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1

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

International Nuclear Information System (INIS)

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

1993-01-01

2

Hydrogen damage of nickel-base heat resistant alloys  

International Nuclear Information System (INIS)

The damage of nickel-base heat resistant alloys exposed to hydrogen at high temperature and pressure was investigated. Tested materials were mainly Inconel 600, Hastelloy X and nickel. Main results obtained are as follows: 1) Inconel 600 solution treated exhibited embrittlement due to the occluded hydrogen. 2) Hastelloy X solution treated did not exhibit embrittlement. 3) Nickel exhibited the irreversible damage although it was completedly dehydrogenated. 4) Stress concentration enlarged the susceptibility to embrittlement. Hastelloy X which did not show embrittlement in a smooth type specimen was also embrittled when stress was concentrated. 5) Embrittlement depended on Ni content and materials with higher Ni content exhibited the irreversible damage. 6) The susceptibility to hydrogen embrittlement of Inconel 600 and Hastelloy X increased when they were aged and carbides were precipitaed on grain boundaries. This effect could be explained by hydrogen trapping. (author)

1979-01-01

3

Carburization of Hastelloy alloy X  

International Nuclear Information System (INIS)

The carburization of Hastelloy X has been studied by the standard tracer techniques using 14C over the temperature range 700 to 11000C in vacuo and helium environment. The 14C activity in the specimen decreases exponentially with the depth of penetration and increases with carburization time. It is observed that carbon diffusion in the alloy is dominated by grain-boundary diffusion. The effect of oxygen in helium gas on carburization is observed. Oxygen has two opposite types of action on carburization of the alloy. One is inhibitive action and the other is accelerative action. (Auth.)

1975-01-01

4

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)

1987-01-01

5

Alloying principles for tungsten heat resisting alloys  

International Nuclear Information System (INIS)

The obtained experimental and literature data on the effect of alloyino. elements on structure, phase composition and properties of tungsten alloys are analysed on the base of which the main alloying principles of heat resistant ductile low-alloyed tuno.sten alloys are formulated. The methods of vacuum melting and powder metallurgy have been applied to prepare the alloys. Complex hardenino.: strain (epsilon > 95%), solid-solution (up to 2% Ta, up to 25-30 weight % molybdenum, rhenium) and precipitation (0.1-0.3 weoight % ZrC or HfC) is recommended for attaining the maximal short-term strength at 20-1500 deg C and long-term strength up to 1100 deg C

1982-01-01

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)

1991-01-01

7

Structure effect on niobium alloy heat resistance  

International Nuclear Information System (INIS)

Stusied are the possibilities to increase alloy heat resistance due to obtaining structure with optimum grain size. The effect of the grain size on physical and mechanical properties and on heat resistance is studied. The physical nature of this effect is understood. It is established that heat resistance dependence on grain size is nonmonotonous, i.e. the rate of secondary creep of the alloy decreases at first, reaches minimum, and then decreases. It is shown that dependences of X-ray line width, electric resistivity and hardness on grain size are of the same character, that evidences the changes occurring in the structure of the grain itself. Determined are the values of effective energy of recrystallization process activation which agree with views of the controlling role of diffusion processes of different types. The complex of investigations carried out permitted to establish the optimum grain size (100-120 ?m) for alloy providing its maximum level of heat resistance

1980-01-01

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)

1991-01-01

9

Corrosion properties of heat resistant alloys sheets in helium environment  

International Nuclear Information System (INIS)

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

1984-01-01

10

Diffusion welding of molybdenum to hastelloy alloy X  

International Nuclear Information System (INIS)

Diffusion welding between pure molybdenum and heat-resisting alloy Hastelloy X has been performed in vacuum at the temperature range of 7500C-12000C. Two steps welding technique including a short time annealing at high temperature (1 minute at 12000C) increases the real metal-contact between molybdenum and Hastelloy alloy X, and takes the improvements in joint strength. Furthermore, this technique is useful not to enlarge the deformation at weld joint. Application of Ni insert-metal suppresses the formation of brittle intermetallic compound, P phase, and increases the joint strength. However, the formation of binary compound, delta-MoNi, was observed at bonding interface. Fracture of the weld joints by the tensile strength tests at room temperature has occured always through the intermetallic compounds and also along the grain boundaries of molybdenum base metal. After the welding procedure, the voids and MoO2 were found out at the grain boundaries of molybdenum using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. (auth.)

1977-01-01

11

Diffusion welding of molybdenum to hastelloy alloy X  

International Nuclear Information System (INIS)

Diffusion welding between pure molybdenum and heat-resisting alloy hastelloy X has been performed in vacuum at the temperature range of 7500C -- 12000C. Tensile strength of the weld joint at room temperature is discussed on the effects of methods in welding technique and a use of Ni insert-metal. The use of two steps welding technique and a Ni insert-metal is appreciable to improve the tensile strength of weld joint, but the fracture had occured always near weld bond. Metallographical investigations using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction analysis and electron probe X-ray microanalysis have been performed in order to clarify the effects of two steps welding technique and a use of Ni insert-metal on the microstructure near the bonding interface. Results obtained are summarized as follows; (1) Two steps welding technique including a short time annealing at high temperature (1 minute at 12000C) increases the real metal-contact between molybdenum and hastelloy X, and takes the improvement of the joint strength. Furthermore, this technique is useful not to enlarge the deformation by welding procedure. (2) Application of the Ni insert-metal suppresses the formation of the brittle intermetallic compound, P phase, and increases the tensile strength. However the formation of binary compound, delta-MoNi, was observed at the bonding interface. (3) Fracture of the weld joints by the tensile strength tests has occurred always through the intermetallic compounds and also along the grain boundaries of molybdenum base metal. (4) After the welding procedure, the voids and MoO2 were found out at the grain boundaries of molybdenum using SEM and TEM techniques. (auth.)

1977-01-01

12

Determination of allowable stress for a Hastelloy alloy X  

International Nuclear Information System (INIS)

This report presents the initial test results concerning the tensile and creep properties of an Hastelloy alloy X (NC 22 Fe D) solution annealed, and solution annealed then aged. The restrictive test for calculating the structure-size is the stress to cause 1% total elongation for the solution-annealed alloy. The thermal-aging treatments affect the properties of Hastelloy X. The results can be explained by the precipitation of intermetallic molybdenum and tungsten rich phases

1980-06-19

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 10"2"2 m"-"2 (E 0.16 pJ, 1 Mev). Helium coolant : Average temperature 855 "0C, Pressure 2.94 MPa, Total impurity concentration 400 kBq/m"3. 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)

1985-01-01

14

Compatibility of heat resistant alloys with boron carbide, (2)  

International Nuclear Information System (INIS)

In the present design of the control rod for the experimental Very High Temperature Gas-cooled Reactor, sintered pellets of boron carbide mixed with graphite are used as a neutron absorber, which are clad with the sheath material of Hastelloy XR. The sintered pellet contains 30 wt% of natural boron. Chemical reaction occurs between the neutron absorber and the sheath material when they contact mutually at elevated temperature. The term called compatibility is defined as the ability of those materials to be used together without undesirable reaction, in this report. The experimental results on the compatibility of both materials are presented and are discussed on three subjects as (1) the comparison between Hastelloy X and Hastelloy XR, (2) the long term exposure, (3) the effect of the reaction barrier. No difference was observed between Hastelloy X and Hastelloy XR within the conditions of the experiment at 8500C, 9500C and 10500C for each 100 h concerning the first subject. On the second, the penetration depth of 74 um and 156 um were observed on Hastelloy X reacted with sintered pellets (boron carbide and graphite) at 7500C for 3000 h and 8500C for 2000 h, respectively. On the third subject, Hastelloy X surfaces were coated with zirconia or alumina powder by plasma spraying process and by calorizing process in order to prevent the above mentioned reaction. These specimens were tested under two conditions: the one was a simple heat test of 10000C - 100 h and the other was five thermal cycles of 10000C - 20 h. The test results showed that no reaction occurred in the both alloys themselves and some of the coated layers were stripped or cracked. (author)

1982-01-01

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)

1980-01-01

16

Carbonization and carburization of heat resistant alloys in high pressure helium environment  

International Nuclear Information System (INIS)

Interaction of heat resistant structural alloys with impurities in the coolant of High Temperature Gas Cooled Reactor (HTGR) has been experimentally studied in an autoclave with a high pressure He environment. In order to simulate the environment to that of HTGR, oxidation and carburization potentials in the He gas supplied to the autoclave were adjusted to the actual reactor level. This paper describes the carbonization and carburization of heat resistant structural alloys which are selected from various interesting phenomena observed in this experiment. In the higher temperature range of 800 -- 1,0000C, carbides such as Cr23C6, Cr7C3 and Mo2C were detected on the alloy surfaces by X-ray diffraction technique, and were identified as constituents of white surface layers and particles observed by microscopy. On the other hand, in the lower temperature range of 600 -- 8000C, most alloys such as SUS 304 and Hastelloy X were carburized. This carburization is heavier at 6000C than at 8000C. Interference among oxidation, carbonization and carburization is also discussed. (auth.)

1978-01-01

17

Molten salt corrosion of heat resisting alloys  

Energy Technology Data Exchange (ETDEWEB)

This paper is devoted to the study of the corrosion behavior of eight high chromium alloys exposed to three different oil ash deposits with V/(Na+S) atomic ratios 0.58, 2.05 and 13.43, respectively. The alloys were exposed to ash deposits at 750 and 900 C; in this temperature range some deposit constituents have reached their melting point developing a molten salt corrosion process. The group of alloys tested included four Fe-Cr-Ni steels UNS specifications S304000, S31000, N08810 and N08330; two Fe-Cr alloys, UNS S44600 and alloy MA 956; and two Ni-base alloys, UNS N06333 and UNS N06601. The deposits and the exposed surfaces were characterized by chemical analysis, XRD, DTA, SEM and x-ray microanalysis. The oil-ash corrosion resistance of alloys is discussed in terms of the characteristics of corrosion product scales, which are determined by interaction between the alloy and the corrosive environment. All the alloys containing nickel exhibited sulfidation when were exposed at 750 C, but at 900 C only those without aluminum presented sulfidation or sulfidation and oxidation, while the alloys containing aluminum only exhibited internal oxidation. In spite of good resistance to corrosion by oil-ash deposits, 446-type alloy might not be suitable for temperatures higher than 750 C because of embrittlement caused by excessive sigma-phase precipitation. Alloy MA956 showed highest corrosion resistance at 900 C to oil-ash deposits with high vanadium content.

Wong-Moreno, A.; Salgado, R.I.M. [Inst. de Investigaciones Electricas, Morelos (Mexico); Martinez, L. [Programa de Corrosion del Golfo de Mexico, Cuernavaca (Mexico)

1995-09-01

18

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 S_o, S_m and S_t were computed using similar procedure employed for the previous data on Hastelloy XR with lower boron content. The significant increase in the S_o and S_t for Hastelloy XR-II over Hastelloy XR is recognized due to the improvement of both creep strength and creep-rupture ductility. (J.P.N.)

1993-01-01

19

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)

1979-09-01

20

Heat resistance of multicomponent coatings on the niobium alloys  

International Nuclear Information System (INIS)

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

1980-01-01

 
 
 
 
21

Corrosion behavior of heat resistant alloys for gas seal elements of VHTR in helium environment  

International Nuclear Information System (INIS)

The corrosion behavior of the heat resistant alloys for the gas seal elements used for the fixed reflectors to improve the thermal flow characteristics in the core of the high tempeerature gas-cooled experimental reactor was examined in helium. As the results, the following facts were clarified. In Hastelloy X and Incoloy 800, carburization was observed below 900 deg C. Especially in the state of contact with graphite, carburization was promoted more than the case of non-contact. In Incoloy MA 956, decarbonization and carburization were suppressed below 800 deg C in helium, but in the state of contact with graphite, carburization was observed. When Al2O3 was coated on the surfaces of test pieces by chemical vacuum evaporation, oxidation, decarbonization and carburization were suppressed. The Al2O3 film coated on Hastelloy X by chemical vacuum evaporation showed sufficient reliability against thermal cycles and repeated bending. In the high temperature gas-cooled experimental reactor, the crossflow of helium through the gaps between graphite blocks lowers the thermal flow characteristics, therefore, the use of the gas seal elements made of 0.4 mm metallic sheets is considered. It is required to examine the reaction with the impurities in helium and the reaction in contact with graphite. (Kako, I.)

1984-01-01

22

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)

1986-01-01

23

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)

1986-01-01

24

Evaluation of creep and relaxation data for hastelloy alloy x sheet  

International Nuclear Information System (INIS)

Hastelloy alloy X has been a successful high-temperature structural material for more than two decades. Recently, Hastelloy alloy X sheet has been selected as a prime structural material for the proposed Brayton Isotope Power System (BIPS). The material also sees extensive application in the High-Temperature Gas-Cooled Reactor (HTGR). Design of these systems requires a detailed consideration of the high-temperature creep properties of this material. Therefore, available creep, creep-rupture, and relaxation data for Hastelloy alloy X were collected and analyzed to yield mathematical representations of the behavior for design use

1979-01-01

25

Evaluation of creep and relaxation data for hastelloy alloy x sheet  

Energy Technology Data Exchange (ETDEWEB)

Hastelloy alloy X has been a successful high-temperature structural material for more than two decades. Recently, Hastelloy alloy X sheet has been selected as a prime structural material for the proposed Brayton Isotope Power System (BIPS). The material also sees extensive application in the High-Temperature Gas-Cooled Reactor (HTGR). Design of these systems requires a detailed consideration of the high-temperature creep properties of this material. Therefore, available creep, creep-rupture, and relaxation data for Hastelloy alloy X were collected and analyzed to yield mathematical representations of the behavior for design use.

Booker, M.K.

1979-02-01

26

Effect of decarburizing helium environment on creep behavior of Ni-base heat-resistant alloys for high-temperature gas-cooled reactors  

Energy Technology Data Exchange (ETDEWEB)

Creep tests of Ni-base heat resistant alloys (Hastelloy XR and XR-II) were conducted at 950deg C in four kinds of helium environments with different impurity compositions in order to examine the effect of decarburizing environment. Both alloys were decarburized in a 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. Whether the decarburization of the Hastelloy XR and XR-II might occur or not in the primary helium coolant of high temperature gas-cooled reactor (HTGR) could be predicted by using a corrosion map of a stability diagram for chromium. Controlling impurities to maintain higher partial pressure of exygen and carbon activity in primary helium coolant of HTGR is proposed in order to prevent degradation of creep properties of the materials caused by decarburization.

Kurata, Yuji; Ogawa, Yutaka; Nakajima, Hajime

1988-02-01

27

Effects of Cyclic Aging on Mechanical Properties and Microstructures of Hastelloy Alloy X.  

Science.gov (United States)

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 mech...

M. Kikuchi K. Watanabe T. Kondo

1982-01-01

28

Classification of heat resisting nickel alloys according to weldability in electron beam welding  

International Nuclear Information System (INIS)

Weldability during electron beam welding of 30 grades of heat-resisting nickel alloys is investigated. Classification of weldability of such alloys is suggested. Technological measures increasing the weldability level are described

1980-12-01

29

Friction and wear characteristics of nickel-based heat-resisting alloy and ceramic coating materials in high temperature helium gas  

International Nuclear Information System (INIS)

Relative sliding or bumping of structural elements during the operation of a very high-temperature gas-cooled reactor (VHTR), which has been developed by the Japan Atomic Energy Research Institute, are to be caused supposedly by thermal expansion, flow-induced vibration, seismic forces etc. Appropriate measures, therefore, must be taken in order to prevent abnormal wear, seizing or failure of these structural elements. The friction and wear characteristics of Ni-based heat-resisting alloy (Hastelloy X-R), which is now thought to be one of the promising candidate materials for VHTR structures, and several ceramic materials by which the surfaces of Hastelloy X-R are to be coated, were studied in 1,000"0C and 0.2--4.1 MPa He gas environment. The followings are the conclusions derived from the present experiment: (1) The friction coefficient of Hastelloy X-R against itself decreased with increasing O_2 gas partial pressure within 3 kPa in the He gas environment. (2) The mutual transfer of material elements occurred when the material combination was Hastelloy X-R against ZrO_2 coating. (3) The friction and wear characteristics of ZrO_2 and TiC coatings against themselves were stable. (author)

1985-01-01

30

REM effect on mechanical properties and structure of heat resistant alpha-titanium alloy  

International Nuclear Information System (INIS)

Micro alloying with rare-earth metals (La, Dy, Y, Ce) of heat resisting titanium alloy VT18U has been studied for its effect on beta-phase amount, mechanical properties at 20 grad C, long-term rupture strength and creep at 600 grad C. The best results have been obtained for 0.005% La or 0.1%Ce additions. In the latter case along with high heat resistance satisfactory values of plasticity and impact strength are preserved

1994-05-01

31

Chemical Compatibility of Barium-Calcium-Aluminosilicate Based Sealing Glasses with Heat Resistant Alloys  

Energy Technology Data Exchange (ETDEWEB)

Over the past several years, advances in the design and fabrication of planar SOFCs have led to a steady reduction in the temperatures necessary for their operation. Consequently, it appears more realistic now to use low cost heat resistant alloys for interconnect sub-components in the SOFC stack. Considering these materials requirements, heat resistant alloys, which overall demonstrate oxidation resistance at elevated temperatures, could be potential candidates. Overall, the heat resistant alloys of interest may include superalloys and the stainless steels. Depending whether a chromia or alumina scale forms on the alloy surface for protection, these heat resistant alloys can be also classified into chromia or alumina formers, repetitively. To help screening alloys and understanding the interface of sealing glass, a couple of alloy compositions have been carefully chosen as a reprehensive of different groups of alloys for the study on their chemical compatibility with a barium-aluminosilicate base glass. These alloys selected are AL 29-4, Nicrofer 6025, and Fecralloy, representing chromia forming stainless steels, superalloys and alumina formers, respectively. Results of chemical and microstructural analyses on sealing glass interfaces with different alloys will be presented, and accordingly, the applicability of alloys in terms of sealing glass chemical compatibility will be discussed. Possible means of modification on alloys for an improved applicability will be elaborated as well.

Yang, Z Gary; Weil, K. Scott; Meinhardt, Kerry D.; Stevenson, Jeffry W.; Paxton, Dean M.; Xia, Gordon; Kim, Dong-Sang

2003-09-15

32

Improvement of Ti heat resistance by electrospark alloying  

International Nuclear Information System (INIS)

Titanium heat resistance can be increased by electrospark doping. Aluminium appears to be a cheap and effective material for protective electrospark coating. It is applied using a multielectrode rotating instrument. Long-term annealing of titanium with such coating in the air at 600 deg C improves its subsequent operation properties. The maximum titanium operation temperature is 800 deg C

1993-01-01

33

Alloying effect on the heat resistance of Nb-Fi-Al alloy systems  

International Nuclear Information System (INIS)

By methods of continuous weighting and X-ray phase analysis studied is the effect of alloying elements additisons on the weight gain of VN-7 type alloys in calm air at temperatures of 1100-1300 deg C as well as the phase composition of scale. Additions: 1-5% Cr, 2-10% Hf, 5-15% Ta, 2% V and 2% Zr, improves the heat resistance of alloys whereas additions: 5-15% Mo, 5-10% V or 5-10% Zr, deteriorate it. Scale on the VN-7 alloy and its modifications with different additions includes 2 phases: TiO_2 (rutile, tetragonal lattice) and TiO_2xNb_2O_5 (monoclinic lattice) where alloying elements dissolve

1981-01-01

34

Method for obtaining heat-resistant coatings on niobium alloy products  

International Nuclear Information System (INIS)

A new method of heat-resistant coating of niobium alloy products is suggested. The method consists of the treatment at 900-1100 deg C in liquid-metal melt, containing saturating elements. To increase the heat resistance of coatings, as well as to simplify the process of coating, the treatment is conducted in sodium base melt containing Al, Si, Ti, Cr (5-10 %) as saturating elements

1980-01-01

35

Creep and Tensile Properties of Alloy 800H-Hastelloy X Weldments.  

Science.gov (United States)

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 We...

H. E. McCoy J. F. King

1983-01-01

36

Internal stress during high-temperature creep of special grade Hastelloy X alloys  

International Nuclear Information System (INIS)

Creep tests and the measurement of internal stress during creep were performed at 9000C for Hastelloy XR and XR-II, i.e. versions of Hastelloy X modified for nuclear applications. Creep rupture time and steady-state creep rate were influenced by the boron content, grain size and heat-treatment temperature of the alloys. It is shown that the difference in the steady-state creep rate is caused by the internal stress dependent on the boron content, grain size and solution-treatment temperature. (orig.)

1988-01-01

37

Internal stress during high-temperature creep of special grade hastelloy X alloys  

Science.gov (United States)

Creep tests and the measurement of internal stress during creep were performed at 900°C for Hastelloy XR and XR-II, i.e. versions of Hastelloy X modified for nuclear applications. Creep rupture time and steady-state creep rate were influenced by the boron content, grain size and heat-treatment temperature of the alloys. It is shown that the difference in the steady-state creep rate is caused by the internal stress dependent on the boron content, grain size and solution-treatment temperature.

Kurata, Yuji; Ogawa, Yutaka

1988-09-01

38

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

Directory of Open Access Journals (Sweden)

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

Graneix Jérémie

2013-11-01

39

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

Energy Technology Data Exchange (ETDEWEB)

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.

McCoy, H. E.; King, J. F.

1983-08-01

40

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

1983-01-01

 
 
 
 
41

Heat resisting steel properties at complex nickel and aluminium alloying  

International Nuclear Information System (INIS)

Efficiency of effect of combined nickel and aluminium alloying up to 8% for each on the properties of manganese steel of austenitic class [6] are investigated. It is ascertained that complex aluminium and nickel alloying by 6% of each one leads to steel precipitation hardening with the maximum strength increase by 20% at 750 deg C ageing temperature

1989-01-01

42

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

1997-01-01

43

Heat resistance and high-temperature strength of niobium alloys with coatings  

International Nuclear Information System (INIS)

Heat resistance and high-temperature strength of niobium NTsU and 5BMTs alloys with diffusion coatings are investigated. Three-layer Al+Cr+Si and Al+Cr+Si+Ti coatings with 40 and 35 ?m thickness respectively are produced after complex diffusion saturation of niobium alloys in sodium melt with Al, Cr, Si, Ti elements. It is shown that multicomponent Al+Cr+Si and Al+Cr+Si+Ti coatings on niobium alloys provide for heat resistance of the latter as well as for high-temperature strength and plasticity under their operation in argon medium, increase sufficiently the time up to the main material destruction in the air at high temperature and applied voltage of no more than 150 MPa

1989-01-01

44

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

International Nuclear Information System (INIS)

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

1996-01-01

45

Evaporation behavior of Hastelloy-X alloys in simulated very high temperature reactor environments  

International Nuclear Information System (INIS)

A sequential analysis was made on the material degradations during exposure of nickel-base corrosionresistant austenitic alloys to simulated very high temperature reactor environments. The materials tested were two modified versions of Hastelloy-X in terms of both increased manganese content for improved compatibility and decreased manganese content for possible adverse effects. Quantitative analysis of the specimens after exposure for 1000 h at several temperature steps from 850 to 10500C have revealed the temperature-dependent aspects of the processes including the depletion of chromium and manganese due to oxidation, evaporation, and carbon transfer into and/or from the materials. The material with enriched manganese, developed and specified as Hastelloy-XR, showed enhanced resistance to loss of chromium in terms of both oxidation and evaporation

1984-01-01

46

Development of thermal insulation layers for heat-resisting alloys  

International Nuclear Information System (INIS)

The dissertation examines means and possibilities of treating the surface of commercial alloys used for turbines in order to enhance their corrosion resistance of high temperatures (hot-gas corrosion), and to achieve a thermal insulation against flowing hot gas. The thermal insulation layer is to consist of high-melting oxides. The adhesiveness of oxides on metals is known to be insufficient, due to thermomechanical stresses and to low adhesive forces between metals and ceramics. Hence suitable bonding agents have to be found that comply with the required hot-gas corrosion resistance. The studies showed the following layer composition to be suitable: (1) INCONEL 617, (2) with helical wires tip brazed with Ni4Cr2Ti0.5Si2.5 (wire diameter 0.3 mm, spiral diameter 3 mm), (3) soda-lime glass with addition of ZrO2/Y2O3, and (4) topmost thermal insulation layer made of 10 vol-% aluminium silicate fibre, 70 vol.-% ZrO2/7Y2O3, 5 vol.-% GeO2 and 15 vol.-% of a gel (consisting of 61 mol-% Si (OH)4/20 mol-% Y(OH)3 and 19 mol-% Zr (OH)4). This layer composition allows to deposit thermal insulation layers of more than two millimetres in thickness onto nickel-base alloys. (orig.)

1990-01-01

47

Experiment planning during investigation of heat resistance of Fe-Cr-Ni-Mn-Si-Al-REM system alloys  

International Nuclear Information System (INIS)

Heat resistance of alloys of Fe-Cr-Ni-Mn-Si-Al-REM sytem is studied at temperatures of 800-900 deg C in the air medium. It is shown that in studied ranges the changes of alloys compositions, their heat resistance both at 900 and 800 deg C depends greatly on the content of silicon in alloys. In both cases the increase of silicon content up to 2% decreases the mass change sufficiently. The ratio between the quantities of chromium and silicon, and manganese and rare earth metals as well, has a notable effect on heat resistance at both temperatures of test

1981-01-01

48

Processing parameters effect on dendritic segregation in heat resistant nickel alloy  

International Nuclear Information System (INIS)

Study on impact of the scheme for melting the ingots-electrodes diameter 85 mm of heat-resistant nickel alloy is carried out through the methods of track, activation autoradiography, metallographic and microroentgen-spectra analysis with application of vacuum arc, electroslag, electrobeam, vacuum arc two-electrode remelting, as well as ingots thermal and heat isostatic treatment for dendrite liquation of boron and carbon in the heat resistant nickel alloy Ni-5Al-2Ti-9Cr-16Co-6W-4Mo-3Nb-Hf-C-B. Regularities of the melting scheme impact on dendrite structure dispersity and the level of dendrite liquation development are established. The mechanism of the melting scheme impact on liquation is proposed

1997-01-01

49

Structure of crater of sputtered electrode of heat resisting nickel alloy under granulation process  

International Nuclear Information System (INIS)

Analysis of the structure formed in the crater of centrifigally sputtered electrode of Ni-Al-Ti-Cr-Co-W-Mo-Nb-Hf-B system granulated heat-resistant nickel alloy is carried out. Essential difference in behaviour of boron and carbon in crater near-the-surface layer is determined. This difference results from the depth of homogeneous distribution of boron (up to 1 mm) in contrast to that of carbon (up to 0.1mm). Up to 10 mm depth crack formation is detected. That crack formation results from the effect of thermal gradient at electrode sputtering followed by formation of submelting pores due to boron intensive migration to crack and along it on the surface of crater. Compositions of boride and carbide phases are determined, mechanisms of crater formation of electrode crater of heat-resistant granulated nickel alloy are suggested

1993-02-01

50

Effect of hot deformation and heat treatment on structure formation in heat resistant on structure formation in heat resistant complex nickel base alloy  

International Nuclear Information System (INIS)

The methods of autoradiography, metallography and X-ray spectral microanalysis were used to study the effect of hot upsetting of cylindrical samples of heat resistant cast Ni-5Al-2Ti-9Gr-15Co-10W-Mo-2Nb-Fe-C-B alloy at 1100, 1150, 1175 and 1200 deg C temperatures, 30, 50 and 70% deformation degrees and 10-3 and 10-1s-1 strain rates which were chosen taking into account the typical conditions for hot deformation of heat resistant nickel based alloys. The regularities were found and the mechanisms of structure formation and boron and carbon behaviour under deformation and subsequent heat treatment were offered

1993-03-01

51

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

1978-01-01

52

Influence of high temperature treatment of melt on single crystal structure of heat resisting alloys  

International Nuclear Information System (INIS)

The structure and strength properties of monocrystals with the growth axis of two heat resisting nickel-base alloys after various modes of high-temperature treatment of the melt have been investigated. By the methods of electron microscopy, X-ray diffraction analysis and metallography, the influence of temperature of the melt on structural perfection of the monocrystals, parameters of cellular-dendritic structure, morphology and dispersion of strengthening ?'-phase, degree of coherence in ?/?' phase interface and their interrelation with long-term rupture strength of the alloys studied, has been analyzed

1991-01-01

53

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 1000"0C. 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 1000"0C 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)

54

Design and development of super-heating resisting Nb-based and Mo-based alloys  

International Nuclear Information System (INIS)

Nb-based and Mo-based alloys which are refractory metals are ones of the promising materials for advanced nuclear power systems of high temperature applications. Alloy design of Nb-based and Mo-based super-heat resisting alloys was performed in order to develop these alloys possessing high temperature strength and excellent corrosion resistance under alkali liquid metal environment. A d-electrons alloy theory using a molecular orbital calculation was applied to present alloy design. The micro-Vickers hardness at room and elevated temperature which was mechanical property, workability and melting point which was index of creep properties, were obtained by various experiments. And, they were arranged and estimated using the theoretical alloy parameters. The corrosion tests were carried out with binary Nb-based and Mo-based alloys in liquid Li at 1473K. The alloying element which was effective in improving the corrosion resistance was investigated from the experimental results. Accordingly, the Nb-based and Mo-based alloys systems having the higher strength at elevated temperature and excellent corrosion resistance were found out from these results. (author)

1996-03-01

55

Fundamental principles of structure formation in manufacturing discs from ultrahigh heat resistant alloys  

International Nuclear Information System (INIS)

The problems, related to machining by pressure of heat resistant nickel base alloys, used for manufacturing discs of gas-turbine engines, are considered. It is noted, that the following factors: the temperatures of stamping and subsequent thermal treatment are of special importance for achieving the necessary complex of properties, whereby the temperature of the ?'-phase complete solution and carbide form atom reaction, as well as the level of residual deformation, should be accounted for. It is shown, that the optimal combination of mechanical properties is obtained after quenching at temperatures close to the temperature of the ?'-phase complete solution. The increase in the heat resistance up to 700 deg C is achieved due to preservation of the fine-grain structure after deformation in the single-phase area and quenching in the double-phase area

2000-01-01

56

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

1986-06-01

57

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

2000-01-01

58

Various problems in high temperature strength of heat resistant super-alloys for high temperature gas-cooled reactors  

International Nuclear Information System (INIS)

In July, 1973, the research and development on the direct iron-making technology utilizing high temperature reducing gas were started as a big national project. As the research items, heat resistant super-alloys, high temperature heat exchangers, heat-insulating materials as well as high temperature gas-cooled reactors were enumerated. The aim of the research and development of heat resistant super-alloys is to develop the alloy which has the creep rupture strength for 50,000 hours of higher than 1 kg/mm2 in 1,000 deg C helium atmosphere. This alloy must be worked into tubes of 25 mm outside diameter, 5 mm thickness and at least 7 m length, and the secondary working and welding required for the manufacture of heat exchangers must be possible. The high temperature strength and workability of heat resistant alloys are incompatible properties. The creep rupture strength of heat resistant alloys deteriorates in helium atmosphere. In this paper, the test results on the high temperature strength of ten candiate alloys, which passed the manufacturing test and working test, are reported. The creep rupture strength of H-alloy and I-alloy in 1,000 deg C helium seemed to satisfy the condition. (Kako, I.)

1981-05-30

59

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

1986-05-01

60

Compatibility of heat resistant metals with graphite in helium environment  

International Nuclear Information System (INIS)

This paper describes compatibility of heat resistant metals with graphite in pure helium environment. Experiments were carried out for tantalum, niobium and molybdenum in the temperature range of 1000 - 1400"0C, and for some Ni-Cr-Fe alloys, such as Hastelloy X, Hastelloy XR, Incoloy 800, Inconel 600 and Inconel 617 in the range of 900 - 1100"0C for 90 hours. Molybdenum sticked to graphite at temperatures above 1200"0C. Tantalum and niobium absorbed oxygen from the atmosphere, and carbon from graphite, but did not stick to graphite. Among Ni-Cr-Fe alloys, those containing molybdenum, such as Hastelloy X, Hastelloy XR and Inconel 617, sticked to graphite at 1100"0C Diffusion of metals into graphite was observed. At temperatures below 1000"0C. carburization was scarcely observed with the exception of Inconel 600. To improve the compatibility, alumina was coated on some metal specimens by chemical vapor deposition method. This coating prevented molybdenum and Hastelloy X from sticking to graphite at 1300"0C and at 1100"0C, respectively. (author)

1981-01-01

 
 
 
 
61

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 1000"0C when carbon pickup is high. Dilation was normally observed only when the carbon increase was >1000 ?g/cm"2 and ceased when the diffusing carbon reached the center of the specimen

1981-05-05

62

Progress with heat resistant materials for waste incineration -- Alloy 45TM  

Energy Technology Data Exchange (ETDEWEB)

Heat resistant materials are used in a wide variety of modem industries such as metallurgical, chemical, petrochemical, heat treatment, heat recovery and waste incinerators and many others. The huge quantities of both municipal and industrial waste generated in the Western world has made ``controlled high temperature incineration`` a necessary technology for managing this problem. The evolution of this technology has not been without its cost. High temperature corrosion problems have led to many failures and unscheduled shutdowns. Proper materials of construction are vitally important for reliable, safe and cost effective operation of these systems. This paper describes the development of a new nickel based alloy, which combines the beneficial effects of high chromium and high silicon in combating these various corrosive environments encountered in incineration.

Agarwal, D.C. [VDM Technologies, Houston, TX (United States); Brill, U.; Kloewer, J. [Krupp-VDM GmbH, Werdohl (Germany)

1995-12-01

63

Low-cyclic fatigue of heat resisting alloys under nonisothermal loading  

International Nuclear Information System (INIS)

On the example of two heat resisting EhP693VD and EhP220 alloys contrasting by short-term and long-term strength and ductility characteristics considered both specific features of the process of cyclic elastoplastic deformation under thermal-fatigue loading and conditions of maximum permissible damages formation are discussed. Tests have been performed at the temperatures from 20 to 1000 deg C. It is shown that the non-stationary character of the process of elastoplastic deformation with accumulation of unilateral strains and important quasistatic damages is characteristic of the thermal fatigue regime in the high temperature field. The deformation-kinetic dependence satisfactorily describing the limiting state on fracture under thermal-fatigue loading of steel samples is presented

1982-06-01

64

Study of aluminium and titanium total quantity ratio effect on the technological plasticity of high alloyed nickel heat resisting alloys  

International Nuclear Information System (INIS)

To understand the effect of the total aluminium and titanium content on the standard plastisity of heat-resistant alloys added with refractory elements (tungsten, molybdenum, cobalt, niobium) ingots 160 mm in diameter have been studied, obtained by the VAM method with the content of ? Ti+Al=0-8%. An aluminium-and titanium-free alloy has a satisfactory plastisity in the test temperature interval 950-1200deg C. At an increased combined content of these metals the standard plastisity falls within the entire test temperature interval. The temperature interval of the maximum standard plastisity becomes tangibly narrower as ? Al+Ti increases. The change of the microhardness of heatresistant alloys added with tungsten, molybdenum, cobalt, niobium correlates with plastisity variation depending on the total content of aluminium and titanium

1976-01-01

65

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 1,000"0C 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 900"0C, 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 1,000"0C, however, considerable difference was observed owing mainly to the difference in decarburization. (author)

1980-01-01

66

Mechanical properties of heat-resistant alloys exposed to air and HTGR helium at high temperatures  

International Nuclear Information System (INIS)

The effect of a corroded surface layer on the tensile properties and the high-temperature low-cycle fatigue life was studied on Hastelloy-X and on Incoloy alloys 800 and 800H by comparing the properties between specimens exposed to air and high-temperature gas-cooled reactor helium at 10000C prior to testing and specimens aged under the same temperature/time conditions as those of exposed specimens. The ratio of the corroded surface layer to the total cross-sectional area was controlled at 10000C by environment, exposure time, and shape/size combinations of specimens. Tensile strength could be quantitatively expressed in terms of the intergranular oxidation, irrespective of the variation of materials and corrosive conditions. By comparing the low-cycle fatigue lives at 10000C between exposed and aged materials, it was clarified that lifetime was remarkably reduced by the formation of a corroded surface layer. However, fatigue life of aged material was less than that of solution-treated materials. These two opposing effects of corrosion and aging brought about a small difference in fatigue life between solution-treated and exposed materials

1984-01-01

67

Hardening of the heat-resisting chromium-nickel KhN56VMKYu alloy with dispersion oxide phase  

International Nuclear Information System (INIS)

The structure and properties commercial heat-resisting KhN56VMKYu alloy, hardened by the disperse particles of zirconium dioxide (ZrO2) introduced during vacuum-arch remelting are investigated. It is established that microstructure of all the ingots is characterized by relatively fine, gradually distributed over all the matrix volume inclusions. Analysis of the results obtained during short-time mechanical tests has shown that at all the temperatures strength characteristics of the KhN56VMKYu alloy with the introduced oxide phase are practically on the same level with similar parameters of commercial alloy. Durability of precipitation-hardened alloy obtained on the base of heat-resistant KhN56VMKYu matrix as compared with conventional metal of the same brand is mich higher. 100-hour strength at 900-1100 deg C increases by approximately 20 MPa when introducing ZrO2 particles into the KhN56VMKYu alloy. It is shown that ZrO2 oxide phase introduction into the alloy improves its heat resistance. At 1100 deg C oxidation rate of the KhN56VMKYu alloy hardened with zirconium dioxide, decreased from 0.4 to 0.3 g/m2xhr which is conditioned by the change of the phase composition of scale

1981-01-01

68

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

Energy Technology Data Exchange (ETDEWEB)

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.

Howell, E.I.; Teaney, P.E.

1993-09-29

69

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

1993-01-01

70

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

Energy Technology Data Exchange (ETDEWEB)

Research highlights: {yields} The segregation concentration is much higher in dimples that at grain boundaries. {yields} The prominent segregation of tin and tellurium is observed during rupture test. {yields} 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 = t{sub 0}.{sigma}{sup -n}.exp(Q/RT) where t{sub 0} 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 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.

Heo, N.H., E-mail: nhheo@kepri.re.kr [KEPCO Research Institute, 65 Munji-Ro, Yusung-Gu, Daejeon 305-380 (Korea, Republic of); Chang, J.C.; Yoo, K.B. [KEPCO Research Institute, 65 Munji-Ro, Yusung-Gu, Daejeon 305-380 (Korea, Republic of); Lee, J.K. [PILETA Ltd Co, 65 Munji-Ro, Yusung-Gu, Daejeon 305-380 (Korea, Republic of); Kim, J. [Department of Metals Engineering, Hanyang University, Ansan 425-791 (Korea, Republic of)

2011-03-15

71

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 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.

2011-03-15

72

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 -- 1000_0C. 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 900_0C, the ductility loss of the cyclic case is higher than that of the isothermal, while the relation is reversed at 1000_0C. (author)

1982-01-01

73

Weld metal hot-cracking of Hastelloy alloys C-22 and C-276: a study by analytical electron microscopy  

International Nuclear Information System (INIS)

Weld metal hot-cracking in multi-component alloy systems is often the result of the formation of small volume fractions of nonequilibrium constituents along solidification grain boundaries. These constituents arise as a result of the segregation phenomenon accompanying weld solidification and often serve to extend the solidification temperature range well below the equilibrium solidus. Purpose of this study was to identify and characterize (crystal structure and composition) by analytical electron microscopy (AEM) the phases associated with weld metal hot-cracking in Hastelloy alloys C-22 and C-276

1985-08-05

74

The effects of controlled impurity helium on the mechanical behavior of Hastelloy Alloy X  

International Nuclear Information System (INIS)

The influence of a simulated advanced reactor helium environment, containing 50 Pa H2/5 Pa CH4/ 5 Pa CO/ about 0.1 Pa H2O, on the mechanical properties of two heats of Hastelloy alloy X is discussed. Simultaneous exposures in air and controlled impurity helium at temperatures in the range of 650 to 10000C for times of 3000 h or more were performed. A combination of tensile testing, Charpy V-notch impact toughness testing, and creep testing was used to study the effects of reactor helium/metal interactions on the mechanical behavior of this alloy. Carburization was identified as the primary corrosion phenomenon. Increasing exposure time and temperature were observed to increase the depth of carburization. The increase in carbon concentration in the carburized zone suppressed the additional formation of M C, which is observed in air-aged specimens, and resulted in the precipitation of M23C6 a chromium-rich carbide variant. The precipitation of M23C6 in the carburized zone occurred primarily along grain and twin boundaries; matrix precipitation, however, was also observed, the degree of which depended on exposure temperature. Strength and impact toughness properties were found to be controlled primarily by thermal aging reactions, with only a small effect related to the carburization. Although tensile and creep ductilities were decreased as a result of carburization, substantial ductility remained. Variation was observed between the two heats, the finer grained heat appearing to be weaker in the high-temperature creep tests and also possibly more susceptible to a loss of creep strength as a result of carburization

1984-01-01

75

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%.

2012-04-16

76

Effect of boron on weldability and high temperature strength of hastelloy XR alloy  

International Nuclear Information System (INIS)

Recently, it is desired to improve the high temperature strength of welds of Hastelloy XR, a structural material for high temperature gas-cooled reactors. In this report, a study is carried out on boron, a trace constituent of Hastelloy XR, in an effort to improve the absolute strength of welds by increasing the strength of the matrix material. The boron content is varried over the range prescribed in the Hastelloy composition specification (100 ppm maximum), and effects of the boron content on the weldability and high temperature strength of Hastelloy are investigated. Specimens are welded by the high voltage electron beam welding technique, and the welded portions are subjected to X-ray transmission testing and microscopic composition observation. The major welding defects produced are found to be porosity and micro-cracking. TIG weldability testing is also conducted. It is shown that the high temperature strength of Hastelloy XR increases while the weldability decreases with increasing boron content. Taking into consideration the balance between the weldability and high temperature strength, it is concluded that the optimum boron content in Hastelloy is 40 ? 70 ppm. (Nogami, K.)

1986-01-01

77

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

1978-01-01

78

Crevice Corrosion of Hastelloy C-276 and Inconel-625 Alloys in Chloride Environments, Determination of The Critical Crevice Solution  

International Nuclear Information System (INIS)

The crevice corrosion of hastelloy C-276 and Inconel-625 alloys is investigated. The effect of temperature on both passive current and the critical pH (at which the passive film breaks down) is studied in detail. potentiodynamic studies have been used to determine the critical crevice solution (CCS) in terms of pH and chloride iron concentration, and passive current. The criteria of both Crolet and Old field and Sutton are used for the determination of the critical pH for crevice corrosion. The results show that the critical pH for crevice corrosion of Inconel-625 alloy as defined by Old field and Sutton seems to be a function of both temperature and chloride ion concentration, whereas the same relationship does not appear to hold between these variables and the critical pH when the Crolet criterion is applied. The critical pH of crevice solution for Inconel-625 may vary between 1.7 and 0.0 depending on environmental condition and criteria applied. However, for the case of hastelloy C-276 alloy the critical pH for crevice corrosion could not be detected when applying both criteria. The results indicate that hastelloy C-276 alloy is more resistant to crevice corrosion than Inconel-625 under the same experimental conditions. The experimental results passive current (Ipass) and de passivation pH (dpH) of this investigation could be utilized as inputs to a mathematical model employed for the prediction of incubation period required to reach the critical crevice solution composition, which leads to permanent breakdown of passive film. 10 figs., 5 tabs

1994-03-01

79

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

Energy Technology Data Exchange (ETDEWEB)

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%.

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

80

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fe-Cr-Ni heat resistant alloys with aluminum and silicon addition, alone and in combination, were melted using an intermediate frequency induction furnace with a non-oxidation method. By the oxidation weight gain method, the oxidation resistances of the test alloys were determined at 1,200 ìC for 500 hours. According to the oxidation weight gains, the oxidation kinetic curves were plotted and the functions were regressed by the least squares method. The results show that the oxidation kineti...

2009-01-01

 
 
 
 
81

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

Science.gov (United States)

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.

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

2014-07-01

82

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

Energy Technology Data Exchange (ETDEWEB)

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

Choi, Hong Seok; Ko, Dae Chul; Kim, Byung Min [Pusan National Univ., Busan (Korea, Republic of)

2007-07-01

83

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

International Nuclear Information System (INIS)

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

2007-06-01

84

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

Directory of Open Access Journals (Sweden)

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.

Ohnuma I.

2012-01-01

85

The diffusion model of pores vacancy dissolution at gaseous isostatic pressing of heat resistant nickel alloy monocrystal  

International Nuclear Information System (INIS)

Diffusion model of vacancy dissolution of pores under the action of all-round compression stresses (gas isostatic pressing) and capillar forces is proposed. The experiments are carried out using a nickel base heat resistant alloy single crystal. At the initial stage of the process the external pressure effect is shown to be predominant. The time of dissolution is in inverse proportion to the stress and depends quadratically on the initial pore size. At the final stage (a pore radius less than 100 nm) the pore disappears rapidly under the action of capillar forces

2006-03-01

86

Influence of the melting technology on the structure and properties of the heat resistant alloy EhI867  

International Nuclear Information System (INIS)

A comparative investigation has been made of the structure and properties of EhI867 heat-resistant alloy in 40 mm diameter rods (stamp designation KhN62MVKYuR), Ni3Al phase hardened, smelted in an open high-frequency induction furnace and remelted by various techniques. Substantial improvement of all characteristics was observed following remelt: reduction of contamination by nitrides and other non-metal impurities, increased technological ductility at hot deformation temperatures, increased crack formation work, improved strength and ductility characteristics at working temperatures around 9000C, enhanced creep strength, etc. (author)

1975-01-01

87

Cracks in die stampings made of heat-resistant nickel alloys and technological methods to prevent them  

International Nuclear Information System (INIS)

Cracks in die stampings made of EhP975ID type nickel superalloys are described. The following technological techniques are recommended to prevent quenching crack formation: regulating heating to quenching temperature, delayed short-time cooling prior to air quenching, decrease in die stamping mass by the preliminary turning prior to quenching, prevention of hitting the die stampings against the elements of the equipment. The described methods don't exclude completely the formation of quenching cracks due to unfavorable structural factors but they significantly decrease a probability of their initiation. These recommendations can also be applied to other heat-resistant nickel alloys

2001-01-01

88

Creep-rupture behavior of 2-1/4 Cr-1 Mo steel, Alloy 800H and Hastelloy Alloy X in a simulated HTGR helium environment  

International Nuclear Information System (INIS)

Creep-rupture testing was conducted on 1 1/4 Cr-1 Mo steel, Alloy 800H and Hastelloy Alloy X in flowing helium containing nominal concentration of following gases: 1500 ?atm H2, 450 ?atm CO, 50 ?atm CH4, 50 ?atm H2O and 5 ?atm CO2. This environment is believed to represent maximum permissible levels of impurities in the primary coolant for the steam-cycle system of a high-temperature gas-cooled reactor (HTGR) when it is operating continuously with a water and/or steam leak at technical specification limits. Two or three heats of material for each alloy were investigated. Tests were conducted at 4820C and 7600C (12000F and 14000F) for Alloy 800H, and at 7600C and 8710C (14000F and 16000F) for Hastelloy Alloy X for times up to 10,000 h. Selected tests were performed on same heat of material in both air and helium environments to make a direct comparison of creep-rupture behaviors between two environments. Metallurgical evaluation was performed on selected post test specimens with respect to gas-metal interactions which included oxidation, carburization and/or decarburization. Correlation between gaseous corrosion and creep-rupture behavior was attempted. Limited tests were also performed to investigate the specimen size effects on creep-rupture behavior in the helium environment

89

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

Energy Technology Data Exchange (ETDEWEB)

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.

Lystrup, A. S.; Rittenhouse, P. L.; DiStefano, J. R.

1977-11-01

90

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)

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.

Lystrup, Aage

1977-01-01

91

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)

1981-01-01

92

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)

1994-01-01

93

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)

1994-01-01

94

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

International Nuclear Information System (INIS)

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

1982-06-02

95

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 E_corr. and E_b. 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

1994-03-01

96

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

International Nuclear Information System (INIS)

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

2013-10-01

97

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-10-15

98

Design of super heat-resisting Nb-based alloys for nuclear applications  

International Nuclear Information System (INIS)

Nb-based alloys are ones of the promising materials for structural applications in advanced nuclear power systems. A systematic estimation for high-temperature tensile strength, high-temperature creep strength, corrosion resistance to liquid sodium and alloy density was performed in order to get useful information for the design of the Nb-based alloys, as was similarily done for Mo-based alloys. The high-temperature micro-hardness and the high-temperature tensile strength were found to be predictable using the same calculation method employed in the Mo-based alloys. The differences in the atomic radius and in the Young's modulus between the Nb atom and alloying elements were taken into account in the prediction. The melting temperature was calculated readily by taking the compositional average of melting temperatures for constituent metals, and used as an indication for the creep strength of alloys. The corrosion resistance to liquid Na was also found to be significantly lower in the Nb-based alloys than in the Mo-based alloys. In addition, the corrosion resistance of Nb-based alloys were largely varied with alloying elements. From a series of corrosion tests with various Nb-M binary alloys, alloying elements which are effective in improving the corrosion resistance were selected. Furthermore, alloy densities were estimated by taking the compositional average of the densities for constituent metals in alloy. Based on these results, a Nb-W-V-Zr system was selected as the most promising alloy for nuclear power plants. The specific properties were estimated with varying alloy compositions, even though extensive investigation is further needed to draw a conclusion on the corrosion resistance of these alloys. Finally, it was concluded that the present predicting method could provide an useful indication for the efficient design of Nb-based alloys. (author)

1994-07-01

99

Design of super heat-resisting Mo-based alloys for nuclear applications  

International Nuclear Information System (INIS)

Mo-based alloys are promising the candidate materials for structural applications in the advanced nuclear power system. In order to obtain some indication for the alloy design, the high-temperature tensile strength, high-temperature creep strength, corrosion resistance to liquid metal and alloy density were investigated systematically in this study. The high-temperature micro-hardness was measured with binary, ternary and some multi-components alloys, and found to be predictable using the differences in atomic radius and in Young's modulus between the Mo atom and the alloying element. The high temperature tensile strength was also predictable from the calculated micro-hardness of alloys. The melting temperature which was associated with the high temperature creep strength, was shown to be predicted by the d-electron parameters calculated by the DV-X? cluster method. The corrosion resistance in liquid sodium was found to be significantly higher for the Mo-based alloys than for Nb-based alloys. In addition, the alloy densities could be estimated readily by taking the compositional average of each densities for constituent metals in alloys. Based on these results, as Mo-Re-W-Zr system was selected as the most promising system, and its properties were estimated with varying alloy compositions. It was concluded that the present predicting method of alloy properties indeed provided a good indication for the efficient alloy design of Mo-based alloys. (author)

1993-02-01

100

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 SiO_2-B_2O_3 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

1980-05-01

 
 
 
 
101

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

International Nuclear Information System (INIS)

Highlights: ? 9Cr alloys with varying Ti and C contents were designed, produced and crept at 650 deg. C. ? Sub-grain and precipitate distribution and evolution investigated by STEM-HAADF. ? Correlations between microstructure evolution and mechanical properties were studied. ? Coarsening of sub-grain size was larger for Ti-containing 9Cr alloys. ? 9Cr alloy with low C and no Ti showed the highest creep strength of all studied alloys. - Abstract: In this work 9%Cr alloys were designed supported by computational thermodynamic methods. Two sets of alloys were produced: 9%Cr alloys with 0.1%C and 0.05%C and 9%Cr alloys containing ?0.03% Ti with 0.1%C and 0.05%C (always wt%). Microstructure investigations showed good agreement with the predicted phases of the thermodynamic modeling. The volume fraction of precipitated M23C6 carbides is directly related to the carbon content of the alloys. For Ti-containing alloys the precipitation of nano-sized Ti-rich MX carbonitrides was observed. The microstructure evolution (sub-grain and particle size) during creep at 650 deg. C/100 MPa was investigated by STEM-HAADF. The sub-grain size evolution and the coarsening of precipitates (MX carbonitrides, M23C6 and Laves phase) were more pronounced for Ti-containing alloys. 9Cr alloys without Ti and with low carbon content presented the highest creep strength of all investigated alloys.

2011-06-15

102

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

Energy Technology Data Exchange (ETDEWEB)

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)

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

2005-07-15

103

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

Energy Technology Data Exchange (ETDEWEB)

Highlights: {yields} 9Cr alloys with varying Ti and C contents were designed, produced and crept at 650 deg. C. {yields} Sub-grain and precipitate distribution and evolution investigated by STEM-HAADF. {yields} Correlations between microstructure evolution and mechanical properties were studied. {yields} Coarsening of sub-grain size was larger for Ti-containing 9Cr alloys. {yields} 9Cr alloy with low C and no Ti showed the highest creep strength of all studied alloys. - Abstract: In this work 9%Cr alloys were designed supported by computational thermodynamic methods. Two sets of alloys were produced: 9%Cr alloys with 0.1%C and 0.05%C and 9%Cr alloys containing {approx}0.03% Ti with 0.1%C and 0.05%C (always wt%). Microstructure investigations showed good agreement with the predicted phases of the thermodynamic modeling. The volume fraction of precipitated M{sub 23}C{sub 6} carbides is directly related to the carbon content of the alloys. For Ti-containing alloys the precipitation of nano-sized Ti-rich MX carbonitrides was observed. The microstructure evolution (sub-grain and particle size) during creep at 650 deg. C/100 MPa was investigated by STEM-HAADF. The sub-grain size evolution and the coarsening of precipitates (MX carbonitrides, M{sub 23}C{sub 6} and Laves phase) were more pronounced for Ti-containing alloys. 9Cr alloys without Ti and with low carbon content presented the highest creep strength of all investigated alloys.

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

2011-06-15

104

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

International Nuclear Information System (INIS)

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

1984-01-01

105

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

Energy Technology Data Exchange (ETDEWEB)

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 13CrMO{sub 4}-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.

W. Bendick; J. Gabrel; B. Hahn; B. Vandenberghe [Salzgitter Mannesmann Forschung GmbH, Duisburg (Germany)

2007-01-15

106

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

Energy Technology Data Exchange (ETDEWEB)

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.

Bendick, W. [Salzgitter Mannesmann Forschung GmbH, Ehinger Str. 200, 47259 Duisburg (Germany)]. E-mail: w.bendick@du.szmf.de; Gabrel, J. [Vallourec Research Center CEV, route de Leval, 59620 Aulnoye-Aymeries (France); Hahn, B. [V and M Deutschland GmbH, Theodorstrasse 90, 40472 Duesseldorf (Germany); Vandenberghe, B. [V and M France, 37 rue Henri Barbusse, 59880 Saint-Saulve (France)

2007-01-15

107

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

2007-01-01

108

High temperature crevice corrosion of heat-resistant Ni-base alloy in the simulated HTR helium  

International Nuclear Information System (INIS)

Interaction between a Ni-base heat-resistant alloy and the simulated HTR primary coolant environment was examined with emphasis on the reactions inside narrow crevice gaps. A new method using Mo crevice cells was developed to obtain reproducible quantitative results. The test environment was characterized by the low oxidizing species as trace gaseous impurities. Series of sequential phenomena were observed: i.e. the preferential consumptions of oxidizing species in the outer part of the crevice, followed by the lack of oxide film and the resultant extensive carburization further inside the crevice. A model on the possible phenomena occurring at tips of the cracks formed during creep or fatigue tests and low flow rate portions in the reactor primary circuit as well. The feasibility of the interpretation was checked referring to the existing numerical formula and using the experimental results obtained parameters. Calculations reproduced penetration curves of the Cr- oxidation with reasonable accuracy. (author)

1980-01-01

109

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

2006-11-05

110

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.)

1986-01-01

111

Study on thermal treatment regime effect on the phase content of heat resisting alloys  

International Nuclear Information System (INIS)

The changes are studied in nickel-chrome alloys on heat treatment and ageing by using the method of electrochemical phase separation with measurement of the amount of segregated ?-phase and its parameter Eh1437BUVD, EhI1698VD and ZhS6-KP alloys were used for the study. The amount of ?-phase in nickel-chrome-based alloys changes in the course of ageing only in the initial period up to 4 hr. The cooling rate on hardening affects the amount of ?-phase, i.e. the higher the rate, the lower is the content of ?-phase. An increase in the time of holding at the hardening temperature increases the amount of strengthening phase

1977-01-01

112

Corrosion behavior of Nb-based and Mo-based super heat-resisting alloys in liquid Li  

International Nuclear Information System (INIS)

Research on structural materials which will be utilized even in the severe environment of high-temperature liquid alkali metals has been promoted in order to develop the frontiers of materials techniques. The super-heat resisting alloys which are based on refractory metals, Nb and Mo, are aimed as promising materials used in such an environment. The corrosion resistance in liquid Li and the mechanical properties such as creep and tensile strengths at high temperatures are important for these structural materials. On the basis of many experiments and analyses of these properties at 1473 K, the material design of Nb-based and Mo-based alloys has been carried out successfully. In this report, all the previous experimental results of corrosion tests in liquid Li were summarized systematically for Nb-based and Mo-based alloys. The corrosion mechanism was proposed on the basis of a series of analyses, in particular, focussing on the deposition mechanism of corrosion products on the surface and also on the initiation and growth mechanism of cracks on the corroded surface of Nb-based alloys. The principal results are as follows. (1) For the deposition mechanism, a reaction took place first between dissolved metallic elements and nitrogen which existed as an impurity in liquid Li and then corrosion products (nitrides) precipitated on the metal surface. Subsequently, another reaction took place between dissolved metallic elements in liquid Li, and corrosion products (intermetallic compounds) precipitated on the metal surface. The composition of deposited corrosion products could be predicted on the basis of the deposition mechanism. (2) For the crack initiation mechanism, the chemical potential diagrams were utilized in order to understand the formation of Li-M-O ternary oxides which caused cracks to be formed on the corroded surface. Consequently, it was evident that not only the concentration of the dissolved oxygen in the alloy but also the concentration of Li which penetrated through the alloy was very important in understanding the crack formation on the surface of Nb-based alloys. (author)

1998-01-01

113

Corrosion behavior of Nb-based and Mo-based super heat-resisting alloys in liquid Li  

Energy Technology Data Exchange (ETDEWEB)

Research on structural materials which will be utilized even in the severe environment of high-temperature liquid alkali metals has been promoted in order to develop the frontiers of materials techniques. The super-heat resisting alloys which are based on refractory metals, Nb and Mo, are aimed as promising materials used in such an environment. The corrosion resistance in liquid Li and the mechanical properties such as creep and tensile strengths at high temperatures are important for these structural materials. On the basis of many experiments and analyses of these properties at 1473 K, the material design of Nb-based and Mo-based alloys has been carried out successfully. In this report, all the previous experimental results of corrosion tests in liquid Li were summarized systematically for Nb-based and Mo-based alloys. The corrosion mechanism was proposed on the basis of a series of analyses, in particular, focussing on the deposition mechanism of corrosion products on the surface and also on the initiation and growth mechanism of cracks on the corroded surface of Nb-based alloys. The principal results are as follows. (1) For the deposition mechanism, a reaction took place first between dissolved metallic elements and nitrogen which existed as an impurity in liquid Li and then corrosion products (nitrides) precipitated on the metal surface. Subsequently, another reaction took place between dissolved metallic elements in liquid Li, and corrosion products (intermetallic compounds) precipitated on the metal surface. The composition of deposited corrosion products could be predicted on the basis of the deposition mechanism. (2) For the crack initiation mechanism, the chemical potential diagrams were utilized in order to understand the formation of Li-M-O ternary oxides which caused cracks to be formed on the corroded surface. Consequently, it was evident that not only the concentration of the dissolved oxygen in the alloy but also the concentration of Li which penetrated through the alloy was very important in understanding the crack formation on the surface of Nb-based alloys. (author)

Saito, J.; Kano, S. [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center; Morinaga, M.

1998-07-01

114

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

International Nuclear Information System (INIS)

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

1980-01-01

115

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)

1980-01-01

116

Creep-rupture properties of Incoloy 800H, 2-1/4 Cr-1 Mo, and Hastelloy X alloys in simulated HTGR environment  

International Nuclear Information System (INIS)

Results of creep-rupture tests performed in a simulated HTGR helium environment (design basis helium) are presented and compared with available air data for Incoloy 800H, Hastelloy X, and 21/4 Cr--1 Mo steel. Tests were performed at temperatures representative of HTGR operating conditions for each alloy (900 to 16000F). Test durations to date were generally less than 4000 h. Results indicate that creep-rupture properties of these alloys in the test environment are consistent with the expected properties in air. Additional tests of 10,000 h duration are planned. 10 figures, 4 tables

1976-01-01

117

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

1978-01-01

118

Gaseous hydrogen effect on strength and ductility of nickel heat resisting alloys  

International Nuclear Information System (INIS)

A study was made on hydrogen effect on mechanical properties of KhN55MBYu and KhN60MVYu alloys. Tensile tests were conducted in 290-1073 K range in 0.13 Pa vacuum and in hydrogen under 35 MPa pressure. It was established that hydrogen effect is manifested by decrease of plasticity and the change of a fracture mode from transcrystalline to intercrystalline, intensifies with increase of strengthening ?'-phase quantity and terminates at 1073 K

1984-01-01

119

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 871"0C 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 538"0C

1981-05-05

120

Structural transformations in heat-resistant protective coatings on nickel alloys  

Energy Technology Data Exchange (ETDEWEB)

A study is made of the structural and phase transformations occurring in fused slurry aluminosilicide coatings (Al-Si and Al-Nb-Si) and in an electron-beam-deposited Co-Cr-Al-Y coating on EP-539 alloy during high-temperature and corrosion testing and during service. A model is developed which describes the disintegration of these coatings resulting from structural changes due to high-temperature gas corrosion. The role of the martensitic transformation of the beta phase (NiAl) in the deterioration of aluminosilicide coatings is examined. 9 references.

Veksler, IU.G.; Lesnikov, V.P.; Paleeva, S.IA.; Lesnikova, E.G.; Mial' nitsa, G.F.

1987-01-01

 
 
 
 
121

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

International Nuclear Information System (INIS)

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

1983-01-01

122

Thermal fatigue and endurance of welded joints of chromium-nickel heat resistant alloys  

International Nuclear Information System (INIS)

Investigated is the effect of initial metal structure, heat treatment before and after the welding, deformations in a course of weld rolling, stress concentrations in a form of flash or notches arising in a course of weld trimming, on the thermal fatigue and endurance of welded joints of KhN56VMTJu (EhP-199) and Kh15M30VMT precipitation-hardening alloys. Thermal fatigue tests have been carried out under conditions of 200 deg reversible 8O0 deg C and 200 deg reversible 1000 deg C. Initial coarse grain and rough weld trimming are shown to decrease endurance and thermal fatigue. Thermal treatment according to the regime: quenching from 1150 deg C + ageing at 950 deg C during 5 hours for Kh56 VMTJu steel and quenching from 1120 deg C + ageing at 750 deg C during 16 hours for Kh15M30VMT provides strength a full-strength joint

1979-11-01

123

Magnetron sputter deposition of heat-resistant coatings on high temperature alloys  

Energy Technology Data Exchange (ETDEWEB)

The experiments were carried out in a unit with two planar magnetrons arranged acording to a scheme of the 'face-to-face' type. Co-Cr-Al-Y coatings were applied on specimens for mechanical and thermal fatigue, longterm strength and sulphidation-oxidation corrosion tests as well as for metallographic study. It was established that coating increases the corrosion resistance of alloys without any deterioration of their service properties. It has been shown that layer-by-layer alternation of CoAl and Co(CrAl) phases in Co-Cr-Al-Y coatings improves the high temperature fatigue properties of the substrate. The use of high substrate bias during coating deposition leads to changes in the coating chemical composition along the blade profile. In this case the chromium content, for example, is inversely dependent upon the ion current density. (orig.).

Beregovsky, V.V.; Shergin, G.G.; Shesterkin, N.G.; Kuznetsov, E.V.; Anisimova, M.A. (NPO Cniitmash (USSR))

1991-10-01

124

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

Directory of Open Access Journals (Sweden)

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

Wang Haitao

2009-05-01

125

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 H_2SO_4 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 H_2SO_4 solution shows the following effects: the critical passivation current density and the passive current density increase with increasing chloride concentration and both, the critical pitting potentials and the pitting nucleation potentials, shift towards negative values. As third parameter the pH-value was varied. As expected, an increase of the pH-value extends the passive region to more negative values, the passive current density decreases. The variation of the pH-value does not affect the critical pitting potential. All tested alloys showed a clearly limited resistance against pitting corrosion phenomena. However, the best corrosion behaviour is shown by HASTELLOY C4, which has of all tested alloys the lowest passivation current density and the largest potential region with protection against local corrosion phenomena. (author)

1987-05-01

126

High temperature strength of hastelloy XR electron beam weld metal  

International Nuclear Information System (INIS)

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

1986-01-01

127

Investigation into effect of chemical composition changes of nickel powder heat resisting alloy on the temperature of absolute dissolution of ?' phase  

International Nuclear Information System (INIS)

The effect of the chemical composition changes of nickel powder alloy on the temperature of absolute dissolution of ?' phase is studied. Ten melts of nickel powder heat resisting alloy of the Ni-Cr-Co-Al-Ti-W-Mo-Nb system have been taken as the material of investigation. Temperatures of absolute dissolution of the above alloy, differed in the content of alloyed components within the limits of the grade composition, are determined with the use of metallographical and resistant-metrical analyses. Using the method of ''accidental balance'' established is a dependence between changes (within the limits of the grade composition of the alloy) in the content of alloyed components and the temperature of absolute dissolution of ?' phase

1980-01-01

128

Relationship of H2O and CH4 supply rates in HTGR helium to the carburization of Hastelloy-X and alloy 800H  

International Nuclear Information System (INIS)

A detailed study of the carburization of Hastelloy-X and alloy 800H in high-temperature gas-cooled reactor helium was made to determine the cause of the wide variability of data generated in retorts. Data for 10000C and 2500-h exposure show that up to an order of magnitude difference in the carburization levels can be caused by changes in the flow rate of the test gas and/or the position of the corrosion specimen in the gas stream. The results are unambiguously explained by the parameters S(H2O) and S(CH4), the supply rates of water and methane, respectively

1984-01-01

129

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

International Nuclear Information System (INIS)

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

130

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)

1988-01-01

131

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

International Nuclear Information System (INIS)

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

1979-01-01

132

Effects of microstructures and creep conditions on the fractal dimension of grain boundary fracture in high-temperature creep of heat-resistant alloys  

International Nuclear Information System (INIS)

The effects of microstructural aspects, such as grain size and grain boundary configuration, and creep conditions on the fractal dimension of the grain boundary fracture were examined using several heat-resistant alloys, principally in an analysis scale range between one grain boundary length and specimen size. Grain boundary fracture surface profiles in the heat-resistant alloys exhibited a fractal nature in the scale range between one grain boundary length and specimen size as well as in the scale range below one grain boundary length. The fractal dimension of the grain boundary fracture slightly increased with decreasing grain size and was generally a little larger in the specimens with serrated grain boundaries than in those with straight grain boundaries. The fractal dimension of the grain boundary and the number of grain boundary microcracks which affected the grain boundary fracture patterns were a little larger in the specimen with the smaller grain size, and were also larger in the specimen with serrated grain boundaries. The fractal dimension of the grain boundary fracture increased with decreasing creep stress in the temperature range from 973 to 1422 K in these alloys, since more grain boundary microcracks existed in the specimens ruptured under the lower stresses at the higher temperatures. (orig.)

1993-10-01

133

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

1983-06-01

134

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

International Nuclear Information System (INIS)

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

1987-01-01

135

High-Temperature tensile and creep properties of hastelloy-X superalloy for the HTGR  

International Nuclear Information System (INIS)

The design of the metallic components for a High Temperature Gas cooled Reactor (HTGR) such as hot gas ducts, Intermediate Heat eXchanger (IHX) tube, and steam reformer tubes is principally carried out using the mechanical strength values of the tensile and creep properties. Elevated tensile and creep data for candidate alloys are needed to design the structural components operated at 900 to 1000 .deg. C. Hastelloy-X is a candidate heat-resistant alloy for the HTGR. In this study, the tensile and creep properties were investigated at the high temperature test conditions; 600 to 1000 .deg. C in tensile and 950 .deg. C in creep. A lot of data were collected through literature survey, and the data were analyzed in the viewpoint of the design of the HTGR structures. The fractured micrographs were also observed

2005-11-02

136

Effects of stress aging on changes in mechanical properties and microstructures of Hastelloy-X and Hastelloy-XR  

International Nuclear Information System (INIS)

Mechanical property and Microstructural changes of Ni-base super alloys after aging with and without tensile stress were observed in the temperature range of 500-1000"0C for durations to 305 hr. The materials tested are Hastelloy-X and its modified heat (Hastelloy-XR). Changes of the mechanical properties are appreciably enhanced by the application of stress during the aging. The changes are interpreted in connection with microstructural changes due to the enhanced carbide precipitation caused by the stress aging. Commercial grade Hastelloy-X is found to be more influenced by the stress than Hastelloy-XR. (auth.)

1977-01-01

137

New heat resisting alloys on the nickel base for application at the temperature up to 1200 deg C  

International Nuclear Information System (INIS)

A new alloy Nicrofer 6025 HT (25 % Cr; 10 % Fe; 2 % Al; 0.2 % C; 0.1 % Y; the rewaining - Ni) which features a high long-term strength, though it has no expensive alloying elements. Nicrofer 6025 HT alloy combines a high long-term strength and oxidation resistance

1993-01-01

138

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

International Nuclear Information System (INIS)

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

2010-06-01

139

Optimization of the composition and structure of heat-resistant casting aluminium alloys with additions of cerium, iron, nickel and zirconium  

International Nuclear Information System (INIS)

A study is made of the effect of composition and structure on mechanical properties of cast alloys of the Al-Ce-Ni-Fe-Zr system in which binary and ternary eutectics with participation of low alloyed aluminium solid solution and Al4Ce, Al3Ni and Al9FeNi phases are crystallized. It is found that microhardness of eutectics is heavily dependent on the volume fraction of aluminides and their dispersivity. It was shown that essential hardening of aluminium matrix can be achieved at the cost of zirconium additive in quantity of 0.6 % when using two-stage manufacturing operation. Experimental compositions of Al-10 % Ce-5% Ni-0.6 % Zr and Al-1.5 % Fe-1.5 % Ni-0.6 % Zr on the basis of ternary and binary eutectics respectively as billets essentially exceed industrial heat-resistant cast aluminium alloys AK12MMgN and AM5 as to a set of room and high-temperature mechanical properties and hot brittleness index

2000-01-01

140

Effect of heat treatment temperature on creep properties of Hastelloy XR  

International Nuclear Information System (INIS)

Effect of heat treatment temperature on creep properties was studied for Hastelloy XR and XR-II developed as heat resistant alloys for high temperature gas cooled reactors. The effect of heat treatment temperature was divided into that of grain size and that of solution treatment. Each effect could be examined separately by using specimens after a two-stage heat treatment. Although creep rupture time and steady-state creep rate at 700 deg C depended on only solution treatment, those at 900 deg C depended on both grain size and solution treatment. It was estimated that influences of about ± 20 % on creep rupture time were given in the case of short-term creep rupture tests at 900 deg C if there were differences of ± 15 deg C among heat treatment temperatures of materials. (author)

1988-01-01

 
 
 
 
141

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

International Nuclear Information System (INIS)

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

1979-01-01

142

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1991-06-01

143

Main ways of heat resistant steels design  

International Nuclear Information System (INIS)

Main directions of development of heat resistant steels including including new approaches and methods both in part of structural investigations and in the field of applying more perfect technological processes of their production and treatment are considered. The necessity of preparing materials for nuclear and thermonuclear engineering with a special complex of mechanical properties is underlined. Austenitic steels and ferritic steels with the Curie point close to room temperature are considered as promising materials for first wall of TNR. A possibility of using high-alloyed nickel alloys is considered for high temperature heat exchangers. Primary attention is paid to heat resistant pearlitic steels and methods of their substructural hardening for an essential increase of creep resistance and long-term rupture strength. Perspectiveness of applying powder metallurgy methods, thermomechanical treatment, microalloying and nitrogen substitution in steels for carbon is revealed. The necessity of reinforcing coordination of research works in the field of heat resistant alloys is noted

1982-01-01

144

Structure and mechanical properties of heat resistant nickel KhN62BMKTYu alloy melted by various techniques  

International Nuclear Information System (INIS)

The structure and properties of nickel base KhN62BMKTYu were studied for the metal produced by the following methods: vacuum induction melting with vacuum are, remelting, electron beam melting, plasma arc melting with vacuum arc remelting. The investigation results showed that the alloy type KhN62BMKTYu possesses high ductility and is applicable for long-term service at high temperatures. It was concluded that all the melting methods ensure high metal quality

1993-01-01

145

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)

1982-01-01

146

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

International Nuclear Information System (INIS)

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

1993-02-01

147

High resolution SEM fractography of Te-embrittled Hastelloy-N  

International Nuclear Information System (INIS)

An alloy development program directed toward modification of Hastelloy-N (16 percent Mo--7 percent Cr--4 percent Fe--0.55 percent Mn--0.06 percent C--bal Ni) to improve its resistance to radiation damage is described. Fractographs are presented for Hastelloy-N after various modifications and exposures

1976-08-09

148

Heat-resisting steels  

International Nuclear Information System (INIS)

The main part of this work is high temperature corrosion by hot gases or molten sats. In order to have a better understanding of alloying techniques, the kinetic and thermodynamic interrelations of high temperature corrosion are explained. (IHOE)

1981-11-26

149

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)

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.)

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

2013-03-15

150

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

1982-01-01

151

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

Energy Technology Data Exchange (ETDEWEB)

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 871/sup 0/C 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 538/sup 0/C. An analysis is also presented of the continuous cycle fatigue data obtained from room temperature to 427/sup 0/C for Hastelloy G, Hastelloy X, Hastelloy C-276, and Hastelloy C-4, an effort undertaken in support of ASME code development.

Strizak, J.P.; Brinkman, C.R.; Booker, M.K.; Rittenhouse, P.L.

1982-04-01

152

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

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

SAE Aerospace Standards. London

2012-01-01

153

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

1977-05-01

154

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

1997-01-01

155

Caburisation of heat-resistant steels  

Energy Technology Data Exchange (ETDEWEB)

The effects of alloying additions of silicon, molybdenum, reactive elements (Ti, Y, Ta, Hf, Nb, Zr), and aluminium, in cast, heat-resistant steels on their carburisation resistance have been investigated at temperatures of 900 to 1150 C. Under strongly reducing conditions, where neither silicon nor chromium oxidise, it is found that the alloying additions slow carburisation rates significantly. In the case of molybdenum and reactive elements, the beneficial effect is attributed to diffusional blocking of carbon flux due to the formation of carbide precipitates of these elements. Silicon operates by altering the solubility and diffusivity of carbon in the matrix. Aluminium appeared to exclude carbon almost completely from the alloy, probably by forming a tenacious external oxide scale. Comparison between a wrought and a cast alloy showed that the cast alloy was more resistant to carburisation. Under conditions oxidising to silicon and chromium, but not to iron and nickel, carburisation rates are slower. The most important factor is then alloy silicon content, which controls the formation of an external SiO{sub 2} layer. (orig.) 25 refs.

Mitchell, D.R.G.; Young, D.J. [New South Wales Univ., Sydney, NSW (Australia). School of Materials Science and Engineering; Kleemann, W. [Schmidt und Clemens GmbH Kaiserau, Lindlar (Germany)

1998-04-01

156

Creep properties of Hastelloy-X in impure helium environments  

International Nuclear Information System (INIS)

In impure helium environments, Hastelloy-X is susceptible to carburization and oxidation. These effects are investigated separately, and are related to the creep behavior of the alloy. Experiments were carried out at 9000C in both helium and air. Carburization resulted in a slight increase of the creep strength up to the onset of the tertial creep. Suppression of the creep crack growth by oxidation was confirmed using notched plate specimens of Inconel alloy 600 and Hastelloy-X. Although the difference of creep strength in air and in helium was very small and considered to be inclusive in the usual scatter, a pessimistic ratio of rupture stress in helium to that in air was estimated to be 0.9

1984-01-01

157

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

1989-06-01

158

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)

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.

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

159

Evaluation of weldability of hastelloy XR  

Energy Technology Data Exchange (ETDEWEB)

Hastelloy XR has been developed in Japan Atomic Energy Research Institute to improve the corrosion resistance of Hastelloy X in VHTR helium environment. To evaluate weldability of Hastelloy XR, bead welding tests by EB welding and Trans-Varestraint tests by TIG welding were carried out. The results obtained are as follows. (1) The weld defects formed in the bead welding test by EB welding were R-porosity and microcracks, both of which are the same as in Hastelloy X. R-porosity and microcracks can be prevented by using a proper asub(b) value and by controlling the weld heat input, respectively. (2) In the Trans-Varestraint test by TIG welding, susceptibility to weld cracking was the same for both Hastelloy XR and Hastelloy X. To eliminate microcracking in TIG welding, it is effective to decrease the welding current.

Shimizu, Shigeki; Satoh, Keisuke (Kawasaki Heavy Industries Ltd., Kobe (Japan)); Mutoh, Yasushi; Ogawa, Yutaka

1983-12-01

160

Evaluation of weldability of hastelloy XR  

International Nuclear Information System (INIS)

Hastelloy XR has been developed in Japan Atomic Energy Research Institute to improve the corrosion resistance of Hastelloy X in VHTR helium environment. To evaluate weldability of Hastelloy XR, bead welding tests by EB welding and Trans-Varestraint tests by TIG welding were carried out. The results obtained are as follows. (1) The weld defects formed in the bead welding test by EB welding were R-porosity and microcracks, both of which are the same as in Hastelloy X. R-porosity and microcracks can be prevented by using a proper asub(b) value and by controlling the weld heat input, respectively. (2) In the Trans-Varestraint test by TIG welding, susceptibility to weld cracking was the same for both Hastelloy XR and Hastelloy X. To eliminate microcracking in TIG welding, it is effective to decrease the welding current. (author)

1983-01-01

 
 
 
 
161

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

International Nuclear Information System (INIS)

A new heat resistant Fe-Ni-Cr-W alloy - Thermon 4972 - was developed within the scope of the prototype nuclear process plant project. This new alloy not only shows mechanical properties and creep rupture properties similar to those of the nickel-based alloy Inconel 617 but in addition, the new alloy forms protective oxide layers in atmospheres with very low O_2 partial pressures. Experimental test results carried out in so called PNP-helium for durations up to 2000 h in the temperature range of 750 and 950 deg. C are compared with those of the alloy Inconel 617. Furthermore the mechanical properties of these two alloys as also the alloys Hastelloy X and Incoloy 800 H have been compared. (author). 5 refs, 18 figs, 2 tabs

1989-06-01

162

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

Science.gov (United States)

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.

Ouyang, Fan-Yi; Chang, Chi-Hung; Kai, Ji-Jung

2014-03-01

163

Nitrogen effect on heat resistance and structure of subscale layer of chromium-manganese steel  

International Nuclear Information System (INIS)

The possibility of achieving high heat resistance with conservation of austenite structure under the scale was investigated. For this purpose chrome-manganese steel was alloyed by nitrogen-strong #betta#-stabilizer. Nitrogen effect on component distribution in subscale layer and depth of this layer, as well as heat resistance of alloys with preliminarily prepared surface ?-layer and without it were studied. It was established that at 0.55-0.60% nitrogen content high heat resistance is achieved and austenite structure is conserved under the scale; it must promote the increase of contant strength

1982-01-01

164

Application of Hastelloy X in Gas-Cooled Reactor Systems  

DEFF Research Database (Denmark)

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.

Lystrup, Aage

1976-01-01

165

Oxidation of Hastelloy C276  

International Nuclear Information System (INIS)

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

2002-05-15

166

Oxidation of Hastelloy C276  

Science.gov (United States)

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

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

2002-05-01

167

The effects of helium on hydrogen isotope retention in Hastelloy-N  

Science.gov (United States)

Thermal desorption spectrometry was used to investigate the temperature range of hydrogen isotope retention in a Hastelloy-N type alloy that had previously been implanted with helium. Helium implanted in the dose range from 1 × 10 16 to 1.2 × 10 17 He/cm 2 provided additional traps for retention of hydrogen, with the hydrogen release temperature increasing as the implanted helium dose increased. The step character of the release and retention processes bears witness to the presence of two-phase states in the Hastelloy-helium system.

Neklyudov, I. M.; Morozov, O. M.; Kulish, V. G.; Azhazha, V. M.; Lavrinenko, S. D.; Zhurba, V. I.

2011-10-01

168

Fundamental studies on electron beam welding on heat-resistant superalloys for nuclear plants, 7  

International Nuclear Information System (INIS)

In this paper, the environmental effect of weld zone of heat-resistant superalloys by aging in high temperature helium was examined. Obtained conclusions are summarized as follows: 1) Hastelloy X showed the most smallest weight gain among the materials used, and no difference was discovered among the base metal, the electron beam weld joints and TIG weld joints for the respective materials. 2) Regarding the internal oxidation resistance, the electron beam weld metal was equivalent to or superior to the base metal, while the TIG weld metal was generally inferior to it. Among the materials used, Hastelloy X showed the most excellent internal oxidation resistance. 3) The oxide film of Hastelloy X showed the most excellent adherence property among the materials used. 4) Concerning the precipitation process of carbides, it followed the precipitation and cohesion with a rise in aging temperature and a lapse of aging time, and a change in hardness corresponded to it. However, notable difference in precipitation process was not noted among the base metal, electron beam weld metal and TIG weld metal. (author)

1980-01-01

169

The corrosion behavior of molybdenum and Hastelloy B in sulfur and sodium polysulfides at 623 K  

International Nuclear Information System (INIS)

An experimental study was completed to determine the corrosion behavior of molybdenum and Hastelloy B, a nickel-based alloy with high molybdenum content, in sulfur and sodium polysulfides (Na/sub 2/S/sub 3/,Na/sub 2/S/sub 4/, Na/sub 2/S/sub 5/) at 623 K. In sulfur, molybdenum corrodes very slowly, with a parabolic rate constant of 3.6 x 10/sup -9/ cm s/sup -1/2/. Hastelloy B shows no measurable corrosion after 100h of exposure to sulfur. The corrosion reaction of molybdenum in Na/sub 2/S/sub 3/ is characterized by the formation of a protective film that effectively eliminates further corrosion after the first 100h of exposure. Hastelloy B, however, corrodes rapidly in Na/sub 2/S/sub 3/, with corrosion rates approaching those of pure nickel under the same conditions. After the first 4h of exposure, the kinetics for the corrosion of Hastelloy B in Na/sub 2/S/sub 3/ follows a linear rate law. The scale morphology has multiple spalled layers of NiS/sub 2/, with some crystallites of NiS/sub 2/ appearing on the leading face of the scale and between the individual scale layers. This spalling causes smaller coupons of the Hastelloy B to corrode faster than larger coupons

1987-01-01

170

The oxidation behaviour of heat resisting metallic fibres  

International Nuclear Information System (INIS)

The behaviour of 22 ?m diameter alloy fibres of Type 310 stainless steel, Hastelloy X, Inconel 601 and Fecralloy has been studied at 6000C in combustion gases with and without HCl addition. Chromia-forming alloys exhibited higher rates of attack than would have been expected from a consideration of the properties of the bulk material whereas normal rates of attack were observed for alumina-forming alloys. The addition of HCl to the combustion gases increased rates of attack for all alloys and generally this was associated with increased sulphur in the oxide layer. The results are discussed with reference to the unusual geometry of the samples, and it is suggested that the direction of motion of the ions in the growing oxide layer is an important factor governing its protective nature. Alloy depletion effects were also noted, particularly for some Fecralloy samples which were pre-oxidized before exposure, and this may cause eventual failure of the protective oxide. A common feature of the oxidation of iron-chromium alloys is the partitioning of elements in the scale; this was especially marked for the Type 310 stainless steel samples exposed in this work and a stress-assisted diffusion process is proposed to explain this effect. (author)

1983-01-01

171

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)

1979-01-01

172

Phase precipitation and time-temperature-transformation diagram of Hastelloy  

International Nuclear Information System (INIS)

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

2000-11-30

173

Effect of alloying with TiC, NbC and TiN on heat-resistance of NiAl alloy produced by high-temperature synthesis compacting  

International Nuclear Information System (INIS)

By self-propagating high-temperature synthesis (SHS)-compacting the composition materials based on intermetallic compound NiAl alloyed by fine particles of TiC, NbC, and TiN (up to 20 wt.%) were obtained. The thermal stability of these materials at 1000 deg C for 350 h was investigated. The alloying of NiAl by TiC and NbC particles decreases the thermal stability, and TiN sharply increases it. The thermal stability increasing is explained by TiNO particles formation in Al2O3 scale. Particles of TiNO refine the grains of Al2O3 and increase its adhesion by anchor-type mechanism

1998-01-01

174

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)

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.

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

2006-10-15

175

Heat Resistance Requirements for Firefighters' SCBA.  

Science.gov (United States)

The lack of requirements for heat resistance evaluation of the facepiece of self-contained breathing apparatus (SCBA) for firefighters is discussed in the context of certification testing by manufacturers or regulatory agencies. Also, no distinction is ac...

H. T. Everett

1977-01-01

176

Mineralization and heat resistance of bacterial spores.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The heat resistances of the fully demineralized H-form spores of Bacillus megaterium ATCC 19213, B. subtilis var. niger, and B. stearothermophilus ATCC 7953 were compared with those of vegetative cells and native spores to assess the components of resistance due to the mineral-free spore state, presumably mainly from dehydration of the spore core, and to mineralization. Mineralization greatly increased heat resistance at lower killing temperatures but appeared to have much less effect at high...

Marquis, R. E.; Bender, G. R.

1985-01-01

177

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

2005-01-30

178

Permeability of hydrogen and deuterium of Hastelloy XR  

International Nuclear Information System (INIS)

Permeation of hydrogen isotope through a high-temperature alloy used as heat exchanger and steam reformer pipes is an important problem in the hydrogen production system connected to be a high-temperature engineering test reactor (HTTR). An experiment of hydrogen (H2) and deuterium (D2) permeation was performed to obtain permeability of H2 and D2 of Hastelloy XR, which is adopted as heat transfer pipe of an intermediate heat exchanger of the HTTR. Permeability of H2 and D2 of Hastelloy XR were obtained as follows. The activation energy E0 and pre-exponential factor F0 of the permeability of H2 were E0=67.2±1.2 kJ mol-1 and F0=(1.0±0.2)x10-8 m3(STP) m-1 s-1 Pa-0.5, respectively, in the pipe temperature ranging from 843 K (570 deg. C) to 1093 K (820 deg. C). E0 and F0 of the permeability of D2 were respectively E0=76.6±0.5 kJ mol-1 and F0=(2.5±0.3)x10-8 m3(STP) m-1 s-1 Pa-0.5 in the pipe temperature ranging from 943 K (670 deg. C) to 1093 K (820 deg. C)

2004-03-01

179

Development of a Mathematical Model of Crevice Corrosion Propagation on Nickel Base Alloys in Natural and Chlorinated Sea Water.  

Science.gov (United States)

Crevice corrosion initiation and propagation of nickel base alloys Inconel 625, Hastelloy C276 and Hastelloy 22 in sea water and chlorinated sea water has been studied by exposure tests, electrochemical studies, surface analysis and mathematical modelling...

J. W. Oldfield

1994-01-01

180

Alloys For Flexible Hoses In A Corrosive Environment  

Science.gov (United States)

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.

Macdowell, Louis G., III; Ontiveros, Cordelia

1992-01-01

 
 
 
 
181

Firefighters' SCBA: Belt Radiant Heat Resistance.  

Science.gov (United States)

Belts of firefighters' self contained breathing apparatus (SCBA) were analyzed for heat resistance. Elongation and stiffness were measured at heat intensities of 0.43, 0.92, and 1.16 watts per square centimeter. A simulated environment was achieved by kee...

K. G. Crouch

1980-01-01

182

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

1980-01-01

183

Oxidation of carburized Hastelloy X  

International Nuclear Information System (INIS)

In a high temperature gas-cooled reactor (HTGR), small quantities of impurities such as H2, H2O, CO, CO2, and CH4 are present in the helium coolant. Prolonged exposure to these impurities at high temperature can result in undesirable mechanical properties due to corrosion. Extensive research has been performed on many candidate alloys to study their properties in HTGR helium, and in addition to oxidation, it has been found that carburization is also a possible problem in HTGR. Carbon in the graphite core, carried out by carbon-containing impurities such as CO and CH4, can deposit on and diffuse into metallic components and cause carburization. The purpose of this research was to study the effects of carburization on an accelerated test

1983-01-01

184

Isolation, Identification of Heat Resistant Moulds in Margarine and Determination of Their Heat Resistance  

Directory of Open Access Journals (Sweden)

Full Text Available In this study, moulds that cause problems in a margarine production plant which is located in Trakyaregion have been isolated and identified. In addition to, their heat resistance and lipolytic activity werestudied. For this purpose, margarine samples from various production lots and process water samples fromproduction plant were taken aseptically, transported immediately to the laboratory and analyzed. In thisresearch, two different heat resistant mould strains have been isolated from margarines and process water.After identification of this moulds, their heat resistances at different temperatures have been investigated.Mould isolates were identified as heat resistant Aspergillus fumigatus, Paecilomyces variotii based onmacroscopic and microscopic features. To this analyses results about thermal resistance, Aspergillusfumigatus and Paecilomyces variotii were ability to survive heat treatment at 95oC 10 minutes and 90oC 10minutes, respectively.

A. S. Demirci

2006-09-01

185

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)

1987-01-01

186

Hydrogen permeation through nickel and Hastelloy X  

International Nuclear Information System (INIS)

Hydrogen permeation through materials is one of the major problems in the fusion reactor design. In this study, hydrogen permeabilities of nickel and Hastelloy X were measured with a permeation method. For nickel, the dependence of hydrogen permeability on hydrogen pressure and sample thickness was investigated systematically, and for Hastelloy X, the effects of sample treatments, mainly heat treatment, were studied. Main results are as follows: (1) Hydrogen permeability in nickel was obtained within the temperature range of 473 to 973 K, the hydrogen pressure range of 3.4 x 102 to 8.67 x 104 Pa and the sample thickness of 0.20 to 0.80 mm, which is as follows: P = (5.94 +- 0.22) x 10-5 exp(-(51.5 +- 0.3)kJ.mol-1/RT)cm3(NTP).cm-1.s-1.Pasup(-1/2). (2) Because of the good reproducibility of the data, the effectiveness of the apparatus was established. (3) It was confirmed that the bulk diffusion is the rate-limiting step of hydrogen permeation through nickel and the dissolution of hydrogen into nickel depends on Sieverts' law. (4) Within the temperature range of 673 to 873 K, hydrogen permeabilities of Hastelloy X were obtained as follows: For a sample without heat treatment P = (5.62 +- 1.29) x 10-5 exp(-(58.2 +- 1.7)kJ.mol-1/RT)cm3(NTP).cm-1.s-1.Pasup(-1/2); for a sample heated at 1023 K for 30 h before measurements P = (3.14 +- 1.07) x 10-4 exp(-(75.3 +- 2.4)kJ.mol-1/RT)cm3(NTP).cm-1.s-1.Pasup(-1/2); for a sample heated at 1023 K for 100 h before measurements P = (3.27 +- 0.28) x 10-4 exp(-(71.6 +- 0.6)kJ.mol-1/RT)cm3(NTP).cm-1.s-1.Pasup(-1/2). (5) Activation energy of hydrogen permeation in Hastelloy X was increased by the heat treatments, and this was qualitatively explained connecting with some precipitates. (auth.)

1978-01-01

187

Torsional creep characteristics of Hastelloy X  

Energy Technology Data Exchange (ETDEWEB)

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

Suzuki, Michiaki; Shimakawa, Takashi; Honda, Yoshio

1987-11-01

188

On the relationship between structure dispersity and heat resistance of materials  

International Nuclear Information System (INIS)

The effect was investigated of the dispersity of structure and of the chemical composition of KhN45Yu alloy and of 12Kh18N10T and Kh25T steels upon their heat resistance at the temperature of 800 deg C in the air for up to 1000 h. The metallographic and the X-ray analyses were used in the investigations. It was shown that such alloying elements as aluminium and cerium raise the resistance to scaling of chromium-nickel alloys, whereas materials with a fine-grained structure oxidize to a lesser degree than the coarse-grained ones

1979-01-01

189

Effect of grain size on high temperature creep properties of Hastelloy X  

International Nuclear Information System (INIS)

The effect of grain size, ranged from 37 to 1220 ?m, on creep behavior of Hastelloy X was studied at temperatures of 950, 1000 and 1050"0C. A steady state creep rate, epsilon* sub(s) (*: radical), of the alloy decreased with the increase of the grain size, reached a minimum at the grain size of 100 -- 200 ?m, L sub(M), and increased with the increase of that. From measurements of friction stress (?sub(f)) and observations of microstructures, it is concluded that the increase in epsilon* sub(s) (*: radical) under a given applied stress with the decrease of the grain size is attributable to the increase of an effective stress, ?sub(e)(= ?sub(a) - ?sub(f)), where ?sub(a) is the applied stress). On the other hand, recrystallization induced by a high stress concentration at grain boundary triple points in the coarse-grained alloys seems to accelerate the creep. By comparing the results in the Hastelloy X with those in carbon free 17Cr-14Ni steel, it is suggested that the grain size dependence of the epsilon* sub(s) (*: radical) of the Hastelloy X having finer grains than L sub(M) is more remarkable than that of carbon free 17Cr-14Ni steel because of the decrease of fine precipitates within grains in the former alloy, while the dependence of the alloy having coarser grains than L sub(M) is minor than that of carbon free 17Cr-14Ni steel because of preventing the stress concentration at the triple points by the grain boundary precipitates. (author)

1981-01-01

190

Tensile properties of Hastelloy X and Incoloy 800 exposed to air and helium at high temperature  

International Nuclear Information System (INIS)

The effect of corroded surface layer on the tensile properties at room and high temperatures was studied for Hastelloy X and Incoloy 800 by comparing the properties of corroded specimens with those of aged specimens. Corroded specimens were those subjected to 3,000-h and 50,000-h exposures at 1,0000C to air and VHTR helium. A small effect of exposure was observed both to helium and air in the case of Hastelloy X. In the case of Incoloy 800, however, exposure to air was found to reduce tensile properties markedly whereas exposure to helium scarcely reduced. Metallographic observation indicated that reduction of tensile properties was caused by intergranular oxidation. The ratio of the tensile strength (corroded specimen/aged specimen) being plotted against the amount of intergranular oxidation, data of the two alloys were superimposed on the same curve. Ductility minimum point observed on the solution treated materials at intermediate temperature was not detected on the aged and the corroded Hastelloy X, but was detected on the aged and the corroded Incoloy 800. (author)

1978-01-01

191

Thermophysical Properties of Heat Resistant Shielding Material  

International Nuclear Information System (INIS)

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

2004-01-01

192

Permeability of hydrogen isotope through Hastelloy XR in the HTTR hydrogen production system  

International Nuclear Information System (INIS)

Permeation of hydrogen isotope through a high-temperature alloy as used heat exchanger and reformer tubes is an important problem in the hydrogen production system connected to be the high-temperature engineering test reactor (HTTR). The objective of this test is to investigate a governing process of hydrogen permeation and effective methods of reducing an amount of permeated hydrogen isotope through the tubes. This paper described the governing process of hydrogen permeation in the HTTR hydrogen production system and permeability of hydrogen and deuterium of Hastelloy XR. A diffusion process in a solid metal limited the amount of permeated hydrogen isotope in the HTTR hydrogen production system. An activation energy for hydrogen permeation of Hastelloy XR was almost equal to that of Hastelloy X. It was found that an oxide film produced during 140 h heating under helium gas circumference has an effect of reducing the amount of permeated hydrogen isotope. We obtained the permeability of hydrogen and deuterium for Hastelloy XR as follows. Hydrogen : Temperature=570-820degC, Partial pressure=1.06 x 102 - 3.95 x 103 Pa. Activation energy, E0 = 67.2 ± 1.2 (kJ·mol-1). Pre-exponential factor, F0 = (1.0 ± 0.2) x 10-4 (cm3 (NTP)·cm-1·s-1·Pa-0.5). Deuterium : Temperature = 670 - 820degC, Partial pressure : 9.89 x 102 - 4.04 x 103Pa. Activation energy, E0 = 76.6 ± 0.5 (kJ·mol-1). Pre-exponential factor, F0 = (2.5 ± 0.3) x 10-4 (cm3 (NTP)·cm-1·s-1·Pa-0.5). (author)

2000-03-01

193

On forecasting long-term rupture strength of dispersion-hardened heat resistant materials  

International Nuclear Information System (INIS)

Studied is the problem of forecasting long-term rupture strength of dispersion-hardened heat-resistant alloys. Studied have been the high-temperature long-term rupture srength of niobium alloys with dispersion and solid-solution hardening on the bases up to 1000 hours. An attempt is made to establish general regularities of changes of long-term rupture strength of heat-resistant materials. The long-term rupture strength forecasting is shown to be complicated by the bends observed at the ?=f(tau) curves. The forecasting of long-term rupture strength is possible only within the area with the stable material structure and rupture mode, where the time dependence curve in the adopted coordinate system has no bends

1979-01-01

194

Strain vs. strain rate relationships for Incoloy 800, Hastelloy X and Hastelloy N  

International Nuclear Information System (INIS)

Strain versus strain rate data for unirradiated and irradiated Incoloy 800, Hastelloy X, and Hastelloy N were collected and plotted. All readily available data, both biaxial and uniaxial, between 1200 and 14000F were included regardless of chemistries, heat treatment, aging effects, etc. Several general conclusions were drawn from these data: (1) For unirradiated material, the strain to rupture decreases with decreasing strain rate (below tensile rates). This is also seen in 316 SS. (2) There appears to be a minimum in the curves for uniaxial tests on irradiated material. No such minimum is apparent in the biaxial data. (3) Biaxially stressed specimens (unirradiated) tested at low strain rates give the most accurate prediction of what the stress rupture ductility may be following irradiation. (U.S.)

1970-01-01

195

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

International Nuclear Information System (INIS)

High temperature gas-cooled reactors (HTGRs) have many high-temperature sliding or contacting parts. Generally these can be divided into contact between metal parts in each other and contact between metal and graphite. The authors set out to clarify adhesion behavior between metal and metal, and to acquire techniques that effectively prevent adherence of various heat-resistant materials in high temperature helium gas environments. Hastelloy X, Incoloy 800, Inconel 625 and Inconel 601 were investigated in the experiments. The obtained result shows that the ZrO_2 coating using a plasma spray process is the most effective method to prevent adhesion of these materials at working temperatures in excess of 800"0C (1,470"0F). Subsequently the experimental results were actually applied in the design and fabrication of the Oarai Gas Loop 1 (OGL-1) and the High Temperature Gas Loop (HTGL) in the Japan Atomic Energy Research Institute. (author)

1980-01-01

196

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

1994-01-01

197

Study on the nickel-free high manganese austenitic heat resisting steel  

International Nuclear Information System (INIS)

This investigation is to develop the nickel-free high manganese austenitic heat resisting steel. The effect of alloying elements on the forgeability, microstructure, creep repture life, oxidation resistance, PbO corrosion resistance and sulfidation resistance was investigated. It was found that the 12M41 alloy whose composition was 12% Mn, 17% Cr, 4.5% W, 0.9% Mo, 0.3% Nb, 0.3% C, 0.6% N, 0.01% B exhibited good hot workability, creep rupture life and corrosion resistance. (author)

1981-01-01

198

Effect of temperature and strain rate on serrated flow behaviour of Hastelloy X  

Energy Technology Data Exchange (ETDEWEB)

Highlights: Black-Right-Pointing-Pointer Tensile serrated flow behaviour of Hastelloy X was examined. Black-Right-Pointing-Pointer A, A + B, B and C types of serrated flow behaviour have been observed. Black-Right-Pointing-Pointer Molybdenum solute has been found to be responsible for serrated flow behaviour. Black-Right-Pointing-Pointer M{sub 6}C, M{sub 23}C{sub 6} and {sigma}-phase were observed at higher temperatures. - Abstract: Serrated flow behaviour of Hastelloy X has been examined over a wide range of temperature (300-1023 K) and strain rate (3 Multiplication-Sign 10{sup -3}s{sup -1} to 3 Multiplication-Sign 10{sup -5}s{sup -1}). The alloy exhibited different types of tensile serrated flow in the intermediate temperature range of 473-923 K. Normal portevin-Le Chatelier effect (PLE) exhibiting type A and B serrations were observed at temperatures less than 823 K and inverse PLE exhibiting type C serrations was noticed at temperatures above 823 K. The average activation energy value of 106 kJ mol{sup -1} for the A and B types of serrated flow has been evaluated. The evaluated activation energy value revealed that the migration of molybdenum in the nickel matrix has been found to be responsible for the occurrence of serrated flow in the alloy.

Sakthivel, T., E-mail: tsakthivel@igcar.gov.in [Mechanical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603 102 (India); Laha, K.; Nandagopal, M.; Chandravathi, K.S.; Parameswaran, P.; Panneer Selvi, S.; Mathew, M.D. [Mechanical Metallurgy Division, Indira Gandhi Centre for Atomic Research, Kalpakkam - 603 102 (India); Mannan, Sarwan K. [Special Metals Corporation, Huntington, WV 25705 (United States)

2012-02-01

199

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.)

1979-01-01

200

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

International Nuclear Information System (INIS)

Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 850 and 950"0C for 3000 h. Optical microscopy, scanning electron microscopy (SEM), electron microprobe profiles and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon phase (Ni_3Al). This diffusion was the primary cause of porosity formation at the aluminide-alloy interface. Aluminide coatings with chromium (HI-15) showed the lowest coating-substrate interface porosity and intermetallic phase growth. The presence of excess chromium in the HI-15-aluminide-coated Hastelloy X sample is believed to have compensated partially for the nickel loss by its diffusion into the nickel-depleted coating-substrate transition zone. None of the other coating additions had an obvious effect on the overall behavior of aluminide-coated Hastelloy X or Inconel 617 in the impure helium environment. The exterior of the aluminide coatings was not visually affected by the impure helium. Carbide precipitation below the coating-substrate interface, resulting from carbon ingress from the helium environment, was observed in uncoated control samples. Carburization of aluminide-coated substrates was less extensive than that of uncoated materials and was related to the degree of porosity at the coating-alloy interface. (Auth.)

1982-09-03

 
 
 
 
201

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

International Nuclear Information System (INIS)

Oxidation behavior of several heats of modified Hastelloy alloy X, named Hastelloy XR, with different Si contents was examined in isothermal, thermal cycling exposure tests. The test environment was flowing helium at 1000"0C containing controlled amounts of impurities simulating the Very High Temperature gas-cooled Reactor (VHTR) coolant. Tests were made to determine an optimization rang of Si content for obtaining higher resistance to the oxidation and less oxide spallation in the service environment. Up to 1% content, increase of the Si caused decrease of the oxidation rate, while the oxide spallation in thermal cycling was a minimum in the range of about 0.2 to 0.4% Si. These two could be explained in formation and morphology of the SiO_2 phase in the oxide and metal interface by metallographic observation and analysis. (author)

1980-01-01

202

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)

1994-01-01

203

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)

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.

Bellanger, G.

1994-03-01

204

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

2005-03-22

205

Performance of heat resistant steel castings as pallet sidewalls in an iron ore pellet induration plant  

International Nuclear Information System (INIS)

Pallet sidewall castings in five different heat resistant alloys were field tested in Iron Ore Company of Canada's iron ore pellet induration plant. Performance of four new alloys, HL, HP, HU, and Haynes Alloy A230, were compared with the traditional HH alloy after a period of 24 months in service. First, the alloys were ranked visually from best to worst. The 'new' alloys were considerably better than the HH alloy. Alloys having high chromium (HL, HP), with the exception of HH, seemed to perform the best. Surprisingly, alloys high in nickel content (HU, A230) did not fair as well. Later, metallographic examination revealed extensive micro-void formation in the interior of the heat affected areas of HH, HL and HP. The tendency for micro-void formation decreased with increasing nickel content in HU and A230. The progression of internal unsoundness in HL and HP could lead to their catastrophic failure during service. In summary, chromium imparted resistance to surface degradation, while nickel imparted resistance to internal micro-void formation. (author)

1999-08-22

206

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.

2010-06-25

207

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-06-25

208

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2010-07-01

209

ISOLATION OF HEAT RESISTANT FUNGI FROM CANNED FRUITS  

Directory of Open Access Journals (Sweden)

Full Text Available -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 processed.

Sani Ibrahim

2014-05-01

210

Hemispherical total emissivity of Hastelloy N with different surface conditions  

Energy Technology Data Exchange (ETDEWEB)

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

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

2012-07-15

211

Hemispherical total emissivity of Hastelloy N with different surface conditions  

International Nuclear Information System (INIS)

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

2012-07-01

212

Corrosion of Thermal Spray Hastelloy C-22 Coatings in Dilute HCI  

Energy Technology Data Exchange (ETDEWEB)

The microstructure and corrosion behavior of Hastelloy C-22 coatings produced using the high velocity oxygen fuel (HVOF) method have been determined and related to in-flight measurements of the particle velocity and temperature. Average particle temperatures ranged from 1280-1450 °C and velocities ranged from 565-640 ms-1. All of the coatings were greater than 98% of theoretical density and exhibited passivating behavior in 0.1 M HCl during cyclic potentiodynamic polarization testing. The passive current density was somewhat higher compared with wrought C-22 alloy and an active-passive peak attributed to the formation of a Cr-rich surface layer was observed. Resistance to corrosion and deposition efficiency improved as the particle temperature decreased. There was little effect of particle velocity on the corrosion behavior over the range of deposition conditions examined. Our results suggest that feedback control based on measurement of the particle temperature can be used to process coatings with optimum properties.

Lister, Tedd Edward; Wright, Richard Neil; Pinhero, Patrick Joseph; Swank, William David

2002-12-01

213

Metallurgical and environmental factors influencing creep behaviour of hastelloy-X  

International Nuclear Information System (INIS)

Creep and rupture behaviours of Hastelloy-X and its modified version were examined with special reference to the effect of different test environments; i.e. air, high vacuum and the simulated HTR helium coolant. The respective environments showed different effects. The vacuum environment of about 10"-"8 torr. gave best reproducible behaviour with essentially no surface-to-volume ratio effect. Such size effect was significant in the other two environments. The simulated HTR environment was characterized in its potentiality of both oxidizing selected alloy constituents and carburization. The observed behaviour was attributed to the depletion of strengthning solute elements caused by the surface reactions and the associated solid state reactions. (author)

1979-01-01

214

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

International Nuclear Information System (INIS)

Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 850"0 and 950"0C for 3000 h. Optical and scanning electron (SEM) microscopy, electron microprobe profiles, and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon-phase (Ni_3Al). This diffusion was the primary cause of porosity formation at the aluminide/alloy interface

1982-04-09

215

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

Energy Technology Data Exchange (ETDEWEB)

Commercially prepared aluminide coatings on Hastelloy X and Inconel 617 substrates were exposed to controlled-impurity helium at 850/sup 0/ and 950/sup 0/C for 3000 h. Optical and scanning electron (SEM) microscopy, electron microprobe profiles, and SEM X-ray mapping were used to evaluate and compare exposed and unexposed control samples. Four coatings were evaluated: aluminide, aluminide with platinum, aluminide with chromium, and aluminide with rhodium. With extended time at elevated temperature, nickel diffused into the aluminide coatings to form epsilon-phase (Ni/sub 3/Al). This diffusion was the primary cause of porosity formation at the aluminide/alloy interface.

Chin, J.; Johnson, W. R.; Chen, K.

1982-03-01

216

Martensitic transformation and ordering in heat-resistant Ni-Co-Cr-AI ?/? eutectics  

Science.gov (United States)

The method of thin-foil transmission electron microscopy was used to examine phase transformations in the ?-phase, representing the main heat-resistant component, of ?/? eutectics of the Ni-Co-Cr-Al system (mass % : 0 15 Co, 14 20 Cr, 8.5 10.5 Al). The martensitic transformation ?(B2)to L10 took place in all the alloys, except those with 20 mass % Cr, when they were quenched in water from 1200°C. It was found for the first time that high-rank superstructures A2B (Ni2Al) and A5B3 (Ni5Al3) could be formed in a complex-alloyed ? solid solution. Phase transformations L1{0}toA_5B_3, L1_0to 14M, L1_0to B2to A_2B, and L1_0to B2to A_5B_3 were observed in the ?-component of the eutectics when isothennal annealing temperature was increased from 250 to 600°C. At a temperature of 400°C and higher those transformations were accompanied by the decomposition of the ? solid solution and the appearance of dispersed ?-Cr particles. Structural features of the aforementioned phase transformations in heat-resistant quaternary eutectics were considered.

Kositsyn, S. V.; Katayeva, N. V.; Kositsyna, I. I.; Valiullin, A. I.; Litvinov, V. S.

2003-10-01

217

Thermal response of heat-resistant layer with pyrolysis  

Directory of Open Access Journals (Sweden)

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

Huang Haiming

2012-01-01

218

Chemical composition and heat resistance of some aerobic bacterial spores.  

Science.gov (United States)

Walker, Homer W. (Iowa State University of Science and Technology, Ames), Jack R. Matches, and John C. Ayres. Chemical composition and heat resistance of some aerobic bacterial spores. J. Bacteriol. 82:960-966. 1961.-Analyses of spores of Bacillus species for nitrogen, carbohydrate, dipicolinic acid, and phosphorus showed little correlation with heat resistance. However, as the molar concentration of magnesium increased in relation to dipicolinic acid and calcium concentrations, heat resistance generally decreased. Analyses of several batches of spores indicated that this relationship between calcium, magnesium, and dipicolinic acid did not always hold true. Therefore, while these materials apparently play an important role, other factors need to be included before a full explanation of thermal stability of spores can be made. PMID:14004586

WALKER, H W; MATCHES, J R; AYRES, J C

1961-12-01

219

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)

2000-03-01

220

Creep properties of Hastelloy X in a carburizing helium environment  

International Nuclear Information System (INIS)

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

1982-06-02

 
 
 
 
221

Humidity affects genetic architecture of heat resistance in Drosophila melanogaster  

DEFF Research Database (Denmark)

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.

Bubliy, Oleg A; Kristensen, Torsten Nygård

2012-01-01

222

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

1984-03-01

223

Heat resistance insulation for NPP pipelines and components  

International Nuclear Information System (INIS)

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

1986-01-01

224

Study of boron-content effects on weldabilities and high temperature strengths of Hastelloy-XR  

International Nuclear Information System (INIS)

The creep strength of Hastelloy-XR welded joints must be increased for VHTR (Very High Temperature Gas-Cooled Reactor). Boron, a residual element of Hastelloy-XR, was found to increase its creep strength. The effect of the Boron content on weldability and the high-temperature strength of Hastelloy-XR was researched within the range of Hastelloy-XR specifications. The high-temperature strength increases as the Boron content increases, while the weldability becomes poor. It is conclud that a Boron content of 50 ppm is the best compromise of weldability and high-temperature strength. (author)

1986-01-01

225

Effect of Si on decarburization and carburization of heat-resisting austenitic steels in an impure helium  

International Nuclear Information System (INIS)

The influence of Si on the decarburization and carburization of heat-resisting austenitic alloys were investigated in the temperature range from 800 to 1000"0C in an impure helium atmosphere. This atmosphere simulates the primaly coolant of high temperature gas cooled reacter. The results were as follows. The alloys with 0.5 -- 0.6 wt % Si were heavily carburized or decarburized above 900"0C depending on the temperatures tested, while the carburization and decarburization of the alloy with 3.4 wt % Si were negligible small in the tested temperature range. In the alloy with high Si content, the carburization or decarburization was suppressed, because a thin SiO_2 film, having a strong corrosion-resistant properties, might be formed beneath the surface-layer of (Mn, Cr) oxide. However, the films defoliate the surface oxide layers on cooling. (author)

1985-01-01

226

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

Directory of Open Access Journals (Sweden)

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.??????????? ???????? ?????????? ?????????????? ???????? ?????????? ????????? ?????? ???????????? ??????????? ?? ??????????? ?????????? ??????????. ????????? ???????????? ??????? ???????? ? ????????????, ????????? ????????????? ??????????? ????????????? ? ??????? ???????? ?????????? ???????????? ??? ???? ??????????. ???????? ??????????? ????????, ?????????????? ??????? ? ???? ????, ??? ? ???????? ????????.

Akulova Mariya Vladimirovna

2013-02-01

227

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

Energy Technology Data Exchange (ETDEWEB)

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 {mu}-phase was observed in the MZ after a tempering treatment at 950 deg. C.

Ahmad, M. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)]. E-mail: maqomer@yahoo.com; Akhter, J.I. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Akhtar, M. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Iqbal, M. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Ahmed, E. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Choudhry, M.A. [Department of Physics, Islamia University, Bahawalpur (Pakistan)

2005-03-22

228

Low cycle fatigue behavior of new heat-resistant steel HCM2S at high temperature  

Energy Technology Data Exchange (ETDEWEB)

Low cycle fatigue behavior of new low alloy, heat-resistant steel HCM2S (2.25Cr-1.6W-V-Nb-B-N) at high temperature has been investigated. The cyclic stress response curve of HCM2S exhibits rapid initial cyclic softening followed by gradual softening until macroscopic crack growth occurs. The initial softening of HCM2S steel is due to the recovery of martensite laths in carbon-rich austenitic islands, the formation of stable dislocation cells and M{sub 6}C particles. Fatigue life equation of HCM2S as a function of strain range at 580 C is also given in this paper.

Zhu Lihui; Zhao Qinxin; Gu Haicheng; Lu Yansun

1999-07-01

229

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-10-15

230

Carbide coagulation and its effect on heat resistance of ferritic steels  

International Nuclear Information System (INIS)

Investigation of the effect of carbide dispersion in low-alloyed Cr-Mo-V steels steels on their heat resistance has been carried out. Carbide coarsening rate was evaluated within the 550-700 deg C temperature range regarding particles as spherical, and additional precipitation of carbide phases does not occur in the process of creep tests. It has been established that under high-temperature creep carbide precipitates coarsening takes place along with an increase in distances between them and, hence, along with a decrease of a number of strengthening particles. Therefore, heat treatment resulting in generation of fine-dispersion carbide phase is applied to provide stable structure and properties of steels at high temperatures

1985-01-01

231

High temperature protective silicide coatings for titanium-niobium alloys  

International Nuclear Information System (INIS)

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

1985-01-01

232

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 (538"0C) 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 538"0C and lower at 649"0C for a frequency of 1 Hz

1979-01-01

233

High-Temperature Low-Cycle Fatigue Property of Heat-Resistant Ductile-Cast Irons  

Science.gov (United States)

This study examined the high-temperature degradation behavior of two types of heat-resistant Si-Mo ductile cast iron (Fe-3.4C-3.7Si-0.4Mo and Fe-3.1C-4.5Si-1.0Mo) with particular attention paid to the mechanical properties and overall oxidation resistance. Tension and low-cycle fatigue properties were examined at 600 °C and 800 °C. The mechanical tests and metallographic and fractographic analyses showed that cast iron containing higher Si and Mo contents had a higher tensile strength and longer fatigue life at both temperatures than cast iron with lower levels due to the phase transformations of pearlite and carbide. The Coffin-Manson type equation was used to assess the fatigue mechanism suggesting that the higher Si-Mo alloy was stronger but less ductile than the lower Si-Mo alloy at 600 °C. However, similar properties for both alloys were observed at 800 °C because of softening and oxidation effects. Analysis of the isothermal oxidation behavior at those temperatures showed that mixed Fe2SiO4 layers were formed and the resulting scaling kinetics was much faster for low Si-Mo containing iron. With increasing temperature, subsurface degradation such as decarburization, voids, and cracks played a significant role in the overall oxidation resistance.

Kim, Yoon-Jun; Jang, Ho; Oh, Yong-Jun

2009-09-01

234

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)

1993-11-26

235

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

International Nuclear Information System (INIS)

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

1998-01-01

236

Determination of J-integral R-curves for Hastelloy X and Inconel 617 up to 1223 K using the potential drop technique  

International Nuclear Information System (INIS)

ror Hastelloy X (T = 308 K and T = 1223 K) and for Inconel 617 (T = 308 K, 473 K, 673 K, 873 K, 973 K, 998 K, 1023 K, 1048 K, 1073 K, 1173 K, and 1223 K) the J-integral R-curves have been determined. For Hastelloy X at 308 K the multispecimen technique has been compared with the single specimen method using the potential drop technique. At 1223 K Hastelloy X delivered a low J_0-integral value. Inconel 617 showed a smooth increase in J_0 with increasing temperature, up to 998 K; above this temperature ven for large loadline displacements only blunting behaviour has been observed. The same tendency has been found for the evaluation of the tearing modulus. With increasing temperature the tearing modulus increases. In the temperature range from 998 to 1223 K the tearing modulus increases by about one order of magnitude. For both alloys the onset of stable crack growth in most cases is earlier than the load maximum is reached in the load versus load-line displacement curves. (orig.)

1982-01-01

237

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

Science.gov (United States)

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

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

1993-01-01

238

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

239

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.

2011-05-15

240

Changes in the mechanical properties of Hastelloy X when exposed to a typical gas-cooled reactor environment  

Energy Technology Data Exchange (ETDEWEB)

The helium used in a gas-cooled reactor will contain small amounts of H/sub 2/, CO, CH/sub 4/, H/sub 2/O, and N/sub 2/ which can lead to oxidation and carburization/decarburization of structural materials. Long-term creep tests were run on Hastelloy X to 30,000 h at 649 to 871/sup 0/C. It was found that extensive carburization occurred, the minimum creep rate and time to rupture were equal in air and impure helium environments, and the fracture strain was less in helium than in air. Thermal exposure in the temperature range of 538 to 871/sup 0/C resulted in the reduction of ductility in impact and tensile tests at ambient temperature, and this reduction was greater when the exposure was in impure helium rather than in air. A modified alloy with lower chromium and 2% titanium resisted carburization.

McCoy, H.E. Jr.

1981-01-01

 
 
 
 
241

Changes in the mechanical properties of Hastelloy X when exposed to a typical gas-cooled reactor environment  

International Nuclear Information System (INIS)

The helium used in a gas-cooled reactor will contain small amounts of H_2, CO, CH_4, H_2O, and N_2 which can lead to oxidation and carburization/decarburization of structural materials. Long-term creep tests were run on Hastelloy X to 30,000 h at 649 to 871"0C. It was found that extensive carburization occurred, the minimum creep rate and time to rupture were equal in air and impure helium environments, and the fracture strain was less in helium than in air. Thermal exposure in the temperature range of 538 to 871"0C resulted in the reduction of ductility in impact and tensile tests at ambient temperature, and this reduction was greater when the exposure was in impure helium rather than in air. A modified alloy with lower chromium and 2% titanium resisted carburization

1981-09-23

242

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)

1983-01-01

243

Oxidation peculiarities of chromium-nickel alloys for cladding with boron and silicon in water high-temperature-high-pressure steam  

International Nuclear Information System (INIS)

Studied is the heat resistance of chromium-nickel alloys containing boron and silicon in water high-temperature-high-ressure steam, determined is the composition of corrosion products. It is found that volatility of boron anhydrite promotes the loosening of oxide film and is the main cause of the decreased heat resistance of these alloys. Heat resistance may be increased by changing chemical and phase composition of the alloy, due to the suppression of nickel borides formation in particular

1980-06-01

244

Characteristics of heat resistance of metal of certain grade  

International Nuclear Information System (INIS)

Modern development of power machine construction is accompanied by continuous increase of operation parameters and service time of power machine elements. Under the conditions heat resistance characteristics, evaluated by extrapolation for the calculated service time on the basis of restricted duration tests play the decisive role. Pipeline systems (steam supply lines and steam superheaters) are the most metal-consuming elements of modern thermal power plants. Results of the tests are generalized, their statistical processing using the M 220 and ES computers, is realized. According to the method suggested parameters of long-term strength equations for commercial steels are given. Pearlitic, aystenitic and high-chromium steels were considered. 30 comercial series of 12Kh1MF steel were tested by various organizations and the results were processed. Total number of tested samples exceeded 700

1988-01-01

245

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

International Nuclear Information System (INIS)

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

2007-01-01

246

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

Directory of Open Access Journals (Sweden)

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

Takahide Fukuyama

2011-09-01

247

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

International Nuclear Information System (INIS)

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

1995-01-01

248

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)

2011-05-01

249

Heat Resistance of Native and Demineralized Spores of Bacillus subtilis Sporulated at Different Temperatures  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Demineralization reduced heat resistance of B. subtilis spores, but the pattern and magnitude of the reduction depended on sporulation temperature and on heating menstruum pH. The differences in heat resistance of native spores caused by sporulation temperature almost disappeared after demineralization. Demineralized spores were still susceptible to the heat-sensitizing effect of acidic pH.

Palop, Alfredo; Sala, Francisco J.; Condo?n, Santiago

1999-01-01

250

Effect of W on creep properties of martensitic heat resistant HT9M steels  

International Nuclear Information System (INIS)

Effect of W on creep properties of martensitic heat resistant HT9M steel have been investigated at 600 and 650 deg C. The creep rupture strength of W added HT9M steel was higher than that of HT9M steel. The addition of W decreased the self-diffusion rate of iron atom and delayed the microstructural degradation during creep. As seen in dispersion-strengthened alloys high stress exponent, n, and activation energy, Qc, are found in these steels. During creep deformation, formation of subgrain, growth and agglomeration of precipitates and precipitation of Laves phase occurred. These microstructural changes made the steels soften. When the stress was applied, hardness values were abruptly decreased at an early stage and remained constant with time. The degree of softening of W added HT9M steel was less than that of HT9M. But when the stress was not applied, the decrease of hardness value was not occurred in both steels. (author)

2000-09-01

251

Study on internal pressure creep strength of Hastelloy X cylindrical specimen containing an axial surface notch  

International Nuclear Information System (INIS)

Creep tests of Hastelloy X alloy have been performed at 900 deg C under internal pressure, using cylindrical specimens with an artificial defect. The purpose of this research is to investigate the effect of defect size on the creep strength. Two kinds of cylindrical specimens were used. One was 62 mm in outer diameter, 3.0 mm in thickness and 240 mm in length. Another was 66 mm in outer diameter, 6.0 mm in thickness and 240 mm in length. Axial notches were machined on the outer surface of these specimens by a milling cutting. Diametral deformation of the specimen was measured during the test by dial gauges mounted on quartz rods. Creep crack growth depth was measured using the electrical potential method. The numerical analysis using a finite element program ADINA has been performed to investigate the creep deformation around the artificial defect. Analytical model represents one-half of the cylindrical specimen which is 56.0 mm in inner diameter and 3.0 mm in thickness, and has the axial notch of 1.0 mm in depth with infinite length. Elastic-plastic and creep analysis of this model was carried out by incremental method of the time step of 0.01 hours. The following results are concluded from these tests and analyses. [1] The creep rupture time decreases with increasing notch length. [2] The electric potential method is very useful for measuring the creep crack growth depth. [3] The initial creep deformation around the notch is obtained from the finite element analysis. (author)

1986-01-01

252

Studies Concerning Heat-Resisting Additives for Bitumens  

Directory of Open Access Journals (Sweden)

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.

Livia Groll

2008-01-01

253

Change of heat resistance on spore forming bacteria after irradiation  

International Nuclear Information System (INIS)

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

2001-09-01

254

Change of heat resistance on spore forming bacteria after irradiation  

Energy Technology Data Exchange (ETDEWEB)

The effect of heat resistance of endospores after gamma-irradiation were investigated for application to decontaminate microorganisms in spices or other dried food materials. D{sub 10} values of endospores dried on glass fiber filter with additives of 2% peptone + 1% glycerin were obtained to be 1.8 kGy for Bacillus pumilus, 1.1 kGy for B. cereus, 2.2 kGy for Clostridium botulinum Type A and 2.4 kGy for Cl. botulinum Type E, respectively. Non-irradiated endospores of B. pumilus and B. cereus were inactivated with 40 min of heat treatment at 100degC in water. When endospores were irradiated with 5 kGy, these bacteria were inactivated below 20 min of heating at 100degC in water. In the case of Cl. botulinum Type A and Type E, non-irradiated endospores were inactivated with 30 min of heat treatment at 100degC in water, and irradiated endospores at 5 kGy were inactivated below 15 min of heating. However, all of these bacteria could not inactivate endospores even after heating more than 2 hours at 100degC in dry condition or 80degC in water, and decreased a little of necessary times for inactivation of heat treatment after irradiation at 5 kGy. (author)

Ito, Hitoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

2001-09-01

255

A new class of bio-heat resisted polymer blend.  

Science.gov (United States)

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.

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

2009-03-01

256

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)

1996-01-01

257

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.)

1975-06-08

258

Heat resistance of Salmonella in various egg products.  

Science.gov (United States)

The heat-resistance characteristics of Salmonella typhimurium Tm-1, a reference strain in the stationary phase of growth, were determined at several temperatures in the major types of products produced by the egg industry. The time required to kill 90% of the population (D value) at a given temperature in specific egg products was as follows: at 60 C (140 F), D = 0.27 min for whole egg; D = 0.60 min for whole egg plus 10% sucrose; D = 1.0 min for fortified whole egg; D = 0.20 min for egg white (pH 7.3), stabilized with aluminum; D = 0.40 min for egg yolk; D = 4.0 min for egg yolk plus 10% sucrose; D = 5.1 min for egg yolk plus 10% NaCl; D = 1.0 min for scrambled egg mix; at 55 C (131 F), D = 0.55 min for egg white (pH 9.2); D = 1.2 min for egg white (pH 9.2) plus 10% sucrose. The average Z value (number of degrees, either centigrade or fahrenheit, for a thermal destruction time curve to traverse one logarithmic cycle) was 4.6 C (8.3 F) with a range from 4.2 to 5.3 C. Supplementation with 10% sucrose appeared to have a severalfold greater effect on the heat stabilization of egg white proteins than on S. typhimurium Tm-1. This information should be of value in the formulation of heat treatments to insure that all egg products be free of viable salmonellae. PMID:4890741

Garibaldi, J A; Straka, R P; Ijichi, K

1969-04-01

259

Compatibility of Hastelloy XR with boron-carbide and graphite mixture  

International Nuclear Information System (INIS)

To use a Hastelloy XR for VHTR nuclear fuel cladding, the compatibility with a sintered boron-carbide and graphite mixture as neutron absorber was investigated. A metallographic study on metal which was heated at 700-10500C for 100-500 hours in He atmosphere was carried out. When the specimens are heated above 10000C, boron and carbon diffused easily into the metal and produced molybdenum borides and chromium carbides in the diffusion layer. Below 8500C, Hastelloy XR did not react with the mixture elements. It is recognized that the diffusion of boron and carbon into the metal was delayed if molybdenum insertion or ceramic coating has been applied, even though the specimen was heated above 10000C. Tensile test at high temperature (850-10500C) shows that the elongation is decreased with the increasing of the thickness of diffusion layer of boron and carbon in Hastelloy XR. (author)

1985-01-01

260

Surface modification of Hastelloy C-276 by SiC addition and electron beam melting  

International Nuclear Information System (INIS)

Electron beam surface melting of Hastelloy C-276 with the SiC addition is carried out to improve the surface properties. The resulted microstructure and non-equilibrium phases are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive system (EDS). The Hastelloy C-276 is successfully surface-hardened by electron beam melting, the surface hardening effect can be attributed to both microstructure refinement and eutectic phases produced by EB. During EB melting the SiC broke into small pieces and spread in the microstructure increasing the surface hardness by thirteen times

2005-01-01

 
 
 
 
261

Surface modification of Hastelloy C-276 by SiC addition and electron beam melting  

Energy Technology Data Exchange (ETDEWEB)

Electron beam surface melting of Hastelloy C-276 with the SiC addition is carried out to improve the surface properties. The resulted microstructure and non-equilibrium phases are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive system (EDS). The Hastelloy C-276 is successfully surface-hardened by electron beam melting, the surface hardening effect can be attributed to both microstructure refinement and eutectic phases produced by EB. During EB melting the SiC broke into small pieces and spread in the microstructure increasing the surface hardness by thirteen times.

Ahmad, M. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Akhter, J.I. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)]. E-mail: jiakhter@yahoo.com; Iqbal, M. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Akhtar, M. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Ahmed, E. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Shaikh, M.A. [Physics Research Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan); Saeed, K. [Nuclear Materials Division, Pakistan Institute of Nuclear Science and Technology, P.O. Nilore, Islamabad (Pakistan)

2005-01-01

262

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.)

1983-04-01

263

Carbide strengthening of wrought nickel-base alloys  

Energy Technology Data Exchange (ETDEWEB)

Various metallurgical methods exist for increasing the creep rupture strength of high-temperature alloys. This article specifically describes the possibilities of carbide strengthening, as increasing the heat resistance and creep rupture strength by means of precipitated carbides opens up several possibilities for new types of alloys. Increasing heat resistance and creep rupture strength by carbide strengthening is of great importance, especially with regard to heat-resistant austenitic stainless steels, as solid solution hardening of iron by means of elements such as, for example, molybdenum, tungsten, and tantalum is only possible to a limited extent due to their restricted solubility. (orig.)

Brill, U. [Krupp VDM GmbH, Altena (Germany)

2001-11-01

264

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

International Nuclear Information System (INIS)

Highlights: ? Hastelloy C22 coatings were prepared by diode laser cladding technique. ? Higher laser speed resulted in smaller grain size. ? Size-effect played the key role in the hardness measurements by different ways. ? Coating with higher laser scanning speed displayed higher nano-scratch resistance. ? Small grain size was beneficial for improvement of coating corrosion resistance. -- Abstract: The Hastelloy C22 coatings H1 and H2 were prepared by laser cladding technique with laser scanning speeds of 6 and 12 mm/s, respectively. Their microstructures, mechanical properties and corrosion resistance were investigated. The microstructures and phase compositions were studied by metallurgical microscope, scanning electron microscope and X-ray diffraction analysis. The hardness and scratch resistance were measured by micro-hardness and nanoindentation tests. The polarization curves and electrochemical impedance spectroscopy were tested by electrochemical workstation. Planar, cellular and dendritic solidifications were observed in the coating cross-sections. The coatings metallurgically well-bonded with the substrate are mainly composed of primary phase ?-nickel with solution of Fe, W, Cr and grain boundary precipitate of Mo6Ni6C. The hardness and corrosion resistance of steel substrate are significantly improved by laser cladding Hastelloy C22 coating. Coating H2 shows higher micro-hardness than that of H1 by 34% and it also exhibits better corrosion resistance. The results indicate that the increase of laser scanning speed improves the microstuctures, mechanical properties and corrosion resistance of Hastelloy C22 coating

2013-03-15

265

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2013-03-15

266

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 machining.

2011-02-01

267

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

Science.gov (United States)

Clothing heat and vapour resistance are important inputs for standards and models dealing with thermal comfort, heat- and cold-stress. A vast database of static clothing heat resistance values is available, and this was recently expanded with correction equations to account for effects of movement and wind on the static value of heat resistance in order to obtain the dynamic heat resistance of clothing ensembles. For clothing vapour resistance, few data were available so far. Indices for vapour permeability (im) and reduction factors for vapour transfer (Fpcl) of clothing were used instead, using a relation between heat and vapour resistance to derive the clothing vapour resistance from the value for clothing heat resistance. This paper reviews the two commonly used approaches (im and Fpcl), as well as five alternative approaches to the problem. The different approaches were evaluated for their accuracy and their usability. The present paper shows that the currently used relations are not adequate when the wearer of the clothing starts moving, or is exposed to wind. Alternative approaches are shown to improve the determination of dynamic clothing vapour resistance, though some are thought to be too complex. An empirical description of the relation between the clothing permeability index (im) and the changes in clothing heat resistance due to wind and movement was selected as the most promising method for deriving clothing vapour resistance. For this method the user needs to know the static heat resistance, the static im value of the clothing and the wind- and movement-speed of the wearer. This method results in a predicted maximal decrease in clothing vapour resistance by 78%, when clothing heat resistance is reduced by 50%, which is consistent with theoretical expectations and available data. PMID:10481633

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

1999-07-01

268

Swelling in Neutron Irradiated Nickel-Base Alloys.  

Science.gov (United States)

Inconel 625, Incoloy 800 and Hastelloy X were neutron irradiated at 500 to 700 exp 0 C. 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 th...

H. R. Brager W. L. Bell

1972-01-01

269

The use of aluminium-enriched layers on Hastelloy X against high temperature carburization in high temperature gas-cooled reactor helium  

International Nuclear Information System (INIS)

The possibility of protecting nickel-based alloys against carburization using Ni-Al layers is discussed. Ni-Al layers were produced using the chemical vapour deposition reaction: AlCl3+(3/2)H2+Ni-based alloy ? Ni-Al+3HCl. The kinetics of growth of an Ni-Al layer on nickel and the nickel-based alloys Hastelloy X, IN-738LC and IN-617 in the temperature range 1173-1373 K at total pressures ranging from 100 to 800 mbar are described. No carbon uptake occurs in the layer or in the bulk alloy, because of the formation of an ?-Al2O3 oxide layer in CH4-H2 gas mixtures with carbon activities from 0.2 to 0.8 and at temperatures of up to 1273 K. Al2O3 formation is caused by the presence of oxygen as an impurity in the CH4-H2 gas mixtures. (Auth.)

1983-09-30

270

Heat shock protein levels are not elevated in heat-resistant B16 melanoma cells.  

Science.gov (United States)

Heat-resistant variants have been selected from B16 melanoma cells and from surface mutants previously derived from them. The aim of the present study was to explore the possible role of heat shock proteins in the manifestation of this heat resistance. The major heat shock proteins evident after heating have subunit molecular weights of 68, 70, 89, and 110K on sodium dodecyl sulfate-polyacrylamide gels. The 68-kDa protein is not evident in any of the unheated B16 cell lines while the levels of the other heat shock proteins are elevated after heating. The constitutive levels of the 70, 89, and 110-kDa heat shock proteins were assessed after gel electrophoretic separation of proteins in several of the heat-resistant variants. No major differences were found in the levels of these proteins between the heat-sensitive parent lines and the heat-resistant variants. We therefore conclude that heat shock proteins are not a determining factor in the heat-resistant phenotype of B16 melanoma cells. PMID:3952273

Anderson, R L; Tao, T W; Betten, D A; Hahn, G M

1986-02-01

271

Oxidation kinetics and oxidation mechanism in tungsten-vanadium alloys  

International Nuclear Information System (INIS)

The method of continuous weighing has been used to investigate oxidation of tungsten alloys with 1-20 weight% V at 900-1300 deg C in the air. It is shown that oxidability of alloys containing 1% V noticeably decreases as compared with tungsten. Alloys with 1-10% V have higher heat resistance as compared with tungsten but positive effect of vanadium decreases with an increase of alloying degree and at 20% vanadium content the alloying effect completely disappears

1982-01-01

272

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

International Nuclear Information System (INIS)

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

2005-01-01

273

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)

2008-07-01

274

Heat resistant/radiation resistant cable and incore structure test device for FBR type reactor  

International Nuclear Information System (INIS)

A heat resistant/radiation resistant coaxial cable of the present invention comprises an insulation layer, an outer conductor and a protection cover in this order on an inner conductor, in which the insulation layer comprises thermoplastic polyimide. In the same manner, a heat resistant/radiation resistant power cable has an insulation layer comprising thermoplastic polyimide on a conductor, and is provided with a protection cover comprising braid of alamide fibers at the outer circumference of the insulation layer. An incore structure test device for an FBR type reactor comprises the heat resistant/radiation resistant coaxial cable and/or the power cable. The thermoplastic polyimide can be extrusion molded, and has excellent radiation resistant by the extrusion, as well as has high dielectric withstand voltage, good flexibility and electric characteristics at high temperature. The incore structure test device for the FBR type reactor of the present invention comprising such a cable has excellent reliability and durability. (T.M.)

1993-11-04

275

Effect of oxidation medium on the properties of titanium alloys  

International Nuclear Information System (INIS)

Results of investigation into oxidation of titanium and its alloys with aluminium, tungsten, tin, germanium, silicon and nickel in the air at 600-1000 deg C are presented. It is shown that titanium alloyage with aluminium, silicon, nickel, tungsten increases its heat resistance, while alloyage with germanium and tin reduces heat resistance. Heat resistance of the investigated titanium alloys is determined by the composition and structure of scale and subscale layers, effect of the composition ad structure of subscale layers in some cases being determinative (alloys with tin, nickel and germanium). Formation in subscale layers of intermetallide zones or even interlayers comprisng only the alloying element will inevitably affect physicochemical characteristics of alloys

1986-01-01

276

Comparison of Pressure Resistances of Spores of Six Bacillus Strains with Their Heat Resistances  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The pressure resistances of the spores of six Bacillus strains were examined at 5 to 10(deg)C and were compared with their heat resistances. The pressure treatments (at 981 MPa for 40 min and at 588 MPa for 120 min) did not inactivate the spores of B. stearothermophilus IAM12043, B. subtilis IAM12118, and B. licheniformis IAM13417. However, these spores had large differences in heat resistance. The spores of B. megaterium IAM1166 were 9.3 times more pressure resistant but 246 times less heat ...

1996-01-01

277

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

International Nuclear Information System (INIS)

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

1991-10-10

278

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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

Khidhir, Basim A.; Bashir Mohamed; Younis, Mahmoud A. A.

2010-01-01

279

Alloy  

Science.gov (United States)

The Mg98.5Gd1Zn0.5 alloy produced by a powder metallurgy route was studied and compared with the same alloy produced by extrusion of ingots. Atomized powders were cold compacted and extruded at 623 K and 673 K (350 °C and 400 °C). The microstructure of extruded materials was characterized by ?-Mg grains, and Mg3Gd and 14H-LPSO particles located at grain boundaries. Grain size decreased from 6.8 ?m in the extruded ingot, down to 1.6 ?m for powders extruded at 623 K (350 °C). Grain refinement resulted in an increase in mechanical properties at room and high temperatures. Moreover, at high temperatures the PM alloy showed superplasticity at high strain rates, with elongations to failure up to 700 pct.

Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

2014-07-01

280

Long term creep behavior of Incoloy 800H and Hastelloy X in simulated HTGR environments  

International Nuclear Information System (INIS)

Creep rupture tests on Incoloy 800H and Hastelloy X had been carried out in simulated steam-cycle HTGR helium environments for two levels of moisture. The wet helium studies have been completed for a maximum test time of 16,000 hours; the dry helium tests are still in progress with a maximum test time of 18,000 hours. Standard air tests have been running for over 35,000 hours. The creep rupture behavior of Incoloy 800H in the wet helium is not significantly different from that in air but the dry helium increases the rupture life. Hastelloy X shows a slightly lower rupture life in the wet helium while the dry helium improves the creep properties in comparison with standard air tests. Oxidation is the major gas-metal interaction in both helium environments

1982-06-02

 
 
 
 
281

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

Science.gov (United States)

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.

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

1987-07-01

282

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

1994-01-01

283

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.)

1992-01-01

284

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

Science.gov (United States)

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).

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

2011-08-23

285

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

1986-03-01

286

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

Science.gov (United States)

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).

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

2010-07-06

287

Hastelloy-X for high-temperature 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 metal and weldments under realistic service conditions. The test environment studied was helium that contained small amounts of H2, CH4, and CO. This environment was found to be 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 the same properties as base metal except for lower fracture strains under some conditions. Some samples were aged for 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 effects of aging were the significant reduction in the fracture strains at ambient temperature and the lower strains for samples aged in high-temperature gas-cooled reactor (HTGR) helium than for those aged in inert gas. Under some conditions, aging also resulted in increased yield and ultimate tensile strength. Creep tests failed to show the effects of environment, aging, or welding on the creep strength of Hastelloy-X; however, the fracture strains for weldments were generally lower than they were for base metal. Prior aging in inert gas for 20 000 h at 538 and 8710C reduced the fatigue life slightly, but no difference was observed in the fatigue properties of samples aged in air and HTGR helium environments

1984-01-01

288

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

Science.gov (United States)

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.

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

2013-03-01

289

Electrochemical Impedance Spectroscopy Of Metal Alloys  

Science.gov (United States)

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.

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

1993-01-01

290

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

Energy Technology Data Exchange (ETDEWEB)

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

NONE

1998-03-01

291

Type sichromal steel with high heat resistance under operation conditions of refractory-faced water wall screens of steam boilers  

International Nuclear Information System (INIS)

Investigation results of aluminium (1...3%) influence on the heat resistance of the O3Kh8S steel under conditions, close to operation conditions of refractory-faced water wall sereens (in the contact with carborundum packing), are presented. Reasons for decrease of the 03Kh8SYu steel heat resistance under conditions of carborundum packing influence are analysed

1981-01-01

292

Influence of cerium, zirconium and boron on the oxidation resistance of heat-resistant steels in air  

International Nuclear Information System (INIS)

Isothermal and cyclic oxidation experiments were carried out in air to investigate the influence of the minor elements such as Cerium, Zirkonium and Boron on the oxidation resistance of heat resistant ferritic and austenitic steels like X10Cr18, X10CrAl18 and X15CrNiSi2012. In the case of cyclicexperiments samples were exposed at constant temperatures for 100 h and then cooled to R.T. This cycle was repeated 10 times. The corrosion was determined as weight change and was continuously measured by a thermo-balance. The distribution of the alloying elements on the phase boundary scale/steel was examined by Scanning-Electron-Microscope. Addition of small amounts of Ce (0.3 wt-% max.) could reduce the oxidation rate in the case of isothermal and cyclic conditions. Zirkonium concentrations below 0.1 wt-% could have a beneficial effect, but at higher concentrations the oxidation rate increases with increasing amounts of Zr. Small Boron concentrations of 0.02 wt-% lead to catastrophic oxidation at temperatures above 10000C. (orig.)

1981-01-01

293

Nylon 46 of moulding material expands heat resistant application. Tainetsu yoto wo hirogeru seikeiyo zairyo nylon 46  

Energy Technology Data Exchange (ETDEWEB)

This paper introduced Nylon 46 which has the most exellent heat resistance of nylon resins. Nylon 46 is a crystalline one which is obtained by polycondensation of tetramethylenediamine and adipic acid. Nylon 46 of moulding material has high heat distortion temperature and superior soldering resistance, shows slight reduction of rigidity at high temperature, and can resist to creep. Further, this has also superior friction resistance and wear resistance, can resist to stress cracking caused by cyclic stress and has good fatigue resistance. Nylon 46 is suitable to apply to mechanical field owing to the high chemical resistance and oil resistance. New brands from Nylon 46 are developed by inorganic filler reinforcing and alloying, of which low water absorption brand, blow moulding brand, super tough brand, and high filler brand are included. Nylon 46 for new fields is used as many kinds of part in engine room for automotive field and as electronic parts for surface mounting of electric and electronic parts. 9 figs., 11 tabs.

Yasue, K.; Matsuo, T. (Unitika, Ltd., Osaka (Japan))

1990-08-01

294

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

International Nuclear Information System (INIS)

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

1975-01-01

295

Theoretical and experimental study of multicomponent nickel alloys  

International Nuclear Information System (INIS)

Importance of heterophase character in nickel and intermetallic compound alloys is investigated. Areas of existance and mechanical properties of multicomponent #betta#- and #betta#'-phases are investigated. It is shown, that theoretical methods for evaluation of alloying element effect on the properties of nickel alloys can be used for determination their optimum (by heat resistance) compositions. Correlation between changes of phase yield limit during alloying and the values of their interatomic forces is found

1982-01-01

296

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

Energy Technology Data Exchange (ETDEWEB)

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.

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

297

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

Science.gov (United States)

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.

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

2013-09-01

298

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

Science.gov (United States)

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

Scaramuzza, Nicoletta; Berni, Elettra

2014-01-01

299

Weldability and weld performance of a special grade Hastelloy-X modified for high-temperature gas-cooled reactors  

International Nuclear Information System (INIS)

The characteristics of weld defects in the electron beam (EB) welding and the tungsten inert gas (TIG) arc welding for Hastelloy-XR, a modified version of Hastelloy-X, are clarified through the bead-on-plate test and the Trans-Varestraint test. Based on the results, weldabilities on EB and TIG weldings for Hastelloy-XR are discussed and found to be almost the same as Hastelloy-X. The creep rupture behaviors of the welded joints are evaluated by employing data on creep properties of the base and the weld metals. According to the evaluation, the creep rupture strength of the EB-welded joint may be superior to that of the TIG-welded joint. The corrosion test in helium containing certain impurities is conducted for the weld metals. There is no significant difference of such corrosion characteristics as weight gain, internal oxidation, depleted zone, and so on between the base and the weld metals. Those are superior to Hastelloy-X

1984-01-01

300

The fabrication of a process heat exchanger for a SO3 decomposer using surface-modified hastelloy X materials  

International Nuclear Information System (INIS)

This study investigates the surface modification of a Hastelloy X plate and diffusion bonding in the assembly of surface modified plates. These types of plates are involved in the key processes in the fabrication of a Process Heat Exchanger (PHE) for a SO3 decomposer. Strong adhesion of a SiC film deposited onto Hastelloy X can be achieved by a thin SiC film deposition and a subsequent N ion beam bombardment followed by an additional deposition of a thicker film that prevents the Hastelloy X surface from becoming exposed to a corrosive environment through the pores. This process not only produces higher corrosion resistance as proved by electrolytic etching but also exhibits higher endurance against thermal stress above 900 .deg. C. A process for a good bonding between Hastelloy X sheets, which is essential for a good heat exchanger, was developed by diffusion bonding. The diffusion bonding was done by mechanically clamping the sheets under a heat treatment at 900 .deg. C. When the clamping jig consisted of materials with a thermal expansion coefficient that was equal to or less than that of the Hastelloy X, sound bonding was achieved

2008-04-01

 
 
 
 
301

Time and Temperature Dependence on Flexural Strength of Heat-resistant CFRP Laminates  

Science.gov (United States)

The flexural fracture behavior of four kinds of CFRP laminates with the combination of heat-resistant thermosetting resin and PAN-based carbon fiber were investigated by three-point bending tests over a wide range of temperature and deflection rate. The flexural fracture behavior by the fractographs as well as the flexural strength strongly depend on the testing rate and temperature. The master curves for these strengths can be produced based on the time-temperature superposition principle. The time-temperature shift factor for the flexural strength of each laminates is quantitatively in good agreement with that for the stress-strain relation of the corresponding matrix resin. Therefore, it is cleared that the time and temperature dependence of flexural fracture behavior of heat-resistant CFRP laminates are mainly controlled by the viscoelastic behavior of matrix resin.

Hamagami, Yozo; Sekine, Naoyuki; Nakada, Masayuki; Miyano, Yasushi

302

[Possible pathways of heat resistance induction in plant cells by exogenous nitrogen oxide].  

Science.gov (United States)

The mechanisms of influence of exogenous nitrogen oxide (NO) on heat resistance of wheat coleoptiles have been studied. The treatment of plant cells with nitrogen oxide donor (sodium nitroprusside) resulted in the increase of superoxide anion-radical (O2*-) generation already after 10 minutes. The inhibitor of protein biosynthesis cycloheximide did not inhibit the O2*- generation by coleoptiles caused with the NO donor whereas the inhibitor of phosphatidic acid formation (butanol-1) partially inhibited it. The treatment of coleoptiles with the calcium ionophore (A23187) or activator of inositol cycle (inositol) compensated the suppression of butanol-1 effect on NO-dependent O2*- formation. Butanol-1 has also leveled the induction of coleoptiles heat resistance caused by the NO donor, whereas calcium ionophore and inositol almost completely removed the butanol-1 effect. The possible mechanisms of participation of reactive oxygen species, phosphatidic acid and calcium ions in the realization of NO physiological effects are discussed. PMID:23285747

Karpets, Iu V; Kolupaev, Iu E; Iastreb, T O; Dmitriev, A P

2012-01-01

303

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

Science.gov (United States)

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.

Ontiveros, Cordelia

1988-01-01

304

Structure and Properties of Type KhN 60 NBTYu (EP 487) Alloy (Stryaktyara i Svoistva Splava Marki KHN60 MVTYU (EP 487).  

Science.gov (United States)

The development of a new weldable, heat resistant alloy (Type EP 487) with a nickel-chromium base is discussed. The alloy possess improved mechanical properties in comparison to the currently employed EP 202 alloy. The maximum hardening of the new alloy w...

B. A. Karbonov G. F. Kosheleva L. N. Zemina V. K. Tsvetkova

1970-01-01

305

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

Science.gov (United States)

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.

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

2010-05-01

306

Experimental determination of contact heat resistance between uranium dioxide and cladding  

International Nuclear Information System (INIS)

The objective of this work was studying thermal contact resistance between fuel and cladding under different conditions similar to reactor operating conditions in order to avoid overheating that could cause damage. According to experimental data, variation of contact heat resistance was analyzed dependent on the neutron flux. Using calculated values of fuel pellets radial expansion, dependence of heat contact resistance is given as a function of gap dimensions at constant temperature

1970-06-08

307

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

Science.gov (United States)

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

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

1996-03-01

308

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 750"0C and 900"0C. 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)

1980-01-01

309

High-temperature low-cycle fatigue tests on Hastelloy X  

International Nuclear Information System (INIS)

Tensile and low cycle fatigue tests were conducted on Hastelloy X in vacuum at several temperatures from room temperature to 9000C. The mid-range ductility minimum generally observed in nickel-base superalloys did not show itself in the material containing yttrium and which was solution heat treated at a higher temperature. The fatigue crack growth rate was calculated from the measured intervals of fatigue striation observed by scanning electron microscopy. The specimen that was fractured at 9000C did not present the typical fatigue surface, and instead the rupture was characterized by marked reduction in area and a large cavity in the center of the fracture. (auth.)

1977-01-01

310

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

International Nuclear Information System (INIS)

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 1.3x103 W/m at 50 deg C, 106 degrees and 2.6x183 W/m at 170 deg C, respectively

1984-09-01

311

Creep crack growth behavior of several structural alloys  

Science.gov (United States)

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.

Sadananda, K.; Shahinian, P.

1983-07-01

312

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

The prevalence, contamination and heat resistance of Listeria monocytogenes were investigated in meat products and meat-processing plants. Moreover, trends of human listeriosis in Latvia were studied over a 10-year period from 1998 to 2007.

Berzins, Aivars

2010-01-01

313

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)

1978-01-01

314

Creep and rupture behavior of hastelloy XR in simulated HTGR helium  

International Nuclear Information System (INIS)

Creep and rupture tests were conducted on Hastelloy XR (a modified version of the conventional Hastelloy X) at 1,073, 1,173 and 1,273K in simulated high-temperature gas-cooled reactor helium. The test section of creep testing machine was designed and constructed with special care for impurity chemistry in helium. A device for counting Moire patterns was developed for contamination-free creep strain measurement. The test results up to 10,000 h showed no significant degradation in creep properties. Comparing the data on the stresses to rupture, to cause 1% total strain and to the onset of tertiary creep, the stress to cause 1% total strain is judged to be the dominant factor for the allowable stress (St) in the ASME Code. Carbon analysis for ruptured specimen showed that carburization was limited to the region near the ruptured portion and slight carbon intrusion occurred only in the early stage of exposure. Surface cracks were not responsible for creep-rupture, because they were blunted at the depth of approximately 100 ?m from the specimen surface at 1,173K and 200 ?m at 1,273K. Internally formed cracks were initiated at the sites of carbide precipitation at grain boundary, growing nearly perpendicular to the stress axis. Recrystallization observed was localized at 1,173K but became pronounced at 1,273K. Creep deformation enhanced coasening of the grain boundary carbide under tensile stress. (author)

1994-10-01

315

Investigations into forming process of subsurface layers of the titanium VT-9 alloy after electropark alloying  

International Nuclear Information System (INIS)

Investigation result of the phase composition and structure of the surface layer of the VT-9 titanium alloy after electrospark alloying with Ni, Al, NiAl are presented. It is shown that the surface layer is formed at the expense of the anode material deposition, its interaction with the cathode material and interelectrode medium. At that, the thickness of the layer detected roentgenographically exceeds the thickness of the layer detected metallographically. The obtained data of phase composition as to the depth of the alloyed layer permit to approach selectively to the material of the alloying electrode to increase heat resistance of the VT-9 titanium alloy

1980-01-01

316

Oxidation of titanium alloys. Okislenie titanovykh splavov  

Energy Technology Data Exchange (ETDEWEB)

The available experimental data on the oxidation kinetics of titanium and commercial titanium alloys (alpha and beta types) and on the phase composition of the oxide layers are summarized and generalized. The existing theories of high-temperature gas corrosion are reexamined in a critical manner; the experimental data are discussed from the standpoint of the theory of crystal chemistry. The mechanism by which the alloying elements and heat-resistant coatings affect the oxidation rate of titanium is identified. 368 references.

Lazarev, E.M.; Kornilova, Z.I.; Fedorchuk, N.M.

1985-01-01

317

Analysis of thermal fatigue properties by Barkhausen noise effect on E911 heat-resistance steel  

International Nuclear Information System (INIS)

In the present research work, it was studied whether magnetic approaches can be used for the life prediction evaluation and defect measurement in heat-resistance E911 ferritic steel. Destructive and non-destructive test methods were used. Transmission electron microscopy, coercivity measurements and Barkhausen-Noise(BN) measurements were also used. This research aims to clarify the dependency how the thermal fatigue process influences the magnetic properties of E911 steel, which are often used in european power plant applications. It is also attempted to investigate, whether the BN measurement can be applied to monitor the microstructural changes caused by thermal fatigue of the E911 ferritic steel

2005-11-01

318

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

1982-07-01

319

Microstructural evolution during creep deformation of an 11CrMoVNb ferritic heat resistant steel  

Energy Technology Data Exchange (ETDEWEB)

The effect of creep deformation on the microstructural development of an 11CrMoVNb ferritic heat resistant steel during high temperature creep test is investigated. Coarsening behavior of the precipitates, M{sub 23}C{sub 6} and MX, and growth behavior of martensite laths of crept specimens are carefully observed from both gage and grip parts of the specimens in order to discuss the effect of deformation. Particle coarsening and martensite lath widening are pronounced in the gage part due to the creep deformation. (orig.)

Lee, Kyu-Ho; Park, Dae-Bum [Korea Institute of Science and Technology, Seoul (Korea, Republic of). Materials and Devices Div.; Korea Univ., Seoul (Korea, Republic of). Dept. of Materials Science; Kwun, S.I. [Korea Univ., Seoul (Korea, Republic of). Dept. of Materials Science; Suh, Jin-Yoo; Jung, Woo-Sang [Korea Institute of Science and Technology, Seoul (Korea, Republic of). Materials and Devices Div.

2010-07-01

320

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

1981-01-01

 
 
 
 
321

Oxidation protection of austenite steels by heat-resisting glass-and-enamel coatings  

International Nuclear Information System (INIS)

The use of glass-enamel coatings for corrosion protection of austenitic steels during heat treatment has been investigated. When working out the composition of the protective coating, the method of mathematical planning of experiments has been used. It is shown that the coating under investigation can best be used in heat treatment of items with a prolonged time of heating to 1050 deg C (18-20 hr). The savings resulting from the introduction of the heat-resistant glass-enamel coating exceed 30000 roubles

1977-01-01

322

Kinetics and mechanisms of crack propagation under creep in heat resisting steel  

International Nuclear Information System (INIS)

Distribution of creep cracks is studied for rotor heat resisting steel within the temperature range of 460...560 deg C and test duration up to 3000 h. A considerable growth of cracks for 1000 h is observed with the values of stress intensity factors 3-7 times lower than the Ksub(Ic) value. Intergranular fracture is observed with comparatively high values of Ksub(I), crack growth being of a discontinuous character; with comparatively small value of Ksub(I) the crack growth occurs due to the growth of pores, their coalescence and convergence with the crack tip

1985-06-01

323

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

1980-04-01

324

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)

2010-07-13

325

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

1979-04-01

326

Fracture properties and heat resistance of ceramics consisting of microspheres of stabilized zirconium dioxide  

International Nuclear Information System (INIS)

Determined were effective specific fracture work, critical coefficient of stress intensity in the upper point of the fracture, strength and heat resistance during heat changes (20-1300 deg C) of the material produced by sintering stabilized zirconium dioxide microspheres. Dependence of these characteristics on granulometric composition of microspheres was determined. It was ascertained that the additional introduction of large microspheres into the bulk of small microspheres increased the metal fracture work. Specific work of material fracture progress exceeded specific work of fracture motion initiation. High value of fracture work together with high strength permits to use the material formed of microspheres as structural ceramics

1980-01-01

327

Thermal stability of high temperature structural alloys  

Energy Technology Data Exchange (ETDEWEB)

High temperature structural alloys were evaluated for suitability for long term operation at elevated temperatures. The effect of elevated temperature exposure on the microstructure and mechanical properties of a number of alloys was characterized. Fe-based alloys (330 stainless steel, 800H, and mechanically alloyed MA 956), and Ni-based alloys (Hastelloy X, Haynes 230, Alloy 718, and mechanically alloyed MA 758) were evaluated for room temperature tensile and impact toughness properties after exposure at 750 C for 10,000 hours. Of the Fe-based alloys evaluated, 330 stainless steel and 800H showed secondary carbide (M{sub 23}C{sub 6}) precipitation and a corresponding reduction in ductility and toughness as compared to the as-received condition. Within the group of Ni-based alloys tested, Alloy 718 showed the most dramatic structure change as it formed delta phase during 10,000 hours of exposure at 750 C with significant reductions in strength, ductility, and toughness. Haynes 230 and Hastelloy X showed significant M{sub 23}C{sub 6} carbide precipitation and a resulting reduction in ductility and toughness. Haynes 230 was also evaluated after 10,000 hours of exposure at 850, 950, and 1050 C. For the 750--950 C exposures the M{sub 23}C{sub 6} carbides in Haynes 230 coarsened. This resulted in large reductions in impact strength and ductility for the 750, 850 and 950 C specimens. The 1050 C exposure specimens showed the resolution of M{sub 23}C{sub 6} secondary carbides, and mechanical properties similar to the as-received solution annealed condition.

Jordan, C.E.; Rasefske, R.K.; Castagna, A. [Lockheed Martin Corp., Schenectady, NY (United States)

1999-03-01

328

Alloying effect on structure and mechanical properties of Ni-Co-Al system worked (? + ?) alloys  

International Nuclear Information System (INIS)

A study is made into the effect of alloying with Mo, Nb, Ta, Cr, Ti, Hf on structure phase composition, tensile properties, impact strength and durability of the following heat resistant alloys: 44.1-48.8 mass % Ni; 34.5-40.8 mass % Co; 9.1-13.9 mass % Al. It is revealed that the best results are gained when alloying Ni-Co-Al system with titanium (2-3 mass %) in combination with chromium (? 1 mass %) and additions of Nb/Ta and Mo (0.5 mass % each). These alloys possess high strength and heat resistance (900 deg C) together with high fracture toughness (20 deg C) and stable plasticity in the whole temperature range of 20 to 900 deg C

1999-01-01

329

Development of heat resistant SiC fibers by radiation curing  

International Nuclear Information System (INIS)

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

1994-09-01

330

Degradation Evaluation of Mechanical Properties for 12Cr Ferrite Heat Resisting Steel by Reversible Permeability  

International Nuclear Information System (INIS)

The integrity of the industrial equipment in use under high temperature and high pressure must be assessed by regularly measuring the degraded mechanical properties during service time. In order to nondestructively monitor the degraded mechanical properties of industrial equipment, a measuring method of the reversible permeability(RP) using surface type probe is presented. The method for measuring the RP is based on that RP is the differential value of hysteresis loop. The RP is exactly the foundation harmonics induced in a detecting coil measured by lock-in amplifier tuned to a frequency of the alternating perturbing magnetic field. The peak of RP is measured around the coercive force. Steel material used in this work was 12Cr ferritic heat resisting steel. The eleven kinds of samples aged during different times under same temperature (700 .deg. C) were prepared. Peak interval of reversible permeability(PIRP), Vickers hardness, and tensile strength measured for the aged samples decreased abruptly for short aging time (below 500 h), but the change became small at a ling aging time. Vickers hardness and tensile strength linearly decreased as RIRP decreased, so the degraded mechanical properties of 12Cr ferritic heat resisting steel could be nondestructively evaluated by measuring RIRP

2010-10-01

331

Transcriptome profiling of heat-resistant strain Bacillus licheniformis CGMCC3962 producing Maotai flavor.  

Science.gov (United States)

Although Maotai flavor liquor is exclusive due to its soy sauce flavor, knowledge of its key compound and production mechanism is still scarce until now. To gain insight into the production mechanism of soy sauce flavor, a soy sauce flavor producing strain with high efficiency and heat-resistant capability was obtained, and the metabolic mechanism of the strain was investigated with the technique of microarray profiling. Because high temperature was a key factor for soy sauce flavor production, the global gene expression of this heat-resistant strain fermented at 55 °C was analyzed. Except for the responsive increase of heat shock proteins, which maintained cell survival during heat stress, biosynthesis of cysteine was also up-regulated. In addition, some metabolites were significantly increased when cysteine was added to the fermentation medium, such as 2,3-butanediol, 3-hydroxy-2-butanone, and tetramethylpyrazine, which were important flavor compounds in soy sauce flavor liquor and might be related with soy sauce flavor. The results indicated that cysteine might play an important role in the formation of soy sauce flavor compound, and it might act as an indirect precursor or stimulator of soy sauce flavor formation. This was the first use of the microarray profiling tool to investigate the fermentative strains for Chinese traditional liquor, which would allow a deeper insight into the mechanism of the formation of soy sauce flavor compound. PMID:22283589

Wu, Qun; Xu, Yan

2012-02-29

332

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)

1979-10-01

333

Characteristics of the heat resistant FBG sensor under laser cladding condition  

Science.gov (United States)

We have developed heat resistant strain sensors using laser processing techniques. The application is aimed at structural health monitoring for high temperature piping systems. This situation requires extraordinary durability such as radiation resistance and noise isolation due to adverse conditions caused by nuclear reactions or electro-magnetic pulses. We proposed that a Fiber Bragg Grating (FBG) sensor made by femtosecond laser processing could be the best candidate. The combination of fabric reinforcement and a heatproof adhesive mold successfully protected the fragile optical fiber once the fiber was installed on the piping material's surface. To make the best use of the heat-resistant characteristic, we fixed the FBG sensor by metal mold. A groove was processed onto the surface of a SUS metal plate with a grindstone. We used a Quasi-CW laser to weld a filler wire onto the plate. The optical fiber was situated under the filler wire before was heated by laser pulses with 10 joule energy and a duration of 10 ms. A series of weld pool formed a sealing clad on the groove. The FBG sensor was buried at a depth of 1 mm over a length of 1 cm. No degradation in its reflection spectra was detected before and after the processing. The FBG sensor can detect the vibration of the plate caused by impact shocks. In this paper, the Bragg peak shift of the FBG sensor under laser cladding condition has been discussed.

Nishimura, A.; Terada, T.

2014-02-01

334

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)

1982-01-01

335

An initial investigation of the ultrasonic welding of Tophet C bridgewire to Hastelloy C-276  

Energy Technology Data Exchange (ETDEWEB)

An initial feasibility study has been completed on the ultrasonic welding of Tophet C (Ni-24 Fe-16 Cr) bridgewire to Hastelloy C-276 (Ni-16 Cr-15 Mo-4 W) pin material. A key feature of this work is that it employed a hybrid microcircuitry ultrasonic wire bonder. Much greater productivity can be expected from this process compared with traditional bridgewire welding methods. Three different ultrasonic tool designs were investigated. After selection of the best design, pull test data were acquired for both the 1st and 2nd weld locations in both heel and toe directions. Values up to 94% of the bridgewire tensile strength were obtained. With the equipment used both raised and flat bridgewire configurations are possible. While much work is still necessary to prove in the process for production applications, the work completed to date indicates the ultrasonic welding process merits further investigation. 6 figs.

Knorovsky, G.A.; Kwiatkowski, J.J.

1989-05-01

336

Process of brazing using low temperature braze alloy of gold-indium tin  

International Nuclear Information System (INIS)

A heat resistant brazing alloy of a major amount of gold, a lesser amount of indium and a minor amount of tin. The alloy is particularly suited for use in bonding electrical components to chip carrying substrates which are to be reworked

1985-01-01

337

Forging large disk blanks made of alloy KhN73MBTYu-VD  

Energy Technology Data Exchange (ETDEWEB)

New elements in the technology for vacuum-arc remelting of heat-resistance nickel alloy KhN73MBTYu-VD are described. Research was done on the plasticity properties of the cast alloy. A technology for forging the cast blanks, by upsetting (with the use of plastic liners), is described. The structure and properties of heat-treated disks are discussed.

Barabanov, S.P.; Babinov, V.V.; Podolskii, M.S.; Stanyukovich, N.G.; Tulyankin, F.V.; Varchich, A.V.; Zameshaev, E.V.

1984-01-01

338

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-06-01

339

Morphology of extremely heat-resistant spores from Bacillus sp. ATCC 27380 by scanning and transmission electron microscopy  

Science.gov (United States)

A structural analysis of the internal and external mature spore morphology of an extremely heat resistant Bacillus spore was obtained by both scanning and transmission electron microscopy and is described. With dry heat, 139 hr at 125 C or 13-17 hr at 138 C is required to kill 90% of Bacillus sp. ATCC 27380 spores. A morel-like structure characterized by irregular but distinct polygonal ridges suggestive of extreme dehydration was observed in spore specimens. Some spores also possess a brioche-shaped appendage which is perhaps unique to this species. The explanation of the extreme heat resistance remains unknown, but it is suggested that heat resistance would result if dehydration converts the spore contents into a solid state, either amorphous or quasi-crystalline. The organism was isolated from a surface soil sample.

Youvan, D.; Watanabe, M.; Holmquist, R.

1977-01-01

340

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)

1991-11-05

 
 
 
 
341

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

International Nuclear Information System (INIS)

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

1994-01-01

342

Method of improving the heat resistance of parts working under conditions of discontinuous lubrication  

International Nuclear Information System (INIS)

In the present work the possibilities are studied for using thermochemical treatment methods to improve heat resistance of parts working under conditions of discontinuous lubricant supply. The main aim of the study is to produce rubbing surfaces, the microstructure of which would possess high antifriction as well as antigalling properties. Diffusion impregnation of steel with boron and silicon followed by sulfur impregnation produced two types of coatings. Coatings of the first type are formed at 1000"0C when silicon forces iron boride off the surface, while coatings of the second type are formed at 900"0C when silicon to some degree hinders boron diffusion to the surface. Sulfur diffusion does not affect the surface microstructure. The wear-resistance and galling-resistance of parts subjected to diffusion impregnation with boron, silicon, and sulfur are 1.6-2.1 times higher than for parts subjected to boron impregnation alone

1986-01-01

343

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

1985-01-01

344

Heat-resistant fiber and/or fire retardant synthetic fiber  

Energy Technology Data Exchange (ETDEWEB)

A heat resistant and/or fire retardant synthetic fiber is obtained by a process comprising immersing a polyethylene fiber into a solution of acrylic acid or impregnating a polyethylene fiber with a solution of acrylic acid and irradiating the polyethylene fiber with an ionizing radiation to graft polymerize the polyethylene fiber with at least 15%, based on the weight of the polyethylene fiber, of acrylic acid, or a process comprising irradiating a polyethylene fiber with an ionizing radiation and then immersing the polyethylene fiber into a solution of acrylic acid or impregnating the polyethylene fiber with a solution of acrylic acid to graft polymerize the polyethylene fiber with at least 15%, based on the weight of the polyethylene fiber, of acrylic acid.

Sakurada, I.; Kaji, K.; Okada, T.

1984-08-21

345

Sterile Endophthalmitis in Vitrectomised Eyes due to Suspected Heat Resistant Endotoxins in the Infusion Fluid  

Directory of Open Access Journals (Sweden)

Full Text Available Purpose: To report on to the possibility of development of severe postoperative sterile endophthalmitis due to heat-resistant bacterial endotoxins in commercially available infusion fluids Methods: A case study of 4 eyes that had previously undergone vitreoretinal surgery, which developed clinical endophthalmitis within 18 hours of surgery and two eyes that had vitreous surgery with intraocular gas and did not develop clinical endophthalmitis following intraocular surgery on three consecutive operative days Results: The vitreous samples were sterile, both for bacteria and fungi. The only common supply in all cases was a new batch of Ringer?s lactate infusion fluid. Though the Ringer?s lactate solutions in the same batch were also sterile, the infusion fluids contained abnormally high levels of bacterial endotoxins detected by gel clot method. Conclusion: Commercially available infusion fluid may be sterile, yet contain endotoxins from killed bacteria. This could cause postoperative sterile endophthalmitis.

Patnaik Bijayananda

2004-01-01

346

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

International Nuclear Information System (INIS)

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

1995-01-01

347

CHANGES IN STREPTOMYCES HYGROSCOPICUS 155 ENDOPEPTIDASE AND AMINOPEPTIDASE ACTIVITY AND HEAT RESISTANCE UNDER STARVATION AND INCREASED TEMPERATURE  

Directory of Open Access Journals (Sweden)

Full Text Available The influence of temperature stress and starvation for amino acids, glucose and phosphates, on the heat resistance of mycelium and endo- and aminopeptidase activity of Streptomyces hygroscopicus 155, was studied. The strongest growth inhibition was determined at temperature elevation from 30° to 39°C and at starvation for amino acids. Also these stress treatments mostly induce the heat resistance of the mycelium. A correlation between the intracellular endo- and aminopeptidase activity and decrease in biomass yield was registered. The process of catabolization of proteins, during the adaptation to stress treatments, depends on energy and is stimulated by the presence of Mg2+ ions.

Zdravka Sholeva and Iskra Ivanova

1995-01-01

348

Weldability studies on high performance alloys in thin sheet form  

International Nuclear Information System (INIS)

An investigation was undertaken to study the hot crack susceptibility of thin gage cobalt base and nickel base alloy sheet materials. Weldability tests were conducted on five different heats of Haynes alloy No. 188 (cobalt base) and on one heat of Haynes alloy 625, Hastelloy alloy X and Hastelloy alloy S (nickel base). Sheet gages ranged from 0.035 in. (0.9 mm) to 0.010 in. (0.25 mm)in thickness. Testing was accomplished using an arc spot hot crack susceptibility device. It was found that hot cracking increases as sheet thickness decreases; however, this was shown to be related to the number of grains per cross section rather than thickness, per se. Hot cracking was the most severe when the thickness-to-grain diameter ratio diminished to value of less than 4. Fractographic studies on the cobalt base alloy suggest this may be due to greater ease of intergranular crack propagation when there are only a few grains through the cross section of the sheet. This hypothesis is supported by the observation that the longest individual heat-affected zone cracks were generally found in those materials with the lowest thickness-to-grain diameter ratio. (auth)

1975-09-01

349

Fundamental studies on electron beam welding on heat resistant superalloys for nuclear plants, 6  

International Nuclear Information System (INIS)

In this report, base metal of superalloys for nuclear plants, its electron beam and TIG weld joints were compared with each other in the mechanical properties. Obtained conclusions are summarized as follows: 1) TIG weld joint is superior to electron beam weld joint and base metal in 0.2% proof stress irrespective of the material, and electron beam weld joint is also superior to base metal. There is an appreciable difference in tensile stress between base metal and weld joint regardless of the materials. Meanwhile, electron beam weld joint is superior to TIG weld joint in both elongation and reduction of area. 2) Electron beam weld joint has considerably higher low-cycle fatigue properties at elevated temperatures than TIG weld joint, and it is usually as high as base metal. 3) In the secondary creep rate, base metal of Hastelloy X (HAEM) has higher one than its weld joints. However, electron beam weld joint is nearly comparable to the base metal. 4) There is hardly any appreciable difference between base metal and weld joint in the creep rupture strength without distinction of the material. In the ductility, base metal is much superior and is followed by electron beam weld joint and TIG weld joint in the order of high ductility. However, electron beam weld joint is rather comparable to base metal. 5) In consideration of welded pipe with a circumferential joint, the weld joint should be evaluated in terms of secondary creep rate, elongation and rupture strength. As the weld joint of high creep rupture strength approaches the base metal in the secondary creep rate and the elongation, it seems to be more resistant against the fracture due to creep deformation. In this point of view, electron beam weld joint is far superior to TIG weld joint and nearly comparable to the base metal. (author)

1980-01-01

350

Fundamental studies on electron beam welding on heat-resistant superalloys for nuclear plants, 1  

International Nuclear Information System (INIS)

In this paper, the effect of welding conditions on some characteristics of weld bead in electron beam welding was made clear, concerning such superalloys for the nuclear plants as Hastelloy-type, Inconel-type and Incoloy-type ones. Obtained conclusions may be summarized as follows, using technical symbols which are given meanings in this report. 1) The weld defects are R-porosity at the root of the penetration and a microcrack observed continuously in the interdendritic boundary of weld metal and the grain boundary of heat affected zone. 2) R-porosity occurs within the individual areas on W sub(R)-a sub(b) diagram. Superalloys can be evaluated in the susceptibility to the R-porosity in terms of S sub(P) and ?a sub(b). 3) From the relation between heat input and microcracking percentage, microcracks occur at and below a certain heat input. This critical heat input is herein defined as q sub(cr) to avoid microcracks which is regarded as one of the proper criteria to evaluate the superalloys in the susceptibility to microcracking. 4) Most microcracks are apt to occur when h sub(C)/h sub(N) comes near to 1.0. When microcracking position is arranged on h sub(P)-h sub(P) diagram, h sub(C)/h sub(P) generally tends to decrease with the increase in h sub(P) in all the superalloys except for Incoloy 800. Moreover, this value is scattered in the individual area of h sub(N)/h sub(P). (auth.)

1978-01-01

351

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

1998-01-01

352

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

Energy Technology Data Exchange (ETDEWEB)

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.

Taylor, C.L.

1991-04-01

353

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

1980-01-01

354

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)

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).

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

355

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

International Nuclear Information System (INIS)

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

1981-01-01

356

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)

1990-01-01

357

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

Science.gov (United States)

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.

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

2013-04-01

358

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

DEFF Research Database (Denmark)

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.

Samson, R.A.; Houbraken, J.

2009-01-01

359

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

International Nuclear Information System (INIS)

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

1989-01-01

360

Tracking heat-resistant, cold-thriving fluid milk spoilage bacteria from farm to packaged product.  

Science.gov (United States)

Control of psychrotolerant endospore-forming spoilage bacteria, particularly Bacillus and Paenibacillus spp., is economically important to the dairy industry. These microbes form endospores that can survive high-temperature, short-time pasteurization; hence, their presence in raw milk represents a major potential cause of milk spoilage. A previously developed culture-dependent selection strategy and an rpoB sequence-based subtyping method were applied to bacterial isolates obtained from environmental samples collected on a New York State dairy farm. A total of 54 different rpoB allelic types putatively identified as Bacillus (75% of isolates), Paenibacillus (24%), and Sporosarcina spp. (1%) were identified among 93 isolates. Assembly of a broader data set, including 93 dairy farm isolates, 57 raw milk tank truck isolates, 138 dairy plant storage silo isolates, and 336 pasteurized milk isolates, identified a total of 154 rpoB allelic types, representing an extensive diversity of Bacillus and Paenibacillus spp. Our molecular subtype data clearly showed that certain endospore-forming bacterial subtypes are present in the dairy farm environment as well as in the processing plant. The potential for entry of these ubiquitous heat-resistant spoilage organisms into milk production and processing systems, from the dairy farm to the processing plant, represents a considerable challenge that will require a comprehensive farm-to-table approach to fluid milk quality. PMID:18292280

Huck, J R; Sonnen, M; Boor, K J

2008-03-01

 
 
 
 
361

The role of heat resistance in thermorestoration of hydrated bacterial spores  

International Nuclear Information System (INIS)

This study for the first time presents evidence of the distinct role played in thermorestoration by cellular determinants such as the resistance to heat and radiation, and the ionic state of spores. In the past only radiochemical determinants associated with radical annealment have been studied in hydrated systems. The basic heat resistance of spores plays a significant role in the precipitous drop in spore survival due to 0.45 Mrad radiation plus heat above 65-750C for B.cereus and 75-950C for B.stearothermophilus. The effect of the spores radiation resistance was not distinct except in the frozen state and at the saturation plateau of thermorestoration where the radiation resistant B.cereus showed ca. 1 log cycle higher survival than the radiation sensitive B.stearothermophilus. When spores are chemically converted into their H+ and Ca++ ionic forms, the H+ spores are distinctly more responsive than Ca++ spores to processes of radical annealment responsible for thermorestoration in hydrated spore systems. At temperatures of extensive thermorestoration of water radicals, H+ spores showed higher survival than Ca++ spores. (F.J.)

1972-09-18

362

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

International Nuclear Information System (INIS)

In this paper, the effect of the welding conditions on the characteristics of the weld geometry and the weld defects was made clear, concerning the heat-resistant superalloys for the nuclear plants. Obtained conclusion may be summarized as follows, using technical symbols which are given meaning in this report. 1) The weld defects were R-porosity and microcrack. 2) S sub(p) and ?a sub(b) are considered to be the important criteria for the evaluation of the susceptibility to the R-porosity. 3) Superalloys could be evaluated in the sensitivity to the microcrack in terms of the critical heat input to avoid microcrack q sub(cr). This q sub(cr) is considered to be one of the proper criteria for evaluating the superalloys in the susceptibility to the microcrack. 4) Most microcracks were apt to occur when h sub(c)/h sub(N) came near to 1.0. These microcracks came to occur easily with the increase of d sub(B.N)/d sub(B). (auth.)

1976-01-01

363

Influence of carburisation on the ductility of four high temperature alloys  

International Nuclear Information System (INIS)

The influence of carburisation and thermal exposure on the room temperature ductility of Alloy 800 H, Inconel 617, Hastelloy X and Nimonic 86 has been investigated. It was found that carburisation affects the ductility of Alloy 800 H much less severely than that of the nickel-base alloys. This is explained in terms of the varying volume fractions of carbide formed for a particular carbon content as the result of, first, different carbon solubilities in the iron and nickel-base materials and, second, the formation of carbides with different metal: carbon stoichiometry ratios. (author)

1981-01-01

364

Thermogravimetric Study of Oxidation-Resistant Alloys for High-Temperature Solar Receivers  

Science.gov (United States)

Three special alloys likely to be suitable for high-temperature solar receivers were studied for their resistance to oxidation up to a temperature of 1050°C in dry atmospheres of CO2 and air. The alloys were Haynes HR160, Hastelloy X, and Haynes 230, all nickel-based alloys with greater than 20% chromium content. The oxidation rate of specimens cut from sample master alloys was followed by thermogravimetry by continuously monitoring the weight change with a microbalance for a test duration of 10 h. The corrosion resistance was deduced from the total weight increase of the specimens and the morphology of the oxide scale. The surface oxide layer formed (scale) was characterized by scanning electron microscopy and energy dispersive x-ray spectroscopy and in all cases was found to be chromia. Oxidation was analyzed by means of parabolic rate law, albeit in some instances linear breakaway corrosion was also observed. For the temperature range investigated, all alloys corroded more in CO2 than in air due to the formation of a stronger and more protective oxide scale in the presence of air. At 1000°C, the most resistant alloy to corrosion in CO2 was Haynes 230. Alloy Haynes HR160 was the most oxidized alloy at 1000°C in both CO2 and air. Hastelloy X oxidized to a similar extent in CO2 at both 900°C and 1000°C, but in air, it resisted oxidation better at 1000°C than either at 900°C or 1000°C.

Olivares, Rene I.; Stein, Wes; Marvig, Paul

2013-12-01

365

Cr - Ni system alloys composition impact on durability value  

Directory of Open Access Journals (Sweden)

Full Text Available There are considered the alloys of the Cr – Ni system with addition of iron, molybdenum and other alloying elements. In the alloys there varied chrome content from 35 to 55 %. The alloys were subjected to various types of heat treatment. There were measured mechanical properties at the room temperature, then the alloys were studied for the durability limit. There was additionally studied the impact of chrome content in the alloy and operation temperatures on the value of rupture stress. All the indicators studied were compared with similar parameters of the ??77??? alloy.It was established that in terms of heat resistance with the present combination of alloying elements the most optimal chrome content is 40…45 %.

A. Z. Issagulov

2014-10-01

366

Superconductivity mediated by a soft phonon mode: Specific heat, resistivity, thermal expansion, and magnetization of Y B6  

Science.gov (United States)

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 2to300K , using a single crystal with Tc=7.2K . 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 F(?) , the spectral electron-phonon scattering function ?tr2F(?) , and the phonon density of states weighted by the frequency-dependent Grüneisen parameter ?G(?)F(?) , respectively. Lattice vibrations extend to high frequencies >100meV , but a dominant Einstein-like mode at ˜8meV , 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.

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

2006-01-01

367

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

CERN Document Server

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.

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

368

Attachment and Heat Resistance of Campylobacter jejuni on Enterococcus faecium Biofilm  

Directory of Open Access Journals (Sweden)

Full Text Available Attachment and heat resistance of Campylobacter jejuni in Enterococcus faecium biofilm were studied. E. faecium biofilm were incubated with 107 cfu mL-1 C. jejuni for 4.5 h at 23 ° C under atmospheric conditions or 12 h at 42 ° C under microaerophilic conditions. The coupons were heat treated at 56 and 63 ° C for 30, 60 and 120 sec. In addition, C. jejuni in E. faecium biofilm was incubated for up to 4 days at 23 ° C under atmospheric conditions in 50% trypticase soy broth for survival study. Hydrophobicity of C. jejuni planktonic cells, E. faecium planktonic and biofilm cells, as determined by salt aggregation test and microbial adhesion to hydrocarbon test using hexadecane were determined. D-value of C. jejuni planktonic cells at 56 and 63 ° C were 46 and 12 sec, respectively. D-value of E. faecium planktonic cells at 56 and 63 ° C were 117 and 80 sec, respectively. The presence of E. faecium biofilm reduced the lethal effect of heat on C. jejuni cells when heated at 56 and 63 ° C. C. jejuni formed biofilm on stainless steel when grown at 42 ° C under microaerophilic conditions for 12 h but the biofilm did not survive the heat treatments nor did C. jejuni cells in E. faecium biofilm. C. jejuni in biofilm persisted under atmospheric condition at 23 ° C for up to 2 days while C. jejuni attached on stainless steel without biofilm could not be recovered after two days of incubation. After forming E. faecium biofilm, became more hydrophobic than its planktonic cells. This may attract C. jejuni cells to attach on the biofilm as C. jejuni was found to be more hydrophobic than E. faecium planktonic cells.

N. Trachoo

2005-01-01

369

Nonmagnetic heating-resistant stainless steel for roller bearings; Nichtmagnetisierbarer warmbestaendiger nichtrostender Stahl fuer Waelzlager  

Energy Technology Data Exchange (ETDEWEB)

A low cost austenitic chromium manganese steel with about 1 mass% of carbon and nitrogen was molten under normal pressure which reveals an amazing combination of properties. Starting from a yield strength of about 600 MPa it is cold work hardened to 60 HRC. This high hardness is brought about for the first time without a martensitic microstructure which is usual for roller bearings. In addition this steel is stainless, non-magnetic and heating resistant up to about 500 C, i.e. a material to serve under complex loading. Manufacturing by ingot metallurgy, ESR, hot working, solution annealing and machining was carried out on an industrial scale. The investigation of the structure was carried out on several scales, beginning with the electronic structure, the TEM structure, the light optical microscopy up to macroetchings. In this manner an extensive understanding of the outstanding combination of properties of the steel named CARNIT was derived. (Abstract Copyright [2008], Wiley Periodicals, Inc.) [German] Durch Legieren von Chrom-Mangan-Staehlen mit rund 1 % Kohlenstoff und Stickstoff wurde ein kostenguenstiger, unter Normaldruck erschmelzbarer austenitischer Stahl entwickelt, der ueber eine neue und erstaunliche Eigenschaftskombination verfuegt. Ausgehend von einer Streckgrenze um 600 MPa laesst er sich durch Kaltverformen auf eine Haerte von 60 HRC verfestigen. Diese hohe Haerte wird erstmals ohne das fuer Waelzlager uebliche Martensitgefuege erzielt. Er ist ausserdem nichtrostend, nichtmagnetisierbar und bis rund 500 C warmbestaendig, d. h. ein Werkstoff fuer komplexe Betriebsbedingungen. Die Herstellbarkeit durch Blockguss, ESU, Warmumformen, Loesungsgluehen und Drehbearbeiten wurde im industriellen Massstab nachgewiesen. Die Untersuchung der Struktur des neuen Stahles erfolgte mehrskalig, beginnend bei der Elektronenstruktur und weiter ueber die Feinstruktur im Elektronenmikroskop, die Mikrostruktur im Lichtmikroskop bis hin zur Makroaetzung. So konnte ein weitgehendes Verstaendnis fuer die aussergewoehnliche Eigenschaftskombination des neuen, mit CARNIT bezeichneten Stahles gewonnen werden. (Abstract Copyright [2008], Wiley Periodicals, Inc.)

Berns, H. [Lehrstuhl Werkstofftechnik, Ruhr-Universitaet Bochum (Germany); Tyshchenko, A.I.; Gavriljuk, V.G. [Institut fuer Metallphysik, Kiev (Ukraine); Schulte-Noelle, C.; Trojahn, W. [Schaeffler Gruppe, Schweinfurt (Germany); Riedner, S.

2008-07-15

370

Heat-resisting ferrite steel for thermonuclear reactor and method of manufacturing the same  

International Nuclear Information System (INIS)

The present invention provides a heat-resistant steel containing tantalum oxide as dispersing particles which minimize the amount of Ni, Cu, Mo, Nb, Hf, Al, Co and Ag as elements deleterious to reduction of activation, and improves the strength by a dispersion reinforcing mechanism. Tantalum oxide is selected because it has a specific gravity of about 8, which is slightly heavier than iron, so that it does not rise as slugs even if it is added into molten steel, it is less activated, and stable for a long period of time in the steel. Moreover, the amount of each of the constituent elements is limited to an appropriate range. That is, it comprises 0.05 - 0.15% of C, 0.02 - 0.25% of Si, 0.01 - 0.50% of Mn, not more that 0.01% of P, not more than 0.01% of S, 5.0 - 13.0% of Cr, 0.3 - 3.0% of W, 0.05 - 0.40% of V, 0.002 - 0.08% of N, 0.3 - 2.5% of tantalum oxide having a grain size of not greater than 1?m, 0.25 - 3.0% of Ta in total, and the balance of iron and inevitable impurities. This can remarkably improve the strength at high temperature, especially, creep rupture strength at high temperature compared with the prior art and, in addition, a material having excellent toughness and fabricability can be attained. (T.M.)

1993-11-29

371

Optimum Irrigation Scheduling for CRIS-134, A New Heat Resistant Cotton Variety of Sindh in Sakrand Conditions  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A field experiment was conducted to evaluate the different dates of initial irrigation and later irrigation frequencies on seedcotton yield of CRIS-134, an advance heat resistant variety. On an average, data revealed that CRIS-134 significantly responded to first irrigation at 45 days after planting (DAP) and yielded highest (2429 kg ha -1). As regards interval between subsequent irrigations, results revealed that averagely CRIS-134 produced significantly highest yield of 2230 kg h...

Memon, A. M.; Soomro, A. R.; Soomro, A. W.; Rehana Anjum; Saira Bano Babar

2001-01-01

372

Optimum Irrigation Scheduling for CRIS-134, A New Heat Resistant Cotton Variety of Sindh in Sakrand Conditions  

Directory of Open Access Journals (Sweden)

Full Text Available A field experiment was conducted to evaluate the different dates of initial irrigation and later irrigation frequencies on seedcotton yield of CRIS-134, an advance heat resistant variety. On an average, data revealed that CRIS-134 significantly responded to first irrigation at 45 days after planting (DAP and yielded highest (2429 kg ha -1. As regards interval between subsequent irrigations, results revealed that averagely CRIS-134 produced significantly highest yield of 2230 kg ha -1 at every two weeks interval.

A. M. Memon

2001-01-01

373

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Metallurgical evaluation was performed on a fractured column tube of the reformer furnace in an ammonia plant. The tubes were manufactured from centrifugally cast heat resistant steel HK 40. Optical and scanning electron microscope (SEM) were used for microstructural and fracture analysis. For composition determination of the microconstituents energy dispersive X ray spectroscopy (EDS) was used. To evaluate mechanical properties, hardness and microhardness measurements were performed. Investi...

Odanovic?, Z.; Blac?ic?, I.; Vrac?aric?, D.; Grabulov, V.; Burzic?, M.; Katavic?, B.

2010-01-01

374

Investigation of several commercial aluminide coatings for carburization protection of a nickel-base alloy  

International Nuclear Information System (INIS)

Four commercial aluminide coatings applied to Hastelloy Alloy X were investigated with respect to their carburization resistance in a carburizing impure helium environment. The test gas was helium with 500 ?atm H2, 50 ?atm CO, 50 ?atm CH4, and 2O. The uncoated specimens exposed to this test environment at 9000C (16500F) for 1000 and 2000 h exhibited significant carburization. All four coatings provided good protection against carburization of the substrate Hastelloy Alloy X, presumably due to the formation of an Al2O3 oxide scale on the coating surface during the high-temperature corrosion exposure. The Al2O3 oxide is believed to be an effective barrier to carbon transport. Aluminide coatings applied to Hastelloy Alloy X exhibited a tendency for forming Kirkendall diffusion voids (or pores) in the diffusion zone during long-term high-temperature exposures [e.g., 9000C (16500F) for 1000 h]. Chromium addition during aluminizing, which resulted in a high chromium content in the coating, appears to be effective in preventing the pore formation during subsequent long-term high-temperature exposures

1980-01-01

375

Heat resistance of polyethylene ski sliding sheet and cable in radiation-induced crosslinking with a promoter containing dipropargyl maleate  

International Nuclear Information System (INIS)

A new developed method of radiation-induced crosslinking with the promoter(crosslinker) containing dipropargyl maleate as essential was used in producing a polyethylene ski sliding sheet and a cable with improved heat resistance. Promoting effect of the crosslinker was first studied, and then physical and chemical properties of the crosslinker, its acute toxicity upon mice and its mixing with polyethylene were investigated. The radiation dose for its complete fixation was determined by measuring its elution from the specimen into hot water. Heat resistance necessary for ski sliding sheets is obtainable in the crosslinking gel fraction of 30 - 40%, which is attained by 0.5 Mrad(under nitrogen) or 2.5 Mrad(in air) irradiation in the presence of the crosslinker. Sliding sheet obtained exhibits extreme adhesion to a metal. Flame resistance of the cable is largely influenced by crosslink distribution. Its incombusitibility can be remarkably improved by means of the two layers; the inner one having a higher degree of crosslinking than the outer. Addition of diallyl phthalate in small quantity to the crosslinker further raises heat resistance of the cable. (auth.)

1976-01-01

376

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)

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.

Yastreb T.O.

2012-08-01

377

The expression of the 70 kd heat shock proteins is altered in heat resistant HA-1 cells  

International Nuclear Information System (INIS)

The authors have recently isolated a series of stable heat resistant variants from HA-1 Chinese hamster cells. Examination of two dimensional gels of total cell extracts indicated that the 70kd family of HSP were expressed at higher levels in these variants. After a mild heat treatment the maximal amounts of 70 kd HSP induced and the kinetics of induction were different in the variant lines. Essentially, the level of increase was greater and it occured sooner. A similar situation was observed in cells treated with HSP inducers other than heat, such as sodium arsenite and amino acid analogues. Short pulse labeling and pulse-chase experiments indicated that the alterations in 70 kd HSP expression in the variant lines were probably at the level of synthesis of the protein, not its degradation. Total cellular RNA was isolated from control and heated HA-1 cells and their heat resistant variants and was translated in vitro. Preliminary results indicate that the changes in 70 kd HSP synthesis observed in the heat resistant variants seem to be a reflection of altered levels of the respective mRNAs. Moreover, the authors also found that heated cells preferentially express the HSP mRNAs. This observation suggests that translational controls may play a role in the preferential synthesis of HSP in heated cells

1984-03-01

378

Application of heat-resistant materials to a hypersonic flight experiment vehicle; Tainetsu zairyo no HYFLEX (gokuchoonsoku jikkenki) eno tekiyo  

Energy Technology Data Exchange (ETDEWEB)

Shuttling vehicles such as the space shuttle that have to make reentry necessitate reusable materials for the construction of their heat-resistant structures and thermal protection systems that will withstand the intense aerodynamic heating. Similar heat-resistant materials are also necessary for the embodiment of the Japanese version space shuttle (HOPE). Kawasaki Heavy Industries, Ltd., participating in the project of the Hypersonic Flight Experiment (HYFLEX) vehicle which is the precursor to the HOPE, developed, manufactured, and installed ceramic tiles and carbon/carbon (C/C) materials, and delivered the HYFLEX aft fuselage and C/C elevons. The HYFLEX test flight was carried out with success. In this report, out of the technologies for applying heat-resistant materials to the HYFLEX, the ceramic tile and C/C material are also discussed. The service temperature upper limits of the C/C materials, ceramic tiles, and flexible heat insulating materials are 1650degC, 1400degC, and 800degC, respectively. Also discussed in this paper are the manufacture of ceramic tile base, ceramic tile fabrication, coating technology, ceramic tile installation technology, and application of C/C composites to the HYFLEX. It is inferred that they all functioned satisfactorily in the flight test. 3 refs., 13 figs., 2 tabs.

Takagi, K.; Kimoto, J.; Imuta, M.; Tajima, N.; Oku, Y.; Murai, A. [Kawasaki Heavy Industries, Ltd., Kobe (Japan)

1997-07-20

379

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)

1994-11-25

380

Data processing in evaluation of heat resistance of W-containing coatings  

International Nuclear Information System (INIS)

A comparative analysis of kinetic regularities equations used in isothermal testings for determination of the ratio of sample mass growth with coatings is performed. A possibility of forecasting the coatings durability on the basis of values of samples mass growth ratio is determined. As a substrate material, carbon steel U8 was used. For surface electrospark alloying W - Cr; W - Ni; W - Cr- Mo tungsten-containing alloys were used. The thickness of coatings is 15 ?m. It is shown that an increase in the rate of mass growth can be explained by the beginning of the process of the coating complete fracture

2002-03-01

 
 
 
 
381

Salt Fog Testing Iron-Based Amorphous Alloys  

International Nuclear Information System (INIS)

Iron-based amorphous alloys are hard and highly corrosion resistant, which make them desirable for salt water and other applications. These alloys can be produced as powder and can be deposited as coatings on any surface that needs to be protected from the environment. It was of interest to examine the behavior of these amorphous alloys in the standard salt-fog testing ASTM B 117. Three different amorphous coating compositions were deposited on 316L SS coupons and exposed for many cycles of the salt fog test. Other common engineering alloys such as 1018 carbon steel, 316L SS and Hastelloy C-22 were also tested together with the amorphous coatings. Results show that amorphous coatings are resistant to rusting in salt fog. Partial devitrification may be responsible for isolated rust spots in one of the coatings. (authors)

2006-12-01

382

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

Directory of Open Access Journals (Sweden)

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

Basim A. Khidhir

2010-01-01

383

Wettability and interface considerations in advanced heat-resistant Ni-base composites  

International Nuclear Information System (INIS)

Oxide fiber-reinforced Ni-base composites have long been considered as attractive heat-resistant materials. After several decades of active research, however, interest in these materials began to decline around mid-1990's due chiefly to 1) a lack of manufacturing technology to grow inexpensive single-crystal oxide fibers to be used in structural composites, and 2) fiber strength loss during processing due to chemical interactions with reactive solutes in the matrix. The cost disadvantage has been mitigated to a large extent by the development of innovative fiber fabrication processes such as the Internal Crystallization Method (ICM) that produces monocrystalline oxide fibers in a cost-effective manner. Fiber strength loss has been an equally restrictive issue but recent work has shown that it may be possible to design creep-resistant composites even when fiber surface reconstruction from chemical interactions has degraded the strength of extracted fibers tested outside the matrix. The key issue is the optimization of the composite- and interface structure. Reaction-formed defects may be healed by the matrix (or a suitable coating material) so that the fiber residing in the matrix may exhibit diminished sensitivity to flaws as compared to fibers extracted from the matrix and tested in isolation of the matrix. Generally, the Ni-base/Al2O3 composites exhibit acceptable levels of wettability and interface strength (further improved with the aid of reactive solutes), which are required for elevated-temperature creep-resistance. In order to harness the full potential of these composites, the quality of the interface as manifested in the fiber/matrix wettability, interface composition, interphase morphology, and interface strength must be designed. We identify key issues related to the measurement of contact angle, interface strength, and chemical and structural properties at the fiber/matrix interface in the Ni/alumina composites, and present the current state-of the-art in understanding and designing the Ni/alumina interface. There should be no doubt that optimization of the interface- and composite microstructure through judicious control of the fabrication process and surface modification shall yield technologically promising Ni-base/oxide fiber composites. (authors)

2006-01-01

384

Use of Bremsstrahlung induced by the 147Pm ?-particles in the evaluation of heat resistance of aluminium coatings assisted by shot-blasting  

International Nuclear Information System (INIS)

Nondestructive analysis of aluminium coating heat resistance sprayed on the basis after shot-blasting is proposed. Physical essence of the procedure is based on the estimation of weight of the coating by means of radioisotope parameters. Application of the procedure for the estimation of heat resistance of turbine blades is tested. Technical control allows coating quality estimation during 2-3 minutes with the error on the level of wight method

2007-01-01

385

Oxidation protection for niobium and its alloys at high temperature  

International Nuclear Information System (INIS)

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

1987-01-01

386

The identification and characterization of Clostridium perfringens by real-time PCR, location of enterotoxin gene, and heat resistance.  

Science.gov (United States)

Clostridium perfringens carrying the enterotoxin gene is an important cause of both foodborne and non-foodborne diarrheal disease. Rapid identification of isolates carrying the enterotoxin gene is invaluable for outbreak investigation whilst information on the genomic location of the enterotoxin (cpe) gene can improve our understanding of disease transmission. This paper describes the validation of a real-time polymerase chain reaction (PCR) assay for the identification of C. perfringens and assessment of the potential to cause diarrhea, together with an investigation into the genomic location of the cpe genes in isolates from confirmed incidents of C. perfringens diarrhea. The real-time assay was shown to be specific for the identification of 253 C. perfringens cultures and gave results concordant with those from motility nitrate and lactose gelatine media, the Nagler reaction, and a conventional block-based PCR assay. The cpe gene was detected in 223 of 253 C. perfringens cultures isolated in association with human gastrointestinal disease. A subset of cpe-positive C. perfringens isolates associated with separate incidents of diarrheal disease were investigated further for plasmid or chromosomal location of the cpe gene using a multiplex PCR assay. The cpe gene was plasmid encoded in two isolates from cases of sporadic diarrhea and six isolates from cases of food poisoning. The cpe gene from the remaining 11 isolates from different food poisoning outbreaks was found to be chromosomally encoded. One of the C. perfringens strains with a plasmid encoded cpe gene formed spores of high heat resistance and five formed spores that were sensitive to heating. Eight of the isolates with a chromosomal cpe gene formed heat-resistant spores, and two formed spores with an intermediate heat resistance. PMID:18681798

Grant, Kathie A; Kenyon, Sarah; Nwafor, Ijeoma; Plowman, June; Ohai, Charles; Halford-Maw, Robin; Peck, Michael W; McLauchlin, Jim

2008-10-01

387

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

International Nuclear Information System (INIS)

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

1990-09-01

388

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

Science.gov (United States)

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.

Calle, Luz

1990-01-01

389

Low-alloy copper alloy for operation in the conditions of durable temperature effect and temperature cycling  

International Nuclear Information System (INIS)

Low-alloyed copper alloy having high level of electric conductivity and heat resistance is studied. The effect of continuous durable holding and temperature cycling at the temperature between 300 and 600 Deg C in the air, vacuum and protective nitrogen atmosphere is examined. It is shown that protective nitrogen atmosphere and vacuum equally don't effect on studying properties. Working capacity alloy for its application as insulated and non-insulated wires in windings of high-temperature electromagnetic pumps is shown

2001-06-01

390

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

Energy Technology Data Exchange (ETDEWEB)

This report provides the results of a preliminary phase of a project supporting the Advanced Nuclear Fuel Cycle Technology Initiative at ANL. The project targets the Generation IV nuclear energy systems, particularly the area of reducing the cost of sodium-cooled fast-reactors by utilizing innovative materials. The main goal of the project is to provide the nuclear heat exchanger designers a simplified means to quantify the cost advantages of the recently developed high strength and heat resistant ferritic steels with 9 to 13% chromium content. The emphasis in the preliminary phase is on two steels that show distinctive advantages and have been proposed as candidate materials for heat exchangers and also for reactor vessels and near-core components of Gen IV reactors. These steels are the 12Cr-2W (HCM12A) and 9Cr-1MoVNb (modified 9Cr-1Mo). When these steels are in tube form, they are referred to in ASTM Standards as T122 and T91, respectively. A simple thermal-hydraulics analytical model of a counter-flow, shell-and-tube, once-through type superheated steam generator is developed to determine the required tube length and tube wall temperature profile. The single-tube model calculations are then extended to cover the following design criteria: (i) ratio of the tube stress due to water/steam pressure to the ASME B&PV Code allowable stress, (ii) ratio of the strain due to through-tube-wall temperature differences to the material fatigue limit, (iii) overall differential thermal expansion between the tube and shell, and (iv) total amount of tube material required for the specified heat exchanger thermal power. Calculations were done for a 292 MW steam generator design with 2200 tubes and a steam exit condition of 457 C and 16 MPa. The calculations were performed with the tubes made of the two advanced ferritic steels, 12Cr-2W and 9Cr-1MoVNb, and of the most commonly used steel, 2 1/4Cr-1Mo. Compared to the 2 1/4Cr-1Mo results, the 12Cr-2W tubes required 29% less material and the 9Cr-1MoVNb tubes required 25% less material. Also, with the advanced steels, the thermal strains in the tubes and differential thermal expansion between tubes and shell were significantly better. For steam generators with higher steam exit temperatures, the benefits of the advanced steels become much larger. A thorough search for the thermal and mechanical properties of the two advanced steels was conducted. A summary of the search results is provided. It shows what is presently known about these two advanced steels and what still needs to be determined so that they can be used in nuclear heat exchanger designs. Possible follow up steps are outlined.

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

2004-12-22

391

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

International Nuclear Information System (INIS)

This report provides the results of a preliminary phase of a project supporting the Advanced Nuclear Fuel Cycle Technology Initiative at ANL. The project targets the Generation IV nuclear energy systems, particularly the area of reducing the cost of sodium-cooled fast-reactors by utilizing innovative materials. The main goal of the project is to provide the nuclear heat exchanger designers a simplified means to quantify the cost advantages of the recently developed high strength and heat resistant ferritic steels with 9 to 13% chromium content. The emphasis in the preliminary phase is on two steels that show distinctive advantages and have been proposed as candidate materials for heat exchangers and also for reactor vessels and near-core components of Gen IV reactors. These steels are the 12Cr-2W (HCM12A) and 9Cr-1MoVNb (modified 9Cr-1Mo). When these steels are in tube form, they are referred to in ASTM Standards as T122 and T91, respectively. A simple thermal-hydraulics analytical model of a counter-flow, shell-and-tube, once-through type superheated steam generator is developed to determine the required tube length and tube wall temperature profile. The single-tube model calculations are then extended to cover the following design criteria: (i) ratio of the tube stress due to water/steam pressure to the ASME BandPV Code allowable stress, (ii) ratio of the strain due to through-tube-wall temperature differences to the material fatigue limit, (iii) overall differential thermal expansion between the tube and shell, and (iv) total amount of tube material required for the specified heat exchanger thermal power. Calculations were done for a 292 MW steam generator design with 2200 tubes and a steam exit condition of 457 C and 16 MPa. The calculations were performed with the tubes made of the two advanced ferritic steels, 12Cr-2W and 9Cr-1MoVNb, and of the most commonly used steel, 2 1/4Cr-1Mo. Compared to the 2 1/4Cr-1Mo results, the 12Cr-2W tubes required 29% less material and the 9Cr-1MoVNb tubes required 25% less material. Also, with the advanced steels, the thermal strains in the tubes and differential thermal expansion between tubes and shell were significantly better. For steam generators with higher steam exit temperatures, the benefits of the advanced steels become much larger. A thorough search for the thermal and mechanical properties of the two advanced steels was conducted. A summary of the search results is provided. It shows what is presently known about these two advanced steels and what still needs to be determined so that they can be used in nuclear heat exchanger designs. Possible follow up steps are outlined

2004-01-01

392

Precipitation hardening in welded joints of electroslag remelted 12K1MF-Sh heat resisting steel on reheating  

Energy Technology Data Exchange (ETDEWEB)

Precipitation hardening in commercial welded joints of heat resisting 12Kh1MF-Sh steels under high temperature service conditions as well as microstructure of a weld zone in initial state were investigated. It is shown that high temperature tempering (710-740 deg C, 3h) prevents precipitation hardening in 12Kh1MF- Sh weld metal during long-term service up to 2x10/sup 5/h at 565 deg C, decreases a hardness level of weld metal and a heat affected zone and stabilizes hardness on aging.

Khromchenko, F.A.; Brodskaya, G.L.

1982-03-01

393

Precipitation hardening in welded joints of electroslag remelted 12K1MF-Sh heat resisting steel on reheating  

International Nuclear Information System (INIS)

Precipitation hardening in commercial welded joints of heat resisting 12Kh1MF-Sh steels under high temperature service conditions as iell as microstructure of a weld zone in initial state were investigated. It is shown that high temperature tempering (710-740 deg C, 3h) prevents precipitation hardening in 12Kh1MF- Sh weld metal during long-term service up to 2x10"5h at 565 deg C, decreases a hardness level of weld metal and a heat affected zone and stabilizes hardness on aging

1982-03-01

394

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

International Nuclear Information System (INIS)

The present study was undertaken to evaluate the effect of gamma irradiation on two heat-resistant moulds, namely Aspergillus fumigatus and Paecilomyces variotii isolated from margarine samples. The irradiation process of these moulds was carried out in a 60Co gamma (?) irradiator at average absorbed doses of 1, 3, 5 and 7 kGy for exposure times of 52, 156, 260 and 364 min, respectively. The average D10 value for A. fumigatus was 1.08±0.08 kGy while it was 0.59±0.10 kGy for P. variotii. Consequently, the sensitivity of P. variotii against ? irradiation was more than A. fumigatus

2008-05-01

395

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

Science.gov (United States)

The present study was undertaken to evaluate the effect of gamma irradiation on two heat-resistant moulds, namely Aspergillus fumigatus and Paecilomyces variotii isolated from margarine samples. The irradiation process of these moulds was carried out in a 60Co gamma ( ?) irradiator at average absorbed doses of 1, 3, 5 and 7 kGy for exposure times of 52, 156, 260 and 364 min, respectively. The average D10 value for A. fumigatus was 1.08±0.08 kGy while it was 0.59±0.10 kGy for P. variotii. Consequently, the sensitivity of P. variotii against ? irradiation was more than A. fumigatus.

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

2008-05-01

396

In situ investigation of structure and stability of niobium carbonitrides in an austenitic heat-resistant steel  

International Nuclear Information System (INIS)

The structure and stability of Nb(C,N) precipitates were direct observed during reheating of an austenitic heat-resistant steel using in situ hybrid observations. The coarsened ?-Nb(C,N) and finer ?-Nb(C,N) were present in as-received steel. During the coarsening process, the d-spacing of cubic ?-Nb(C,N) exhibits a sharp decrease with increasing temperature, while that of hexagonal ?-Nb(C,N) maintains a steady increase. Compared to ?-Nb(C,N), the ?-Nb(C,N) was quickly dissolved into the austenite during heating, and it would no longer reprecipitate in the subsequent cooling.

2012-07-01

397

Wrought stainless steel compositions having engineered microstructures for improved heat resistance  

Science.gov (United States)

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.

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

2007-08-21

398

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

1978-01-01

399

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

2002-01-01

400

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

1982-01-01

 
 
 
 
401

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

Energy Technology Data Exchange (ETDEWEB)

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.

Tai Asayama; Yukio Tachibana

2007-09-30

402

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.

2007-01-01

403

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

1996-01-01

404

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

International Nuclear Information System (INIS)

Aluminophosphate glass with a batch composition of 30CaO·15Al2O3·5Fe2O3·25PbO·25P2O5 was prepared as a potential host for the high-level nuclear wastes. This ''base glass'' consists of highly heat-resistant 60CaO·(40-x)Al2O3·xFe2O3 glass and water-resistant lead metaphosphate glass, Pb(PO3)2, which is known to have -103 times higher water-resistivity than conventional borosilicate glass. Two crystallization temperatures (Tc) of 650-671 and 668-693 degC were determined from the differential thermal analysis (DTA) of the ''base glass''. Large activation energies of 4.2 and 4.9 eV were obtained from a Kissinger plot of the Tc values. Nuclear waste ''model glass'' containing 10 stable isotopes with the mass numbers of 90-100 (Sr, Y, Zr, Nb, Mo) and 135-145 (Ba, La, Ce, Pr, Nd) also shows high heat-resistivity. 57Fe Mossbauer spectrum indicates that Fe(III) and Fe(II) are ionically bonded to distorted PO4 tetrahedra at the sites of network modifier. (author)

1999-05-01

405

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)

2010-01-01

406

Heat Resistance in Liquids of Enterococcus spp., Listeria spp., Escherichia coli, Yersinia enterocolitica, Salmonella spp. and Campylobacter spp  

Directory of Open Access Journals (Sweden)

Full Text Available The aim of the work was to collect, evaluate, summarize and compare heat resistance data reported for Campylobacter, Enterococcus, Escherichia, Listeria, Salmonella and Yersinia spp. The work was limited to resistance in liquids with pH values 6–8. Results obtained under similar experimental conditions were sought. Thermal destruction lines for the various bacterial groups studied were constructed using log10 D values and treatment temperatures. There was a good linear relationship between log10 D and temperature with Escherichia coli, listerias and salmonellas. For campylobacters, enterococci and yersinias the relationships were weaker but, nevertheless, present. Using the slopes of the lines and their 95% confidence limits, z values and their 95% confidence limits were calculated. z values were compared with z values obtained from reports. The equations for the lines were also used for calculation of predicted means of D values at various treatment temperatures. 95% confidence limits on predicted means of D values and on predicted individual D values were also calculated. Lines and values are shown in figures and tables. Differences in heat resistance noted between and within the bacterial groups studied are discussed.

Sörqvist S

2003-03-01

407

Superdormant spores of Bacillus species have elevated wet-heat resistance and temperature requirements for heat activation.  

Science.gov (United States)

Purified superdormant spores of Bacillus cereus, B. megaterium, and B. subtilis isolated after optimal heat activation of dormant spores and subsequent germination with inosine, d-glucose, or l-valine, respectively, germinate very poorly with the original germinants used to remove dormant spores from spore populations, thus allowing isolation of the superdormant spores, and even with alternate germinants. However, these superdormant spores exhibited significant germination with the original or alternate germinants if the spores were heat activated at temperatures 8 to 15 degrees C higher than the optimal temperatures for the original dormant spores, although the levels of superdormant spore germination were not as great as those of dormant spores. Use of mixtures of original and alternate germinants lowered the heat activation temperature optima for both dormant and superdormant spores. The superdormant spores had higher wet-heat resistance and lower core water content than the original dormant spore populations, and the environment of dipicolinic acid in the core of superdormant spores as determined by Raman spectroscopy of individual spores differed from that in dormant spores. These results provide new information about the germination, heat activation optima, and wet-heat resistance of superdormant spores and the heterogeneity in these properties between individual members of dormant spore populations. PMID:19592590

Ghosh, Sonali; Zhang, Pengfei; Li, Yong-qing; Setlow, Peter

2009-09-01

408

Corrosion behavior of nickel-containing alloys in artificial sweat.  

Science.gov (United States)

The corrosion resistance of various nickel-containing alloys was measured in artificial sweat (perspiration) using the Tafel extrapolation method. It was found that Ni, CuNi 25 (coin alloy), NiAl (colored intermetallic compounds), WC + Ni (hard metal), white gold (jewelry alloy), FN42 and Nilo Alby K (controlled expansion alloys), and NiP (electroless nickel coating) are in an active state and dissolve readily in oxygenated artificial sweat. By contrast, austenitic stainless steels, TiC + Mo2C + Ni (hard metal), NiTi (shape-memory alloy), Hastelloy X (superalloy), Phydur (precipitation hardening alloy), PdNi and SnNi (nickel-containing coatings) are in a passive state but may pit under certain conditions. Cobalt, Cr, Ti, and some of their alloys were also investigated for the purpose of comparison. Cobalt and its alloys have poor corrosion resistance except for Stellite 20. Chromium and high-chromium ferritic stainless steels have a high pitting potential but the latter are susceptible to crevice corrosion. Ti has a pitting potential greater than 3 V. Comparison between the in vitro measurements of the corrosion rate of nickel-based alloys and the clinical observation of the occurrence of contact dermatitis is discussed. PMID:3403567

Randin, J P

1988-07-01

409

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

International Nuclear Information System (INIS)

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

1999-09-01

410

Rolling contact fatigue behavior of heat resistant bearing steels at high operational temperatures  

Energy Technology Data Exchange (ETDEWEB)

An approach was made to estimate the endurance limit in rolling contact fatigue in dependence of the operational conditions for the bearing steels M50 (AMS 6491), M50 NiL (AMS 6278) and the nitrogen-alloyed Cronidur 30 (AMS 5898) by investigating the changes in the residual stress profiles after 5 million cycles of overrolling. Real main shaft bearings with a pitch diameter of 168 mm have been tested. To simulate the heat generated in the turbine engines even under boundary operational conditions oil inlet temperatures between 80 and 210 C have been applied, the rotational speed has been varied between 2,500 and 14,000 r/min and the interference fit has been changed to produce different hoop stress levels.

Boehmer, H.J. [FAG OEM and Handel AG, Schweinfurt (Germany); Hirsch, T. [Inst. fuer Werkstofftechnik, Bremen (Germany). Physical Analysis Dept.; Streit, E. [FAG Aircraft/Super Precision Bearings GmbH, Schweinfurt (Germany)

1998-12-31

411

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

DEFF Research Database (Denmark)

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 Ã?-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.

Bojer, Martin Saxtorph; Hammerum, Anette M

2012-01-01

412

Rough turning of nickel base alloys with plasma heating  

Energy Technology Data Exchange (ETDEWEB)

To raise the productivity of machining parts of heat-resistant nickel base alloys the process of rough turning for these materials with plasma heating has been investigated. Air and nitrogen have been used as plasma-forming gases to ensure optimum heating temperature of 830-900 deg C. Due to a better workability of heated metal the productivity raises 4-6 times as much.

Klauch, D.N.; Oganesyan, M.Z.; Nikitin, S.D.; Al' shannikov, V.P.; Chujko, A.G.

1984-07-01

413

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

International Nuclear Information System (INIS)

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

1994-04-01

414

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

Energy Technology Data Exchange (ETDEWEB)

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

Hussain, N.; Shahid, K.A.; Rahman, S. (Pakistan Inst. of Nuclear Science and Technology, Islamabad (Pakistan)); Khan, I.H. (Univ. of the Punjab, Lahore (Pakistan))

1994-04-01

415

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2005-08-15

416

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

International Nuclear Information System (INIS)

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

2005-01-01

417

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