide net by the grain boundaries; 3) the area of catastrophic decrease in the heat resistance by separation of the embrittlement topologically close-packed phases. The class of the high-temperature corrosion-resistant nickel alloys with different chromium content (13-30%), the Ti/Al > 1 concentration ratio and balanced content of high-melting and rare earth elements is created

  12. 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.

  13. 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.

  14. 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)

  15. Microstructural Features and Properties of High-hardness and Heat-resistant Dispersion Strengthened Copper by Reaction Milling

    YAN Peng; LIN Chenguang; CUI Shun; LU Yanjie; ZHOU Zenglin; LI Zengde

    2011-01-01

    The oxide dispersion strengthened copper alloys are attractive due to their excellent combination of thermal and electrical conductivities,high-temperature strength and microstructure stability.To date,the state-of-art to fabrication of them was the intemal oxidation (IO) process.In this paper,alumina dispersion strengthened copper (ADSC) powders of nominal composition of Cu-2.5 vo1%Al2O3 were produced by reaction milling (RM) process which was an in-situ gas-solid reaction process.The bulk ADSC alloys for electrical and mechanical properties investigation were obtained by sintering and thereafter hot extrusion.After the hot consolidation processes,the fully densified powder compacts can be obtained.The single y-Al2O3 phase and profile broaden effects are evident in accordance with the results of X-ray diffraction (XRD); the HRB hardness of the ADSC can be as high as 95; the outcomes should be attributed to the pinning effect ofnano γ-Al2O3 on dislocations and grain boundaries in the copper matrix.The electrical conductivity of the ADSC alloy is 55%IACS (International Annealing Copper Standard).The room temperature hardness of the hot consolidated material was approximately maintained after annealing for l h at 900 ℃ in hydrogen atmosphere.In terms of the above merits,the RM process to fabricating ADSC alloys is a promising method to improve heat resistance,hardness,electrical conductivity and wear resistance properties etc.

  16. Heat-resistant protein expression during germination of maize seeds under water stress.

    Abreu, V M; Silva Neta, I C; Von Pinho, E V R; Naves, G M F; Guimarães, R M; Santos, H O; Von Pinho, R G

    2016-01-01

    Low water availability is one of the factors that limit agricultural crop development, and hence the development of genotypes with increased water stress tolerance is a challenge in plant breeding programs. Heat-resistant proteins have been widely studied, and are reported to participate in various developmental processes and to accumulate in response to stress. This study aimed to evaluate heat-resistant protein expression under water stress conditions during the germination of maize seed inbreed lines differing in their water stress tolerance. Maize seed lines 91 and 64 were soaked in 0, -0.3, -0.6, and -0.9 MPa water potential for 0, 6, 12, 18, and 24 h. Line 91 is considered more water stress-tolerant than line 64. The analysis of heat-resistant protein expression was made by gel electrophoresis and spectrophotometry. In general, higher expression of heat-resistant proteins was observed in seeds from line 64 subjected to shorter soaking periods and lower water potentials. However, in the water stress-tolerant line 91, a higher expression was observed in seeds that were subjected to -0.3 and -0.6 MPa water potentials. In the absence of water stress, heat-resistant protein expression was reduced with increasing soaking period. Thus, there was a difference in heat-resistant protein expression among the seed lines differing in water stress tolerance. Increased heat-resistant protein expression was observed in seeds from line 91 when subjected to water stress conditions for longer soaking periods. PMID:27525950

  17. Corrosion of high nickel alloys in combined fluoride solutions for nuclear fuel reprocessing

    The chemical reprocessing of fuel from the Pressurized Water Reactor (PWR) Core 2, Seed 1 and 2, requires hydrofluoric acid, nitric acid, and sulfuric acid singly and in mixtures. High nickel alloys tested in scoping tests at the boiling point in PWR process solutions included Hastelloy C-276, Hastelloy C-4, Hastelloy S, Hastelloy G, Inconel 625, Inconel 690 and Incoloy 825. Evaluations of weld performance including some metallographic examinations are included. Different methods of welding and different heats of alloys were investigated. The effect of varying compositions and concentration of process solutions were examined in order to select conditions which would minimize corrosion. Corrosion results are also presented for two Hastelloy C276 corrosion test vessels fabricated from 3-inch welded pipe with welded nozzles. These vessels have been exposed to PWR process solution for several months. They have provided valuable information on the performance of welds, the attack at the vapor-liquid interface, and the mode of attack to be expected in process service. (U.S.)

  18. Production of heat-resistant metal-ceramic coatings on the basis of titanium silicide and nitride by thermoreactive electrospark surface strengthening

    Coatings on the basis of Ti5Si3 titanium silicide have been produced using the Thermoreactive Electrospark Surface Strengthening (TRESS) method. Their formation took place by applying a charge exothermic layer of specified composition (Ti-Si, Ti-Si3N4) onto a substrate and the subsequent chemical conversion in it that is maintained by energy of pulsed discharges. A series of investigations of structure, composition and properties (microhardness, thickness, integrity, and wear-resistance) of TRESS-coatings on OT4-1 titanium alloy was carried out. A dependence of depth of chemical conversion in charge layers on energy processing mode was found. It was established that the coatings produced during optimal processing mode (E = 0,3 J) facilitate an increase in microhardness, wear-resistance and heat-resistance of OT4-1 alloy

  19. 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

    2016-07-01

    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.

  20. 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.

  1. 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.)

  2. New progress in the theory and practice of heat-resisting concretes

    The main properties of heat-resistant cellular, light and heavy concretes based on high-alumina-, alumina- and Portland cements, liquid glass, alumo-phosphate binder and other binding materials containing different fine-ground additives and fillers are considered. The data of foreign and national investigations are presented concerning the effect of heating and mineral composition of cements and fine-ground mineral additions on the phase composition and structure of the cement stone and tensile properties of concretes. The foreign and national experience in the utilization of heat-resistant concretes when constructing thermal units in various branches of industry is described, as well as the economic effectiveness obtained herewith

  3. Structure optimization and damage behaviour of heat-resistant CrMoV-steels

    The object of the investigations was to optimize the heat treatment conditions of steel 12 CrMoV 4 3 (around 0,12% C; 1% Cr; 0,3% Mo; 0,25% V) on the basis of known structure-property relations of heat resistant steel-CrMoV in such way that the performance of this steel relating to its long-term heat resistance is completely utilized. Further, the influence of heat treatment or of the initial structure was analyzed as well as of further factors on the evolution of damages by formation of pores due to creep. (orig.)

  4. Study of heat resistance in the materials under high-speed heating

    The method and installation to determine heat resistance in materials at high heating rates (up to 106 K/s) according to the temperautre gradient between the surface and the core of the specimen which results in the destruction of the material tested are described. The temperature gradient occurs because of the skin effect when a high-frequency current pulse passes through the specimen. Using the method suggested investigation of molybdenum and tantalum heat resistance is carried out. It is shown that under conditions of pulse heating tantalum heat resistsance is higher

  5. Nd:YAG laser cladding of marine propeller with hastelloy C-22

    Kim, J.D.; Kang, K.H.; Kim, J.N. [Dept. of Mechanical Engineering, Inha University, Yonghyundong 253, Namku, 402-751, Incheon (Korea)

    2004-09-01

    Nd:YAG laser cladding with automatic wire feeding (Hastelloy C-22) has been done to increase the lifetime of marine propellers made of HBsC1. The effects of processing parameters on the quality of clad layer have been investigated and clad layers have analyzed by optical microscopy and Vickers hardness tester. The method to overcome the drop transfer problem during the wire feeding has been introduced. A cladding speed that is too fast or too slow influenced the shape of clad. The good clad layer without cracks and with low dilution has been obtained with the optimum processing parameters. (orig.)

  6. 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.

  7. 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)

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

    MJ Danielson; SG Pitman

    2000-02-23

    Both the 316L stainless steel and Hastelloy{reg_sign} 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.

  9. 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.)

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

    Wei YAN; Wei WANG; Yi-Yin SHAN; Ke YANG

    2013-01-01

    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 elabo- rated, including (1) martensitic lath widening, (2) disappearance of prior austenite grain boundary, (3) 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.

  11. Heat resistance of carbon steel with chromium-based gas-thermal sprayed coatings

    Heat resistance of steel with chromium-base plasma sprayed coating is studied in comparison with chromium coating and base material. The specimens were oxidized at the air under 1250 K during 48 h. Investigations into steel-chromium coating interface were carried out and the structure of cinder was studied. Refs. 7, figs. 2

  12. Quantifying variety-specific heat resistance and the potential for adaptation to climate change.

    Tack, Jesse; Barkley, Andrew; Rife, Trevor W; Poland, Jesse A; Nalley, Lawton Lanier

    2016-08-01

    The impact of climate change on crop yields has become widely measured; however, the linkages for winter wheat are less studied due to dramatic weather changes during the long growing season that are difficult to model. Recent research suggests significant reductions under warming. A potential adaptation strategy involves the development of heat resistant varieties by breeders, combined with alternative variety selection by producers. However, the impact of heat on specific wheat varieties remains relatively unstudied due to limited data and the complex genetic basis of heat tolerance. Here, we provide a novel econometric approach that combines field-trial data with a genetic cluster mapping to group wheat varieties and estimate a separate extreme heat impact (temperatures over 34 °C) across 24 clusters spanning 197 varieties. We find a wide range of heterogeneous heat resistance and a trade-off between average yield and resistance. Results suggest that recently released varieties are less heat resistant than older varieties, a pattern that also holds for on-farm varieties. Currently released - but not yet adopted - varieties do not offer improved resistance relative to varieties currently grown on farm. Our findings suggest that warming impacts could be significantly reduced through advances in wheat breeding and/or adoption decisions by producers. However, current adaptation-through-adoption potential is limited under a 1 °C warming scenario as increased heat resistance cannot be achieved without a reduction in average yields. PMID:26577840

  13. Clothing evaporative heat resistance - Proposal for improved representation in standards and models

    Havenith, G.; Holmér, I.; Hartog, E.A. den; Parsons, K.C.

    1999-01-01

    Clothing heat and vapour resistances are important inputs for standards and models dealing with thermal comfort, heat- and cold-stress. A vast database of static clothing heat resistance values is available, and this was recently expanded with correction equations to account for effects of movement

  14. 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.

  15. Simple bond-order-type interatomic potential for an intermixed Fe-Cr-C system of metallic and covalent bondings in heat-resistant ferritic steels

    It is known that M23C6(M = Cr/Fe) behavior in heat-resistant ferritic steels affects the strength of the material at high temperature. The ability to garner direct information regarding the atomic motion using classical molecular dynamics simulations is useful for investigating the M23C6 behavior in heat-resistant ferritic steels. For such classical molecular dynamics calculations, a suitable interatomic potential is needed. To satisfy this requirement, an empirical bond-order-type interatomic potential for Fe-Cr-C systems was developed because the three main elements to simulate the M23C6 behavior in heat-resistant ferritic steels are Fe, Cr, and C. The angular-dependent term, which applies only in non-metallic systems, was determined based on the similarity between a Finnis-Sinclair-type embedded-atom-method interatomic potential and a Tersoff-type bond-order potential. The potential parameters were determined such that the material properties of Fe-Cr-C systems were reproduced. These properties include the energy and lattice constants of 89 crystal structures; the elastic constants of four realistic precipitates; the bulk moduli of B1, B2, and B3 crystals; the surface energies of B1 and B2 crystals; and the defect-formation energies and atomic configurations of 66 Fe-Cr-C complexes. Most of these material properties were found to be reproduced by our proposed empirical bond-order potentials. The formation energies and lattice constants of randomly mixed Fe-Cr alloys calculated using the interatomic potentials were comparable to those obtained through experiments and first-principles calculations. Furthermore, the energies and structures of interfaces between Cr carbide and α-Fe as predicted through first-principles calculations were well reproduced using these interatomic potentials

  16. 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;

    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...

  17. The Kinetics of Metadynamic Recrystallization in a Ni-Cr-Mo-Based Superalloy Hastelloy C-276

    Zhang, Chi; Zhang, Liwen; Shen, Wenfei; Liu, Cuiru; Xia, Yingnan

    2016-02-01

    The metadynamic recrystallization (MDRX) behavior of a typical Ni-Cr-Mo-based superalloy Hastelloy C-276 was investigated using two-stage isothermal compression tests on a Gleeble thermal-mechanical simulator in the temperature range of 1050-1200 °C, the strain rate range of 0.1-5.0 s-1, the strains of 0.32, 0.45, and 0.6 at the first stage of compression, and the interval times of 0.5-30 s. The results show that the microstructure and the stress-strain relation of the studied superalloy vary during the interruption period due to the occurrence of MDRX. The MDRX softening fraction and recrystallized grain size increase rapidly with the increasing of interval time, deformation temperature, and strain rate. The effect of strain at the first stage of compression on MDRX is less pronounced. The kinetics of MDRX softening was established based on the flow stress curves, and the apparent activation energy of MDRX of Hastelloy C-276 is evaluated as 241 kJ/mol.

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

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

    2015-11-01

    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.

  19. Fabrication and characterization of superhydrophobic and superlipophilic silica nanofibers mats with excellent heat resistance

    Gao S.

    2016-01-01

    Full Text Available A kind of silica nanofibers (SNF mats with superhydrophobicity and superlipophilicity as well as excellent heat resistance, had been prepared by modifying of 1, 1, 1, 3, 3, 3-hexamethyldisilazane on electrospun SNF mats. The effects of heat treatment time on properties of modified SNF mats were investigated by scanning electron microscopy, nitrogen absorption analysis, X-ray photoelectron spectroscopy, and contact angle measurement. With high specific surface area 240.1 m2/g, the optimal modified SNF mat approached water contact angle (WCA 153.2° and fuel contact angle (FCA 0°, furthermore, even after annealing by 450°C in air for 1h , WCA remained at 135.5° and FCA kept at 3.8°, which opened a new way to improve heat resistance of fuel-water filter paper.

  20. Durability of welded joints of heat resistant steels with crack-similar defects

    Estimation of the effect of cracks and crack-similar defects on supporting power of welded joints is important for estimation of workability and substantiation of control periodicity of welded joints of responsible elements of power equipment operating under creep. High-temperature welded joints of heat resistant steels of Cr-Mo-V system are shown to be characterized by low sensitivity to stress concentration

  1. 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.

  2. 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.)

  3. 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...

  4. 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

  5. Corrosion aspects of compatible alloys in molten salt (FLiNaK) medium for Indian MSR program in the temperature range of 550-750 °C using electrochemical techniques

    Corrosion behaviours of different alloys were evaluated in fluoride eutectic FLiNaK in the temperature range of 550-750 °C under static and dynamic conditions. Electrochemical polarization and impedance techniques were used to estimate corrosion rate. The results showed that the corrosion process was controlled by activation and in some cases by formation of passive layer. In static mode, the corrosion rates followed the order : Inconel 625 > Inconel 617 > Inconel 600 > Incoloy 800 > Ni 220 > Hastelloy N > Incoloy 800HT. In dynamic mode, Hastelloy N and Incoloy 800HT showed better corrosion resistance in comparison to other alloys. (author)

  6. 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.

  7. Formation Mechanism of Type IV Failure in High Cr Ferritic Heat-Resistant Steel-Welded Joint

    Liu, Y.; Tsukamoto, S.; Shirane, T.; Abe, F.

    2013-10-01

    The mechanism of type IV failure has been investigated by using a conventional 9Cr ferritic heat-resistant steel Gr.92. In order to clarify the main cause of type IV failure, different heat treatments were performed on the base metal in order to change the prior austenite grain (PAG) size and precipitate distribution after applying the heat-affected zone (HAZ) simulated thermal cycle at the peak temperature of around A c3 ( A c3 HAZ thermal cycle) and postweld heat treatment (PWHT). The microstructural evolution during the A c3 HAZ thermal cycle and PWHT was investigated by means of scanning electron microscope (SEM), electron backscatter diffraction (EBSD), electron probe microanalysis (EPMA), and transmission electron microscope (TEM). It was found that M23C6 carbides were scarcely precipitated at the newly formed fine PAG, block, and lath boundaries in A c3 HAZ-simulated Gr.92, because the carbide forming elements such as Cr and C were segregated at the former PAG and block boundaries of the base metal. On the other hand, if all the boundaries were covered by sufficient M23C6 carbides by homogenization of the alloying elements prior to applying the HAZ thermal cycle, the creep strength was much improved even if the fine PAG was formed. From these results, it is concluded that fine-grained microstructure cannot account for the occurrence of type IV failure, and it only has a small effect during long-term creep. The most important factor is the precipitate formation behavior at various boundaries. Without sufficient boundary strengthening by precipitates, the microstructure of A c3 HAZ undergoes severe changes even during PWHT and causes premature failure during creep.

  8. Heat resistance of gametes of marine invertebrates in relation to temperature conditions under which the species exist

    Andronikov, V.B.

    1975-04-30

    The possible role of the heat resistance level of mature gametes and embryos of poikilotherms in the adaptation of a species to environmental temperature conditions was investigated. Within a species, heat resistance of gametes does not undergo any recognizable change even in the presence of significant fluctuations in temperature. Evidence in support of this statement was obtained on gametes of invertebrates belonging to different populations of the same species collected in different seasons, and on invertebrates maintained under different temperatures. The heat resistance of gametes is correlated with the degree of thermophily of the species concerned. Species living under similar temperature conditions exhibit minimal, if any, differences in heat resistance. Hence, the heat resistance level of their gametes is a function of temperature conditions of formation and existence of the species as a whole. During the ontogenesis of poikilotherms, eggs, zygotes and early stages of embryonic development are most susceptible to heat injury. The upper thermal limit for the normal development of eggs and embryos is only 1 to 3/sup 0/C higher than the temperatures encountered under natural conditions. It is concluded that the heat resistance level of gametes and embryos represents an adjustment to temperatures at which spawning, fertilization and earlier embryonal development occur. Temperatures which, throughout the year, exceed the upper thermal limit or remain below the lower thermal limit for the development of embryos, act as limiting factors for the species' distribution.

  9. 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

  10. VARIATION OF SUBSTRUCTURES OF PEARLITIC HEAT RESISTANT STEEL AFTER HIGH TEMPERATURE AGING

    R.C.Yang; K.Chen; H.X.Feng; H.Wang

    2004-01-01

    The observations of dislocations, substructures and other microstructural details were conducted mainly by means of transmission electron microscope (TEM) and scanning electron microscope (SEM) for 12Cr1Mo V pearlitic heat-resistant steel. It is shown that during the high temperature long-term aging, the disordered and jumbled phasetransformed dislocations caused by normalized cooling are recovered and rearranged into cell substructures, and then the dislocation density is reduced gradually. Finally a low density linear dislocation configuration and a stabler dislocation network are formed and ferritic grains grow considerably.

  11. Production of Heat Resistant Composite based on Siloxane Elastomer and Multiwall Carbon Nanotubes

    Bessonov, I. V.; Karelina, N. V.; Kopitsyna, M. N.; Morozov, A. S.; Reznik, S. V.; Skidchenko, V. Yu.

    2016-02-01

    Development of a new generation of composite with unique thermal properties is an important task in the fields of science and technology where material is operated at high temperatures and exposure to a short-wave radiation. Recent studies show that carbon nanomaterials (fullerenes and carbon nanotubes) could improve the thermal, radiation and thermal-oxidative stability of the polymer matrix. In this article the development of a new heat resistant composite based on elastomer and carbon nanotubes (CNT) was performed and physicochemical properties of final product were evaluated.

  12. 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

  13. Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties.

    Dulikravich, George S.; Sikka, Vinod K.; Muralidharan, G.

    2006-06-01

    The goal of this project was to adapt and use an advanced semi-stochastic algorithm for constrained multiobjective optimization and combine it with experimental testing and verification to determine optimum concentrations of alloying elements in heat-resistant and corrosion-resistant H-series stainless steel alloys that will simultaneously maximize a number of alloy's mechanical and corrosion properties.

  14. The microstructure and its impact on the high-temperature properties of the heat-resistant cast steel G-X 40 NiCr 35 25

    The report explains the influence of the elements Mo, W, Nb and Ti on the microstructure and thus on the high-temperature properties of the heat-resistant cast steel G-X 40 NiCr 35 25. The creep-rupture tests carried out at temperatures between 900deg C and 1100deg C for 2000 hours suggest that the interdendritic carbide skeleton as a non-creeping fiber reinforcement has a strong effect on the minimum creep rate. Especially the elements Nb and Ti have been found to reduce the minimum creep rate. Oxidation experiments have shown that the alloys with the lowest concentrations of the four elements varied in the alloying composition exhibit the least mass increases within the duration of the experiments. But enhanced concentrations of the dissolved elements Nb and Ti in the matrix have been found to reduce the solubility of the matrix with regard to carbon, and thus protect the material from carburization. (orig.) With 66 figs., 16 tabs

  15. 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.

  16. Development and properties of new 10Cr-2Mo-V-Nb heat resisting steel

    For the development of a new ferritic heat resisting steel which shows excellent characteristics in creep rupture strength, weldability, resistance to oxidation, and corrosion resistance to sodium and steam at the service temperature of 5000 to 6000C, extensive studies have been carried out. The main results are as follows: (1) 0.05C-10Cr-2Mo-0.1V-0.05Nb steel is obtained, whose creep rupture strength at 6000C is superior to that of SUS 304 (18-8 stainless steel). (2) This steel comprises two phases: delta-ferrite and tempered martensite. Main precipitates after longer term at 6000 to 7000C are M23C6 and Fe2Mo. Fe2Mo, a stable precipitate in ferrite, contributes to the creep rupture strength at longer term. (3) Ferritic heat resisting steel of this type is promising not only for the boiler tube use but for the fast breeder reactor steam generator use, since it has excellent high temperature strength and the resistance to oxidation and corrosion. (author)

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

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

    2015-11-01

    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.

  18. Performance of a Heating Block System Designed for Studying the Heat Resistance of Bacteria in Foods.

    Kou, Xiao-Xi; Li, Rui; Hou, Li-Xia; Huang, Zhi; Ling, Bo; Wang, Shao-Jin

    2016-01-01

    Knowledge of bacteria's heat resistance is essential for developing effective thermal treatments. Choosing an appropriate test method is important to accurately determine bacteria's heat resistances. Although being a major factor to influence the thermo-tolerance of bacteria, the heating rate in samples cannot be controlled in water or oil bath methods due to main dependence on sample's thermal properties. A heating block system (HBS) was designed to regulate the heating rates in liquid, semi-solid and solid foods using a temperature controller. Distilled water, apple juice, mashed potato, almond powder and beef were selected to evaluate the HBS's performance by experiment and computer simulation. The results showed that the heating rates of 1, 5 and 10 °C/min with final set-point temperatures and holding times could be easily and precisely achieved in five selected food materials. A good agreement in sample central temperature profiles was obtained under various heating rates between experiment and simulation. The experimental and simulated results showed that the HBS could provide a sufficiently uniform heating environment in food samples. The effect of heating rate on bacterial thermal resistance was evaluated with the HBS. The system may hold potential applications for rapid and accurate assessments of bacteria's thermo-tolerances. PMID:27465120

  19. 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.)

  20. 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 = 4.38×107 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.

  1. 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

  2. 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

  3. 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)

  4. Biaxially aligned YSZ and CeO2 buffer layers on hastelloy prepared by magnetron IBAD

    Full text: The development of high-current, flexible superconducting YBCO tapes is based on a metal substrates overcoated with a biaxially aligned oxide buffer layer to serve as a template for the epitaxial growth of c-axis oriented Yba2Cu3O7 thin films. A secondary function of the buffer is to act as a diffusion barrier to metal species to prevent them from poisoning the superconducting film. Widely studied oxide buffer layers include yttria-stabilised zirconia (YSZ) and cerium oxide (CeO2) produced by ion-beam-assisted deposition (IBAD). We have combined IBAD with magnetron sputtering to deposit biaxially aligned YSZ and CeO2 on Hastelloy C276 substrates held at room temperature. The ion beam is directed at 55deg to the normal of the film plane. In addition, we achieved room temperature epitaxial growth of CeO2 films on IBAD YSZ films by bias sputtering to form biaxially aligned CeO2/YSZ bilayers. The crystalline quality and inplane orientation of the films (200 nm thick) were investigated by x-ray diffraction techniques including ω and φ scans and pole figures. The IBAD YSZ and CeO2 films have a (111) pole in the ion beam direction with a full width at half maximum, FWHM = 24 - 30 deg; the CeO2/YSZ bilayer is similarly aligned with FWHM = 32 deg

  5. Scorpion venom heat-resistant protein decreases immunoreactivity of OX-42-positive microglia cells in MPTP-treated mice

    Shengming Yin; Deqin Yu; Xi Gao; Yan Peng; Yanhui Feng; Jie Zhao; Yiyuan Tang; Wanqin Zhang

    2008-01-01

    BACKGROUND: Microglia function as the immune surveyors of the brain under normal physiological conditions. However, microglia become activated in response to brain injuries and immunological stimulation. OBJECTIVE: To explore the influence of scorpion venom (SV) heat-resistant protein on frontal cortex and hippocampal microglia cells in a mice model of Parkinson's disease. DESIGN, TIME AND SETTING: Randomized, controlled, cellular immunity study. The experiment was performed at the Physiology Department Laboratory in Dalian Medical University between June 2005 and July 2008. MATERIALS: Ninety-six healthy, C57BI/6 mice; 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) from Sigma, USA; SV heat-resistant protein (Experimental Base Institute in Dalian Medical University). The mice were randomly divided into tour groups (n = 24): normal control, negative control, model, and SV heat-resistant protein. METHODS: Mice in the model and SV heat-resistant protein groups were subcutaneously injected with MPTP (20 mg/kg) to model Parkinson's disease, while the normal control and negative control groups were injected with physiological saline in the neck for 8 successive days. In addition, mice in the model and normal control groups were intraperitoneally injected with physiological saline 2 hours following administration, while SV heat-resistant protein and negative control groups were injected SV heat-resistant protein (0.01 mg/kg). MAIN OUTCOME MEASURES: Immunoreactivity of microglia cells in MPTP-treated mice. RESULTS: Compared with normal control mice, MPTP-treated mice displayed increased OX-42 expression in the brain. However, in the SV heat-resistant protein-treated mice, OX-42 expression was decreased, compared to the model group. In the model mouse group, the number of OX-42-positive microglia was increased in the frontal cortex, caudatum, and hippocampal hilus, compared to the normal control mice (P < 0.01). However, in the SV heat-resistant protein-treated mice

  6. Research of structural concept to heat-resistant airframe of HOPE. HOPE tainetsu kozo gainen no kenkyu

    Yamamoto, M.; Matsushita, T.; Atsumi, M. (National Space Development Agency, Tokyo (Japan))

    1991-11-05

    This paper states the concept of a heat-resistant structure of the HOPE airframe having a 10 ton weight when lifting off and also the research situation of heat-resistant structural materials. To study the structure, established are design conditions for lift-off, reentry to the atmosphere and landing. As to the load condition, the load at the time of lift-off is most critical. Relating to the temperature environment condition, thermal analysis is made of the time when a HOPE is on the orbit (low-temperature range) and reenters the atmosphere (high-temperature range), when the temperature environment is critical. The analysis shows that the temrerature environment is in a {minus}80-1700{degree}C (range). The heat-resistant structural materials are developed so as to meet these conditions. The paper describes distribution of the airframe surface temperature by aerodynamic heating at the reentry, conceptual figures of the airframe structure and structural materials. Results of the study of heat-resistant structural materials indicate an outlook for fabrication technique of a small-size component. Using thermal/temperature environment conditions, strucutre patterns and characteristics values of applied materials, a structure conceptual design model (a finite element model) is made, the analyses of the structure and heat resistance are conducted and a possibility of formation of the model is obtained. 4 refs., 13 figs., 5 tabs.

  7. 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

  8. 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.

  9. 哈氏合金C4材料焊接工艺%Research on Welding Process of Hastelloy C4

    赵瑞辉

    2014-01-01

    To prevent from the corrosion of the medium,hastelloy C4 material belonging nickel -based corrosion resistant alloy of Ni-Cr-Mo type with single-phase austenite was selected and adapt as the bottom of residual liquid tanks.With TIG welding method and ERNiCrMo -7 welding filler,the tech-niques were adapt such as groove design,pre-weld cleaning,temperature control between channels and lower welding heat.welding procedure qualification test has been passed and the metallographic micro-structures analysis of welded joints were conducted.The results show that the welding process can ensure the mechanical properties and corrosion resistance of welded joints.%为防止介质腐蚀,残液罐产品底部选用了哈氏合金C4材料,该材料属于Ni-Cr-Mo类型镍基耐蚀合金、单相奥氏体组织,具有镍基耐蚀合金的焊接特性。采用氩弧焊方法,选用ERNiCrMo-7焊丝,通过设计坡口、焊前清理、控制道间温度、选择较小焊接热输入等工艺措施,经焊接工艺评定试验和焊接接头金相组织分析,结果表明所制定的焊接工艺可以保证焊接接头的力学性能和耐蚀性能。

  10. 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

  11. 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.

  12. Preparation of flexible and heat-resisting conductive transparent film by the pyrosol process

    A pyrosol process was successfully applied for the preparation of a flexible, conductive, and transparent inorganic film, a tin-doped indium oxide (ITO) film lined with a thin mica layer. This flexible heat-resistant ITO-mica film exhibited high conductivity and transparency, comparable to ITO deposited on glass substrate. The minimum radius of bending for the film, without any recognizable change in the conductivity and appearance, was 8 mm. The ITO deposited on mica showed a large (222) diffraction peak with a smaller (400) peak, in contrast to ITO deposited with (400) orientation on an ordinary glass substrate. Using the ITO-mica film, a prototype model of a flexible organic light emitting diode was fabricated

  13. Development of halogen-free, heat-resistant, low-voltage wire for automotive use

    The environmental load of our motorized society is of major concern, and includes considerations of recycling of automotive parts as the industrial wastes. The total average length of AV, AVX (electrical wire insulated with PVC, cross-linked PVC), and AEX (electrical wire insulated with cross-linked polyolefin) wires required for the harnesses in modern automobiles is approximately 2,000-3,000 meters per unit. However these electrical wires contain a large amount of halogen, which can generate the smoke and corrosive gas. In response to this problem the authors have developed the electron beam irradiated halogen-free, heat-resistant, low-voltage electrical wire which does not contain any halogen based polymer or flame retardants. The developed wire features the reliability equivalent to AEX wire with minimum environmental load. (Author)

  14. 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.

  15. 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

  16. Heat resistance and phase composition of Ti-Si coatings on niobium

    Specific features of formation of Ti-Si diffusion coatings on refractory metal substrates were investigated with the aim of enhancement of their heat resistance in the air. For niobium coating the mixtures of titanium with titanium silicides and fluoride activators served as diffusion sources. Diffusion saturation was carried out int he range of 1000-1200 deg C. It is shown that when using diffusion sources with high Si activity the diffusion layer on niobium fits the composition of (Nb, Ti)Si2 and can be both single phase and heterophase depending on activity ratio of components. The maximal operating temperature of Ti-Si system coatings in the air reaches 2000 deg C. 3 refs.; 2 figs

  17. Structure and heat-resisting properties of slurry-diffusion coating on niobium

    The Fe-Ti-Si coatings of niobium obtained by slurry-diffusion method are studied for their phase composition and heat- resistance in the air up to 1300 deg C. A multilayer structure of the coating consists of a zone of niobium silicides Nb5Si3 and NbSi2; separated by a layer of binary silicide Nb7Fe3Si6, as well as of the zone of titanium and iron silicides. It is established that the coatings are high-resistant due to a specific structure of films formed under their oxidation. The films consist of the SiO2 matrix and fillers, simple and binary Ti, Nb and Fe oxides. The loss of protecting properties by coatings is connected with the consumption of the titanium and iron silicides external layer

  18. 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. (Procedia Engineering. 74). ISSN 1877-7058. [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

  19. Multiplexed Optical Transmission System For Automobiles Using Polymer Fiber With High Heat Resistance

    Sasayama, Takao; Asano, Hideki; Taketani, Noriaki

    1989-02-01

    A multiplexed optical transmission system for automobiles utilizing newly developed polymer fiber has been proposed. The system is composed with a star-shaped optical network, in which the ootical signals can be transmitted bi-directionally through polymer optical fiber and optical branches with the central and local controllers. The polymer fiber has been developed for this purpose in order to overcome the conventional problems which prevented its wide use for a long time. The new polymer fiber is fabricated with a thereto-setting resin for core which is pushed out from heating furnace after the process of polymerization. The fiber shows the desirable characteristics for this application, that is, the heat resistance is as high as 200°C, and the transmission loss is as low as 0.5003/m at 660 nm wavelength.

  20. 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

  1. HEAT-RESISTANT PYRIDINE-BASED POLY(ETHER-ESTER)S: SYNTHESIS,CHARACTERIZATION AND PROPERTIES

    Shahram Mehdipour-Ataei; Ali Mahmoodi

    2013-01-01

    A pyridine-based diacid was synthesized via nucleophilic substitution reaction of 4-hydroxy benzoic acid with 2,6-dichloropyridine in the presence of potassium carbonate.The diacid was characterized using FT-IR and 1H-NMR spectroscopic methods and also with elemental analysis.Polycondensation reaction of the diacid with different diols including 1,4-dihydroxy benzene,1,5-dihydroxy naphthalene,bis-phenol A and bis-phenol-P resulted in preparation of pyridine-based poly(ether-ester)s.The polymers were characterized and their physical and thermal properties including inherent viscosity,molecular weight,solubility,thermal stability,thermal behavior and crystallinity were studied.They revealed high heat-resistance and improved solubility in polar solvents.Structure-property relations for the prepared polyester were also studied.

  2. 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)

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

    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 γ-ray spectrum are reported. (author)

  4. Experience of application of a heat-resistant coating to protect billets in heating for metal forming

    Radyuk, A. G.; Titlyanov, A. E.; Glukhov, L. M.

    2015-12-01

    The purpose of the work is to search for heat-resistant coatings for titanium and steel billets upon heating for metal forming. A water-based heat-resistant coating, which has an operating temperature of 1200°C and a binder consisting of an acrylic emulsion with additions of colloidal graphite, bentonite, and an aluminum powder, is studied. This coating favors a decrease in the thickness of the defective surface layer that forms when titanium and steel billets are heated for metal forming.

  5. Heat resistance of dermatophyte's conidiospores from athletes kits stored in Nigerian University Sport's Center.

    Essien, J P; Jonah, I; Umoh, A A; Eduok, S I; Akpan, E J; Umoiyoho, A

    2009-03-01

    The incidence and heat resistance of conidiospores produced by dermatophytes isolated from athlete's kits (canvasses, stockings and spike shoes) stored in Nigerian University Sport's Centre were investigated. Epidermophyton floccosum, Microsporum oudouinii, Microsporum canis, Trichophyton concentricum, Trichophyton mentagrophytes and Trichophyton rubrum were isolated and their incidence on the athlete's kits varied with the species and type of kits. Among the isolates T. mentagrophytes, T. rubrum and E. floccosum with 25%, 23% and 20% prevalence rates respectively, were the most common isolates, and are often associated with tinea pedis (athletes foot). Canvasses with the highest incidence of dermatophytes (25 out of 34 fungal isolates) were the most contaminated kits and could serve as effective articles for the transmission of tinea pedis among athletes in Nigeria. The common etiological agents screened, produced asexual spores (conidiospores) that exhibited high resistance to heat treatment at 80 degrees C. Of the three isolates, E. floccosum, with a decimal reduction time (D-value) of D80 = 4.4 min was the most resistant followed by T. mentagrophytes with D80 = 4.0 min and then T. rubrum with D80 = 3.2 min. The spores elimination pattern indicates that increasing the heating duration would decrease the decimal reduction time and possibly denature the fungal propagules but may damage the skin during treatment with hot water compresses. The findings have shown that the use of hot water compresses is palliative but heat treatment especially vapour-heat treatment offers adequate preventive measures if applied for periodic treatment of contaminated kits. However, determining the correct condition for effective decontamination will require detailed understanding of the heat resistance of fungal spores. Otherwise treatment of kits with detergent and chaotropic agent such as urea and guanidinium salt is preferred to heat treatment. PMID:19388558

  6. 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.

  7. Influencia de la pulpa lixiviada sobre el desgaste de una aleación del tipo Hastelloy C 276

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

    2016-01-01

    Las bombas usadas en la industria niquelera cubana para trasegar pulpas lixiviadas se fabrican de una aleación del tipo Hastelloy C 276. Se hicieron análisis macroscópicos del cuerpo de la voluta para determinar defectos superficiales de la misma por efecto de la corrosión. En otras muestras se realizaron ensayos microscópicos y de microdureza. Las microestructuras revelan que la voluta sufre un proceso de abrasión por arranque y pérdida de material de la superficie interna de la misma, con l...

  8. Etude expérimentale du soudage par laser YAG de l'alliage base nickel Hastelloy X

    Graneix, Jérémie; Béguin, 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.

  9. 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

  10. Physiological quality and gene expression related to heat-resistant proteins at different stages of development of maize seeds.

    Andrade, T; Von Pinho, E V R; Von Pinho, R G; Oliveira, G E; Andrade, V; Fernandes, J S

    2013-01-01

    We quantified and characterized the expression of heat-resistant proteins during seed development of maize lines with distinct levels of tolerance to high drying temperature. A corn field was planted for multiplication of seeds of different lines, two tolerant and two non-tolerant to high drying temperatures. Harvest of the seeds was carried out at various stages of development and they were then subjected to tests of moisture content, germination, first count of germination, accelerated aging, and cold test. The seeds were stored in a freezer for later analysis of expression of heat-resistant proteins by means of real-time PCR, electrophoresis, and spectrophotometry. We observed that heat-resistant proteins are expressed in a differential manner in seeds from different lines and at different stages of development. The expression of heat-resistant proteins was earlier in lines tolerant to high drying temperatures. Greater germination and vigor values was found for seeds collected at the last stage of development. PMID:24085427

  11. 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.

  12. Molybdenum-boron-silicon coating on VN-3 niobium alloy

    Heat resistance of the complex molybdenum-boron-silicon coating on VN-3 niobium alloy is studied. The coating phase composition in the initial state and after heating in air at 1200 deg C during 100-1300 h is determined using X-ray diffraction, electron diffraction and X-ray spectrum analyses. It is shown that high heat resistance of the coating is ensured due to formation of an external film of silicon oxide and a boride sublayer between the metal and coating

  13. Microstructural evolution in austenitic heat-resistant cast steel 35Cr25Ni12NNbRE during long-term service

    The microstructural evolution of austenitic heat-resistant cast steel 35Cr25Ni12NNbRE during aging and long-term service was investigated using optical microscope (OM), X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The microstructure of the as cast steel consists of the dendritic austenite, the block-like eutectic carbide M7C3 spreaded among austenitic dendrite, and a small quantity of M23C6 carbide. The microstructure of the steel aged at 600 deg. C consists of eutectic carbide M23C6 transformed from eutectic carbide M7C3 and dendritic austenite in which fine secondary carbide particles M23C6 precipitated. The precipitated carbide M23C6 kept a cubic-cubic orientation relationship (OR) with austenite matrix. There existed a carbide precipitation free zone (PFZ) around the eutectic carbide. For the long-term serviced samples, the secondary carbide precipitated in the austenite strikingly increased and the PFZ disappeared. Part of the M23C6 transformed into M6C, which always kept a twin OR, [114]M6C//[110]A//[110]M23C6, with the austenite and the M23C6 secondary carbide. In addition, a small quantity of σ phase FeCr and ε-Cr2N were also identified. The effects of alloy composition and service condition on the microstructural evolution of the steel were discussed.

  14. 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...

  15. Investigation of the isothermal precipitation behaviour of nickel-base alloys using electrochemical phase extraction

    Electrochemical phase extraction methods have been developed empirically for the selective separation of the precipitates in metallic materials. A detailed description of the process has been undertaken to allow optimization for various nickel-base alloys. For this part of the investigation, 16 model alloys were prepared as test electrodes and the electrolyte composition was varied over a wide range. The results enabled a series of effects to be explained on the basis of electrochemical data. The large number of test parameters limited the scope of the preliminary experiments and the range of model alloys used. In the nickel-base alloys, titanium carbo-nitride and primary M6C precipitates were identified. During isothermal ageing, M23C6 (except in Alloy KSN), Ni3Al (in INCONEL 617), Laves phases (in Hastelloy X and INCONEL 617), M12C (in HASTELLOY X and INCONEL 617) and α-tungsten (in the tungsten-containing alloys) were precipitated. The precipitation behaviour changed in the alloys investigated from intracrystalline to intercrystalline with increasing ageing temperature. The intracrystalline secondary precipitations affect the microhardness, structure and the solid-solution lattice. (orig.)

  16. Deformation behaviour in advanced heat resistant materials during slow strain rate testing at elevated temperature

    Mattias Calmunger

    2014-01-01

    Full Text Available In this study, slow strain rate tensile testing at elevated temperature is used to evaluate the influence of temperature and strain rate on deformation behaviour in two different austenitic alloys. One austenitic stainless steel (AISI 316L and one nickel-base alloy (Alloy 617 have been investigated. Scanning electron microscopy related techniques as electron channelling contrast imaging and electron backscattering diffraction have been used to study the damage and fracture micromechanisms. For both alloys the dominante damage micromechanisms are slip bands and planar slip interacting with grain bounderies or precipitates causing strain concentrations. The dominante fracture micromechanism when using a slow strain rate at elevated temperature, is microcracks at grain bounderies due to grain boundery embrittlement caused by precipitates. The decrease in strain rate seems to have a small influence on dynamic strain ageing at 650°C.

  17. Modification Approach of Fuzzy Logic Model for Predicting of Cutting Force When Machining Nickel Based Hastelloy C-276

    Basim A. Khidhir

    2010-01-01

    Full Text Available Problem statement: Most Nickel based Hastelloy C-276 is a difficult-to-machine material because of its low thermal diffusive property and high strength at high temperature. Machinability consideration of nickel based Hastelloy C-276 in turning operations has been carried out using ceramic inserts under dry conditions. Approach: This study described a modification approach applied to a fuzzy logic based model for predicting cutting force where the machining parameters for cutting speed ranges, feed rate, depth of cut and approach angle are not overlapping. For this study, data were selected depending on the design of experiments. Response surface methodology was applied to predict the cutting force and to examine the fuzzy logic based model. Results: The modification approach fuzzy logic based model produced the cutting force data providing good correlation with response surface data. In this situation the cutting force data were superimposed and results were adjusted according to their own ranges. Conclusion: A review of literatures on optimization techniques revealed that there were, in particular, successful industrial applications of design of experiment-based approaches for optimal settings of process variables.

  18. 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.)

  19. IMPROVEMENT OF TYPE IV CRACKING RESISTANCE OF 9Cr HEAT RESISTING STEEL WELDMENT BY BORON ADDITION

    M.Tabuchi; M.Kondo; T.Watanabe; H.Hongo; F.Yin; F.Abe

    2004-01-01

    Creep lives of high Cr ferritic heat resisting steel weldments decrease due to Type IV fracture, which occurs as a result of formation and growth of creep voids and cracks on grain boundaries in fine-grained heat affected zone (HAZ). Because boron is considered to suppress the coarsening of grain boundary precipitates and growth of creep voids, we have investigated the effect of boron addition on the creep properties of 9Cr steel weldments. Four kinds of 9Cr3W3CoVNb steels with boron content varying from 4.7×10-5 to 1.8×10-4 and with nitrogen as low as 2.0×10-5 were prepared.The steel plates were welded by gas tungsten arc welding and crept at 923K. It was found that the microstructures of HAZ were quite different from those of conventional high Cr steels such as P91 and P92, namely the fine-grained HAZ did not exist in the present steel weldments. Boron addition also has the effect to suppress coarsening of grain boundary carbides in HAZ during creep. As a result of these phenomena,the welded joints of present steels showed no Type IV fractures and much better creep lives than those of conventional steels.

  20. 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 43 degrees C, and showed an enhanced ability to survive at 42.6, 43.5, and 44.5 degrees C. 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 exposure to 44.5 degrees C. After 3 hr incubation at 37 degrees C, both cell lines had an identical sensitivity to further exposure to 44.5 degrees C. 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 thermoresistant variant and the parent cell line

  1. 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

  2. Design of improved heat resistant materials by use of computational thermodynamics

    Schaffernak, B.; Cerjak, H. [Graz University of Technology Institute for Materials Science, Welding and Forming, Graz (Austria)

    2001-07-01

    Ferritic-martensitic steels are widely used for high temperature applications. Compared with austenitic materials they own a better thermal conductivity, lower thermal expansion coefficient, lower costs and a better resistance against stress corrosion cracking. In this contribution the modelling of the microstructure based on thermodynamic calculations has been used for the description and further alloy design for this steel group. The results are phase diagrams showing the precipitates to be expected as well as driving forces, phase compositions and diffusion coefficients as base for further modelling activities. A calculation model based on the determination of the (calculated) transformation temperatures A{sub e1}, and A{sub e3}; and the diffusion coefficients is proposed, which can help to predict the microstructural stability and the creep strength from the chemical composition. Based on this model test melts for some new alloys has been produced. First creep tests of these alloys confirm the presented approach. (orig.)

  3. 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

  4. Study on functional heat-resistant ceramics SiC using small angle neutron scattering

    The mechanical properties of functional heat-resistant silicon carbide SiC ceramics are significantly influenced by the concentration and dimensions of pores. 3 SiC samples with different densities were sintered with different kind and amount of additives (such as Al2O3, B4C and C) using different sintering conditions of the Department of Material Science and Engineering at the University of Science and Technology in Beijing. Small angle neutron scattering measurements for 3 SiC samples were carried out at C1-2 SANS instrument of the University of Tokyo in Japan Atomic Energy Research Institute. The neutron data with 8 and 16 in of secondary flight path and 10 and 7 A of neutron wave length respectively have been obtained. After deduction of background measurement and transmission correction, both neutron data were linked up with each other. The cubic patterns of 3 neutron data with Q range from 0.0028 - 0.05 A-1 are almost with axial symmetry. It shows that the shape of pores, whose dimensions are relative to the Q range, is almost spherical. For spherical particles (or pores) we can obtain an expression of size distribution directly, using Mellin Transform (J. Appl. Phys. 45, 1974, 46.). According to our calculating program for the expression, the size distribution of pores for 3 samples were obtained. The average size (∼ 190 A) of pores for hot-pressed SiC sample with more density is smaller than others (∼ 210 A). It seems to be the reason why the density of hot-pressed SiC sample is higher than no-hot-pressed sample. (author)

  5. 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...

  6. 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

  7. Environmental temperature and physiological polymorphism of populations. II. The relation of changes in the organismal heat resistance to its initial level during heat acclimation

    Ushakov, B.P.; Amosova, I.S.; Chernokozheva, I.S.; Dregolskaya, I.N.; Pashkova, I.M.; Skholl, E.D.

    1977-01-01

    Study was made of the changes in the organismal heat resistance level and average values were obtained for clones and siblings of Hydra oligactis, Asellus acquaticus, Drosophila melanogaster, Strongylocentrotus droebachiensis (embryos) and Rana temporaria (tadpoles) during short-term heat acclimation (sibacclimation method). In all the species studied a negative correlation was observed between the initial heat resistance level of clones and siblings and its increase during heat acclimation. Reaction norm during temperature resistance acclimation of poikilotherms depends on the initial organismal heat resistance inherent in each genotype.

  8. 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.

  9. Modifications in membrane fatty acid composition of Salmonella typhimurium in response to growth conditions and their effect on heat resistance.

    Alvarez-Ordóñez, Avelino; Fernández, Ana; López, Mercedes; Arenas, Ricardo; Bernardo, Ana

    2008-04-30

    The effects of growth temperature (in the range 10-45 degrees C) and acidification up to pH 4.5 of the culture medium (Brain Heart Infusion, BHI) with different organic acids (acetic, citric and lactic) and hydrochloric acid on membrane fatty acid composition and heat resistance of Salmonella typhimurium CECT 443 were studied. The heat resistance was maximal in cells grown at 45 degrees C (cells grown in non-acidified BHI showed a D58-value of 0.90 min) and decreased with decreasing growth temperature up to 10 degrees C (D58-value of 0.09 min). The growth of cells in acidified media caused an increase in their heat resistance. In general, acid adapted cells showed D-values of between 1.5 and 2 times higher than the corresponding for non-acid adapted control cells. This cross-protection response, which has important implications in food processing, was not dependent on the pH value and the acid used to acidify the growth medium. A membrane adaptation corresponding to an increase in the unsaturated to saturated fatty acids ratio (UFA/SFA) and membrane fluidity was observed at low growth temperature. Moreover, the acidification of the growth medium caused a decrease in UFA/SFA ratio and in the C18:1 relative concentration, and an increase in cyclopropane fatty acids (CFA) content mainly due to the increase in cyc19 relative concentration. Thus, acid adapted cells showed CFA levels 1.5 times higher than non-acid adapted control cells. A significant proportion of unsaturated fatty acids were converted to their cyclopropane derivatives during acid adaptation. These changes in membrane fatty acid composition result in cells with decreased membrane fluidity. A clear relation between membrane fatty acid composition and heat resistance was observed. In general, D-values were maximum for cells with low UFA/SFA ratio, and, consequently, with low membrane fluidity. Moreover, CFA formation played a major role in protecting acid adapted cells from heat inactivation. However

  10. Oxidation protection for niobium and its alloys at high temperature

    Problems, related to increasing heat resistance of niobium and niobium-base alloys, are considered. It is mentioned, that when developing coatings to protect niobium and niobium alloy products against oxidation, one should preliminarily create a butter layer, preventing matrix interaction with the coating components, at metallic base - protective coating boundary. Depending on the temperature regime and the product application conditions, the coating can be formed on the basis of molybdenum disilicide or high-melting alloyed silicides. Besides, a composition, containing a low-melting component and high-melting filler, can be used for its creation