WorldWideScience

Sample records for heat-resistant alloy hastelloy

  1. Creep-fatigue interaction property of a nickel-base heat-resistant alloy Hastelloy XR in simulated HTGR helium gas environment

    International Nuclear Information System (INIS)

    The properties of Hastelloy XR, which is a developed alloy as the structural material for high-temperature components of the HTTR, under creep-fatigue interaction conditions were examined by performing a series of axial strain controlled fully reversed fatigue tests in the simulated HTGR helium gas environment at 700, 800, 900 and 950degC. Two types of evaluation techniques, i.e., the life fraction rule and the ductility exhaustion one, were applied for the evaluation of the creep damage during the tensile strain holding. The fatigue life reduction due to the strain holding is observed even at hold times of 6 seconds, and the saturation point of the fatigue life reduction shifts to the shorter hold time side with increasing temperature. The life fraction rule predicts an excessively conservative value for the creep damage. The ductility exhaustion rule can predict the fatigue life under the effective creep condition much more successfully than the life fraction one. (author)

  2. Multiaxial creep behavior of nickel-base heat-resistant alloys Hastelloy XR and Ni-Cr-W superalloy at elevated temperatures

    International Nuclear Information System (INIS)

    A series of uniaxial and multiaxial creep tests was carried out on Hastelloy XR and Ni-Cr-W superalloy, which were developed as the high temperature structural materials for nuclear application at the JAERI, in order to investigate multiaxial creep behavior of these materials. Norton's creep law and von Mises' flow rule were applied to the prediction of multiaxial creep behavior of a tube under some significant loading conditions. In most cases the multiaxial creep behavior of these materials were successfully described with the constitutive equations based on the material parameter fitting uniaxial creep test results, though a few exceptional cases were observed. The present study has revealed that the method based on Norton's creep law and von Mises' flow rule are basically applicable for the description of the multiaxial creep behavior for Hastelloy XR and Ni-Cr-W superalloy as the conventional design method. (author)

  3. Filler metal development for hastelloy alloy XR

    International Nuclear Information System (INIS)

    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)

  4. Heat resistant cast aluminium alloys with iron

    International Nuclear Information System (INIS)

    On the base of structural approach principal possibility of development of cheaper high-iron cast heat resisting aluminium alloys is proved. Perspective Al-Fe-Ce-Zr-Cr and Al-Fe-Ni-Zr-Cr compositions are proposed. The alloys proposed have high heat resistance, mechanical and casting properties

  5. Studies on neutron irradiation effects of iron alloys and nickel-base heat resistant alloys

    International Nuclear Information System (INIS)

    The present paper describes the results of neutron irradiation effects on iron alloys and nickel-base heat resistant alloys. As for the iron alloys, irradiation hardening and embrittlement were investigated using internal friction measurement, electron microscopy and tensile testings. The role of alloying elements was also investigated to understand the irradiation behavior of iron alloys. The essential factors affecting irradiation hardening and embrittlement were thus clarified. On the other hand, postirradiation tensile and creep properties were measured of Hastelloy X alloy. Irradiation behavior at elevated temperatures is discussed. (author)

  6. Filler metal development for Hastelloy alloy XR

    International Nuclear Information System (INIS)

    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)

  7. Micrography for heat-resisting alloys of HTGR

    International Nuclear Information System (INIS)

    The post-irradiation micrography for heat-resisting alloys of HTGR are described, which include Hastelloy X; Inconel 600, 625 and X750; and Incoloy 800 and 807. An etching technique was developed for the purpose. As candidates for the experimental VHTR (Very High temperature Reactor), the alloys were irradiated in JMTR (Japan Material Testing Reactor) at temperatures between 8000C-10000C, which was followed by post-irradiation examination in the hot laboratory. Microstructures of the alloys are given for the respective test conditions of pre-irradiation treatment, irradiation and tensile test temperature. The improved etching method enabled interpretation of the phenomena during irradiation and in post-irradiation mechanical test. (auth.)

  8. Filler metal development for Hastelloy alloy XR

    International Nuclear Information System (INIS)

    The present report describes the results of cooperative research in order to evaluate the weldability and properties of Hastelloy alloy XR weldment with the filler metal fabricated on the industrial scale. A series of qualification test was performed using the filler metal, of which the content of the minor elements such as boron was optimized on the basis of the results so far obtained by the filler metal development for Hastelloy alloy XR structure with thin wall. The boron diffusion behavior, weldability, and the properties such as corrosion, aging embrittlement and high temperature strength were examined on the Hastelloy alloy XR weldment by means of tungsten inert gas arc welding procedure. Based on the excellent weldability and weldment properties as well as the mass production possibility for the filler metal, it is concluded that the filler metals possessing the required performance has been developed. (author)

  9. Manufacture of a heat-resistant alloy with modified specifications for HTGR structural applications

    Energy Technology Data Exchange (ETDEWEB)

    Sahira, K.; Kondo, T.; Takeiri, T.

    1984-07-01

    A method of manufacturing a nuclear grade nickel-base heat-resistant alloy in application to heliumcooled reactor primary circuit components has been developed. The Hastelloy-XR alloy, a version of Hastelloy-X, was made available by combining the basic studies of the oxidation behavior of Hastelloy-X and the improvement of manufacturing techniques. In the primary and remelting steps, the choice of appropriate processes was made by performing numerical analyses of the statistical deviation of both chemical composition and the products' mechanical properties. The feasibility of making larger electroslag remelting ingots with reasonable control of macrosegregation was examined by the calculation of a molten metal pool shape during melting. The hot workability of Hastelloy-XR was confirmed to be equivalent to that of Hastelloy-X and the importance of controlling the thermal and mechanical processes more closely was stressed in obtaining a higher level of quality assurance for the nuclear applications. The possibility of enhancing the high-temperature mechanical performance of Hastelloy-XR was suggested based on the preliminary test results with the heats manufactured with controlled boron content.

  10. A View of Compatible Heat-Resistant Alloy and Coating Systems at High-Temperatures

    International Nuclear Information System (INIS)

    Conventional and advanced coatings were reviewed, and it was pointed out that the coated Ni-base superalloys decreased their creep rupture life significantly at higher temperatures, and the advanced high strength superalloy became more remarkably. Concept of diffusion barrier coating system (DBC system) and their formation process was introduced, and the results obtained for several heat-resistant alloys, stainless steel (SUS310S), Ni-Mo base alloy (Hastelloy-X), and 4th generation single crystal superalloy (TMS-138) were given. It was noted that creep-rupture life of the SUS310S and Hastelloy-X with the DBC system became longer than those of the bare alloys with or without conventional ?-NiAl coatings. This is due to slow creep-deformation of the Re-base alloy layer as the diffusion barrier. A novel concept based on combination of superalloys and coatings was proposed, by taking both the materials science and corrosion science into consideration.

  11. Alloying influence on platinum alloy heat-resistance

    International Nuclear Information System (INIS)

    For the purpose of evaluating the effect of alloying elements on the heat resistance characteristics of binary platinum alloys they have been tested for creep in an air atmosphere and in a glass melt. The intercrystallne high-temperature corrosion of alloys has been studied. The experimental and theoretical series of efficiency are presented of the strengthening effect of alloying elements in a platinum solid solution. A comparison of the theoretical and experimental series makes it possible to formulate the principal statements concerning the efficiency of strengthening of a platinum solid solution by alloying. Alloying with ruthenium, rhodium, and iridium is most efficient, alloying with gold is less efficient, and alloying with palladium is highly inefficient

  12. Production of homogeneous titanium--Hastelloy N alloys

    International Nuclear Information System (INIS)

    The modification of Hastelloy N by titanium can result in inhomogeneously distributed carbide precipitates. The metallurgical principles necessary to produce a homogeneous alloy are stated and demonstrated. It is shown that a homogeneous alloy leads to more uniform postirradiation properties and, by chance, better properties. A ''memory'' effect in the alloy is identified and shown to be caused by the inhomogeneities

  13. Compatibility of heat resistant alloys with boron carbide, (4)

    International Nuclear Information System (INIS)

    This paper relates to the compatibility test of control rod sheath (Hastelloy XR alloy) and neutron absorber (boronated graphite) for the VHTR, which has been researched and developed by JAERI. The irradiation was conducted by using the OGL-1 irradiation facility in the JMTR in order to study reaction behaviour between Hastelloy XR alloy and boronated graphite as well as to determine a reaction barrier performance of refractory metal foils Nb, Mo, W and Re. Irradiation conditions were as follows. Neutron dose : 4.05 x 1022 m-2 (E 18 m-2 (E > 0.16 pJ, 1 Mev). Helium coolant : Average temperature 855 0C, Pressure 2.94 MPa, Total impurity concentration 400 kBq/m3. Irradiation time : 5.0 Ms (1390 hours). Post-irradiation examinations i.e. visual inspection, dimensional inspection, weight measurement, metallography, hardness test, morphological observations by SEM and analysis of element distributions by EPMA were carried out. In the result, reaction products of Hastelloy XR alloy were observed in the ellipsoidal form locally. These results were same as those of the out-of-pile tests. Obvious irradiation effects were not detectable but a little accelarated increase in reaction depth of Hastelloy XR alloy by heat effect of specimens was observed. The refractory metal foils had a good performance of reaction barrier between Hastelloy XR alloy and boronated graphite. Furthermore, movement of Ni, Fe and Cr in the reaction area of Hastelloy XR alloy, difference in the reaction depth of B and C, irradiation effects on diffusion coefficient, lithium production and heat effect are discussed. (author)

  14. Heat resisting nickel alloys for engine blade building-up

    International Nuclear Information System (INIS)

    Applicability has been estimated of certain heat resisting nickel alloys with additions of carbide-stabilizing elements (Cr, Ti, V, Nb) and elements of intermetallic strengthening (Al, Ti) for weld surfacing gas turbine blades. For this purpose investigated were microstructure, heat resistance, hot hardness, scale resistance and wear of the above alloys. As a result the Kh30N50YuT nickel alloy has been developed possessing the best complex of properties that allow the material to be used for weld surfacing gas turbine blades

  15. Compatibility of heat resistant alloys with boron carbide

    International Nuclear Information System (INIS)

    The solid state compatibility of Hastelloy X and Incoloy 800 with boron carbide (B4C) were investigated at 850 - 10500C for periods of 20 - 2000 hrs for potential control rod application for Very High Temperature Gas-cooled Reactor (VHTR). These studies have shown both the alloys were incompatible with nearly stoichiometric B4C or B4C+C (70 wt% carbon) and they were less compatible with nearly stoichiometric B4C than with B4C over the temperature range 850 to 10000C. At 10500C for 100 hrs both of the alloys reacted with nearly stoichiometric B4C or B4C+C were melt by producing eutectic alloys. It was observed that boron and carbon penetration in the alloy is dominated by the grain boundary penetration. And some had a uniform reaction layer near the surface as a result of volume penetration. In general Incoloy 800 was more compatible than Hastelloy X and it was clearly seen by comparing the volume penetration depth reacted with nearly stoichiometric B4C at 9500C for 100 hrs. In Hastelloy X the depth was 225 ?m but in Incoloy 800 it was 117 ?m. The phases formed on alloys were identified to be Fe2B, Cr2B and Ni2B by X-ray diffraction. By the tensile test of reacted Hastelloy X material, it was found that the ultimate tensile strength was reduced due to the reaction of alloy with boron carbide but there was no change on the yield strength. (author)

  16. New iron base heat resisting alloys for application in high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Heat resisting steels with relatively low nickel content have been designed and tested, which showed creep strength and corrosion resistance equivalent or superior to the present prime candidate nickel base alloys. The materials are expected to substitute nickel base alloys in the applications to the components in reactor core, e.g. neutron absorber sheathing, for which most nickel rich alloys are not suited because of their susceptibility to the loss of ductility caused by thermal neutron irradiation. 12Cr-12Ni-5Mo-5Cu-iron base alloys were designed and several similar versions were prepared. Tests at high temperatures were conducted on tensile properties at up to 10000C, creep rupture properties at 700 -- 9000C, toughness after aging at 700 and 8000C and corrosion resistance in the impure helium gas at 9000C. The helium environment was prepared simulating the impurity contents in the coolant of high temperature gas-cooled reactor. After exposure test to the impure helium, changes in weight and carbon content were measured, and metallurgical analysis was made by optical microscopy, EPMA analysis and X-ray diffraction. It was found that creep rupture strength of a heat of 12Cr-12Ni-5Mo-5Cu steel with small amounts of niobium was superior to the prime candidate material, Hastelloy alloy XR and was comparable to Inconel alloy 617, although some significant decrease in toughness occurred after aging at intermediate temperatures. Weight gain due to oxidation and carbon increase due to carburization of this steel in the simulated impure helium gas were lower than those of Hastelloy alloy XR. In conclusion this alloy, with appropriate modification, can be a potential substitutional material as the structural material to be used under thermal neutron exposure. The material may also be potential for general structural applications for high temperature gas-cooled reactors, substituting the commonly used material like Incoloy alloy 800H. (author)

  17. Modern cast heat resisting alloys for gas turbine blades

    International Nuclear Information System (INIS)

    The trends in heat resistant alloys designing are reviewed as applied to Ni-Co-Cr-W-Mo-Al-Nb system alloys. Manufacture of monocrystalline items is noted to be a promising way which assures high and stable mechanical properties. The alloys intended for monorystalline casting have to contain no elements (C, B, Zr) promoting grain boundary strengthening. The features of monocrystalline casting procedure and subsequent heat treatment are also considered

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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 (?), and the permeabilities of the heat resisting alloys were between those of nickel and iron (?). 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.)

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

    International Nuclear Information System (INIS)

    Hydrogen permeability of several metals and alloys was measured in the temperature range between 2000 and 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 (?), and the permeabilities of the heat resisting alloys were between those of nickel and iron (?). 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. (author)

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

    International Nuclear Information System (INIS)

    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)

  3. Investigation of EDM characteristics of Nickel-based heat resistant alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Sin Ho; Kim, Dae Eun [Yonsei Univ., Seoul (Korea, Republic of)

    2003-10-01

    The EDM processing characteristics of one of the nickel-based heat resistant alloys, Hastelloy-X, were investigated under the various EDM conditions and analyzed in terms of surface integrity. This alloy is commonly used as a material for the hot gas path component of gas turbines and it is difficult to machine by conventional machining methods. The primary EDM parameter which was varied in this study were the pulse-on time. Since the pulse-on time is one of the main factors that determines the intensity of the electrical discharge energy, it was expected that the machining ratio and the surface integrity of the specimens would be proportionally dependent on the pulse-on duration. However, experimental results showed that MRR (Material Removal Rate) and EWR (Electrode Wear Rate) behaved nonlinearly with respect to the pulse duration, whereas the morphological and metallurgical features showed rather a constant trend of change by the pulse duration. In addition the heat treating process affected the recast layer and HAZ to be recrystallized but softening occurred in recast layer only. A metallurgical evaluation of the microstructure for the altered material zone was also conducted.

  4. Investigation of EDM characteristics of Nickel-based heat resistant alloy

    International Nuclear Information System (INIS)

    The EDM processing characteristics of one of the nickel-based heat resistant alloys, Hastelloy-X, were investigated under the various EDM conditions and analyzed in terms of surface integrity. This alloy is commonly used as a material for the hot gas path component of gas turbines and it is difficult to machine by conventional machining methods. The primary EDM parameter which was varied in this study were the pulse-on time. Since the pulse-on time is one of the main factors that determines the intensity of the electrical discharge energy, it was expected that the machining ratio and the surface integrity of the specimens would be proportionally dependent on the pulse-on duration. However, experimental results showed that MRR (Material Removal Rate) and EWR (Electrode Wear Rate) behaved nonlinearly with respect to the pulse duration, whereas the morphological and metallurgical features showed rather a constant trend of change by the pulse duration. In addition the heat treating process affected the recast layer and HAZ to be recrystallized but softening occurred in recast layer only. A metallurgical evaluation of the microstructure for the altered material zone was also conducted

  5. Studies on the quality optimization of hastelloy alloy XR

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

  8. Hafnium, zirconium and rhenium effect on stability of the structure of cast heat resistant alloys

    International Nuclear Information System (INIS)

    It is attempted to form the optimal microstructure and to attain its stability by doping heat-resistant alloys with active elements: hafnium, zirconium and rhenium. Cast heat resistant nickel-chromium base alloy containing 5% Mo, 9% Fe, 4.2% (Al+Ti), 0.05% C has been used for investigations. It is shown that introduction of additions of hafnium, zirconium and rhenium active elements promotes increase of structure stability in cast heat resistant alloys that is proced by increase of solidus temperature, hardening of intergrain space, inhibition of diffusion processes and fracture at grain boundaries

  9. Hafnium, zirconium and rhenium effect on stability of the structure of cast heat resistant alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nagin, A.S.; Gadalov, V.N. (Komsomol' skij-na-Amure Politekhnicheskij Inst. (USSR))

    1982-01-01

    It is attempted to form the optimal microstructure and to attain its stability by doping heat-resistant alloys with active elements: hafnium, zirconium and rhenium. Cast heat resistant nickel-chromium base alloy containing 5% Mo, 9% Fe, 4.2% (Al+Ti), 0.05% C has been used for investigations. It is shown that introduction of additions of hafnium, zirconium and rhenium active elements promotes increase of structure stability in cast heat resistant alloys that is proced by increase of solidus temperature, hardening of intergrain space, inhibition of diffusion processes and fracture at grain boundaries.

  10. Heat resistant nickel alloys modified with hafnium and zirconium

    International Nuclear Information System (INIS)

    Alloys ZhS6U-VI and ZhS3DK-VI modified separately and in combination with zirconium (0.05 %) and hafnium (0.5 %) are under study. It is established that combined alloying increases strength and plastic properties of the alloys. It is shown that alloy ZrS6U-VI tested for a long-term rupture strength demonstrates a rise in microhardness and ?-phase precipitation in the form of lamellar and needle-like particles. Hafnium alloying promotes an increase of lamellar ?phase content whereas zirconium alloying results in needle-like ?-phase formation

  11. Creep and tensile properties of alloy 800H-Hastelloy X weldments

    International Nuclear Information System (INIS)

    Hastelloy X and alloy 800H were joined satisfactorily by the gas tungsten arc welding process with ERNiCr-3 filler and the shielded metal arc welding process with Inco Weld A filler. Test specimens were of two types: (1) made entirely of deposited Inco Weld A and (2) machined transverse across the weldments to include Hastelloy X, filler metal (ERNiCr-3 or Inco Weld A), and alloy 800H. They were aged 2000 and 10,000 h and subjected to short-term tensile and creep tests. Inco Weld A and ERNiCr-3 are both suitable filler metals and result in welds that are stronger than the alloy 800H base metal

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

    OpenAIRE

    Wielgosz, R. O.

    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.

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

    Directory of Open Access Journals (Sweden)

    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.

  14. Influence of heat-resistant coatings on the structure of alloys ZhS6K

    Energy Technology Data Exchange (ETDEWEB)

    Efimenko, L.P.

    1992-03-01

    The article investigates the influence of heat-resistant coatings based on nickel monoaluminide with additions of chromium, tungsten, silicon, carbon on the composition and structure of the alloy ZhS6K after it has been coated and subsequently held for a long time at a high temperature. 5 refs., 2 figs., 1 tab.

  15. Optimum schedules of difficult-to-form heat-resistant alloys forging

    International Nuclear Information System (INIS)

    The process of manufacturing half finished discs for hydroturbine engines from heat resistant difficulty deformed nickel, iron-nickel and cobalt alloys (EI435, EI868, VZh145-ID, EK79-ID, EK152-ID, EI826, EP648-VI) is described. The recommendations on the modes of forging the single-phase nonaging and double phase aging alloys are developed. The conclusion is made, that the first compressions of ingots shoved be accomplished by small press runs. The subsequent compressions should constituted not less than 8% during one run. The total compression of the ingot during one heating should be within the concrete alloy properties. With the purpose of obtaining uniform fine-grain structure the ingot heating during the last manufacturing cycle should be accomplished within the range of 1100-1130 deg C for the majority of heat resistant alloys

  16. Phase transformation temperature determining in nickel base heat resistant alloys

    International Nuclear Information System (INIS)

    Using the method of thermal differential analysis the temperatures of phase transitions in complex alloyed nickel base materials (KhN43MBTu, KhN56MBYuD, KhN60VMTYu, KhN62VMTYu, KhN65VMBYu, KhN77TYuR) are determined. The alloys were investigated after vacuum arc remelting and subsequent hot plastic deformation. In addition, alloy KhN56MBYuD was studied after various conversions such as electroslag remelting, centrifugal casting, powder spraying and hot isostatic pressing. Studies of thermal curves of alloys allowed to define the temperature of gamma'-phase precipitation and dissolution as well as melting and crystallization points

  17. Development of bar production of heat resisting deformable nickel base alloys

    International Nuclear Information System (INIS)

    Considered is the technique for manufacturing rods of heat-resistant deformable alloys by extrusion. Optimum extrusion conditions were determined by studying the strength and the plastic characteristics of the ZhS6KP alloy. Presented is the dependence of the mechanical properties of the alloy upon the temperature and the rate of deformation of annealed and compacted blanks. A comparative investigation of preforms of rolled and extruded rods fo ZhS6KP alloy has shown the macrostructure of preforms of extruded rods to be more homogeneous, fine-grained, whereas the durability and the plastic properties are higher than those of preforms of rolled material

  18. The effects of high-temperature exposure on the properties of heat-resistant alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jaske, C.E. [CC Technologies, Inc., Columbus, OH (United States)

    1994-12-31

    The exposure of heat-resistant alloys to high temperature can significantly change their mechanical properties. This paper presents and analyzes data on the effect of thermal exposure on the tensile and impact behavior of three cast materials -- the HK-40, HP-50, and 21Cr-32Ni-Fe alloys -- and of wrought material -- Alloy 800. The changes in tensile and impact properties caused by high-temperature exposure are reviewed. Reasons for these property changes and needs for considering them in the design, operation, and life assessment of high-temperature equipment are discussed.

  19. On the corrosion behavior and the creep rupture properties of heat resisting alloys in helium environments

    International Nuclear Information System (INIS)

    The National Research Institute for Metals in Japan was in charge of a part of the researches on heat resisting super alloys in the ''Research on direct iron-refining technology utilizing high temperature reducing gas''. The institute has performed the corrosion and creep rupture tests for such alloys in helium environment for several years. Therefore, the explanation on these tests and the problems are described, based on the findings during the tests. The impurity level in helium, the coolant for high temperature gas-cooled reactors (HTGR), is first described, which must be so low that special care must be pair for adjusting and maintaining this impurity level. There are always the problems of contamination from inside and outside of the system and of the potential change due to reactivity and buffering ability. Corrosion products, the effects of the impurity level in helium, corrosion rate, and the attempt for improving the corrosion resistance of heat-resisting alloys in helium environment are described. As for the creep rupture properties in helium, the creep rupture behavior under low oxygen potential, the effects of the quantities of H2, CO, CH4, and O2 in helium on the creep rupture time for Inconel 617, and the creep rupture properties in approximated HTGR helium are described. The results of researches obtained have greatly contributed to upgrading the level of knowledge on the corrosion and the strength at high temperature oion and the strength at high temperature of heat-resisting alloys in Japan. (Wakatsuki, Y.)

  20. On the mechanism of microaddition influence on the resistance to oxidation of heat resisting nickel alloys

    International Nuclear Information System (INIS)

    Effect of rare earth metals (yttrium, cerium, praseodymium) on resistance to oxidation of foundry heat-resisting nickel alloys ZhS6K-VI and ZhS6U-VI is considered. It is shown that two mechanisms of microaddition influence of rare earth metals on the resistance to oxidation are possible, namely: rare earth metals additions reduce the concentration of defects in the oxide and change the parameters of its crystal lattice. 5 refs., 2 figs., 4 tabs

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

    International Nuclear Information System (INIS)

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

    International Nuclear Information System (INIS)

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

  3. Surface microprofile production in electrochemical machining of heat-resistant nickel-chromium alloys

    International Nuclear Information System (INIS)

    Surface microprofiling of some heat-resistant nickel-chromium alloys by electrochemical processing in chloride and ''passivating'' electrolytes is studied. It is shown that the existence of strengthening ?'-phase in the alloy, differing in its anode behaviour from nickel-chromium matrix, brings about different roughnesses, formed during processing in different electrolytes. Processing in chlorides is accompanied by etching of grain boundaries as far as in ''passivating'' electrolytes bumps are formed on the surface which is connected with difference in velocities of anode dissolving of different phases. In increasing the current density and using mixed chloride-nitrate electrolytes one can reduce the height of microroughnesses

  4. Tension and creep design stresses of the 'Hastelloy-X' alloy for high-temperature gas cooled reactors

    International Nuclear Information System (INIS)

    To provide the design data for the Hastelloy-X alloy, the tensile and creep test data was obtained experimentally, and a number of creep data was also collected through literature surveys. All of the experimental and collected data was combined to determine a minimum design value for a tensile stress and to predict a long-term life for a creep rupture time. The design yield and ultimate tensile stress curves for the Hastelloy-X alloy were determined by a best fitting all of the data up to 1000 deg. C. Creep master curves based on the Larson-Miller parameter were obtained for the standard deviations of 1?, 2? and 3?. The creep-rupture life for up to 105 h was predicted for the Hastelloy-X alloy

  5. Effects of thermal neutron irradiation on ductility of austenitic heat resisting alloys for HTR application

    International Nuclear Information System (INIS)

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

  6. Heat-resistant coatings for niobium and niobium-base alloys (review)

    International Nuclear Information System (INIS)

    The author shows that it is possible to formulate the directions in developments whose purpose is to increase the heat resistance of niobium and niobium-base alloys. These include the creation of a barrier layer for retarding undesirable diffusion processes at the coating-base interface, the formation on niobium alloy parts of alloy silicide layers, the obtaining on parts operating at temperatures above 1300 C of a coating of molybdenum disilicide, the application to previously siliconized niobium alloys of a barrier layer of heterophase coatings, the matrix of which is a low-melting component and the filler refractory compounds, and the addition to the oxidizing gaseous medium of various additions increasing the service life of the protective coating

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

    International Nuclear Information System (INIS)

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

  8. Studies on the permeation of Hydrogen and Tritium through heat resistant alloys

    Science.gov (United States)

    Schmidt, A. S.; Verfuss, F.; Wicke, E.

    1985-04-01

    At temperatures of 750 to 950°C the permeation of hydrogen through bare, heat resistant alloys was studied from 1 to 40 bar, the diffusion and permeation of tritium in the partial pressure range of 10 -4 bar. Among the alloys studied were Incoloy 800, 800 H, 802, Inconel 617, 625, the Ni-based alloy Nimonic PE 13, and several non-commercial steels. At a given temperature, the permeation rate through samples with clean surfaces — substantially free of oxide films — was found to be proportional to the square root of the hydrogen pressure. The C and the Cr contents of the steels investigated proved to exert a strong influence on the activation energies of diffusion and permeation. In some alloys a reduction of the permeation rate was observed that can be attributed to the precipitation of intermetallic phases. In one case a decrease of the permeation rate occurred during the measurements due to a phase transformation.

  9. The welding metallurgy of HASTELLOY alloys C-4, C-22, and C-276

    Science.gov (United States)

    Cieslak, M. J.; Headley, T. J.; Romig, A. D.

    1986-11-01

    The welding metallurgy (solidification and solid state transformations) of HASTELLOY* Alloys C-4, C-22, and C-276 has been determined. Varestraint hot-cracking tests performed on commercial alloys revealed a weldability ranking as follows: C-4 > C-22 > C-276. All alloys would be expected to have good weldability, with Alloy C-4 having a very low hot-cracking tendency, comparable to 304L stainless steel. Microstructures of gas-tungsten-arc welds of these alloys have been characterized by scanning electron microscopy and analytical electron microscopy. Intermetallic secondary solidification constituents have been found associated with weld metal hot cracks in Alloys C-276 and C-22. In Alloy C-276, this constituent is a combination of P and ? phases, and in Alloy C-22, this constituent is composed of ?, P, and ? phases. With phase composition data obtained by AEM techniques and available ternary (Ni-Cr-Mo) phase diagrams, an equivalent chemistry model is proposed to account for the microstructures observed in each alloy's weld metal.

  10. Importance of microalloying in providing required properties of nickel heat resisting alloys

    International Nuclear Information System (INIS)

    Considered are the problems related to the development and practical use of the processes in which traces of boron are added to the nickel alloys. The importance of boron for the increase of the properties of the heat-resisting Ei-437, ZhS3, ZhS6K, etc. nickel alloys. It is shown that boron is a good deoxidizing agent. However, its basic importance lies in the fact that it strengthens the granule boundaries, retards the diffusion processes. Therefore, it should certainly remain in the metal in the required quantities. The optimum quantities of boron depend on the alloying, therefore, they should be determined by experiment in each case. Also considered is the joint adding of the boron and zirconium traces, and rare-earth elements

  11. Boron and Zirconium from Crucible Refractories in a Complex Heat-Resistant Alloy

    Science.gov (United States)

    Decker, R F; Rowe, John P; Freeman, J W

    1958-01-01

    In a laboratory study of the factors involved in the influence of induction vacuum melting on 55ni-20cr-15co-4mo-3ti-3al heat resistant alloy, it was found that the major factor was the type of ceramic used as the crucible. The study concluded that trace amounts of boron or zirconium derived from reaction of the melt with the crucible refactories improved creep-rupture properties at 1,600 degrees F. Boron was most effective and, in addition, markedly improved hot-workability.

  12. Mastering of stampings of heat resistant nickel base alloys of improved quality

    International Nuclear Information System (INIS)

    The process of manufacturing discs from heat resistant nickel base alloys (EI698-BD) is described. The technological scheme includes creation of ingots by a vacuum-arc melting, forging, surfacing, cutting, upsetting, ultrasound control, preliminary and finite stamping and thermal treatment. The levels of mechanical properties (strength limit, fluidity level, impact strength, relative change, relative constriction) after twofold quenching (at 1100 deg C, 8 hours, and 1000 deg C, 4 hours), cooling in the air and twofold aging (at 775 deg C, 16 hours and 750 deg C, 8 hours) meet the requirements of technical conditions

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

    International Nuclear Information System (INIS)

    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 resil electrode atom probe. The corrosion resistance of this alloy in HCl at 52oC and H2SO4 at 79oC was found to be similar to N06022 alloy and better than N07725 alloy. The yield strength of this alloy and N06022 were similar in the mill annealed condition. After the age hardening treatment, the 0.2% yield strength of the HASTELLOY C-22HS alloy increased from 222 to 542 MPa. The tensile elongation and the reduction in area of the age hardened alloy were 40% and 50%, respectively at room temperature and 48% and 66%, respectively at 595oC. Atom probe tomography of the HASTELLOY C-22HS alloy revealed that the microstructure consisted of fine (?10-30 nm diameter) approximately spherical molybdenum-enriched Ni2(Cr, Mo) precipitates in an aluminum-, iron-, silicon-, and manganese-enriched matrix. The morphology of these precipitates was significantly finer than the lenticular Ni2(Cr, Mo) precipitates previously observed in a HAYNES 242 alloy. Ref. 1 (author)

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

    International Nuclear Information System (INIS)

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

  15. Creep behavior of Hastelloy X, 2 1/4 Cr--1 Mo steel, and other alloys in simulated HTGR helium

    International Nuclear Information System (INIS)

    Creep tests on several materials both in environments of air and in helium containing small amounts of H2, CH4, CO, and H2O are reported. Tests have been run on Hastelloy X at 650 to 8700C for times to 20,000 h, and although it does carburize in helium, its creep properties are very similar in both environments. Tests have been run on 2 1/4 Cr--1 Mo steel at 482 to 6500C for times to 20,000 h, and its creep strength is less in helium than in air, likely because of the decarburization that occurs in helium. Limited creep tests have been run on 9 Cr--1 Mo steel, alloy 800H, Hastelloy S, and alloy 617. The results show no large environmental creep effects but are insufficient to conclude that such effects do not exist. A test sample of Ni-7% Cr-12% Mo-4% Fe-2% Ti completely resisted carburization under conditions where Hastelloy X increased in carbon content from 0.0993 to 0.436%. Most of the creep tests described in this report are continuing. Samples of Hastelloy X and alloy 617 for subsequent testing are aging; one set has accumulated 17,000 h in air, and one set has accumulated 7000 h in helium

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

    International Nuclear Information System (INIS)

    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 ?g/cm2 and ceased when the diffusing carbon reached the center of the specimen

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

    OpenAIRE

    Ohnuma I.; Kainuma R.; Ishida K.

    2012-01-01

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

  18. Prediction of the high-temperature creep behavior for Hastelloy-X alloy

    International Nuclear Information System (INIS)

    The nickel-based Hastelloy X alloy is one of the candidate materials for structural components of the High Temperature Gas-cooled Reactor (HTGR). Its creep data was obtained from the creep tests under several stress levels at 950 .deg. C, and using this data, the creep behavior was investigated by the ?-projection model. The proper fitting range was determined from the creep curves at any stress level because the ?1-parameters are dependent on a fitting strain range. A stress dependency for the ?-parameters was established to accurately predict the creep curve of a low stress level. The time to 1%-low strains was predicted for various stress levels, and the ratios between the time to 1%-low strain and time to rupture were lower than 15%. Also, a predicted minimum creep rate revealed a good agreement with the experimental data

  19. Application of PSCPCSP program for optimization of series-produced compositions and development of new heat resistant nickel base alloys

    International Nuclear Information System (INIS)

    The PSCPCSP computer program was applied for evaluation of changes in phase compositions, structure, mechanical and physical properties of 350 series-produced cast and deforming nickel base alloys with equiaxial, columnar and monocrystal structures by their alloying within standard compositions. Results of such calculations for a number of alloys (EI893L, ZhS6K, ZNKT, EP957, EP539LMU, ChS-104, etc.) by their alloying at the minimum, medium and maximum level within the limits of their brand compositions are presented. It is shown that the above program may be useful in developing new heat-resistant alloys. 11 refs., 8 tabs

  20. Elastic plastic fracture toughness values for a hastelloy alloy sample submitted to a static load

    International Nuclear Information System (INIS)

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

  1. Corrosion of heat resistant alloys in pressurized helium at elevated temperature

    International Nuclear Information System (INIS)

    Using Hastelloy X, Incoloy 800 and Inconel 617, high temperature corrosion tests in 40 atg helium gas were carried out at the temperatures ranging from 800 to 1,0000C for durations up to 1,000 h. The results were compared with those obtained in 1 atg helium gas, the composition of which was about the same as that of the 40 atg helium gas. Various types of corrosion behavior including general corrosion, intergranular penetration and depletion of alloying elements near the surface were investigated for comparison. For the test environment a helium-based gas mixture was used, of which composition was proposed by Japan Atomic Energy Research Institute. The main results are summarized as follows: At temperature below 9000C, little difference between corrosion at high pressure and that at low pressure was found. Probable reason for this is that these two environments have the same oxidation potentials and low carburizing conditions as well as low decarburizing conditions. At 1,0000C, however, considerable difference was observed owing mainly to the difference in decarburization. (author)

  2. The mechanism of elevated temperature intergranular cracking in heat-resistant alloys

    International Nuclear Information System (INIS)

    Research highlights: ? The segregation concentration is much higher in dimples that at grain boundaries. ? The prominent segregation of tin and tellurium is observed during rupture test. ? The cracking initiates at the grain boundary carbide interface. - Abstract: Reheat or stress relief cracking phenomena have been reassessed in 2.25Cr1.5W heat-resistant alloys. During rupture test, time to intergranular failure increases with decreasing temperature and tensile stress and is shorter in the alloy containing a higher bulk content of phosphorus. Also the time to intergranular failure can be expressed by t = t0.?-n.exp(Q/RT) where t0 is the proportional constant, n the stress exponent and Q the activation enthalpy. Matrix softening is accelerated under tensile stress and an active carbide growth occurs at grain boundaries oriented normal to the tensile stress direction. Because impurities segregate actively to dimples frequently observed at reheat intergranular fracture surfaces, the dimples are not micro-ductile fracture areas but the grain boundary carbide interfaces. The segregation concentration of the impurities is much higher at the grain boundary carbide interfaces than the carbide-free grain boundaries. The phosphorus segregation at the carbide interfaces of the alloy containing the higher bulk content of phosphorus is mainly replaced by the segregation of nitrogen, tin and tellurium in the alloy containing a lower bulk cone alloy containing a lower bulk content of phosphorus. The elevated temperature intergranular cracking under tensile stress occurs finally due to the carbide-free grain boundary cracking following the decohesion of the grain boundary carbide interfaces.

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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)

  5. Effects of cyclic aging on mechanical properties and microstructures of hastelloy alloy X

    International Nuclear Information System (INIS)

    In attempt of application to the high temperature structural components for the very high temperature gas cooled-reactor (VHTR), microstructural stability of Hastelloy alloy X and its influence to the room temperature toughness were investigated. The mechanical property changes, particularly aged by thermal cycling to be expected in the reactor operation were examined by tensile tests, Charpy impact tests, hardness tests, EPMA analysis and TEM observation. In addition to isothermal aging, cyclic aging was given up to 125 cycles with peak temperature at 700 -- 10000C. Holding time was given for 8 hours at each peak temperature so that total accumulated time at the peak reached 1000 hours. The results indicate that the changes in ductility of the cyclically aged materials are generally enhanced relative to those of isothermally aged. The observed trend was consistent with the enhanced carbide precipitation. For the peak aging temperature up to 9000C, the ductility loss of the cyclic case is higher than that of the isothermal, while the relation is reversed at 10000C. (author)

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

    International Nuclear Information System (INIS)

    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%.

  7. Development and investigation of industrial technique for hot rolling of small cross section rods of unyielding heat resisting alloys

    International Nuclear Information System (INIS)

    A hot-rolling technology has been developed for rolling rods about 14 to 16 mm in diameter made of EI826, EI929VD, EI867VD heat-resistant nickel alloys, the rods being used for manufacturing the fastening parts and for die-forging blades. The blanks preheated up to a temperature of 1160 to 1190 deg C are rolled on ''300/450'' rolling mill in two processes according to two roll pass designs; namely, oval-round for rolling the rods 16 mm in diameter, and square-oval-round for the rods 14 mm in diameter. It is the installation of the technology of manufacturing rods of decreased diameters from the above heat-resistant alloys that yields a considerable economical effect, owing to the saving of up to 40% of an expensive metal and to the reducing of the amount of work as required for manufacturing the machine parts

  8. On correlation of fatigue resistance of heat-resisting nickel alloys during bending and tension-compression

    International Nuclear Information System (INIS)

    Presented are the results of experimental studies of fatigue resistance of heat-resisting the EhI867, VZhL12U and ZhS6K nickel alloys under conditions of symmetric cycle at rotational bending and tension - compression in the temperature range of 20 to 1000 deg C. Valued is the influence of the stressed state type of test materials on fatigue resistance depending on temperature and test base

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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%.

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

    International Nuclear Information System (INIS)

    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 ?int. The resultant dmax vs. ?int and Am vs. ?int 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)

  12. Mechanical Properties Anisotropy of Cold-Rolled and Solution-Annealed Ni-Based Hastelloy C-276 Alloy

    Science.gov (United States)

    Mehta, K. K.; Mukhopadhyay, Prantik; Mandal, R. K.; Singh, A. K.

    2014-07-01

    This work describes a correlation among texture, in-plane anisotropy in tensile properties, and yield locus in Ni-based Hastelloy C-276 alloy. The alloy exhibits moderate values of in-plane anisotropy and anisotropy index, which has been attributed to the presence of moderate overall intensity of texture. The alloy displays two slopes in true plastic stress-strain curve and follows a Ludwigson relation. At low plastic strains, the sample displays the presence of annealing twins and less strain localization at grain boundaries, while the formation of deformation twins and high strain localization within the deformation twins and at the grain boundaries are observed in a high-strained region. The 45-deg and 67.5-deg orientation samples show relatively low ductility and low work-hardening exponent. This has been explained based on dislocation storage capacity and dynamic recovery coefficient using Kock-Mecking-Estrin analysis.

  13. Creep behavior for Hastelloy-XR

    International Nuclear Information System (INIS)

    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)

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

    Directory of Open Access Journals (Sweden)

    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.

  15. X-ray fluorescence analysis of nickel-based heat-resisting alloys by matrix correction using theoretical alpha coefficients

    International Nuclear Information System (INIS)

    The study of the X-ray fluorescence analysis of main component and alloying elements in nickel-based heat-resisting alloys has been performed. The calibration curves were made by using NBS SRM's, JAERI and home-made nickel-based standard samples and the correction was made for the matrix effects using theoretical alpha coefficients. Accuracies (?d) for respective element obtained from those curves with correction were improved, especially for chromium and iron, in comparison with uncorrected ones. The relative standard deviation for each element was in the ragne of 0.25 ? 1.27 % with the exception of aluminum (0.26 Al%; r.s.d. 3.01 %). The analytical ranges were as follows; Cr(12.75 ? 26.49 %), Mo(1.09 ? 9.18 %), W(0.019 ? 4.57 %), Co(0.39 ? 8.90 %), Ti(0.35 ? 3.44 %), Al(0.15 ? 6.68 %), Nb(0.88 ? 5.38 %), Fe(0.12 ? 23.2 %), Mn(0.01 ? 0.65 %). The analytical values of nickel-based heat-resisting alloys such as Inconel 713LC, Mar-M247 and so on, showed good agreement with those determined by chemical analysis. (author)

  16. Creep-Rupture Properties and Corrosion Behaviour of 21/4 Cr-1 Mo Steel and Hastelloy X-Alloys in Simulated HTGR Environment : Interim Report

    DEFF Research Database (Denmark)

    Lystrup, Aage; Rittenhouse, P. L.

    1977-01-01

    Hastelloy X and 2/sup 1///sub 4/ Cr-1 Mo steel are being considered as structural alloys for components of a High-Temperature Gas-Cooled Reactor (HTGR) system. Among other mechanical properties, the creep behavior of these materials in HTGR primary coolant helium must be established to form part of the design criteria. This report describes the simulated HTGR-helium environmental creep facilities, summarizes preliminary creep properties of 2/sup 1///sub 4/ Cr-1 Mo steel and Hastelloy X generated in HTGR helium and compares these with data obtained by testing in air. Some corrosion characteristics of the two materials are also discussed.

  17. Creep-rupture properties and corrosion behavior of 2 1/4 Cr-1 Mo steel and Hastelloy X alloys in simulated HTGR environment-interim report

    International Nuclear Information System (INIS)

    Hastelloy X and 21/4 Cr-1 Mo steel are being considered as structural alloys for components of a High-Temperature Gas-Cooled Reactor (HTGR) system. Among other mechanical properties, the creep behavior of these materials in HTGR primary coolant helium must be established to form part of the design criteria. This report describes the simulated HTGR-helium environmental creep facilities, summarizes preliminary creep properties of 21/4 Cr-1 Mo steel and Hastelloy X generated in HTGR helium and compares these with data obtained by testing in air. Some corrosion characteristics of the two materials are also discussed

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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.

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

    International Nuclear Information System (INIS)

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

  1. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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)

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

    International Nuclear Information System (INIS)

    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

  4. Hardening mechanisms in a dynamic strain aging alloy, Hastelloy X, during isothermal and thermomechanical cyclic deformation

    Science.gov (United States)

    Miner, R. V.; Castelli, M. G.

    1992-01-01

    The relative contributions of the hardening mechanisms in Hastelloy X during cyclic deformation were investigated by conducting isothermal cyclic deformation tests within a total strain range of +/-0.3 pct and at several temperatures and strain rates, and thermomechanical tests within several different temperature limits. The results of the TEM examinations and special constant structure tests showed that the precipitation on dislocations of Cr23C6 contributed to hardening, but only after sufficient time above 500 C. Solute drag alone produced very considerable cyclic hardening. Heat dislocation densities, peaking around 10 exp 11 per sq cm, were found to develop at temperatures producing the greatest cyclic hardening.

  5. Structure and mechanical properties of hot rolled bands of the KhN56VMTYu heat resisting alloy

    International Nuclear Information System (INIS)

    Effect is studied of the final rolling temperature and quenching conditions on the mechanical properties of KhN56VMTYu alloy obtained by vacuum-arc melting. The metal strength characteristics show a monotonous decrease with the rolling temperature growth, whereas plastisity increases, which is attributed to a more perfect realization of recrystallization processes. Lower plastisity at 1150 deg C is associated with a grain growth at high deformation temperatures. The highest plastisity increase and a simultaneous decrease in the strength take place in the case of water quenching. A quenching temperature of 1150 deg C ensures a reasonable standard plastisity of the metal, and the subsequent ageing provides the maximum heat-resistance behaviour

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

    International Nuclear Information System (INIS)

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

  7. Effect of electrical discharge machining process on crack susceptibility of nickel based heat resistant alloy

    Energy Technology Data Exchange (ETDEWEB)

    Kang, S.H.; Kim, D.E.

    2005-07-15

    The objective of this study was to investigate the effects of electrical discharge machining (EDM) process conditions on the crack susceptibility of a nickel-based superalloy. Because sequential processes are inevitable in the manufacturing industry, the effects of EDM and post-EDM processes on the crack propagation behaviour of the components need to be clearly understood. The altered material zone (AMZ) of EDM processed Hastelloy X revealed different morphology before and after solution heat treatment. Depending on the EDM dielectric fluid and the post-EDM process such as solution heat treatment, it was found that cracks existing in the recast layer could propagate into substrate when a 20% strain tensile force was applied at room temperature. In the case of the kerosene electrical discharge (ED) machined specimens, it was observed that carburisation and sharp crack propagation along the grain boundary occurred after the heat treatment. However, the deionised water ED machined specimens after heat treatment underwent oxidation and showed no crack propagation behaviour. A metallurgical evaluation of the microstructure of the AMZ was also conducted. (author)

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

    Science.gov (United States)

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

    1976-01-01

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

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Nagai, Hiroshi

    1987-11-25

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

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

    International Nuclear Information System (INIS)

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

  12. Effect of the fluency at Hf ion implantation on surface layer physicochemical state and mechanical properties of heat resistant Ti-alloys

    International Nuclear Information System (INIS)

    Effect of the fluency in the range 1016-2x1017 cm-2 at Hf ion implantation with energy 75 KeV on chemical composition, structure of surface layers, fatigue strength and dust erosion resistance of heat resistant Ti-alloys is investigated. It is shown for VT9-alloy that Hf ion implantation lead to increase fatigue strength on 80%, dust erosion resistance on 30%

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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 (?'+?). Carbide of the N3W3C type is crystallized from the liquid in interaxial spaces close to the eutectics (?'+?) as a result of the substitution of the elements forming ?'-phase: Ti, Nb and Hf for tungsten. Using the method of electric resistance temperature range of dissolving of highly disperse ?'-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 (?-?') 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 ?'-phase in ?-solid solution is 30 deg lower than Tsub(s)

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

    International Nuclear Information System (INIS)

    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.)

  17. Alloying effect on the structure and properties of austenitic heat-resistant steels

    International Nuclear Information System (INIS)

    Investigated have been mechanical properties at test temperatures of 20-95O deg C, wear resistance, softening at thermomechanical cycling and microstructure of cast austenitic chromium-nickel steels (13%Cr + 35%Ni), produced by electroslag remelting with variations in Ti, Mo, Nb and W contents. Regression equations for relationship of the investigated characteristics to alloying element content have been obtained. Titanium, molybdenum and niobium increasing hardness and strength limit at room and high temperatures promote a decrease in ductility. Tungsten increases strength properties, wear resistance and thermal stability of the steels without negative effect on the impact strength. The impact strength decrease with an increase in alloying is due to brittle precipitations along the boundaries of as-cast grains, containing Ti, Mo, Nb and Si

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

    Energy Technology Data Exchange (ETDEWEB)

    Sachova, E.; Hougardy, H.P.

    1988-10-01

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

  19. Strengtheninng of threaded connections of titanium and heat resistant chromium nickel alloys by thermovibrational treatment

    International Nuclear Information System (INIS)

    The paper presents results obtained by investigation of strengthening by thermovibrational treatment of threaded connections M6, M8 from alloy VT 16 and VT3-1 with a view to raise their creep resistance. Treatment conditions, empirical formulae are given to show how to determine the strengthening factor. Data on long strength of threaded connections in the initial state and after their treatment are given with data on weathering effect on strengthening preservation, certain mechanical and fatigue characteristics

  20. High temperature low-cycle fatigue and tensile properties of Hastelloy X and alloy 617 in air and HTGR-helium

    International Nuclear Information System (INIS)

    Results of strain controlled fatigue and tensile tests are presented for two nickel base solution hardened alloys which are reference structural alloys for use in several high temperature gas cooled reactor concepts. These alloys, Hastelloy X and Inconel 617, were tested at temperatures ranging from room temperature to 8170C in air and impure helium. Materials were tested in the solution annealed as well as in the pre-aged condition where aging consisted of isothermal exposure at one of several temperatures for periods of up to 20,000 h. Comparisons are also given between the strain controlled fatigue lives of these alloys and several other commonly used alloys all tested at 5380C. (Auth.)

  1. High-temperature low-cycle fatigue and tensile properties of Hastelloy X and alloy 617 in air and HTGR-helium

    International Nuclear Information System (INIS)

    Results of strain controlled fatigue and tensile tests are presented for two nickel base solution hardened alloys which are reference structural alloys for use in several high temperature gas cooled reactor concepts. These alloys, Hastelloy X Inconel 617, were tested at temperatures ranging from room temperature to 8710C in air and impure helium. Materials were tested in the solution annealed as well as in the pre-aged condition where aging consisted of isothermal exposure at one of several temperatures for periods of up to 20,000 h. Comparisons are also given between the strain controlled fatigue lives of these alloys and several other commonly used alloys all tested at 5380C

  2. Resistance of heat resisting steels and alloys to thermal and mechanical low-cycle fatigue

    International Nuclear Information System (INIS)

    Carried out is a comparative evalUation of resistance of different materials to thermocyclic deformation and fracture on the base of the experimental data on thermal and mechanical low-cycle fatigUe. Considered are peculiarities of thermal fatigue resistance depending on strength and ductility of the material. It is shown, that in the range of the cycle small numbers before the fracture preference is given to the high-ductility cyclically strengthening austenitic steels of 18Cr-10Ni type with slight relation of yield strength to the ?sub(0.2)/?sub(B) tensile strength Highly alloyed strength chromium-nickel steels, as well as cyclically destrengthening perlitic and ferritic steels with stronger ?sub(0.2)/?sub(B) relation as compared with simple austenitic steels turn to be more long-lived in the range of the cycle great numbers berore fracture. Perlitic steels are stated to have the lowest parameter values of the K crack growth intensity under the similar limiting conditions of the experiment, while steels and alloys with austenite structure-higher values of the K parameter

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

    International Nuclear Information System (INIS)

    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 potentialn and both, the critical pitting potentials and the pitting nucleation potentials, shift towards negative values. As third parameter the pH-value was varied. As expected, an increase of the pH-value extends the passive region to more negative values, the passive current density decreases. The variation of the pH-value does not affect the critical pitting potential. All tested alloys showed a clearly limited resistance against pitting corrosion phenomena. However, the best corrosion behaviour is shown by HASTELLOY C4, which has of all tested alloys the lowest passivation current density and the largest potential region with protection against local corrosion phenomena. (author)

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Wikstrom, N.P.; Egbewande, A.T. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada); Ojo, O.A. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, Winnipeg, Manitoba, R3T 5V6 (Canada)], E-mail: ojo@cc.umanitoba.ca

    2008-07-28

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

  6. Heat Treatment Development for a Rapidly Solidified Heat Resistant Cast Al-Si Alloy

    Science.gov (United States)

    Kasprzak, W.; Chen, D. L.; Shaha, S. K.

    2013-07-01

    Existing heat treatment standards do not properly define tempers for thin-walled castings that solidified with high solidification rates. Recently emerged casting processes such as vacuum high pressure die casting should not require long solution treatment times due to the fine microstructures arising from rapid solidification rates. The heat treatment studies involving rapidly solidified samples with secondary dendrite arm spacing between 10 and 35 ?m were conducted for solution times between 30 min and 9 h and temperatures of 510 and 525 °C and for various aging parameters. The metallurgical analysis revealed that an increase in microstructure refinement could enable a reduction of solution time up to 88%. Solution treatment resulted in the dissolution of Al2Cu and Al5Mg8Si6Cu2, while Fe- and TiZrV-based phases remained partially in the microstructure. The highest strength of approximately 351 ± 9.7 and 309 ± 3.4 MPa for the UTS and YS, respectively, was achieved for a 2-step solution treatment at 510 and 525 °C in the T6 peak aging conditions, i.e., 150 °C for 100 h. The T6 temper did not yield dimensionally stable microstructure since exceeding 250 °C during in-service operation could result in phase transformation corresponding to the over-aging reaction. The microstructure refinement had a statistically stronger effect on the alloy strength than the increase in solutionizing time. Additionally, thermal analysis and dilatometer results were presented to assess the dissolution of phases during solution treatment, aging kinetics as well as dimensional stability.

  7. Effect of ion implantation on inner oxidation and properties of a Ni-based heat-resistant alloy with protective coating

    International Nuclear Information System (INIS)

    A study is made into the effect of implantation of 100 keV Pt, Zr and Ti+Si ions with dose of 1017 cm-2 on structure, phase and chemical compositions and creep resistance of a heat resisting nickel base ZhS6U alloy. It is found that ion implantation fails to prevent internal oxidation of the alloy under protective Ni-Cr-Al-Y coating in the processes of high temperature annealing at 1273 K and creep at the air and in vacuum

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

    International Nuclear Information System (INIS)

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

  9. Internal stress during high-temperature creep and activation energy for creep of Hastelloy XR

    International Nuclear Information System (INIS)

    Creep tests and measurements of internal stress during creep and activation energy for creep were performed at 900 deg C for Hastelloy XR and XR-II developed as heat resistant alloys for high temperature gas cooled reactors. Creep rupture time and steady-state creep rate were influenced by the parameters of boron content, grain size and heat treatment temperature of the alloys. Although the internal stress during creep was also dependent on these parameters, the activation energy for creep was independent on them. It is shown that dependence of the steady-state creep rate on the parameters corresponds to the change in the internal stress. The fact shows the concept of the internal stress is effective to describe steady-state creep behavior of the alloys. (author)

  10. Comparison of laser, electron beam and argon arc welding of heat resisting KhN68VMTYuK nickel alloy

    International Nuclear Information System (INIS)

    Comparison of the effect of laser, electron beam and argon arc welding (LW, EBW, AAW) on weld geometry, effectiveness of penetration and welded joint properties has been made. It has been shown that an aplication of laser welding for heat resisting KhN68VMTYuK alloy 1.5 m thick under rigid conditions conduces to a formation of high quality metal weld. This type of welding increases the process effectiveness, resistance to hot cracking and mechanical properties as compared to AAW and LW at small rates. It is inferior to EBW in all technological properties

  11. Modulation Effects of K2ZrF6 Additive on Microstructure and Heat Resistance of Micro-arc Oxide Coatings Fabricated on LY12 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    ZHANG Xin-Meng, CHEN Dong-Fang, GONG Chun-Zhi , YANG Shi-Qin, TIAN Xiu-Bo

    2010-07-01

    Full Text Available Zr(OH4 particle can be formed and negatively charged in alkaline solution with K2ZrF6 addition. Based on this mechanism, Zr-containing ceramic coatings were fabricated on LY12 aluminum alloy by microarc oxidation (MAO using K2ZrF6 as a special additive in Na2SiO3-KOH base electrolyte. The modulation effects of K2ZrF6 addition on micro-microstructure, element distribution and phase composition were analyzed by SEM, EDS and XRD, respectively. Heat resistance of MAO coatings formed on LY12 aluminum alloy in different electrolyte was investigated. The results show that the K2ZrF6 addition can increase the micro-arc oxidation rate and significantly alter the structure of MAO coatings. Both the top surface and inner surface of MAO coatings fabricated in Zr-containing electrolyte become relatively smooth. Compared with the coating formed in Zr-free electrolyte, a large amount of Zr element is found in the coating formed in electrolyte with K2ZrF6 addition. Two main phases, ?-Al2O3 and ?-Al2O3, are contained in Zr-free coating. In contrast, more amorphous phase is found in Zr-containing coating with reduced amount of crystalline alumina. Experimental results also demonstrate that Zr-containing coating exhibits higher heat resistance.

  12. Characteristics and experimental evaluation of super-heat-resisting Nb-based and Mo-based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Morinaga, Masahiko; Furui, Mitsuaki; Noda, Kenji; Oda, Masaaki [Nagoya Univ. (Japan). School of Engineering

    1997-03-01

    Nb-based and Mo-based alloys have been investigated in order to develop the frontiers of materials technique which will be utilized in the environment of high-temperature liquid alkali metals. In this study, both mechanical properties and corrosion resistance to liquid Li were evaluated for two designed Mo-based alloys, Mo-15Re-0.1Zr and Mo-15Re-0.1Zr-0.1Ti. In addition, a series of corrosion test was performed with provisionally designed Nb-based alloys, Nb-(1-4)Hf. High-temperature tensile properties: The designed Mo-based alloys were found to have more excellent high-temperature tensile properties, compared to the commercial TZM alloy. High-temperature creep properties: The designed Mo-based alloys were superior in the high-temperature creep properties to other solid solution hardening Mo-based alloys. Workability: The designed Mo-based alloys exhibited an excellent workability, irrespective of the Ti addition. Corrosion resistance to liquid Li: The Nb-1Hf alloy was chosen as a promising alloy of having the highest corrosion resistance among the Nb-based alloys. Also, the Mo-15Re-0.1Zr-0.1Ti alloy was superior to Mo-15Re-0.1Zr alloy, in view of the corrosion resistance to liquid Li. (J.P.N.)

  13. Optimization of the structure and composition of heat resisting alloys on the basis of Al-Cu-Mn-Zr-Cr system

    International Nuclear Information System (INIS)

    The effects of composition and manufacturing technique on structure, low-temperature mechanical properties and heat resistance of the Al-Cu-Mn-Zr-Cr system as ingots and hot-rolled sheets are studied. It is established that in billets of 20 x 40 x 180 mm in size the solubility of zirconium and chromium in aluminium-copper solid solution can achieve 0.8% (mass) under the certain conditions. As a promising composition the composition Al-2.5% Cu-1% Mn-0.4% Zr-0.4% Cr is proposed which in form of hot-rolled sheets exceeds D 20 type alloy in low-temperature mechanical properties and high-temperature strength index at 400 deg C

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-11-05

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

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

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

    International Nuclear Information System (INIS)

    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.)

  18. Structure and properties of fiber composite material-heat resisting nickel base alloy reinforced with tungsten fibers

    International Nuclear Information System (INIS)

    The results are presented of an investigation into the properties of a fibrous ocmposition material (FCM) nickel alloy EP-202-tungsten-rhenium wire obtained by explosion pressing. To evaluate the structural stability of FCM, the effect is studied of vacuum annealing in the temperature range of 800-1200 deg C on interaction of the fibre with the matrix and the composition is established of the segregating phase with the aid of microroentgenospectral analysis

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1988-10-01

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

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

    International Nuclear Information System (INIS)

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

  1. Influence of Hot-Working Conditions on High-Temperature Properties of a Heat-Resistant Alloy

    Science.gov (United States)

    Ewing, John F; Freeman, J W

    1957-01-01

    The relationships between conditions of hot-working and properties at high temperatures and the influence of the hot-working on response to heat treatment were investigated for an alloy containing nominally 20 percent molybdenum, 2 percent tungsten, and 1 percent columbium. Commercially produced bar stock was solution-treated at 2,200 degrees F. to minimize prior-history effects and then rolled at temperatures of 2,200 degrees, 2,100 degrees, 2,000 degrees, 1,800 degrees, and 1,600 degrees F. Working was carried out at constant temperature and with incremental decreases in temperature simulating a falling temperature during hot-working. In addition, a few special repeated cyclic conditions involving a small reduction at high temperature followed by a small reduction at a low temperature were used to study the possibility of inducing very low strengths by the extensive precipitation accompanying such properties. Most of the rolling was done in open passes with a few check tests being made with closed passes. Heat treatments at both 2,050 degrees and 2,200 degrees F. subsequent to working were used to study the influence on response to heat treatment.

  2. Hafnium-silicon precipitate structure determination in a new heat-resistant ferritic alloy by precession electron diffraction techniques.

    Science.gov (United States)

    Viladot, Désirée; Portillo, Joaquim; Gemí, Mauro; Nicolopoulos, Stavros; Llorca-Isern, Núria

    2014-02-01

    The structure determination of an HfSi4 precipitate has been carried out by a combination of two precession electron diffraction techniques: high precession angle, 2.2°, single pattern collection at eight different zone axes and low precession angle, 0.5°, serial collection of patterns obtained by increasing tilts of 1°. A three-dimensional reconstruction of the associated reciprocal space shows an orthorhombic unit cell with parameters a = 11.4 Å, b = 11.8 Å, c = 14.6 Å, and an extinction condition of (hkl) h + k odd. The merged intensities from the high angle precession patterns have been symmetry tested for possible space groups (SG) fulfilling this condition and a best symmetrization residual found at 18% for SG 65 Cmmm. Use of the SIR2011 direct methods program allowed solving the structure with a structure residual of 18%. The precipitate objects of this study were reproducibly found in a newly implemented alloy, designed according to molecular orbital theory. PMID:24172206

  3. Corrosion and stress corrosion cracking characteristics of nickel base alloys, titanium and zirconium in gas scrubber conditions. Pt. 1. Final report. [Inconel 625; Hastelloy B; Hastelloy C 4; Hastelloy C 22; Hastelloy C 276; Ti; Zr]. Untersuchungen zum Korrosions- und SpRK-Verhalten von Nickelbasislegierungen, Titan und Zirkonium unter in Gaswaschanlagen herrschenden Bedingungen. T. 1. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Steffens, H.D.

    1990-06-26

    The reaearch project had the objective to investigate the corrosion behavior of nickel basic alloys, titanum and zirconium in highly loaded waters with the components NH[sub 3], H[sub 2]S, CO[sub 2], CN[sup -] and Cl[sup -]. The limits of application of the materials in dependence on the composition and temperature of the medium are to be determined. For this, degradation measurements, SpRK tests under static load and investigations on hybrid embrittlement have been made. (orig.).

  4. 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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  5. Corrosion of nickel alloys in nuclear fuel reprocessing

    International Nuclear Information System (INIS)

    Corrosion studies were made of high Ni alloys in process solutions which will be encountered during reprocessing of fuel from Shippingport PWR Core 2, seeds 1 and 2. The alloys were Hastelloy C-276 and C-4, Inconel 625, Incoloy 825, Hastelloy S, Hastelloy G, and Inconel 671. Effects of process variables were studied. Welded Hastelloy C-276 vessels were constructed and tested. (DLC)

  6. Precipitation studies in hastelloy C-276

    International Nuclear Information System (INIS)

    Commercially available Hastelloy C-276 has been examined for precipitation behavior and mechanical properties. The alloy has been aged at 650 and 850 C for 1-240 hrs time intervals. Hardness has been measured as a function of ageing time. Hardness increases with time at higher ageing temperature while it remains constant at lower temperature. Electron microscope examination revels Mo rich precipitates at 850 C and their density being increase with time. Preliminary results on the fracture toughness shows that the materials fails mainly through brittle mode. (author)

  7. Long-term corrosion behaviors of Hastelloy-N and Hastelloy-B3 in moisture-containing molten FLiNaK salt environments

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Fan-Yi, E-mail: fyouyang@ess.nthu.edu.tw; Chang, Chi-Hung; Kai, Ji-Jung

    2014-03-15

    Highlights: •Corrosion behaviors of Hastelloy-N and -B3 in molten FLiNaK salt at 700 °C. •The alleviated corrosion rate of alloys was observed after long-hour immersion. •Long-term corrosion rate was limited by diffusion from matrix to alloy surface. •Corrosion pattern transferred from intergranular corrosion into general corrosion. •Presence of minor H{sub 2}O did not greatly influence the long-term corrosion behavior. -- Abstract: This study investigated long-term corrosion behaviors of Ni-based Hastelloy-N and Hastelloy-B3 under moisture-containing molten alkali fluoride salt (LiF–NaF–KF: 46.5–11.5–42%) environment at an ambient temperature of 700 °C. The Hastelloy-N and Hastelloy-B3 experienced similar weight losses for tested duration of 100–1000 h, which was caused by aggregate dissolution of Cr and Mo into FLiNaK salts. The corrosion rate of both alloys was high initially, but then reduced during the course of the test. The alleviated corrosion rate was due to the depletion of Cr and Mo near surface of the alloys and thus the long-term corrosion rate was controlled by diffusion of Cr and Mo outward to the alloy surface. The results of microstructural characterization revealed that the corrosion pattern for both alloys tended to be intergranular corrosion at early stage of corrosion test, and then transferred to general corrosion for longer immersion hours.

  8. Long-term corrosion behaviors of Hastelloy-N and Hastelloy-B3 in moisture-containing molten FLiNaK salt environments

    International Nuclear Information System (INIS)

    Highlights: •Corrosion behaviors of Hastelloy-N and -B3 in molten FLiNaK salt at 700 °C. •The alleviated corrosion rate of alloys was observed after long-hour immersion. •Long-term corrosion rate was limited by diffusion from matrix to alloy surface. •Corrosion pattern transferred from intergranular corrosion into general corrosion. •Presence of minor H2O did not greatly influence the long-term corrosion behavior. -- Abstract: This study investigated long-term corrosion behaviors of Ni-based Hastelloy-N and Hastelloy-B3 under moisture-containing molten alkali fluoride salt (LiF–NaF–KF: 46.5–11.5–42%) environment at an ambient temperature of 700 °C. The Hastelloy-N and Hastelloy-B3 experienced similar weight losses for tested duration of 100–1000 h, which was caused by aggregate dissolution of Cr and Mo into FLiNaK salts. The corrosion rate of both alloys was high initially, but then reduced during the course of the test. The alleviated corrosion rate was due to the depletion of Cr and Mo near surface of the alloys and thus the long-term corrosion rate was controlled by diffusion of Cr and Mo outward to the alloy surface. The results of microstructural characterization revealed that the corrosion pattern for both alloys tended to be intergranular corrosion at early stage of corrosion test, and then transferred to general corrosion for longer immersion hours

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.)

  11. 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

    CERN Document Server

    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

  12. Prediction of regularities in changes of properties of nickel-base heat resistance alloys in dependence on chromium, cobalt, niobium and tungsten contents

    International Nuclear Information System (INIS)

    Dependence of specific electric resistance of Ni-Al-Ti-Nb-Cr-Co-W system alloys on temperature and content of alloying elements is studied to obtain calculation ratios permitting to predict the dependence of physical properties on the chemical composition. It is shown, that the alloy has the maximum value of electric resistance at maximum Cr, W, Nb contents and at minimum Co content. Character of temperature dependence is connected mainly with processes on the boundaries of ?- and ?'-phases. Experimental data are presented in the form of mathematical dependences

  13. Structure and electrical properties of heat resistant bimetallic conductors

    International Nuclear Information System (INIS)

    The interaction between constituents of heat resistant bimetallic electric conductors in the range of 20-1000 deg C and its influence on the properties of materials were investigated. Bimetallic specimens were prepared by hot forging and rolling. The core was made of copper. The outer layers consisted of stainless steel 12Kh18N9T or heat resistant alloy Kh23Yu5T. The results of microscopic examination and electric conductivity measurements showed that the bimetallic conductor with an outer layer of the heat resistant alloy can successfully operate at high temperatures and preserve stable electric characteristics much better than any of other available materials. 14 refs.; 4 refs.; 2 tabs

  14. Effect of low-temperature thermomechanical treatment on the heat resistance of low alloys of the Mo-Zr-C and Mo-Zr-Nb-C systems

    International Nuclear Information System (INIS)

    Investigated was the low-temperature thermomechanical treatment (hardening from 2100 deg C, hydraulic extrusion with a reduction of 40% + ageing at 1200 deg C) upon the long-term strength at 1100 and 1300 deg C of molybdenum alloys with additions of zirconium and niobium. It was found, that the treatment enhances the long-term strength of alloys of the Mo-Zn-C and Mo-Zr-Nb-C systems at the test temperature of 1100 deg C 1.7-2 times as compared to hardening and ageing. At 1300 deg C, the considerable increment of the long-term strength is observed only during short test. The addition of 0.2 weight % Nb raises the long-term strength of the Mo-Zr-C alloys

  15. PARALLOYS SH24T and SH39T - A new generation of heat resisting alloys - Synergistically strengthened with titanium, columbium, and zirconium

    International Nuclear Information System (INIS)

    A new generation of high temperature petrochemical alloys has been developed by APV Paramount Ltd. which offer increased creep strength due to synergistic hardening additions of titanium, columbium and zirconium. Work done at Cambridge University on the strengthening mechanisms is also described

  16. 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

    International Nuclear Information System (INIS)

    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 ?=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 ?m (TiSiB), 0.4 ?m (NiCrAlY), and 1 ?m (Zr N) during a pulse under the optimal conditions of HPPIB irradiation

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

    International Nuclear Information System (INIS)

    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

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

    Scientific Electronic Library Online (English)

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

    2014-04-01

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

  19. High-temperature stress rupture performance of Hastelloy C-276

    International Nuclear Information System (INIS)

    Hastelloy C-276 is one of the candidate cladding materials in supercritical water cooling reactor (SWCR). In this study, the SEM and TEM were used to investigate the microstructure of C-276 alloy before and after ruptured at 650 ? under different tensile stresses. Based on the experimental results, it can be concluded that the C-276 alloy has a good high-temperature stress rupture performance which is speculated to be the co-effects of solid solution-strengthening, precipitation-strengthening and deformation twin-strengthening. (author)

  20. Composition of eta carbide in Hastelloy N after aging 10,000 hr at 8150C

    International Nuclear Information System (INIS)

    The composition of the eta carbide in Hastelloy N containing 0.7 wt percent Si in the alloy approaches M12C, rather than M6C as indicated in the alloy literature. The silicon content of the eta phase in this case was about 25 at. percent, much higher than has been observed in less highly alloyed material. The data do not permit a definition of the limiting compositions of the phases

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

    International Nuclear Information System (INIS)

    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

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

    DEFF Research Database (Denmark)

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

    1976-01-01

    Hastelloy X, an Ni--Cr--Fe--Mo alloy, may be an important structural alloy for components of gas-cooled reactor systems. Expected applications of this alloy in the High-Temperature Gas-Cooled Reactor (HTGR) are discussed, and the development of interim mechanical properties and supporting data are 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.

  3. Crack propagation in Hastelloy X

    International Nuclear Information System (INIS)

    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

  4. Creep properties of heat-resistant superalloys for nuclear plants in helium

    International Nuclear Information System (INIS)

    In order to estimate the creep and rupture strengths of candidate alloys for the intermediate heat exchanger of VHTR, creep and stress rupture tests in impure helium were conducted on Hastelloy X, Inconel 617, Inconel 625, Incoloy 800 and Incoloy 807 at 9000C. The results were discussed in comparison with those in air and the alloys were examined from the point of view of the elevated temperature structural design. The main results obtained are summarized as follows: (1) No appreciable decrease in creep and rupture strengths in helium as compared with those in air is observed on Hastelloy X and Inconel 625. On the contrary, the creep and rupture strengths of Inconel 617 in helium decrease slightly as compared with those in air. In the case of Incoloy 807, the creep strength to cause 1 percent total strain and that to initiate secondary creep increase remarkably in helium as compared with those in air. However, the creep strength to cause initiation of tertiary creep and the rupture strength in helium remarkably decrease as compared with those in air. (2) The order of magnitude of the S0 value for each material in helium is as follows; Hastelloy X > Inconel 617 > Incoloy 807 > Inconel 625 > Incoloy 800 Meanwhile, that of the S sub(t) value in helium is; Inconel 617 > Hastelloy X > Incoloy 807 > Inconel 625 > Incoloy 800. (author)

  5. 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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-10-15

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Alloys For Flexible Hoses In A Corrosive Environment

    Science.gov (United States)

    Macdowell, Louis G., III; Ontiveros, Cordelia

    1992-01-01

    High-nickel alloy resists pitting corrosion. Report evaluates metal alloys for flexible hoses in corrosive environment. Tested to find alternatives to 304L stainless steel. Nineteen alloys selected for testing on basis of reputation for resistance to corrosion. Top five, in order of decreasing resistance to corrosion: Hastelloy(R) C-22, Inconel(R) 625, Hastelloy(R) C-276, Hastelloy(R) C-4, and Inco(R) alloy G-3. Of these, Hastelloy(R) C-22 found best for flexible-hose application.

  8. Hydrogen permeation through heat transfer pipes made of Hastelloy XR during the initial 950 °C operation of the HTTR

    Science.gov (United States)

    Sakaba, Nariaki; Ohashi, Hirofumi; Takeda, Tetsuaki

    2006-07-01

    The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat transfer pipes of the intermediate heat exchanger in the HTTR, is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. The hydrogen permeation between the primary and secondary coolants through the Hastelloy XR was evaluated using the actual hydrogen concentrations observed during the initial 950 °C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E0 and pre-exponential factor F0 of the permeability of hydrogen were E0 = 65.8 kJ/mol and F0 = 7.8 × 10 -9 m 3(STP)/(m s Pa 0.5), respectively, in the temperature range from 707 to 900 K.

  9. Hydrogen permeation through heat transfer pipes made of Hastelloy XR during the initial 950 deg. C operation of the HTTR

    Energy Technology Data Exchange (ETDEWEB)

    Sakaba, Nariaki [HTGR Cogeneration Design and Assessment Group, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA), Oarai, Higashiibaraki, Ibaraki 311-1393 (Japan)]. E-mail: sakaba.nariaki@jaea.go.jp; Ohashi, Hirofumi [HTGR Cogeneration Design and Assessment Group, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA), Oarai, Higashiibaraki, Ibaraki 311-1393 (Japan); Takeda, Tetsuaki [HTGR Performance and Safety Demonstration Group, Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency (JAEA), Oarai, Higashiibaraki, Ibaraki 311-1393 (Japan)

    2006-07-01

    The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat transfer pipes of the intermediate heat exchanger in the HTTR, is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. The hydrogen permeation between the primary and secondary coolants through the Hastelloy XR was evaluated using the actual hydrogen concentrations observed during the initial 950 deg. C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E {sub 0} and pre-exponential factor F {sub 0} of the permeability of hydrogen were E {sub 0} = 65.8 kJ/mol and F {sub 0} = 7.8 x 10{sup -9} m{sup 3}(STP)/(m s Pa{sup 0.5}), respectively, in the temperature range from 707 to 900 K.

  10. Hydrogen permeation through heat transfer pipes made of Hastelloy XR during the initial 950 deg. C operation of the HTTR

    International Nuclear Information System (INIS)

    The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat transfer pipes of the intermediate heat exchanger in the HTTR, is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. The hydrogen permeation between the primary and secondary coolants through the Hastelloy XR was evaluated using the actual hydrogen concentrations observed during the initial 950 deg. C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E 0 and pre-exponential factor F 0 of the permeability of hydrogen were E 0 = 65.8 kJ/mol and F 0 = 7.8 x 10-9 m3(STP)/(m s Pa0.5), respectively, in the temperature range from 707 to 900 K

  11. Creep of some heat resistant steels

    International Nuclear Information System (INIS)

    The creep behaviour of important heat resistant steels is examined to establish creep equations. For two well tested materials (10 CrMo 9 10, X 22 CrMoV 12 1), equations are proposed, which are valid in the whole range of temperature, stress and time. (orig./MM)

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

    International Nuclear Information System (INIS)

    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

  13. Fatigue and uniaxial deformation behavior of Hastelloy XR at elevated temperatures

    International Nuclear Information System (INIS)

    Fully reversed continuous cycling tests and tensile tests were conducted on Hastelloy XR at temperatures ranging from 600 deg C to 950 deg C in air. Fatigue life of Hastelloy XR depends on temperature. A series of SEM observation revealed that transgranular fracture with evident striation formation was dominant at temperatures below 800 deg C, while intergranular cracking was found above 900 deg C. These results suggest that creep mechanism takes place in the fatigue behavior of this alloy above 900 deg C. Numerical analyses of deformation behavior during fatigue and tensile tests were conducted to interpret the experimental results. Conventional elastic-creep constitutive equation gave a good prediction of this deformation process. (author)

  14. Creep properties of 20% cold worked hastelloy XR

    International Nuclear Information System (INIS)

    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, ?m, 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, ?m 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. Application of newly developed heat resistant materials for USC boilers

    International Nuclear Information System (INIS)

    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.)

  16. On the estimation of long term creep rupture strength of Hastelloy XR in HTGR helium environment

    International Nuclear Information System (INIS)

    Using special type specimens, which contained multiple diameters with step within the gauge portion in one piece, creep rupture and the associated surface phenomena were examined with special emphasis placed on the effect of oxidation and carburization on the creep and rupture properties. Based on the results obtained, creep rupture strength of alloy XR at 800 to 10000C under the influence of impure helium environment has been critically discussed. Oxidation kinetics of the alloy in the helium environment was not seen to be accelerated by the in creep deformation appreciably within the range of conditions tested. The duplex-structure oxide film formed on Hastelloy alloy XR, being composed of MnCr2O4 spinel type oxide and Cr2O3, maintained its function up to the creep strain of a few per cent, and the degree of carburization occurred during the steady creep stage was not affected by the deformation. After the onset of accelerating creep and the resultant initiation of the surface cracks, however, the continuity of the oxide film was lost to cause severe carburization. Parallel to those tests, the same material was pack-carburized up to the carbon content of about 0.4 wt%. The treatment caused decrease in both rupture elongation and strength. Based on the observed facts, a concept of conservatism to be included in the predictive evaluation was proposed in the estimation of the long term creep rupture strength of Hastelloy alloy XR in the HTGR impure helium environment. It is concluded that the 50% value of the rupture life in inert environment is the presently most conservative rupture life of Hastelloy alloy XR in HTGR helium environment. (author)

  17. Heat resistance of juice spoilage microorganisms.

    Science.gov (United States)

    Shearer, Adrienne E H; Mazzotta, Alejandro S; Chuyate, Rolenda; Gombas, David E

    2002-08-01

    The heat resistance of various yeasts (Saccharomyces cerevisiae, Rhodotorula mucilaginosa, Torulaspora delbrueckii, and Zygosaccharomyces rouxii), molds (Penicillium citrinum, Penicillium roquefortii, and Aspergillus niger), and lactic acid bacteria (Lactobacillus fermentum and Lactobacillus plantarum) obtained from spoiled acid or acidified food products was determined in 0.1 M citrate buffer at pH values of 3.0, 3.5, and 4.0. S. cerevisiae was the most heat resistant of the microorganisms in citrate buffer, and its heat resistance was further evaluated in apple, grapefruit, calcium-fortified apple, and tomato juices as well as in a juice base with high fructose corn syrup. Decimal reduction times (D-values) and changes in temperature required to change the D-value (z-values) for S. cerevisiae were higher in the juices than in citrate buffer at all pH values tested. The D57 degrees C(135 degrees F)-values varied from 9.4 min in the juice product with pH 2.8 to 32 min in a calcium-added apple juice with pH 3.9. The S. cerevisiae strain used in this study can be used in thermal-death-time experiments in acidic products to calculate process conditions and in challenge tests to validate the calculated temperatures and hold times during processing. PMID:12182479

  18. CORN CULTIVAR IDENTIFICATION THROUGH HEAT RESISTANT PROTEINS

    Directory of Open Access Journals (Sweden)

    SOLANGE CARVALHO BARRIOS ROVERI JOSÉ

    2004-04-01

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

  19. Resistance to isothermal and non-isothermal low cycle loading in heat resisting materials

    International Nuclear Information System (INIS)

    An equation for preliminary estimation of the material durability at thermal fatigue taking into account a decrease of strength and ductility with time under loading is suggested. The calculated curves are compared with the experimental ones for a number of heat resisting nickel alloys (EhI437B, ZhS6K and others). A good correspondence of the results for the cases of loading without holding at the maximum temperature is obtained

  20. Heat resistant fast neutron shielding material

    International Nuclear Information System (INIS)

    A heat resistant binder comprising a metal hydride powder and calcium silicate is dispersed finely, to provide a structure having a porosity of less than 45%. It contains to 50 to 800 parts by weight of metal hydride based on 100 parts by weight of calcium silicate, in which the calcium silicate has a CaO/SiO2 molar ratio of silicic acid and lime materials within a range of 0.5 to 2.0. The metal hydride comprises one of metals of Ti, Zr, Y and Gd having hydrogen/metal atom ratio within a range of greater than 0.7. Oxide coating layers are formed on the surface of the fine powder of the metal hydride, thereby enabling to suppress the release of hydrogen gases caused by dissociation. Since the heat resistant binder is stable up to a high temperature of about 700degC, and excellent in moldability, it has mechanical strength and thermal stability such as dimensional stability for the molding products. (T.M.)

  1. Improved Ni--Cr--Mo alloy for corrosion service

    International Nuclear Information System (INIS)

    A new Ni-Cr-Mo corrosion resistant alloy, Hastelloy alloy C-4, has been developed that does not precipitate an intermetallic Mu phase upon aging in the 650 to 10900C temperature range. This further improvement of Hastelloy alloy C-276 has evolved from a detailed study of the effects of the substitutional and interstitial elements on the precipitation of intermetallic and carbide phases. Data have been generated to show that Hastelloy alloy C-4 is basically equivalent in corrosion resistance to its predecessors in both oxidizing and reducing media

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

    International Nuclear Information System (INIS)

    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

  3. Effects of gaseous environments in gas-cooled reactors and solar thermal heat exchangers on the creep and creep-rupture properties of heat-resisting metals and alloys. Final report

    International Nuclear Information System (INIS)

    Energy conversion systems employing heat exchangers use closed cycle gas turbines with helium as the working fluid. An important design criterion for heat exchanger and turbine systems is the creep strength of the tubing, blading, and vane materials. The design data for these materials generally has been obtained in air. However, there have been reports of adverse environmental effects of helium on the creep strength and ductility of these materials. Much of the environmental data has been obtained using relatively impure helium from high temperature helium-cooled reactor systems (HTGR's). However, power conversion systems using coal or solar energy as the heat source would use commercially pure helium, not subject to the carbonaceous gases that are picked up when helium is used as the coolant for the HTGR's. Stanford University was asked to summarize the environmental effects of helium on the creep properties of heat exchanger alloys. Also, they were asked to conduct critical experiments under what ought to probably be the worst conditions, based on the literature, to determine the maximum extent of the environmental effect. It was found that the environmental effects reported in the literature are relatively small, not more than a factor of two in rupture time or creep rate, which is within the usual experimental scatter and in heat-to-heat variations. The experimental work reported on a HA188 confirmed this conclusion

  4. Heat resistant concrete (Rhine sand concrete)

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    P. Baranowski

    2009-04-01

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

  6. Fundamental studies on electron beam welding of heat-resistant superalloy for nuclear plants, (2)

    International Nuclear Information System (INIS)

    In the previous report, it was described that the defects occurred in electron beam welds were porosity and microcracks which ran approximately perpendicular to the fusion lines and were found much in the nailhead area. In this report, the consideration and investigation have been carried out on the mechanism of weld crack generation. As the metallurgical studies, observation of the structure of heat-affected zones adjacent to the fusion lines of electron beam welds with a scanning electron microscope, composition analysis of the precipitates with an X-ray microanalyzer and identification of the precipitates by X-ray diffraction have been carried out, using Hastelloy-group, Inconel-group and Incoloy-group heat-resistant superalloys for nuclear plants, and austenitic stainless steel for comparison. Further, the temperature, stress and strain distribution in heat-affected zone adjacent to the fusion line of a model has been analyzed, which has been provided to simulate the conditions in the processes of electron beam welding. As a result, it has been clarified that such microcracks were mainly caused by both melting of precipitates in the heat-affected zone adjacent to the fusion line, and the behaviors of temperature, stress and strain distributions in the nailhead area peculiar to electron beam welding. (Wakatsuki, Y.)

  7. TEM investigation on the microstructural evolution of Hastelloy N induced by Ar? ion irradiation.

    Science.gov (United States)

    Liu, Min; Lu, Yanling; Liu, Renduo; Zhou, Xingtai

    2014-02-01

    Hastelloy N alloy has been selected as the primary structure material for molten salt reactor. In this article, Hastelloy N alloy samples were irradiated to different doses at room temperature using 300 keV Ar(+) ions. The microstructural evolution was investigated by transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS). Black dot defects emerged in sample irradiated at low dose (0.4 displacement per atom (dpa)), and they grew up with irradiation doses (0.4-2 dpa). A high density of small dislocation loops (nano meters in size) were observed in the sample irradiated to 4 dpa. When the ion dose increased to 12 dpa, complicated structures with defects (including dislocation lines, larger loops and smaller black dots) were observed. Dislocation networks were detected from high-angle annular dark field (HAADF) images. Larger dislocation loops (size: 30-80 nm) were visible in the sample irradiated to 40 dpa. Irradiation with dose of 120 dpa led to the formation of face-centered cubic nanocrystallites with preferred orientations. PMID:24285574

  8. Development of Heat-resistant XLPE Cable and Accessories

    Science.gov (United States)

    Yamada, Hiroyuki; Nakagawa, Shinichi; Murata, Yoshinao; Kishi, Kouji; Katakai, Shoshi

    We have developed heat-resistant XLPE cable and accessories that can be operated at 105°C as the maximum permissible conductor temperature in normal operation. Through this cable system, greater transmission capacity can be achieved using existing cable ducts and without increasing the conductor size of the cable. We have developed heat-resistant XLPE insulation material which has a higher melting point than that of conventional XLPE. The breakdown strength of heat-resistant XLPE cable at 105°C is almost the same as that of conventional XLPE cable at 90°C. The heat deformation of the new cable at 105°C is almost the same as that of conventional XLPE cable at 90°C. Conventional self-pressurized rubber joints can be applied to heat-resistant cable lines with the new waterproof joint compound with low heat resistivity.

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

    International Nuclear Information System (INIS)

    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)

  10. Electrochemical impedance spectrometry using 316L steel, hastelloy, maraging, Inconel 600, Elgiloy, carbon steel, TiN and NiCr. Simulation in tritiated water. 2 volumes; Spectrometrie d`impedance electrochimique sur acier 316L, hastelloy, maraging inconel 600, elgiloy, acier au carbone, TiN, NiCr. Simulations en eau tritiee. 2 volumes

    Energy Technology Data Exchange (ETDEWEB)

    Bellanger, G.

    1994-03-01

    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.

  11. Microstructure and hardness studies of the electron beam welded zone of Hastelloy C-276

    International Nuclear Information System (INIS)

    Electron beam welding (EBW) technique is becoming popular in nuclear, chemical and aerospace industries due to its high penetration depth and fast cooling rate. Samples of Hastelloy C-276 have been welded by electron beam (EB). A scanning electron microscope (SEM) having the attachment of an energy dispersive system (EDS) has been employed to study the resulting microstructure and micro-eutectic phases. The microstructure of the molten zone (MZ) is found to be of fine lamellar type. The hardness of the MZ is found to be 35% higher compared to as-received alloy. The micro-eutectoids are rich in Mo and W. The X-ray diffraction patterns of the MZ show shifting of peaks towards higher angle compared to the diffraction pattern of the as-received alloy. Broadening of the peaks is also observed in the diffraction pattern of the MZ. Formation of the ?-phase was observed in the MZ after a tempering treatment at 950 deg. C

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

    International Nuclear Information System (INIS)

    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, ?m, 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, ?m 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)

  13. Creep properties of EB welded joint on Hastelloy X

    International Nuclear Information System (INIS)

    In order to clarify the creep properties of EB welds on Hastelloy X which is one of the candidate alloys for components of VHTR, creep tests on EB weld metal and welded joint were carried out. The results were discussed in comparison with those of base metal and TIG welds. Further, EB welds were evaluated from the standpoint of high temperature structural design. The results obtained are summarized as follows. 1) Both creep rupture strengths of EB weld metal and EB welded joint are almost equal to that of base metal, but those of TIG welds are lower than base metal. As for the secondary creep rate, EB weld metal is higher and TIG weld metal is lower than base metal. As for the time to onset of tertiary creep, no remarkable difference among base metal, EB weld metal and TIG weld metal is observed. 2) In case of EB weld metal, although anisotropy is slightly observed, the ductility is same or more as compared with base metal. In case of TIG weld metal, on the contrary, anisotropy is not observed and the ductility is essentially low. 3) Such rupture morphology of EB weld metal as appears to have resulted from interconnection of voids which occurred at grain boundary is similar to base metal. In case of TIG weld metal, however, many cracks with sharp tips are observed at grain boundary, and the rupture appears to have occurred in brittle by propagation and connection of the cracks. 4) It can be said from the standpoint of high temperature structural design that EB weldingperature structural design that EB welding is very suitable to welding for structure where creep effects are significant, because both of the creep ductility and the rupture strength are almost equal to those of base metal. (author)

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

    OpenAIRE

    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...

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

    International Nuclear Information System (INIS)

    12% Cr heat resistant steels with a fine dispersion of nano precipitates were designed supported by thermodynamic modeling. A detailed characterization of the microstructure evolution at different creep times (100 MPa/650 deg. C/8000 h) was carried out by scanning transmission electron microscopy (STEM). The results of the microstructure analysis are correlated with the mechanical properties in order to investigate the influence of different precipitates (especially M23C6) on the creep strength of the alloys. Precipitation of Laves phase and Z-phase was observed after several hours creep time. Very few Z-phase of the type Cr(V,Ta)N nucleating from existing (V,Ta)(C,N) was observed. Both alloys show growth and coarsening of Laves phase, meanwhile the MX carbonitrides present a very slow growth and coarsening rate. Alloys containing Laves phase, MX and M23C6 precipitates show best creep properties.

  16. ISOLATION OF HEAT RESISTANT FUNGI FROM CANNED FRUITS

    OpenAIRE

    Sani Ibrahim; Anusha, M. B.; Udhayaraja, P.

    2014-01-01

    -Increase in the consumption of canned fruit juice rather than the fruit itself raises alarmonto the safety of these canned juices as they are stored for longer period of time unlike the fruit and dormant if spores present could germinate and cause spoilage. Heat-resistant molds are characterized by the production of ascospores or similar structures with heat resistance, in some instances comparable to bacterial spores. This enables them to survive even when they are thermally...

  17. Creep-fatigue interaction correlations for Hastelloy X and Inconel 617

    International Nuclear Information System (INIS)

    Hastelloy X and Inconel 617 are the materials for very high temperature gas-cooled reactors for multiple purposes, aiming at the maximum working temperature of 1000 deg C, and the collection of the data on their high temperature strength and the establishment of the fracture criteria as the basis of structural design have become the important subjects. However, especially the data concerning fatigue and creep fatigue are very few. As for the actual design method for high temperature structures concerning fatigue and creep fatigue, there is the ASME Boiler and Pressure Vessel Code, Section 3, Case 1592, but the temperature range of application is not higher than 1400 deg F, and the materials are limited to AISI 304, 316 and Alloy 800 H. In this study, high temperature low cycle fatigue test was carried out on Hastelloy X and Inconel 617, and the mutual effect of fatigue and creep was investigated. As for the high temperature low cycle fatigue test, strain-controlling test, cyclic creep rupture test and load-controlling test were carried out. Moreover, the parameters controlling the damage due to the accumulation of macroscopic strain in one direction were investigated, and the law of damage when the damage due to repeated strain and the damage due to the accumulation of strain in one direction arise simultaneously was studied. The results are reported. (Kako, I.)

  18. Forecasting of heat-resistance characteristics according to short-time tests of high-plastic structure-stable materials

    International Nuclear Information System (INIS)

    Possibility of operative forecasting of heat resistance characteristics, epsilonsub(y) secondary creep rate and tausub(y) durability is tested on the example of heat resisting KhN55MVTs alloy according to short-time test data. Primarily intergrain strain mode combined with material stable structure permits a quick evaluation of its serviceability under long-time static loading and high temperature. On the example of KhN55MVTs alloy it is shown that in a wide stress and temperature range the rate of secondary creeep epsilonsub(y) may be determined according to active tension, and durability tausub(p)-according to epsilonsub(y)tausub(p)=const ratio. The described operative forecasting methods shouldn't be used if during creeping intergrain slip dominates and secondary phases are precipitated

  19. Study on the heat-resistant EB curing composites

    International Nuclear Information System (INIS)

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

  20. Cholesterol and heat shock protein levels in heat resistant lines

    International Nuclear Information System (INIS)

    Increases in either the cholesterol content of cellular membranes or in the levels of heat shock proteins have independently been proposed as mechanisms of conferring heat resistance on cells. These two hypotheses were explored in a series of four stable heat resistant lines isolated from wild type and surface variants of B16 melanoma cells. The results can be summarized as follows: The free cholesterol content, expressed on a unit protein basis or as a molar ratio to phospholipid (C:PL ratio) in the heat resistant lines was similar to that in the respective parent lines with values for the C:PL ratio of 0.13 to 0.17 in the different lines. Analysis of the constitutive levels of heat shock proteins was done by measurement of the radioactivity in protein bands separated by gel electrophoresis following a two day exposure of cells to radioactive amino acids. Protein levels were quantified either by densitometer scanning of radiographs of the gels or by serial sectioning. Within the limits of resolution of the technique, no significant increases in constitutive levels of the three major heat shock proteins with subunit molecular weights of 68, 70, or 89 kilodaltons were observed in the heat resistant lines

  1. Humidity affects genetic architecture of heat resistance in Drosophila melanogaster

    DEFF Research Database (Denmark)

    Bubliy, Oleg A; Kristensen, Torsten Nygård

    2012-01-01

    Laboratory experiments on Drosophila have often demonstrated increased heritability for morphological and life-history traits under environmental stress. We used parent-offspring comparisons to examine the impact of humidity levels on the heritability of a physiological trait, resistance to heat, measured as knockdown time at constant temperature. Drosophila melanogaster were reared under standard nonstressful conditions and heat-shocked as adults at extreme high or low humidity. Mean knockdown time was decreased in the stressful dry environment, but there was a significant sex-by-treatment interaction: at low humidity, females were more heat resistant than males, whereas at high humidity, the situation was reversed. Phenotypic variability of knockdown time was also lower in the dry environment. The magnitude of genetic correlation between the sexes at high humidity indicated genetic variation for sexual dimorphism in heat resistance. Heritability estimates based on one-parent-offspring regressions tended to be higher under desiccation stress, and this could be explained by decreased environmental variance of heat resistance at low humidity. There was no indication that the additive genetic variance and evolvability of heat resistance differed between the environments. The pattern of heritability estimates suggests that populations of D. melanogaster may have a greater potential for evolving higher thermal tolerance under arid conditions.

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

    International Nuclear Information System (INIS)

    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 machininickel based alloy Hastelloy - 276 machining.

  3. Characterization of Hastelloy thin films deposited by pulsed laser ablation

    International Nuclear Information System (INIS)

    Hastelloy thin films have been deposited on carbon steel substrates at room temperature by pulsed laser ablation of bulk Hastelloy targets. Different numbers of laser pulses were used in order to obtain films of various thicknesses. Scanning electron microscopy (SEM) was used to analyze the surface morphology of the deposited films. Energy dispersion X-ray (EDX) spectroscopy and X-ray diffraction (XRD) have shown that the laser ablation process was almost congruent, and the crystallographic structure was retained in the films. In order to relate the microstructure of the film surface with its corrosion behavior, electrochemical tests in aqueous CO2 environment, such as potentiodynamic curves and linear polarization resistance, were performed. The film characteristics and their dependence on deposition parameters are presented and discussed

  4. Characterization of Hastelloy thin films deposited by pulsed laser ablation

    Science.gov (United States)

    Vignolo, M. F.; Avram, I.; Duhalde, S.; Morales, C.; Pérez, T.; Cultrera, L.; Perrone, A.; Zocco, A.

    2002-09-01

    Hastelloy thin films have been deposited on carbon steel substrates at room temperature by pulsed laser ablation of bulk Hastelloy targets. Different numbers of laser pulses were used in order to obtain films of various thicknesses. Scanning electron microscopy (SEM) was used to analyze the surface morphology of the deposited films. Energy dispersion X-ray (EDX) spectroscopy and X-ray diffraction (XRD) have shown that the laser ablation process was almost congruent, and the crystallographic structure was retained in the films. In order to relate the microstructure of the film surface with its corrosion behavior, electrochemical tests in aqueous CO 2 environment, such as potentiodynamic curves and linear polarization resistance, were performed. The film characteristics and their dependence on deposition parameters are presented and discussed.

  5. Developmentof plaster compositions that have improved heat resistance ?????????? ??????????? ???????? ?????????? ??????????????

    Directory of Open Access Journals (Sweden)

    Akulova Mariya Vladimirovna

    2013-02-01

    Full Text Available Protection of structures and materials from the adverse effects of the environment is a relevant challenge to be tacked both by the teams of researchers and workers on site. A universal method of protection contemplates the use of cladding and paints. There are classes of finishing materials that have special protective properties.Flame-resistant finishes obstruct the burning of structures, and in some cases they can even prevent inflammation. A universal method of protection is the plastering of the surface of a structure. Plastering is applicable to concrete, masonry, metal as well as timber. Development of heat resistant plaster is relevant due to numerous fires in Russia.This article represents an overview of the research into the influence of composite binders and fillers onto the physical and mechanical properties of the heat resistant plaster.Portland cement M 500 was used as a composite binder. Liquid sodium water glass with the density of 1,300 – 1,500 kg/m3 and the silicate modulus value of 2.4 – 2.8 was also applied. Glass sand with the fineness of 0.315 – 1.25, mineral wool fibers that were4 - 6 mm long (with the density of 50 kg/m3 were applied as fillers.Sugar is known as an excellent inhibitor of Portland cement. Liquid glass binders are very effective if added to heat resistant concretes and mortars. This fact was mentioned in the works of K.D. Nekrasov, A.P. Tarasov, G.P. Gorlov, B.D. Toturbiev and others, and it has been proven in practice. It is noteworthy that liquid glass demonstrates high adhesive strength in terms of all materials. Its adhesive strength is 3...5 times higher than that of the cement, and this fact can serve as the basis for the development of highquality heat-resistant solutions.The resulting composition is an excellent heat resistant plaster; its physical-mechanical and thermal properties are not inferior to heat resistant mortars based on imported additives.??????????? ???????? ?????????? ?????????????? ???????? ?????????? ????????? ?????? ???????????? ??????????? ?? ??????????? ?????????? ??????????. ????????? ???????????? ??????? ???????? ? ????????????, ????????? ????????????? ??????????? ????????????? ? ??????? ???????? ?????????? ???????????? ??? ???? ??????????. ???????? ??????????? ????????, ?????????????? ??????? ? ???? ????, ??? ? ???????? ????????.

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

    International Nuclear Information System (INIS)

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

  7. Testing Method for Heat Resistance Under Temperature Gradient

    Science.gov (United States)

    Takagi, K.; Kawasaki, A.; Itoh, Y.; Harada, Y.; Ono, F.

    2007-12-01

    “Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature gradient of materials and coated members of equipment exposed to high temperature, such as aircraft engines, gas turbines, and so on. This paper introduces the principle and overview of the established standard. In addition, taking the heat cycle test using the burner rig for instance, we specifically illustrate the acquirable data and their analysis in the standard. Monitoring of the effective thermal conductivity and acoustic emission particularly enables to the non-destructive evaluation of failure cycle.

  8. 16. lecture meeting of the Association for Heat-Resistant Steels and the Association for High-Temperature Materials, on 'Long-term performance of heat-resistant steels and high-temperature materials'. Thermal stress of materials. Proceedings

    International Nuclear Information System (INIS)

    The proceedings contain 17 contributions on the following subjects (selection): 1) Development of the microstructure of the martensitic tempered steel X22CrMoV12-1 in fatigue tests up to 80000 h. 2) Influences on creep-induced pore formation and their detection in heat-resistant, low-alloyed steels CrMoV. 3) Endurance properties of highly creep-resistant bolt and blade steel X19CrMoVNbN11-1 in fatigue tests up to 600 C. 4) Creep behaviour of a welded 'P91' pressure vessel. 5) State of the development of improved 9 to 10%-CrMoVNb steels for turbines having steam parameters of 600 C. 6) Fracture-mechanical comparison of the mixed compound X20CrMoV12-1 and G17CrMoV5-11 for determining critical defect variables. 7) Creep-to-crack behaviour of powerplant steels. 8) Behaviour of defects in forgings or castings under creep or creep-fatigue stress. 9) Behaviour of heat-resistant steels under multistage fatigue stress. 10) Connection between failure and multiaxial stress in creep loaded pipe elbows. 11) Contribution to the characterization of long-term heat resistance of steels 12CrMo9-10 and their welds. 12) Contribution to the estimation of long-term heat resistance of the higher-resistant unalloyed steel type G20Mn5, well suitable for welding. 13) Creep equations for highly creep resistant materials. (orig./MM)

  9. The effect of carbon content on the microstructure of an experimental heat-resistant steel

    International Nuclear Information System (INIS)

    The effect of carbon content on the microstructure of a HP-Nb type heat-resistant steel (35Ni-25Cr-1Nb) is examined for carbon contents of 0.35, 0.44, 0.56, and 0.62 wt%. In the cast state, the alloys contain both eutectic Cr7C3 and eutectic NbC. Upon aging, Cr23C6 carbides precipitate out from the supersaturated austenite. The distribution of the Cr23C6 carbides was better, that is, more uniform, in the alloys containing 0.44 or 0.56 wt.%C than in the alloys containing 0.35 or 0.62 wt.%C. Both the amount of the eutectic Cr7C3 carbides at the grain boundaries, and the Cr23C6 carbides within the grains, increased with increasing carbon content. The relationship between the microstructures developed and the creep and high-temperature tensile properties is briefly discussed

  10. Fatigue crack propagation in Hastelloy X weld metal

    International Nuclear Information System (INIS)

    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 = (?K)/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 ?K 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

  11. Evaluation of Hastelloy X for gas-cooled-reactor applications

    International Nuclear Information System (INIS)

    Hastelloy X is a potential structural material for use in gas-cooled reactor systems. In this application data are necessary on the mechanical properties of base metals and weldments under realistic service conditions. The test environment studied was helium that contained small amounts of H2, CH4, and CO. It is shown that this environment is carburizing with the kinetics of this process, becoming rapid above 8000C. Suitable weldments of Hastelloy X were prepared by several processes; those weldments generally had properties similar to the base metal except for lower fracture strains under some conditions. Some samples were aged up to 20,000 h in the test gas and tested, and some creep tests on as-received material exceeded 40,000 h. The predominant effect of aging was the significant reduction of the fracture strains at ambient temperature; the strains were lower when the samples were aged in HTGR helium than when aged in inert gas. Under some conditions aging also increased the yield and ultimate tensile strength. Limited impact testing showed that the impact energy at 250C was reduced drastically by aging at 871 and 7040C

  12. Heat-resistant bacterial phytase in broiler pelleted diets

    Scientific Electronic Library Online (English)

    TC de F, Carlos; LCGS, Barbosa; NN, Shiroma; RL, Dari; G, Baolin; W, Yongcheng; CS da S, Araújo; LF, Araújo.

    2015-03-01

    Full Text Available The objective of the study was to evaluate the effects of a heat-resistant bacterial phytase added to pelleted diets on mineral digestibility, live performance, carcass traits, and bone quality of broilers. Three treatments were evaluated: Positive control; negative control, with 0.10 points reducti [...] on in calcium level and 0.15 points reduction in available phosphorus level; and negative control + phytase at 500 FTU/kg. Mineral digestibility and bone quality results demonstrated that the evaluated phytase resisted pelleting as it increased the utilization of the minerals present in the diet.

  13. Permeation of hydrogen and tritium through heat resistant steels up to 9500C

    International Nuclear Information System (INIS)

    For permeation and diffusion measurements of hydrogen isotopes through heat resistant alloys with bare or oxide coated surface two new methods have been developed. The first works with high-frequency heating of a tabular sample (HF-method), and is used for steady-state hydrogen permeation in the range 700 to 9500C and H2 pressures up to 40 bar. The second method uses two gas loops (TL-method) and a disc-shaped sample in between, and is applicable also for non-steady state (time-lag) measurements. It has been used for tritium permeation between 650 and 9500C at T2 pressures of 10 to 100 ?bar. The HF-method turned out suitable for quick tests of materials behaviour, especially with respect to the overall dependence of permeation on pressure and temperature. The TL-method yields besides permeability also data on diffusivity and solubility. It proved appropriate particularly for investigating the influence of different alloy components, for instance C and Cr content in austenitic steels. With regard to the effect of oxide coatings it seems certain now that restraints of hydrogen dissociation and recombination processes are of stronger importance for the impediment of permeation than presumed so far. (orig.)

  14. The strain-controlled fatigue behavior and modeling of Haynes HASTELLOY C-2000 superalloy

    International Nuclear Information System (INIS)

    Research highlights: ? Low-cycle fatigue tests were conducted at temperatures of 24 deg. C, 204 deg. C, and 427 deg. C. ? Metallographic and fractographic characterization was performed. ? Coffin-Manson and Holloman curves were generated. ? A strain energy theoretical life prediction model was introduced. - Abstract: The strain-controlled fatigue behavior of the new nickel-chromium-molybdenum superalloy, HASTELLOY C-2000 was investigated. Low-cycle fatigue specimens were tested in strain-controlled fatigue conditions under axial strain range control at 24 deg. C, 204 deg. C and 427 deg. C. The results indicated that at total strain ranges below 0.8%, temperature does not significantly influence fatigue life, whereas at high total strain ranges, there is a significant drop in fatigue life at 427 deg. C. At room temperature and 204 deg. C, the cyclic stress response was cyclic hardening, followed by cyclic stability, cyclic hardening, or cyclic softening, depending on the total strain range. At 427 deg. C, only cyclic hardening was observed. Fractographic and metallographic analyses were also conducted. The strain-life and Holloman relation parameters are calculated. A theoretical model that predicts the life of this alloy under the tested conditions using the plastic strain energy method is also presented. The results of the theoretical model are in good agreement with the experimental results.

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

    Directory of Open Access Journals (Sweden)

    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.

  16. The strain-controlled fatigue behavior and modeling of Haynes HASTELLOY C-2000 superalloy

    Energy Technology Data Exchange (ETDEWEB)

    McDaniels, R.L., E-mail: rmcdanie@utk.edu [Department of Materials Science and Engineering, University of Tennessee, 434 Dougherty Hall, Knoxville, TN 37996-2200 (United States); Chen, L. [Department of Materials Science and Engineering, University of Tennessee, 434 Dougherty Hall, Knoxville, TN 37996-2200 (United States); School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110023 (China); Steward, R.; Liaw, P.K.; Buchanan, R.A. [Department of Materials Science and Engineering, University of Tennessee, 434 Dougherty Hall, Knoxville, TN 37996-2200 (United States); White, Steve; Liaw, Kevin [Department of Materials Science and Engineering, University of Tennessee, 434 Dougherty Hall, Knoxville, TN 37996-2200 (United States); School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110023 (China); Haynes International, Inc., 1020 West Park Avenue, P.O. Box 9013, Kokomo, IN 46904-9013 (United States); Klarstrom, D.L. [Haynes International, Inc., 1020 West Park Avenue, P.O. Box 9013, Kokomo, IN 46904-9013 (United States)

    2011-05-15

    Research highlights: {yields} Low-cycle fatigue tests were conducted at temperatures of 24 deg. C, 204 deg. C, and 427 deg. C. {yields} Metallographic and fractographic characterization was performed. {yields} Coffin-Manson and Holloman curves were generated. {yields} A strain energy theoretical life prediction model was introduced. - Abstract: The strain-controlled fatigue behavior of the new nickel-chromium-molybdenum superalloy, HASTELLOY C-2000 was investigated. Low-cycle fatigue specimens were tested in strain-controlled fatigue conditions under axial strain range control at 24 deg. C, 204 deg. C and 427 deg. C. The results indicated that at total strain ranges below 0.8%, temperature does not significantly influence fatigue life, whereas at high total strain ranges, there is a significant drop in fatigue life at 427 deg. C. At room temperature and 204 deg. C, the cyclic stress response was cyclic hardening, followed by cyclic stability, cyclic hardening, or cyclic softening, depending on the total strain range. At 427 deg. C, only cyclic hardening was observed. Fractographic and metallographic analyses were also conducted. The strain-life and Holloman relation parameters are calculated. A theoretical model that predicts the life of this alloy under the tested conditions using the plastic strain energy method is also presented. The results of the theoretical model are in good agreement with the experimental results.

  17. Heat resistant plate for thermonuclear reactor and its manufacturing method

    International Nuclear Information System (INIS)

    Low Young modulus ingredients, high strength materials, porous or ceramic fibers have been distributed as the third ingredient in gradation functional materials so as to obtain high temperature resistance and toughness for as heat resistant materials for a thermonuclear reactor. However, they are distributed only in the middle layer and, when cracks are caused to the surface layer by thermal shocks, etc., the cracks are expected to be developed easily to cause peeling and rupture of the surface. In the present invention, the surface layer on the heat receiving side comprises fiber-reinforced materials, the surface layer on the heat releasing side comprises heat resistant materials and/or fiber-reinforced materials, in which the material ingredient ratio in the intermediate layer between them is determined so as to vary continuously or stepwise. As a result, high temperature resistance and high temperature toughness can be improved, thereby enabling to prevent peeling, detachment, rupture and progress of cracks due to thermal shocks and thermal stresses. Further, damages due to evaporation from the surface layer on the heat receiving side is extremely reduced to extend the life of materials. Formation of long-life radioactive elements from the heat receiving surface can be suppressed. (N.H.)

  18. Effect of structure of precipitation hardened heat-resistant steel on avalanchet crack growth mechanism under creep conditions

    International Nuclear Information System (INIS)

    15Kh1M1FL and 20KhMFL pearlitic chromium-molybdenum cast steels are of special interest when investiagting the effect of structure on fracture toughness. Metal of four commercial castings from 15Kh1M1FL steel in different structural state was used for the experiment. Metal of two castings from 20KhMFL steel with lower content of alloying elements (molybdenum, chromium and vanadium) was investigated as well: one casting was in delivery state, the other - after operation during 107 Th.h (metal yield limit is 505 MPa and 390 MPa, respectively). Connection of heat-resistant steel fracture with solid solution alloying level, finely-dispersed particles in spaces between large (with diameter more, than 0.15 mkm) carbides and dislocation density is shown

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

    Directory of Open Access Journals (Sweden)

    Chenhui Zhao

    2012-12-01

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

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

    International Nuclear Information System (INIS)

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

    OpenAIRE

    Chenhui Zhao; Guangcheng Zhang; Aihua Shi

    2012-01-01

    Three heat resistant cross-linked PVC foam plastics were prepared and their performances were compared with universal cross-linked PVC structural foam. The results show that these three heat resistant foams have higher glass transition temperatures (close to 100 °C) than universal structural foam (83.2 °C). Compared with the universal structural foam, the three heat resistant foams show much higher decomposition temperature and better chemical stability due to the crosslinki...

  2. SR X-ray analysis of Ni-based alloys corroded in molten fluoride salt

    International Nuclear Information System (INIS)

    Corrosion test of Ni-based high temperature alloys of Inconel 600, Hastelloy X and Hastelloy c-276 were performed in molten fluoride salt(LiNaKF) at 750 degree C for up to 320 h. The virgin and corroded samples were imaged by scanning electron microscope, analyzed by synchrotron radiation microbeam X-ray fluorescence(?-XRF) and characterized by X-ray diffraction(XRD). The ?-XRF results show that corrosion of the Ni-based alloy in molten fluoride salt is mainly due to the erosion of alloying element Cr. The XRD results show that the alloying element Mo of Hastelloy c-276 formed the Mo2C structure, which can enhances anti-corrosive performance of the alloy in molten fluoride salt. (authors)

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

    Energy Technology Data Exchange (ETDEWEB)

    Tsukamoto, O [Yokohama National University, Faculty of Engineering, 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan); Ciszek, M [Polish Academy of Sciences, Institute of Low Temperature and Structure Research, ulica Okolna 2, 50-422 Wroclaw (Poland)

    2007-10-15

    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.

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

    International Nuclear Information System (INIS)

    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)

  5. Oxidation characteristics of oxide dispersion strengthened (ODS) alloy

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, Tomio; Watanabe, Katsutoshi; Shindo, Masami [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-01-01

    For the feasibility study of an oxide dispersion strengthened (ODS) alloy to apply to a high temperature structural material in advanced High Temperature Gas-cooled Reactors (HTGRs) and heat utilization systems of HTGR, the oxidation tests of Fe-Cr-Al-Y{sub 2}O{sub 3}-based ODS alloy in the simulated HTGR helium environment and the air were carried out together with two kinds of high temperature alloys, i.e., Hastelloy XR and Ni-Cr-W alloys. It was clarified that the ODS alloy had excellent oxidation characteristics in both the environments due to the formation of protective Al-based oxide scale with dispersed Y{sub 2}O{sub 3} on the alloy surface. Furthermore, the comparison between Hastelloy XR and Ni-Ci-W alloys on the oxidation behavior was also discussed. (author).

  6. Oxidation characteristics of oxide dispersion strengthened (ODS) alloy

    International Nuclear Information System (INIS)

    For the feasibility study of an oxide dispersion strengthened (ODS) alloy to apply to a high temperature structural material in advanced High Temperature Gas-cooled Reactors (HTGRs) and heat utilization systems of HTGR, the oxidation tests of Fe-Cr-Al-Y2O3-based ODS alloy in the simulated HTGR helium environment and the air were carried out together with two kinds of high temperature alloys, i.e., Hastelloy XR and Ni-Cr-W alloys. It was clarified that the ODS alloy had excellent oxidation characteristics in both the environments due to the formation of protective Al-based oxide scale with dispersed Y2O3 on the alloy surface. Furthermore, the comparison between Hastelloy XR and Ni-Cr-W alloys on the oxidation behavior was also discussed. (author)

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

    OpenAIRE

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

    2011-01-01

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

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

    OpenAIRE

    Takahide Fukuyama; Yu Mukai; Ilhyong Ryu

    2011-01-01

    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.

  9. Swelling in neutron irradiated nickel-base alloys

    International Nuclear Information System (INIS)

    Inconel 625, Incoloy 800 and Hastelloy X were neutron irradiated at 500 to 7000C. It was found that of the three alloys investigated, Inconel 625 offers the greatest swelling resistance. The superior swelling resistance of Inconel 625 relative to that of Hastelloy-X is probably related to differences in the concentrations of the minor rather than major alloy constituents, and can involve (a) enhanced recombination of defects in the Inconel 625 and (b) preferential attraction of vacancies to incoherent precipitates. (U.S.)

  10. 15. lecture meeting of the Association for heat-resistant steels and the Association for high-temperature materials, on ''Long-term performance of heat-resistant steels and high-temperature materials''. Thermal stress of materials

    International Nuclear Information System (INIS)

    The proceedings contain 15 contributions with the following titles: 1. Documentation of fatigue data and preparation for the evaluation with the ZSF program system; 2. Evaluation of strain limit-spread bands with the DESA program; 3. Evaluation of fatigue data with the MCM program; 4. Calculated evaluation of fatigue tests with the example of steel 13 CrMo 4 4; 5. How to improve the creep properties of modified chromium steels; 6. Development work at Nb-stabilized martensitic 9 to 12% chromium steels for applications in energy technology; 7. Microstructure and deformation of the steel X 20 CrMoV 12 1 at high temperature; 8. Influence of multiaxial stress on the long-term creep processes in steels; 9. Determination of the lifetime of an austenitic big-sized plate under creep-fatigue stress - comparative evaluations of design calculation and experiment; 10. Experimental and calculated examination of the fatigue performance of notched specimens; 11. Structure-property relations at heat resistant pipe steel 15 CrMoV 5 10; 12. Results of the quantitative structural analysis of long-term stressed 15 CrMoV 5 10 and 14 MoV 6 3; 13. Behaviour of protective coatings on high temeprature materials under cyclical stress; 14. Mechanical endurance of nickel-base alloys in the high temperature range; 15. Influence of scaling on the fatigue performance of heat resistant steels. (orig./MM)

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

    International Nuclear Information System (INIS)

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

  12. Heterogeneity of heat-resistant proteases from milk Pseudomonas species.

    Science.gov (United States)

    Marchand, Sophie; Vandriesche, Gonzalez; Coorevits, An; Coudijzer, Katleen; De Jonghe, Valerie; Dewettinck, Koen; De Vos, Paul; Devreese, Bart; Heyndrickx, Marc; De Block, Jan

    2009-07-31

    Pseudomonas fragi, Pseudomonas lundensis and members of the Pseudomonas fluorescens group may spoil Ultra High Temperature (UHT) treated milk and dairy products, due to the production of heat-stable proteases in the cold chain of raw milk. Since the aprX gene codes for a heat-resistant protease in P. fluorescens, the presence of this gene has also been investigated in other members of the genus. For this purpose an aprX-screening PCR test has been developed. Twenty-nine representatives of important milk Pseudomonas species and thirty-five reference strains were screened. In 42 out of 55 investigated Pseudomonas strains, the aprX gene was detected, which proves the potential of the aprX-PCR test as a screening tool for potentially proteolytic Pseudomonas strains in milk samples. An extensive study of the obtained aprX-sequences on the DNA and the amino acid level, however, revealed a large heterogeneity within the investigated milk isolates. Although this heterogeneity sets limitations to a general detection method for all proteolytic Pseudomonas strains in milk, it offers a great potential for the development of a multiplex PCR screening test targeting individual aprX-genes. Furthermore, our data illustrated the potential use of the aprX gene as a taxonomic marker, which may help in resolving the current taxonomic deadlock in the P. fluorescens group. PMID:19481283

  13. Studies Concerning Heat-Resisting Additives for Bitumens

    Directory of Open Access Journals (Sweden)

    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.

  14. Behaviour of heat-resistant steels under multistage fatigue stress

    International Nuclear Information System (INIS)

    Four heat-resistant steels (10 CrMo 9 10, 28 CrMoNiV 4 9, X 22 CrMoV 12 1, X 6 CrNiMo 17 13), were used to examine the fatigue under multistage rectangular cyclic stress. The load cycles were made to be similar to the stress affecting power plant components. These are mainly cycles with decreasing and/or increasing stresses, with the temperature or both variables at the same time having been varied in some cases. As characteristical parameters of the modified life-fraction rule, the relative fracture life and for characterizing strains the relative strain life as well were determined. For the assessment of the relative life under any multistage stress, a new step hypothesis, applicable to all possible elementary stress steps, was developed. This hypothesis is able to predict even a consequential effect by means of additional rules. In comparison to this hypothesis, the simple life fraction rule which is unapt for single-stage stress, results in a somehow better prognosis of the fraction time and strain endurance limits under multistage stress. (orig./MM)

  15. A new class of bio-heat resisted polymer blend.

    Science.gov (United States)

    Pack, Seongchan; Kashiwagi, Takashi; Koga, Tadanori; Rafailovich, Miriam

    2009-03-01

    Increasing in oil prices and environmental concerns is a driving force to seek out alternative materials. A completely biodegradable starch is a candidate for the alternative materials. Since the starch is brittle, it must be mixed with other polymers. In order to make a thermoplastic starch (TPS), we need a bio-compatiblizer to increase a degree of compatibilization. The biocompatibilzer can be a small molecules or nanoparticles with the small molecules, which leads to improved material properties. In order to demonstrate a possible biocompatibilzer, we first developed a corn-based starch impregnated with non-halogenated flame retardant formulations. The starch was blended with Ecoflex, a biodegradable polymer. Using SAXS and USAXS we characterized structures of the compounds with different amount of Ecoflex by weight. Furthermore, the addition of 5% nanoparticles in the compounds increased the Young's Modulus and impact toughness significantly. The compounds also did flame test. It is indicated that the compound with the addition of the nanopaticles would pass with a UL-94V0 rating. Therefore, the procedure for producing these TPS compounds can be applied to any biodegradable polymers, manufacturing a new bio-heat resisted compound.

  16. Effect of grain size on creep and creep-rupture properties of hastelloy X

    International Nuclear Information System (INIS)

    Effect of grain size variation between 60 ?m and 350 ?m on creep and creep-rupture properties was studied on Ni-base alloy Hastelloy X. Creep and creep-rupture tests were carried out at 800, 900 and 10000C for durations up to about 103 h. At the same time, measurements of the number and size of grain boundary cavities were conducted through longitudinal sections of specimens which were unloaded during creep deformation by means of optical microscopy of 100 sup( x) magnification, and the relation between grain boundary cavitation and creep deformation was obtained. Rupture life decreased with increase of grain size at 8000C, but, at 10000C,increased with increase of grain size. Rupture life at 9000C was little affected by grain size variation. Grain boundary cavities below 20/mm2 initiated at the time of starting of the tertiary creep range. The higher rupture strength of finer grain size materials at 8000C corresponded to the phenomena that the number and size of grain boundary cavities at constant crept time and the number of grain boundary cavities at constant creep strain decreased as grain size decreased. These phenomena at 8000C show the ease of initiation and growth of grain boundary cavities in coarser grain size materials and are considered to be due to cohesion of the carbides near the grain boundaries. The higher rupture strength of coarser grain size materials at 10000C corresponded to the phenomena that the number and size of grain boundary cavities at constant crept time decreased as grain size increased and linkage of the cavities occurred in the early creep region for finer grain size materials. These phenomena at 10000C which show difficulty of initiation and growth of grain boundary cavities in coarser grain size materials may be attributed to a continuous precipitation of the carbides at the grain boundaries. (author)

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

    Science.gov (United States)

    Manda, M.; Jacobson, D.

    1978-01-01

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

  18. Structure degradation of 25Cr35Ni heat-resistant tube associated with surface coking and internal carburization

    Energy Technology Data Exchange (ETDEWEB)

    Wu, X.Q.; Yang, Y.S.; Zhan, Q.; Hu, Z.Q. [Chinese Academy of Sciences, Shenyang (China)

    1998-10-01

    Microstructures of 25Cr35Ni heat-resistant cracking tube after service were investigated and degradation mechanism of tube material was discussed. Results reveal that three distinguished zones, that is, internal oxide, carbide free, and internally carburized zones, will gradually develop in the inner wall of a cracking tube during service. Carbide free and internally carburized zones are formed primarily in relation to the periodic spalling and regeneration of surface oxide scale, and diffusion velocity of carbon and carbide forming elements in matrix and the solubility limit of carbon in alloy. The formation and growth of filament coke can aggravate structure degradation of the inner wall of the cracking tube, while deposition of lamellar and spheroidal coke may slow structure degradation to some extent. Surface coking and decoking cycles strongly aggravate the structure degradation of tube material and damage the service life of the cracking tube.

  19. Genome-wide deficiency screen for the genomic regions responsible for heat resistance in Drosophila melanogaster

    Directory of Open Access Journals (Sweden)

    Teramura Kouhei

    2011-06-01

    Full Text Available Abstract Background Temperature adaptation is one of the most important determinants of distribution and population size of organisms in nature. Recently, quantitative trait loci (QTL mapping and gene expression profiling approaches have been used for detecting candidate genes for heat resistance. However, the resolution of QTL mapping is not high enough to examine the individual effects of various genes in each QTL. Heat stress-responsive genes, characterized by gene expression profiling studies, are not necessarily responsible for heat resistance. Some of these genes may be regulated in association with the heat stress response of other genes. Results To evaluate which heat-responsive genes are potential candidates for heat resistance with higher resolution than previous QTL mapping studies, we performed genome-wide deficiency screen for QTL for heat resistance. We screened 439 isogenic deficiency strains from the DrosDel project, covering 65.6% of the Drosophila melanogaster genome in order to map QTL for thermal resistance. As a result, we found 19 QTL for heat resistance, including 3 novel QTL outside the QTL found in previous studies. Conclusion The QTL found in this study encompassed 19 heat-responsive genes found in the previous gene expression profiling studies, suggesting that they were strong candidates for heat resistance. This result provides new insights into the genetic architecture of heat resistance. It also emphasizes the advantages of genome-wide deficiency screen using isogenic deficiency libraries.

  20. Influence of pH on heat resistance of Bacillus licheniformis in buffer and homogenised foods.

    Science.gov (United States)

    Palop, A; Raso, J; Pagán, R; Condón, S; Sala, F J

    1996-02-01

    The influence of pH of heating menstruum (McIlvaine buffer) on the heat resistance of Bacillus licheniformis was investigated and compared with the heat resistance in homogenised tomato and asparagus at pH 7 and 4 in a wide range of temperatures. Heat resistance was in all mestrua smaller at acid pH. At 99 degrees C and pH 4, heat resistance was 1/20 lower than at pH 7. However, the magnitude of this effect decreased as heat treatment temperatures were increased almost disappearing at 120 degrees C. z values increased from 6.85 at pH 7, to 10.75 at pH 4. At 99 degrees C the effect of pH on heat resistance was constant along the range of pH's tested. The increase of one pH unit increased D99 by 180%. At pH 7 and 4, heat resistance was the same in buffer as in tomato and asparagus homogenates at all temperatures tested. The diminishing influence of the acidification of some foods on the heat resistance of B. licheniformis sterilisation temperatures should be taken into account when a raise in temperature is considered to shorten the duration of heat processes. PMID:8722182

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

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

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

  2. Creep properties of hastelloy x and their application to the structural design

    International Nuclear Information System (INIS)

    In the creep curve of Hastelloy X, it was difficult to divide it into the three stages of creep. However, these stages were made distinguishable by plotting the relationship between creep rates and time in double-logarithmic coordinates. All the creep data of Hastelloy X, except the isochronous stress-strain curves, required for determining the design stress intensities S sub(o) and S sub(t) were arranged through the Larson-Miller parameter. The isochronous stress-strain curves for a heat of Hastelloy X were derived from the constitutive equations obtained from short-term data. A fairly good agreement between the predicted data and the experimental data was obtained. (auth.)

  3. Trends in the development of heat resistant steels for seamless tubes in power station construction

    International Nuclear Information System (INIS)

    The requirements for heat resistant steels for power station construction have changed. Good properties in relation to resistance to heat are taken for granted; today the key points of interest are ductility at low temperatures and weldability requirements. The erratic increases in the price of fossil fuels lead to increase in steam temperature and pressure just as the construction of advanced reactors automatically leads to the use of heat-resistant austenitic steels. (orig.)

  4. Structure and properties of heat-resistant maraging steels

    Energy Technology Data Exchange (ETDEWEB)

    Bityukov, S.M.; Grachev, S.V.; Zvigintsev, N.V.; Lisin, V.N.; Rundkvist, N.A.; Chervinskij, V.F. (Ural' skij Politekhnicheskij Inst., Sverdlovsk (USSR))

    1982-01-01

    A study was made on resistance of maraging steels on the base of Fe-Cr-Mo-Co under conditions of low-cycle thermal fatigue test. Intermetallic R- and X-phases in these steels arise in martensite and austenite respectively. 06Kh13K16M5 steel at temperatures of test up to 550 deg C sufficiently exceeds Kh20N77T2YuR nickel based alloy in strength and stability of geometric sizes.

  5. Heat treatment of nickel alloys

    International Nuclear Information System (INIS)

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

  6. Hydrogen transport in nickel base stainless alloys

    Science.gov (United States)

    Mezzanotte, David A.; Kargol, James A.; Fiore, Nicholas F.

    1982-07-01

    Hydrogen transport parameters have been measured in two nickel base stainless alloys, HASTELLOY Alloys C-276 and G. Hydrogen diffusivity and permeability were determined by means of the electrolytic permeability technique over the temperature range of 17 to 90 °C. Although the two alloys are similar in composition and structure, they exhibited dramatically different hydrogen behavior. For Alloy C-276, the diffusivity in both the cold worked and annealed conditions decreased by a factor of two following low temperature (500 °C) aging. That behavior was related to ordering in the alloy. Unexpectedly, hydrogen trapping was not observed in Alloy C-276. An analysis of hydrogen transport in Alloy G indicated reversible and irreversible trapping of hydrogen by niobium substitutional atoms and second phase carbides, respectively. The hydrogen transport results were related to the hydrogen embrittlement tendencies of the two nickel base alloys.

  7. Structure and properties of heat-resistant maraging steels

    International Nuclear Information System (INIS)

    A study was made on resistance of maraging steels on the base of Fe-Cr-Mo-Co under conditions of low-cycle thermal fatigue test. Intermetallic R- and X-phases in these steels arise in martensite and austenite consequently, at the same time their existence is possible both in one and another phases. 06Kh13K16M5 steel at temperatures of test up to 550 deg C sufficiently exceeds Kh20N77T2YuR nickel based alloy in strength and stability of geometric sizes and can be used for the most loaded detailes excluding large deformations

  8. Carburization behaviour of high temperature alloys in carburizing environment

    International Nuclear Information System (INIS)

    In studying the carburization behaviour of high temperature alloys, carburization tests in heavy carburizing environment were undertaken on several potential candidate alloys for uses in HTR system. The alloys tested were R 4286 developed by ERANS (Engineering Research Association of Nuclear Steel-making) programme, Ni-18.5 % Cr-21.5 % W as identified F alloy, Hastelloy XR and Hastelloy XR-II, and the test environment conditions employed were (Ar + 10 % CH4) gas at 800, 850, 900 and 950 deg C for up to 100 hours. It is shown that when no protective surface oxide layer is formed, the carburization kinetics follows a parabolic rate law, and the alloying additions of Al and Ti have a beneficial effect in dry environment (very low oxidizing) on the carburization resistance due to the formation of Al-Ti-based oxide and without formation of Cr-based oxide. In the comparison of the carburization resistance of the alloys tested, R 4286 containing 2 % Al and 2.5 % Ti exhibits the best resistance due to the formation of the protective Al-Ti-based oxide and the F alloy shows a moderate resistance, while Hastelloys XR and XR-II are found to have the lowest resistance. (author)

  9. Creep properties of Hastelloy X and their application to structural design

    International Nuclear Information System (INIS)

    Creep and stress rupture tests on three heats of Hastelloy X differing in the manufacturing process were carried out at 8000C, 9000C and 10000C. Interpretation of the observed creep properties was made, and a method for predicting necessary design data from the experimentally obtained results was discussed. The results are as follows. (1) It was difficult to separate the primary, secondary and tertiary creep stages in the creep curve of Hastelloy X of the present tests. However, those were made distinguishable by plotting the results in a double-logarithmic coordinates. From these creep rate curves, the primary and secondary creep rates and the times to the initiation of secondary and tertiary creeps were derived. (2) It is considered that the same stress and temperature dependences between the primary and secondary creep rates exist in the creep behaviour of Hastelloy X of the present tests. (3) All the creep data, except the isochronous stress-strain curve, required for the design such as stress vs. rupture time, stress vs. secondary creep rate and stress vs. time to initiation of tertiary creep could be arranged through the Larson-Miller parameter. On the other hand, the isochronous stress-strain curve was figured out by estimating creep curves. The constitutive equations of creep for a heat of Hastelloy X proposed in this paper and the isochronous stress-strain curves derived from these constitutive equations were consistent with tstitutive equations were consistent with the experimental data obtained for the corresponding material. (auth.)

  10. Regularities of changes of high-temperature hardness in Nb-ZrN and Nb-HfN system alloys

    International Nuclear Information System (INIS)

    Heat resistance of casted niobium alloys of two quasibinary systems is studied by the method of high-temperature hardness. The composition heat resistance curve is calculated for the case of short-term hardness taking into consideration structural peculiarities of studied alloys and all possible hardening mechanisms-dispersed, compositional and deformation hardening. The calculated curve is shown to be in a good correlation with the experimental one. A conclusion is made that a character of composition-heat resistance curve for two- phase alloy systems is determined mainly by the size change of strengthening phase at the increase of its volume content

  11. Preselection of Ni-Cr(-Mo) alloys as potential canister materials for vitrified high active nuclear waste by electrochemical testing

    Science.gov (United States)

    Bort, H.; Wolf, I.; Leistikow, S.

    1987-07-01

    Several Ni-Cr(-Mo) alloys (Hastelloy C4, Inconel 625, Sanicro 28, Incoloy 825, Inconel 690) were tested by electrochemical methods to characterize their corrosion behavior 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 was tested by potentiodynamic, potentiostatic and galvanostic measurements. As electrolytes H 2SO 4 solutions were used, as parameters temperature, chloride content and pH-value were varied. All tested alloys showed a clearly limited resistance against pitting corrosion phenomena; under severe conditions even crevice corrosion phenomena were observed. The best corrosion behavior, however, is shown by Hastelloy C4, which has the lowest passivation current density of all tested alloys and the largest potential region with protection against local corrosion phenomena.

  12. Plasticity of nickel and its alloys

    International Nuclear Information System (INIS)

    The possibility has been investigated of increasing the plasticity of nickel NP-2, Nichrome Kh20N80 and the heat-resistant alloy KhN55VMTFKYu (EhI929) by creating an ultra-fine-grain structure in them; the influence of deformation in conditions of high plasticity on changes in the high-temperature strength properties of the EhI929 alloy after final thermal treatment was likewise studied. Deformation of EhI929 in conditions of enhanced plasticity leads, after standard thermal treatment, to the disappearance of irregular granularity and to complete regeneration of heat-resistant properties. (author)

  13. Electrochemical Impedance Spectroscopy Of Metal Alloys

    Science.gov (United States)

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

    1993-01-01

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

  14. alloys

    Science.gov (United States)

    Pan, Z. B.; Liu, J. J.; Wang, R.; Liu, X. Y.; Wang, J.; Sun, N. K.; Si, P. Z.

    2014-06-01

    Structural, magnetic and magnetostrictive properties of Tb0.4Nd0.6(Fe0.8Co0.2) x (1.50 ? x ? 1.90) alloys have been investigated by means of X-ray diffraction (XRD), a vibrating sample magnetometer and a standard strain technique. XRD analysis shows the presence of single Laves phase with a cubic MgCu2-type structure for the high Nd content alloy around the composition of x = 1.80, which tends to be formed by curing at relatively low annealing temperature. The easy direction of magnetization at room temperature is observed toward axis, accompanied by a rhombohedral distortion with a large spontaneous magnetostriction ?111. An optimized effect on the linear anisotropic magnetostriction, 360 ppm at 3 kOe, was observed for the high Nd content Tb0.4Nd0.6(Fe0.8Co0.2)1.80 alloy, which can be attributed to its single Laves phase, the large ?111 (~1,520 ppm) of the MgCu2-type (Tb,Nd)(Fe,Co)2 phase and the good soft magnetic behaviors.

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

    OpenAIRE

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

    2006-01-01

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

  16. Development of heat-resistant FBG sensor for high temperature structures monitoring

    International Nuclear Information System (INIS)

    Strain sensors, which can be used for integrity monitoring of plant components and piping during the operation period continuously, are effective from the point of view of proactive maintenance. FBG (Fiber Bragg Grating) sensor is one of the expective sensors and is used in various plants and civil engineering and construction fields except for high temperature service. In order to apply to the component and piping of fast reactor, heat resistance is an indispensable feature of the sensor. In this study, we tried to improve heat resistance of FBG by using femtosecond laser in the process. The heat resistance at the FBGs was examined experimentally and the results compared with those of ordinary FBGs. (author)

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

    International Nuclear Information System (INIS)

    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

  18. Modern aluminium magnesium alloys and composites developed on their base

    International Nuclear Information System (INIS)

    A review is presented on properties of high-strength aluminium and magnesium base alloys used, in particular, in nuclear industry during production of enriched uranium 235 (V96Ts). Alloy systems of Al-Cu-Li, Al-Cu-Mg, Mg-Nd-Y-Zr are considered. Processing, strength, corrosion properties of the alloys are reported. For heat resistant alloys the fields of application and the ranges of working temperatures are pointed out

  19. Transformation processes during annealing of Al-amorphous alloys

    OpenAIRE

    Petrescu, N.; Petrescu, M.; Calin, M.; Jianu, A.; Fecioru, M.

    1993-01-01

    As the amorphous aluminum alloys represent the newest achievement in rapid solidification of Al-based high strength heat resistant materials, a study was undertaken on the amorphous alloys in the Al-RE-TM system, the rare-earth metal being a lanthanide mixture and the transition metal a Ni-Fe substitution in definite proportions. The decomposition on heating of the most highly alloyed amorphous alloy in the investigated series is characterized by differential thermal analysis, electron micros...

  20. Effect of structural instability and oxidation on heat resisting alloy endurance at high temperatures

    International Nuclear Information System (INIS)

    A joint effect of structural state and oxidation specified by a preliminary isothermal exposition on fatigue resistance of the nickel superalloy under conditions of the pure bending with rotation is studied. An increase of the limited fatigue ranges due to the ageing at the moderate temperatures (to 0.6 Tsub(melt)) and their decrease during ageing under conditions of higher temperatures are established. Oxidation of the surface exerts a noticeable action on the fatigue damage at high amplitudes of the variable stresses. At the low values of amplitudes their fatigue is mainly determined by the structural state of the material

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

    International Nuclear Information System (INIS)

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

  2. Cast, heat-resistant austenitic stainless steels having reduced alloying element content

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, Govindarajan [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Pankiw, Roman I [Greensburg, PA

    2010-07-06

    A cast, austenitic steel composed essentially of, expressed in weight percent of the total composition, about 0.4 to about 0.7 C, about 20 to about 30 Cr, about 20 to about 30 Ni, about 0.5 to about 1 Mn, about 0.6 to about 2 Si, about 0.05 to about 1 Nb, about 0.05 to about 1 W, about 0.05 to about 1.0 Mo, balance Fe, the steel being essentially free of Ti and Co, the steel characterized by at least one microstructural component selected from the group consisting of MC, M.sub.23C.sub.6, and M(C, N).

  3. Cast, heat-resistant austenitic stainless steels having reduced alloying element content

    Science.gov (United States)

    Muralidharan, Govindarajan [Knoxville, TN; Sikka, Vinod Kumar [Oak Ridge, TN; Maziasz, Philip J [Oak Ridge, TN; Pankiw, Roman I [Greensburg, PA

    2011-08-23

    A cast, austenitic steel composed essentially of, expressed in weight percent of the total composition, about 0.4 to about 0.7 C, about 20 to about 30 Cr, about 20 to about 30 Ni, about 0.5 to about 1 Mn, about 0.6 to about 2 Si, about 0.05 to about 1 Nb, about 0.05 to about 1 W, about 0.05 to about 1.0 Mo, balance Fe, the steel being essentially free of Ti and Co, the steel characterized by at least one microstructural component selected from the group consisting of MC, M.sub.23C.sub.6, and M(C, N).

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

    International Nuclear Information System (INIS)

    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.)

  5. Study of radiative properties of heat resisting metals and alloys, (1)

    International Nuclear Information System (INIS)

    The heat radiative properties of Ni, Co, and Cr were investigated. The test samples were made of electrolytic nickel, rolled cobalt sheet and chromium ingot. The purities of Ni and Co were 99.9 percent, and that of Cr 99 percent. The spectroscopic properties of the samples were measured and analyzed. In the case of Ni, the light absorption mechanism by the conductive electrons was dominant in the wavelength region of near-infrared and infrared radiation, and the temperature region up to 1700 degree K. The values of the radiation properties vary continuously. In the case of Co, a wide absorption band of the inter-band quantum transition appeared in the near-infrared region in the hcp region below 500 degree K. In the transformation temperature region, remarkable heat hysteresis characteristics were seen. In the case of Cr, a wide absorption band was also seen in the near-infrared region. However, the phase transformation and the thermal hysteresis were not observed. The optical constants of Ni, Co and Cr are well explained by a dispersion formula and the formulas concerning its parameters. (Kato, T.)

  6. Study ofof weld morphology on thin Hastelloy C-276 sheet of Study weld morphology on thin Hastelloy C-276 sheet of pulsed laser welding pulsed laser welding

    Science.gov (United States)

    Wu, Dongjiang; Ma, Guangyi; Guo, Yuquan; Guo, Dongming

    In this paper, it was indicated that the laser welding was well suitable to joining of thin Hastelloy C-276 sheet (0.5 mm thickness), and also the fine grain were observed in welding zone with invisible HAZ (heat affected zone). In addition, the smooth weld joint could be controlled by means of the laser parameter adjustment. On the other hand, it's proposed that Ni-Cr-Co-Mo and austenite CFe15.1 cubic face-centered crystal structure should be existed in as-received and welding samples, as well as the cause of FWHM (Full Width at Half Maximum) widened and peak offset of joined samples were analyzed.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-09-15

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

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

    Science.gov (United States)

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

    2013-09-01

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

  10. Frictional and heat resistance characteristics of coconut husk particle filled automotive brake pad

    Science.gov (United States)

    Bahari, Shahril Anuar; Chik, Mohd Syahrizul; Kassim, Masitah Abu; Som Said, Che Mohamad; Misnon, Mohd Iqbal; Mohamed, Zulkifli; Othman, Eliasidi Abu

    2012-06-01

    The objective of this study was to determine the friction and heat resistance characteristics of automotive brake pad composed with different sizes and percentages of coconut husk particle. The materials used were phenolic resin (phenol formaldehyde) as binder, copper, graphite and brass as friction producer/modifiers, magnesium oxide as abrasive material, steel and barium sulfate as reinforcement while coconut husk particle as filler. To obtain particle, the coconut husk was ground and dried to 3% moisture content. Then the coconut husk particle was screened using 80 mesh (to obtain coarse dust) and 100 mesh (to obtain fine dust). Different percentages of particle, such as 10 and 30% were used in the mixture of brake pad materials. Then the mixture was hot-pressed to produce brake pad. Chase machine was used to determine the friction coefficient in friction resistance testing, while thermogravimetric analyzer (TGA) machine was used to determine the heat decomposition values in heat resistance testing. Results showed that brake pad with 100 mesh and 10% composition of coconut husk particle showed the highest friction coefficient. For heat resistance, brake pad with 100 mesh and 30% composition of coconut husk dust showed the highest decomposition temperature, due to the high percentage of coconut husk particle in the composition, thus increased the thermal stability. As a comparison, brake pad composed with coconut husk particle showed better heat resistance results than commercial brake pad.

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

    Science.gov (United States)

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

    2013-03-01

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

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

    International Nuclear Information System (INIS)

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

  13. Evaluation of candidate alloys for the construction of metal flex hoses in the STS launch environment

    Science.gov (United States)

    Ontiveros, Cordelia

    1988-01-01

    Various vacuum jacketed cryogenic supply lines at the Shuttle launch site use convoluted flexible expansion joints. The atmosphere at the launch site has a very high salt content, and during a launch, fuel combustion products include hydrochloric acid. This extremely corrosive environment has caused pitting corrosion failure in the flex hoses, which were made of 304L stainless steel. A search was done to find a more corrosion resistant replacement material. This study focused on 19 metal alloys. Tests which were performed include electrochemical corrosion testing, accelerated corrosion testing in a salt fog chamber, long term exposure at the beach corrosion testing site, and pitting corrosion tests in ferric chloride solution. Based on the results of these tests, the most corrosion resistant alloys were found to be (in order) Hastelloy C-22, Inconel 625, Hastelloy C-276, Hastelloy C-4, and Inco Alloy G-3. Of these top five alloys, the Hastelloy C-22 stands out as being the best of those tested for this application.

  14. Creep crack growth behavior of several structural alloys

    Science.gov (United States)

    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.

  15. Alloys

    Science.gov (United States)

    Jung, Sung-Jin; Kim, Seong Keun; Park, Hyung-Ho; Hyun, Dow-Bin; Baek, Seung-Hyub; Kim, Jin-Sang

    2014-06-01

    The effects of mechanical deformation and subsequent annealing on the thermoelectric properties and microstructure have been investigated for p-type (Bi0.25Sb0.75)2Te3 alloys prepared by melting followed by quenching. The mechanically deformed pellets were prepared by repetition of cold-pressing of quenched samples at room temperature. Cold-pressed pellets were then annealed at 300°C in vacuum, and the thermoelectric properties and microstructure were traced through the course of the heat treatment. For the heavily deformed samples, the Seebeck coefficient rapidly increased at the very early stage of annealing and did not change as the annealing time increased, due to recrystallization of a new ?-phase which equilibrated at the annealing temperature of 300°C (?300-phase). At the initial stage of annealing (recovery stage), the electrical resistivity sharply increased, probably due to the interaction of antistructural defects with vacancies produced during the cold-pressing treatment. However, for the lightly deformed samples, recrystallization occurred only at some portion of the grain boundaries, and the newly generated ?300-phase slowly replaced the original, as-solidified ?ingot-phase.

  16. Corrosion resistant alloy uses in the power industry

    International Nuclear Information System (INIS)

    Nickel-base alloys have been used as cost-effective measures in a variety of severely corrosive situations in pollution control units for coal-fired power plants. Cost effectiveness and practical answers to corrosion problems are illustrated (specifically the wallpaper concept/metallic lining technique). Numerous cases of successful use of HASTELLOY alloys in Flue Gas Desulfurization (FGD) systems and hazardous waste treatment incineration scrubber systems are listed. In this paper developments in nickel-base alloys and their use in FGD and other segments of the power industry are discussed. In the Ni-Cr-Mo-W alloy family, the C-22 alloy has the best resistance to localized corrosion in halide environments (chloride/fluoride-containing solutions). This alloy is also used effectively as a universal filler metal to weld less-resistant alloys were weld corrosion may be a problem. Field performance of this alloy in the power industry is described

  17. The influence of heat-resisting coatings on the thermal stress state of GTE blade models under conditions of nonstationary heat exchange

    Science.gov (United States)

    Kravchuk, L. V.; Semenov, G. R.; Borovkov, V. A.

    1994-06-01

    The calculation of thermal and stress-strain state of a wedge-shaped model of ChS70 nickel alloy with heat-resisting thermal insulating coatings of Co-Cr-Al-Y composite, exposed to cyclic thermal action of a gas flow, is performed by the finite-element method. The data are obtained on the influence of processing factors and the thickness of the heat-shield layer upon the kinetics of the stress-strain state of the model material. The presence of a ceramic layer is found to result in a change in the cycle asymmetry toward tensile stresses and in the shift of the stress maximum to the region of lower temperatures.

  18. Fundamental studies on electron beam welding on heat-resistant superalloys for nuclear plants, (3)

    International Nuclear Information System (INIS)

    In this report, microcracks in the electron beam welds of the superalloys for nuclear plants were metallurgically investigated. Obtained conclusions can be summarized as follows; 1) The precipitates adjacent to the fusion line of Hastelloy X, Inconel 617 and Incoloy 807 which accompany microcracks change and melt clearly. On the other hand, those of Inconel 625 and SUS 316 in which microcracks never occur remain unchanged, and the precipitates remain nearly in the original condition in the case of Incoloy 800 which accompanies microcracks. 2) Main precipitates identified for every superalloy are M23C6 and M6C for Hastelloy X, M6C for Inconel 617, NbC and Ti(C,N) for Incoloy 807, NbC for Inconel 625, Ti(C,N) for Incoloy 800 and M23C6 for SUS 316. 3) The liquation of precipitates is considered to take place only when either melting temperature of precipitates or eutectic temperature between precipitates and matrix ? is lower than the temperature of matrix to start melting. 4) It is easily presumed that a microcrack will initiate at the melted precipitate at the grain boundary of the heat affected zone adjacent to the fusion line where the distribution of temperature, stress and strain is of peculiar characteristics. This distribution will be described in the following report in details. (author)

  19. Influence of pH on heat resistance of spores of Bacillus coagulans in buffer and homogenized foods.

    Science.gov (United States)

    Palop, A; Raso, J; Pagán, R; Condón, S; Sala, F J

    1999-02-18

    The influence of pH of heating menstruum (McIlvaine buffer) on the heat resistance of Bacillus coagulans spores has been investigated and compared with the heat resistance in homogenized tomato and asparagus at pH 7 and 4 at a wide range of temperatures. Spores were less heat resistant in all menstrua at acid pH. The magnitude of this effect was greatest at the lowest heating temperatures tested. z values in buffer increased from 8.9 degrees C at pH 7 to 10.5 degrees C at pH 4. pH of menstrua was the main influencing factor, but media composition also influenced heat resistance: at pH 7 heat resistance was similar in all menstrua (D111 degrees C = 1.6 min) but at pH 4 the heat resistance in homogenized foods (D111 degrees C = 0.26 min in tomato and D111 degrees C = 0.28 min in asparagus) was lower than in buffer (D111 degrees C = 0.49 min). The reduced influence of the acidification of media on the heat resistance of B. coagulans at higher temperatures should be taken into account when a rise in the temperature of treatment for canned vegetables is considered to shorten duration of heat processes. PMID:10100904

  20. Synthesis of heat-resistant SiC fiber by radiation processing

    International Nuclear Information System (INIS)

    The heat-resistant silicon carbide (SiC) fiber was formed from the precursor fiber of silicon containing organic polymer 'polycarbosilane (PCS)' by radiation curing technique. PCS fibers were irradiated in He atmosphere by 2MeV electron beam, then the fiber changed to non-melt fibers during the heat treatment for conversion from PCS fiber to SiC fiber. The SiC fibers, which contained less oxygen by the radiation curing of PCS fiber, showed high heat-resistance. The tensile strength and Young's modulus of SiC fiber containing oxygen of 0.4 % was 2.5 GPa and 280 GPa, respectively, after heat treatment at 1973 K (1700C) in Ar atmosphere, which is higher by 500 K than those of SiC fiber as 'Nicalon' which was formed from thermal oxidation curing of PCS fiber. (author)

  1. Does enhanced heat resistance of irradiated insects represent greater ability to adapt

    International Nuclear Information System (INIS)

    Previous work from this lab demonstrated that irradiated flour beetles (Tribolium) develop resistance to oxygen with similar kinetics: greater sensitivity for about 1 week, increasing resistance over the next week, and resistance persisting for 3-6 months. This is in contrast to the rapid development of heat resistance in yeast exposed to UV or ionizing radiation and to rapid induction of heat-stress proteins in E. coli exposed to UV or nalidixic acid. The authors' early work did not distinguish between intrinsic heat resistance and enhanced ability to adapt. They tried to resolve this problem by comparing response of irradiated and of control beetles to challenge at 450C with or without brief exposure to 410C just prior to challenge. Mean lethal exposure time at 450C was increased to about the same extent in both populations after 15 min at 410C, suggesting that irradiation increases insectors' intrinsic resistance to stress rather than their ability to adapt

  2. New candidate genes for heat resistance in Drosophila melanogaster are regulated by HSF

    OpenAIRE

    Jensen, Louise Toft; Nielsen, Morten Muhlig; Loeschcke, Volker

    2008-01-01

    The cellular heat stress response is well studied in Drosophila in respect to the role of heat shock proteins (Hsp). Hsps are molecular chaperones, highly expressed during and after exposure to numerous stress types. Hsps are all regulated by a common transcription factor, the heat shock factor (HSF), and it is known that HSF is controlling other, so far uncharacterised, heat-responsive genes. In this study, we investigate whether novel candidate genes for heat resistance, identified by micro...

  3. Injection Molded Optical Lens Using a Heat Resistant Thermoplastic Resin with Electron Beam Cross-Linking

    Science.gov (United States)

    Tomomi Sano,; Yoshitomo Iyoda,; Takayuki Shimazu,; Michiko Harumoto,; Akira Inoue,; Makoto Nakabayashi,; Hiroshi Ito,

    2010-05-01

    The poor heat resistant properties of a transparent thermoplastic resin was improved by electron beam irradiation cross-linking. A correcting aspheric lens for a 635-nm laser diode was fabricated using an injection molding machine, and was irradiated with an electron beam. The near field pattern (NFP), the far field pattern (FFP) at the focus position and the transmittance of the lens did not change after exposure to a 260 °C reflow process for 60 s.

  4. Using heat-resistant elastic fabric for boiler unit expansion pieces

    Energy Technology Data Exchange (ETDEWEB)

    Liseikin, I.D.; Gubanov, V.Y.; Kozlov, U.V.; Panchenko, V.F.; Pervova, A.I.; Postnikov, A.D.; Seregina, L.I.

    1980-01-01

    Results are given from test-bed and industrial research on an expansion piece made from a multi-layered element consisting of heat-resistant elastic fibers. Tests on the new expansion piece design (which is used to seal the joint in the region where the upper sections of the tubular air heater are connected to the convective shaft of the P-59 boiler) in a gas temperature range up to 400/sup 0/ centigrade demonstrated its efficiency and operational reliability.

  5. Technique for heat resistance test of samples brittle electric conducting materials with the use of electron beam heating

    Energy Technology Data Exchange (ETDEWEB)

    Popov, V.P.; Lanin, A.G.; Bochkov, N.A.

    1984-09-01

    A method of heat resistance tests under local heating by electron beam is considered for plane specimens of brittle current-conducting material. Heat flow is determined according to electron beam electrical parameters with an error +-10%. Simple analytical expressions are given for heat resistance criteria through heat flow and time to failure. The values of the first and the second heat resistance criteria are determined on ZrCsub(0.93) specimens and are equal to 65 degrees and 1.3x10/sup 3/ W/m at 50 deg C, 106 degrees and 2.6x18/sup 3/ W/m at 170 deg C, respectively.

  6. Change in the heat-resistance of sunflower plants under the local effect of soft X-rays

    International Nuclear Information System (INIS)

    The local effect of soft X-rays on the growth and heat-resistance of sunflower plants was studied. Irradiation of the main point of growth with doses of 27 and 36 Gr was found to raise the limit of heat-resistance of the plants by 2.5-3.0 deg C. This is apparently related to the accumulation of the dry mass of the leaves owing to the inhibited growth of the stem. A direct correlation was established between the heat-resistance of the plants and the content of firmly bound wat.er in the leaves

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

    Science.gov (United States)

    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

  8. Analysis on the heat-resisting property of high temperature process parts

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Hwan; Jung, Jae Hoo; Yoon, Ji Sup; Hong, Dong Hee; Park, Gi Yong [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2002-02-01

    To reduce the storage space of spent fuel used at the atomic power plants in the over the world, the uranium elements contained in the spent fuel is being extracted and effectively stored. For this, the spent fuel are oxidized deoxidized. In this study, it is produced conceptual design specification about the spent fuel management technology research and test facility for the spent fuel waste for spent fuel minimized. The first considered processes in the facility are the powdering and mixing process in the dry environment and the metal conversion process. Since these two processes are operated at the high temperature range, we have to consider heat-resisting designs for the devices. For the heat-resisting designs, we have searched and analyzed technical reference for material properties. Also, we have determined the temperature distribution condition of the devices based on experimental results. We have calculated thermal stress and strain of each devices by the commercial analysis software, I-DEAS. By using the results, we have analyzed design configurations of the point at issue by thermal effects, and suggested alternative design configurations. It is experimented for inspecting confidence rate of heat strain. Based on these results, it is produced necessary design specifications for heat-resisting design. 15 refs., 61 figs., 19 tabs. (Author)

  9. Heat resistance of Escherichia coli O157:H7 in apple juice.

    Science.gov (United States)

    Splittstoesser, D F; McLellan, M R; Churey, J J

    1996-03-01

    The objective was to determine the effect of cider composition on the heat resistance of Escherichia coli O157:H7. The average D52 value in a model Empire apple juice was 18 min with a z value of 4.8 degrees C. Increasing the Brix from 11.8 to 16.5 degrees had no effect on thermal resistance, while increasing L-malic acid from 0.2 to 0.8%, or reducing the pH from 4.4 to 3.6 sensitized the cells to heat. The greatest effect on heat resistance was afforded by the preservatives benzoic and sorbic acids: D50 values in ciders containing 1,000 mg/l were 5.2 min in the presence of sorbic acid and only 0.64 min in the presence of benzoic acid. Commercial apple juice concentrates yielded lower numbers of survivors than single-strength juices even though their higher sugar concentrations of about 46 degrees Brix increased heat resistance. PMID:10463437

  10. Crack growth in metallic alloys

    International Nuclear Information System (INIS)

    A potential drop method, based on the compensation concept is described; technical parameters and capability are discussed. Selected examples with metallic alloys for high temperature and heat resistant application demonstrate the applicability of the method for fatigue and creep crack growth investigations in the temperature range up to 1173 K and 1223 K, respectively. At room temperature and at 1173 K the results of the potential drop method are verified by optical means. (orig.) 891 IHOE/orig. 892 HIS

  11. Galvanic corrosion resistance of welded dissimilar nickel-base alloys

    International Nuclear Information System (INIS)

    A program for evaluating the corrosion resistance of various dissimilar welded nickel-base alloy combinations is outlined. Alloy combinations included ALLCORR, Hastelloy C-276, Inconel 72 and Inconel 690. The GTAW welding process involved both high and minimum heat in-put conditions. Samples were evaluated in the as-welded condition, as well as after having been aged at various condtions of time and temperature. These were judged to be most representative of process upset conditions which might be expected. Corrosion testing evaluated resistance to an oxidizing acid and a severe service environment in which the alloy combinations might be used. Mechanical properties are also discussed

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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-?K relation, da/dN-?J relation and da/dt-j relation were found to be appropreate for the three modes respectively. (author)

  15. Creep behaviour of hastelloy XR in simulated high-temperature gas-cooled reactor helium

    International Nuclear Information System (INIS)

    Creep tests of Hastelloy XR (a modified version of the conventional Hastelloy X) were carried out in simulated high-temperature gas-cooled reactor helium at 800, 900 and 1000degC. The test results up to about 50,000h showed no significant degradation in creep properties such as the rupture life, rupture ductility and the steady-state creep rate. The creep-rupture strength obtained through long-term tests was above the level corresponding to the design allowable creep-rupture stress of the High-Temperature Engineering Test Reactor. The values of the stress exponent were 4.5 to 5.7 when the stress dependence of the steady-state creep rate was expressed in terms of the Norton equation. Rupture lives could be estimated with sufficient accuracy using Larson-Miller parameter. Carbon analysis for ruptured specimens showed that carburization was limited to the region near the ruptured portion. The surface crack tips were blunted at the depth of 100 to 200?m from the specimen surface. Internally formed cracks were initiated at sites of precipitates at grain boundaries, growing nearly perpendicular to the stress axis. The electron probe microanalysis revealed that two precipitates, Mo-rich phase and Cr-rich phase, co-existed. (author)

  16. Ductility loss of neutron-irradiated hastelloy-X at elevated temperatures

    International Nuclear Information System (INIS)

    Ductility loss of neutron-irradiated Hastelloy-X at elevated temperatures was examined by post-irradiation slow tensile test. The results were analyzed as functions of test temperature, strain rate, thermal neutron fluence and the associated helium generation due to nuclear transmutation. In addition to the 10B(n, ?)7Li reaction, the contribution of helium generation due to the two-step reaction 58Ni(n, ?)59Ni(n, ?)56Fe at higher fluences was considered. Irradiations were made mostly at 600C, followed by high-temperature tensile tests; the effects of irradiation temperature were examined separately. The post-irradiation ductility generally decreased with temperature increase up to 10000C. Extrapolations of the results of irradiation at 600C gave the apparent fracture ductility values of 3.5% at 9000C and 1.5% at 10000C. Threshold thermal neutron fluences for the ductility loss were also predicted as 6 x 1016n/cm2 at 9000C and 10000C, respectively. Ductility loss was increased when the irradiation was made at temperatures equivalent to the tensile test conditions. The results are discussed in connection with the application of Hastelloy-X for control rod sheath material in high temperature gas-cooled reactor. (author)

  17. Heat treatment of incoloy 800 and Hastelloy X for boiler tubes

    International Nuclear Information System (INIS)

    A recent tendency in steam generated by boilers for industrial use is that temperature and pressure values are getting higher than ever, and so the research and development of valves for such use are now in progress. We lately succeeded in getting an order from a customer for the manufacture of a boiler to be used for the above-mentioned research and development, which produces for the purpose 350 kg/cm2 and 6500C steam at the outlet of the final superheater. In manufacturing the above boiler, Incoloy 800 and Hastelloy X tubes, which had not been used for boilers before, were adopted for the first time for the high temperature and pressure part of the boiler (the final superheater). Although there were no processing standards officially approved and regulated concerning the materials, the solution heat treatment after welding and bending performance were considered necessary, and the microstructure and hardness tests were conducted to select the optimum heat treatment condition. As a result of our study, we have found that when Incoloy 800 and Hastelloy X are solution heat treated at 1,1250C for 2 minutes per 1 mm thickness of steel pipe wall, satisfactory results can be attained. (author)

  18. Characterization of Hot Deformation Behavior of Hastelloy C-276 Using Constitutive Equation and Processing Map

    Science.gov (United States)

    Zhang, Chi; Zhang, Liwen; Shen, Wenfei; Li, Mengfei; Gu, Sendong

    2015-01-01

    In order to clarify the microstructural evolution and workability of Hastelloy C-276 during hot forming to get excellent mechanical properties, the hot deformation behavior of this superalloy is characterized. The cylindrical specimens were isothermal compressed in the temperature range of 1000-1200 °C and strain rate range of 0.001-5 s-1 on a Gleeble 1500 thermal-mechanical simulator. The flow curves and microstructural investigation indicates that dynamic recrystallization is the prime softening mechanism at the evaluated deformation conditions. The constitutive equation was presented as a function of the deformation temperature, strain rate, and strain, and the deformation activation energy was about 450 kJ/mol. The processing maps based on dynamic materials model at the strains of 0.2, 0.4, 0.6, 0.8, and 1.0 were established, and the processing map at 1.0 strain shows good correspondence to the microstructural observation. The domains in processing map in which the efficiency of power dissipation (?) is higher than 0.25 are corresponding to sufficient dynamic recyrstallization phenomenon, which are suggested to be the optimum working areas for Hastelloy C-276.

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

    International Nuclear Information System (INIS)

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

  20. Studies of thermal-cycle endurance of heat resistant materials under asymmetric thermomechanical loading

    International Nuclear Information System (INIS)

    Results of experimental investigation of thermal-cycle endurance of heat resistant materials under conditions of asymmetric thermo-mechanical loading are presented. Using the maximum-likelyhood fit statistical evaluation of the parameters of logarithmically normal distribution of the sample endurance are obtained with an account of the parameter dependence on the level of stresses. A mathematical model of endurance based on the approximation of diagrams of limiting stresses in the case of asymmetric thermo-mechanical loading with the equation of inclined ellipse is suggested. Comparison of the calculated endurance, obtained with an aid of the model with the experiment results is made

  1. Estimation of work capacity of welded mounting joints of pipelines of heat resisting steel

    International Nuclear Information System (INIS)

    The analysis of a work capacity of circular welds made for the Dsub(y)850 pipeline connection with high pressure vessels of heat resisting steel of the 15Kh1NMFA type has been carried out on the base of test results with small samples and real units. Welds were performed using the manual electric arc welding without the following heat treatment. It has been shown that residual stresses in such welds do not produce an essential effect on the resistance of weld metal and heat affected zone on the formation and developments of cracks

  2. Study on new concept for an LMFBR lining system using heat resistant and sodium compatible concrete

    International Nuclear Information System (INIS)

    A new concept of an LMFBR lining system using heat resistant and sodium compatible concrete has been developed. The objective was to reduce the cost and construction period for the conventional steel lining system used to protect the secondary building's floor concrete from leaked sodium. Screening tests and small-scale liner model tests have been carried out to select a material candidate for two kinds of lining system. The sodium pouring test with medium-scale lining floor model was carried out to evaluate the structure integrity. A hydrogen generation test from concrete was accomplished to predict the sodium leakage consequences analytically. (author)

  3. Comparison of strength characteristics of heat resisting materials under active tension and constant load

    International Nuclear Information System (INIS)

    Strength characteristics of heat resisting materials (steel 12Kh1MF) obtained during short-term active tension with constant deformation rate are shown to be used for plotting curves of a long-term strength on small temporal basis. For this purpose a graph was suggested to be marked with the points whose coordinates corresponded to a value of a spontaneously measured active deformation time to failure of a sample with the respective equivalent strains determined from deformation curves by a calculation method

  4. Using flame spraying to increase heat resistance of slit radiant recuperator

    International Nuclear Information System (INIS)

    The possibility is shown to use ferrosilicium coating produced by flame spraying as a protective layer of the inner cylinder of slit radiation recuperator. Ferrosilicium spraying procedures and optimal particle sizes are determined; heat resistance of samples of the St. 3 sp carbon steel with and without coating as well as that of Kh23N18 steel samples are studied. It is shown that it is advantageous to use coated St. 3 steel for recuperator fabrication instead of the Kh23N18 stainless steel

  5. Effect of partly recrystallized strucre on the 15Kh1M1F steel heat resistance

    International Nuclear Information System (INIS)

    Effect of partly recrystallized structure on heat resistance properties of the 15Kh1M1F steel and their stability in the process of prolonged high-temperature loading is investigated. The steel has been studied in two structural states: bainite and ferrite-carbide ones. It is established that the 15Kh1M1F steel with partly recrystallized structure is characterized by lower stability and lower limit of prolonged strength than the steel tempered at technological temperatures. At that, prolonged plasticity also decreases, especially it concerns the relative narrowing

  6. Change in the system free energy of 9Cr heat resistant ferritic steels with creep time

    International Nuclear Information System (INIS)

    Microstructural state of metallic materials can be expressed by the system free energy, and the estimation of the system free energy is useful for the damage analysis of the materials. In this study, change in the system free energy of 9Cr heat resistant ferritic steels is estimated with creep time on the basis of Thermo-Carlo calculation as well as a series of experiments such as X-ray diffraction analysis, chemical analysis using extracted residues, etc., and the change with creep time is expressed quantitatively by introducing the relaxation time into the system free energy. (author)

  7. A study on application of rare earth metals in heat resistant steels

    International Nuclear Information System (INIS)

    The influence of rare earth (RE) on the oxidation, high temperature strength and hot-ductility of Cr-Si, Cr-Ni and Cr-Ni -N steels has been studied in order to tap the potentialities of RE in heat resistant steels. Experimental steels were melted in an induction furnace. The amount of metallic La or Ce additions were controlled in the range of 0.01-0.10%. In order to keep nearly the same basic composition of the steel, every heat was poured into two ingots, one with RE, another without

  8. Heat resistance and local structure of FeCl2-absorbed crosslinked poly(?-glutamic acid)

    International Nuclear Information System (INIS)

    Fiber of Japanese food natto (Bacillus subtilis) is known to be superabsorbent poly(?-glutamic acid) (PGA). NaCl particles precipitate in FeCl2-absorbed crosslinked PGA when heated at crystallization temperature of 320 deg C for 10 to 60 min. After heat treatment the Moessbauer spectrum of FeCl2-crosslinked PGA consists of a quadrupole doublet due to FeCl2 x 2H2O. The Moessbauer spectrum of anhydrous FeCl2 reagent heated under the same condition shows an intense sextet due to ?-Fe2O3. These results prove that the superabsorbent polymer, crosslinked PGA, has higher heat resistance. (author)

  9. Resistance to corrosion fatigue fracture in heat resistant steels and their welded joints

    International Nuclear Information System (INIS)

    Experimental data on cyclic crack resistance of heat-resistant steels and their welded joints employed for production of the reactor bodies are for the first time generalized and systematized. The formula is suggested accounting for surface and inner defects to calculate the fatigue crack growth in the process of operation. This formula for surface defects regards also the effect of the corrosion factor. Mechanisms of the reactor water effect on the fatigue crack growth rate are considered as well as a combined effect of radiation and corrosive medium on this characteristic

  10. Material design data of 2.25Cr-1Mo steel and hastelloy-x for the experimental multi-purpose very-high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    The preliminary structural design guidelines for the experimental multi-purpose very-high temperature gas-cooled reactor have recently been prepared. The components of the primary system operating at temperatures of creep dominant range are grouped in those of pressure and temperature boundaries respectively. In the material selection, 2 1/4Cr-1Mo steel is chosen for the former and Hastelloy-X for the latter taking into account of material properties at operating temperature. Deriving from the literature in the field, material design data of the alloys are established in design forms such as Sy, So, Sm, St, 100% of minimum stress to rupture, design fatigue curves, isochronous stress-strain curves, creep-fatigue interaction damage factor and so on, which are defined in ASME Code Section III, Code Case 1592. (auth.)

  11. Improved corrosion resistance of Hastelloy G-30 in nitric/hydrofluoric acid solutions by welding with Inconel 72 weld wire

    International Nuclear Information System (INIS)

    When welding Hastelloy G-30, secondary phases form in the weld metal. These phases cause the weld metal to be preferentially attacked in nitric acid (HN03) solutions contaminated with minor amounts of hydrofluoric acid (HF). A post weld solution anneal and water quench is necessary to assure that these phases redissolve into the solid. When a post weld solution anneal and water quench is not feasible, improved corrosion resistance can be obtained by welding with INCO 72 weld wire. When welding Hastelloy G-30 with INCO 72, there can be a region at the weldmetal/base-metal interface that does not benefit from the INCO 72 weld wire. This region consists of melted and resolidified Hastelloy G-30. This unmixed zone can be preferentially attacked in HN03 solutions contaminated with minor amounts of HF. Long term corrosion immersion tests have shown that the rate of attack at the weld-metal/base-metal interface can be as high as 50 mpy. Welding techniques that increase the mixing of the melted Hastelloy G-30 with the INCO 72 weld wire can reduce the interface corrosion rate

  12. Practical handbook of stainless steels and nickel alloys

    Energy Technology Data Exchange (ETDEWEB)

    Lamb, S. [ed.

    1999-07-01

    This new handbook is an up-to-date technical guide to the grades, properties, fabrication characteristics, and applications of stainless steels and nickel alloys. The individual chapters were written by industry experts and focus on the key properties and alloy characteristics important in material selection and specification as well as the practical factors that influence the development and application of these materials. The contents include: alloy grades and their welding and fabrication characteristics and their application; monel metal; iron-based and nickel-based alloys; ferritic, austenitic, superaustenitic, and martensitic stainless steels; hastelloys; alloys 20, G, and 825; AOD and new refining technology; duplex stainless steels; 6-Mo alloys; corrosion-resistant castings; specification cross-reference tables; trade names; hardness conversions; list of common abbreviations.

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

    International Nuclear Information System (INIS)

    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)

  14. Concurrent emergence of multidrug resistance and heat resistance by CTX-M-15-encoding conjugative plasmids in Klebsiella pneumoniae.

    Science.gov (United States)

    Bojer, Martin S; Hammerum, Anette M; Jørgensen, Steffen L; Hansen, Frank; Olsen, Stefan S; Krogfelt, Karen A; Struve, Carsten

    2012-09-01

    A plasmid-encoded ClpK protein was recently identified as a predictor of a heat-resistant phenotype in the opportunistic pathogen Klebsiella pneumoniae. This study was undertaken to evaluate the presence of the clpK gene in extended-spectrum ?-lactamase (ESBL)-producing K. pneumoniae and to assess the probable co-transfer of multi-resistance with the heat resistance phenotype. A Danish collection of 80 ESBL-producing K. pneumoniae bloodstream infection isolates was screened for clpK by colony hybridization. Nineteen isolates (24%) were positive for clpK; some of them representing major clones identified in Denmark. Among these, nine isolates belonged to a single K. pneumoniae CTX-M-15 clone with sequence type (ST)16 exhibiting a heat-resistant phenotype. This clone has a multi-hospital occurrence and has also been detected outside Denmark. Horizontal co-transfer of multiple antibiotic resistances, including the CTX-M-15 resistance determinant, and the heat resistance phenotype was observed. Thus, the clpK gene is harbored by different ESBL-producing K. pneumoniae isolates including a clone of ST16 internationally spread. The co-localization of clpK on transferable ESBL-encoding plasmids allowing co-dissemination of multiple drug resistance with bacterial heat resistance is a highly interesting phenomenon that may further complicate the prevention of spreading of certain successful clones of multi-resistant K. pneumoniae. PMID:22882258

  15. Internal pressure creep behaviors for Hastelloy X cylinder with EB butt welded joint

    International Nuclear Information System (INIS)

    Creep tests under internal-pressure on circumferentially EB-welded cylinders made of Hastelloy X were carried out for the investigation of structural behaviors of welded components in elevated temperature environment. Penetration cracks were not observed at base metal zone but at weld metal zone. EB welded zone of the cylinder showed the comparable creep ductility as compared with the non-welded cylinder. The creep rupture strength of EB-welded cylinders was lower than that of non-welded cylinders, but superior to TIG-welded cylinders. The rupture time ratio of EB-welded cylinders to non-welded cylinders was smaller than the ratio of EB weld metal to base metal obtained from uni-axial tests. The decrease in rupture strength under internal pressure is considered due to the difference in creep rates between EB weld metal and base metal. (author)

  16. Thermomechanical cyclic hardening behavior of Hastelloy-X. M.S. Thesis

    Science.gov (United States)

    Bartolotta, P. A.

    1985-01-01

    Experimental evidence of thermomechanical history dependence on the cyclic hardening behavior of a representative combustor liner material Hastelloy-X is presented, along with a discussion about the relevant concept of thermomechanical path dependence. Based on the experimental results, a discussion is given on the inadequacy of formulating nonisothermal constitutive equations solely on the basis of isothermal testing. Finally, the essence of a mathematical representation of thermoviscoplasticity is presented that qualitatively accounts for the observed hereditary behavior. This is achieved by formulating the scaler evolutionary equation in an established viscoplastic theory to reflect thermomechanical path dependence. Although the necessary nonisothermal tests for further quantifying the thermoviscoplastic model have been identified, such data are not yet available.

  17. The effect of weldability of alloy JBK-75 with various filler metal wire additions

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, C.L.

    1991-04-01

    The purpose of this study was to investigate the compositional factors that affect the weldability of alloy JBK-75. This study was accomplished by using a variety of different commercial filler materials to systematically evaluate the weldability in the compositional range surrounding alloy JBK-75. The experimental design included varestraint testing, scanning electron microscopy, and phase diagram analysis. The varestraint testing demonstrated that the weldability of alloy JBK-75 could be improved with the use of other commercially available filler metals. The best improvement to weldability of alloy JBK-75 was with type 308L stainless steel and Hastelloy W filler metals. Adequate improvement to the weldability of alloy JBK-75 was obtained when utilizing types 309L and 310 stainless steel filler metals. Alloy 320LR, alloy 650 (NiCrFe-1), Incoloy 901, and Inconel 92 (NiCrFe-6) filler metals only marginally improved the weldability of alloy JBK-75. 59 refs., 27 figs., 24 tabs.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    International Nuclear Information System (INIS)

    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

  20. Preparation of heat-resistant silicon carbide fiber from polycarbosilane fiber cured by electron beam irradiation

    International Nuclear Information System (INIS)

    Heat-resistant silicon carbide (SiC) fiber was synthesized by the heat treatment of polycarbosilane (PCS) fiber with electron beam irradiation curing. PCS fiber was irradiated up to 10 - 15 MGy by 2 MeV electron beam under He gas atmosphere, then the fiber was well cured. The SiC fiber obtained from the radiation cured PCS fiber contained lesser oxygen comparing with the Si-C-O fiber 'Nicalon', which was synthesized by thermal oxidation curing of PCS fiber and contained oxygen of about 10 wt%. The thermal decomposition temperature of Si-C-O fiber increased by decrease of oxygen content in the fiber. For the very low oxygen content (0.35 wt%) fiber, the tensile strength and the Young's modulus was 2.5 GPa and 250 GPa, respectively, after heat treatment at 1,973 K. Applying this radiation curing technique, long size of SiC fiber (several 100g) was synthesized. (author)

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

    Directory of Open Access Journals (Sweden)

    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.

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

    International Nuclear Information System (INIS)

    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

  3. Study of heat resistance of chromium-nickel-manganese ferritic-austenitic steels

    International Nuclear Information System (INIS)

    Effect of chemical composition of austenitic-ferritic steels on their scale resistance at 800, 900 and 1000 deg C was studied. Investigation was conducted for steel of 16 casts, differing with respect to nickel, manganese, as well as chromium contents. Certain steel casts had molybdenum additions. Considerable decrease of heat resistance of chromium-nickel ferritic-austenitic steels with 18-23% Cr and variable nickel contents from 0.2 up to 6.03% in the air in 800-1000 deg C temperature range was noted when manganese content was increased. Positive chromium effect on scale resistance with increase of its concentration in steel from 18 up to 23% is manifested only at certain manganese contents

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

    International Nuclear Information System (INIS)

    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

  5. Measurement of the transmitted and reflected capture gamma rays for heat resistant concrete shield

    International Nuclear Information System (INIS)

    The experimental measurements of the transmitted and the reflected (albedo) components of the capture secondary gamma rays, arising from interaction of reactor neutrons with heat resistant concrete shields were carried out. This new type of concrete is prepared from Egyptian ilmenite-limonite ores and has a density 3.44 gm/cm3. The measurements were performed using a collimated beam of reactor neutrons emitted from one of the horizontal channels of the ET-RR-1 reactor. A single stilbene crystal scintillator applying zero crossover technique for differentiation between gamma and neutron pulses was utilized. The measured instrument spectra were transformed to energy spectra. From the measurements it is evident that the albedo capture gamma rays are very small in comparison with the total or the transmitted capture gamma rays. (author)

  6. Single crystal rhenium-containing nickel alloys for turbine engine blades

    International Nuclear Information System (INIS)

    The fundamental potentials for designing single crystal nickel-base carbon-free alloys doped with rhenium up to 9-10% and exhibiting a high castability are established. It is shown that a 9%-Re alloy surpasses the III generation alloys in the properties. In so doing, the attained level of heat resistance is high enough to warrant using high rhenium content. The phase stability of high-rhenium alloys is provided by the limitation of IV group elements (Cr, Mo, W) in alloy composition to prevent TCP-phase formation. A high content of refractory elements provides an alloy stability to bulk recrystallization on high-temperature homogenizing annealing

  7. Segregation in welded nickel-base alloys

    International Nuclear Information System (INIS)

    Segregation effects have been investigated in nickel-base alloys monel 400, inconel 625, hastelloy C-276 and incoloy 825, test welded under controlled conditions. Deviations from the normal composition have been observed to varying extents in the welded zone of these alloys. Least effect of this type occurred in Monel 400 where the content of Cu increased in some of the areas. Enhancement of Al and Ti has been found over large areas in the other alloys which has been attributed to the formation of low melting slag. Another common feature is the segregation of Cr, Fe or Ti, most likely in the form of carbides. Enrichment of Al, Ti, Nb, Mb, Mo, etc., to different amounts in some of the areas of these materials is in- terpretted in terms of the formation of gamma prime precipitates or of Laves phases. (author)

  8. Nitrogen hardening of creep-resistant G-NiCr28W alloy

    OpenAIRE

    Pirowski, Z.; Wodnicki, J.; Gwiz?dz?, A.

    2010-01-01

    In the group of creep-resistant materials, most important are heat-resistant nickel-based alloys. The G-NiCr28W alloy subject to detailed examinations was observed to have two different austenite-like phases. In the interdendritic spaces of alloy matrix, the presence of another phase, also characterised by paramagnetic properties, was detected. Inside this interdendritic phase, local areas of a lamellar structure, composed of both of the above mentioned phases, were present. Nitrogen treatmen...

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

    International Nuclear Information System (INIS)

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen Lingen [Postgraduate School, Naval University of Engineering, Wuhan 430033 (China)]. E-mail: lgchenna@yahoo.com; Zhu Xiaoqin [Postgraduate School, Naval University of Engineering, Wuhan 430033 (China); Jiangsu Technical Normal College, Changzhou 223001 (China); Sun Fengrui [Postgraduate School, Naval University of Engineering, Wuhan 430033 (China); Wu Chih [Mechanical Engineering Department, US Naval Academy Annapolis, MD 21402 (United States)

    2006-06-15

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Lingen; Zhu, Xiaoqin; Sun, Fengrui [Postgraduate School, Naval University of Engineering, Wuhan 430033 (China); Wu, Chih [Mechanical Engineering Department, US Naval Academy Annapolis, MD 21402 (United States)

    2006-06-15

    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. (author)

  12. Long-term creep properties of hastelloy XR in simulated high-temperature gas-cooled reactor helium

    International Nuclear Information System (INIS)

    Creep tests of Hastelloy XR (a modified version of the conventional Hastelloy X) were carried out in simulated high-temperature gas-cooled reactor (HTGR) helium at 800, 900 and 1,000degC. The test results up to about 50,000 h showed no significant degradation in creep properties. The creep-rupture strength obtained through long-term tests was above the level corresponding to the design allowable creep-rupture stress of the High-Temperature Engineering Test Reactor. The values of the stress exponent were 4.5 to 5.7 when the stress dependence of the steady-state creep rate was expressed in terms of the Norton equation. It is judged that dominant creep process is dislocation creep. Rupture lives could be estimated with sufficient accuracy using Larson-Miller parameter. Carburization during creep in simulated HTGR helium did not degrade creep properties of Hastelloy XR. Internally formed cracks were initiated at sites of precipitates at grain boundaries, growing nearly perpendicular to the stress axis. Two phases, Cr-rich carbide and Mo-rich carbide, co-existed in specimens after long-term creep tests. (author)

  13. Hot hardness measurements on heat-resistant cast steels by the UCI process. [UCI = Ultrasonic Contact Impedance]. Warmhaertemessungen an hitzebestaendigen Gussstaehlen nach dem UCI-Verfahren

    Energy Technology Data Exchange (ETDEWEB)

    Halim, A.; Schiller, J. (Krautkraemer GmbH und Co., Huerth (Germany)); Schmitz, H.P.; Deilmann, M.; Dahl, W. (RWTH Aachen (Germany). Inst. fuer Eisenhuettenkunde)

    1991-01-01

    Heat-restistant cast materials are used in industry in furnace construction. These materials are exposed to temperatures above 1000deg C. At these temperatures they must also be restistant to high mechanical stresses. As the knowledge of material behaviour and the properties at high ambient temperatures is essential, test processes and equipment must be developed, which permit test at such a temperature. A MICRODUR 2 hardness testing equipment from the firm of Krautkraemer working on the UCI process was used for hardness measurements. Samples of heat-resistant cast steels with the material numbers 1.4837 and 1.4848 and of alloy No. 2.4879 were examined at temperatures between room temperature 1000deg C. The material behaviour at high temperatures could be characterized from the UCI hardness values determined. In order to examine the behaviour of the material after a certain period and temperature of operation, some samples were stored at T=600deg C and for periods of 10 to 100 hours. The hardness/temperature curves were then determined. (orig./MM).

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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 ? and ? 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

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

    Directory of Open Access Journals (Sweden)

    Shmotin Yuriy

    2014-01-01

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

  17. Fabrication process of heat-resisting electrically conductive bodies made of borides and boron nitride

    International Nuclear Information System (INIS)

    The object of the present invention is the fabrication of bodies containing less than 0.5 wt.% oxygen in a single, easily accomplished process step. According to the invention, 50-70 wt.% of an electrically conducting, heat resisting boride, e.g. zirconium boride, titanium boride and 30-50 wt.% boron nitride containing boroxide, are mixed to a uniform dispersion and then pressed at 1700-20000C under a pressure of 35 to 140 kp/cm2. The hot-pressed piece is immersed in a suitable solvent to reduce the boroxide content which either dissolves the boroxide or forms soluable conversion products with it. This treatment is carried out until the weight remains constant. The solutions used according to the invention contain water (preferably with addition of small quantities of strong acid), low primary, secondary and tertiary alcohols (aliphatic as well as aromatic). Following the solvent treatment, the compact is dried by heating and sintered without pressure in a innert atmosphere preferably at 1800-21000C. The sintered bodies are characterized by high density, good thermal resistance, small heat expansion coefficients, a low irreversible thermal expansion nonsensitiveness to moisture and excellent resistance to thermal shocks. Due to the latter property, the material in recommended for the manufacture of crucibles, particularly suitable for fast evaporation of metals (can be used to temperatures > 22000C). 4 manufacturing examples000C). 4 manufacturing examples. (IHOE) 891 IHOE

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

    DEFF Research Database (Denmark)

    Samson, R.A.; Houbraken, J.

    2009-01-01

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

  19. The effect of creep on magnetic domain structure of heat resistant steels

    Science.gov (United States)

    Zhang, S. Z.; Tu, S. T.

    2013-04-01

    The magnetic domain and magnetic properties of heat resistant steels including 10CrMo910, P91 and 23CrMoNiWV88 are investigated in the present work. The magnetic properties characterized by magnetic hysteresis loop of the three materials under 500-600°C are measured by vibrating sample magnetometer (VSM). The magnetic domain structure of as-received and crept specimens is observed by magnetic force microscope (MFM). The magnetic domain of ferrite phase change from initial stripe pattern to maze pattern during creep. The black and white fringes and stripe-like pattern have also been found in the P91 and 23CrMoNiWV88 specimens, respectively. The experimental results reveal that the magnetic domain structure is strongly influenced by microstructures with different distributions of the carbides. It is shown that the coercivity and remanence of each material although has a remarkable decrease at 500-600°C especially for P91 almost 64% decrease, it's still the same magnitude as the one at room temperature. All the short-term crept specimens with different creep damage have a linear increase in coercivity and remanence comparing to the as-received 10CrMo910 specimens. These results indicate that it should be possible to develop an in-situ monitoring technology for creep damage based on magnetism measurement.

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

    International Nuclear Information System (INIS)

    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 ?-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.)

  1. Superconductivity mediated by a soft phonon mode: specific heat, resistivity, thermal expansion and magnetization of YB6

    CERN Document Server

    Lortz, R; Tutsch, U; Abe, S; Meingast, C; Popovich, P; Knaffo, W; Shitsevalova, N; Paderno, Y B; Junod, A; Paderno, Yu. B.

    2006-01-01

    The superconductor YB6 has the second highest critical temperature Tc among the boride family MBn. We report measurements of the specific heat, resistivity, magnetic susceptibility and thermal expansion from 2 to 300 K, using a single crystal with Tc = 7.2 K. The superconducting gap is characteristic of medium-strong coupling. The specific heat, resistivity and expansivity curves are deconvolved to yield approximations of the phonon density of states, the spectral electron-phonon scattering function and the phonon density of states weighted by the frequency-dependent Grueneisen parameter respectively. Lattice vibrations extend to high frequencies >100 meV, but a dominant Einstein-like mode at ~8 meV, associated with the vibrations of yttrium ions in oversized boron cages, appears to provide most of the superconducting coupling and gives rise to an unusual temperature behavior of several observable quantities. A surface critical field Hc3 is also observed.

  2. An all-fiber, polarized, core-pumped heat-resistant thulium-doped master oscillator power amplifier

    International Nuclear Information System (INIS)

    We present an all-fiber, polarized, core-pumped heat-resistant thulium-doped master oscillator power amplifier (MOPA) system. The laser operated at a wavelength of 1926.7 nm with a spectral linewidth of less than 70 pm. For a repetition rate of 100 kHz, a maximum average power of 750 mW with a slope efficiency of 48.8% and pulse duration of 41 ns was achieved. Even without active cooling, no observable thermal effects occurred when the laser was operated at room temperature. To the best of our knowledge, this core-pumped heat-resistant MOPA configuration is the first reported in the 2 ?m region. (paper)

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

    DEFF Research Database (Denmark)

    de Jong, Aarieke E I; van Asselt, Esther D

    2012-01-01

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

  4. The Heat-Resistant Agglutinin Family Includes a Novel Adhesin from Enteroaggregative Escherichia coli Strain 60A?†

    OpenAIRE

    Mancini, Justin; Weckselblatt, Brooke; Chung, Yoonjie K.; Durante, Julia C.; Andelman, Steven; Glaubman, Jessica; Dorff, Justin D.; Bhargava, Samhita; Lijek, Rebeccah S.; Unger, Katherine P.; Okeke, Iruka N.

    2011-01-01

    Heat-resistant agglutinin 1 (Hra1) is an accessory colonization factor of enteroaggregative Escherichia coli (EAEC) strain 042. Tia, a close homolog of Hra1, is an invasin and adhesin that has been described in enterotoxigenic E. coli. We devised a PCR-restriction fragment length polymorphism screen for the associated genes and found that they occur among 55 (36.7%) of the enteroaggregative E. coli isolates screened, as well as lower proportions of enterotoxigenic, enteropathogenic, enterohem...

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

    OpenAIRE

    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. Assessment of Heat Resistance of Bacterial Spores from Food Product Isolates by Fluorescence Monitoring of Dipicolinic Acid Release

    OpenAIRE

    Kort, Remco; O Brien, Andrea C.; Stokkum, Ivo H. M.; Oomes, Suus J. C. M.; Crielaard, Wim; Hellingwerf, Klaas J.; Brul, Stanley

    2005-01-01

    This study is aimed at the development and application of a convenient and rapid optical assay to monitor the wet-heat resistance of bacterial endospores occurring in food samples. We tested the feasibility of measuring the release of the abundant spore component dipicolinic acid (DPA) as a probe for heat inactivation. Spores were isolated from the laboratory type strain Bacillus subtilis 168 and from two food product isolates, Bacillus subtilis A163 and Bacillus sporothermodurans IC4. Spores...

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

    International Nuclear Information System (INIS)

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

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

    International Nuclear Information System (INIS)

    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)

  9. Characterization of the behaviour of heat-resistant steels under cyclic creep conditions. Final report

    International Nuclear Information System (INIS)

    The creep behaviour of characteristic, heat-resistant steels under conditions of rectangular, cyclic creep loading can be derived from the standard creep behaviour under constant creep by applying the modified life-fraction rule. The relative life as the characteristic constant of this rule can be determined by means of a factor set composed of a cycle factor, a materials factor, and a temperature factor. The cycle factor depends on the variation of stress or temperature, or both, and on the value and extent of changes in loading. The materials factor depends on the steel type and the temperature factor is determined by the temperature level exceeding a steel-type-specific temperature close to the lowest service temperatures. It is possible to extend the factor set by an additional strain factor describing the relative tensile yield strength up to a given plastic strain. The product of the materials factor, temperature factor and, if applicable, the strain factor has to be interpolated towards the value of one for the case of transition to constant creep. By means of scatter band evaluations, average time-to-rupture curves and limiting creep stress curves have been measured for the steels subjected to cyclic loads, and after fitting to standard values, these curves have been incorporated into a LARA user program that can calculate expected values of the limiting creep time and the time-to-rupture under conditions of rectangular, cyclic loading, based on the modified lr, cyclic loading, based on the modified life-fraction rule and the factor set approach. (orig.)

  10. Thermonuclear reactor wall, method of manufacturing them, heat resistant shielding member for thermonuclear reactor wall and thermonuclear reactor

    International Nuclear Information System (INIS)

    Since carbon fibers have been oriented in the direction of a plate surface in usual heat resistant shielding plates for a thermonuclear reactor, heat conductivity along the direction of the plate thickness is not sufficient and temperature rises greatly at the surface of the heat resistant shielding plate due to the thermal load from plasmas. Accordingly, evaporization loss is remarkable and the working life as the reactor wall is short. In view of the above, the carbon fibers in heat resistant shielding members are oriented so as to intersect the boundary between the shielding members and support members for fixing them. As a production method, carbon fiber-woven clothes are impregnated with pitches and laminated, pitches are further impregnated into gaps formed upon pressure-sintering and then they are finally sintered at a temperature higher than 2800degC to apply graphitization. Thus, since it is possible to increase the heat conductivity along the direction of the plate thickness than the value along the direction of the plate surface and suppress the temperature rise at the heat receiving surface, the cooling effect can be improved to reduce the surface abrasion loss due to evaporization. (N.H.)

  11. 17th colloquium on long-time behaviour of heat-resistant steels and high-temperature materials

    International Nuclear Information System (INIS)

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

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

    Directory of Open Access Journals (Sweden)

    Yastreb T.O.

    2012-08-01

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

  13. Investigation on multi-element Ni-Cr-Mo-Cu alloying layer by double glow plasma alloying technique

    International Nuclear Information System (INIS)

    This paper describes an investigation of double glow surface alloying of low-carbon steel with Hastelloy C-2000 nickel-based surperalloy. Emphasis is placed on the effect of the source electrode voltage, cathode voltage, working pressure and parallel distance between source electrode and cathode on the chemical composition and physical qualities of surface alloying layer. The results show that the total content of alloy elements, thickness of alloying layer and absorbing alloy element rate have closely related with technological parameters. The combination of SEM and XRD is used to investigate morphology and structure of the multi-element Ni-Cr-Mo-Cu surface alloying layer. The thermodynamic calculation was performed to predict the mole fraction of phase in the alloying layer as function of temperature. The calculated results is in agreement with the observation of microstructure of alloying layer. The corrosion experimental results indicated that the corrosion resistance of alloying layer formed on the stainless steel was super to that of alloying layer formed on the low-carbon steel

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

    Science.gov (United States)

    Calle, Luz

    1990-01-01

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

  15. Phase equilibrium in niobium base alloys containing titanium, zirconium, and hafnium nitrides

    International Nuclear Information System (INIS)

    Determined are the phase equilibria and the structure of ternary niobium-base alloys with nitrogen and titanium, zirconium and hafnium. The Nb-ZrN, Nb-TiN, Nb-HfN sections has the eutectic character and constitute quasibinary sections of the corresponding ternary state diagrams. The eutectic compositions and the melting temperatures of quasibinary eutectics are determined. The isothermal sections of ternary Nb-N-Ti(Zr,Hf) diagrams are proposed. Thermodynamic compatibility of phases, relatively high melting temperature and the character of structure of quasibinary eutectic niobium alloys with refractory titanium, zirconium, and hafnium mononitrides testify the promising application of these alloys as heat-resistant materials. A considerable heat-resistance of the eutectic alloys of the Nb-ZrN system is shown

  16. Magnesium Cermets and Magnesium-Beryllium Alloys

    International Nuclear Information System (INIS)

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

  17. Production and testing of the rolled ring with the regulated structure from the foreign nickel alloys

    International Nuclear Information System (INIS)

    With the aim of meeting the required combination of mechanical properties for rolled rings of nickel base alloys Waspaloy, Haynes-188 and Hastelloy-X, newly developed regimes of hot working and heat treatments are proposed. Both seamless and welded ring-like rolling billets are used to study the influence of conditions of alloy deformation on grain structure uniformity. It is established that hot working of the billet at a temperature below 1000 deg C allows one to meet rigid requirements to microstructure, to assure stable high mechanical properties and to prevent crack propagation

  18. Lanthanum, yttrium, titanium, zirconium and boron effect on high-tem erature properties of chromium-nicel alloys in different media

    International Nuclear Information System (INIS)

    To further improve the properties of chromium-nickel steels with a high chromium content the effect of small additions of yttrium, lanthanum, titanium and zirconium (up to 1%) and boron (up to 0.01%) on oxidation kinetics, composition and structure of oxide films formed on 40Ni-60Cr alloy during oxidation in the air and during interaction with products of natural gas burning and products of mazut burning, containing approximately 3% S, has been studied. It is shown that alloying the 40Ni-60Cr alloy with low additions of boron, lanthanum, yttrium, titanium and zirconium decreases considerably the rate of its oxidation in the air, especially at high temperatures. Alloying with rare earths is the most efficient one. Heat resistance of chromium-nickel alloys in products of natural gas burning is higher than in the air. Corrosion resistance of chromium-nickel alloys with high chromium content in products of high-sulphur mazut burning is higher than that of industrial heat resisting alloys. Alloying the 40Ni-60Cr alloy with small additions of lanthanum or titanium increases its corrosion resistance 5-15%. Low additions of boron, lanthanum, yttrium, titanium and zirconium increase significantly plasticity of the 40Ni-60Cr alloy without considerable decrease of its heat resistance

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

    International Nuclear Information System (INIS)

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

  20. Kinetics of chromium evaporation from heat-resisting steel under reduced pressure

    Directory of Open Access Journals (Sweden)

    C. Kolmasiak

    2012-07-01

    Full Text Available This paper describes a kinetic analysis of the process of chromium evaporation from ferrous alloys smelted under reduced pressure. The study discussed comprised determination of the liquid phase mass transfer coefficient as well as the value of the constant evaporation rate. By applying these values as well as the values of the overall mass transfer coefficient estimated based on the relevant experimental data, the fractions of resistance of the individual process stages were established.

  1. Summary of studies on hot corrosion of iron-based alloys by sodium sulfate in O2/SO2/SO3 environment

    OpenAIRE

    Zhang, Yunshu; Wu, Weitao

    1993-01-01

    Iron base heat-resistant alloys are widely used in high temperature environments, especially in civil and industrial boilers and other combustors. This type of alloys was found to undergo hot corrosion when covered with a sulfate deposit. Recent studies of sulfate-deposit-induced hot corrosion of iron-base alloys are selectively reviewed in this paper. Emphasis is placed on studies of the hot corrosion occurring at relatively low temperatures, concerning the thermodynamics of the formation of...

  2. The effect of alloying on the ordering processes in near-alpha titanium alloys

    International Nuclear Information System (INIS)

    The substructure of near-alpha Ti–Al–Sn–Zr–Mo–Si alloys containing up to 12.5 at% aluminum was studied by transmission electron microscopy (TEM). It was shown that long-range order sections are formed at aging temperatures up to 500 °C in alloys, high in aluminum, and the ordered phase is formed by the nucleation and growth mechanism at 700 °C aging temperatures. Causes of changing the phase transformation mechanism have been discussed, and the relationship between the structure and properties of alloys, depending on modes of heat treatment has been analyzed. Also the influence of aluminides and silicides precipitation on the mechanical alloy properties after aging was examined. It was shown that the aluminide formation led to a slight hardening and a significant viscosity decrease. The silicide particles formation reduced the heat resistance properties, due to the depletion of the solid solution by silicon

  3. Directed change of composition and morphology of primary carbide phases in cast nickel alloys

    International Nuclear Information System (INIS)

    To study the effect of small additions of hafnium and zirconium on the composition and morphology of carbides, and the distribution of alloying elements, the nickel alloy doped with 19% Cr, 5% Mo, 8% Fe, 4.1% (Al+Ti), 0.05% C has been selected. Carbide composition and the distribution of alloying elements has been determined using the microroentgenospectral method. The doping of nickel heat resistant alloys with small additions of such strong carbide forming elements as hafnium and zirconium is shown to produce a manifold positive effect on the structure and properties of alloys. Hafnium and zirconium shift carbide reactions during eutectic crystallization towards the formation of more stable carbide phases; increase the melting point of eutectic alloy constituents, disperse carbide phases thus contributing to the decrease of grain size difference in alloy, lower the chemical microheterogeneity of main alloying elements

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

    Science.gov (United States)

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

    2007-08-21

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

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

    Science.gov (United States)

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

    2015-02-01

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

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

    International Nuclear Information System (INIS)

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

  7. Contemporary tendency of alloyed steel development

    International Nuclear Information System (INIS)

    Perspectives of developing alloyed steels based on structure improvement and increase of technologic and service properties are considered. It is shown that for economy of the alloying elements it is necessary: to amplify works on steel microalloying; to develop the processes of obtaining steel pure by impurities in mass quantities (powder metallurgy, remelting processes, out-of-furnace refining); to arrange wide production of heat treated steel; to expand theoretical works and arsenal of industrial technical means providing use of strain hardening as a method for increasing mechanical properties of wide purpose steel; to develop methods of effective use of production wastes of alloyed steels fabrication and ferroalloyed production; to essentially expand application of corrosion-resistant heat-resistant and wear- resistant coatings

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

    International Nuclear Information System (INIS)

    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. Strain-heat hardening of maraging alloys

    International Nuclear Information System (INIS)

    Investigation data on the ageing of martensite in the Fe-Ni-Co base alloys containing 10-14% Mo are presented. Heating temperature effect upon solubility in austenite of the exceessive intermetallide phase Fe7Mo6 is studied. Optimum temperature of the heating ensuring high ductility after quenching is determined. The structure, shape and distribution of precipitates after the ageing are determined. It is established that combination of plastic deformation with subsequent ageing permits to obtain Fe-Ni-Co-Mo heat resistant microwire with deltasub(u)=300-400 kg/mmsup(2) and satisfactory ductility

  10. On supercoaling of nickel alloy granules during recrystallization

    International Nuclear Information System (INIS)

    On the example of heat resisting nickel base alloy of ZhS6K shown is a possibility of a considerable supercooling of the metal bath in the whole volume of the . grain, that leads to the alloy structure grinding at the following recrystallization. At the scanning electron microscope grain surfaces are investigated and the regularity of the size change of dendrite branches is shown. It is found that separate grains for parts of some grains possess considerably finer dendrite structure. It can be more reliably explained by preliminary supercooling of the metal bath in the whole volume of such a grain

  11. Corrosion behavior of Ni-Cr-base commercial alloys in flowing Ar-42.6%O{sub 2}-14.7%Br{sub 2} gas mixture at 700 C

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.; Tsujikawa, S. [Tokyo Univ. (Japan). Dept. of Metall.

    1997-07-01

    Corrosion behavior of Ni-Cr-Base commercial alloys has been investigated in an argon-42.6% oxygen-14.7% bromine gas mixture at 700 C which was one of the environments encountered in the UT-3 thermochemical water decomposition reaction process to produce hydrogen. The test alloys were Inconel 600, Hastelloy C-276, Inconel 625, and Nimonic 80A. Two-dimensional thermodynamic phase stability diagrams were constructed for nickel, chromium, iron, tungsten, cobalt, titanium, and aluminium to predict the condensed corrosion products that are stable with respect to the representative alloying elements when the alloy is exposed to the argon-42.6% oxygen-14.7% bromine gas mixture at 700 C. The oxides were thermodynamically stable phases with respect to the corresponding metals. Post-reaction treatment of test alloys included discontinuous mass-change measurements, scanning electron microscopy (SEM), electron probe micro-analysis (EPMA) for morphological and compositional investigation of the corrosion products, and the X-ray diffraction (XRD) for phase identification. XRD identified oxides and spinels as corrosion products but low-melting metal bromides were also detected for all alloys with deleterious effects on high-temperature properties of these alloys during exposure to the environment. The poor corrosion resistance of Inconel 600 and Hastelloy C-276 was mainly caused by the cracking and spalling of iron and nickel-rich oxides and further growth of various metal bromides beneath the oxide scale following prolonged exposure. Inconel 625 and Nimonic 80A alloys performed better than Inconel 600 and Hastelloy C-276, mainly because of their aluminium alloying element and lower iron content. (orig.) 13 refs.

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

    Science.gov (United States)

    Shi, Zimu; Cao, Jianbo; Han, Fusheng

    2014-04-01

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

  13. Effect of thymol in heating and recovery media on the isothermal and non-isothermal heat resistance of Bacillus spores.

    Science.gov (United States)

    Esteban, Maria-Dolores; Conesa, Raquel; Huertas, Juan-Pablo; Palop, Alfredo

    2015-06-01

    Members of the genus Bacillus include important food-borne pathogen and spoilage microorganisms for food industry. Essential oils are natural products extracted from herbs and spices, which can be used as natural preservatives in many foods because of their antibacterial, antifungal, antioxidant and anti-carcinogenic properties. The aim of this research was to explore the effect of the addition of different concentrations of thymol to the heating and recovery media on the thermal resistance of spores of Bacillus cereus, Bacillus licheniformis and Bacillus subtilis at different temperatures. While the heat resistance was hardly reduced when thymol was present in the heating medium, the effect in the recovery medium was greater, reducing the D100°C values down to one third for B. subtilis and B. cereus when 0.5 mM thymol was added. This effect was dose dependent and was also observed at other heating temperatures. PMID:25790989

  14. Heat-resistant martensitic steels with 9 to 12 percent chronium as core components for fast reactors

    International Nuclear Information System (INIS)

    Heat-resisting martensitic 12% chromium steels are considered as alternative materials for application as fuel-element components such as wrappers in the liquid sodium cooled fast breeder reactor. This type of steel appears to have certain important advantages in comparison with austenitic stainless steels as far as the response to heavy neutron irradiation is concerned. The published information on the swelling and in-pile creep behaviour and on the influence of irradiation on tensile, creep and impact properties has been reviewed. Very promising results are available as to void swelling resistance and creep strength and ductility. On the other hand, data on the effect of high neutron doses on the impact strength, on the irradiation creep behaviour and on the structural stability are still missing so that the potential of this type of steel cannot yet finally be judged. (orig.)

  15. Fetal calf sera can distort cell-based luminescent proteasome assays through heat-resistant chymotrypsin-like activity.

    Science.gov (United States)

    Dettmer, Susan; Theile, Dirk; Seckinger, Anja; Burhenne, Jürgen; Weiss, Johanna

    2015-02-15

    Luminescence-based proteasome activity assays use specific substrates that are supposed to be cleaved by cellular proteasome activity leading to luciferase substrates. Usually, control wells containing cell culture medium supplemented with antibiotics and fetal calf serum are used as background. Using the Proteasome-Glo chymotrypsin-like cell-based assay from Promega, we show here that fetal calf sera from different manufacturers contain heat-resistant, bortezomib-inhibitable, chymotrypsin-like activities that can interfere with proteasome activity assays. These data strongly recommend the use of pure phosphate-buffered saline (PBS) or serum-free medium during proteasome activity assays to diminish background luminescence and, thus, to obtain reliable results. PMID:25447494

  16. Microstructural Evolution and Mechanical Properties of Short-Term Thermally Exposed 9/12Cr Heat-Resistant Steels

    Science.gov (United States)

    Wang, Wei; Yan, Wei; Sha, Wei; Shan, Yiyin; Yang, Ke

    2012-11-01

    The microstructural evolution during short-term (up to 3000 hours) thermal exposure of three 9/12Cr heat-resistant steels was studied, as well as the mechanical properties after exposure. The tempered martensitic lath structure, as well as the precipitation of carbide and MX type carbonitrides in the steel matrix, was stable after 3000 hours of exposure at 873 K (600 °C). A microstructure observation showed that during the short-term thermal exposure process, the change of mechanical properties was caused mainly by the formation and growth of Laves-phase precipitates in the steels. On thermal exposure, with an increase of cobalt and tungsten contents, cobalt could promote the segregation of tungsten along the martensite lath to form Laves phase, and a large size and high density of Laves-phase precipitates along the grain boundaries could lead to the brittle intergranular fracture of the steels.

  17. Creep rupture properties of Hastelloy-X and Incoloy-800H in a simulated HTGR helium environment containing high levels of moisture

    International Nuclear Information System (INIS)

    Creep rupture tests on Incoloy-800H and Hastelloy-X have been carried out in a simulated steamcycle high-temperature gas-cooled reactor helium environment containing a high level of moisture. For the maximum test time of 16 000 h, the creep rupture behavior of Incoloy-800H in the helium environment was not significantly different from that in air. Hastelloy-X showed a slightly lower rupture life in helium in comparison with standard air tests. Surface cracks initiated at the grain boundaries penetrating surface and cavities formed at the grain boundary triple points have been identified as major fracture mechanisms in both environments. Oxidation was the only gas/metal interaction observed in the helium environment

  18. The effect of ultrasonic machining on the mechanical properties of nickel base alloys

    International Nuclear Information System (INIS)

    The effect of ultra-sound upon the mechanical properties of nickel base heat- and corrosion-resistant alloys was studied on cast and deformed metal. The tests were carried out for static tension, twisting and impact strength at temperatures of hot mechanical working (900 to 1200 deg C). The investigations indicate that a finer structure of the multi-component nicel base alloy obtained through ultrasonic treatment of a solidifying metal results in the improvement of the plasticity of the cast and the deformed metal. The ultrasonic treatment improved the heat-resistance of the EP109, EP220, EP881 alloys by 10 to 15 %

  19. A low dose pre-irradiation induces radio- and heat-resistance via HDM2 and NO radicals, and is associated with p53 functioning

    Science.gov (United States)

    Takahashi, A.; Ohnishi, T.

    2009-04-01

    The aim of this work was to clarify the effect of low dose pre-irradiation on radio- and heat-sensitivity. Wild-type (wt) p53 and mutated (m) p53 cells derived from the human lung cancer H1299 cell line were used. The parental H1299 cell line is p53-null. Cellular sensitivities were determined with a colony-forming assay. When wtp53 cells were exposed to a low dose X-irradiation, induction of radio- and heat-resistance was observed only in the absence of RITA (an inhibitor of p53-HDM2 interactions), aminoguanidine (an iNOS inhibitor) and c-PTIO (an NO radical scavenger). In contrast, the induced radio- and heat-resistance was not observed under similar conditions in mp53 cells. Moreover, heat-resistance as well as radio-resistance developed when wtp53 cells were treated with ISDN (an NO generating agent) alone. These findings suggest that NO radicals are an initiator of radio- and heat-resistance, and function through the activation of HDM2 and the depression of p53 accumulation.

  20. Reel-to-reel electropolishing of Ni alloy tapes for IBAD template

    International Nuclear Information System (INIS)

    Ni alloy tape is electropolished to be used as a metal substrate for fabrication of IBAD (ion-Beam Assisted Deposition)-MgO texture template fur HTS coated conductor. Electropolishing is needed to obtain a very smooth surface of Ni alloy tape because the in-plane texture of templates is sensitive to the roughness of metal substrate. The critical current of YBCO coated conductor depends on the texture of YBCO that depends on the texture of the IBAD MgO layer. And so the smoothness of the metal substrate is directly related to the superconducting properties of the coated conductor. In this study, we have prepared a reel-to-reel electropolishing apparatus to polish the Ni alloy tapes for IBAD. Various electropolishing conditions were investigated to improve the surface roughness. Hastelloy tape is continuously electropolished with high polishing current density (0.5 - 2 A/cm2) and fast processing time (1 - 3 min). Polished hastelloy tapes have surface roughness(RMS) of below 1 nm on a 5 X 5 ??2 from AFM and SEM.

  1. Influence of phase transformations in cobalt alloys on diffusion and mechanical properties

    International Nuclear Information System (INIS)

    It is shown that cobalt alloys involve a wide pretransitional temperature range with anomalous increase in mean square of atomic displacement, diffusion mobility and ductility. Comparison of the behaviour of cobalt-base binary alloys and heat-resistant commercial alloy of the MAR-M322 type in a wide temperature range suggests that a lower long-term strength at temperatures under 900 deg C in the MAR-M322 alloys is associated with the polymorphic transformation of the lattice FCC into the lattice HCP in the matrix. It is shown that doping of the optimal amount of nickel into the MAR-M322 alloy (10 wt% at the expense of cobalt) enhances the endurance of the alloy at 800-900 deg C

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

    International Nuclear Information System (INIS)

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

  3. Comparative corrosion resistance of some high-nickel, chromium-molybdenum alloys

    International Nuclear Information System (INIS)

    The comparative corrosion resistance of alloy C-276 (UNS N10276), alloy 625 (UNS N06625), Hastelloy C-22 (UNS N06022), and ALLCORR (UNS N06110) was studied in sodium chloride-ferric chloride solutions, and nitric, hydrochloric, formic, and sulfuric acids, some with additives such as HF. Butt-welded coupons were used to determine the corrosion characteristics of weldments. In addition to weight loss measurements, crevice and pitting attack were evaluated. For a complex chemical facility to vitrify high-level radioactive wastes, a corrosion study was conducted to select materials of construction for handling the various process streams, several of which were unusually corrosive. Two high-nickel, chromium-molybdenum alloys, C-276 (UNS N10276) and 625 (UNS N06625), were acceptable for much of the processing

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

    International Nuclear Information System (INIS)

    A surface severe plastic deformation (S2PD) method has been applied to bulk specimens of HASTELLOY C-2000 alloy, a nickel-base alloy. The mechanical properties of the processed C-2000 alloy were determined via tensile tests and Vickers hardness measurements, whereas the microstructure was characterized using scanning electron microscopy, transmission electron microscopy, and X-ray diffractometry. The improved tensile strength was related to the nanostructure at the surface region, the residual compressive stresses, and the work-hardened surface layer, all of which resulted from the S2PD process. To understand the contributions of these three factors, finite element modeling was performed. It was found that the improved tensile strength could be interpreted based on the contributions of nano-grains, residual stresses, and work hardening

  5. Corrosion behavior of C-276 alloy in supercritical water at 650 degree C/25 MPa

    International Nuclear Information System (INIS)

    The corrosion behavior of nickel-base alloy Hastelloy C-276 was investigated in supercritical water (SCW) at 650 degree C/25 MPa. SEM, EDS, GIXRD and XPS were used to analyze the corrosion morphology, structure and element distribution of oxide film. The results show that the corrosion process of C-276 alloy at 650 degree C/25 MPa in SCW is mainly dissolution of Ni. Since it can not form a uniform and complete oxide film, the alloy in SCW is not well placed to corrosion resistance. The dual-layer oxide film structure which is formed on C-276 is rich in Cr but poor in Ni, Mo. The outer layer consisting of loose and large grains Ni(OH)2 and NiO agrees with dissolution and precipitation mechanism, while the growth of the Cr2O3 inner layer is the result of water through the porous oxides. (authors)

  6. Fracture toughness of a X alloy under static load

    International Nuclear Information System (INIS)

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

  7. Structural thermal stability of Ni3Al-base alloy and its use for blades of small-size gas-turbine engine

    International Nuclear Information System (INIS)

    The comparative evaluation of stability of the working blades structures of the TVD-20 engine turbine, produced from the experimental alloy VKNA-4UMono and the serial alloy ZhS64 is carried out after 4800 operating cycles on the engine. It is shown that replacement of the industrial serial nickel alloys of the ZhS64-type by the intermetallide alloy VKNA-4UMono provides for the possibility of increasing the permissible operating temperatures on the working and nozzle blades of the aviation gas-turbine engines by 50-100 Deg C, decreasing their mass, improving their heat resistance and increasing their service life by 2-3 times

  8. Electrode coating effect on composition and properties of nickel-chromium deposited metal alloyed with titanium

    International Nuclear Information System (INIS)

    The effect of coating composition with liquid glass as a bond on composition and properties of metal, weld surfaced by electrodes, containing titanium, on Ni heat-resistant alloy, is investigated. Impossibility of producing electrodes with high transformation of titanium with coatings, having liquid glass as a bond, is shown experimentally. It is connected with low resistance and plasticity of surfaced weld metal due to its impurity with silicon and titanium oxides

  9. ZrO2-base fritted refractory material for lining induction precision alloy furnaces

    International Nuclear Information System (INIS)

    ZrO2-base refractory was utilized for fabrication of fritted crucibles for precision alloy fusion. The fitness of the material was estimated from the data on the degree of the metal penetration into the wall of the refractory crucible and from the wetting angle of the fritted refractory samples. An elevated heat resistance of the lining and a high quality of the synthesized metal are pointed out

  10. Cyclic creep behaviour of heat-resistant steels under intermittent stress and in the tension/compression area

    International Nuclear Information System (INIS)

    The creep behaviour of heat-resistant steels under rectangular cyclic creep stress can be derived from the modified service life share rule from the normal creep behaviour under constant stress. The relative service life as a constant in this rule can be described by a factor concept with two cycle factors; a material factor, a strain factor and a temperature factor. This concept can be expanded in the tensile stress area, so that it can be used for stress changes R = ?min/?max in the range R = 1 to 01 ie: from constant stress to intermittent stress. The effect of an additionally inserted limited compression phase can also be included by a further factor. To reproduce the creep behaviour in the tension/compression area, constitutive equations are required, which describe the creep speed relative to stress, temperature and internal variables. They supply a very general description of the material, but are more complicated to produce and to use. Such a set of equations was developed and successfully used for a 12% CrMOV steel at 600 C. (orig.)

  11. Molecular methods used to estimate thermal inactivation of a prototype human norovirus: more heat resistant than previously believed?

    Science.gov (United States)

    Escudero-Abarca, B I; Rawsthorne, H; Goulter, R M; Suh, S H; Jaykus, L A

    2014-08-01

    Two molecular-based methods for estimating capsid integrity as a proxy for virus infectivity were used to produce thermal inactivation profiles of Snow Mountain virus (SMV), a prototype human norovirus (HuNoV). Monodispersed virus suspensions were exposed to 77, 80, 82 and 85 °C for various times, pre-treated with either propidium monoazide (PMA) or RNase, and subjected to RNA isolation followed by RT-qPCR amplification. D-values were 25.6 ± 2.8, 3.1 ± 0.1, 0.7 ± 0.04 and 0.2 ± 0.07 min at 77, 80, 82 and 85 °C, respectively for PMA-treated SMV; and 16.4 ± 0.4, 3.9 ± 0.2 0.9 ± 0.3 and 0.12 ± 0.00 min at 77, 80, 82 and 85 °C, respectively for RNase-treated SMV. Corresponding zD values were 3.80 °C and 3.71 °C for PMA and RNase-treated virus, respectively. Electron microscopy data applied to heat-treated virus-like particles supported this relatively high degree of thermal resistance. The data suggest that SMV is more heat resistant than common cultivable HuNoV surrogates. Standardized thermal inactivation methods (such as milk pasteurization) may not be stringent enough to eliminate this virus and perhaps other HuNoV. PMID:24750817

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

    International Nuclear Information System (INIS)

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

  13. Development of cold isostatic pressing graphite module for a heat-resistant lower hybrid current drive antenna

    International Nuclear Information System (INIS)

    Development of a plasma facing module using Cold Isostatic Pressing Graphite (CIPG) was successfully achieved for use in driving a heat-resistant Lower Hybrid Current Drive (LHCD) antenna. A thin stainless film (10 ?m), a molybdenum film (10 ?m), and a copper film (50 ?m) were overlaid on the CIPG materials, the CIPG surfaces were successfully coated with the Cu-layer by diffusion bonding method. This module whose length is 206 mm, has four waveguides, and a water cooling channel. High rf-power long pulse operations with water cooling were successfully tested up to 250 kW (125 MW/m2)/700 s, a stationary temperature and vacuum pressure was performed. But the maximum rf transmission power was limited to 47 MW/m2 for a plasma facing module using Carbon Fiber Composite (CFC) due to poor Cu-plating, a power density large by more than a factor 2.5 was achieved with the CIPG module. The rf power density which meets the requirement of the rf electric field of 5 kV/cm for a design of the LHCD antenna in International Thermonuclear Experimental Reactor (ITER) was successfully performed

  14. Preparation and characterization of the heat-resistant UV curable waterborne polyurethane coating modified by bisphenol A

    Directory of Open Access Journals (Sweden)

    2010-11-01

    Full Text Available In this study, the modified ultraviolet (UV curable waterborne polyurethane was obtained from isophorone diisocyanate (IPDI, polyethylene glycol (PEG, MW=600, ?,?-dimethylol propionic acid (DMPA, hydroxyethyl acrylate (HEA and bisphenol A. The rigid moiety was introduced into the main chain of polyurethane to improve its heat-resistance. The copolymer structure was confirmed by Fourier transform infrared spectroscopy (FT-IR. Thermal property and UV curable behavior of the coatings were investigated. The glass transition temperature (Tg of the modified film was determined by differential scanning calorimetry (DSC. Thermal gravimetric analysis (TGA was employed to investigate the thermal stability of the modified film. The results show that the average particle diameters increased from 69.25 to 95.12 µm as the content of bisphenol A increased from 0.00 to 9.25%. The optimum bisphenol A dosage was 7.23% (wt%, the Tg of the modified film increased by 7.07°C and 5% weight-loss temperature (233°C increased by 14°C. The optimum irradiation time was 10–20 minutes after the coatings being painted on an armor plate at room temperature and initiator dosage was 5% (wt% of the latex.

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

    Science.gov (United States)

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

    2014-02-01

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

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

    Directory of Open Access Journals (Sweden)

    Miroshnichenko N.N.

    2011-05-01

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

  17. Precipitation behavior and martensite lath coarsening during tempering of T/P92 ferritic heat-resistant steel

    Science.gov (United States)

    Xu, Lin-qing; Zhang, Dan-tian; Liu, Yong-chang; Ning, Bao-qun; Qiao, Zhi-xia; Yan, Ze-sheng; Li, Hui-jun

    2014-05-01

    Tempering is an important process for T/P92 ferritic heat-resistant steel from the viewpoint of microstructure control, as it facilitates the formation of final tempered martensite under serving conditions. In this study, we have gained deeper insights on the mechanism underlying the microstructural evolution during tempering treatment, including the precipitation of carbides and the coarsening of martensite laths, as systematically analyzed by optical microscopy, transmission electron microscopy, and high-resolution transmission electron microscopy. The chemical composition of the precipitates was analyzed using energy dispersive X-ray spectroscopy. Results indicate the formation of M3C (cementite) precipitates under normalized conditions. However, they tend to dissolve within a short time of tempering, owing to their low thermal stability. This phenomenon was substantiated by X-ray diffraction analysis. Besides, we could observe the precipitation of fine carbonitrides (MX) along the dislocations. The mechanism of carbon diffusion controlled growth of M23C6 can be expressed by the Zener's equation. The movement of Y-junctions was determined to be the fundamental mechanism underlying the martensite lath coarsening process. Vickers hardness was estimated to determine their mechanical properties. Based on the comprehensive analysis of both the micro-structural evolution and hardness variation, the process of tempering can be separated into three steps.

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

    International Nuclear Information System (INIS)

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

  19. Research on preparation of Al-Fe-V-Si alloy enhanced by in-situ TiC particles

    Energy Technology Data Exchange (ETDEWEB)

    Baohong Zhu; Yong' an Zhang; Baiqing Xiong; Hongwei Liu; Likai Shi [National Engineering and Technology Research Center for Nonferrous MMCs, General Research Inst. for Nonferrous Metals, Beijing, BJ (China)

    2005-07-01

    Heat-resistant Al-Fe-V-Si aluminum alloys enhanced by in-situ TiC particles have been prepared by spray forming process with suitable process parameters. Research results show that the microstructure of as-deposited alloy is fine and homogeneous. In-situ TiC particles prevent the unsteady phases from coming into being. On the other hand, the TiC particles increase the volume fraction of heat-resistant phases. So the mechanical properties of the enhanced alloy by in-situ TiC particles are better than that of Al-Fe-V-Si alloy without TiC particles. The hot extrusion temperature is also an important parameter to understand. Under the permission, it is better to extrude the alloy at lower temperature. The tensile strength of the alloy without TiC particles is about 435 MPa at room temperature and is about 204 MPa at 350 C. However, when the alloy is enhanced by in-situ TiC particles, the strength of alloy is about 482 MPa at room temperature and is about 224 MPa at 350 C temperature. (orig.)

  20. Effect of Mg-Zn-Nd spherical quasi-crystals on microstructure and mechanical properties of ZK60 alloy

    OpenAIRE

    Zhang Jinshan; Wang Xing,; Zhang Zhaoguang

    2011-01-01

    To improve the strength, toughness, heat-resistance and deformability of magnesium alloy, the microstructure and mechanical properties of ZK60 alloy strengthened by Mg-Zn-Nd spherical quasi-crystal phase (I-phase) particles were investigated. Mg40Zn55Nd5 (I-phase) particles in addition to ?-Mg, MgZn phase and MgZn2 phases can be obtained in ZK60-based composites under normal casting condition by the addition of quasi-crystal containing Mg-Zn-Nd master alloy. The experimental results show tha...

  1. Carbon corrosion of alloys at high temperature

    Scientific Electronic Library Online (English)

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

    2013-02-01

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

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

    International Nuclear Information System (INIS)

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

  3. Glucono-delta-lactone and citric acid as acidulants for lowering the heat resistance of Clostridium sporogenes PA 3679 in HTST working conditions.

    Science.gov (United States)

    Silla Santos, M H; Torres Zarzo, J

    1995-04-01

    The heat resistance of Clostridium sporogenes PA 3679 spores has been studied to establish the influence of acidification with glucono-delta-lactone (GDL) and citric acid on the thermal resistance parameters (DT and z) of this microorganism and to compare their effect with phosphate buffer and natural asparagus as reference substrates. A reduction in DT values was observed in asparagus purée as the acidification level increased with both acidulants although this effect was more evident at the lower treatment temperatures studied (121-127 degrees C). Citric acid was more effective for reducing the heat resistance of spores than GDL at all of the temperatures. The reduction in pH diminished the value of the z parameter, although it was necessary to lower the pH to 4.5 to obtain a significant reduction. PMID:7547150

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

    International Nuclear Information System (INIS)

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

  5. Effect of impurities on the proneness to temper embrittlement of heat resistant Cr-Mo-V steel

    International Nuclear Information System (INIS)

    The authors investigated the effect of most alloying elements which are traditionaly regarded as dangerous in low-alloy structural steels--sulfur, phosphorus, copper, arsenic, antimony, tin--on the proneness to temper embrittlement of steel 25Kh1M1F which is used for making large all-forged rotors of fixed and transport medium-pressure steam turbines. On the basis of the obtained results it may be concluded that from among the investigated alloying elements only phosphorus and antimony have a statistically significant effect on the proneness of fine-grained steel 25Kh1M1F to temper embrittlement, and the embrittling effect of phosphorus is much stronger than the embrittling effect of antimony

  6. Chemistry of glass-ceramic to metal bonding for header applications. I. Effect of treatments on Inconel 718 and Hastelloy C-276 metallic surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, D P; Craven, S M; Schneider, R E; Moddeman, W E; Brohard, D W

    1984-02-02

    Auger electron spectroscopy and depth Auger profiling were used to study the surfaces of Inconel 718 and Hastelloy C-276. The metal surfaces were processed in the same manner as is presently being used in the manufacturing of glass-ceramic headers. At each step in the process, samples were studied with Auger spectroscopy to determine their resultant elemental surface composition and film thickness. In addition, the effect of a final plasma cleaning operation on the metal surface was examined. The results show that the type and concentration of surface species and the thickness of the surface oxides are dependent on the processing technique.

  7. The heat-resistant agglutinin family includes a novel adhesin from enteroaggregative Escherichia coli strain 60A.

    Science.gov (United States)

    Mancini, Justin; Weckselblatt, Brooke; Chung, Yoonjie K; Durante, Julia C; Andelman, Steven; Glaubman, Jessica; Dorff, Justin D; Bhargava, Samhita; Lijek, Rebeccah S; Unger, Katherine P; Okeke, Iruka N

    2011-09-01

    Heat-resistant agglutinin 1 (Hra1) is an accessory colonization factor of enteroaggregative Escherichia coli (EAEC) strain 042. Tia, a close homolog of Hra1, is an invasin and adhesin that has been described in enterotoxigenic E. coli. We devised a PCR-restriction fragment length polymorphism screen for the associated genes and found that they occur among 55 (36.7%) of the enteroaggregative E. coli isolates screened, as well as lower proportions of enterotoxigenic, enteropathogenic, enterohemorrhagic, and commensal E. coli isolates. Overall, 25%, 8%, and 3% of 150 EAEC strains harbored hra1 alone, tia alone, or both genes, respectively. One EAEC isolate, 60A, produced an amplicon with a unique restriction profile, distinct from those of hra1 and tia. We cloned and sequenced the full-length agglutinin gene from strain 60A and have designated it hra2. The hra2 gene was not detected in any of 257 diarrheagenic E. coli isolates in our collection but is present in the genome of Salmonella enterica serovar Heidelberg strain SL476. The cloned hra2 gene from strain 60A, which encodes a predicted amino acid sequence that is 64% identical to that of Hra1 and 68% identical to that of Tia, was sufficient to confer adherence on E. coli K-12. We constructed an hra2 deletion mutant of EAEC strain 60A. The mutant was deficient in adherence but not autoaggregation or invasion, pointing to a functional distinction from the autoagglutinin Hra1 and the Tia invasin. Hra1, Tia, and the novel accessory adhesin Hra2 are members of a family of integral outer membrane proteins that confer different colonization-associated phenotypes. PMID:21764925

  8. Neuroprotection by scorpion venom heat resistant peptide in 6-hydroxydopamine rat model of early-stage Parkinson's disease.

    Science.gov (United States)

    Yin, Sheng-Ming; Zhao, Dan; Yu, De-Qin; Li, Sheng-Long; An, Dong; Peng, Yan; Xu, Hong; Sun, Yi-Ping; Wang, Dong-Mei; Zhao, Jie; Zhang, Wan-Qin

    2014-12-25

    Neuroprotective effect of scorpion venom on Parkinson's disease (PD) has already been reported. The present study was aimed to investigate whether scorpion venom heat resistant peptide (SVHRP) could attenuate ultrastructural abnormalities in mitochondria and oxidative stress in midbrain neurons of early-stage PD model. The early-stage PD model was established by injecting 6-hydroxydopamine (6-OHDA) (20 ?g/3 ?L normal saline with 0.1% ascorbic acid) into the striatum of Sprague Dawley (SD) rats unilaterally. The rats were intraperitoneally administered with SVHRP (0.05 mg/kg per day) or vehicle (saline) for 1 week. Two weeks after 6-OHDA treatment, the rats received behavior tests for validation of model. Three weeks after 6-OHDA injection, the immunoreactivity of dopaminergic neurons were detected by immunohistochemistry staining, and the ultrastructure of neuronal mitochondria in midbrain was observed by electron microscope. In the meantime, the activities of monoamine oxidase-B (MAO-B), superoxide dismutase (SOD) and content of malondialdehyde (MDA) in the mitochondria of the midbrain neurons, as well as the inhibitory ability of hydroxyl free radical and the antioxidant ability in the serum, were measured by corresponding kits. The results showed that 6-OHDA reduced the optical density of dopaminergic neurons, induced damage of mitochondrial ultrastructure of midbrain neurons, decreased SOD activity, increased MAO-B activity and MDA content, and reduced the antioxidant ability of the serum. SVHRP significantly reversed the previous harmful effects of 6-OHDA in early-stage PD model. These findings indicate that SVHRP may contribute to neuroprotection by preventing biochemical and ultrastructure damage changes which occur during early-stage PD. PMID:25516514

  9. The effect of ethylenediaminetetraacetic acid on heat resistance and recovery of Clostridium sporogenes PA 3679 spores treated in HTST conditions.

    Science.gov (United States)

    Silla Santos, M H; Torres Zarzo, J

    1997-03-01

    The effect of ethylenediaminetetraacetic acid (EDTA) on the heat resistance of Clostridium sporogenes PA 3679 spores was studied. EDTA was added to heating substrates and recovery media in order to establish which stage of the heat treatment registered the greatest EDTA activity. The heating substrates assayed were phosphate buffer (pH 7.0) and white asparagus purée, at natural pH (5.8) and acidified with citric acid and glucono-delta-lactone (GDL) to pH 5.5, 5.0 and 4.5. Recovery of survivors was carried out in MPA3679A medium in various conditions of acidification with citric and GDL (250 and 500 ppm), at pH 7.5 6.5 and 6.0. The results show greater activity of EDTA on spores when it was applied in recovery of heat injured spores, than during heating. The strongest influence of EDTA during heating was found in phosphate buffer (pH 7.0), with the effect being most evident at 121 and 126 degrees C, and in asparagus purée, at 121 degrees C and pH 5.8 rather than acidified. In recovery, the inhibiting activity of EDTA was more evident in spores subjected to more severe heat treatment, either by increasing the exposure time or by raising the temperature to 130 or 135 degrees C. The pH level of the recovery medium also affected the antimicrobial activity of EDTA, which had a greater inhibiting effect at pH 7.5 than at lower pH levels (6.5, 6.0). PMID:9039574

  10. Combined Effect of Co and W on Deformation Resistance of 12Cr Heat-Resistant Steel for USC Steam Turbines

    Science.gov (United States)

    Cui, Huiran; Sun, Feng; Chen, Ke; Wu, Jiansheng

    2011-12-01

    12Cr heat-resistant steels with different concentrations of Co and W, with Mo equivalent (Mo + 1/2W) fixed at 1.6 wt.%, were prepared by arc-melting and hot rolling processes. Mechanical properties were evaluated by tensile tests conducted at a low strain rate 2 × 10-5 s-1 at 575, 600, and 625 °C. Microstructure of the steels was investigated via optical microscopy (OM) and electron transmission microscopy (TEM). The results show that when the content of W is fixed, the steel with 3.1 wt.% Co and the steel with 3.8 wt.% Co are found to obtain the best deformation resistance values at 575, 600, and at 625 °C; when the Co content is fixed, the steel with 1.5 wt.% W shows better performance. The highest ultimate tensile strength (UTS) and yield stress (YS) were achieved for the steel when its W content is at 1.5 wt.% and Co content is at 3.1 wt.% or 3.8 wt.%. Deformation resistance is related to the initial dislocation density in the steels, which increases with increasing Co content and decreases with increasing W content. It is verified that the deformation mechanism of the tested steels during high-temperature tensile tests at a low strain rate is that of the recovery-controlled dislocation creep. Furthermore, the thermodynamic calculation result is in agreement with the experimental result, demonstrating that 0.85Mo-1.5W-3.8Co steel has the best deformation resistance at 625 °C. Therefore, 0.85Mo-1.5W-3.1Co steel is recommended as a potential candidate material for 600 °C class steam turbines, and 0.85Mo-1.5W-3.8Co steel is also a potential material for 625 °C class Ultra supercritical (USC) steam turbines.

  11. Seasonal influence on heat-resistant proteolytic capacity of Pseudomonas lundensis and Pseudomonas fragi, predominant milk spoilers isolated from Belgian raw milk samples.

    Science.gov (United States)

    Marchand, Sophie; Heylen, Kim; Messens, Winy; Coudijzer, Katleen; De Vos, Paul; Dewettinck, Koen; Herman, Lieve; De Block, Jan; Heyndrickx, Marc

    2009-02-01

    Psychrotolerant bacteria and their heat-resistant proteases play a major role in the spoilage of UHT-processed dairy products. Summer and winter raw milk samples were screened for the presence of such bacteria. One hundred and three proteolytic psychrotolerant bacteria were isolated, characterized by API tests, rep-PCR fingerprint analysis and evaluated for heat-resistant protease production. Twenty-nine strains (representing 79% of the complete collection) were further identified by 16S rRNA gene sequencing, rpoB gene sequencing and DNA-DNA hybridizations. A seasonal inter- and intra-species influence on milk spoilage capacity (e.g. growth rate and/or protease production) was demonstrated. Moreover, this polyphasic approach led to the identification of Pseudomonas fragi and Pseudomonas lundensis (representing 53% of all isolates) as predominant producers of heat-resistant proteases in raw milk. The role of Pseudomonas fluorescens, historically reported as important milk spoiler, could not unequivocally be established. The use of more reliable identification techniques and further revision of the taxonomy of P. fluorescens will probably result in a different perspective on its role in the milk spoilage issue. PMID:19196277

  12. Properties of alloys on the titanium base for powerful steam turbine blades

    International Nuclear Information System (INIS)

    The results of investigation of VT20, VT22, AT6 titanium alloys properties under the conditions of blade operation of powerful steam turbines are considered. It is shown that VT20, VT22, AT6 alloys under investigation comply with the requirements of existing technical task according to short-term mechanical properties, fatigue strength, heat-resistant characteristics at operation temperature (100 deg C), VT20 and VT22 alloys also comply with the requirements for prospective turbines, AT6 alloy properties approach to these requirements. VT20 alloy meet the established requirements on perspectivity in the most complete way according to the most favourable combination of operation properties and to the level of separate characteristics

  13. Effect of yttrium on the cyclic oxidation behaviour of HP40 heat-resistant steel at 1373 K

    International Nuclear Information System (INIS)

    Research highlights: ? Yttrium has a benefit effect on the cyclic oxidation resistance of HP40 alloy. ? Y facilitates the formation of internal oxide (silica) during cyclic oxidation. ? A continuous spinel layer is observed on Y doped alloy during cyclic oxidation. ? The internal oxide (silica) improves the adherence of the scale. - Abstract: The effect of rare earth elements on cyclic oxidation behaviour of HP40 at 1373 K has been investigated. The results demonstrate that 0.06 wt.% addition of Y effectively improves the cyclic oxidation resistance of such Si-containing alloy. By observing the cross-section of the scale, it is found that Y facilitates the formation of Si-rich internal oxide, which improves the spalling resistance of the scale. As a result, compared with the sample without Y addition, on which the spinel layer is discontinuous, a continuous duplex scale of chromia overlaid by manganese-rich spinel is kept at the outmost of the Y-modified alloy.

  14. Forecasting of long-lived strength of structural steels and alloys

    International Nuclear Information System (INIS)

    The ways of forecasting of a long-term rupture strength for heat resistant steels and alloys are described. These methods are based on new temperature-time (temperature-force) dependences and the parametric law reducing the family of isotherms of durability to a unified parametric straight line. The results of the forecasting performed on the basis of the relations offered are confirmed by experimental data for chromium-molybdenum-vanadium and chromium-nickel steels as well as for an Inconel alloy

  15. Rolling of nickel base hardly deformable alloys in four-roller mills

    International Nuclear Information System (INIS)

    Results are presented of the optimization procedure relating to a new rod rolling technology in the case of hard-to-deform nickel alloys of the type EhP220VD and some others on four-high mills. The rods 22, 16 and 12 mm in diameter being rolled on the mills MK-165 and MK-200 show an adequate surface quality, high mechanical and heat-resistance properties. The main principles of the rolling technology as applied to the treatment of hard-to-deform nickel alloys developed

  16. Comparative assessment of filler wires for argon-arc welding of refractory alloys

    International Nuclear Information System (INIS)

    It is recommended to use wires of similar composition as filler material during argon-arc welding of heat resisting alloys, and Sv-08Kh20N57M8V8T3R wire - for welding of dispersion hardening alloys. Sv-06Kh15N60M15, Sv-KhN64KBMYuVF or Kh11N60M23 wires should be used as filler materials to decrease tendency of welded joints to cracking during welding and heat treatment

  17. Effect of surface protection measures on very high strength gas turbine materials. Pt. 2. Effect of structure. [Base materials: Alloy-IN-738 LC, Udimet 520, Alloy-IN-792, Alloy-IN-100, Alloy CMSX-2, Steel X53 CrMnNiN 21 9; coating material: Cr, PtAl, CrAl, NiCoCrAlY, CoNiCrAlY, NiCr

    Energy Technology Data Exchange (ETDEWEB)

    Sachova, E.; Hougardy, H.

    1987-01-01

    Corrosion protection coatings can have an effect on the creep behaviour of heat-resistant alloys by two mechanisms: 1. If the failure of uncoated samples is mainly determined by progressive corrosion on the surface, the time until fracture can be extended by applying a protective coating. 2. Due to heat treatment which is connected with applying the protective coating and by diffusion processes on the boundary of the protective coating during creep stress, the structure of the basic material may be changed and therefore the creep behaviour may be affected. The research project is intended to check to what extent the creep behaviour of heat-resistant alloys is changed by applying protective coatings, according to points 1 and 2 above. The metallographic test should clear up which of the above mechanisms was effective. Only broken samples are available for the total observation of structure. (orig./IHOE).

  18. Carburization of high chromium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ramanarayanan, T.A.; Petkovic, R.A.; Mumford, J.D.; Ozekcin, A. [Exxon Research and Engineering Co., Annandale, NJ (United States). Corporate Research Labs.

    1998-04-01

    Iron-nickel-chromium based heat resistant alloys are designed to operate at high temperatures in corrosive gaseous environments. Under mixed oxidizing-carburizing conditions, the microstructure of such materials changes progressively during service and the physical and mechanical properties are altered. One instance where such microstructural changes are encountered is in furnace tubes for pyrolysis applications. In the present study, kinetic experiments in the laboratory are combined with microstructural observations on alloys which have undergone long service times to develop an understanding of the fundamental processes that induce property changes in the material. Based on this study, four distinct stages are identified. These include: initial oxidation, oxidation in a carburizing environment, direct carburization and internal oxidation. Each of these stages is described. Questions are posed with respect to the sudden alteration in process stream chemistry or temperature. For instance, how does a drop in the oxygen partial pressure to levels where a chromium oxide film is unstable affect a preformed film? What beneficial effects are provided by inhibitors such as H{sub 2}S especially under conditions where an oxide film cannot form? (orig.) 23 refs.

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

    International Nuclear Information System (INIS)

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

  20. Results from investigations with an instrumented impact machine on a molybdenum base alloy, nickel base alloys, and Incoloy 800

    International Nuclear Information System (INIS)

    Experiments were performed on the molybdenum base alloy TZM, the nickel base alloys Nimocast 713 LC, Inconel 625, Nimonic 86, Hastelloy S, and the iron base alloy Incoloy 800 with an instrumented impact machine. The results are discussed in terms of absorbed impact energies and dynamic fracture toughness. In all cases the agreement between the energy determined by the dial reading and the energy determined by the integration of the load vs. load point displacement diagram was excellent. A procedure for the determination of the dynamic fracture toughness for load vs. load point displacement diagrams exhibiting high oscillations using an averaged curve is proposed. Using this procedure a pronounced influence of the experiments with tup and chisel (5.0 m/s and 0.1 m/s respectively) on the dynamic fracture toughness is not detectable. Using half the drop height, i.e. halving the total energy, lowers the dynamic fracture toughness values for these types of alloys. Low absorbed impact energies are often combined with high fracture toughness values. In these cases there is no or only a small reserve in deformation and/or stable crack growth. (Auth.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Prat, O., E-mail: oprat@udec.cl [Universidad de Concepción, Departamento de Ingeniería de Materiales, Edmundo Larenas 270, Concepción (Chile); García, J. [AB Sandvik Coromant R and D, Lerkrogsvägen 19, 12680 Stockholm (Sweden); Rojas, D.; Sanhueza, J.P.; Camurri, C. [Universidad de Concepción, Departamento de Ingeniería de Materiales, Edmundo Larenas 270, Concepción (Chile)

    2014-01-15

    Nucleation, growth and coarsening of three different precipitates (NbC, M{sub 23}C{sub 6} and V(C,N)) in a novel 9%Cr heat resistant steel designed by the authors were investigated. The microstructure evolution after tempering (780 °C/2 h) and after creep (650 °C/100 MPa) was characterized using transmission electron microscopy in the scanning mode (STEM). Thermodynamic and kinetic modeling was carried out using the softwares Thermo-Calc, DICTRA and TC-PRISMA. The Thermo-Calc software predicted formation of NbC, V(C,N) and M{sub 23}C{sub 6} carbides at the tempering temperature of 780 °C. STEM investigations revealed that M{sub 23}C{sub 6} precipitated on prior austenite grain boundaries and lath or block boundaries whereas NbC and V(C,N) were located within sub-grains. Simulations by TC-PRISMA showed that M{sub 23}C{sub 6}, NbC and V(C,N) particles nucleation begins as soon as the tempering treatment starts and it is completed in a very short time, reaching the equilibrium volume fraction after 40 s for M{sub 23}C{sub 6}, 100 s for NbC and 80 s for V(C,N). Best agreement between simulations and experimental investigations was found for low interfacial energy values of 0.1 J m{sup ?2}. Both STEM measurements as well as DICTRA simulations indicate very low coarsening rate for both kind of precipitates. Creep tests up to 4000–5000 h suggest that this special combination of NbC, V(C,N) and M{sub 23}C{sub 6} may provide increased pinning of dislocations reducing boundary migration therefore enhancing creep strength. - Highlights: • Nucleation, growth and coarsening of NbC and M{sub 23}C{sub 6} precipitates were investigated. • The microstructure was characterized using transmission electron microscopy (STEM). • Modeling was carried out using the softwares Thermo-Calc, DICTRA and TC-PRISMA. • M{sub 23}C{sub 6} and NbC nucleation begins as soon as the solution treatmentinitiates. • Best agreement modeling/experiments was found for low interfacial energy values of 0.1 J m{sup ?2}.

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

    International Nuclear Information System (INIS)

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

  3. Effect of Si and P on Microstructure and Mechanical Properties of Mg-7Al-1Zn-3.597Cu-xSi Alloys

    OpenAIRE

    Keqiang Qiu; Xiaocheng Wang; Junhua You

    2013-01-01

    In order to improve the heat resistant properties of magnesium alloys, the effects of P modification on phase constituent, microstructure and mechanical properties of Mg-7Al-1Zn-3.597Cu-xSi (x=1, 2, 3) alloys were investigated by means of x-ray diffractometer (XRD), scanning electron microscopy (SEM), and universal electronic testing machine. The results indicate that the Mg2Si phase presented in the form of Chinese script shape was observed in the microstructure of the alloy without P elemen...

  4. Constitutive equations for the creep behaviour of nickel-base alloys for HTR components in the temperature range 1023-1273 K

    International Nuclear Information System (INIS)

    The applicability and modification of constitutive equations for describing the creep and relaxation behaviour of the nickel-base alloys INCONEL 617, NIMONIC 86 and HASTELLOY S have been investigated. Creep tests at stresses in range 10-150 MPa and temperatures in the range 1023-1273 K were carried out for the three alloys and in addition for INCONEL 617 and HASTELLOY S relaxation and stress dip tests in the stress range 10-170 MPa and temperature range 1073-1223 K were performed. The fitting of various creep equations to the measured creep curves showed that the best description of the primary and secondary creep regions was given by the equation formulated by Li. Under the experimental conditions used, dislocation climb was the dominant deformation mechanism. Using the internal stress concept to account for the resistance to deformation, a Norton creep law exponent of 3 for INCONEL 617 was derived which is in agreement with the value calculated by Weertman for dislocation climb controlled screep in solid solutions. For HASTELLOY S a lower value was observed. The dependence of the internal stress in the temperature and stress range on creep strain, applied stress, deformation prior to testing, temperature and alloy composition was determined. Relaxation and stress dip tests showed two separate time dependent relationships for the reduction of stress or anelastic backstrain. A rapid decrease at the start of the test due to back glide of dislocations and a much slower decrease associated with recovery were observed. Calculation of the stress relaxation behaviour based on the Norton creep law alone led to a time dependence which was not reflected in the experimental results. However, taking into account the internal stress which decreases during the relaxation test due to recovery processes, it was possible to describe satisfactorily the experimentally determined relaxation curves. (orig.)

  5. Estimation of high-temperature strength of coast RuAl alloys and other monoaluminides by hot-hardness method

    International Nuclear Information System (INIS)

    Short- and long-term (holding under load up to 1 h) is measured at temperatures up to 1100 Deg C for coast monoaluminides RuAl, NiAl and TiAl serving as a basis for designing heat resistant composite material matrices intended for operation at temperatures in excess of those of modern nickel superalloys. It is shown that a more refractory RuAl surpasses the other monoaluminides in heat resistance within the whole temperature range studied. A more slow development of diffusion processes in RuAl alloys at 1100 Deg C predetermines a high stability of alloy hot hardness values. A single-phase alloy Ru51Al49 possesses the maximum hardness. A study of alloying effects shows that Hf, being most refractory having a great atomic radius and replacing Al in a RuAl B2-lattice, increases the hardness in heterogeneous alloys as exemplified by long-term testing. Titanium has no essential effect on hardness, and chromium promotes alloy softening somewhat

  6. Padrão eletroforético de proteínas resistentes ao calor em sementes de milho Electrophorectic pattern of the heat resistant proteins of corn seeds

    Directory of Open Access Journals (Sweden)

    Solange Carvalho Barrios Roveri José

    2005-02-01

    Full Text Available Na aquisição e manutenção da tolerância à dessecação de sementes, há vários mecanismos envolvidos, entre eles a indução das proteínas resistentes ao calor. O objetivo deste trabalho foi avaliar mudanças no padrão eletroforético das proteínas resistentes ao calor de sementes de milho submetidas a alta temperatura de secagem, associando-as à sua tolerância. Foram utilizadas sementes de linhagens, híbridos simples e híbridos recíprocos colhidas com teor de água de aproximadamente 35% e secadas a 45°C. Sementes das linhagens secadas à sombra foram utilizadas como controle e sua qualidade fisiológica foi avaliada por meio do teste de germinação. As proteínas resistentes ao calor foram extraídas de eixos embrionários das sementes em tampão Tris HCl 0,05 M. Não foi possível determinar uma banda específica da fração das proteínas resistentes ao calor que possa servir como marcador da tolerância à alta temperatura de secagem. Houve estabilidade nos padrões de bandas das proteínas provenientes de sementes submetidas à secagem artificial e natural, mesmo quando foram observadas variações nos valores de germinação. Os padrões eletroforéticos das proteínas resistentes ao calor foram semelhantes entre as sementes híbridas e os respectivos recíprocos.Several mechanisms are involved in the acquisition and maintenance of desiccation tolerance by the seeds. One of these mechanisms is related to the induction of heat resitant proteins. The objective of this work was to evaluate changes in the electophorectic patterns of the heat resistant proteins of corn seeds submitted to high drying temperature associating their expression with drying tolerance. Seeds of breeding lines, simple hybrids and respective reciprocals hybrids were utilized. The seeds were harvested with approximately 35% of water content and dried at 45°C. Seeds of lines dried under shadow were used as control and the physiological quality was evaluated by germination test. The heat resistant proteins were extracted from embryonic axis of seeds in Tris-HCl 0.05 M buffer. It was not possible to determine a specific band of heat resistant proteins which can be of use as a molecular marker of tolerance to high drying temperature. There was stability in the patterns of the bands of proteins of seeds submitted to artificial drying compared to the ones after shadow drying even for the lines of high variation in the germination values. The electrophorectic patterns of the heat resistant proteins were similar for both the hybrid seeds and respective reciprocals.

  7. Performance of aluminide coatings applied on alloy CF8C plus at 800 C

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Deepak [ORNL; Dryepondt, Sebastien N [ORNL; Shyam, Amit [ORNL; Haynes, James A [ORNL; Pint, Bruce A [ORNL; Armstrong, Beth L [ORNL; Lara-Curzio, Edgar [ORNL

    2011-01-01

    The cost effective, austenitic stainless steel CF8C plus is an attractive alloy for massive cast structures such as steam turbine casings. The microstructure stability and creep strength of this alloy are better than commercial high-performance heat-resistant steels such as NF709 and Super 304H, and are comparable to the Ni-based superalloy Inconel 617. The oxidation resistance of the alloy in atmosphere rich in water vapor is however insufficient at T>800 C, and the use of diffusion aluminide coatings is considered for potential high temperature applications. The thermal stability and protectiveness of coatings applied on the CF8C plus substrate by pack cementation and slurry process were investigated in air + 10% H2O environment at 800 C. Further, the coating effect on the fatigue life of the alloy was assessed via low-cycle-fatigue experiments.

  8. Ductility and resistance to deformation of EhP975 alloy during hot plastic working

    International Nuclear Information System (INIS)

    Results of investigations into ductility and resistance to deformation of the EhP975 most heat-resistant difficult-to-form alloy of commercial melting in 1000-1200 deg C temperature range and at deformation rates epsilon = 0.1 - 25 s-1 are presented. It is shown that ductility of EhP975 alloy grows rather slowly with increase of temperature approximately up to 1075 deg C, then sharp growth of ductility up to the maximum at 1120-1125 deg C is observed; ductility decreases above this temperature zone. It was also established that ductility of EhP975 alloy grows with increase of preliminary deformation degree. It is marked that high temperature annealing increases ductility of EhP975 alloy in comparison with (cast state), especially noticeably at high deformation rates

  9. Development of welding wire Sv-08Kh14N7KVM-VI for heat resisting stainless steels

    International Nuclear Information System (INIS)

    The Sv-08Kh14N7KVM-VI wire has been worked out to ensure productio of welded joints of stainless steel with ?sub(U.S.) >= 1200 MPa and to avoid embrittlement during prolonged (up to 500 h) heating in the 450-500 deg C temperature range. It is shown, that embrittlement of welded joints of martensite type stainless steels during prolonged heatings in the 450-500 deg C temperature range can be prevented in the case of complex alloying of the joint with molybdenum and tungsten (1%Mo+0.5%W) with titanium and aluminium additions

  10. High ion erosion rates produced on various stainless steels and nickel base alloys by 12 keV He+ ion bombardment

    International Nuclear Information System (INIS)

    Surface changes and ion erosion of stainless steels (316L) and nickel base alloys (Nimonic PE 16, Inconel 600, Hastelloy B) under 6-12 keV He+ ions bombardment at room temperature were systematically investigated using a profilometer, optical and electron microscopes. Results show that for the bombardment conditions mentioned sputtering yield, penetration depth and ion erosion for all materials studied are quite different from the available data. Blistering is found to be highly dependent on the surface preparation, annealing procedure, ion fluence and total ion dose. After 12 keV He+ ion bombardment etching effects were observed accompanied by blistering

  11. Cobalt-base alloys used in bone surgery.

    Science.gov (United States)

    Marti, A

    2000-12-01

    Cobalt-base alloys may be generally described as non magnetic, wear, corrosion and heat-resistant (high strength even at elevated temperature). Many properties of the alloy originate from the crystallographic nature of cobalt, the solid-solution-strengthening effect of chromium and molybdenum, the formation of extremely hard carbides and the corrosion resistance imparted by chromium. Cobalt-base alloys are difficult to fabricate which is why their use has been limited, but continuous work led to the development of specialized casting methods. Due to its excellent resistance to degradation in the oral environment, the first medical use of cobalt-base alloys was in the cast of dental implants. Various in vitro and in vivo tests have shown that the alloys are biocompatible and suitable for use as surgical implants. Today, the use of Co alloys for surgical applications is mainly related to orthopaedic prostheses for the knee, shoulder and hip as well as to fracture fixation devices. Joint endoprostheses are typical long-term implants and the applied implant material must therefore meet extremely high requirements with regard to biocompatibility with the surrounding body tissue material and corrosion resistance to body fluids. PMID:11270075

  12. Study of superficial films and of electrochemical behaviour of some nickel base alloys and titanium base alloys in solution representation of granitic, argillaceous and salted ground waters

    International Nuclear Information System (INIS)

    The corrosion behaviour of the stainless steels 304, 316 Ti, 25Cr-20Ni-Mo-Ti, nickel base alloys Hastelloy C4, Inconel 625, Incoloy 800, Ti and Ti-0.2% Pd alloy has been studied in the aerated or deaerated solutions at 200C and 900C whose compositions are representative of interstitial ground waters: granitic or clay waters or salt brine. The electrochemical techniques used are voltametry, polarization resistance and complexe impedance measurements. Electrochemical data show the respective influence of the parameters such as temperature, solution composition and dissolved oxygen, addition of soluble species chloride, fluoride, sulfide and carbonates, on which depend the corrosion current density, the passivation and the pitting potential. The inhibition efficiency of carbonate and bicarbonate activities against pitting corrosion is determined. In clay water at 900C, Ti and Ti-Pd show very high passivation aptitude and a broad passive potential range. Alloying Pd increases cathodic overpotential and also transpassive potential. It makes the alloy less sensitive to the temperature effect. Optical Glow Discharge Spectra show three parts in the composition depth profiles of surface films on alloys. XPS and SIMS spectrometry analyses are also carried out. Electron microscopy observation shows that passive films formed on Ti and Ti-Pd alloy have amorphous structure. Analysis of the alloy constituents dissolved in solutions, by radioactivation in neutrons, gives the order of magnitude of the Ni base alloy corrosion rates in various media. It also points out the preferential dissolution of alloying iron and in certain cases of chromium

  13. Application of high nickel alloys in the field of experience within corrosion resistance protection in flue gas desulphurization plants absorbers

    International Nuclear Information System (INIS)

    Absorbers are the main components of flue gas desulphurization plants for 360 MW power-generating units in Belchatow Power Plant. The whole plant operating cycle and its service life depend on the type of materials applied for corrosion resistance lining of various absorber zones. RAFAKO S.A. activities within this field are focused on the extension of FGD plant service life via implementation of technology of lining the cylindrical part of absorber with 0,5 - 1,6 mm thickness sheets made of Hastelloy type alloys of C-22 and C-2000 grade. The experiment carried out on Hastelloy C-22 and C-2000 alloy grades enabled the assessment of corrosion resistance properties of base material, lining plates, weld joints and HAZ. The paper contains the results of weld joints and HAZ structure assessment, weld joints corrosion resistance characteristics, results of corrosion products examinations as well as requirements and recommendations concerning the execution of weld joints, lining steel surface preparation for welding, etc. (authors)

  14. High-speed growth of YBa2Cu3O7?? superconducting films on multilayer-coated Hastelloy C276 tape by laser-assisted MOCVD

    International Nuclear Information System (INIS)

    The high-speed epitaxial growth of YBa2Cu3O7?? (YBCO) superconducting films on multilayer (CeO2/LaMnO3/MgO/Gd2Zr2O7)-coated Hastelloy C276 tape was demonstrated using laser-assisted metal–organic chemical vapour deposition (laser-assisted MOCVD). The preferred orientation of the YBCO films changed from a-axis to c-axis as the deposition temperature was increased from 769 to 913 K. The c-axis-oriented YBCO film exhibited a high critical temperature of 90 K and a high critical current density of 0.5 MA cm?2 even at a high deposition rate of 55 ?m h?1. (paper)

  15. Electrochemical corrosion studies on metallic packaging materials for high-level waste. Behavior of Hastelloy C 4 in quinary brine and 1 M NaCl solutions

    International Nuclear Information System (INIS)

    The temperature dependent current density - potential behavior of Hastelloy C 4 in Q-brine is determined for T=250C and T=900C. The material gets passivated instantaneously. The stability of the protecting passivated layer is greatly reduced at T >= 550C to 600C. Some of the specimens differ greatly from each other in their behavior which is attributed to inhomogeneities in the structure and composition of the materials. The results obtained from the electrochemical corrosion studies make evident a clear effectiveness of various impurities and radiolytic products potentially occurring in brines produced in an accident. These impurities and radiolytic products cause a destruction of this material through local corrosion depending on their concentration and time. (orig./PW)

  16. Investigation of weldability and property changes of high pressure heat-resistant cast stainless steel tubes used in pyrolysis furnaces after a five-year service

    International Nuclear Information System (INIS)

    Highlights: ? To investigate the weldability and property changes of high pressure heat-resistant cast stainless steel (HP) tubes. ? Welding was done by gas-tungsten arc welding (GTAW) process. ? Composition of precipitates was characterized by means of SEM and EDS analyses. ? The solution treatment was used to recover the properties of tubes. ? To investigate mechanical strength of specimens, tensile tests were carried out at room temperature. -- Abstract: High pressure heat-resistant cast stainless steel (HP steel) tubes produced by centrifugal casting are used in petrochemical industries for pyrolysis furnaces. They have appropriate ductility and weldability in as-cast conditions. These steels lose their ductility and weldability after being used in service and, hence, require repair. In the present study, the effect of metallurgical changes on weldability and ductility was investigated. The life span of the studied tubes was 5 years. Using electrodes with a chemical composition close to the base metal analysis, welding was done by gas-tungsten arc welding (GTAW) process. Solution treatment was used to recover the properties of tubes which can be useful, depending on metallurgical changes.

  17. Main directions in the work of the department of wear-and heat resistant cast irons for power engineering

    International Nuclear Information System (INIS)

    Some prospects for more wide utilization of castings of steels and cast irons in power engineering and for NPP equipment, in particular, are considered. It is shown that fabrication of important parts of alloyed cast iron with improved operational characteristics permits to reduce considerably the liquid metal consumption, but at the same time requires new casting methods. One of such methods is centrifugal casting which permits to produce big parts with the isotropic structure and homogeneous physical and chemical properties in different cross sections. This method is applied while manufacturing parts with the mass unbalanced relative to the axis and large-diameter tubes, including bimetallic ones (the 10GN2NFA+08Kh18N10T steels). The importance of development of modifying additions and methods of their injection into the melt while manufacturing high-quality cast irons are noted

  18. Estimation of the effects of alloying elements on molten salt corrosion

    International Nuclear Information System (INIS)

    In case of pure metals, pure metal of Mo showed higher corrosion resistance than other metals in molten salt of LiCl, and in mixed molten salt of LiCl-Li2O, pure metals of Ni, Fe, Mo showed higher corrosion resistance. In case of alloys, Incoloy 800H and Hastelloy C-276 showed higher corrosion resistance than other alloys, and in mixed molten salt of LiCl-Li2O, Fe-base alloy showed higher corrosion resistance than Ni-base alloy. The corrosion rate increased slightly with an increase of temperature up to 850 .deg. C in molten salt of LiCl. In mixed molten salt of LiCl-Li2O, the corrosion rate increased slowly with an increase of temperature up to 750 .deg. C, but above 750 .deg. C rapid increase in corrosion rate was observed. Corrosion products of alloys in mixed molten salt of LiCl-Li2O consisted of two phase structures - Li(Cr,Fe)O2 and Ni

  19. Effect of glass-ceramic-processing cycle on the metallurgical properties of candidate alloys for actuator housings

    Energy Technology Data Exchange (ETDEWEB)

    Weirick, L.J.

    1982-01-01

    This report summarizes the results from an investigation on the effect of a glass ceramic processing cycle on the metallurgical properties of metal candidates for actuator housings. The cycle consists of a 980/sup 0/C sealing step, a 650/sup 0/C crystallization step and a 475/sup 0/C annealing step. These temperatue excursions are within the same temperature regime as annealing and heat treating processes normally employed for metals. Therefore, the effect of the processing cycle on metallurgical properties of microstructure, strength, hardness and ductility were examined. It was found that metal candidates which are single phase or solid solution alloys (such as 21-6-9, Hastelloy C-276 and Inconel 625) were not affected whereas multiphase or precipitation hardened alloys (such as Inconel 718 and Titanium ..beta..-C) were changed by the processing cycle for the glass ceramic.

  20. Design of ductile polycrystalline Ni/sub 3/Al alloys

    International Nuclear Information System (INIS)

    This paper provides a comprehensive review of current efforts on design of ductile polycrystalline Ni/sub 3/Al alloys. Microalloying has proven to be very effective in alleviating the grain-boundary embrittlement problem. The ductility and fabricability of Ni/sub 3/Al (24 at. % Al) are dramatically improved by adding a few hundred parts per million of boron. The beneficial effect of boron is related to its unusual segregation behavior as predicted from the theory of grain-boundary cohesion developed by Rice, based on thermodynamic analyses. Alloy stoichiometry strongly influences grain-boundary chemistry, which, in turn, affects the boundary cohesion and overall ductility of Ni/sub 3/Al. The solid-solution hardening of Ni/sub 3/Al depends on the substitutional behavior of alloying elements, atomic size misfit, and the degree of nonstoichiometry of the alloy. Hafnium additions are very effective in improving high-temperature properties of ternary Ni/sub 3/Al (Al + Hf = 24 at. %) doped with boron. Alloying with ? 2% Hf substantially increases the yield stress and raises the peak-strength temperature. In addition, hafnium substantially improves creep properties and oxidation resistance. The Ni/sub 3/Al aluminides truly represent a new series of heat resistant materials which do not depend on chromium for oxidation resistance

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

    Science.gov (United States)

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

    2015-02-01

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural characteristics enable the 3D porous skeleton to own several favorable properties, including superior thermal stability, good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection function, etc. which give rise to acceptable battery performances. Considering the simply and cost-effective preparation process, the porous membrane is deemed to be an interesting direction for the future lithium ion battery separator.

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

    Science.gov (United States)

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

    2015-01-01

    Separators with high reliability and security are in urgent demand for the advancement of high performance lithium ion batteries. Here, we present a new and practical porous membrane with three-dimension (3D) heat-resistant skeleton and high curvature pore structure as a promising separator candidate to facilitate advances in battery safety and performances beyond those obtained from the conventional separators. The unique material properties combining with the well-developed structural characteristics enable the 3D porous skeleton to own several favorable properties, including superior thermal stability, good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection function, etc. which give rise to acceptable battery performances. Considering the simply and cost-effective preparation process, the porous membrane is deemed to be an interesting direction for the future lithium ion battery separator. PMID:25653104

  3. Effect of sporulation medium on wet-heat resistance and structure of Alicyclobacillus acidoterrestris DSM 3922-type strain spores and modeling of the inactivation kinetics in apple juice.

    Science.gov (United States)

    Molva, Celenk; Baysal, Ayse Handan

    2014-10-17

    Alicyclobacillus acidoterrestris is a spoilage bacterium in fruit juices leading to high economic losses. The present study evaluated the effect of sporulation medium on the thermal inactivation kinetics of A. acidoterrestris DSM 3922 spores in apple juice (pH3.82±0.01; 11.3±0.1 °Brix). Bacillus acidocaldarius agar (BAA), Bacillus acidoterrestris agar (BATA), malt extract agar (MEA), potato dextrose agar (PDA) and B. acidoterrestris broth (BATB) were used for sporulation. Inactivation kinetic parameters at 85, 87.5 and 90°C were obtained using the log-linear model. The decimal reduction times at 85°C (D85°C) were 41.7, 57.6, 76.8, 76.8 and 67.2min; D87.5°C-values were 22.4, 26.7, 32.9, 31.5, and 32.9min; and D90°C-values were 11.6, 9.9, 14.7, 11.9 and 14.1min for spores produced on PDA, MEA, BATA, BAA and BATB, respectively. The estimated z-values were 9.05, 6.60, 6.96, 6.15, and 7.46, respectively. The present study suggests that the sporulation medium affects the wet-heat resistance of A. acidoterrestris DSM 3922 spores. Also, the dipicolinic acid content (DPA) was found highest in heat resistant spores formed on mineral containing media. After wet-heat treatment, loss of internal volume due to the release of DPA from spore core was observed by scanning electron microscopy. Since, there is no standardized media for the sporulation of A. acidoterrestris, the results obtained from this study might be useful to determine and compare the thermal resistance characteristics of A. acidoterrestris spores in fruit juices. PMID:25129530

  4. Effect of rare earth element yttrium addition on microstructures and properties of a 21Cr-11Ni austenitic heat-resistant stainless steel

    International Nuclear Information System (INIS)

    Research highlights: ? Applications of Y in 21Cr-11Ni austenitic heat-resistant stainless steel. ? Sensible characteristics of microstructure and properties have been observed. ? Y has been found be effective in improving hot ductility of 21Cr-11Ni steel. ? Inhibitory effect of Y on S segregation to the grain boundary has been observed. -- Abstract: In this comparative study, the microstructure and the mechanical properties of a 21Cr-11Ni austenitic heat-resistant stainless steel with and without addition of rare earth (RE) element yttrium have been investigated. The results show that a number of fine spherical yttrium-rich oxide particles are not uniformly distributed in the matrix of steel with yttrium; instead, they are aligned along the rolling direction. The grains surrounding the alignment are nearly one order of magnitude smaller than those farther away from the alignment. The approximate calculation results indirectly show that the grain refinement may be mainly attributed to the stimulation for nucleation of recrystallization rather than to pinning by particles. Furthermore, the alignment has resulted in significant loss in transverse impact toughness and tensile elongation at room temperature. There is a trough in the hot ductility-temperature curve, which is located between 973 and 1173 K. The ductility trough of steel with yttrium becomes shallow within a certain temperature range, especially around 1073 K, indicating that improvement on hot ductility is achieved by yttrium addition. The results may be attributed to the increase of grain boundary cohesion indicated by the effective improvement on intergranular failure tendency, and the inhibitory effect of yttrium on sulfur segregation to grain boundaries is believed to be an important cause.

  5. Nonswelling alloy

    International Nuclear Information System (INIS)

    An aluminum alloy containing one weight percent copper has been found to be resistant to void formation and thus is useful in all nuclear applications which currently use aluminum or other aluminum alloys in reactor positions which are subjected to high neutron doses

  6. Cast Intermetallic Alloys and Composites Based on Them by Combined Centrifugal Casting—SHS Process

    Directory of Open Access Journals (Sweden)

    Vladimir Sanin

    2013-08-01

    Full Text Available This work aims to establish a scientific and engineering background in the production of cast multicomponent alloys and metalmartix composite (MMCs via Self-Propagating High Temperature Synthesis (SHS, combustion synthesis which is a novel process technique regarding fast and low-cost production ability. We carried out the search for reactive systems and process parameters that would ensure preparation of cast multicomponent materials in a single process. The principles and methods of the SHS thermite-type reaction processes have been investigated under high-gravity values applying loads up to 1000 g with special centrifuge set-up. In this way we expected to improve the yield of target product, remove gaseous byproducts, diminish the grain size in the product, and make product composition more uniform. The obtained results can be expected to make a theoretical background for industrial-scale manufacturing of heat-resistant intermetallic alloys, master alloys, catalysts, MMCs etc.

  7. Bimetallic layered castings alloy steel – grey cast iron

    Directory of Open Access Journals (Sweden)

    T. Wróbel

    2011-04-01

    Full Text Available Purpose: In paper is presented technology of bimetallic layered castings based on founding method of layer coating directly in cast process so-called method of mould cavity preparation.Design/methodology/approach: Prepared bimetallic layered castings consist two fundamental parts i.e. bearing part and working part (layer. The bearing part of bimetallic layered casting is typical foundry material i.e. pearlitic grey cast iron, whereas working part (layer is depending on accepted variant plates of alloy steels sort X6Cr13, X12Cr13, X10CrNi18-8 and X2CrNiMoN22-5-3. The ratio of thickness between bearing and working part is 8:1. The verification of the bimetallic layered castings was evaluated on the basis of ultrasonic NDT (non-destructive testing, structure and macro- and microhardness researches. Moreover was made computer simulation of solidification of bimetallic layered casting in NovaFlow&Solid software.Findings: The results of studies and their analysis show efficiency of new, innovative technology of corrosion and heat resisting layered castings.Research limitations: In further research, authors of this paper are going to application of different material on bearing part of bimetallic layered casting.Practical implications: Prepared bimetallic layered castings according to work out technology can work in conditions, which require from working surface layer of element a high heat resistance and/or corrosion resistance in medium for example of industrial water.Originality/value: The value of this paper resides in new effective method of manufacture of heat resisting castings, mainly for lining of quenching car to coke production

  8. Life Evaluation of High Cr Alloy Weldment according to the Oxidation Properties

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Si Yeon; Jeong, Baek Soon; Heo, Jae Sil [KEPCO Research Institute, Daejeon (Korea, Republic of)

    2011-10-15

    There has been strong environmental and economic pressure to increase the thermal efficiency of fossil fuel power stations and this has led to a steady increase in steam temperature and pressure resulting in worldwide plans for ultra super-critical power plants. Therefore, in order to improve the thermal efficiency of power plants, there has been a strong drive to develop heat resistant steels with excellent creep, high temperature fatigue and thermal fatigue resistant properties as well as superior oxidation and corrosion resistant properties. Cr-Mo steels are extensively used for high temperature components in power plants. In this study, the test materials were P122 alloy which have been developed for ultra super-critical power plant. In power plants, lot of mechanical components is welded and generally, HAZ is reported to be the weakest part of the welded components and serves as frequent crack initiating sites. Also, HAZ was found to have the lowest toughness in welded joints. In characterizing the mechanical property of heat resistant alloys, the fundamental knowledge of oxidation at high temperature is of great importance. Oxidation has been considered to be the major detrimental phenomenon that interacts with low cycle fatigue in high temperature range. It is reported also to influence the crack initiation process in alloys and the large fraction of fatigue life is spent in the crack initiation process. Therefore, it is very important to approach such problems from the view point of high temperature material properties

  9. Modelling the directional solidification of casting from high-temperature alloy under action of electric current

    International Nuclear Information System (INIS)

    A 3d-mathematical model of directional solidification of castings under the action of electric current is developed. The optimal relationship of current intensity to heat flux density in a given area of the casting-mold interface is determined. Casting parameters calculated on the basis of the mathematical model are used in the process of casting a batch of gas turbine engine blades of a heat resistant alloy ChS88UVI. The castings obtained meet the requirements to blades in density and mechanical properties

  10. Metal dusting behaviour of furnace tube alloys

    Directory of Open Access Journals (Sweden)

    Abdulaziz Al-Meshari

    2009-10-01

    Full Text Available Metal dusting has long been a chronic problem for several industrial sectors. In order to obtain a better understanding of the aspects of this failure mode, three heat-resistant alloys, KHR35C HiSi©, KHR45A LC©, and UCX© were exposed to a gas mixture of 80 vol% CO+20 vol% H2 flowing at 100cm3 min-1 at 650, 750, and 850ºC for 100h. The alloys were then characterised by visual examination, XRD, and SEM/EDX. In conclusion, KHR35C HiSi© suffered localised metal dusting at 650 and 750ºC and the attack became less aggressive with the temperature increase. The least attack on KHR35C HiSi© was however observed after exposure at 850ºC. The corrosion mode at each temperature was also elucidated. Pitting also occurred on KHR45A LC© after exposure at 650ºC but to a lesser degree compared to KHR35C HiSi©. Moreover, a few pits were observed on KHR45A LC© exposed at 750ºC with the least took place at 850ºC. UCX©, which contained the highest concentrations of chromium and nickel, exhibited the best resistance to metal dusting at the test temperatures.

  11. Isolamento e seleção de fungos filamentosos termorresistentes em etapas do processo produtivo de néctar de maçã / Isolation and selection of heat resistant molds in the production process of apple nectar

    Scientific Electronic Library Online (English)

    Beatriz de Cássia Martins, Salomão; Pilar Rodriguez, Massaguer; Gláucia Maria Falcão, Aragão.

    2008-03-01

    Full Text Available SciELO Brazil | Language: Portuguese Abstract in portuguese Os fungos filamentosos termorresistentes são capazes de sobreviver aos processos de pasteurização aplicados aos produtos de frutas. Este estudo visou isolar e identificar fungos termorresistentes durante o processamento de néctar de maçã (pH 3,4 e 11,6 °Brix), de forma a selecionar o bolor mais term [...] orresistente. O isolamento foi obtido após choque térmico de 70 °C/2 horas e incubação a 30 °C em PDA (3% de ágar) acrescido de rosa de bengala. A identificação foi baseada na morfologia e nas estruturas micro e macroscópicas observadas após incubação das cepas em três diferentes meios (G25N, CYA e MEA) e temperaturas. O fungo mais termorresistente foi selecionado pela aplicação de choques térmicos (de 80 °C/20 minutos até 97 °C/15 minutos). Foram detectadas 11 linhagens de bolores, sendo 5 termorresistentes. Dentre estas, três cepas, isoladas da matéria-prima e do concentrado de maçã, foram identificadas como Neosartorya fischeri; uma cepa isolada da matéria-prima foi identificada como Byssochlamys fulva, e uma cepa isolada do produto após a primeira pasteurização foi identificada como Eupenicillium sp. As cepas mais resistentes foram as de N. fischeri e B. fulva, que sobreviveram ao tratamento de 95 °C/20 minutos. Dentre as seis cepas restantes, uma foi identificada como Aspergillus sp., entretanto, nenhuma destas apresentou termorresistência. Abstract in english Heat resistant molds are able to survive the pasteurization process applied to apple products. This study aimed at detecting and identifying heat resistant molds during the processing of apple nectar (pH 3.4; 11.6 °Brix) in order to select the most heat resistant mold. The isolation was carried out [...] after heat shock at 70 °C, during 2 hours, and incubation at 30 °C, in PDA (3% agar), where rose bengal was added. The identification of macro and microscopic structures was carried out after incubation in three different media (G25N, CYA, MEA) and temperatures. Different heat shocks, from 80 °C/20 minutes to 97 °C/15 minutes, were applied to select the most heat resistant mold. Eleven strains were selected, of which five were heat-resistant: three strains were isolated from apple and concentrated apple juice and were identified as Neosartorya fischeri; one strain, isolated from apple, was identified as Byssochlamys fulva and one strain, isolated from the product after the first pasteurization, was identified as Eupenicillium sp. The most heat-resistant strains belong to N. fischeri and B. fulva, which were able to survive at 95 °C/20 minutes. Among the six remaining, one was identified as Aspergillus sp., however, none of them was heat resistant.

  12. Influence of impurities in phosphoric acid on the corrosion resistance of some commercially produced alloys

    Energy Technology Data Exchange (ETDEWEB)

    Nassif, N.

    1985-11-01

    The influence of Cl/sup -/, F/sup -/, S/sup 2 -/, SO/sub 4//sup 2 -/, SiO/sub 3//sup 2 -/, Fe/sup 3 +/, Al/sup 3 +/, Ca/sup 2 +/ and Mg/sup 2 +/ ions, in phosphoric acid, on the corrosion behaviour of stainless steels 304 and 316, alloys 825, 625, 230 and Hastelloys C and G was investigated. The alloys were tested in 75% H/sub 3/PO/sub 4/ in the absence and presence of various concentrations of each of the impurities at 85/sup 0/C under reflux and stirring conditions. Chloride ion was the most aggressive of the impurities because of its physicochemical properties. The best corrosion resistance in chloride contaminated H/sub 3/PO/sub 4/ was shown by the alloy containing the highest molybdenum and tungsten contents as an insoluble protective basic molybdenum and tungsten chloride film is formed. The presence of sulphide ion in H/sub 3/PO/sub 4/ considerably affected the corrosion rate as a result of the increased electrocatalytic activity of the passive film for oxygen reduction as a result of film contamination. Corrosion resistance was improved in such a sulphide environment by increasing the chromium content of the alloys. (orig.).

  13. Behaviour of metals and alloys in molten fluoride media

    International Nuclear Information System (INIS)

    Fluoride salts are contemplated for Generation IV nuclear systems which structural materials need to resist corrosion at high temperatures. Corrosion of metals in molten fluorides has been investigated in support of the Molten Salt Reactor's development and led to an optimized alloy, Hastelloy-N, but it lacked fundamentals data for the comprehension of materials' degradation mechanisms. The main objective of this work is then to help with the understanding of the corrosion behaviour of nickel and its alloys in fluoride salts. An experimental method was built up using electrochemical techniques and enabled to investigate the thermochemical conditions of the media and the influence of different parameters (media, temperature and quantity of impurities) on the behaviour of the materials. Most tests were performed in LiF-NaF mixtures between 800 and 1000 C. Pure metals can be classified as follows: Cr ? Fe ? Ni ? Mo ? W in increasing stability order and two specific behaviours were evidenced: Cr and Fe corrode in the melt, whereas Ni, Mo and W are stable, underlining the significance level of the redox couple controlling the reactions in the mixture. Moreover, corrosion current densities increase with temperature, fluoro-acidity and the quantity of dissolved oxide in the melt. Binary Ni-Cr alloys were also tested; selective attack of Cr is first observed before both elements are oxidized. Combining thermochemical calculations and experimental results enables to propose an approach to establish an optimized composition for a stable alloy. Immersion tests were finally achieved in addition to the electrochemical tests: interpretations of both methods were compared and completed. (author)

  14. Enhancement of carburization/oxidation resistance in fossil fuel environments through alloy compositional optimization

    Energy Technology Data Exchange (ETDEWEB)

    Baker, B.A.; Smith, G.D.; Tassen, C.S. [INCO Alloys International, Inc., Huntington, WV (United States)

    1996-08-01

    Carburization resistance of numerous heat resistant alloys has been evaluated in equilibrated atmospheres having a wide range of oxygen potentials. This paper attempts to characterize and explain alloy performance in these simulated fossil fuel environments on the basis of alloy content and scale characteristics and discusses means of further improvements in performance. A survey of current information regarding scale characteristics of wrought nickel-base alloys is also presented. Typical carburizing service environments contain at least some level of oxygen. Such applications include heat treating, ethylene pyrolysis, coal conversion, activated carbon production and steam hydrocarbon reforming. Carburization usually plays some role in the ultimate failure of an alloy; it often compromises creep and fatigue life and/or ductility. Conversely, creep, fatigue and thermal cycling can cause protective scales to crack and spall, thereby compromising carburization resistance. To maximize carburization resistance in future alloys, attention must be paid not only to corrosion performance in static environments but also to scale-alloy compatibility, growth stresses, creep and thermal gradient stresses, and inward and outward diffusion coefficients, and scale repairability.

  15. The effect of Ca addition on microstructures and mechanical properties of Mg-RE based alloys

    International Nuclear Information System (INIS)

    Highlights: ? Calcium can be used to refine ?-Mg grains in the Mg-RE based magnesium alloy. ? Calcium causes some thermally stable intermetallic compound phases. ? Those stable phases can effectively improve the mechanical property. ? Unknown four elementary phases are formed at the grain boundary. -- Abstract: AM-SC1 (Advanced Magnesium-Sand Casting Alloy 1) is a heat-resisting Mg-RE based alloy which has been widely applied in engine block. It would be an effective way to decrease the cost of the alloy by replacing Nd with Ca as addition. The effects of Ca addition on the microstructure and mechanical properties of the alloy were investigated by means of Brinell hardness measurement, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction and tensile tests at room and elevated temperatures. As the addition of Ca is 1.5%, the alloy shows the finest grain size of 16 ?m which also contributes to the highest hardness and strength of 62.1 HB and 148 MPa, respectively. After T6 treatment (solid solution treatment at 500 °C for 7 h and aging treatment at 200 °C for 20 h), the morphologies of the phases in the Ca-containing alloys change from net-like to fine short-block and particle-like shapes, and its strengths at RT, 175 °C and 200 °C are correspondingly improved to 186 MPa, 166 MPa and 140 MPa, respectively

  16. The effect of Ca addition on microstructures and mechanical properties of Mg-RE based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jin-shan, E-mail: jinshansx@tom.com [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Sun, Yan; Cheng, Wei-li; Que, Zhong-ping; Li, Yong-mei [College of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Liushan, Liangzi [School of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China)

    2013-03-25

    Highlights: ? Calcium can be used to refine ?-Mg grains in the Mg-RE based magnesium alloy. ? Calcium causes some thermally stable intermetallic compound phases. ? Those stable phases can effectively improve the mechanical property. ? Unknown four elementary phases are formed at the grain boundary. -- Abstract: AM-SC1 (Advanced Magnesium-Sand Casting Alloy 1) is a heat-resisting Mg-RE based alloy which has been widely applied in engine block. It would be an effective way to decrease the cost of the alloy by replacing Nd with Ca as addition. The effects of Ca addition on the microstructure and mechanical properties of the alloy were investigated by means of Brinell hardness measurement, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction and tensile tests at room and elevated temperatures. As the addition of Ca is 1.5%, the alloy shows the finest grain size of 16 ?m which also contributes to the highest hardness and strength of 62.1 HB and 148 MPa, respectively. After T6 treatment (solid solution treatment at 500 °C for 7 h and aging treatment at 200 °C for 20 h), the morphologies of the phases in the Ca-containing alloys change from net-like to fine short-block and particle-like shapes, and its strengths at RT, 175 °C and 200 °C are correspondingly improved to 186 MPa, 166 MPa and 140 MPa, respectively.

  17. Fuel behavior in severe accidents and Mo-alloy based cladding designs to improve accident tolerance

    International Nuclear Information System (INIS)

    The severe accidents at TMI-2 and Fukushima-Daiichi led to core meltdown and hydrogen explosions. The main source of energy causing core melting is the decay heat from ?-, ?+, and ? decays of short-lived isotopes following a power scram. The exothermic reaction of Zr-alloy cladding can further increase the cladding temperature leading to rapid cladding corrosion and hydrogen production. The most effective mitigation to minimize core damage in a severe accident is to extend the duration of heat removal capacity via battery-supported passive cooling for as long as practically possible. Replacing the Zr-alloy cladding with a higher heat resistant cladding with lower enthalpy release rate may also provide additional coping time for accident management. Such a heat resistant cladding may also overcome the current licensing concerns about Zr-alloy hydriding and post quench ductility issues in a design base loss of coolant accident (LOCA). Zr-alloy cladding, while has been optimized for normal operation in high pressure water and steam of light water reactors, will rapidly lose its corrosion resistance and tensile and creep strength in high pressure steam. Evaluation of alternate cladding materials and designs have been performed to search for a new fuel cladding design which will substantially improve the safety margins at elevated temperatures during a severe accident, while maintaining the excellent fuel performance attributes of the current Zr-alloy cladding. The screthe current Zr-alloy cladding. The screening criteria for the evaluation include neutronic properties, material availability, adaptability and operability in current LWRs, resistance to melting. The new designs also need to be fabricable, maintain sufficient strength and resist to attack by high pressure steam. Engineering metals, alloys and ceramics which can meet some or most of these requirements are limited. Following review of the properties of potential candidates, it is concluded that molybdenum alloys may potentially achieve the largest improvement in fuel safety margins in a severe accident. To adopt molybdenum alloys for LWR fuel cladding application, a novel design of duplex and triplex Mo-Zr or Mo-advanced steel cladding is proposed as the best candidate for further development. The technical basis for selecting the Mo-Zr cladding out of several other potential candidates, and the approaches to overcome the weakness of the molybdenum alloys are discussed. (orig.)

  18. Effects of working temperature and carbon diffusion on the microstructure of high pressure heat-resistant stainless steel tubes used in pyrolysis furnaces during service condition

    International Nuclear Information System (INIS)

    Highlights: ? Microstructure of HP tubes used in pyrolysis furnaces during service condition was studied. ? Two major phases, namely chromium and niobium carbides, existed in HP tubes in as-cast conditions. ? Temperature and carbon diffusion influence the composition and volume fraction of secondary precipitates. ? Chromium and niobium carbides were transformed to M23C6 and G-phase respectively during service. -- Abstract: In the present study, high pressure heat-resistant cast stainless steels (HP steels) modified with niobium and titanium were investigated in as-cast conditions and after being used in pyrolysis furnaces. Life span of the studied specimens obtained from pyrolysis furnace was 5 years. Microstructural changes were studied via scanning electron microscopy (SEM) equipped with energy dispersive spectrum (EDS), optical microscopy (OM), and X-ray diffraction (XRD). The effect of temperature and carbon diffusion on the microstructure, chromium-rich carbides, the NbC transformation to G-phase and other precipitates formed during service condition were discussed. The results showed that two major phases, namely chromium and niobium carbides, existed in the as-cast specimens. Temperature and carbon diffusion influenced the composition and volume fraction of secondary precipitates. Chromium and niobium carbides were transformed to M23C6 and G-phase respectively during service. Higher working temperatures do not always cause coarsening of precipitates. However, factors such as decarburization and carbon diffusion have important roles, too.

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

    International Nuclear Information System (INIS)

    The function of one or more heat shock proteins (HSPs) may be to confer protection to cells against thermal damage. The quantitative relationship between heat sensitivity and concentration of several HSPs in thermotolerant Chinese hamster HA-1 cells and in their stable heat resistant variants (3011 and 2242) were examined. The presence or concentration of low molecular weight HSPs (22-27 kd) showed no correlation with cell survival after heat shock. In contrast, the concentration of 70 kd HSP correlated well with the logarithm of cell survival. To summarize, the data indicate that if any of the HSPs is indeed responsible for providing protection against heat-induced cell death, then the 70 kd HSP is the most likely candidate. It is not the rate of synthesis that is of importance, but the absolute level of this HSP. Furthermore, it does not matter whether the protein is induced in response to an earlier heat shock or is present in constitutive form. In either case the level of 70 kd HSP appears to be a good predictor of heat response

  20. Effect of microstructural evolution on high-temperature strength of 9Cr–3W–3Co martensitic heat resistant steel under different aging conditions

    International Nuclear Information System (INIS)

    Evolution of microstructures and high-temperature strength at 650 °C of 9Cr–3W–3Co martensitic heat resistant steel after aging at 650 °C and 700 °C for different time durations have been experimentally investigated using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM) and post-aged tensile tests. The results show that after aging at 650 °C, the high-temperature strength and the microstructures of 9Cr–3W–3Co steel keep almost stable with increasing aging time from 300 h to 3000 h. In comparison, after aging at 700 °C, there are obvious changes in the high-temperature strength and the microstructures. The strengthening mechanisms of the 9Cr–3W–3Co steel were also discussed and the athermal yield stresses were calculated. The change of the high-temperature strength is mainly affected by the evolution of dislocations and laths. The precipitates mainly act as obstacles against motion of dislocations and lath boundaries

  1. Effects of carbon on creep-rupture strength and toughness of high Cr-Mo heat resisting steels containing V and Nb

    International Nuclear Information System (INIS)

    Effects of carbon on creep-rupture properties and room temperature toughness of high (9 ? 10)Cr-(1.8 ? 2)Mo ferritic heat resisting steels containing V and Nb were studied. The carbon content was varied from 0.02 to 0.23 % in order to improve toughness without decreasing the creep-rupture strength. Difference existing in creep-rupture strength and in Charpy absorbed energy between 10Cr-2Mo steels and 9Cr-1.8Mo steels were studied with respect to the ratio of delta ferrite to martensite, the precipitates, and the microstructure. The results indicated that the 9Cr-1.8Mo-0.1V-0.05Nb steels with 0.14 % C tempered at 800 deg C showed good toughness, and that 104 h rupture-strength of the steel was as high as that of SUS 316 austenitic stainless steel at 550 deg C and SUS 304 at 600 deg C. It was concluded that the optimum amount of delta ferrite from the point of view of creep-rupture strength and Charpy absorbed energy was 10 ? 20 %. (author)

  2. Effect of microstructural evolution on high-temperature strength of 9Cr–3W–3Co martensitic heat resistant steel under different aging conditions

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Peng, E-mail: maxeric@163.com [Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China); Institute for Special Steels, China Iron and Steel Research Institute, Beijing 100081 (China); Liu, Zhengdong; Bao, Hansheng [Institute for Special Steels, China Iron and Steel Research Institute, Beijing 100081 (China); Weng, Yuqing [Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China); Liu, Wei, E-mail: liuw@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials of Ministry of Education of China, School of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China)

    2013-12-20

    Evolution of microstructures and high-temperature strength at 650 °C of 9Cr–3W–3Co martensitic heat resistant steel after aging at 650 °C and 700 °C for different time durations have been experimentally investigated using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), field emission transmission electron microscopy (FETEM) and post-aged tensile tests. The results show that after aging at 650 °C, the high-temperature strength and the microstructures of 9Cr–3W–3Co steel keep almost stable with increasing aging time from 300 h to 3000 h. In comparison, after aging at 700 °C, there are obvious changes in the high-temperature strength and the microstructures. The strengthening mechanisms of the 9Cr–3W–3Co steel were also discussed and the athermal yield stresses were calculated. The change of the high-temperature strength is mainly affected by the evolution of dislocations and laths. The precipitates mainly act as obstacles against motion of dislocations and lath boundaries.

  3. Well wrapped eggs: effects of egg shell structure on heat resistance and hatchling mass in the invasive land snail Cornu aspersum.

    Science.gov (United States)

    Nicolai, Annegret; Vernon, Philippe; Lenz, Roman; Le Lannic, Joseph; Briand, Valérie; Charrier, Maryvonne

    2013-02-01

    In ectotherms, the temperature changes that accompany climate shifts, microhabitat changes, and species range extensions can have profound effects on the performance of organisms. The aim of this laboratory study on the terrestrial invasive gastropod Cornu aspersum was to investigate the effect of dietary calcium source on egg shell structure and heat resistance of eggs in two populations from different climatic regions of France (Western Atlantic and Mediterranean). To date no literature is known about heat stress in calcified ectothermic eggs while exposed to heat peaks using fluctuating thermal regimes and optimal humidity. In snails from the Mediterranean population fed exclusively with CaCO(3) from limestone we found the thinnest egg shells and the smallest hatchlings. Limestone represents the most accessible calcium source for snails, but is, however, responsible for thinner and more mineralized egg shells (higher ash content). Hence thicker egg shells result from a low mineralized mucopolysaccharide-glycoprotein matrix that could play a nutritional role for hatchlings. Exposed to heat peaks, eggs in both populations had lower incubation time variability at the detriment of hatching rate. This study highlights the need for functional studies in this invasive species to understand the effects on population dynamics of interacting biotic and abiotic environmental factors under climate and anthropic habitat changes. PMID:23213023

  4. Determination of the alloyed amount of cerium and microdistribution of cerium in steel, cast iron and aluminium by radioassay and autoradiography

    International Nuclear Information System (INIS)

    An experimental method for the determination of the amount of rare earth alloyed in steel, cast iron, aluminium and its alloy and a coating-autoradiography technique have been developed. Microautoradiographs show that the cerium is distributed in the grains, but cerium mainly segregates along the grain boundaries and dendrite boundaries of aluminium, Al-Mg alloys and heat-resisting Fe-Cr-Al alloys. Cerium contained in the pearlite is more than that in the ferrite of 16Mn and 25MnTiB steels. There is little cerium in the ferrite and pearlite which surround the spheroidal graphite, while in the pearlite and ledeburite which are located far from the spheroidal graphite there is much cerium. Cerium is distributed uniformly in flake graphite, while it is distributed in various ways in spheroidal graphite. (orig.)

  5. Effect of tungsten on the microstructure evolution and mechanical properties of yttrium modified HP40Nb alloy

    International Nuclear Information System (INIS)

    Highlights: ? W facilitates the formation of Cr23C6 during the solidification of HP40 alloy. ? W addition inhibits the precipitation of secondary carbide during aging. ? 'Necklace like' chromium carbide is first been observed during NbC transformation. ? By inhibiting the G phase transformation, it restrains the tensile strength declining of alloy. - Abstract: This paper investigates the effect of tungsten on the microstructure evolution and mechanical properties of yttrium modified HP40Nb heat-resistance steel. The results demonstrate that, under the casting condition, tungsten addition refines the austenite grain and accelerates the carbide transformation from Cr7C3 into Cr23C6. In addition, tungsten reduces the solid solubility of carbon in austenite grain, and thus inhibits the carbide precipitation during aging at 900 deg. C. Besides, tungsten suspends the phase transformation of NbC. As a result, the fracture resistance is improved on the tungsten-adopted alloy.

  6. Phase equilibria in Ni-TiC-MeC (Me: Zr, Hf, Nb, Ta) system alloys

    International Nuclear Information System (INIS)

    Phase equilibria in heat resisting Ni-TiC-MeC(MeZr, Hf, Nb, Ta) system alloys were investigated. Metalographic analysis was used to study cast and annealed alloys. Phase equilibria diagram of Ni-TiC-ZrC system posesses one ternary eutectic melting at the temperature of 1175+-15 deg C and containing 6+-0.7 mol.% TiC and 4+-0.7 mol % ZrC. Two carbide phases are formed in this system alloys which composition corresponds to the position of solid solution binodal decomposition curve in quasibinary TiC-ZrC system. The state diagram of Ni-TiC-HfC system is similar to the one of Ni-TiC-ZrC system. Cast alloys of this system show a tendency to crystallizationin metastable state when carbide phase doesn't decompose into two solid solutions. In Ni-TiC-TaC system alloys carbide phase doesn't decompose even during annealing (1000 deg C, 10 hours). State diagrams of these systems possess one monovariant eutectic. When obtaining carbide phases using metallic bath the most reliable results are received when alloys with eutectic compositions are used

  7. Some peculiarities of arc welding of heat pipes of the Kh28N48V5 cast alloy

    International Nuclear Information System (INIS)

    Use of argon-electric arc welding of radiation pipes made it possible to considerably improve the strength of the welding joint and provide uninterrupted operation of thermal furnaces at the Pervouralsk Novotrubny Works. The method was applied in welding U-pipes consisting of a heat-resistant alloy, Kh28N48B5, suitable for making new and for repairing spent pipes of this type. For the first layer - GSl and for the second layer - OZL-31, electrodes were used with reversed polarity d.c. under conditions involving preheating of the welding spot to 600-700 deg C

  8. Fuel behavior in severe accidents and Mo-alloy based cladding designs to improve accident tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Bo [Electric Power Research Institute, Palo Alto, CA (United States). Nucler Power Sector

    2013-03-15

    The severe accidents at TMI-2 and Fukushima-Daiichi led to core meltdown and hydrogen explosions. The main source of energy causing core melting is the decay heat from {beta}-, {beta}+, and {gamma} decays of short-lived isotopes following a power scram. The exothermic reaction of Zr-alloy cladding can further increase the cladding temperature leading to rapid cladding corrosion and hydrogen production. The most effective mitigation to minimize core damage in a severe accident is to extend the duration of heat removal capacity via battery-supported passive cooling for as long as practically possible. Replacing the Zr-alloy cladding with a higher heat resistant cladding with lower enthalpy release rate may also provide additional coping time for accident management. Such a heat resistant cladding may also overcome the current licensing concerns about Zr-alloy hydriding and post quench ductility issues in a design base loss of coolant accident (LOCA). Zr-alloy cladding, while has been optimized for normal operation in high pressure water and steam of light water reactors, will rapidly lose its corrosion resistance and tensile and creep strength in high pressure steam. Evaluation of alternate cladding materials and designs have been performed to search for a new fuel cladding design which will substantially improve the safety margins at elevated temperatures during a severe accident, while maintaining the excellent fuel performance attributes of the current Zr-alloy cladding. The screening criteria for the evaluation include neutronic properties, material availability, adaptability and operability in current LWRs, resistance to melting. The new designs also need to be fabricable, maintain sufficient strength and resist to attack by high pressure steam. Engineering metals, alloys and ceramics which can meet some or most of these requirements are limited. Following review of the properties of potential candidates, it is concluded that molybdenum alloys may potentially achieve the largest improvement in fuel safety margins in a severe accident. To adopt molybdenum alloys for LWR fuel cladding application, a novel design of duplex and triplex Mo-Zr or Mo-advanced steel cladding is proposed as the best candidate for further development. The technical basis for selecting the Mo-Zr cladding out of several other potential candidates, and the approaches to overcome the weakness of the molybdenum alloys are discussed. (orig.)

  9. Quality of the KhN73MBTYu alloy after electroslag remelting and vacuum arc remelting

    International Nuclear Information System (INIS)

    The structure and properties of the heat-resisting KhN73MBTYu alloy are investigated after electroslag remelting (ESR) and vacuum arc (VAR) remelting in commercial furnaces. The complex investigations of the casted metal were carried out by modern methods along with the standard acceptance tests, and a number of service properties were determined. It is established that the ESR metal contains magnesium and has the reduced sulphur concentration; the alloy has more fine-grained structure at high isotropy of the properties at room and operating temperatures; higher endurance is achieved under reversal rotational bending; no laminated fractures are observed. According to the basic quality factors the ESR metal satisfies all requirements for the VAR metal. Due to exclusion of strippling of ESR electrodes and ingots the yield of steel forgings increases by 20-25% and the prime cost decreases in comparison with the industrial production of VAR metal

  10. Electron beam melt-hardening of aluminium alloys

    International Nuclear Information System (INIS)

    In the first stage of the project, the binary alloys AlFe8, AlFe6, AlNi6, AlMn6, AlCr6, AlTi1,5 and AlZr1,5 were systematically melted and solidified. The technological testing has shown that especially the AlFe alloys, after localized melting and rapid solidification, have extremely good tensile strengths which at temperatures of between 200 and 3000C exceed all known heat resistant aluminium alloys. Two alternative methods have been investigated, namely superficial melting of a thin surface layer and a complete melt-hardening. As economic factors favour the use of the EB method for improvement of the surface properties, stages II and III of the project were concerned with the surface hardening of conventional aluminium materials (G-AlCu4Ti, G-AlSi8Cu3) by introducing an additional metal (Fe, Ni) along with the electron beam. The result is that one obtains a surface layer between 1 - 1.5 mm with an average hardness between 200 and 230 HV. Technological laboratory tests have shown that in this manner it is possible to obtain aluminium materials which possess a high wear resistance. (orig.)

  11. Scorpion Venom Heat-Resistant Peptide (SVHRP) Enhances Neurogenesis and Neurite Outgrowth of Immature Neurons in Adult Mice by Up-Regulating Brain-Derived Neurotrophic Factor (BDNF)

    Science.gov (United States)

    Zhang, Yue; Wu, Xue-Fei; Peng, Yan; Cao, Zhen; Ge, Bi-Ying; Wang, Xi; Wu, Qiong; Lin, Jin-Tao; Zhang, Wan-Qin; Li, Shao; Zhao, Jie

    2014-01-01

    Scorpion venom heat-resistant peptide (SVHRP) is a component purified from Buthus martensii Karsch scorpion venom. Although scorpions and their venom have been used in Traditional Chinese Medicine (TCM) to treat chronic neurological disorders, the underlying mechanisms of these treatments remain unknown. We applied SVHRP in vitro and in vivo to understand its effects on the neurogenesis and maturation of adult immature neurons and explore associated molecular mechanisms. SVHRP administration increased the number of 5-bromo-2’-dexoxyuridine (BrdU)-positive cells, BrdU- positive/neuron-specific nuclear protein (NeuN)-positive neurons, and polysialylated-neural cell adhesion molecule (PSA-NCAM)-positive immature neurons in the subventricular zone (SVZ) and subgranular zone (SGZ) of hippocampus. Furthermore immature neurons incubated with SVHRP-pretreated astrocyte-conditioned medium exhibited significantly increased neurite length compared with those incubated with normal astrocyte-conditioned medium. This neurotrophic effect was further confirmed in vivo by detecting an increased average single area and whole area of immature neurons in the SGZ, SVZ and olfactory bulb (OB) in the adult mouse brain. In contrast to normal astrocyte-conditioned medium, higher concentrations of brain-derived neurotrophic factor (BDNF) but not nerve growth factor (NGF) or glial cell line-derived neurotrophic factor (GDNF) was detected in the conditioned medium of SVHRP-pretreated astrocytes, and blocking BDNF using anti-BDNF antibodies eliminated these SVHRP-dependent neurotrophic effects. In SVHRP treated mouse brain, more glial fibrillary acidic protein (GFAP)-positive cells were detected. Furthermore, immunohistochemistry revealed increased numbers of GFAP/BDNF double-positive cells, which agrees with the observed changes in the culture system. This paper describes novel effects of scorpion venom-originated peptide on the stem cells and suggests the potential therapeutic values of SVHRP. PMID:25299676

  12. Investigation of the structure of oxide scales on high temperature alloys using the glow discharge optical spectrometry

    International Nuclear Information System (INIS)

    The depth profiles of the chemical composition of the oxide scales on the high temperature alloys INCONEL alloy 617, HASTELLOY alloy X and INCOLOY alloy 800H were investigated by means of glow discharge optical spectrometry (GDOS). Due to the bombardment of the sample surface with energetic Ar ions, the scale was removed layer by layer. The sputtered species were excited to optical emission in the discharge plasma. Qualitative intensity-time curves were measured by time resolved registration of the intensity of characteristic emission lines for all elements of interest. The quantification of these curves, i.e. the conversion of the intensity into the elemental concentration and of the time into the depth, was the focus of this work. Mathematical correlations between the intensity of an emission line and the corresponding number of atoms in the plasma and the electrical discharge parameters are discussed in detail. An equation for the conversion of the emission line intensity into the elemental concentration was derived by direct measurement of the crater geometry as well as by the determination of the sputtering rate. It is shown that under identical discharge voltage and current the emission yield per atom does not depend on either the matrix from which it is sputtered or the bonding state of the atom. The results of the quantitative GDOS depth analyses were compared with those obtained by means of SIMS, SNMS, EPMA, metallography and x-ray phase analyses. Differences were discussed. (orig.)

  13. Heat resistance of allograft tissue.

    Science.gov (United States)

    Shimp, Larry

    2008-12-01

    Lyophilized allograft musculoskeletal tissue is generally intended to be stored at "ambient" or "room" temperature, and usually is kept in climate controlled indoor storage areas. However, there is a question of what temperature extremes tissue may see, especially during transportation, in that these extremes may exceed even the limits of "ambient" conditions. Temperatures may become quite hot, but only for a few hours and only during daytime. Damage from high temperatures, if it occurs, is expected to be evident by damage to the collagen component of bone, soft tissue, and demineralized bone, as well as to the growth factors contained in demineralized bone. If damage is significant, then temperature monitoring requirements for lyophilized allograft tissue might be necessary. To answer this question, a literature review was carried out to look at the short-term temperature resistance of collagen and demineralized bone. Both collagen and the growth factors in demineralized bone show remarkable short term tolerance to elevated temperatures in the dry state, and it was concluded that temperature excursions of 50 degrees C or less, lasting for a few days or less, would not cause any significant deterioration. This means that temperature monitoring also should not be required. PMID:18340551

  14. Effect of Mg-Zn-Nd spherical quasi-crystals on microstructure and mechanical properties of ZK60 alloy

    Directory of Open Access Journals (Sweden)

    Zhang Jinshan

    2011-08-01

    Full Text Available To improve the strength, toughness, heat-resistance and deformability of magnesium alloy, the microstructure and mechanical properties of ZK60 alloy strengthened by Mg-Zn-Nd spherical quasi-crystal phase (I-phase particles were investigated. Mg40Zn55Nd5 (I-phase particles in addition to ?-Mg, MgZn phase and MgZn2 phases can be obtained in ZK60-based composites under normal casting condition by the addition of quasi-crystal containing Mg-Zn-Nd master alloy. The experimental results show that the introduction of Mg-Zn-Nd spherical quasi-crystal phase into ZK60 alloy makes a great contribution to the refinement of the matrix microstructures and the improvement of mechanical properties. While adding Mg-Zn-Nd spherical quasi-crystal master alloy of 4.0wt.%, the ultimate tensile strength and yield strength of ZK60-based composite at ambient temperature reach their peak values of 256.7 MPa and 150.4 MPa, which were about 17.8% and 24.1% higher respectively than those of the ZK60 alloy. The improved mechanical properties are mainly attributed to the pinning effect of the quasi-crystal particles (I-phase at the grain boundaries. This research results provide a new way for strengthening and toughening of magnesium alloys as well as a new application of Mg-based spherical quasi-crystals.

  15. Amorphous alloys for brazing copper based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Serban, V A; Codrean, C; Utu, D; Opris, C, E-mail: serban@mec.upt.r [Politehnica University of Timisoara, Department for Materials Science and Welding, 1, M. Viteazu Bvd., 300222, Timisoara (Romania)

    2009-01-01

    Silver based alloys are used widely when brazing copper based alloys. Due to its high cost, researchers try to obtain silver free brazing alloys, in the shape of amorphous structure ribbons, avoiding thus the formation of intermetallic compounds that diminish its ductility and plasticity. In this paper, the authors present their results in trying to obtain brazing alloys from the Cu-Zn-Ni-P family, ribbon shaped with amorphous structure, using the melt spinning method. The amorphous character of the processed alloy is emphasized by X-Ray diffraction, and the brazed joints made with the alloy were submitted to metallographic analysis and shearing tests.

  16. Amorphous alloys for brazing copper based alloys

    International Nuclear Information System (INIS)

    Silver based alloys are used widely when brazing copper based alloys. Due to its high cost, researchers try to obtain silver free brazing alloys, in the shape of amorphous structure ribbons, avoiding thus the formation of intermetallic compounds that diminish its ductility and plasticity. In this paper, the authors present their results in trying to obtain brazing alloys from the Cu-Zn-Ni-P family, ribbon shaped with amorphous structure, using the melt spinning method. The amorphous character of the processed alloy is emphasized by X-Ray diffraction, and the brazed joints made with the alloy were submitted to metallographic analysis and shearing tests.

  17. Nature of high hardness in the Co70Mo30 alloy

    International Nuclear Information System (INIS)

    The Co70Mo30 alloy structure formed at different temperatures was studied by means of transmission electron microscopy and photoelectron spectroscopy. It has been found that at temperatures below the solidus temperature the alloy has a tendency toward phase separation which leads to formation of a quasi-cellular microstructure in the form of clusters strongly enriched in Mo and Co, respectively, but existing within a common fcc lattice of the solvent. At low temperatures, an allotropic phase transition ?-Co ? ?-Co occurs in the alloy and the strain contrast, arising at such transitions is superimposed on the quasi-cellular structure. The Co70Mo30 alloy acquires high hardness due to the fact that the crystal lattice in the clusters strongly enriched in Mo remains face-centered. -- Highlights: ? Below the solidus temperature, a tendency toward phase separation leads to a fine-dispersed cellular structure. ? Due to high dispersity, a phase separation occurs only by chemical composition within a single Ni crystal lattice. ? The presence of Mo clusters within the Co crystal lattice determines the high-level strength of the alloy. ? Preservation of the phase separation structure right up to the solidus temperature determines the high heat resistance. ? Clusters strongly enriched in Co are responsible for ?-Co. ? ?-Co transition at 532 °C in the whole volume.

  18. The effect of aging treatment on the high temperature fatigue strength and fatigue fracture behaviour of friction welded domestic heat resisting steels (SUH3-SUS303)

    International Nuclear Information System (INIS)

    In this study the experiment was carried out as the high temperature rotary bending fatigue testing under the condition of 7000C high temperature to the friction welded domestic heat resisting steels, SUH3-SUS303, which were 10 hr., 100 hr. aging heat treated at 7000C after solution treatment 1 hr. at 10600C for the purpose of observing the effects of the high temperature fatigue strength and fatigue fracture behaviours as well as with various mechanical properties of welded joints. The results obtained are summarized as follows: 1) Through mechanical tests and microstructural examinations, the determined optimum welding conditions, rotating speed 2420 rpm, heating pressure 8 kg/mm2, upsetting pressure 22 kg/mm2, the amount of total upset 7 mm (heating time 3 sec and upsetting time 2 sec) were satisfied. 2) The solution treated material SUH3, SUS303 and SUH3-SUS303, have the highest inclination gradiant on S-N curve due to the high temperature fatigue testing for long time at 7000C. 3) The optimum aging time of friction welded SUH3-SUS303, has been recognized near the 10 hr. at 7000C after the solution treatment of 1 hr. at 10600C. 4) The high temperature fatigue limits of aging treated materials were compared with those of raw material according to the extender of aging time, on 10 hr. aging, fatigue limits were increased by SUH3 75.4%, SUS303 28.5%, friction welded joints SUH3-SUS303 28.5%, friction welded joints SUH3-SUS303 44.2% and 100 hr. aging the rate were 64.9%, 30.4% and 36.6% respectively. 5) The fatigue fractures occurred at the side of the base metal SUS303 of the friction welded joints SUH3-SUS303 and it is difficult to find out fractures at the friction welding interfaces. 6) The cracking mode of SUS303, SUH3-SUS303 is intergranular in any case, but SUH3 is fractured by transgranular cracking. (author)

  19. Mechanical alloying of elevated-aluminum alloys

    International Nuclear Information System (INIS)

    An evaluation is made of the properties obtainable in elevated service temperature Al alloys through mechanical alloying methods which encompass reaction-milling of rapidly-solidified powders. The elevated-temperature applications for such alloys are found in turbine engine compressors and internal combustion engine components. Attention is given to AlFeCe and AlSi compositions, as well as to the ultimate tensile strength of extrusions of such compositions as a function of carbon and oxygen content. It is found that the Si content of alloys can be raised by mechanical alloying beyond levels typical of gas atomization processing of powders. 7 refs

  20. Promising technologies for the surface treatment at production and repair of Ti alloys vanes of gas turbine engines with the help of power ion and electron beams

    International Nuclear Information System (INIS)

    By means of AES, SEM, TEM, X-ray diffraction, exoelectron emission as well as by optical metallography in polarized light physical and chemical properties of the surface layers of heat-resistant Ti-based alloys (VT6, VT8, VT9) for application in aviation gas turbine engines exposed to power pulsed ion and electron beams have been investigated. A comparative fatigue tests as well as corrosion and erosion ones of initial serial and irradiated turbine blades were carried out. Perspective fields for the pulsed ion and electron beams application are chosen

  1. Structure stable alloy for large-sized equipment of high temperature gas cooled reactor with coolant temperature of 950 deg. C

    International Nuclear Information System (INIS)

    The material selection for high temperature gas cooled reactor is determined by the requirements of processing, structure stability, heat resistance. For the production of high temperature heat exchanger components for reactor nuclear system BF-400 of 1060 MW heat power, 1100 semi finished items are called for, ranging from 14x2 mm tubes to 2200x150 mm shells. The material must serve for 5.104-2,5.105 hours at the temperature up to 950 deg. C. A detailed description of the XH55MB alloy and test results are shown

  2. Study of cutting speed on surface roughness and chip formation when machining nickel-based alloy

    International Nuclear Information System (INIS)

    Nickel- based alloy is difficult-to-machine because of its low thermal diffusive property and high strength at higher temperature. The machinability of nickel- based Hastelloy C-276 in turning operations has been carried out using different types of inserts under dry conditions on a computer numerical control (CNC) turning machine at different stages of cutting speed. The effects of cutting speed on surface roughness have been investigated. This study explores the types of wear caused by the effect of cutting speed on coated and uncoated carbide inserts. In addition, the effect of burr formation is investigated. The chip burr is found to have different shapes at lower speeds. Triangles and squares have been noticed for both coated and uncoated tips as well. The conclusion from this study is that the transition from thick continuous chip to wider discontinuous chip is caused by different types of inserts. The chip burr has a significant effect on tool damage starting in the line of depth-of-cut. For the coated insert tips, the burr disappears when the speed increases to above 150 m/min with the improvement of surface roughness; increasing the speed above the same limit for uncoated insert tips increases the chip burr size. The results of this study showed that the surface finish of nickel-based alloy is highly affected by the insert type with respect to cutting speed changes and its effect on chip burr formation and tool failuree

  3. Phase and structural transformations in the Ni65Mo20Cr15 alloy at changing the temperature of heat treatment

    International Nuclear Information System (INIS)

    Highlights: • Crystalline Mo particles are formed in liquid alloy as a result of phase separation. • Below 1200 °C the high-dispersed phase separation structure forms in the Ni/Cr pair. • Below 1200 °C the Mo particles are dissolved in the Ni/Mo diffusional couple. • Prolonged 650 °C aging causes the Ni2Mo formation in boundaries and embrittlement. -- Abstract: The ternary Ni65Mo20Cr15 alloy was studied using TEM after heat treatment at different temperatures. It has been shown that the tendency to phase separation which exists in the Ni/Mo diffusion couple at high temperatures leads to precipitation of crystalline particles of Mo atoms in the liquid solution. At lowering the heat treatment temperature to 1200 °C, a phase transition ordering – phase separation occurs in the Ni/Mo diffusion couple, which results in dissolution of the particles of Mo atoms. At 650 °C, there takes place precipitation of Ni2Mo phase particles, which can initiate intercrystalline embrittlement of Hastelloy-type alloys

  4. Effect of Al added to a NiCrMo alloy on the development of the oxide layer of intermetallic coatings

    International Nuclear Information System (INIS)

    Components performance in different environment is strongly dependent on oxides that develop on their surfaces. This study analyzed the oxide layer that develops on coatings processed with mixtures of an atomized Hastelloy C alloy with Al powders. Powder mixtures containing 10, 20 and 30wt%Al were deposited on AISI 1020 and AISI304 steel plates. Coatings were subsequently exposed to 850 deg C for two hours in a low PO2 environment. X-ray diffraction was used to identify the phases that developed in the coating during processing and Raman analysis and Scanning Electron Microscopy were used to characterize the oxide layers. The results showed that coatings processed with the richer Al mixtures, 30wt%Al, which developed NiAl aluminides, reduced the development of ? alumina when processing was done on AISI 304. Coatings processed on AISI 1020 with the three powder mixtures tested developed the different allotropic forms of alumina, as predicted for the tested temperature. (author)

  5. International research cooperation in fiscal 1997. Report on the development of novel magnesium alloy-base ultralight materials; 1997 nendo kokusai kenkyu kyoryoku jigyo. Magnesium gokin ni yoru chokeiryo shinzairyo no kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    Research and development are conducted for the improvement of magnesium alloy characteristics and for the realization of energy and cost saving in the manufacturing process of the said alloys. Concerning manufacturing techniques for high-performance magnesium materials which are among the existing alloys, researches are conducted about the development of superplastic magnesium alloys, development of heat-resistant magnesium alloys, pulverizing techniques and the experimental construction of equipment therefor, safety of magnesium powder, high-precision strain control, processing for enhanced strength and superplasticity, and heat treatment and surface treatment technologies. In the efforts for developing technologies for manufacturing ultrahigh-performance magnesium materials which are novel alloys, researches are conducted concerning the manufacture of amorphous magnesium alloys and methods for evaluating the characteristics thereof, manufacture of amorphous magnesium alloys by a liquid-aided rapid cooling method and the characteristics of the products, and methods for forming the alloys into wires. The developed magnesium materials are tested for strength, resistance to corrosion, etc., and environmental impacts and friendliness toward environments that will eventually affect the life cycle of the new materials are discussed. 45 refs., 91 figs., 21 tabs.

  6. Nitrogen hardening of creep-resistant G-NiCr28W alloy

    Directory of Open Access Journals (Sweden)

    Z. Pirowski

    2010-07-01

    Full Text Available In the group of creep-resistant materials, most important are heat-resistant nickel-based alloys. The G-NiCr28W alloy subject to detailed examinations was observed to have two different austenite-like phases. In the interdendritic spaces of alloy matrix, the presence of another phase, also characterised by paramagnetic properties, was detected. Inside this interdendritic phase, local areas of a lamellar structure, composed of both of the above mentioned phases, were present. Nitrogen treatment was observed to raise the microhardness of both these phases.The presence of nitrogen made the regions of a lamellar structure disappear completely. Their place was occupied by precipitates dispersed in the matrix, and occasionally forming large clusters.It has been observed that cold work can harden the G-NiCr28W alloy to a very small degree only, in spite of the fact that hardness isincreasing systematically with the increasing degree of cold work. The said alloy, when enriched with nitrogen added as an alloyingelement, is characterised by hardness higher than the hardness of its nitrogen-free counterpart. The value of hardness is increasing evenmore under the effect of low-degree cold work, although increasing further the degree of cold work seems to have no effect on hardnessincrease. The problem faced in nickel-based materials is the possibility of making defect-free castings from alloys with high nitrogen content. Alloys investigated in the present study were remelted, cast and subject to solidification under high nitrogen pressure in the furnace chamber. However, melting carried out under these conditions could not prevent the occurrence of non-metallic inclusions which, while being unable to pass to a riser, formed local clusters or even thin films, resulting in numerous microcracks or discontinuities encompassing large regions of the casting. This problem seems to be of major concern and is the first one to require prompt solution in the currently executed large research project.

  7. Corrosion resistance of Ni-Cr-Mo alloys. Chemical composition and metallurgical condition's effects

    International Nuclear Information System (INIS)

    Ni-Cr-Mo alloys offer an outstanding corrosion resistance in a wide variety of highly-corrosive environments. This versatility is due to the excellent performance of nickel in hot alkaline solutions and the beneficial effect of chromium and molybdenum in oxidizing and reducing conditions, respectively. Alloy C-22 (22 % Cr-13 % Mo-3% W) is a well known versatile member of this family. Due to its excellent corrosion resistance in a wide variety of environments, Alloy C-22 has been selected for the fabrication of the corrosion-resistant outer shell of the high-level nuclear waste container. The increasing demand of the industry for corrosion resistant alloys with particular properties of corrosion and mechanical resistance has led to the development of new alloys. Alloy C-22HS (Ni-21 % Cr-17 % Mo) is a new high-strength corrosion resistant material recently developed and introduced into the market. This alloy provides a corrosion resistance comparable with that of other C-type alloys, and it can also be age hardened to effectively double its yield strength. HASTELLOY HYBRID-BC1 (Ni-22 % Mo-15 % Cr) is a new development intended for filling the gap between Ni-Mo and Ni-Cr-Mo alloys. This novel alloy is able to withstand HCl and H2SO4, even in the presence of dissolved oxygen and other oxidizing species. Its resistance to chloride-induced pitting corrosion, crevice corrosion and stress corrosion cracking is also remarkable. Thermal aging of Ni-Cr-Mo alloys leads to microstructure changes depending on the temperature range and exposure time at temperature. A Long Range Ordering (LRO) reaction can occur in the range of 350 C degrees to 600 C degrees, producing an ordered Ni2(Cr,Mo) phase. This ordering reaction does not seem to affect the corrosion resistance and produces only a slight loss in ductility. LRO transformation is homogeneous and has proven to be useful to fabricate the age-hard enable Alloy C22-HS. Tetrahedral Close Packed (TCP) phases, like ?, ? and P, may form if Ni-Cr-Mo alloys are exposed for tens of hours in the range of 600 C degrees to 1100 C degrees. These phases could have a detrimental effect upon corrosion resistance and cause a loss of mechanical ductility. The precipitation of TCP phases starts at grain boundaries and for long aging times it progresses to twins boundaries and then the grain bodies. TCP phases are rich in Mo and Cr. Zones in the matrix adjacent to the TCP precipitates may be depleted of Cr and Mo, and the alloy becomes sensitized.The aim of the present work was to compare the general corrosion rate and the crevice corrosion susceptibility of alloys C-22, C-22HS and HYBRID-BC1 in different metallurgical conditions when exposed to hot chloride solutions. The effects of the alloy composition and different heat treatments were assessed. (author)

  8. A study on fretting fatigue life in elevated temperature for Inconel 600 alloy

    International Nuclear Information System (INIS)

    The safety needs in the operation of nuclear power plant facilities have been increased due to the high temperature and pressure operation conditions within these facilities. Several reports exist on the fretting occurring in the materials of steam generator tubes used in nuclear power plants, which leads to a lower service life. The Inconel 600 alloy, used in steam generator tubes, is a type of nickel-chromium based heat resistant alloy. However, it is necessary to establish a systematic database to guarantee its integrity because there are few data indicating fretting fatigue behaviors at both room and high temperature conditions for the Inconel 600 alloy. Thus, this study analyzed the change in the fatigue characteristics of the Inconel 600 alloy under fretting fatigue by applying plain and fretting fatigue tests at 320 .deg. C, which is the room and actual operating temperature applied to the materials of steam generator tubes. In addition, this study measured the change in the friction force for repetitive cycles in fretting fatigue tests and analyzed the mechanism of fretting fatigue by observing the fracture surfaces.

  9. Effect of coating and surface modification on the corrosion resistance of selected alloys in supercritical water

    International Nuclear Information System (INIS)

    Materials selection is one of the key tasks in Gen-IV reactor development. There is no known material that can meet the expected core outlet conditions of the Canadian SCWR concept (625oC core outlet temperature). High-Cr steels with excellent corrosion resistance are often susceptible to embrittlement due to the precipitation of sigma and other phases in the microstructure. Low-Cr steels such as P91 and oxide dispersion strengthened (ODS) steels exhibit good high-temperature mechanical properties, but the lack of sufficient Cr content makes this group alloy corrode too fast. Improvement in this alloy is needed in order for it to be considered as a piping construction material. In this report, the development of a metallic coating on a P91 substrate is discussed. Recent effort on selection of in-core cladding alloys has focused on heat-resistant 3xx series stainless steels. These alloys have higher strength at high-temperature ranges, but corrosion and stress-corrosion cracking resistance are a concern. Metallic coating and surface modification are considered as possible solutions to overcome this challenge. The effects of surface modification on the corrosion rate of austenitic steels were also reported in this paper. As-machined surface showed much better corrosion resistance than polished surface and advanced surface analyses showed distinct differences in the nature and the morphology of the surface layer metal. Possible mechanisms for improved corrosion performance are discussed. (author)

  10. Effect of coating and surface modification on the corrosion resistance of selected alloys in supercritical water

    Energy Technology Data Exchange (ETDEWEB)

    Li, J.; Zheng, W. [CANMET, Materials Technology Lab., Hamilton, Ontario (Canada); Cook, W. [Univ. of New Brunswick, Fredericton, New Brunswick (Canada); Toivonen, A.; Penttila, S. [VTT Technical Research Center of Finland, Espoo (Finland); Guzonas, D.; Woo, O.T. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Liu, P.; Bibby, D. [CANMET, Materials Technology Lab., Hamilton, Ontario (Canada)

    2011-07-01

    Materials selection is one of the key tasks in Gen-IV reactor development. There is no known material that can meet the expected core outlet conditions of the Canadian SCWR concept (625{sup o}C core outlet temperature). High-Cr steels with excellent corrosion resistance are often susceptible to embrittlement due to the precipitation of sigma and other phases in the microstructure. Low-Cr steels such as P91 and oxide dispersion strengthened (ODS) steels exhibit good high-temperature mechanical properties, but the lack of sufficient Cr content makes this group alloy corrode too fast. Improvement in this alloy is needed in order for it to be considered as a piping construction material. In this report, the development of a metallic coating on a P91 substrate is discussed. Recent effort on selection of in-core cladding alloys has focused on heat-resistant 3xx series stainless steels. These alloys have higher strength at high-temperature ranges, but corrosion and stress-corrosion cracking resistance are a concern. Metallic coating and surface modification are considered as possible solutions to overcome this challenge. The effects of surface modification on the corrosion rate of austenitic steels were also reported in this paper. As-machined surface showed much better corrosion resistance than polished surface and advanced surface analyses showed distinct differences in the nature and the morphology of the surface layer metal. Possible mechanisms for improved corrosion performance are discussed. (author)

  11. Hydrofluoric Acid Corrosion Study of High-Alloy Materials

    International Nuclear Information System (INIS)

    A corrosion study involving high-alloy materials and concentrated hydrofluoric acid (HF) was conducted in support of the Molten Salt Reactor Experiment Conversion Project (CP). The purpose of the test was to obtain a greater understanding of the corrosion rates of materials of construction currently used in the CP vs those of proposed replacement parts. Results of the study will help formulate a change-out schedule for CP parts. The CP will convert slightly less than 40 kg of 233U from a gas (UF6) sorbed on sodium fluoride pellets to a more stable oxide (U3O8). One by-product of the conversion is the formation of concentrated HF. Six moles of highly corrosive HF are produced for each mole of UF6 converted. This acid is particularly corrosive to most metals, elastomers, and silica-containing materials. A common impurity found in 233U is 232U. This impurity isotope has several daughters that make the handling of the 233U difficult. Traps of 233U may have radiation fields of up to 400 R at contact, a situation that makes the process of changing valves or working on the CP more challenging. It is also for this reason that a comprehensive part change-out schedule must be established. Laboratory experiments involving the repeated transfer of HF through 1/2-in. metal tubing and valves have proven difficult due to the corrosivity of the HF upon contact with all wetted parts. EacHF upon contact with all wetted parts. Each batch of HF is approximately 1.5 L of 33 wt% HF and is transferred most often as a vapor under vacuum and at temperatures of up to 250 C. Materials used in the HF side of the CP include Hastelloy C-276 and Monel 400 tubing, Haynes 230 and alloy C-276 vessels, and alloy 400 valve bodies with Inconel (alloy 600) bellows. The chemical compositions of the metals discussed in this report are displayed in Table 1. Of particular concern are the almost 30 vendor-supplied UG valves that have the potential for exposure to HF. These valves have been proven to have a finite life due to failure, most often at the bellows flange ring. It was discovered that the entire bellows assembly was not all alloy 600 but that alloy 600 bellows had been welded to a stainless steel alloy 316 (SS-316) flange ring. A previous study documents and addresses this problem.1 The fabricators of the valves immediately corrected the problem and began fabricating all wetted parts of the bellows assembly from alloy 600. At the same time, the fabricators began to make alloy C-276 valve bodies and stem tips available for sale. This material is known to be superior to the alloy 400 valve bodies and stem tips of the standard UG valves that had already been installed in the CP. A decision was made to purchase alloy C-276 bodies and stem tips and to change out those alloy 400 components that had already been installed. Due to the enormity of this task (both in terms of time and money), it was desirable to determine the longevity of alloy C-276 vs alloy 400 components in a side-by-side comparison. Also of interest was the question of how long the new (all-alloy 600) bellows would last in comparison with the original alloy 600/SS-316 bellows. A basic HF corrosion test was proposed to compare corrosion rates of several high-alloy materials. Because much of the alloy 400 in the system had been gold plated, some gold-plated alloy 400 coupons were included. Due to time and funding limitations, actual CP variables such as temperature and pressure were not duplicated. Instead, a simple partial-immersion test at ambient temperature was conducted. The purpose of this test was to gain information on the rate of corrosion of different alloys in the CP and to attempt to derive some idea of their expected lifetimes in the operating environment

  12. Mechanical properties of pure Ni and Ni-alloy substrate materials for Y Ba Cu O coated superconductors

    Science.gov (United States)

    Clickner, C. C.; Ekin, J. W.; Cheggour, N.; Thieme, C. L. H.; Qiao, Y.; Xie, Y.-Y.; Goyal, A.

    2006-06-01

    Mechanical properties of rolling-assisted, biaxially-textured substrates (RABiTS) and substrates for ion-beam assisted deposition (IBAD) coated superconductors are measured at room temperature, 76, and 4 K. Yield strength, Young's modulus, and the proportional limit of elasticity are determined, tabulated and compared. Results obtained are intended to serve as a database of mechanical properties of substrates having the same anneal state and texture as those incorporated in the general class of RE-Ba-Cu-O coated conductor composites (RE = rare earth). The RABiTS materials measured are pure Ni, Ni-13at.%Cr, Ni-3at.%W-2at.%Fe, Ni-10at.%Cr-2at.%W, and Ni-5at.%W. The IBAD substrate materials included Inconel 625 and Hastelloy C-276. The Ni alloys are substantially stronger and show higher strains at the proportional limit than those of pure Ni. Substrates fully coated with buffer layers, ?1 ?m of Y-Ba-Cu-O, and 3-5 ?m of Ag have similar mechanical properties (at 76 K) as the substrate alone. Somewhat surprisingly, plating an additional 30-40 ?m of Cu stabilizer onto high-yield-strength (690 MPa) Hastelloy coated conductors ˜100 ?m thick, reduces the overall yield strength of the composite structure by only about 10-12% at 76 K and 12-14% at room temperature; this indicates that the Cu layer, despite its relatively soft nature, contributes significantly to the overall strength of even high-strength coated conductors.

  13. Effect of composition and structure on crevice, intergranular, and stress corrosion of some wrought Ni--Cr--Mo alloys

    International Nuclear Information System (INIS)

    The relationship of composition and microstructure to the occurrence of localized corrosion in Hastelloy alloys C, C-276, and C-4 was investigated. One hour exposures of these alloys in the range of 1200 to 22000F may result in the formation of a molybdenum-rich intermetallic compound and, in alloys with more than about 0.004 percent C, a molybdenum-rich carbide. The boiling ferric sulfate-50 percent H2SO4 test readily detects the presence of both of these precipitates which cause rapid intergranular attack in this solution. The molybdenum-rich M6C carbide precipitate impairs resistance to intergranular, crevice, and stress corrosion. In contrast, the molybdenum-rich intermetallic compound, Mo-phase impairs resistance only to intergranular attack, primarily in oxidizing acids. When the carbon content is progressively increased above 0.004 percent, formation of the molybdenum-rich carbide precipitate at grain boundaries by one hour heat treatment results first in loss of resistance to stress corrosion cracking (SCC) in the boiling 45 percent MgCl2 test. Further increases in carbon content (0.05 percent) result in loss of resistance to intergranular attack in acids, to crevice corrosion in 10 percent ferric chloride at 500C and also to SCC in this solution. All SCC is of the intergranular type. Formation of the molybdenum-rich carbide precipitate is prevented in alloy C-4 by keeping the carbon content lowlloy C-4 by keeping the carbon content low and by addition of titanium. Formation of the intermetallic compound is minimized by adjustment of the alloy content. In the heat investigated, titanium stabilization was effective in preventing intergranular attack in reducing acids and SCC in the MgCl2 test. However, metallographic examination and intergranular attack in the ferric sulfate test on material heated 1 hour at 16000F indicated that a compound was still being formed at grain boundaries

  14. Optimization of the Mg-Al-Zn-Ca-Sr alloy composition based on the parameter A Prime in the constitutive equation for the climb-controlled dislocation creep including the stacking fault energy

    Energy Technology Data Exchange (ETDEWEB)

    Hirai, Kinji, E-mail: kinji.hirai@takata.co.jp [Advanced Technologies, Inc., 616-3, Jinba, Gotemba, Shizuoka 412-0047 (Japan); Takeuchi, Ippei; Takigawa, Yorinobu; Uesugi, Tokuteru; Higashi, Kenji [Department of Materials Science, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Sakai 599-8531 (Japan)

    2012-08-15

    In this study, calcium, Ca-, and strontium, Sr-added AZ91 magnesium alloys, which were composed of magnesium, Mg-9 wt.% aluminum, Al-0.8 wt.% zinc, Zn-x wt.% Ca-y wt.% Sr, were formulated and designated as AZXJ91xy alloys. The optimum composition of die-cast AZXJ alloys has been studied by micro-structural analysis and through the application of the constitutive equation of deformation behavior at elevated temperatures that includes the stacking fault energy. The normalized plots of the tensile test results of AZXJ alloys at 448 K by the constitutive equation of deformation behavior indicated that the deformation mechanism of the alloys was climb-controlled dislocation creep. The value of the constant A Prime in the constitutive equation differs in the different AZXJ alloys, even though the effect of the solid solution of added elements, which is considered in the stacking fault energy term, was eliminated from A Prime . Using A Prime as an indicator parameter of the creep resistance with the tensile strength at ambient temperature, the optimum composition of the creep-resistant Mg-Al-Zn-Ca-Sr alloy has been determined, and its creep resistance was comparable to those of known heat-resistant magnesium alloys.

  15. Turbine Blade Alloy

    Science.gov (United States)

    MacKay, Rebecca

    2001-01-01

    The High Speed Research Airfoil Alloy Program developed a fourth-generation alloy with up to an +85 F increase in creep rupture capability over current production airfoil alloys. Since improved strength is typically obtained when the limits of microstructural stability are exceeded slightly, it is not surprising that this alloy has a tendency to exhibit microstructural instabilities after high temperature exposures. This presentation will discuss recent results obtained on coated fourth-generation alloys for subsonic turbine blade applications under the NASA Ultra-Efficient Engine Technology (UEET) Program. Progress made in reducing microstructural instabilities in these alloys will be presented. In addition, plans will be presented for advanced alloy development and for computational modeling, which will aid future alloy development efforts.

  16. A study on fretting fatigue life for the Inconel alloy 600 at high temperature

    International Nuclear Information System (INIS)

    Fatigue tests of the Inconel 600, a type of nickel-chromium based heat resistant alloy used for steam generator tubes in nuclear power plants, were carried out. Temperature increase to 320 oC did not change the fatigue strength much, but the fretting condition caused a significant reduction in the fatigue strength. The reduction at 107 cycles was about 70% for both of room and the high temperatures. An apparatus to realize the fretting condition has been developed and instrumented to measure the normal and friction forces. The bridge type of contact pad was fabricated of SUS 409 stainless steel. Fracture surfaces and wear scars were observed by electron microscope and the profiles of wear scar were measured by non-contact 3D-profiler.

  17. Magnesium alloys alloyed with rare earths

    International Nuclear Information System (INIS)

    Results of investigations into magnesium alloys doped with rare earths are presented. Results of investigations into phase diagrams of magnesium alloys with rare earths are given. Regularities of their structure as regards the solubility in magnesium in the solid state, the nature and temperature non-variant transformations, composition and formation temperatures of chemical compounds, are found out. The effect of rare earths on magnesium mechanical properties and their connection with the structure of alloys are considered. The data are presented which characterize the peculiarities of decomposition of a supersaturated solid solution in alloys of various systems and the effect of hot and cold plastic deformation on decomposition. The data on the compositions and properties of commercial magnesium alloys containing rare earths are presented

  18. High strength alloys

    Science.gov (United States)

    Maziasz, Phillip James; Shingledecker, John Paul; Santella, Michael Leonard; Schneibel, Joachim Hugo; Sikka, Vinod Kumar; Vinegar, Harold J.; John, Randy Carl; Kim, Dong Sub

    2012-06-05

    High strength metal alloys are described herein. At least one composition of a metal alloy includes chromium, nickel, copper, manganese, silicon, niobium, tungsten and iron. System, methods, and heaters that include the high strength metal alloys are described herein. At least one heater system may include a canister at least partially made from material containing at least one of the metal alloys. At least one system for heating a subterranean formation may include a tublar that is at least partially made from a material containing at least one of the metal alloys.

  19. Influence of Mn content on corrosion behavior of Ni-Cr-W alloys in simulated VHTR helium environment

    International Nuclear Information System (INIS)

    The influence of Mn addition up to 3.3 wt% on the corrosion behavior of Ni-21%Cr-15%W alloys was studied. Up to 1.3 wt%, increase of Mn content was found to be beneficial quite simularly to the case of Hastelloy X as already recognized in the previous works. The material is one of the developmental Ni-Cr-W superalloys with excellent high temperature creep strength for future VHTR application. The corrosion tests were carried out at 9000C and 10000C in exposing the materials to simulated VHTR helium for up to 3000 hr. The results obtained are summarized below. (1) The degrees of oxidation resistance and adherence of the oxide film to base metal were maximized with Mn content of around 1 wt%. (2) Addition of Mn of the range 1 to 3.3 wt% did not cause appreciable change in carburization of the alloy at 900 0C. (3) At 10000C, decrease of carburization resistance with increasing Mn content was found to occur. (4) Compromising the results of oxidation and carburization behavior, specifying the addition of 1 wt% Mn was proposed to be an optimum. (author)

  20. Creep Resistant Zinc Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  1. Long-term rupture strength and creep in vanadium alloy V-4Ti-4Cr at temperatures of 500-700 deg C

    International Nuclear Information System (INIS)

    Vanadium base alloy V-4Ti-4Cr is tested to determine as short-term tensile properties in the temperature interval of 20-700 deg C so a creep resistance and a long-term rupture strength at 500, 600, 650 and 700 deg C for testing duration of 200-21000 h. The tests are carried out using cylindrical specimens manufactured from rods produced in turn, from vacuum double-remelted castings. It is stated that a creep strength at a rate of 1 x 10-6 h-1 equals 365 and 137 MPa for temperatures 550 deg C and 700 deg C respectively. A long-term rupture strength at above-mentioned temperatures constitutes 375 and 125 MPa for the duration of testing equal to 10000 h. It is show that the alloy V-4Ti-4Cr is more heat resistant compared to austenitic and ferritic-martensitic steels

  2. Siegel FIRST EXPERIMENTAL DISCOVERY of Granular-Giant-Magnetoresistance (G-GMR) DiagnosES/ED Wigner's-Disease//Spinodal-Decomposition in ``Super''' Alloys Generic Endemic Extant in: Nuclear-Reactors/ Petrochemical-Plants/Jet/ Missile-Engines/

    Science.gov (United States)

    Hoffman, Ace; Wigner-Weinberg, Eugene-Alvin; Siegel, Edward Carl-Ludwig Sidney

    2013-03-01

    Siegel[APS Shock-Physics Mtg., Chicago(11)] carbides solid-state chemistry[PSS (a)11,45(72); Semis. & Insuls. 5: 39,47,62 (79)], following: Weinberg-Siegel-Loretto-Hargraves-Savage-Westwood-Seitz-Overhauser-, FIRST EXPERIMENTAL DISCOVERY of G-GMR[JMMM 7, 312(78); Google: ``If LEAKS Could KILL Ana Mayo''] identifIED/IES GENERIC ENDEMIC EXTANT domination of old/new (so mis-called) ``superalloys'': nuclear-reactors/spent-fuel-casks/refineries/jet/missile/rocket-engines in austenitic/FCC Ni/Fe/Co-based (so mis-called) "super"alloys (182/82; Hastelloy-X,600,304/304L-Stainless-Steels,...,690!!!) GENERIC ENDEMIC EXTANT detrimental(synonyms!!!): THERMAL: Wigner's-disease(WD; physics) [J.Appl.Phys.17,857(46)]/ Ostwald-ripening

  3. Effects of heat treatment processes on microstructure and creep properties of a high nitrogen 15Cr-15Ni austenitic heat resistant stainless steel

    International Nuclear Information System (INIS)

    Highlights: ? CTMT induced elongated clusters of fine (Nb,Cr,Fe)(C,N) particles. ? Hot rolling in MTMT induced evenly distributed fine (Nb,Cr,Fe)(C,N). ? Number and distribution of Cu precipitates not affected by hot rolling. ? Distribution homogeneity of fine (Nb,Cr,Fe)(C,N) promotes creep strength increase. ? Finer grain size structure promotes lower creep ductility. - Abstract: Conventional thermo-mechanical treatment (CTMT) and modified thermo-mechanical treatment (MTMT) process were applied for manufacturing a high nitrogen niobium-stabilized 15Cr-15Ni austenitic alloy. CTMT process consists of 5 h of solution treatment at 1270 deg. C followed by water quenching and subsequent aging at 820 deg. C for 50 h. MTMT process differs from CTMT process in hot plastic deformation performed immediately after the solution treatment at 1270 deg. C and longer aging time. Microstructure and creep properties of the steel obtained by both processing routes were investigated. Creep rupture tests at 750 deg. C showed double increase in rupture time brought about by MTMT process. Examination of crept microstructure by transmission electron microscopy revealed that the improved creep properties in MTMT process were mainly due to improved distribution uniformity of fine nano-sized carbonitride precipitates in the austenitic matrix and that MTMT process has no effects on the number density and distribution of copper precipitates present in the steel. However, the creep ducti steel. However, the creep ductility in MTMT process drastically reduced comparing to CTMT process. The higher density of grain boundaries due to finer grain recrystallized microstructures and the formation of higher volume fraction of coarser M23C6 precipitates at the boundaries are believed to be the main reason for the lower creep ductility in MTMT process.

  4. Martensitic-austenitic 9-12% Cr steels-Alloy design, microstructural stability and mechanical properties

    International Nuclear Information System (INIS)

    This work describes the alloy development of heat-resistant 9-12% chromium steels with a microduplex structure for application in advanced gas or steam turbines. Such alloys feature a two-phase microstructure, consisting of 30 vol.% of austenite in a matrix of tempered martensite with fine precipitates of vanadium nitride. This so-called microduplex structure is formed from a fully martensitic structure during tempering at 575-625 deg. C. The austenite is in lamellar arrangement with a lamella thickness of 100-500 nm and a lamella length of a few microns, parallel to the martensite plates. Within the scope of this work the effect of the individual alloying elements has been investigated both experimentally and by means of thermodynamic calculations using ThermoCalc. The phenomena of austenite formation during tempering and the stability of the austenite against martensitic transformation are described in detail. The high Mn and Ni content is responsible for the formation of the microduplex structure. Very good mechanical properties are achieved, in particular an advantageous combination of strength and toughness, coupled with high creep strength at 550 deg. C. Microduplex steels are therefore promising candidates for the application in energy conversion systems, for example as compressor discs in high-efficiency stationary gas turbines

  5. Aluminum Alloys for High Temperatures

    Science.gov (United States)

    Meschter, Peter J.; Lederich, Richard J.; O'Neal, James E.

    1987-01-01

    New Al/Li alloys processed by rapid solidification show greatly improved strength-to-density ratios. Alloys suitable substitutes for heavier titanium alloys and weaker aluminum alloys in high-performance aircraft, bombers, and transports. Also suitable for use in high-performance-aircraft structures heated by engines and normally constructed from titanium alloys.

  6. The DynAlloy Visualizer

    OpenAIRE

    Bendersky, Pablo; Galeotti, Juan Pablo; Garbervetsky, Diego

    2014-01-01

    We present an extension to the DynAlloy tool to navigate DynAlloy counterexamples: the DynAlloy Visualizer. The user interface mimics the functionality of a programming language debugger. Without this tool, a DynAlloy user is forced to deal with the internals of the Alloy intermediate representation in order to debug a flaw in her model.

  7. Characterization of Alloys with Potential for Application in Cable-in-Conduit Conductors for High-Field Superconducting Magnets

    International Nuclear Information System (INIS)

    Since the introduction of the cable-in-conduit conductor (CICC) concept, a variety of alloys have been proposed for fabricating the jacket. The jacket provides primary containment of the supercritical helium coolant and is typically also the primary structural component for the magnet. These functions create requirements for strength, toughness, weldability, and fabricability in tubular form. When the CICC uses Nb3Sn, there are additional requirements to accommodate the manufacturing and heat-treatment processes for the superconductor as well as its strain-sensitive performance during operation. Both of the present favorite jacket alloys, Incoloy 908 and modified (ultra-low carbon) 316LN, have both demonstrated acceptable functionality as well as a few undesirable features. In this paper, we present data from cryogenic mechanical tests on a group of heat-resistant, high-strength superalloys that appear to offer equal or better mechanical performance (e.g. strength, toughness, and modulus) while mitigating the undesirable aspects (e.g. SAGBO in the case of I908 and thermal-expansion mismatch with Nb3Sn in the case of 316LN). Data are presented for each alloy in the as-received and aged conditions. These alloys are presently being considered as candidates for use in the next-generation hybrid magnet for the NHMFL but may also be of interest to the fusion and energy storage communities

  8. Characterization of Alloys with Potential for Application in Cable-in-Conduit Conductors for High-Field Superconducting Magnets

    Science.gov (United States)

    Walsh, R. P.; Miller, J. R.; Toplosky, V. J.

    2004-06-01

    Since the introduction of the cable-in-conduit conductor (CICC) concept, a variety of alloys have been proposed for fabricating the jacket. The jacket provides primary containment of the supercritical helium coolant and is typically also the primary structural component for the magnet. These functions create requirements for strength, toughness, weldability, and fabricability in tubular form. When the CICC uses Nb3Sn, there are additional requirements to accommodate the manufacturing and heat-treatment processes for the superconductor as well as its strain-sensitive performance during operation. Both of the present favorite jacket alloys, Incoloy 908 and modified (ultra-low carbon) 316LN, have both demonstrated acceptable functionality as well as a few undesirable features. In this paper, we present data from cryogenic mechanical tests on a group of heat-resistant, high-strength superalloys that appear to offer equal or better mechanical performance (e.g. strength, toughness, and modulus) while mitigating the undesirable aspects (e.g. SAGBO in the case of I908 and thermal-expansion mismatch with Nb3Sn in the case of 316LN). Data are presented for each alloy in the as-received and aged conditions. These alloys are presently being considered as candidates for use in the next-generation hybrid magnet for the NHMFL but may also be of interest to the fusion and energy storage communities.

  9. Evaluation of creep-fatigue/ environment interaction in Ni-base wrought alloys for HTGR application

    International Nuclear Information System (INIS)

    High Temperature Gas-cooled Reactor (HTGR) systems should be designed based on the high temperature structural strength design procedures. On the development of design code, the determination of failure criteria under cyclic loading and severe environments is one of the most important items. By using the previous experimental data for Ni-base wrought alloys, Inconel 617 and Hastelloy XR, several evaluation methods for creep-fatigue interaction were examined for their capability to predict their cyclic loading behavior for HTGR application. At first, the strainrange partitioning method, the frequency modified damage function and the linear damage summation rule were discussed. However, these methods were not satisfactory with the above experimental results. Thus, in this paper, a new fracture criterion, which is a modification of the linear damage summation rule, is proposed based on the experimental data. In this criterion, fracture is considered to occur when the sum of the fatigue damage, which is the function of the applied cyclic strain magnitude, and the modified creep damage, which is the function of the applied cyclic stress magnitude (determined as time devided by cyclic creep rupture time reflecting difference of creep damages by tensile creep and compressive creep), reaches a constant value. This criterion was successfully applied to the life prediction of materials at HTGR temperatures. (author)

  10. Catalyst Alloys Processing

    Science.gov (United States)

    Tan, Xincai

    2014-10-01

    Catalysts are one of the key materials used for diamond formation at high pressures. Several such catalyst products have been developed and applied in China and around the world. The catalyst alloy most widely used in China is Ni70Mn25Co5 developed at Changsha Research Institute of Mining and Metallurgy. In this article, detailed techniques for manufacturing such a typical catalyst alloy will be reviewed. The characteristics of the alloy will be described. Detailed processing of the alloy will be presented, including remelting and casting, hot rolling, annealing, surface treatment, cold rolling, blanking, finishing, packaging, and waste treatment. An example use of the catalyst alloy will also be given. Industrial experience shows that for the catalyst alloy products, a vacuum induction remelt furnace can be used for remelting, a metal mold can be used for casting, hot and cold rolling can be used for forming, and acid pickling can be used for metal surface cleaning.

  11. Translating VDM to Alloy

    DEFF Research Database (Denmark)

    Lausdahl, Kenneth

    2013-01-01

    The Vienna Development Method is one of the longest established formal methods. Initial software design is often best described using implicit specifications but limited tool support exists to help with the difficult task of validating that such specifications capture their intended meaning. Traditionally, theorem provers are used to prove that specifications are correct but this process is highly dependent on expert users. Alternatively, model finding has proved to be useful for validation of specifications. The Alloy Analyzer is an automated model finder for checking and visualising Alloy specifications. However, to take advantage of the automated analysis of Alloy, the model-oriented VDM specifications must be translated into a constraint-based Alloy specifications. We describe how a subset of VDM can be translated into Alloy and how assertions can be expressed in VDM and checked by the Alloy Analyzer.

  12. Ferroelectric and ferromagnetic properties of epitaxial BiFeO3-BiMnO3 films on ion-beam-assisted deposited TiN buffered flexible Hastelloy

    International Nuclear Information System (INIS)

    Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO3)0.5:(BiMnO3)0.5 [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La0.7Sr0.3MnO3 (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9??C/cm2. The magnetization of the BFO-BMO/LSMO is 62?emu/cc at room temperature

  13. Ferroelectric and ferromagnetic properties of epitaxial BiFeO{sub 3}-BiMnO{sub 3} films on ion-beam-assisted deposited TiN buffered flexible Hastelloy

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, J., E-mail: jiexiong@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Division of Materials Physics and Applications, Los Alamos, New Mexico 87545 (United States); Matias, V.; Jia, Q. X. [Los Alamos National Laboratory, Center for Integrated Nanotechnologies, Division of Materials Physics and Applications, Los Alamos, New Mexico 87545 (United States); Tao, B. W.; Li, Y. R. [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2014-05-07

    Growth of multifunctional thin films on flexible substrates is of great technological significance since such a platform is needed for flexible electronics. In this study, we report the growth of biaxially aligned (BiFeO{sub 3}){sub 0.5}:(BiMnO{sub 3}){sub 0.5} [BFO-BMO] films on polycrystalline Hastelloy by using a biaxially aligned TiN as a seed layer deposited by ion-beam-assisted deposited and a La{sub 0.7}Sr{sub 0.3}MnO{sub 3} (LSMO) as a buffer layer deposited by pulsed laser deposition. The LSMO is used not only as a buffer layer but also as the bottom electrode of the BFO-BMO films. X-ray diffraction showed that the BFO-BMO films are biaxially oriented along both in-plane and out-of-plane directions. The BFO-BMO films on flexible metal substrates showed a polarization of 22.9??C/cm{sup 2}. The magnetization of the BFO-BMO/LSMO is 62?emu/cc at room temperature.

  14. Amorphous metal alloy

    Science.gov (United States)

    Wang, R.; Merz, M.D.

    1980-04-09

    Amorphous metal alloys of the iron-chromium and nickel-chromium type have excellent corrosion resistance and high temperature stability and are suitable for use as a protective coating on less corrosion resistant substrates. The alloys are stabilized in the amorphous state by one or more elements of titanium, zirconium, hafnium, niobium, tantalum, molybdenum, and tungsten. The alloy is preferably prepared by sputter deposition.

  15. Low activation ferritic alloys

    Science.gov (United States)

    Gelles, David S. (West Richland, WA); Ghoniem, Nasr M. (Granada Hills, CA); Powell, Roger W. (Pasco, WA)

    1986-01-01

    Low activation ferritic alloys, specifically bainitic and martensitic stainless steels, are described for use in the production of structural components for nuclear fusion reactors. They are designed specifically to achieve low activation characteristics suitable for efficient waste disposal. The alloys essentially exclude molybdenum, nickel, nitrogen and niobium. Strength is achieved by substituting vanadium, tungsten, and/or tantalum in place of the usual molybdenum content in such alloys.

  16. Superplasticity in titanium alloys

    OpenAIRE

    Sieniawski, J.; Motyka, M.

    2007-01-01

    Purpose: The paper reports characteristic of superplasticity phenomenon in titanium alloys and possibility of its applications.Design/methodology/approach: The main objective of the paper is to show features of superplastic forming of titanium alloys and current research trends aiming at widespread application of this technology.Findings: In the paper characteristic of selected superplastic titanium alloys was presented. The effect of microstructural parameters on superplasticity was consider...

  17. High strength alloy

    International Nuclear Information System (INIS)

    The magnesium-based alloy in question contains alloy components in the form of elements chosen from the Al, Zn, Mn, Zr and rare earth group, and compounds of nitrogen and oxygen with any of these elements in the following proportions (wt%): alloy components chosen from the Al, Zn, Mn, Zr, Th and rare earth group 0.6-8.0, compound of nitrogen and oxygen with any of the above 0.1-6.0, magnesium the remainder. (author)

  18. Laser boronizing of titanium alloys

    International Nuclear Information System (INIS)

    A study was made on peculiarities of formation of surface layer structure of VT3-1 titanium alloy under laser alloying from slip wats, containing mixture of B4C boron carbide and chromium It was established that laser alloying of titanium alloys by boron carbide and chromium mixture led to formation of highly consistent boronized layers on the surface (even at high B4C contents). Introduction of calcium fluoride into alloying compound promotes sufficient improvement of antifriction properties of alloys

  19. Corrosion resistant amorphous alloys

    International Nuclear Information System (INIS)

    A review of publication data on corrosion resistance of amorphous alloys and the methods of amorphization of surface layers of massive materials (laser treatment, iron implantation, detonation-gas spraying, cathode and ion sputtering, electrodeposition) was made. A study was made on corrosion properties of Fe66Cr11B10Si4 alloy in cast state and after laser irradiation, rendering the surface amorphous as well as the samples of Arenco iron and steel 20 with ion-plasma coatings of Fe-Cr-Ni-Ti alloy. It was established that amorphous coatings posses much higher corrosion resistance as compared to crystalline alloys on the same base

  20. New Methodology to Predict the Long-term Creep Strength of Alloy 617 for a Very High Temperature Reactor

    International Nuclear Information System (INIS)

    Alloy 617 is a prime candidate material for the very high temperature gas-cooed reactor(VHTR) components due to its superior creep resistance above 800 .deg. C when compared to other candidate alloys; Haynes 230, Hastelloy-X and Alloy 800. Considerable creep data for Alloy 617 is available in the literature, and a draft Alloy 617 code case and ASME Boiler and Pressure Vessel (BPV) Code-Section II have also provided allowable stress values for a 105 h design period at temperatures up to 982 .deg. C. However, the creep and oxidation behaviors for Alloy 617 are not well understood yet, and their long-term creep strength should be predicted for use in a design and analysis. So far, Larson-Miller (LM) parameter method known as a time-temperature parameter (TTP) has been the most commonly used to predict the long-term creep life from short-term creep data. TTP constant C in the LM method is unique for a given set of creep rupture data to be analyzed. Temperature dependency of a rupture life, dlogtr /d(1/T), should not change in the data set. But, this assumption is not always valid, because the C for the rupture life changes from a high value of the short term creep to a low value of the long term creep. So, Maruyama et al. have reported that the multi region analysis for Q in Orr-Sherby-Dorn (OSD) parameter could evaluate the long-term rupture of austenite stainless steels and 9-12% Cr steels accurately. However, an overestimation of the long term ruper, an overestimation of the long term rupture in the LM parameter has not been reported for Alloy 617, and furthermore, to avoid it, a multi constant method for the C in the LM parameter has not been demonstrated by others. In this paper, a longer creep life for above 105h at 950 .deg. C was accurately predicted by using a new method with two C values in the LM parameter. Also, oxidation behavior was investigated by using a scanning electron microscope (SEM) and an energy dispersive X-ray spectroscopy (EDX) analysis