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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

Creep rupture properties of a nickel-base heat-resistant alloy Hastelloy XR under varying stress condition  

International Nuclear Information System (INIS)

A series of constant load and temperature creep rupture tests and varying stress creep rupture tests was carried out on a nickel-base heat-resistant alloy Hastelloy XR, which was developed for applications in the High-Temperature Engineering Test Reactor, at temperatures ranging from 850 to 1000 degC in order to examine the applicability of the conventional creep damage rules, i.e., the life fraction, the strain fraction and their mixed rules. Among these three criteria, the life fraction rule showed the best applicability. The good applicability of the rule was considered to result from the fact that the creep strength of Hastelloy XR was not strongly affected by the change of the chemical composition and/or the microstructure during exposure to the high-temperature simulated HTGR helium environment. In conclusion the life fraction rule is applicable in engineering design of high-temperature components made of Hastelloy XR. (author)

1992-01-01

3

Creep rupture properties of a nickel-base heat-resistant alloy Hastelloy XR under varying temperature/stress condition  

Energy Technology Data Exchange (ETDEWEB)

A series of constant temperature and load creep rupture tests and varying temperature and/or load creep rupture tests was carried out on a nickel-base heat-resistant alloy Hastelloy XR, which was developed for applications in the High-Temperature Engineering Test Reactor, at 850 to 1000degC in the simulated HTGR helium gas. This report describes the applicability of the conventional creep damage rules, i.e., the life fraction, the strain fraction and their mixed rules, to the alloy. The applicability was examined using the data under varying both temperature and load conditions as well as those, which were obtained in the previous work, under constant temperature and varying load conditions. The life fraction rule showed the best applicability of these three criteria. The good applicability of the rule was considered to show that the change of the chemical composition and/or the microstructure during exposure to the high-temperature simulated HTGR helium environment was not appreciable to affect the creep strength of Hastelloy XR. Though the life fraction rule under varying both temperature and load conditions is slightly less applicable than that under constant temperature and varying load conditions, it has been concluded that the rule is applicable in engineering design of high-temperature components made of Hastelloy XR. (author).

Tsuji, Hirokazu; Nakajima, Hajime [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Tanabe, Tatsuhiko; Nakasone, Yuji

1993-05-01

4

Creep rupture properties of a nickel-base heat-resistant alloy Hastelloy XR under varying temperature/stress condition  

International Nuclear Information System (INIS)

A series of constant temperature and load creep rupture tests and varying temperature and/or load creep rupture tests was carried out on a nickel-base heat-resistant alloy Hastelloy XR, which was developed for applications in the High-Temperature Engineering Test Reactor, at 850 to 1000degC in the simulated HTGR helium gas. This report describes the applicability of the conventional creep damage rules, i.e., the life fraction, the strain fraction and their mixed rules, to the alloy. The applicability was examined using the data under varying both temperature and load conditions as well as those, which were obtained in the previous work, under constant temperature and varying load conditions. The life fraction rule showed the best applicability of these three criteria. The good applicability of the rule was considered to show that the change of the chemical composition and/or the microstructure during exposure to the high-temperature simulated HTGR helium environment was not appreciable to affect the creep strength of Hastelloy XR. Though the life fraction rule under varying both temperature and load conditions is slightly less applicable than that under constant temperature and varying load conditions, it has been concluded that the rule is applicable in engineering design of high-temperature components made of Hastelloy XR. (author)

1993-01-01

5

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

International Nuclear Information System (INIS)

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

1993-01-01

6

Heat resistant sintered hard alloy  

Energy Technology Data Exchange (ETDEWEB)

A heat-resistant sintered hard alloy is described containing 35 to 95% by weight of a WCoB type complex boride containing chromium in a cobalt base alloy matrix phase, wherein said hard alloy consists of 1.5 to 4.1% by weight of boron, 19.1 to 69.7% by weight of tungsten, 1 to 25% by weight of chromium, the balance being cobalt, and a maximum of 1%, by weight of the alloy, of unavoidable impurities.

Takagi, Kenichi; Komai, Masao; Isobe, Yoshihiko.

1993-08-24

7

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

8

Filler metal development for Hastelloy alloy XR  

International Nuclear Information System (INIS)

[en] 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

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

10

Heat-resistant coatings on nickel alloys  

Energy Technology Data Exchange (ETDEWEB)

The authors search for heat-resistant coating containing Ni, Cr, W, Si, and Al with the forming temperature below 1300 degrees C. To decrease the forming temperature, carbon was introduced into the composition of the coating. It was established that the forming temperature of the coating depends on the composition of the alloy. The alloying elements, particularly Mo, W, and Ti, diffuse from the alloy into the coating and decrease its forming temperature.

Antonova, E.A.; Pustotina, S.R.; Romanov, A.Y.; Sinai, L.M.

1986-02-01

11

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

Science.gov (United States)

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

Narita, Toshio

2009-09-01

12

Oxidation rates of some heat resistant alloys  

Energy Technology Data Exchange (ETDEWEB)

Cyclic oxidation testing of several heat resistant alloys was carried out at 1,093 and 1,149 C for times up to 3,000 hours. The quantitative results, coupled with extensive service history for the established alloys, provide a useful guide to anticipated performance of newly developed grades. Maximum practical use temperature is to some extent a function of section size, thin sheet being more quickly depleted of elements used to form the protective scale. Metallurgical factors influencing oxidation rate include grain size as well as the alloying elements silicon, manganese, molybdenum and columbium. Some comparisons are made between laboratory results and service performance.

Kelly, J.C.; Wilson, J.D. [Rolled Alloys, Temperance, MI (United States)

1995-12-31

13

Comparative carburization of heat resistant alloys  

Energy Technology Data Exchange (ETDEWEB)

Two high strength, centrifugally cast heat resistant materials were examined under near identical pack carburizing conditions. The first material represented an alloy class which is becoming the most popular for replacement coils in ethylene pyrolysis furnaces due to its large improvement in carburization resistance over HP based alloys. The second material represented the next generation of alloys to be used for this purpose. Additionally, several investigative techniques were employed to illustrate some of the strengths and weaknesses of each technique. A recent advance in microscopy, the focused ion beam microscope (FIB), is highlighted as a possible alternative to the scanning electron microscope (SEM) and the electron probe microanalyzer (EPMA). The FIB microscope provided exceptional new possibilities for examining heat resistant alloys, primarily due to its ability to section samples in situ and its ability to examine uncoated insulating materials, both of which are difficult or impossible for electron microscopes. The next generation heat resistant material displayed remarkable carburization resistance. It was suggested that the improvement may have be due in part to its ability to form a dense Cr{sub 2}O{sub 3} oxide both internally and on the surface.

Mimer, R. [Kubota Metal Corp., Orillia, Ontario (Canada). Fahramet Div.; Phaneuf, M.W. [Fibics Inc., Ottawa, Ontario (Canada)

1998-12-31

14

Thermomechanical treatment of heat-resisting alloys  

International Nuclear Information System (INIS)

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

1980-01-01

15

Machining of high alloy steels and heat resistant alloys  

International Nuclear Information System (INIS)

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

2000-01-01

16

Argon-arc welding of heat resisting aluminium alloys  

International Nuclear Information System (INIS)

Welding of aluminium heat resisting alloys of the Al-Cu-Mg system is studied. The hot-shortness of heat-resistant alloys M40, 1150 and 1151 are at the level of aluminium alloys 1201 and by 2-3 times lower as compared to the aluminium alloy AMg6. The M40, 1150 and 1151 alloys have unquestionable advantages against other know aluminium alloys only at temperatures of welded structures operation, beginning with 150-2000 deg C and especially at 250 deg C

17

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

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)

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

1993-01-01

19

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 f alloy with boron carbide but there was no change on the yield strength. (author).

1980-01-01

20

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

International Nuclear Information System (INIS)

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

1982-01-01

 
 
 
 
21

Heat resistant magnesium alloys for automotive powertrain applications  

Energy Technology Data Exchange (ETDEWEB)

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

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

2003-07-01

22

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

23

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

24

Study of creep and rupture behavior for hastelloy alloy XR  

International Nuclear Information System (INIS)

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

1983-01-01

25

Metal Dusting of Heat-Resistant Alloys  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Metal dusting leads to disintegration of such alloys as iron and nickel-based into a “dust” of particulate metal, metal carbide, carbon, and/or oxide. It occurs in strongly carburising environments at 400-900°C. Literature survey has shown that alloys behave differently in metal dusting conditions b...

Al-Meshari, Abdulaziz I

26

Thermal fatigue strength of heat-resistant alloys  

Science.gov (United States)

Results obtained from exposure of nickel-based heat-resistant alloys to thermal fatigue tests carried out for several years are presented. A methodology of carrying out tests in vacuum is used, which makes it possible to observe incipience of microcracks and their propagation rate. Results obtained from a calculation of sample strain conditions are analyzed.

Getsov, L. B.; Rybnikov, A. I.; Semenov, A. S.

2009-05-01

27

Compatibility of heat resistant alloys with boron carbide, 5  

International Nuclear Information System (INIS)

[en] 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

28

Ductility improvement of heat resisting titanium alloys with hydrogen. [Alloy VT18U  

Energy Technology Data Exchange (ETDEWEB)

Ductility improvement of VT18U and VT3-1 heat resisting titanium alloys with hydrogen at high-temperature tensile tests is studied. It is shown that alloying of VT18U and VT3-1 heat resisting titanium alloys with hydrogen due to stabilization by dissolved hydrogen of ductile ..beta..-phase essentially decreases their deformation resistance under heat treatment in a wide range of deformation rates. Favourable effect of hydrogen on ductility and deformation resistance of titanium alloys permits to decrease hot deformation temperature by 80-100 deg with simultaneous decrease of deforming efforts. Decrease of hot deformation temperature of hydrogeneous titanium alloys without increase of deforming efforts improves force conditions of deforming instrument operation. Change of hot deformation temperature of hydrogeneous heat resisting titanium alloys permits to obtain microstructures with a wide spectrum of phase composition and phase morphology.

Nosov, V.K.; Kolachev, B.A.; Pavlov, E.I.

1982-12-01

29

Cyclic strength of heat-resistant alloys with coatings  

Energy Technology Data Exchange (ETDEWEB)

Methods for evaluating the cyclic strength of heat-resistant alloys with coatings are analyzed. It is shown that models for calculating thermal fatigue crack growth rates in the base metal based on the difference between the thermal expansion coefficients and elastic moduli of the base metal and the coating are not sufficiently accurate for practical applications since they do not allow for changes in the physicomechanical properties of the coating in the thickness direction. The characteristics of crack nucleation and growth in protective coatings associated with the structural inhomogeneity of the coating are examined with reference to Co(Ni)-Cr-Al-Y condensation coatings on EP539 and EP220 alloys. 8 references.

Getsov, L.B.; Rybnikov, A.I.; Malashenko, I.S.

1988-12-01

30

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

International Nuclear Information System (INIS)

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

1988-01-01

31

Flammability of selected heat resistant alloys in oxygen gas mixtures  

Energy Technology Data Exchange (ETDEWEB)

Within recent years, the use of oxygen has increased in applications where elevated temperatures and corrosion may be significant factors. In such situations, traditional alloys used in oxygen systems will not be adequate. Where alternative alloys must be utilized, based upon environmental requirements, it is essential that they may be characterized with respect to their ignition and combustion resistance in oxygen. Promoted ignition and promoted ignition-combustion are terms which have been used to describe a situation where a substance with low oxygen supports the combustion of a compatibility ignites and more ignition resistant material. In this paper, data will be presented on the promoted ignition-combustion behavior of selected heat resistant engineering alloys that may be considered for gaseous oxygen applications in severe environments. In this investigation, alloys have been evaluated via both flowing and static (fixed volume) approaches using a rod configuration. Oxygen-nitrogen gas mixtures with compositions ranging from approximately 40 to 99.7% oxygen at pressures of 3.55 to 34.6 MPa were used in the comparative studies.

Zawierucha, R.; McIlroy, K.; Million, J.F. [Praxair, Inc., Tonawanda, NY (United States)

1995-12-31

32

New heat resistant polymer alloy. Shin tainetsusei polymer alloy  

Energy Technology Data Exchange (ETDEWEB)

A concept of designing high heat resistant materials by taking out their potential crystallization faculties by mixture of different sorts of polymers is a new attractive subject for the future material design. This paper explains that the crystallization of 44I occurs by thermal treatment after adding noncrystal polyethersulfone (PES) to aramid 44I which has been regarded as a noncrystal polymer. It was found that this crystal could be a heat resistant material which does not soften even over 400 centigrade and keeps high elasticity. With this aramid-PES block copolymer, micro-phase separation did not occur. Also. single glass transition temperature was observed by the DSC measurement using a cost film, and simultaneously exothermic peak by crystallization around 330 centigrade was found. It is considered that the increase in crystallization speed with PES addition is due to a little lower glass transition temperature of PES than that of 44I and due to liquid-liquid phase separation. 3 refs., 3 figs.

Inoue, T.; Imai, Y. (Tokyo Inst. of Tech., Tokyo (Japan))

1990-07-01

33

Heat resistant alloys as interconnect materials of reduced temperature SOFCs  

Energy Technology Data Exchange (ETDEWEB)

Heat-resistant alloys, Haynes 230 and SS310, were exposed to air and humidified H{sub 2} at 750{sup o}C for up to 1000h, respectively, simulating the environments in reduced temperature solid oxide fuel cells (SOFCs). The oxidized samples were characterized by using SEM, EDS and X-ray diffraction to obtain the morphology, thickness, composition and crystal structure of the oxide scales. A mechanism for the formation of metallic Ni-rich nodules on top of the oxide scale in Haynes 230 sample oxidized in humidified H{sub 2} was established. Thermodynamic analysis confirmed that MnCr{sub 2}O{sub 4} is the favored spinel phase, together with Cr{sub 2}O{sub 3}, in the oxide scales. (author)

Jian, Li; Jian, Pu; Shunxu, Wang; Jianzhong, Xiao [School of Materials Science and Engineering, State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074 (China); Guangyuan, Xie [School of Materials Science and Metallurgical Engineering, Wuhan University of Science and Technology, Wuhan, Hubei 430080 (China)

2006-06-19

34

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1982-01-01

35

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

36

Effects of aging and test temperature on tensile and fatigue properties of nickel-base heat-resistant alloy  

International Nuclear Information System (INIS)

[en] A series of tensile and strain controlled low-cycle fatigue tests were conducted at the temperatures ranging from room temperature (RT) to 900 deg C on a nickel-base heat-resistant alloy, Hastelloy XR-II, which is one of the candidate alloys for applications in the process heating high-temperature gas-cooled reactor (HTGR). Materials were tested in the solution annealed as well as in the pre-aged condition where aging consisted of isothermal exposure at 900 deg C for the period of 1000 h. In those tests the effects of aging and test temperature on tensile and fatigue properties were investigated. The ductility minimum point was observed near 600 deg C in the solution annealed condition. On the other hand, the ductility of the aged materials was reduced excessively at RT, and increased with increasing test temperature. At and below 700 deg C, the fatigue lives of the aged materials were shorter than those of the solution annealed ones. The tendency was interpreted through the fractographic and metallographic features of the fatigued specimens. The fatigue lives estimated from tensile properties using the method proposed by Manson were compatible with the results of fatigue tests under the test conditions employed. (author)

1987-01-01

37

Mechanically alloyed Ni-base alloys for heat-resistant applications  

Energy Technology Data Exchange (ETDEWEB)

INCONEL alloys MA 754 and MA 758 are nickel-base oxide dispersion-strengthened (ODS) alloys made by mechanical alloying (MA). Commercial use of Ma Ni-base alloys to date has been predominantly in aerospace applications of alloy MA 754 as turbine engine vanes. Both alloys are suitable for industrial heat treating components and other heat resistant alloy applications. Field trials and commercial experience in such applications of MA alloys are being gained while high temperature property characterization and new product form development continue. Hot isostatic pressing (HIP) is the standard consolidation method for billets from which large bar and plate are produced for industrial applications of MA. This paper describes production of standard mill shapes from HIP billets, and it presents information on current and potential uses of MA alloys in applications such as: skid rails for use in high temperature walking beam furnaces, heat treating furnace components, components for handling molten glass, and furnace tubes. The paper includes comparison of the properties obtained in alloy MA 754 (20% Cr) and alloy MA 758 (30% Cr).

Wilson, R.K.; Fischer, J.J. [INCO Alloys International, Inc., Huntington, WV (United States)

1995-12-31

38

Phase composition of the diffusion layers of metallic coatings on heat-resistant nickel alloys  

Energy Technology Data Exchange (ETDEWEB)

Condensed and diffused heat-resistant Ni-Cr-Al-Y coatings are used to protect gas turbine blades from oxidation at high temperatures. Since theoretical models to predict the phase stability of the substrate-coating system do not exist, it is essential to investigate the mechanisms of compatibility between the coating material and the protected heat-resistant alloy. In this article Ni-Cr-Al-Y coatings with supplementary additions of tantalum are considered.

Kablov, E.N.; Morozova, G.I.; Matveeva, G.N. [and others

1995-05-01

39

Selection and Evaluation of Heat-Resistant Alloys for SOFC Interconnect Applications  

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. However, no specific criteria or inclusive study are available as a reference to help select and evaluate suitable candidates from the hundreds of available heat resistant alloy compositions, which overall demonstrate oxidation resistance at high temperatures. In this work, composition criteria have been proposed for pre-selection of heat resistant compositions, such as Ni-, Fe-, and Co-base superalloys, Cr-base alloys and stainless steels. The proposed criteria have been employed to establish a database of heat resistant alloys at PNNL, where a systematic approach has been initiated to evaluate and modify/develop metallic alloys for SOFC interconnect applications. The pre-selected compositions are further evaluated by referring our screening studies and published data. It appears that it would be very difficult for traditional alloys to fully satisfy the materials requirements for long-term operation at the intermediate temperature range of 700~850 degrees C. The applicability however can be improved through surface/bulk-modification and implementation of novel stack designs.

Yang, Z Gary; Weil, K. Scott; Paxton, Dean M.; Stevenson, Jeffry W.

2003-07-10

40

Design fatigue curve for Hastelloy-X  

International Nuclear Information System (INIS)

In the design of components intended for elevated temperature service as the experimental Very High-Temperature gas-cooled Reactor (VHTR), it is essential to prevent fatigue failure and creep-fatigue failure. The evaluation method which uses design fatigue curves is adopted in the design rules. This report discussed several aspects of these design fatigue curves for Hastelloy-X (-XR) which is considered for use as a heat-resistant alloy in the VHTR. Examination of fatigue data gathered by a literature search including unpublished data showed that Brinkman's equation is suitable for the design curve of Hastelloy-X (-XR), where total strain range ? epsilon sub(t) is used as independent variable and fatigue life Nsub(f) is transformed into log(log Nsub(f)). (author)

1983-01-01

 
 
 
 
41

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

Energy Technology Data Exchange (ETDEWEB)

A method of atomic absorption was developed. It allows for the tungsten to be determined in heat resistant 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.

Gregorczyk, S.; Wycislik, A. (Politechnika Slaska, Gliwice (Poland))

1980-01-01

42

Heat-resisting alloys for hard surfacing and sealing pad welding  

Directory of Open Access Journals (Sweden)

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

R.O. Wielgosz

2010-01-01

43

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

International Nuclear Information System (INIS)

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

1981-05-06

44

Geometrical product specifications heat-resistant cobalt cast alloy  

Directory of Open Access Journals (Sweden)

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

Lyubimov V.; Opiekun Z.; Bonk C.

2007-01-01

45

Thermal diffusivity of nickel base heat resisting intermetallic alloys  

International Nuclear Information System (INIS)

[en] Thermal diffusivity of ?- ?'- and ?-allloys of Ni-Al-Cr system has been investigated within the temperature range of 700 to 1200 K. Method of plane temperature waves excited by laser irradiation was used in experiments which were conducted in helium environment. Correlations have been revealed between thermal diffusivity and electric conductivity of these alloys

1993-01-01

46

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.

1993-01-01

47

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

International Nuclear Information System (INIS)

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

1983-01-01

48

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

International Nuclear Information System (INIS)

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

1978-01-01

49

The Properties of the Highly Heat-Resistant EP487 Alloy (Svoistva Vysokozharo Prochnogo Splava EP487), .  

Science.gov (United States)

The heat resistant properties of the EP487 (KhN60MBT10) alloy are investigated. The mechanical properties of specimens of this alloy are shown graphically and it is shown that an increase in the molybedenum content in the alloy by specified amounts raises...

V. K. Tsvetkova V. N. Zhugin V. V. Topelin A. P. Boyarinova V. P. Stepanov

1970-01-01

50

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

International Nuclear Information System (INIS)

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

1982-01-01

51

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

Energy Technology Data Exchange (ETDEWEB)

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

Inouye, H.; Rittenhouse, P.L.

1981-01-01

52

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.

1994-01-01

53

Temperature-force dependence of activation energy for heat-resistant alloys cyclic creep  

Energy Technology Data Exchange (ETDEWEB)

Activation energy of the cyclic creep process for heat-resistant nickel alloys at high-temperature (Tsub(isp) approximately equal to 0.5-0.8 Tsub(pl)) low-cyclic (f approximately equal to 35 Hz) loading is determined on the basis of the experimental data processing results in the range of deformation rates from 10/sup -3/ to 10/sup 1/ %/h. It is stated that activation energy of the cyclic creep is practically independent of the cycle stresses and temperature and that the stresses of the asymmetric cycle affect the creep rate mainly through changes in the frequency factor.

Golub, V.P. (AN Ukrainskoj SSR, Kiev. Inst. Mekhaniki)

1982-11-01

54

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

International Nuclear Information System (INIS)

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

1994-01-01

55

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 m...

Ohnuma I.; Kainuma R.; Ishida K.

56

High-temperature tensile-hold crack-growth behavior of HASTELLOY® X alloy compared to HAYNES® 188 and HAYNES® 230® alloys  

Science.gov (United States)

The creep-fatigue crack-growth tests of HASTELLOY® X alloy were carried out at the temperatures of 649°C, 816°C, and 927°C in laboratory air. The experiments were conducted under a constant stress-intensity-factor-range (? K) control mode with a R-ratio of 0.05. In the constant ? K tests, a ? K of 27.5 MPa sqrt{m} and a triangular waveform with a frequency of 0.333 Hz were used. Various tensile hold times at the maximum load were imposed to study fatigue and creep-fatigue interactions. Crack lengths were measured by a direct current potential drop method. In this paper, effects of hold time and temperature on the crack-growth rates are discussed. Furthermore, the crack-growth rates of the HASTELLOY® X alloy are compared to those of the HAYNES® 188 and HAYNES® 230® superalloys.

Lee, S. Y.; Lu, Y. L.; Liaw, P. K.; Choo, H.; Thompson, S. A.; Blust, J. W.; Browning, P. F.; Bhattacharya, A. K.; Aurrecoechea, J. M.; Klarstrom, D. L.

2008-03-01

57

Creep behavior for Hastelloy-XR  

International Nuclear Information System (INIS)

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

1988-01-01

58

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Lystrup, Aage; Rittenhouse, P. L.; DiStefano, J. R.

59

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

International Nuclear Information System (INIS)

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

1977-01-01

60

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)

[en] 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

 
 
 
 
61

On the development of heat resisting alloys for application to a very high temperature helium-cooled reactor  

International Nuclear Information System (INIS)

The status of the research on heat resisting alloys for very high temperature nuclear process heat applications is reviewed. Special test methods and apparatus have been developed and used in the studies in which the materials are tested at temperatures 800 to 10000C. The results have been reflected to the development of superalloys tailored for the helium cooled reactor applications. The subjects covered are alloy development, test methods, helium-cycle fatigue, ageing embrittlement, neutron irradiation effects and the radioactivity release. (author)

1983-01-01

62

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

63

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

64

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

65

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

International Nuclear Information System (INIS)

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.).

1991-01-01

66

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

67

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

International Nuclear Information System (INIS)

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

1994-01-01

68

Experimental evaluation of the characteristics of super-heat-resisting Nb-based and Mo-based alloys  

Energy Technology Data Exchange (ETDEWEB)

Both the Nb-based and Mo-based alloys have been designed and developed in order to establish the frontier technique for super-heat-resisting materials used in the liquid alkali metal environment at high temperatures. In this study, mechanical properties of the designed Nb-1Hf alloy were experimentally evaluated. In addition, the brittleness of Nb-based alloys observed at 1073K were discussed. Moreover, characteristics of both the designed Nb-based and the Mo-based alloys were summarized in a consistent way. The tensile strength of the designed Nb-1Hf alloy was slightly lower at room temperature than that of the commercial Nb-1Zr alloy. But, the designed alloy was superior in high temperature creep properties to any other solid solution hardened Nb-based alloys. In addition, the modulated structure was observed in the brittle specimen crept at 1073K, but not in the ductile specimen crept at 1273K. Therefore, it caused probably the brittleness of the Nb-1Zr alloy at 1073K. It was concluded that all the designed Nb-1Hf, Mo-15Re-0.1Zr and Mo-15Re-0.1Zr-0.1Ti alloys had an excellent total balance in the tensile and creep properties at high temperatures, corrosion resistance to liquid Li and cold-workability, compared to other experimental and commercial alloys. (J.P.N.)

Morinaga, Masahiko; Oda, Masaaki; Yamauchi, Takashi [Nagoya Univ. (Japan). School of Engineering

1998-03-01

69

Effect of oxide film of heat resistant alloy on coke formation during naphtha pyrolysis  

International Nuclear Information System (INIS)

The coking of cracking furnace tubes has been an important subject of ethylene plants. The coke formations rate on the heat resistant alloys of 20Cr-4.5Al-0.5Y2O3 covered with Al2O3 oxide film and 25Cr-35Ni covered with Cr2O3 oxide film during the thermal cracking of naphtha was quantitatively evaluated at temperatures ranging from 810 to 930 .deg. C. The experimental results showed that the coke formation rate on 20Cr-4.5Al-0.5Y2O3 was lower than that on 25Cr-35Ni because of the difference of a catalytic activity to coke formation, especially in the case of a pre-carburized condition. Namely, the Al2O3 formed on 20Cr-4.5Al-0.5Y2O3 was stable even after carburization treatment and inert for catalytic coke formation, while coke formation on 25Cr-35Ni was under the control of catalytic coke formation, and carburization of 25Cr-35Ni accelerated catalytic coke formation. The stability of Al2O3 and Cr2O3 in a hydrocarbon with steam environment was thermodynamically calculated in 0.1mol of steam, 0.2mol of ethylene and 0.1mol of methane at 1,100 .deg. C. The simulation result shows that Al2O3 is exceedingly stable while Cr2O3 could be decomposed partially into chromium carbide. Therefore, it is concluded that Al2O3 on 20Cr-4.5Al-0.5Y2O3 is more stable than Cr2O3 on 25Cr-35Ni, and 20Cr-4.5Al-0.5Y2O3 is more resistant to coke formation and carburization than 25Cr-35Ni in a hydrocarbon with steam environment at high temperature

2002-01-01

70

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

International Nuclear Information System (INIS)

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

1985-01-01

71

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

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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.; Kainuma R.; Ishida K.

2012-01-01

72

The behavior of boron and carbon in the failure zone of a heat resistant granular nickel alloy  

Energy Technology Data Exchange (ETDEWEB)

The behavior of boron and carbon in the failure zone of a heat-resistant compact granular nickel alloy Ni-5Al-2Ti-9Cr-15Co-6W-4Mo-3Nb was investigated by conducting mechanical tension tests at temperatures between 800-1150 C and examining the distribution of B and C in the failure zone. It is found that the structural-chemical stability of boron in the failure zone is significantly greater than that of carbon, leading to an increased migration of boron in the critical-crack region. The mechanisms involved in the differential migration of the two elements during tensile tests are discussed. 10 refs.

Shul' ga, A.V.; Kuz' micheva, L.G.; Vaulin, D.D.; Podol' skij, M.S.

1992-12-01

73

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

International Nuclear Information System (INIS)

[en] 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

74

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

Energy Technology Data Exchange (ETDEWEB)

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 of 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.

Nagato, Kotaro; Satoh, Keisuke; Murakami, Takashi (Kawasaki Heavy Industries Ltd., Kobe (Japan))

1983-07-01

75

X-ray fluorescence analysis of nickel-base heat-resisting alloys using fundamental parameter method  

International Nuclear Information System (INIS)

The fundamental parameter (FP)-XRF analysis of ten alloying elements (Al, Ti, Cr, Mn, Fe, Co, Zr, Nb, Mo and W) in nickel-base heat-resisting alloys was performed with the XRF-11 program. One nickel-base alloy for multi-elements calibration standard was prepared by a vacuum are melting method. The homogeneity test of alloying elements in the disk standard was performed by spark emission spectrochemical analysis. Consequently, the standard could be used for the FP-XRF analysis calibration. The chemical composition of the calibration standard was determined by the wet chemical analyses and inductively coupled plasma atomic emission spectrometry after ion-exchange separation. The spectral line overlaps, that is, mMn,Cr, mCo,Fe, mNb,Mo and mMo,Zr were 0.0004, 0.0003, 0.0004 and 0.0030, respectively. The accuracies for the determination of alloying elements with the proposed method obtained from fifteen standard reference materials were almost equal to those obtained by the correction method using theoretical alpha coefficients. The relative standard deviations (RSD) of repetitive seven measurements for the analytical values of the ten alloying elements were within about 1.5% with the exception of those for manganese (Mn; 0.01%, RSD; 6.08%) and tungsten (W; 0.06%, RSD; 6.69%). (author)

1990-01-01

76

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

International Nuclear Information System (INIS)

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

2011-01-01

77

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

78

Creep strength of Hastelloy XR welded joints  

Energy Technology Data Exchange (ETDEWEB)

Creep (rupture) tests have been carried out at 950degC in the air environment for base metal, welded joint and weld metal specimens of Hastelloy XR, which is a Ni base heat resistant alloy and is employed as a high temperature material of the intermediate heat exchanger and piping liners for the High Temperature Engineering Test Reactor (HTTR). The weld metal contained some amount of boron. The following results were clarified: 1) Stress rupture strengths of welded joints were equivalent to that of base metal in the short time duration but lower than that after about 1000h those of base metal. The reason can be attributed to boron diffusion from weld metal to base metal due to concentration gradient. 2) The stress rupture strength of weld metal was slightly higher than that of the base metal. However, it has an inclination of drop the straight line after 2000h. This is also explained by the effect of boron diffusion. Regarding the difference due to the orientation of weld metal, the transverse strength to the weld bead was slightly higher than the longitudinal strength. The creep elongation to the lateral direction was clearly larger than that to the longitudinal direction. 3) High temperature pre-aging was observed to have detrimental effect in the welded joints, but it was not observed in the weld metal. This can be explained by the estimation that boron diffusion in the weld metal specimen was very small because of no concentration gradient. (author)

Tachibana, Katsumi; Nishi, Hiroshi; Eto, Motokuni [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Muto, Yasushi

1999-03-01

79

Oxidation resistance of eight heat-resistant alloys at 870, 980, 1,095, and 1,150 C  

Energy Technology Data Exchange (ETDEWEB)

Oxidation testing of heat-resistant alloys is described. The testing procedure utilized weight-gain measurements using one specimen, which was withdrawn and weighted at intervals of 1 week, for 10-18 weeks. The specimen was placed in a porcelain cup during exposure and covered upon cooling to retain spalled oxide. Weight gain was used to determine the kinetics of oxidation and was extrapolated to 3,000 hr. The specimen was withdrawn at the end of the exposure, weighed, cathodically descaled, and reweighed. The ratio of oxygen ions to metal ions was determined for each alloy and test temperature. This ratio approaches the stoichiometric ratio for Fe{sub 3}O{sub 4} or Cr{sub 2}O{sub 3}. The ratio for each test is used to convert weight gain to weight loss. The amount of adherent oxide was determined as well as the total amount of oxide, leading to an expression for oxide adherency. The oxidation resistance of Fe-Cr-Ni alloys increased with increasing Cr and Ni, with Cr being the most critical element. Additions of Si, Al, or Ce were shown to extend the usefulness of Fe-Cr-Ni alloys.

Rundell, G.; McConnell, J. (Rolled Alloys, Temperance, MI (United States))

1991-10-01

80

Mechanism of scandium influence on strength and heat resistance increase in Al-Mg alloys  

Energy Technology Data Exchange (ETDEWEB)

An attempt is made to study the strengthening nature in the Al-Mg-Sc alloy system. The problems of the temperature stability of the non-crystallized structure of the Al-6.5% Ng alloy and the nature of secondary extractions in these alloys caused by scandium presence, are studied. The alteration of the fluidity limit of the Al-6.5% Mg-Se alloys depending on the annealing temperature for various types of intermediate products is shown. Doping of the Al-6.5% Mg alloy with scandium brings about a considerable increase of strength properties, as a result of formation of the ScAl/sub 3/ phase.

Drits, M.E.; Pavlenko, S.G.; Toropova, L.S.; Bykov' , Yu.G.; Ber, L.B. (AN SSSR, Moscow. Inst. Metallurgii)

1981-01-01

 
 
 
 
81

Influence of structure of heat-resistant nickel alloy ZhS6U on its weldability in the solid state  

Energy Technology Data Exchange (ETDEWEB)

A study was made of the influence of various structural characteristics of heat-resistant alloys and the phenomenon of superplasticity on the formation of a welded joint by diffusion welding. Studies were performed on heat resistant alloy ZhS6U in the cast state and the same alloy obtained from granules by powder metallurgy. Tests were performed in the 960-1200/sup 0/C temperature interval at deformation rates of 1 x 10/sup -4/ - 1 x 10/sup -1/ S/sup -1/ and showed significant differences in mechanical properties of the alloys obtained by different methods, related to the structural state of the alloy. The cast alloy has low ductility and high resistance to plastic deformation, whereas the powder metallurgy product shows all the signs of superplasticity at 1050-1150/sup 0/C. The structure formed upon heating to the welding point has decisive influence on the weldability of heat-resistant nickel alloys. The best-quality welded joint is obtained under temperature and speed conditions corresponding to the range of superplastic deformation of the alloy.

Golubev, V.N.; Sharif' yanov, F.Sh.; Vlasova, A.V.

1985-02-01

82

Investigation into the causes of early fracture in heat resisting alloys  

International Nuclear Information System (INIS)

Temperature regions of the existence of the main strengthening ?-Ni3Ti phase and Laves phase based on Fe2Mo compound in an iron-nickel VZh102 alloy are determing using physicochemical phase analysis method. It is ascertained that under a high content of Laves phase brittle fracture of alloy occurs. It is proposed to correct the VZh102 alloy phase composition using the reduction thermal treatment.

1992-01-01

83

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)

[en] 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

84

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

International Nuclear Information System (INIS)

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

1996-01-01

85

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

International Nuclear Information System (INIS)

[en] Mechanical property and Microstructural changes of Ni-base super alloys after aging with and without tensile stress were observed in the temperature range of 500-10000C 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

86

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

International Nuclear Information System (INIS)

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

1982-01-01

87

Influence of granule metallurgy stages on boron distribution in heat resisting nickel granular alloy  

International Nuclear Information System (INIS)

Methods of autoradiography, metallography and X-ray spectrum microanalysis were applied to study boron distribution throughout the structural constituents of granular nickel base alloy (Ni-9%Cr-16%Co-5%Al-7%W-2%Ti-Nb-Hf-C-B) at various stages of granule technology. The regularities of boron distribution are determined for compacts produced from granules of centrifugal and gas jet spraying. The mechanism of formation of granules with anomalously high boron concentration is proposed. A consideration is given to the phenomenon of boron migration to grain boundaries at heat treatment. 10 refs.; 4 figs.

1996-01-01

88

?????-?????????? ?????????? ???????????? ???????? ?? ???????? ??????? ??? ?? ??????????? ????????? ??????? Ion-plasma technology of deposition heat-resistant coatings for GTE turbine blades from resistant nickel alloys  

Directory of Open Access Journals (Sweden)

Full Text Available ??????????????? ??????????? ????????? ??????????? ??????????? ???????? ? ?????????????? ??????????, ?????????? ?? ???????????????????? ?????-??????????????? ? ?????-?????????? ??????? ???????-??????????? ????????? ? ????????? ????????. ?????????? ?????????? ???????????? ????????????? ? ??????? ???????????? ??????? ?? ????????? ??????????? ???????.The possibility of obtaining heat-resistant coatings using “nano-technology” based on high-energy ion-implantation and ion-plasma methods, protective and strengthening treatment and coating. The results of the study the heat resistance and fatigue strength of parts made of nickel-base superalloys.

?. ?. ???????; ?. ?. ????????; ?. ?. ????????; ?. ?. ?????????; ?. ?. ?????????

2012-01-01

89

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; Wang Yuqing; Yu Huashun

2009-01-01

90

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

91

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

Science.gov (United States)

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

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

2013-07-01

92

Effect of heat treatment temperature on creep properties of Hastelloy XR  

International Nuclear Information System (INIS)

[en] 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

93

Creep curve formularization at 950degC for Hastelloy XR  

International Nuclear Information System (INIS)

[en] Creep tests under constant stress were conducted on a nickel-base heat-resistant alloy, Hastelloy XR, in air at 950degC. Minimum creep strain rate, time to the onset of tertiary creep and time to rupture were obtained as a function of applied stress. Then, a creep constitutive equation was made based on the Garofalo formula for primary and secondary creep and based on the Kachanov-Rabotnov formula for tertiary creep, which could represent fairly well the experimental creep deformation curves under the constant stress conditions. The creep deformation under the constant load condition corresponding to the stress increment was analysed using the creep constitutive equation and strain hardening law. Then the calculated creep strain showed slightly higher value than the experimental creep strain, and the calculated life was shorter than the experimental one. (author)

1991-01-01

94

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

International Nuclear Information System (INIS)

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

1978-11-25

95

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.).

1993-01-01

96

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

Directory of Open Access Journals (Sweden)

Full Text Available Zr(OH)4 particle can be formed and negatively charged in alkaline solution with K2ZrF6 addition. Based on this mechanism, Zr-containing ceramic coatings were fabricated on LY12 aluminum alloy by microarc oxidation (MAO) using K2ZrF6 as a special additive in Na2SiO3-KOH base electrolyte. The modulation effects of K2ZrF6 addition on micro-microstructure, element distribution and phase composition were analyzed by SEM, EDS and XRD, respectively. Heat resistance of MAO coatings formed on LY12 aluminum alloy in different electrolyte was investigated. The results show that the K2ZrF6 addition can increase the micro-arc oxidation rate and significantly alter the structure of MAO coatings. Both the top surface and inner surface of MAO coatings fabricated in Zr-containing electrolyte become relatively smooth. Compared with the coating formed in Zr-free electrolyte, a large amount of Zr element is found in the coating formed in electrolyte with K2ZrF6 addition. Two main phases, ?-Al2O3 and ?-Al2O3, are contained in Zr-free coating. In contrast, more amorphous phase is found in Zr-containing coating with reduced amount of crystalline alumina. Experimental results also demonstrate that Zr-containing coating exhibits higher heat resistance.

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

2010-01-01

97

Recent welding techniques for heat resistant materials  

Energy Technology Data Exchange (ETDEWEB)

The performance required for recent heat resistant equipment has become diverse and severe. Therefore, advanced materials have been actively researched, and some of them are put into practical use. Also in the field of the welding techniques for heat resistant materials, the techniques aiming at the high quality of welded parts have been developed. In this report, typical heat resistant Ni base superalloys and their composition are shown. The heat resistant Ni base superalloys are classified into solid solution-strengthened alloys, precipitation-strengthened alloys, particle dispersion-strengthened alloys, crystal control alloys and sintered alloys. The main strengthening phase of the heat resistant Ni base superalloys is ..gamma..' phase. The strengthening mechanism due to dispersed particles functions at high temperature at which precipitation strengthening cannot be expected. Usually, welding is applied to solid solution-strengthened and precipitation-strengthened alloys, but in the case of particle dispersion-strengthened alloys and crystal control alloys, the properties of the parent materials are remarkably impaired by welding. The problems in the welding of these alloys are high temperature cracking in welding and reheat cracking in heat treatment. As the joining techniques for these alloys, TIG welding, electron beam welding, brazing, diffusion joining, liquid phase diffusion joining, and friction welding are described.

Nakao, Yoshikuni (Osaka Univ., Suita (Japan). Faculty of Engineering)

1984-08-01

98

Recent welding techniques for heat resistant materials  

International Nuclear Information System (INIS)

The performance required for recent heat resistant equipment has become diverse and severe. Therefore, advanced materials have been actively researched, and some of them are put in practical use. Also in the field of the welding techniques for heat resistant materials, the techniques aiming at the high quality of welded parts have been developed. In this report, typical heat resistant Ni base superalloys and their composition are shown. The heat resistant Ni base superalloys are classified into solid solution-strengthened alloys, precipitation-strengthened alloys, particle disperision-strengthened alloys, crystal control alloys and sintered alloys. The main strengthening phase of the heat resistant Ni base superalloys is ?' phase. The strengthening mechanism due to dispersed particles functions at high temperature at which precipitation strengthening cannot be expected. Usually, welding is applied to solid solution-strengthened and precipitation-strengthened alloys, but in the case of particle dispersion-strengthened alloys and crystal control alloys, the properties of the parent materials are remarkably impaired by welding. The problems in the welding of these alloys are high temperature cracking in welding and reheat cracking in heat treatment. As the joining techniques for these alloys, TIG welding, electron beam welding, brazing, diffusion joining, liquid phase diffusion joining and friction welding are described. (Kako, I.)

1984-01-01

99

Thermal fatigue of a heat-resistant Fe-0.45C-26Cr-33Ni-2Si-2Nb alloy  

Science.gov (United States)

The thermal fatigue of a heat-resistant Fe-0.45C-26Cr-33Ni-2Si-2Nb alloy is studied during thermal cycling in the temperature range 50-900°C up to 1000 cycles. The alloy is investigated in the initial as-cast state and after isothermal annealing during 1000 h at a temperature of 800, 900, 1000, or 1100°C; these conditions imitate the temperature conditions of operation and the structural state of various layers in a reaction pipe in the radiant furnace coils of ethylene production installations. After isothermal annealing, the thermal fatigue life of the alloy is found to decrease by a factor of 1.7-1.2 as compared to the initial as-cast state. It is shown that isothermal annealing and subsequent thermal cycling lead to the formation of carbide precipitates of various sizes in the alloy structure that affect the thermal fatigue life of the alloy. Thermal fatigue cracks are shown to form and grow predominantly at the sites of accumulation of fine carbide precipitates. Coarse (>10 ?m) precipitates retard crack growth, and cracks branch near such precipitates.

Oryshchenko, A. S.; Utkin, Yu. A.; Belyaeva, L. A.; Potapova, V. A.; Balakin, S. M.

2011-03-01

100

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

 
 
 
 
101

The structure and magnetic properties of a heat-resistant nickel-base alloy after a high-temperature deformation  

Science.gov (United States)

The structure of a turbine blade made of the ChS-70V alloy has been studied after operation in an experimental regime at 880°C. A considerable change in the structural state of the alloy indicates the presence of an extremely high level of stresses in the material. During the operation, the magnetic susceptibility of the alloy increases by two orders of magnitude. The possible structure objects responsible for a change in the magnetic susceptibility are the complexes of superstructure intrinsic stacking faults inside the intermetallic phase.

Stepanova, N. N.; Davydov, D. I.; Nichipuruk, A. P.; Rigmant, M. B.; Kazantseva, N. V.; Vinogradova, N. I.; Pirogov, A. N.; Romanov, E. P.

2011-09-01

102

Influence of ?-phase on properties of heat resistant wrought nickel alloy type KhN60KVYuMB  

International Nuclear Information System (INIS)

[en] Investigation into the structure and mechanical properties (impact strength, long-term strength, fatigue and plastic limits) of extruded bars of KhN60KVYuMB alloy designed for operation at high temperatures (700-800 deg C) is conducted. Microstructural investigations have shown that ?-phase, precipitating under isothermal ageing, does not spoil the alloy properties. 6 refs.; 5 figs.; 6 tabs

1995-01-01

103

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1983-07-01

104

Monotonous and cyclic creep in a heat-resistant 16Cr-10W-4Mo-TiAl nickel-based alloy - transmission electron microscopy study of microstructure  

Energy Technology Data Exchange (ETDEWEB)

A transmission electron microscopy (TEM) study of the dislocation structure developed in a nickel-based 16Cr-10W-4Mo-TiAl heat-resistant alloy was performed. Specimens subjected to monotonic or cyclic creep at 1023 K were investigated. Two distinctly different arrangements of dislocations were found after monotonic creep. At low applied stresses, numerous dislocation loops around {gamma}` particles indicate that the motion of dislocations is strongly influenced by {gamma}` precipitates. In the range of high applied stresses, pronounced slip bands form which are composed of several closely spaced {l_brace}111 slip planes. The cutting of {gamma}` particles by dislocations is observed frequently and the dislocation motion does not seem to be considerably hindered by precipitates. The distribution of dislocations after cyclic creep can be characterized as a mixture of the dislocation structures representative of low and high applied stress regions in monotonic creep. Two different dislocation arrangements are discussed in terms of the creep mechanism and the response of the alloy to cyclic creep loading. (orig.)

Dlouhy, A. [Czech Acad. of Sci., Brno (Czech Republic). Inst. of Phys. Mater.; Sustek, V. [Czech Acad. of Sci., Brno (Czech Republic). Inst. of Phys. Mater.; Cadek, J. [Czech Acad. of Sci., Brno (Czech Republic). Inst. of Phys. Mater.; Pahutova, M. [Czech Acad. of Sci., Brno (Czech Republic). Inst. of Phys. Mater.

1996-01-01

105

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

106

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

International Nuclear Information System (INIS)

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

1981-01-01

107

Cracking behaviour of heat-resisting steels, alloys and a carbon-fibre-reinforced polymer at elevated temperatures  

Energy Technology Data Exchange (ETDEWEB)

Characterization of creep-dominated fatigue cracking or cavitation in smooth specimens of a type 304 stainless steel is emphasized in terms of the stochastic nature of small-crack initiation and growth. As compared with monometallic ductile steels, a somewhat different cracking behaviour is shown for a titanium alloy Ti-17, an oxide-dispersion-strengthened nickel-base superalloy Inconel MA754 and a grey cast iron FC25. The mechanical behaviour of the large-crack propagation of creep and high temperature fatigue in high strength, low ductility materials is discussed in comparison with ductile materials. A quasi-small-scale creep condition dominates for the creep-fatigue crack propagation of the nickel-base superalloy Inconel 718, and a pure small-scale creep condition is established in the creep crack propagation of an aluminium alloy 2014-T6 and a carbon-fibre-reinforced polymer, namely unidirectional carbon fibres-poly (ether-ether-ketone) composite.

Ohtani, Ryuichi; Kitamura, Takayuki; Tada, Naoya (Dept. of Engineering Science, Kyoto Univ., Yoshida (Japan))

1991-09-15

108

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

109

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

International Nuclear Information System (INIS)

[en] 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

110

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

International Nuclear Information System (INIS)

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

1979-01-01

111

Time-dependent high-temperature low-cycle fatigue behavior of nickel-base heat-resistant alloys for HTGR  

International Nuclear Information System (INIS)

A series of strain controlled low-cycle fatigue tests at 900 deg C in the simulated HTGR helium environment were conducted on Hastelloy X and its modified version, Hastelloy XR in order to examine time-dependent high-temperature low-cycle fatigue behavior. In the tests with the symmetric triangular strain waveform, decreasing the strain rate led to notable reductions in the fatigue life. In the tests with the trapezoidal strain waveform with different holding types, the fatigue life was found to be reduced most effectively in tensile hold-time experiments. Based on the observations of the crack morphology the strain holding in the compressive side was suggested to play the role of suppressing the initiation and the growth of internal cracks or cavities, and to cause crack branching. When the frequency modified fatigue life method and/or the prediction of life by use of the ductility were applied, both the data obtained with the symmetric triangular strain waveform and those with the tensile hold-time experiments lay on the straight line plots. The data, however, obtained with the compressive and/or both hold-time experiments could not be handled satisfactorily by those methods. When the cumulative damage rule was applied, it was found that the reliability of HTGR components was ensured by limiting the creep-fatigue damage fraction within the value of 1. (author)

1988-01-01

112

Effects of oxidation on the impact energy of Hastelloy S and Hastelloy C-4 Charpy V-notch specimens heated in air at 600 to 800  

Energy Technology Data Exchange (ETDEWEB)

The /sup 90/SrF/sub 2/ heat source being developed at PNL utilizes a Hastelloy S or Hastelloy C-4 outer capsule having a 0.5-in.-thick wall to contain the Hastelloy C-276 inner capsule. The primary objective of the study was to demonstrate that the air oxidation of the outer capsule that could occur during heat-source service would not degrade the ductility and Charpy impact strength of the capsule below the licensing requirements given in Section 1.1. The /sup 90/SrF/sub 2/ heat source under development is intended for general-purpose use. Compatibility considerations limit the interface temperature between the /sup 90/SrF/sub 2/ and Hastelloy C-276 inner capsule to a maximum of 800/sup 0/C. The outer capsule surface temperature will be somewhat less than 800/sup 0/C, and depending on the service, may be substantially lower. The oxidation tests were therefore carried out at 600/sup 0/ to 800/sup 0/C for exposures up to 10,000h to cover the range of temperature the outer capsule might expect to encounter in service. The results showed that the oxidation of Hastelloy S and Hastelloy C-4 in air at 600/sup 0/ to 800/sup 0/C is very slow, and both alloys form adherent oxide layers that serve to protect the underlying metal. Subsurface attack of Hastelloy S and Hastelloy C-4 due to oxidation was greater than expected, considering the slow oxidation rates of the two alloys at 600/sup 0/ to 800/sup 0/C. Estimates of subsurface attack, determined from micrographs of the oxidized specimens, showed erratic results and it was impossible to assign any type of rate equation to the subsurface attack. A conservative estimate of long-term effects can be made using a linear extrapolation of the test results. There were no significant differences between the room-temperature Charpy impact energy of Hastelloy S and Hastelloy C-4 specimens oxidized in air at 600/sup 0/ to 800/sup 0/C and control specimens heated in vacuum.

Fullam, H.T.

1981-01-01

113

Influence of lanthanum, titanium and niobium on heat resistance of a chromium-nickel alloy in air and mazut ash environment  

International Nuclear Information System (INIS)

Influence of lanthanum, titanium and niobium on oxidation kinetics, composition and structure was investigated for oxide films forming in the 40Ni-60Cr alloy at 800-1000 deg C in air during 100-1000h and in mazut ash environment during 500h. It is shown that alloying the 40Ni-60Cr alloy with small additions (

1982-01-01

114

Application of Hastelloy X in gas-cooled reactor systems  

International Nuclear Information System (INIS)

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

1976-01-01

115

Heat resistant epoxy resin composition.  

UK PubMed Central (United Kingdom)

Heat-resistant epoxy resin composition obtained by incorporation of 2-(4-hydroxyphenyl)-2-(4-maleimidophenyl)propane in a resin composition consisting essentially of epoxy resin and an epoxy hardener is disclosed.

KITAHARA MIKIO; MACHIDA KOICHI; KUBO TAKAYUKI; TORIKAI MOTOYUKI; ASAHINA KOUTAROU; TANABE YOSHIMITSU; YAMAGUCHI KEIZABURO; YAMAGUCHI AKIHIRO

116

Corrosion of nickel alloys in nuclear fuel reprocessing  

International Nuclear Information System (INIS)

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

1975-04-14

117

Microstructures and creep behavior of as-cast and annealed heat-resistant Mg–4Al–2Sr–1Ca alloy  

International Nuclear Information System (INIS)

Highlights: ? Determining the intermetallics of the Mg–4Al–2Sr–1Ca alloy in as-cast and as-annealed state. ? Grain boundary phases play an important role during creep. ? The combination of dislocation motion and grain boundary sliding contributes to the creep deformation at high temperature. - Abstract: Microstructures, mechanical and creep properties of Mg–4Al–2Sr–1Ca alloy were investigated. As-cast microstructure of the experimental alloy consists of dendritic ?-Mg and grain boundary intermetallics, predominantly lamellar eutectic C14–Mg2Ca and bulky Mg–Al–Sr ternary phase. In addition, small amounts of C36–(Mg, Al)2Ca and Mg17Sr2 phases were also observed. Annealing at 400 °C leads to the transformation of Laves phases from C14 (or C14 + C36) to C15. Meanwhile, the lamellar eutectic tends to be spheroidised and the continuous intermetallic network is broken up with prolongation of annealing time. The as-cast alloy shows a very high creep resistance at the temperatures between 150 and 200 °C and applied stresses between 50 and 80 MPa. Annealing at 400 °C results in a remarkable decrease of creep properties due to the morphological modification of the grain boundary intermetallics. It is proposed that both dislocation motion and grain boundary sliding contribute to the creep deformation of the present alloy.

2012-01-01

118

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

119

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

International Nuclear Information System (INIS)

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

2001-01-01

120

Plastics with improved heat resistance  

Energy Technology Data Exchange (ETDEWEB)

In the past few years, new heat-resistant plastics have found worldwide development and considerably increased the fields of application of common thermally stable chemical materials. The scale of the heat-resistant plastics discussed here extends from polyimide materials for temperature up to 370/sup 0/C to thermostable polypropylene for permanent operation at 150/sup 0/C. The manufacture costs depend on the indivudual catagories of material and vary. Whilst the heat-restistant polypropylene involves low costs, the so-called fluorine plastics, polysulphides and polyimides are relatively expensive.

Baier, R.

1981-03-11

 
 
 
 
121

Effects of tungsten content on the creep-rupture properties of low-carbon cobalt-base heat-resistant alloys  

Science.gov (United States)

The effects of tungsten (W) content up to about 20 wt pct on the creep-rupture properties of low-carbon HAYNES 25-(L-605-) type cobalt-base alloys were investigated at 1089 and 1311 K. An increase in W content of about 5 wt pct resulted in tripling the rupture life without significant loss of creep ductility at 1311 K. The principal strengthening phases precipitated during creep at 1311 K were W solid solution and M6C carbide precipitates in the matrix and on the grain boundaries. The amounts of these precipitates, especially precipitates of W solid solution, increased with increasing W content. The Cr23C6 carbide was also detected in those ruptured specimens of alloys containing more than 17 wt pct W. The creep ductility decreased a little, and the rupture life did not increase with increasing W content at 1089 K. Two types of carbides (Cr23C6 and M6C), Co2W (Laves phase), and ? -Co were confirmed in the specimens ruptured at 1089 K. The amount of Co2W harmful to ductility, as well as the amounts of strengthening phases (carbides), increased with increasing W content.

Tanaka, Manabu; Iizuka, Hiroshi

1992-02-01

122

Anodic corrosion of Hastelloy-C in sulfuric acid solution  

International Nuclear Information System (INIS)

[en] The corrosion behavior of anodically polarized Hastelloy-C was investigated in an 1N sulfuric acid solution by using various methods as follows; e.g. potentiostatic and potentiokinetic polarization characteristic measurements, colorimetric analyses of the dissolved alloy elements and ESCA method. Both of the two kinds of polarization characteristic measurements gave results indicating that the alloy behaved in three different ways according to the potential from -0.2 to 1.0 Volt vs S.C.E. Below 0.2 V, although iron tended to selectively dissolve, the total amount of dissolution was very slight and the alloy was almost maintained in a passive state. At the potential between 0.2 and 0.8 V, local attack of the alloy and selective dissolution of molybdenum were observed. The electrolytic current reached its maximum value at 0.6 V, and a steep rise of the current was observed at about 0.9 V. Above the latter potential, the alloy was uniformly attacked and all elements dissolved in proportional manner to their alloy contents. Different ESCA spectra were also obtained according to the polarization potential. (auth.)

1978-01-01

123

Hot deformation of heat-resistant superalloys -- An overview  

Energy Technology Data Exchange (ETDEWEB)

The hot deformation behavior was investigated for four heat-resistant Ni-, Fe-, and Co-base superalloys: Haynes 188, 230, 556, and HR-160. Compression tests were conducted over a wide range of processing conditions. The flow behavior and deformed microstructures were characterized, while recrystallized grain size and percentage of recrystallization were measured for deformed specimens under selected conditions. From the experimental data, constitutive equations and microstructure maps were constructed. During the high temperature deformation, a number of mutually interacting metallurgical processes, such as dynamic recrystallization and precipitation, occurred. Their influence on hot formability and deformed microstructure have been represented by deformation microstructure maps that can serve as a guideline for hot deformation process design and subsequent heat treatment after hot forming. The workability and deformation behaviors of the heat-resistant alloys are also compared in The light of alloy development to ensure the fabricability of newly developed alloys.

Chaudhury, P.K.; Zhao, D.; Thirukkonda, M.; Guillard, S. [Concurrent Technologies Corp., Johnstown, PA (United States)

1995-12-31

124

Heat-resistant materials 2. Conference proceedings of the 2. international conference on heat-resistant materials  

Energy Technology Data Exchange (ETDEWEB)

The Second International Conference on Heat-Resistant Materials was held in Gatlinburg, Tennessee, September 11--14, 1995 and focused on materials performance in cross-cutting technologies where heat resistant materials play a large and sometimes life-and performance-limiting roles in process schemes. The scope of materials for heat-resistant applications included structural iron- and nickel-base alloys, intermetallics, and ceramics. The conference focused on materials development, performance of materials in simulated laboratory and actual service environments on mechanical and structural integrity of components, and state-of-the-art techniques for processing and evaluating materials performance. The three keynote talks described the history of heat-resistant materials, relationship between microstructure and mechanical behavior, and applications of these materials in process schemes. The technical sessions included alloy metallurgy and properties, environmental effects and properties, deformation behavior and properties, relation between corrosion and mechanical properties, coatings, intermetallics, ceramics, and materials for waste incineration. Seventy one papers have been processed separately for inclusion on the data base.

Natesan, K. [ed.] [Argonne National Lab., IL (United States); Ganesan, P. [ed.] [INCO Alloys International, Inc., Huntington, WV (United States); Lai, G.Y. [ed.] [Haynes International, Inc., Kokomo, IN (United States)

1995-12-31

125

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

126

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

Energy Technology Data Exchange (ETDEWEB)

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

Fullam, H.T.

1980-03-01

127

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

Science.gov (United States)

The permeation of hydrogen isotopes through the Hastelloy XR high-temperature alloy adopted for the heat transfer pipes of the intermediate heat exchanger in the HTTR, is one of the concerns in the hydrogen production system, which will be connected to the HTTR in the near future. The hydrogen permeation between the primary and secondary coolants through the Hastelloy XR was evaluated using the actual hydrogen concentrations observed during the initial 950 °C operation of the HTTR. The hydrogen permeability of the Hastelloy XR was estimated conservatively high as follows. The activation energy E0 and pre-exponential factor F0 of the permeability of hydrogen were E0 = 65.8 kJ/mol and F0 = 7.8 × 10-9 m3(STP)/(m s Pa0.5), respectively, in the temperature range from 707 to 900 K.

Sakaba, Nariaki; Ohashi, Hirofumi; Takeda, Tetsuaki

2006-07-01

128

Hydrogen permeation of Hastelloy XR for high temperature gas-cooled reactors  

International Nuclear Information System (INIS)

[en] Hydrogen permeation of Hastelloy XR, which was developed for high-temperature gas-cooled reactors, has been investigated with a simulated gas to the reactor environment, 80% H2+15% CO+15% CO+5% CO2. In this gas environment, Hastelloy XR formed chromium oxide and manganese-spinel oxide on the surface and showed a good quality to prevent hydrogen permeation. The prevention behavior can be interpreted in terms of a hydrogen diffusion model in a uniform oxide layer, and dependences of permeation rate on time and temperature are explained by variation of oxide thickness. The pressure dependence of the permeation rate for the oxidized alloy as well as bare metals obeyed Sieverts' law. The environmental effects on hydrogen permeation are also discussed on the basis of correlation between the characteristics of the surface layer and the permeation behaviors. (orig.)

1984-01-01

129

Fatigue and uniaxial deformation behavior of Hastelloy XR at elevated temperatures  

International Nuclear Information System (INIS)

[en] 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

130

Technology and application of heat resistant concretes  

Energy Technology Data Exchange (ETDEWEB)

Theoretical grounds for creating heat resistant concretes are reviewed, potential application of concretes at high temperatures is established as well as the principles for calculating and designing thermal assemblies of heat resistant concretes, preparation procedure, placing and operation of linings made of these concretes. It is shown that nowadays all necessary scientific and technological prerequisites are created for a wide application of thermal units and structures made of heat resistant concretes and reinforced concretes operating under conditions of elevated and very high temperatures. These prerequisites comprise the development of compositions of heat resistant concretes to be used in a wide temperature range (200-1700 deg C), procedure of industrial production, scientifically based principles of designing and calculating heat-resistant concrete- and reinforced concrete structures and appropriate standard documentation.

Nekrasov, K.D. (Nauchno-Issledovatel' skij Inst. Betona i Zhelezobetona Gosstroya SSSR)

1984-06-01

131

Larson-Miller Constant of Heat-Resistant Steel  

Science.gov (United States)

Long-term rupture data for 79 types of heat-resistant steels including carbon steel, low-alloy steel, high-alloy steel, austenitic stainless steel, and superalloy were analyzed, and a constant for the Larson-Miller (LM) parameter was obtained in the current study for each material. The calculated LM constant, C, is approximately 20 for heat-resistant steels and alloys except for high-alloy martensitic steels with high creep resistance, for which C ? 30 . The apparent activation energy was also calculated, and the LM constant was found to be proportional to the apparent activation energy with a high correlation coefficient, which suggests that the LM constant is a material constant possessing intrinsic physical meaning. The contribution of the entropy change to the LM constant is not small, especially for several martensitic steels with large values of C. Deformation of such martensitic steels should accompany a large entropy change of 10 times the gas constant at least, besides the entropy change due to self-diffusion.

Tamura, Manabu; Abe, Fujio; Shiba, Kiyoyuki; Sakasegawa, Hideo; Tanigawa, Hiroyasu

2013-06-01

132

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

133

Trends of improvement of heat resistance of engineering plastics. Enpura no tainetsuka no doko  

Energy Technology Data Exchange (ETDEWEB)

This paper presents the recent situation in improving heat resistance of engineering plastics. Plastics with heat resistance of 100[degree]C to 150[degree]C are called general purpose engineering plastics, and those of higher than 150[degree]C are called super engineering plastics. Studies are under way to improve heat resistance of such general purpose engineering plastics as polymer alloy, polyamide, and polyester to that of super engineering plastics. In the super engineering plastics, polyether sulphone plastics improved of heat resistance in polysulphone include those with heat deformation temperature (HDT) of 203[degree]C and 234[degree]C. Polyether etherketone plastics have superior heat resistance, chemical resistance, and sliding characteristics, and include those with Tm of 315[degree]C and 340[degree]C. Polyether ketone have those with Tm of 360[degree]C and 373[degree]C. Polyphenylene sulfide plastics have superior heat resistance, rigidity, dimensional stability, chemical resistance, and flame retardation. Liguid crystal polymers have high formability, dimensional accuracy, low burr property, heat resistance, and flame retardability, and products with HDT of 270[degree]C have been developed. 11 refs., 7 tabs.

Inoue, T. (Toray Industries, Inc., Tokyo (Japan). Plastics Research Laboratories)

1992-09-20

134

Heat resistant fungi isolated from soil.  

UK PubMed Central (United Kingdom)

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

Piecková E; Bernát D; Jesenská Z

1994-06-01

135

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

136

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

International Nuclear Information System (INIS)

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

1980-01-01

137

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

138

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

139

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

140

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

 
 
 
 
141

Viral heat resistance and infectious ribonucleic acid.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

High-titer suspensions of poliovirus 1 and coxsackievirus B-2 were shown to contain a heat-resistant fraction when heated for 65 min at temperature ranging from 56 to 70 degrees C. The addition of ribonuclease to the heated suspensions eliminated plaque production in the cell cultures, indicating th...

Larkin, E P; Fassolitis, A C

142

Low-cycle fatigue of Hastelloy X and Hastelloy XR in simulated VHTR helium coolant environment at elevated temperature  

International Nuclear Information System (INIS)

[en] Strain-controlled low-cycle fatigue tests were conducted on Hastelloy X and its modified version, Hastelloy XR, at 900 sup( o)C in the flowing simulated VHTR helium environment. The results of this study provide the following conclusions; 1) Hastelloy X and Hastelloy XR exhibited essentially the same low-cycle fatigue characteristics under the given test conditions, where marked difference was observed in the oxidation performance between those materials. The results obtained in the present work were in good accordance with the following equation proposed by Manson and Coffin ? epsilon sub(t) = ? epsilon sub(e) + ? epsilon sub(p) = 0.00228 Nsub(f)sup(-0.00732) + 0.447 Nsub(f)sup(-0.604) 2) The ratio of Nsup(f) in impure helium to Nsup(f) in 1--3 x 10-6 Pa vacuum were examined, and the results were equally about 0.7 for both materials. 3) Both transgranular fracture mode with ductile striations and intergranular fracture mode were recognized in the fracture surfaces, with the former mode being predominant. 4) The results obtained in the present work were situated on the line corresponding to the approximate average level of the available fatigue data in literature on Hastelloy X tested under similar test conditions. (author)

1984-01-01

143

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; M. Arici

2006-01-01

144

Heat resisting cellulase gene, recombinant engineering bacterium, heat resisting cellulase and use  

UK PubMed Central (United Kingdom)

The invention belongs to the bioengineering field, which particularly relates to a heat-resistant cellulase gene, a recombinant vector, a cellulase gene engineering strain, a heat-resistance cellulase derived from Fervidobacterium and the application thereof. The heat-resistant cellulase (FnCel5A and FnNHCel5A) carries out high-efficiency catalytic reaction under the high temperature condition (70-80 DEG C), the heat-resistant cellulase has very good stability and has the advantages of low storage and transport cost, accelerating kinetic reaction and low requirement standard for the cooling system of a reactor in production. Meanwhile, the FnCel5A and the FnNHCel5A are the heat-resistant cellulase with single endonuclease activity and can be widely applied to the field of cellulose processing. The heat-resistant recombinant cellulase can also be applied to the aspects of detergents, waster water treatment, animal feeds, and the like, or applied to the textile industry, the recycled paper production industry, the industry of extracting active components from plants, the juice processing industry, etc.

YAN FENG; XIAONAN WANG; YUGUO WANG; ZUOMING ZHANG; BAISONG ZHENG

145

Application of newly developed heat resistant materials for USC boilers  

International Nuclear Information System (INIS)

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

2004-01-01

146

Application of newly developed heat resistant materials for USC boilers  

Energy Technology Data Exchange (ETDEWEB)

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

Sato, T.; Tamura, K.; Fukuda, Y. [Kure Research Lab., Babcock-Hitachi K.K., Hiroshima (Japan); Matsuda, J. [Kure Div., Babcock-Hitachi K.K., Hiroshima (Japan)

2004-07-01

147

Heavy radiation effects on heat resistant steels  

Energy Technology Data Exchange (ETDEWEB)

R and D of heat resistant steels as structural materials for fusion reactor is one of the most important parts of fusion technology. This paper provides some of the recent results of heavy radiation effects on austenitic stainless steels, ferritic steels and reduced activation steels from FFTF cycle 10/MOTA-1F specimens with the emphasis on F82H reduced activation martensitic steel. Microstructural evolution and mechanical property changes are reviewed. (author).

Kohno, Yutaka (Tokyo Univ. (Japan). Faculty of Engineering)

1992-06-01

148

CORN CULTIVAR IDENTIFICATION THROUGH HEAT RESISTANT PROTEINS  

Directory of Open Access Journals (Sweden)

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

SOLANGE CARVALHO BARRIOS ROVERI JOSÉ; ÉDILA VILELA DE RESENDE VON PINHO; KALINKA CARLA DE CARVALHO SALGADO; RENZO GARCIA VON PINHO

2004-01-01

149

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.

2012-01-01

150

Metallurgical and environmental factors influencing creep behaviour of hastelloy-X  

International Nuclear Information System (INIS)

[en] 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

151

Flexible heat resistant neutron shielding resin  

International Nuclear Information System (INIS)

A flexible heat resistant neutron shielding material has been developed, which consists of polymer resin with 1 wt% boron. The neutron shielding performance of the developed resin, examined by the 252Cf neutron source, is almost the same as that of the polyethylene. The outgas of H2, H2O, CO and CO2 from the resin have been measured at ?250 deg. C environment. The resin will be applied around the port of the vacuum vessel as an additional shielding material and reduce the neutron streaming from a superconducting tokamak device such as JT-60SA.

2011-10-01

152

Heat-resistant coating for gas turbines. 1; Gas turbine yo tainetsu coating. 1  

Energy Technology Data Exchange (ETDEWEB)

Requisites about high-temperature resistance imposed on gas turbine high-temperature parts are quite stringent, and voices are high seeking for high-performance heat-resistant materials that can satisfy such requisites. It is supposed, however, that a pretty long time has to elapse before ceramic-based materials or intermetallic compounds may be introduced into real machines. In this context, the only measure that can be resorted to is to go on improving the available coating-reinforced heat-resistant materials, based on the super-heat-resistant alloys that are currently the main materials for high-temperature parts, so that they will stay serviceable under increasingly severe critical operating conditions. In this sense, the coating technology should be regarded as an essential element that directly governs the service life of parts. Described in this report are the progress of research and development, superalloys and their heat-resistant coatings, examples of failure analyses of coatings experienced during actual machine operation or research, and progress in the future. 24 refs., 8 figs., 2 tabs.

Yoshiba, M. [Tokyo Metropolitan Univ., Tokyo (Japan)

1997-06-10

153

Heat resistant suit with active cooling system  

UK PubMed Central (United Kingdom)

A heat resistant suit includes an inner garment designed to circulate cooling air against the wearer's body. The inner garment is connected to the cool air output of a vortex carried in a pocket in an outer, heat reflective coverall. A safety bottle is carried in another pocket of the coverall, with the safety bottle connected to a pressure valve which is also connected to an external source of breathing air. The vortex unit is connected to an external air compressor which can also be used to supply filtered, pressure regulated breathing air which is cooled by a second vortex unit. A safety harness is sewn into the coverall, with the safety harness connected to a pull ring attached to the rear of the coverall. The outer coverall is preferably constructed of KEVLAR cloth to which an external aluminum reflective coating is applied.

RANKIN R DEWON; RANKIN II ROGER D; RANKIN CURT N

154

Composite materials for heat-resistant structures  

Energy Technology Data Exchange (ETDEWEB)

Methods by which the mechanical properties of ceramic composite materials (CCM) can be improved are discussed. The proposed approach consists of introducing, at high temperature, a plastic phase into the brittle particulate matrix. Two CCM samples: (1) CCM-1, composed of SiC, Si/sub 3/N/sub 4/, and SiO/sub 2/ powders, and (2) CCM-2, composed of SiC and Si/sub 3/N/sub 4/ powders and liquid glass, were prepared by a method of cold pressing followed by baking. Results are given on the heat resistance and strength of the materials at temperatures of 120-1700 K. Reference is made to the use of such materials in the development of ceramic gas-turbine engines.

Trofimov, V.V.; Beloturov, V.I.; Gracheva, L.A.

1985-01-01

155

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

Directory of Open Access Journals (Sweden)

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

A. Patejuk; M. Gabrylewski; P. Baranowski

2009-01-01

156

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

157

Electron Microscopic Analysis of Heterogeneous Precipitates in Hastelloy C-276  

Science.gov (United States)

Three distinct second phases were observed to form heterogeneously at grain and deformation twin boundaries when Hastelloy C-276 was aged in the temperature range of 923 to 1173 K. The most abundant was the faulted, molybdenum rich ? phase. The next most abundant phase was molybdenum rich M6C carbides, and the third phase, which was observed very infrequently, was tentatively identified as the P phase. The compositions of these phases were remarkably similar, and the need to employ several electron microscopy techniques is emphasized. The origin of the ? phase is discussed in the light of its chemistry.

Raghavan, M.; Berkowitz, B. J.; Scanlon, J. C.

1982-06-01

158

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

159

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

160

Adhesive strength of heat-resistant glass ceramic coatings with nichrome melts  

Energy Technology Data Exchange (ETDEWEB)

The basic factor on which the operating properties of heat-resistant glass ceramic coatings are dependent is the strength of adhesion of the coatings to the metal, primarily determined by the structure and phase composition of the metal-coating transition layer. The effect of iron oxide on the structure and phase composition of the nichrome alloy-glass ceramic coating transition layer and adhesive strength of the coatings as a function of structure and phase composition of the transition layer are discussed.

Zubekhin, A.P.; Zhabrev, V.A.; Kondyurin, A.M.

1994-09-01

 
 
 
 
161

A study on heat resistance of high temperature resistant coating  

International Nuclear Information System (INIS)

A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

2005-01-01

162

A study on heat resistance of high temperature resistant coating  

Energy Technology Data Exchange (ETDEWEB)

A high temperature resistant coating has been developed, which is mainly for heavy oil production pipes deserved the serious corrosion. The coating has excellent physical and mechanical performance and corrosion resistance at room and high temperature. In order to simulate the underground working condition of heavy oil pipes,the heat resistance of the high temperature resistant coating has been studied. The development and a study on the heat resistance of the DHT high temperature resistance coating have been introduced in this paper

Zhang, Liping; Wang, Xueying; Zhang, Qibin; Qin, Yanlong; Lin, Zhu [Research Institute of Engineering Technology of CNPC, Tianjin (China)

2005-04-15

163

Yttrium addition to heat-resistant cast stainless steel  

International Nuclear Information System (INIS)

[en] Yttrium addition to HP-type (where H stands for heat-resistant and P is related to the Ni content) heat-resistant cast stainless steel resulted in increased fragmentation of the primary chromium carbide network and improved high temperature mechanical properties. The improvement was caused by yttrium carbide particles acting as nucleation sites for other carbides, as indicated by transmission electron microscopy and energy dispersive X-ray spectroscopy analysis. Thermodynamic considerations support these conclusions

2006-01-01

164

Development of super heat-resistant turbocharger  

Energy Technology Data Exchange (ETDEWEB)

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

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

1987-09-01

165

An Experimental Study on Heat Resistance by Split Dose Hyperthermia  

International Nuclear Information System (INIS)

The study was undertaken to evaluate the heat resistance by split dose hyperthermia in various time interval and temperature. For the experiments, 96 mice were divided into 2 groups: the first, 36 mice were used to evaluate the skin reaction of mouse tail to single dose hyperathermia, the second, 60 mice were used to evaluate heat resistance by split dose hyperthermia in various time intervals. The results obtained are summarized as follows: 1. The ND'5'0 was 101 minutes at 43 .deg. C and 24 minutes at 45 .deg. C. 2. For a 1 .deg. C increase in temperature, a half in time was required to same degree of skin reaction. 3. Heat resistance was significantly developed in split dose hyperthermia at 43 .deg. C and 45 .deg. C 4. Development, maximum and decay of heat resistance were constant regardless of change in temperature. In summary, heat resistance in split dose hyperthermia is important in study and clinical application of heat therapy in malignant disease.

1983-01-01

166

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; Yu Mukai; Ilhyong Ryu

2011-01-01

167

Heat-resistant cast steel for heat-treatment plant  

Energy Technology Data Exchange (ETDEWEB)

Cast steel has proved successful as a heat-resistant engineering material for components of heat-treating furnaces. The stress pattern acting on such components varies widely according to operating conditions. The author first describes the demands which such engineering materials, have to meet and then cites a number of examples where heat-resistant cast steel can be used to advantage. The author finally points to the possibility of improving operational economy of such furnaces by reducing the volume of structural members.

Steinkusch, W.

1987-08-01

168

Study on the heat-resistant EB curing composites  

Energy Technology Data Exchange (ETDEWEB)

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)

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

2000-03-01

169

Plasma method for separation of heat-resistant metals  

Energy Technology Data Exchange (ETDEWEB)

The regime of burning of a high-pressure arc is considered when its positive column contains an admixture of a heat-resistant metal, which is located in the form of a gaseous compound near walls of the discharge tube and metallic clusters in a hot region of this discharge. Criteria of this discharge regime are given. A cluster instability leads to the growth of metallic clusters in an intermediate region of the discharge. This instability is a basis for separation of a heat-resistant metal in the plasma from its chemical compounds. (c) 2000 American Institute of Physics.

Smirnov, B. M. [Institute for Nuclear Theory, University of Washington, Box 351550, Seattle, Washington 98195 (United States)

2000-04-01

170

Highly heat-resistant thermoplastics. Processing and application in electronics  

Energy Technology Data Exchange (ETDEWEB)

Electical grade plastics are commonly subjected to hard stress, first under the straining conditions of modern mass production and afterwards in its service function, and this all the more accentuated as there is a trend for miniaturization. One of the main requirements electrical grade plastics have to meet, is heat resistance. Highly heat-resistant and injectionable grades are available for such purposes. Particularly good results are obtained with polyphenylene sulfide (PPS). Information is given on its characteristics, permissible exposure to heat, and the conditions to comply with at processing and in service time.

Bednarz, J.

1981-04-01

171

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)

2000-01-01

172

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

173

R and D of the heat-resistant LH antenna  

Energy Technology Data Exchange (ETDEWEB)

Two different types of Lower Hybrid Current Drive (LHCD) antenna having high-heat resistant property are developed according to a pulse length and/or working frequency. In the first type of LH antenna, heat resistive material is installed at the antenna mouth only and should be attachable using bolts. This heat-resistant mouth is exchanged for a new one when it is damaged. The heat-resistant mouth is made of Carbon Fiber Composite (CFC)-block bonded with stainless steel-base machined to fit the waveguides. This mouth has no Cu-plating for reducing rf-losses, because the antenna is designed to operate during 10-100 s injection of 2 GHz in JT-60SC. The second antenna consists of a compact multi-junction (MJ) part and a power divider designed for the next generation tokamak machine like ITER. This MJ must be made of low-Z material as a plasma facing component allowing no degradation in confinement. The test module for the MJ is made of rods and plates of CFC with Cu-plating {approx}30 cm in length. The test module shows transmitted power availability up to 45 MW/m{sup 2} over 1000 s with cooling at 3.7 GHz. For improvement of transmitted power availability, R and D of strong Cu-plating on CFC surface has been progressed using an electrochemical method.

Seki, M. E-mail: seki@naka.jaeri.go.jp; Maebara, S.; Fujii, T

2001-10-01

174

Thermal response of heat-resistant layer with pyrolysis  

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 ...

Huang Haiming; Xiaoliang Xu; Huang Guo; Zhang Zimao

175

Humidity affects genetic architecture of heat resistance in Drosophila melanogaster.  

UK PubMed Central (United Kingdom)

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 OA; Kristensen TN; Kellermann V; Loeschcke V

2012-06-01

176

Enumeration of Byssochlamys and Other Heat-Resistant Molds 1  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Methods for the detection of low numbers of heat-resistant molds on fruits were studied by using cultures of Byssochlamys and a number of unidentified mold isolates. Ascospore dormancy had a marked effect on viable recoveries, and the medium in which ascospores were heated influenced activation rate...

Splittstoesser, D. F.; Kuss, F. R.; Harrison, Wanda

177

Long-term behaviour of heat-resistant steels and high-temperature materials. Langzeitverhalten warmfester Staehle und Hochtemperaturwerkstoffe  

Energy Technology Data Exchange (ETDEWEB)

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

1987-01-01

178

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)

2011-01-01

179

High temperature low-cycle fatigue strength of Hastelloy X  

International Nuclear Information System (INIS)

[en] Isothermal low-cycle fatigue tests including both load controlled and strain controlled tests were conducted on Hastelloy X, one of the materials for VHTR (Very High Temperature Gas Cooled Reactor). The effects of temperature, atmosphere, strain rate and hold time were studied. Special attention was given to the creep-fatigue criteria. The results are summarized as follows. (1) In the simulated VHTR He gas, the fatigue life increases as compared with that in air for the test without any strain hold time, but remains almost unchanged for the test with a long strain hold time. (2) In the temperature range from 800 to 10000C, the Coffin-Manson relationship holds between plastic strain range and fatigue life, but it does not agree well with the result estimated from the tensile test. (3) The relationships between plastic strain range and fatigue life obtained from the strain controlled test under different strain rates and strain hold times are almost equal. The fatigue life under the strain controlled test can be estimated using these relationships. (4) The result of the load controlled test agrees well with that obtained by applying the linear damage rule on the assumption that the total damage consists of the two kinds of damages caused by cyclic plastic strain and by accumulation of creep strain on one side. The both damages can be calculated by applying the life fraction rule to the relationship between plastic strain range and fatigue life and to that between stress and creep rupture ductility, respectively. (auth.)

1977-01-01

180

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

 
 
 
 
181

Determination of Heat Resistance of Exponential Phase Enterococcal Cells  

Directory of Open Access Journals (Sweden)

Full Text Available The heat resistance of exponential phase cells of environmental barley isolates Enterococcus faecium BAR 1 and a hospital isolate Enterococcus faecalis MI 2 grown at 37 or 45 was determined at 55, 60 and 62.5 ° C for 30 min. From the survival curves, the decimal reduction times (D-values) were determined. Cells grown at 45° C showed higher D-values. It was determined that the exponential phase cells grown at 45 were more resistant to heat than the heat resistance of cells grown at 37° C. The cells of both isolates were found resistant to heat treatment at 55, 60 and 62.5 as compared with the control in which cells were grown at 37° C and treated at 62.5° C.

Mushtaq Ahmad; David G. Smith; S. Mahboob

2003-01-01

182

WATER- AND HEAT-RESISTANT SCRATCH-AND-SNIFF COATING  

UK PubMed Central (United Kingdom)

A scratch-and-sniff coating is provided comprised of a first coating on a substrate having a water- and heat-resistant second coating thereon, the first coating being comprised of a non-encapsulated flavor/fragrance component and a polysaccharide component, and the second coating comprised of a shellac component. The scratch-and-sniff coating is made by forming a first coating comprised of a non-encapsulated flavor/fragrance component and a polysaccharide component and drying the first coating, and forming a water- and heat-resistant shellac-containing second coating on the first coating, and drying the second coating. An encapsulated flavor/fragrance component may optionally be present in the first coating. The scratch-and-sniff coating can be applied to a package for a consumer article.

DUAN BIAO

183

Heat resistance of thermoduric enterococci isolated from milk.  

UK PubMed Central (United Kingdom)

Enterococci are reported to survive pasteurisation but the extent of their survival is unclear. Sixty-one thermoduric enterococci isolates were selected from laboratory pasteurised milk obtained from silos in six dairy factories. The isolates were screened to determine log(10) reductions incurred after pasteurisation (63°C/30 min) and ranked from highest to lowest log(10) reduction. Two isolates each of Enterococcus faecalis, Enterococcus faecium, Enterococcus durans and Enterococcus hirae, exhibiting the median and the greatest heat resistance, as well as E. faecalis ATCC 19433, were selected for further heat resistance determinations using an immersed coil apparatus. D values were calculated from survival curves plotted from viable counts obtained after heating isolates in Brain Heart Infusion Broth at 63, 69, 72, 75 and 78°C followed by rapid cooling. At 72°C, the temperature employed for High Temperature Short Time (HTST) pasteurisation (72°C/15s), the D values extended from 0.3 min to 5.1 min, depending on the isolate and species. These data were used to calculate z values, which ranged from 5.0 to 9.8°C. The most heat sensitive isolates were E. faecalis (z values 5.0, 5.7 and 7.5°C), while the most heat resistant isolates were E. durans (z values 8.7 and 8.8°C), E. faecium (z value 9.0°C) and E. hirae (z values 8.5 and 9.8°C). The data show that heat resistance in enterococci is highly variable.

McAuley CM; Gobius KS; Britz ML; Craven HM

2012-03-01

184

Heat resistant protective clothing. Vetements de protection thermique  

Energy Technology Data Exchange (ETDEWEB)

This report begins by reviewing the recent published literature on protective clothing made from high performance fabrics, with particular reference to comparative test methods. A method used by Centexbel for testing the performance of clothing against convective heat, based upon ASTM-D 11-77-4, is described in detail. Interpretation of test results is discussed in relation to heat resistance factors calculated by Stoll and Chianta.

Smissaert, L.

1983-01-01

185

Heat Resistance of Salmonella: the Uniqueness of Salmonella senftenberg 775W  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Of approximately 300 cultures of Salmonella, representing 75 different serotypes, none was found to be as heat-resistant as S. senftenberg 775W. However, S. blockley 2004 was 5 times more heat-resistant and S. senftenberg 775W was 30 times more heat-resistant than S. typhimurium Tm-1, the reference ...

Ng, Henry; Bayne, Henry G.; Garibaldi, John A.

186

Heat resistant bovine colostrum immunoglobulin and preparation method  

UK PubMed Central (United Kingdom)

The invention discloses a heat resisting bovine colostrum immunoglobulin and a preparation method thereof, which is characterized in that two times of centrifugations are carried out to bovine colostrum to respectively remove fat and casein ultrafiltration is carried out, then thermal denatured protective agents formed by fructo oligosaccharides, sorbitol, oligomeric maltose and glycine are added into the bovine colostrum, and at last heat resisting bovine colostrum immunoglobulin is prepared by low-temperature spray drying. Compared with common bovine colostrum immunoglobulin, the heat-resisting temperature of the immunoglobulin of the invention is increased by 12 to 15 DEG.C next, the contents of the immunoglobulin can reach to above 40 percent and is 20 to 30 percent higher than that of the immunoglobulin in common bovine colostrum besides, the preparation method of the invention is low in energy consumption and cost, and by utilizing the technologies of ultrafiltration and concentration and low-temperature spraying, energy consumption is reduced by 50 percent compared with a freeze drying technology.

XUECHU YU; YONGKANG LUO

187

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

188

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

189

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

International Nuclear Information System (INIS)

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

2008-03-25

190

Heat-resistant coatings for the high-pressure turbine blades of promising GTEs  

Science.gov (United States)

Heat-resistant coatings are considered for the external surface of high-pressure turbine (HPT) single-crystal blades for promising gas turbine engines (GTEs) made from carbon-free nickel superalloys with rhenium or rhenium plus ruthenium. Nickel superalloys covered with heat-resistant coatings consisting of heat-resistant connecting layers and an external ZrO2-(7-8 wt %)Y2O3 ceramic layer are subjected to heat resistance and high-temperature tests. The test results are used to choose the heat-resistant layer that ensures the highest properties of a composition heat-resistant coating. The use of sequential chemical and physical deposition methods for coating layers is shown to be required to protect HPT blades in promising GTEs. Medium-frequency magnetron plasmachemical deposition of ceramic layers in heat-resistant coatings with a low thermal conductivity is found to be promising.

Kablov, E. N.; Muboyadzhyan, S. A.

2012-01-01

191

Role of Nb in modifying the microstructure of heat-resistant cast HP steel  

Energy Technology Data Exchange (ETDEWEB)

Heat-resistant cast stainless steels have widespread uses in the petrochemical industry in pyrolysis and reformer furnaces; 25%Cr-20% Ni or 25% CR-33% NI high-carbon steels, designated HK and HP types, respectively, have traditionally been used, but requirements for higher productivity have raised the demand for improved performance. In the more recently developed steels, the Cr carbides normally present are replaced by carbides of Nb or Ti, or both, and the resulting alloys are termed modified HK or modified HP steels. The additions of Nb or Ti provide improved structural stability at high temperature in that their carbides are more stable than the normal secondary carbide precipitates of Cr, thus contributing to restraint of dislocation movement. Perhaps more important still is the eutectic modification caused by Nb additions that could restrict grain boundary sliding. This article reports on an investigation into the role of Nb in modifying the microstructure of HP steel in the as-cast and artificially aged conditions, for a series of alloys utilizing different levels of Nb.

Barbela, G.D.; de Almeida, L.H.; Silveira, T.L.; May, I.L. (COPPE/URFI, P.O. Box 68505, 21945 Rio de Janiero (BR))

1991-04-01

192

Study of Rigid Cross-Linked PVC Foams with Heat Resistance  

Directory of Open Access Journals (Sweden)

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

Aihua Shi; Guangcheng Zhang; Chenhui Zhao

2012-01-01

193

Study of rigid cross-linked PVC foams with heat resistance.  

UK PubMed Central (United Kingdom)

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

Shi A; Zhang G; Zhao C

2012-01-01

194

Self-healing epoxy composite with heat-resistant healant.  

UK PubMed Central (United Kingdom)

To provide self-healing epoxy composite with adequate heat resistance for high-performance application, we developed a novel microencapsulated epoxy/mercaptan healing agent. The key measure lies in usage of diglycidyl ether of bisphenol A (EPON 828) as the polymerizable component and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) as the catalyst. Because of the higher thermal stability of EPON 828 and lower volatility of DMP-30, the healing agent and the self-healing composite not only survive high-temperature curing and thermal exposure, but also offer satisfactory capability of autonomous properties restoration, as characterized by both fracture mechanics and fatigue tests. Especially when the operation temperature is not higher than 200 °C, the performance of the healing system is nearly independent of thermal history.

Yuan YC; Ye XJ; Rong MZ; Zhang MQ; Yang GC; Zhao JQ

2011-11-01

195

Self-healing epoxy composite with heat-resistant healant.  

Science.gov (United States)

To provide self-healing epoxy composite with adequate heat resistance for high-performance application, we developed a novel microencapsulated epoxy/mercaptan healing agent. The key measure lies in usage of diglycidyl ether of bisphenol A (EPON 828) as the polymerizable component and 2,4,6-tris(dimethylaminomethyl)phenol (DMP-30) as the catalyst. Because of the higher thermal stability of EPON 828 and lower volatility of DMP-30, the healing agent and the self-healing composite not only survive high-temperature curing and thermal exposure, but also offer satisfactory capability of autonomous properties restoration, as characterized by both fracture mechanics and fatigue tests. Especially when the operation temperature is not higher than 200 °C, the performance of the healing system is nearly independent of thermal history. PMID:21991982

Yuan, Yan Chao; Ye, Xiao Ji; Rong, Min Zhi; Zhang, Ming Qiu; Yang, Gui Cheng; Zhao, Jian Qing

2011-10-24

196

Absorption of molten fluoride salts in glassy carbon, pyrographite and Hastelloy B  

Energy Technology Data Exchange (ETDEWEB)

Materials performance is one of the issues of the accelerator driven transmutation technology (ADTT). Identification of the materials, which would satisfy the strength and integrity requirements for the target-blanket assembly (e.g. corrosion and radiation resistance), is a significant challenge. We report on the study of the interaction (i.e. penetration and capture) of molten fluoride salts with glassy carbon, pyrolitic graphite, and Hastelloy B, which are considered as candidates for structural materials of the ADTT systems. Massive penetration into and capture of molten fluorides within a several micrometer thick surface layer was observed for all inspected specimens. The incorporation rate of the molten fluorides depends on the exposure time and temperature of the molten fluoride bath. The corrosion resistance of the specimens was verified in stationary conditions. Whereas excellent resistance has been found for pyrolitic graphite, evident corrosion was observed for glassy carbon and particularly for Hastelloy B.

Vacik, J. E-mail: vacik@taka.jaeri.go.jp; Naramoto, H.; Cervena, J.; Hnatowicz, V.; Peka, I.; Fink, D

2001-03-01

197

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

International Nuclear Information System (INIS)

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

1987-01-01

198

Development of new 11%Cr heat resistant ferritic steels with enhanced creep resistance for steam power plants with operating steam temperatures up to 650 deg. C  

International Nuclear Information System (INIS)

The goal of developing new heat resistant 11%Cr ferritic-martensitic steels with sufficient creep and oxidation resistance up to 650 deg. C was pursued within a joint project following an alloying concept based on physical metallurgy principles. The highest creep strength combined with good oxidation resistance was achieved for a Ta-alloyed test melt (11 wt.% Cr, W, Co, Mo, V, 0.09 wt.% Ta, relatively high contents of C and B). The microstructural evolution during creep was investigated by transmission electron microscopy for the Ta-alloyed melt in comparison to a sister melt where Ta was exchanged for 0.04%Nb. It is proposed that fine particles of types MX and M23C6 (M: metallic element, X: interstitial elements) are the cause of the outstanding creep resistance of the Ta-alloyed melt.

2009-06-15

199

Long-term hardness of alloys in the V-TiN, V-ZrN and V-HfN systems  

Energy Technology Data Exchange (ETDEWEB)

The structure and heat resistance were studied for cast alloys of quasi-binary V-TiN, V-ZrN and V-HfN systems. The method of long-term hardness was used to plot composition-heat resistance diagrams. The V-TiN system alloys with 3-6 vol. % of the nitride phase of the (V, Ti)N composition are most promising for development of heat-resistant compositions. An increased heat resistance of these alloys is explatined by a high cubic content of the nitride phase coherent presipitates and by appearance of strong tetragonal distortions in solid titanium solution in vanadium with nitrogen present.

Ban' kovskij, O.I.; Barabash, O.M.; Moiseev, V.F. (AN Ukrainskoj SSR, Kiev. Inst. Problem Materialovedeniya)

1982-04-01

200

Heat-resistant variants of Chinese hamster fibroblasts altered in expression of heat shock protein.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heat-resistant variants of the Chinese hamster HA-1 line have been isolated after repeated heat treatments. The heat-resistant phenotype has been stable for over 70 passages. One of the members of the 70-kDa heat shock protein family was found to be synthesized at greater levels in the heat-resistan...

Laszlo, A; Li, G C

 
 
 
 
201

Study of Rigid Cross-Linked PVC Foams with Heat Resistance  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Three heat resistant cross-linked PVC foam plastics were prepared and their performances were compared with universal cross-linked PVC structural foam. The results show that these three heat resistant foams have higher glass transition temperatures (close to 100 °C) than universal structural fo...

Aihua Shi; Guangcheng Zhang; Chenhui Zhao

202

Control of Byssochlamys and Related Heat-resistant Fungi in Grape Products  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heat-resistant strains of Byssochlamys fulva, B. nivea, and other heat-resistant fungi were isolated from vineyard soil, grapes, grape-processing lines, and waste pomace. They are known to remain in grape juice occasionally and to grow in grape juice products. Ascospores of these fungi have a D valu...

King, A. Douglas; Michener, H. David; Ito, Keith A.

203

Experimental industrial use of weighted heat resistant inverted-emulsion solution at the Salynskiy field  

Energy Technology Data Exchange (ETDEWEB)

The formula and technology for preparing a heat resistant inverted-emulsion solution with density 1550 kg/m/sup 3/ are examined. The experience indicated the effectiveness of using the weighted heat resistant inverted-emulsion solution in removing the core sample in the interval of occurrence of the Bazhenovskiy series in the Salynskiy field.

Lipkes, M.I.; Kas' yanov, N.M.; Ovchinskiy, K.Sh.

1982-01-01

204

Carburization behaviour of high temperature alloys in carburizing environment  

International Nuclear Information System (INIS)

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

1986-01-01

205

Method for homogenizing alloys susceptible to the formation of carbide stringers and alloys prepared thereby  

Energy Technology Data Exchange (ETDEWEB)

A novel fabrication procedure prevents or eliminates the reprecipitation of segregated metal carbides such as stringers in Ti-modified Hastelloy N and stainless steels to provide a novel alloy having carbides uniformly dispersed throughout the matrix. The fabrication procedure is applicable to other alloys prone to the formation of carbide stringers. The process comprises first annealing the alloy at a temperature above the single phase temperature for sufficient time to completely dissolve carbides and then annealing the single phase alloy for an additional time to prevent the formation of carbide stringers upon subsequent aging or thermomechanical treatment.

Braski, David N. (Oak Ridge, TN); Leitnaker, James M. (Kingston, TN)

1980-01-01

206

A life evaluation under creep-fatigue-environment interaction of Ni-base wrought alloys  

International Nuclear Information System (INIS)

[en] In order to determine a failure criteria under cyclic loading and affective environment for HTGR systems, a series of strain controlled low-cycle fatigue tests were carried out at HTGR maximum gas temperatures in air, in vacuum and in HTGR helium environments on two nickel-base wrought alloys, namely Inconel 617 and Hastelloy XR. This paper first describes the creep-fatigue-environment properties of these alloys followed by a proposal of an evaluation method of creep-fatigue-environment interaction based on the experimental data to define the more reasonable design criteria, which is a modification of the linear damage summation rule. Second, the creep-fatigue properties of Hastelloy XR at 900 deg C and the result evaluated by this proposed method are shown. This criterion is successfully applied to the life prediction at 900 deg C. In addition, the creep-fatigue properties of Hastelloy XR-II are discussed. (author)

1986-01-01

207

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.

Loredana Judele; I. Hîrhui; Livia Groll

2008-01-01

208

Experimental data on the thermal constants of heat resistant materials  

Energy Technology Data Exchange (ETDEWEB)

Determination of thermal constants of heat resistant materials was experimentally studied. Thermal conductivity (C) was measured by the hot-wire method (HWM). A nichrom heating wire is inserted closely between two specimens and the temperature of the specimens is kept constant. Then, the power is supplied at a constant rate to the wire to determine value of C from the temperature rise of the wire. To determine the heat transfer (H), a foil heater (the foil heater method, PHM) and a specimen are placed in close contact to each other and the power is applied to the heater at a constant rate in an electric furnace kept at a constant temperature. The heat transfer (H) was determined by the temperature rise of heater. The specific heat (heat capacity) and thermal diffusivity were determined from values of C and H. Values of C are in agreement with the direct plate method within +7 to 8% for HWM and -1 to +2% for FHM. Specimens used include: sprayed rock wool, asbestos Ca silicate board, asbestos rock-wool board, ordinary concrete and ALC. Highly reliable data was obtained from shrinking materials if the contact was sufficiently close. Values of C and the thermal diffusivity of many specimens increased by the temperature rise (decreased with concrete) and the heat capacity remained unchanged or decreased slowly. (19 figs, 1 tab, 7 refs)

Machida, Kiyoshi; Ouchi, Tomio; Kohira, Akio

1988-04-01

209

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)

2001-01-01

210

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

211

Testing heat resistant conveyor belts for transporting hot coke  

Energy Technology Data Exchange (ETDEWEB)

On-site testing of various types of conveyor belts for transporting hot coke in the wet quenching shops was conducted at the Kommunarskii coking plant. It was demonstrated that the service life of the six belt types tested was proportional to the thickness of the band and that the heat resistance of the cover material was not a determining factor. It was concluded that burnthrough could be prevented by increasing the standard cover thickness to 8-10 mm (instead of 3-6 mm) or by using a type-2 band having a cover thickness of 6-8 mm, a strength of 15 MPa, and based on a mixture of isoprene-3 and butadiene rubbers. Future belts should have coverings with the maximum possible strength (up to 20 MPa) and be thermal resistant and non-flammable, e.g. coverings based on ethylene propylene and butyl rubbers, a mixture of isoprene-3 with butadiene, or butadienestyrol rubbers, carcasses and coverings with asbestos, fiberglass or metallic mesh as well as antipyrenes which absorb heat and suppress stretching.

Anan' ev, N.V.; Golovin, P.D.; Svetlichnyi, I.F.

1985-01-01

212

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

213

Physical Simulation of Friction Stir Welding and Processing of Nickel-Base Alloys Using Hot Torsion  

Science.gov (United States)

The Gleeble hot torsion test was utilized in an attempt to simulate the friction stir-processed microstructure of three Ni-base alloys: Hastelloy X, Alloy 625, and Alloy 718. The simulation temperatures were based on actual thermal cycles measured by embedded thermocouples during friction stir processing of these alloys. Peak process temperatures were determined to be approximately 1423 K (1150 °C) for Hastelloy X and Alloy 625 K and 1373 K (352 °C and 1100 °C) for Alloy 718. The peak temperature and cooling rates were programed into the Gleeble™ 3800 thermo-mechanical simulator to reproduce the stir zone and thermo-mechanically affected zone (TMAZ) microstructures. The TMAZ was successfully simulated using this technique, but the stir zone microstructure could not be accurately reproduced, with hot torsion samples exhibiting larger grain size than actual friction stir processing trials. Shear stress and strain rates as a function of temperature were determined for each material using hot torsion simulation.

Rule, James R.; Lippold, John C.

2013-08-01

214

Bacillus sporothermodurans and other highly heat-resistant spore formers in milk.  

Science.gov (United States)

A recent example of a micro-organism causing undesired growth in consumer milk is Bacillus sporothermodurans producing highly heat-resistant spores (HRS) which may survive ultra-high temperature (UHT) treatment or industrial sterilization. Molecular typing showed a heterogeneous group of farm isolates (non-HRS strains), but a clonal group of UHT isolates from diverse European countries and other continents (HRS-clone) suggesting a common source. During a survey of Belgian dairy farms for the presence of potentially highly heat-resistant spore formers, high numbers of these spores were detected in filter cloth, green crop and fodder samples. The strain collection showed a high taxonomic diversity with 18 potentially new species and with Bacillus licheniformis and Geobacillus pallidus as predominating species overall. Seventeen B. sporothermodurans isolates were identified, mainly originating from feed concentrate. Heat resistance studies showed the UHT resistance of B. sporothermodurans spores present in industrially contaminated UHT milk, but a lower heat resistance of laboratory-grown strains (HRS and non-HRS). Hydrogen peroxide, used as sanitizer in the dairy industry, was found to induce higher heat resistance of laboratory-grown B. sporothermodurans strains to a certain level. This indicates that sublethal stress conditions may affect the heat resistance. By transmission electron microscopy, structural differences at the spore level were found between HRS and non-HRS strains. The data indicate that the attainment of extreme heat resistance is rather multifactorial. PMID:16907805

Scheldeman, P; Herman, L; Foster, S; Heyndrickx, M

2006-09-01

215

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

UK PubMed Central (United Kingdom)

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

Palop A; Raso J; Pagán R; Condón S; Sala FJ

1996-02-01

216

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

Science.gov (United States)

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

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

1996-02-01

217

Use of heat-resistant concretes for construction of coke batteries: an urgent problem  

Energy Technology Data Exchange (ETDEWEB)

Domestic and foreign experience in the construction of high-temperature equipment has demonstrated the advantages of monolithic and large-unit precast structures over structures of piecework refractory material. Heat-resistant concretes are a quite suitable material for monolithic and large-unit structures of the coking industry, especially for modern coke batteries and new plants for continuous production of coke. The prospects for monolithic and large-unit structures of heat-resistant concrete show the necessity of development of scientific investigations and industrial tests for the most rapid and efficient adoption of heat-resistant concrete in the coking industry.

Sibilev, A.I.; Sagalevich, Yu.D.

1980-01-01

218

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

219

MULTILAYER STRUCTURED SPUN YARN, PROCESS FOR PRODUCING THE SAME, AND, FABRICATED FROM THE YARN, HEAT-RESISTANT FABRIC AND HEAT-RESISTANT PROTECTIVE SUIT  

UK PubMed Central (United Kingdom)

A multilayer structured spun yarn (C) comprising a core fiber (A) and, covering the circumference thereof, a cover fiber (B). The core fiber (A) is used in an amount of 20 to 50 wt.% while the cover fiber (B) is used in an amount of 50 to 80 wt.%. The core fiber (A) consists of a para aramid fiber and is in the form of a twisted stretch broken yarn. The cover fiber (B) contains a flame retardant acrylic fiber, polyether imide fiber or meta aramid fiber. The stretch broken yarn has a twist direction identical with that of the multilayer structured yarn. The number of twists of the multilayer structured yarn (C) is 1.2 to 1.6 times that of the stretch broken yarn. The heat-resistant fabric utilizes the above multilayer structured spun yarn. The heat-resistant protective suit utilizes the above heat-resistant fabric.

TAKAHASHI MASANOBU; TASAKI KEITA; TANIMOTO YUKIMASA

220

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

Energy Technology Data Exchange (ETDEWEB)

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

NONE

1999-03-01

 
 
 
 
221

Carburization of heat resistant austenitic FeNiCr steel at 850 - 1000{sup o}C  

Energy Technology Data Exchange (ETDEWEB)

This doctoral thesis discusses carburization in FeNiCr steel. Carburization is a corrosion process involving dissolution and diffusion of carbon into the alloy. It is often found in industrial processes involving high temperatures and carbon containing gases, such as thermal cracking of mixtures of propane, butane and water vapour to form ethylene. In this work, carburization of three heat resistant FeNiCr steels in mixtures of CH{sub 4}+H{sub 2} in the temperature interval 850-1000{sup o}C was studied by thermogravimetry and different solid state characterization techniques. The process involved carbon deposition on the outer surface of the alloy, dissolution and diffusion of carbon into the alloy as well as carbide formation. The rate determining step was diffusion of carbon into the alloy. Two models based on Fick`s 2. law were applied to the results. Wagner`s model for internal oxidation, which gives an analytical solution of Fick`s 2. law, did not fit the results. A good fit was obtained basing the model on a finite difference technique. This model solves Fick`s 2. law numerically. However, the kinetic and thermodynamic data obtained by fitting deviate from those found in the literature. Cavities more or less filled with graphite and Fe particles were found just beneath the outer surface of the alloys. The formation of these cavities are attributed to a reaction between the outer Fe-rich regions of (Cr,Fe){sub 7}C{sub 3} and carbon in solid solution to form Fe and graphite and is a type of metal dusting. 137 refs., 74 figs., 19 tabs.

Forseth, S.

1995-12-01

222

Heat-resistant explosives under borehole conditions. Termostoikiye vzryvchatyye veshchestva v usloviyakh glubokikh skvazhin  

Energy Technology Data Exchange (ETDEWEB)

Presented are the results of experimental and theoretical investigation of the heat stability of heat resistant explosives intended for use in firing equipment. Defined are the boundaries of the temperature and time interval of safe use of explosives under borehole conditions depending on a number of factors (size and geometry of charges, conditions of heat exchange, effect of increased hydrostatic pressure and flushing fluid). The book has 5 chapters: I) Conditions of application of heat-resistant explosives in borehole equipment, II) Effect of different factors on heat stability of heat-resistant explosives, III) Thermal explosion under conditions of the effect of the pressure of the enclosing medium. IV) Connection between thermostability and explosive characteristics of heat-resistant explosives, V) Practical recommendations on the use of explosives in firing equipment used in deep boreholes.

1981-01-01

223

Influence of transparence of heat-resistant coatings on the thermal regime of constructions  

Science.gov (United States)

We present a computational-experimental method and the results of investigating the influence of transparence to solar radiation of the heat-resistant coating on the thermal regime of the space-vehicle construction in orbital flight.

Paderin, L. Ya.; Prusov, B. V.; Tokarev, O. D.

2010-11-01

224

Using heat resistant concrete for construction of coking batteries - an urgent problem  

Energy Technology Data Exchange (ETDEWEB)

Reviews experience in using heat resistant concrete for construction and repair of coke oven batteries in Eastern and Western Europe. Emphasis is placed on types of heat resistant concrete developed and tested in USSR, their composition and possibilities of using them for construction and repair of coking batteries, e.g. as gunite to cover worn coke chamber walls. It is suggested that the tested types of heat resistant concrete are characterized by approximately similar decrease in strength during heating. Aluminous cement (500) used as a binder is inferior to other binders, as strength of the concrete starts to decrease at 300 C. The heat resistant concrete with the highest strength is produced from pumice-stone slag and pieces of chamotte bricks with the binder consisting of furnace slag-alkali with waterglass. This concrete is characterized by high strength increasing gradually up to 500 C. (5 refs.) (In Russian)

Sibilev, A.I.; Sagalevich, Yu.D.; Zborshchik, M.P.

1980-05-01

225

Use of heat-resistant concretes for construction of coke ovens for pitch and metallurgical coke  

Energy Technology Data Exchange (ETDEWEB)

Results are evaluated of long-term tests of a new type of large block used for construction of coke ovens for production of pitch and metallurgical coke in the USSR. Blocks weighing 3000 kg were made of four types of heat-resistant concretes on the basis of Portland cement sodium silicate and sodium fluorosilicate mixed with chamotte sand, chamotte gravel and other components. Operation of coke ovens made of the heat-resistant concrete was analyzed under operational conditions for over 20 years. Analyses showed that elements made of heat-resistant concrete are characterized by lower wear and deformation and longer service life than conventional elements. Coke ovens made of heat-resistant concrete have a longer service life and reduced wear. Building coke ovens with large construction elements is more economic; labor productivity in coke oven construction and repair is also higher. 5 refs.

Sibilev, A.I.; Gordienko, A.K.; Lukin, N.E.; Titov, A.G.; Dorofeev, A.Kh.; Bort, P.I.; Zborshchik, M.P.; Parfenyuk, A.S.; Veretel' nik, S.P.; Purgin, A.K.; Zamyatin, S.R.; Perepelitsin, V.P.

1986-12-01

226

Retrofitting of superheated steam tubes requires dissimilar metal welds consisting of heat-resistant 9-12% Cr steels and low-alloy CrMo(V) so(V) steels; Sanierungsmassnahmen an Heissdampfleitungen erfordern Mischschweissverbindungen aus warmfesten 9-12% Cr-Staehlen und niedriglegierten CrMo(V)-Staehlen  

Energy Technology Data Exchange (ETDEWEB)

The weld P91/10CrMo910 is the case reported, analysed for type and distribution of the precipitates in the carburization and decarburization zone. The microhardness curve gives additional information on the extension of this zone in the weld. In the course of retrofitting measures, there will remain the necessity to make dissimilar metal weldments joining high-alloyed 9-12% chromium steels and 14 MoV63 material. For this purpose, the 15CrMoV510 proved to be better than the 10CrMo910, not only due to its higher fatigue strength, but also because it offers a more favourable range of tempering temperatures. So there will be no problems in making dissimilar welds both with the material 12MoV63 and the steels X20CrMoV121 and P91. (orig./MM) [Deutsch] Am Beispiel der Verbindung P91/10CrMo910 wurde Art und Verteilung der Ausscheidungen im Bereich der Entkohlungs- und Aufkohlungszone naeher untersucht. Der Verlauf der Mikrohaerte liefert zusaetzliche Informationen ueber die Breite dieser Zone in der Schweissverbindung. Im Rahmen von Sanierungsmassnahmen werden auch kuenftig Anschluesse zwischen hochlegierten 9-12% Chromstaehlen und 14MoV63 notwendig sein. Hier bietet sich der 15CrMoV510 im Vergleich zum 10CrMo910 als bessere Alternative an. Nicht nur auf Grund seiner hoeheren Zeitstandfestigkeit, sondern auch wegen der guenstigen Spanne der Anlasstemperatur. Dadurch sind problemlos Verbindungen sowohl zum 14MoV63 als auch zu den Staehlen X20CrMoV121 und P91 moeglich. (orig./MM)

Melzer, B. [Siempelkamp Pruef- und Gutachter-GmbH, Dresden (Germany); Oehmigen, H.G. [vom hagen mce GmbH, Bochum (Germany)

1996-12-31

227

Heat treatment of nickel alloys  

International Nuclear Information System (INIS)

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

1975-01-01

228

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

International Nuclear Information System (INIS)

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

1980-01-01

229

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

International Nuclear Information System (INIS)

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

1992-05-01

230

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

Energy Technology Data Exchange (ETDEWEB)

When welding Hastelloy G-30, secondary phases form in the weld metal. These phases cause the weld metal to be preferentially attacked in nitric acid (HN0{sub 3}) solutions contaminated with minor amounts of hydrofluoric acid (HF). A post weld solution anneal and water quench is necessary to assure that these phases redissolve into the solid. When a post weld solution anneal and water quench is not feasible, improved corrosion resistance can be obtained by welding with INCO 72 weld wire. When welding Hastelloy G-30 with INCO 72, there can be a region at the weldmetal/base-metal interface that does not benefit from the INCO 72 weld wire. This region consists of melted and resolidified Hastelloy G-30. This unmixed zone can be preferentially attacked in HN03 solutions contaminated with minor amounts of HF. Long term corrosion immersion tests have shown that the rate of attack at the weld-metal/base-metal interface can be as high as 50 mpy. Welding techniques that increase the mixing of the melted Hastelloy G-30 with the INCO 72 weld wire can reduce the interface corrosion rate.

Norby, B.C.

1992-03-03

231

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

International Nuclear Information System (INIS)

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

1975-11-16

232

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

Science.gov (United States)

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

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

2013-06-01

233

Heat resistance of Byssochlamys nivea, Byssochlamys fluva and Neosartorya fishcheri isolated from canned tomato paste.  

UK PubMed Central (United Kingdom)

Cultures of heat resistant molds (20) were isolated from spoiled canned tomato paste in order to estimate the pasteurization efficiency applied to commercially canned products. Ascospores of nine strains grown on malt extract agar for 30 days at 30 degrees C, survived heating at 85 degrees C for 20 min when initial numbers were near 10(5)/mL. Of these heat resistant strains were identified: two Byssochlamys nivea, three Byssochlamys fulva and four Neosartorya fischeri strains. Ascospores of all cultures were more heat resistant in tomato juice than in phosphate buffer. Thermal death rate curves were nonlogarithmic but approached logarithmic death rates at higher temperatures. The thermal destruction time for 1 log10 at 90 degrees C was 1.5 min for a Byssochlamys nivea strain, 8.1 min for a Byssochlamys fulva strain and 4.4 to 6.6 min for Neosartorya fischeri strains.

Kotzekidou P

1997-04-01

234

MULTILAYER STRUCTURED SPUN YARN, PROCESS FOR PRODUCING THE SAME, AND, FABRICATED FROM THE YARN, HEAT-RESISTANT FABRIC AND HEAT-RESISTANT PROTECTIVE SUIT  

UK PubMed Central (United Kingdom)

The multilayer-structured spun yarn of the present invention is a multilayer-structured spun yarn C composed of a core fiber A and a cover fiber B that wraps around the core fiber the core fiber A is in a range of 20 to 50 wt % the cover fiber B is in a range of 50 to 80 wt % the core fiber A contains a para-aramid fiber and is a stretch breaking twist yarn the cover fiber B contains a flame-retardant acrylic fiber, a polyetherimide fiber, or a meta-aramid fiber the direction of twist of the stretch breaking yarn and the direction of twist of the multilayer-structured yarn are the same and the multilayer-structured yarn C has a twist number 1.2 to 1.6 times greater than that of the stretch breaking yarn. The heat-resistant textile of the present invention uses the aforementioned multilayer-structured spun yarn. The heat-resistant protective suit of the present invention uses the aforementioned heat-resistant textile.

TAKAHASHI MASANOBU; TASAKI KEITA; TANIMOTO YUKIMASA

235

MULTILAYER STRUCTURED SPUN YARN, PROCESS FOR PRODUCING THE SAME, AND, FABRICATED FROM THE YARN, HEAT-RESISTANT FABRIC AND HEAT-RESISTANT PROTECTIVE SUIT  

UK PubMed Central (United Kingdom)

The multilayer-structured spun yarn of the present invention is a multilayer-structured spun yarn C composed of a core fiber A and a cover fiber B that wraps around the core fiber the core fiberAis in a range of 20 to 50 wt% the cover fiber B is in a range of 50 to 80 wt% the core fiber A contains a para-aramid fiber and is a stretch breaking twist yarn the cover fiber B contains a flame-retardant acrylic fiber, a polyetherimide fiber, or a meta-aramid fiber the direction of twist of the stretch breaking yarn and the direction of twist of the multilayer-structured yarn are the same and the multilayer-structured yarn C has a twist number 1.2 to 1.6 times greater than that of the stretch breaking yarn. The heat-resistant textile of the present invention uses the aforementioned multilayer-structured spun yarn. The heat-resistant protective suit of the present invention uses the aforementioned heat-resistant textile.

TAKAHASHI MASANOBU; TASAKI KEITA; TANIMOTO YUKIMASA

236

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

Science.gov (United States)

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

Tournas, V

1994-01-01

237

Electroslag welding of large diameter tubes of heat resisting chromium-molybdenum-vanadium steels  

International Nuclear Information System (INIS)

The results are presented of comparative mechanical tests of welds of large-diameter pipes from warm-resistant 15Kh1M1F steel performed by electroslag and automatic submerged arc welding with the use of 08KhMF filler wire. It is shown that electroslag welding is a most efficient technique where welds are normalized and tempered, no pre-welding heating being required. The coefficient of heat resistance of welds is 0.8. Electroslag welding of pipes with the use of a filler wire of a composition similar to that of the base metal will result in welds of a coefficient of heat resistance close to unity

1978-01-01

238

Development of 11CrMoWCo heat resistant steel for fossil thermal plants  

Energy Technology Data Exchange (ETDEWEB)

The authors have developed a 11%Cr ferritic heat resistant steel, named NF12, which has good high temperature creep strength compared with conventional heat resistant steels. The representative chemical composition of NF12 consists of 11% chromium, 2.6% tungsten, and about 2% cobalt. Its extrapolated creep rupture strength reaches about from 1.6 to 1.9 times as high as that of Modified 9Cr-1Mo steel. The estimated creep properties depends on the estimation methods. 7 refs., 10 figs., 2 tabs.

Ohgami, M.; Hasegawa, Y.; Naoi, H.; Fujita, T. [Nippon Steel Corporation, Chiba (Japan). Steel Research Labs.

1997-09-01

239

Metallurgical aspects in long term creep rupture strength properties of heat resistant steels  

Energy Technology Data Exchange (ETDEWEB)

The recent activities of long-term creep and creep rupture studies on heat resistant steels in the NRIM Creep Data Sheet Project are described. The long-term creep strain behavior described by creep rate curves and the microstructural evolution during creep have been systematically investigated for principal ferritic and austenitic heat resistant steels. The creep rate curves of engineering steels usually exhibit complicated shapes and there is substantially no steady-state region, especially at low stresses and long times. The long-term creep deformation behavior has been shown to be complicated at long times, reflecting complicated microstructural evolution during creep. (orig.)

Abe, F.; Irie, H.; Yagi, K.

1999-07-01

240

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.).

1991-01-01

 
 
 
 
241

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)

2010-07-06

242

Magnium microalloying of heat resistant nickel alloys and passivation of the condensate on vacuum induction remelting  

International Nuclear Information System (INIS)

[en] A study was made on the mechanism of liquid metal saturation with magnesium in 300 heats, conducted in vacuum induction furnaces of 1t and 2.5t capacity. The process is described by the differential equation of the first order. This testifies to diffusion character of metallic melt saturation with magnesium during vacuum induction remelting. This equation can be used for determination of magnesium content in KhN45MVTYuBR, KhN50VMTYuB and similar steels. Stabilization of magnesium content within the limits of 0.005-0.008% improves the quality of above-mentioned steels

1993-01-01

243

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

Energy Technology Data Exchange (ETDEWEB)

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

244

Statistical alloy design for superalloy. ; Especially quantitative estimation of physical properties. chotainetsu gokin no tokeiteki shuho ni yoru gokin sekkei. ; Tokuni butsuriteki seishitsu no teiryoteki yosoku ni tsuite  

Energy Technology Data Exchange (ETDEWEB)

The statistical design method of heat resistant superalloys was studied. The data on both mechanical and physical properties of 50 kinds of Ni-base heat resistant superalloys were compiled from publications of alloy manufacturers and technical handbooks. Quantitatively predictive equations of superalloy properties were derived by regression analysis with independent variables of alloy compositions as Co and Ti and dependent variables of mechanical and physical properties. The statistical alloy design program was then derived to select the most suitable alloy compositions for target heat resistant superalloys. The composition of new Ni-base heat resistant superalloy was selected for gas turbine combustor material through the program, and the thermal conductivity, coefficient of thermal expansion and dynamic modulus of elasticity were measured of the 0.5 mm plate made of such alloy. As a result, measured values well agreed with values estimated by the program resulting in the high applicability of this method. 6 refs., 4 figs., 1 tab.

Tsuji, I. (Mitsubishi Heavy Industries, Ltd., Tokyo (Japan))

1991-05-27

245

Heat Resistant Plastic Honeycomb for Sandwich Construction Based on Polyaromatic Resin.  

Science.gov (United States)

A heat resistant, glass fabric base, plastic honeycomb was fabricated to a nominal 6 lbs/cu. ft. density. Stabilized flatwise compressive strength and modulus were determined in air at room temperature, at 500, 600, 700, 900 and at 1000 F after 1/3 hour a...

W. T. Jackson B. R. Garrett

1965-01-01

246

Incidence and Diversity of Potentially Highly Heat-Resistant Spores Isolated at Dairy Farms  

Digital Repository Infrastructure Vision for European Research (DRIVER)

The presence of highly heat-resistant spores of Bacillus sporothermodurans in ultrahigh-temperature or sterilized consumer milk has emerged as an important item in the dairy industry. Their presence is considered undesirable since they hamper the achievement of commercial sterility requirements. By ...

Scheldeman, Patsy; Pil, Annelies; Herman, Lieve; De Vos, Paul; Heyndrickx, Marc

247

A summary of research on heat resistant fabrics for protective clothing  

Energy Technology Data Exchange (ETDEWEB)

Reference is made to research on the performance of heat-resistant safety fabrics. General requirements for fabrics used for thermal protection are discussed, and laboratory methods of testing are summarized. A need is seen for a specific programme to evaluate the suitability of the variety of fabrics that might be used in industrial safety apparel.

Brewster, E.P.; Barker, R.L.

1983-02-01

248

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This paper presents a system for estimating the condition of the heat resistant lining in an electrical reduction furnace for ferrosilicon. The system uses temperature measured with thermocouples placed on the outside of the furnace-pot. These measurements are used together with a mathematical model...

Jan G. Waalmann

249

Polypeptide Composition of Urea- and Heat-Resistant Mutants of Poliovirus Types 1 and 2  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Five urea-resistant and two heat-resistant mutants of poliovirus types 1 and 2 were isolated and their structural and nonstructural polypeptides compared to those of their wild-type, parental strains in an attempt to correlate mutant phenotypes with alterations in specific capsid polypeptides. Four ...

Fennell, Robert; Phillips, Bruce A.

250

Incidence of Heat-Resistant Molds in Eastern Orchards and Vineyards 1  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Over 70% of the samples of fruit, vegetation, and soil obtained in surveys of New York orchards and vineyards were contaminated with heat-resistant molds. The counts generally were low, under one per gram. Byssochlamys fulva was the most common isolate. Other isolates were identified as B. nivea, Pa...

Splittstoesser, D. F.; Kuss, F. R.; Harrison, Wanda; Prest, Dorothy B.

251

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 a...

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

252

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

253

Characterization of heat resistant mutant strains of Rhizobium sp. [Cajanus] for growth, survival and symbiotic properties  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Fourteen heat resistant mutant strains were isolated from a wild-type strain (PP201, Nod+ Fix+) of Rhizobium sp. (Cajanus) by giving it a heat shock of 43°C. These mutant strains showed a greater increase in optical density (O.D.) and a higher viable cell count in both rhizospheric and non-rhizosphe...

Nehra, Kiran; Yadav, Attar S.; Sehrawat, Anita R.; Vashishat, R. K.

254

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

255

Compatible solutes contribute to heat resistance and ribosome stability in Escherichia coli AW1.7.  

UK PubMed Central (United Kingdom)

This study investigated the mechanisms of heat resistance in Escherichia coli AW1.7 by quantification of cytoplasmic solutes, determination of ribosome denaturation, and by determination of protein denaturation. To assess the contribution of heat shock proteins and compatible solutes, experiments were conducted after exposure to sublethal heat shock, and with cultures grown at NaCl concentrations ranging from 0 to 6%. Heat resistance of E. coli AW1.7 was compared to the heat sensitive E. coli GGG10 and a plasmid-cured, heat sensitive derivative of E. coli AW1.7 named E. coli AW1.7?pHR1. Sublethal heat shock improved survival at 60°C of E. coli GGG10 and AW1.7?pHR1 but not of E. coli AW1.7. Addition of NaCl increased the heat resistance of all three strains, but only E. coli AW1.7 exhibited high heat resistance when grown in NaCl concentrations ranging from 2 to 6%. E. coli AW1.7 and GGG10 accumulated 16.1 ± 0.8 and 8.8 ± 0.8mmolL?¹ amino acids when grown at 0% NaCl, and 1.47 ± 0.07 and 0.78 ± 0.06mmolL?¹ carbohydrates when grown at 6% NaCl, respectively. Ribosome denaturation was determined by differential scanning calorimetry. After growth in the presence of 0% NaCl, the 30S subunit denatured at 63.7 ± 0.8°C and 60.7 ± 0.3°C in E. coli AW1.7 and GGG10, respectively. Fourier-transformed-infrared-spectroscopy did not indicate differences in protein denaturation between the strains during heating. In conclusion, heat resistance in E. coli AW1.7 correlates to ribosome stability at 60°C and is dependent on accumulation of cytoplasmic solutes.

Pleitner A; Zhai Y; Winter R; Ruan L; McMullen LM; Gänzle MG

2012-12-01

256

Oxidability of certain cast and sintered alloys on the base of TiAl, NiAl and Ni3Al intermetallides  

International Nuclear Information System (INIS)

[en] TiAl, NiAl, Ni3Al produced by the methods of power metallurgy and casting are studied for heat-resistance and strength. It is stated that the heat-resistance and strength of TiAl produced by the powder metallurgy method is lower than those of the cast one. The heat-resistance of the powdered Ni3Al is similar to the heat-resistance of the cast one at 1000 deg C, but its strength is higher. Yttrium microalloying of TiAl as well as molybdenum alloying of Ni3Al appreciably decreases the oxidation rate of intermetallides mentioned above

1987-01-01

257

Transport properties of MgB2 films grown on Hastelloy tape: Substrate temperature effect  

Science.gov (United States)

We report on the transport properties of MgB2 films that were directly grown on Hastelloy tapes by using a hybrid physical chemical deposition method. The substrate temperatures was varied from 480 °C to 540 °C in 20 °C increment while the deposition time and the gas mixing ratio were kept constant at 10 min and H2:B2H6 = 70:30, respectively. Within this window of substrate temperature, all the samples except the one grown at 480 °C exhibited critical current densities, J c , much higher than those observed in MgB2 wires and tapes that were made by using the powder method. For instance, the film grown at 500 °C exhibited a value of J c exceeding 3 × 105 A/cm2 at 4 T and 5 K measured in magnetic fields applied perpendicular to the substrate. In the samples grown at temperatures above 500 °C, a resistance dip was observed in the same field orientation, which can be regarded as evidence for strong flux pinning.

Kim, Dong-Ho; Park, Young-Soon; Hwang, Tae-Jong; Ranot, Mahipal; Kang, Won-Nam; Chung, Kook-Chae

2013-01-01

258

High temperature oxidation of NiAl alloys with the addition of 3d transition elements  

Energy Technology Data Exchange (ETDEWEB)

The heat resistance of NiAl alloys with the addition of 3d transition elements (titanium, vanadium, chromium, manganese, iron, cobalt, copper) has been studied at temperatures of 1373, 1473 and 1573 K. The oxidation kinetics are shown to be described by G/sup 2/=ktau, with the diffusion of atoms in the suboxide layer being the limiting process at higher temperatures. Modifying additions of titanium, chromium, iron, cobalt (1 wt.%) are shown to stabilize the oxidation resistance both of the stoichiometric NiAl composition and of solid solutions of nickel in NiAl. An increase in the amount of the additive (especially if it replaces aluminium in the alloy) impairs the heat resistance of the alloys. Alloys with vanadium are characterized by catastrophic oxidation. The interrelation between the substructure of alloys and the variation in heat resistance is discussed.

Allaverdova, N.V.; Kucherenko, L.A.; Portnoy, V.K.; Sokolovskaya, Y.M.

1985-12-16

259

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

260

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

UK PubMed Central (United Kingdom)

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

Palop A; Raso J; Pagán R; Condón S; Sala FJ

1999-02-01

 
 
 
 
261

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

Science.gov (United States)

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

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

1999-02-18

262

Heat-resistance characteristics of ascospores of Eurotium chevalieri isolated from apricot juice.  

UK PubMed Central (United Kingdom)

A heat-resistant fungus was isolated from aseptically packaged apricot pulp. The fungus was identified as Eurotium chevalieri. Heat resistance of the fungus was studied at four different temperatures (70, 75, 80 and 83 degrees C) after activation of its ascospores for 30 min at 70 degrees C. D70, D75, D80 and D83 values of ascospores of Eurotium chevalieri were estimated by linear regression (log-survival vs. heating time) as 118.58, 34.15, 5.50 and 3.77 min, respectively. The z-value was determined in the same way (regression of log-D values vs. heating temp.) and was found as 8.23 degrees C.

Kocakaya Yildiz A; Coksöyler N

2002-02-01

263

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

UK PubMed Central (United Kingdom)

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.

Karpets IuV; Kolupaev IuE; Iastreb TO; Dmitriev AP

2012-11-01

264

Synthesis of heat-resistant SiC fiber by radiation processing  

International Nuclear Information System (INIS)

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

1992-01-01

265

Ordered mesoporous silica materials (SBA-15) with good heat-resistant magnetism  

Energy Technology Data Exchange (ETDEWEB)

A series of highly ordered mesoporous materials (CF-SBA-15) with heat-resistant magnetism have been successfully prepared from impregnation of cobalt salt, iron salt, and citric acid with as-synthesized SBA-15. XRD and N{sub 2} isotherms indicate that these materials have highly ordered hexagonal mesoporous symmetry and open pore systems. The measurement of magnetic property shows that these materials are ferromagnetic even if calcined at 550 deg. C for 10 h in air, indicating their good heat-resistant magnetism. These results would be very important for recycle and regeneration of adsorbents and catalysts in practical applications. Moreover, this method may be useful for other mesoporous materials with thermally stable magnetism from a combination of other mesoporous materials such as MCM-41 with magnetic nanoparticles of MnFe{sub 2}O{sub 4} and NiFe{sub 2}O{sub 4}.

Du Yunchen; Liu Sen; Ji Yanyan; Zhang Yonglai; Xiao Ni [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry and College of Chemistry, Jilin University, Changchun 130012 (China); Xiao Fengshou [State Key Laboratory of Inorganic Synthesis and Preparative Chemistry and College of Chemistry, Jilin University, Changchun 130012 (China)], E-mail: fsxiao@mail.jlu.edu.cn

2008-07-15

266

Heat resistance of Saccharomyces cerevisiae strains isolated from spoiled peach puree.  

UK PubMed Central (United Kingdom)

The heat resistance of three Saccharomyces cerevisiae strains isolated from spoiled peach puree, in McIlvaine buffer (pH 4 and 7) and peach puree (pH 3.9) was studied. The D60-values in buffer at pH 7 were 0.75, 1.32 and 0.14 min for the strains 173, 180 and 325, respectively. The pH of the buffer did not influence the heat resistance of the three strains studied. The thermal sensitivity for all strains assayed was higher when peach puree was used with D60-values of 0.53, 0.20 and 0.10 min for the strains 173, 180 and 325, respectively. The menstrua used had limited influence on the z-values, varying between 3 (strain 173, pH 4) and 4 (strain 325, peach puree).

Garza S; Teixidó JA; Sanchis V; Viñas I; Condón S

1994-10-01

267

Heat resistance of Saccharomyces cerevisiae strains isolated from spoiled peach puree.  

Science.gov (United States)

The heat resistance of three Saccharomyces cerevisiae strains isolated from spoiled peach puree, in McIlvaine buffer (pH 4 and 7) and peach puree (pH 3.9) was studied. The D60-values in buffer at pH 7 were 0.75, 1.32 and 0.14 min for the strains 173, 180 and 325, respectively. The pH of the buffer did not influence the heat resistance of the three strains studied. The thermal sensitivity for all strains assayed was higher when peach puree was used with D60-values of 0.53, 0.20 and 0.10 min for the strains 173, 180 and 325, respectively. The menstrua used had limited influence on the z-values, varying between 3 (strain 173, pH 4) and 4 (strain 325, peach puree). PMID:7848782

Garza, S; Teixidó, J A; Sanchis, V; Viñas, I; Condón, S

1994-10-01

268

Crack growth in metallic alloys  

International Nuclear Information System (INIS)

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

1980-01-01

269

New heat-resistant chromium steels for a promising objects of power engineering  

Science.gov (United States)

Data are presented on new-grade 12Kh10M1V1FBR and 10Kh9V2MFBR heat-resistant chromium steels for turbine rotors, boiler tube systems, and pipelines of ultrasupercritical steam parameters. The operating properties of new steels are assessed in comparison with those of 12Kh1MF, 15Kh1M1F, and 10Kh9MFB steels.

Dub, A. V.; Skorobogatykh, V. N.; Shchenkova, I. A.

2008-07-01

270

Development of a Heat-Resistant Neutron Shielding Resin for the National Centralized Tokamak  

Science.gov (United States)

A 300°C heat-resistant neutron shielding material was newly developed. The material consists of phenol-based resin with 5 weight-% boron. The neutron shielding performance of the developed resin, which was examined by usinga 252Cf neutron source, was almost identical to that of polyethylene. The resin can be applied to the port section of the vacuum vessel of the DD plasma device to suppress the streaming neutrons and to reduce the nuclear heating of thesuperconducting coils.

Morioka, Atsuhiko; Sakurai, Shinji; Okuno, Koichi; Tamai, Hiroshi

271

Creep and creep rupture behaviour of heat resistant steels under variable loading conditions  

Energy Technology Data Exchange (ETDEWEB)

The creep and creep rupture behaviour under rectangular cylindrical conditions was measured on 8 typical heat resistant steels up to 35 000 h test duration. The results are described by the modified life fraction rule. The main dependencies of the characteristic of that rule, the relative life, are investigated. Concepts for the evaluation of the relative life are presented in regard to design and supervision of components.

Kloos, K.H.; Granacher, J.; Kooy, A.

1987-11-01

272

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

Science.gov (United States)

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

Huang, Song; Chen, Xiao Dong

2013-05-09

273

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

UK PubMed Central (United Kingdom)

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

Huang S; Chen XD

2013-07-01

274

Evaluation of the strain variability of Salmonella enterica acid and heat resistance.  

UK PubMed Central (United Kingdom)

The inherent acid and heat resistances of 60 Salmonella enterica strains were assessed in tryptone soy broth without dextrose acidified to pH 3.0 or heated at 57 °C. A total of 360 inactivation curves were generated. Regarding the acid challenge experiments, the inactivation rate (kacid), estimated using the log-linear model, ranged from 0.47 to 3.25 h(-1). A log-linear model with a "survival tail" was used to describe the thermal inactivation of the strains, and the estimated inactivation rate (kheat) ranged from 0.42 to 1.33 min(-1). The strain variability of kacid was considerably higher than that of kheat with the coefficient of variation of this kinetic parameter among the tested strains being 39.0% and 18.3%, respectively. No correlation was observed between the estimated kacid and kheat values of the 60 S. enterica strains. Furthermore, no trends among the tested strains related to origin, serotype or antibiotic resistance profile were evident. The present study is the first one to comparatively evaluate the inherent acid and heat resistance profiles of multiple S. enterica strains. Beyond their value in strain selection for use in food safety challenge studies, the collected data should be useful in describing and integrating the strain variability of S. enterica acid and heat resistance profiles in quantitative microbial risk assessment.

Lianou A; Koutsoumanis KP

2013-06-01

275

Method for identifying heat-resistant fungi of the genus Neosartorya.  

UK PubMed Central (United Kingdom)

Species of the genus Neosartorya are heat-resistant fungi that cause the spoilage of heat-processed acidic foods due to the formation of heat-resistant ascospores, and they produce mycotoxins, such as fumitremorgins and gliotoxin. Their anamorphs are phylogenetically and morphologically very close to Aspergillus fumigatus, which has never been reported as a spoilage agent in heat-processed food products. Therefore it is important to discriminate between the species of Neosartorya and A. fumigatus in the food industry. In the present study, we examined ?-tubulin and calmodulin genes to identify Neosartorya and A. fumigatus at the species level and found a region for specifically detecting these species. We succeeded in developing the PCR method of differentiating and identifying Neosartorya and A. fumigatus using specific primer sets. Moreover, we developed specific primer sets to identify Neosartorya species, N. fischeri, N. glabra, N. hiratsukae, N. pseudofischeri, and N. spinosa-complex, which are important in food spoilage; these fungi vary in heat resistance and productivity of mycotoxins, depending on the species. PCR using these primer sets did not detect other fungi involved in food spoilage and environmental contamination. These identification methods are rapid and simple with extremely high specificity.

Yaguchi T; Imanishi Y; Matsuzawa T; Hosoya K; Hitomi J; Nakayama M

2012-10-01

276

Method for identifying heat-resistant fungi of the genus Neosartorya.  

Science.gov (United States)

Species of the genus Neosartorya are heat-resistant fungi that cause the spoilage of heat-processed acidic foods due to the formation of heat-resistant ascospores, and they produce mycotoxins, such as fumitremorgins and gliotoxin. Their anamorphs are phylogenetically and morphologically very close to Aspergillus fumigatus, which has never been reported as a spoilage agent in heat-processed food products. Therefore it is important to discriminate between the species of Neosartorya and A. fumigatus in the food industry. In the present study, we examined ?-tubulin and calmodulin genes to identify Neosartorya and A. fumigatus at the species level and found a region for specifically detecting these species. We succeeded in developing the PCR method of differentiating and identifying Neosartorya and A. fumigatus using specific primer sets. Moreover, we developed specific primer sets to identify Neosartorya species, N. fischeri, N. glabra, N. hiratsukae, N. pseudofischeri, and N. spinosa-complex, which are important in food spoilage; these fungi vary in heat resistance and productivity of mycotoxins, depending on the species. PCR using these primer sets did not detect other fungi involved in food spoilage and environmental contamination. These identification methods are rapid and simple with extremely high specificity. PMID:23043829

Yaguchi, Takashi; Imanishi, Yumi; Matsuzawa, Tetsuhiro; Hosoya, Kouichi; Hitomi, Jun; Nakayama, Motokazu

2012-10-01

277

The effect of recovery conditions on the apparent heat resistance of Bacillus cereus spores.  

Science.gov (United States)

The effect of recovery media and incubation temperature on the apparent heat resistance of three ATCC strains (4342, 7004 and 9818) of Bacillus cereus spores were studied. Nutrient Agar (NA), Tryptic Soy Agar (TSA), Plate Count Agar (PCA) and Milk Agar (MA) as the media and temperatures in the range of 15-40 degrees C were used to recover heated spores. Higher counts of heat injured spores were obtained on PCA and NA. The optimum subculture temperature was about 5 degrees C below the optimum temperature for unheated spores. No significant differences in heat resistance were observed with the different recovery conditions except for strains 4342 and 9818 when MA was used as plating medium. Large differences in D-values were found among the strains (D100 = 0.28 min for 7004; D100 = 0.99 min for 4342; D100 = 4.57 min for 9818). The 7004 strain showed a sub-population with a greater heat resistance. The z values obtained for the three strains studied under the different recovery conditions were similar (7.64 degrees C +/- 0.25). PMID:7759384

Gonzalez, I; Lopez, M; Mazas, M; Gonzalez, J; Bernardo, A

1995-05-01

278

Heat resistance of Bacillus cereus spores: effects of milk constituents and stabilizing additives.  

Science.gov (United States)

Heat resistance of Bacillus cereus spores (ATCC 7004, 4342, and 9818) heated in different types of milk (skim, whole, and concentrated skim milk), skim milk containing stabilizing additives (sodium citrate, monopotassium phosphate, or disodium phosphate, 0.1%), and cream was investigated. Thermal resistance experiments were performed at temperatures within the range of 92 to 115 degrees C under continuous monitoring of pH. For strain 4342 no significant differences (P < 0.05) in D values were detected in any case. For strains 7004 and 9818 higher D values of about 20% were obtained in whole and concentrated skim milk than those calculated in skim milk. From all stabilizing additives tested, only sodium citrate and sodium phosphate increased the heat resistance for strain 9818. However, when the menstruum pH was measured at the treatment temperature, different pH values were found between the heating media. The differences in heat resistance observed could be due to a pH effect rather than to the difference in the substrates in which spores were heated. In contrast, when cream (fat content 20%) was used, lower D values were obtained, especially for strains 7004 and 9818. z values were not significantly modified by the milk composition, with an average z value of 7.95+/-0.20 degrees C for strain 7004, 7.88+/-0.10 degrees C for strain 4342, and 9.13+/-0.16 degrees C for strain 9818. PMID:10419217

Mazas, M; López, M; Martínez, S; Bernardo, A; Martin, R

1999-04-01

279

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

280

Errors in measurements by ultrasonic thickness gauges caused by the variation in ultrasonic velocity in constructional steels and metal alloys  

Energy Technology Data Exchange (ETDEWEB)

Numerical values of the variation in ultrasonic velocity in constructional metal alloys and the measurement errors related to them are systematized. The systematization is based on the measurement results of the group ultrasonic velocity made in the All-Union Scientific-Research Institute for Nondestructive Testing in 1983-1984 and also on the measurement results of the group velocity made by various authors. The variations in ultrasonic velocity were systematized for carbon, low-alloy, and medium-alloy constructional steels; high-alloy iron base alloys; nickel-base heat-resistant alloys; wrought aluminum constructional alloys; titanium alloys; and cast irons and copper alloys.

Kalinin, V.A.; Tarasenko, V.L.; Tselser, L.B.

1988-09-01

 
 
 
 
281

Hydrogen permeation through passive layers on austenitic high temperature alloys  

International Nuclear Information System (INIS)

[en] Using a sample of the high temperature alloy Hastelloy X it is shown that chromium oxide layers of a few ?m thickness reduce the permeation of hydrogen isotopes for around three orders of magnitude. Besides the permeation rate its pressure and temperature dependency serves as an indicator for the quality of an oxide barrier. For passive layers with low permeation rates the pressure exponent increases from 0.5 to 1 and the activation energy from 60-70 kJ/Mol to 130-170 kJ/Mol indicating completely different permeation mechanisms compared to the unscaled alloy. (Auth.)

1983-06-03

282

Eutectic solidification of binary alloys  

International Nuclear Information System (INIS)

The eutectic is a common multiphase metallurgical constituent. Yet all previous theories of eutectic reaction shared one shortcoming - they lacked an adequate understanding of the eutectic grain structure. Focusing on metallography, Dnepropetrovsk school of thought founded by K.P. Bunin has devised a new concept of eutectic structure formation relying on findings in solidification of Fe-, Al-, Ti-, Cu-, Zn-, Pb- and Sn-base eutectic alloys. Eutectic solidification of binary alloys has been found to occur by joint cooperative growth of finely branched dendrites of the eutectic constituents. A eutectic grain is a two-phase bicrystal whose morphology is determined by the crystallochemical nature of the eutectic's base constituent. Based on studies into genesis and morphology of eutectics, new families of eutectic-type alloys were developed, such as deformable white irons, Boralloys (high-boron wear resistant iron alloys), Ticads (heat resistant titanium-silicon alloys), and Gasars (porous metallic materials for a wide variety of applications). (author)

2000-01-01

283

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1998-07-01

284

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

Science.gov (United States)

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

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

2013-10-01

285

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

International Nuclear Information System (INIS)

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

1000-01-00

286

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2007-10-01

287

Modeling heat resistance of Bacillus weihenstephanensis and Bacillus licheniformis spores as function of sporulation temperature and pH.  

UK PubMed Central (United Kingdom)

Although sporulation environmental factors are known to impact on Bacillus spore heat resistance, they are not integrated into predictive models used to calculate the efficiency of heating processes. This work reports the influence of temperature and pH encountered during sporulation on heat resistance of Bacillus weihenstephanensis KBAB4 and Bacillus licheniformis AD978 spores. A decrease in heat resistance (?) was observed for spores produced either at low temperature, at high temperature or at acidic pH. Sporulation temperature and pH maximizing the spore heat resistance were identified. Heat sensitivity (z) was not modified whatever the sporulation environmental factors were. A resistance secondary model inspired by the Rosso model was proposed. Sporulation temperatures and pHs minimizing or maximizing the spore heat resistance (T(min(R)), T(opt(R)), T(max(R)), pH(min(R)) and pH(opt(R))) were estimated. The goodness of the model fit was assessed for both studied strains and literature data. The estimation of the sporulation temperature and pH maximizing the spore heat resistance is of great interest to produce spores assessing the spore inactivation in the heating processes applied by the food industry.

Baril E; Coroller L; Couvert O; Leguérinel I; Postollec F; Boulais C; Carlin F; Mafart P

2012-05-01

288

Investigations of ferritic/martensitic super heat resistant 11-12 %Cr steels for 650 C power plants  

Energy Technology Data Exchange (ETDEWEB)

The investigations of advanced ferritic/martensitic 11-12 %Cr steels for 650 C power plant components focus on the improvement of high-temperature creep properties with respect to chemical composition. The claim of the DFG research work was the development of new heat-resistant 12 %Cr ferritic-martensitic steels with sufficient creep and oxidation resistance for a 650 C application by using basic principles and concepts of physical metallurgy on the basis of the state of art and to overcome the usual trial and error industrial alloy development. Efforts are focussed on a 100,000h creep strength of 100MPa at 650 C in combination with a sufficient corrosion resistance by a Cr content of 12 % with contents 4-5 %W, 3.4-5,5 %Co,V, B and 1 %Cu as well as the choice of Ta or Ti instead of Nb. The results demonstrate that the aim is not to realize with the used alloying concept. In the long term range all 12 %Cr melts have a lower creep rupture strength than the advanced 9 %Cr piping steel P92. A high creep strength could be reached with a 0.06 % Ta alloyed 11 %Cr melt, which is in addition alloyed with a higher C and B content and as well as with lower W and Co portions. The results indicate in accordance with the finding of other steel researcher that a lower Cr content allows more effectiveness for the alloying partners respectively for the generation of more stable precipitates. (Abstract Copyright [2006], Wiley Periodicals, Inc.) [German] Untersuchungen an fortschrittlichen ferritisch-martensitischen 11-12 %Cr Staehlen, die in Dampfkraftwerken bis 650 C zum Einsatz kommen, konzentrieren sich auf Hochtemperaturkriecheigenschaften unter Beruecksichtigung der chemischen Zusammensetzung. Ziel des DFG-Forschungsprojekts war die Entwicklung neuer hochwarmfester ferritisch-martensitischer 12 % Cr-Staehle mit ausreichendem Kriech- und Oxidationswiderstand bis zu einer Anwendungstemperatur von 650 C. Es wurde dabei versucht, die Prinzipien und Konzepte der physikalischen Metallurgie gemaess des aktuellen Standes der Technik anzuwenden, um die herkoemmliche ''Trial and Error''-Entwicklungsmethode der industriellen Legierungsentwicklung zu ueberwinden. Das Konzept konzentrierte sich auf eine 100,000h Kriechfestigkeit von 100MPa bei 650 C in Kombination mit einer ausreichenden Oxidationsbestaendigkeit durch einen Cr-Anteil von 12 %. Weitere Legierungselemente waren 4-5 % W, 3,4-5,5 % Co, V, B und 1 % Cu sowie wahlweise Ta oder Ti als Ersatz fuer Nb. Die Ergebnisse zeigen, dass das angestrebte Ziel nicht mit der eingeschlagenen Strategie erreichbar ist. Im Langzeitbereich weisen alle 12 % Cr-Legierungen eine niedrigere Zeitstandfestigkeit auf als der bereits etablierte 9 %Cr-Rohrstahl P92, der bis ca. 620 C eingesetzt werden kann. Eine hoehere Kriechfestigkeit mit einer ausreichenden Oxidationsbestaendigkeit konnte mit einer 11 %Cr/0,006 %Ta-Schmelze erzielt werden, die darueber hinaus gegenueber den anderen Versuchsschmelzen mit mehr C und B sowie mit weniger W und Co legiert ist. Die Ergebnisse zeigen, in Uebereinstimmung mit anderen Forschungsergebnissen, dass ein geringerer Cr-Gehalt mehr Wirksamkeit fuer die Legierungspartner zur Verbesserung der Kriechfestigkeit ermoeglicht. (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Mayer, K.H. [ALSTOM Energie GmbH, Nuernberg (Germany); Scholz, A.; Wang, Y. [Institute for Materials Technology (IfW), Darmstadt University of Technology Germany, Grafenstrasse 2, 64283 Darmstadt (Germany)

2006-10-15

289

Heat resistance of histamine-producing bacteria in irradiated tuna loins.  

Science.gov (United States)

Consumption of foods high in biogenic amines leads to an illness known as histamine, or scombrotoxin, poisoning. The illness is commonly associated with consumption of fish with high levels of histamine ( $ 500 ppm). The objective of this study was to determine and compare the heat resistance of five histamine-producing bacteria in irradiated albacore tuna loins. Heat-resistance parameters (D- and z-values) were determined for Morganella morganii, Raoultella planticola, Hafnia alvei, and Enterobacter aerogenes. D- or z-values were not determined for Photobacterium damselae, which was the most heat-sensitive organism in this study. P. damselae declined > 5.9 log CFU/g after a heat treatment of 50°C for 10 min, 54°C for 3 min, and 56°C for 0.5 min. M. morganii was the most heat-resistant histamine-producing bacteria in albacore tuna loins, followed by E. aerogenes, H. alvei, and R. planticola. M. morganii and E. aerogenes had the highest D50°C, 49.7 ± 17.57 and 51.8 ± 17.38 min, respectively. In addition, M. morganii had the highest D-values for all other temperatures (54, 56, and 58°C) tested. D- and zvalues were also determined for M. morganii in skipjack tuna. While no significant (P > 0.05) difference was observed between D54°C and D56°C of M. morganii in either albacore or skipjack tuna, the D58°C (0.4 ± 0.17 min) was significantly lower (P < 0.05) in skipjack than in albacore (0.9 ± 0.24 min). The z-values for all organisms tested were in the range of 3.2 to 3.8°C. This study suggests that heat treatment designed to control M. morganii in tuna loins is sufficient for controlling histamine-producing bacteria in canned-tuna processing environments. PMID:23992506

Enache, Elena; Kataoka, Ai; Black, D Glenn; Weddig, Lisa; Hayman, Melinda; Bjornsdottir-Butler, Kristin

2013-09-01

290

Heat resistance of histamine-producing bacteria in irradiated tuna loins.  

UK PubMed Central (United Kingdom)

Consumption of foods high in biogenic amines leads to an illness known as histamine, or scombrotoxin, poisoning. The illness is commonly associated with consumption of fish with high levels of histamine ( $ 500 ppm). The objective of this study was to determine and compare the heat resistance of five histamine-producing bacteria in irradiated albacore tuna loins. Heat-resistance parameters (D- and z-values) were determined for Morganella morganii, Raoultella planticola, Hafnia alvei, and Enterobacter aerogenes. D- or z-values were not determined for Photobacterium damselae, which was the most heat-sensitive organism in this study. P. damselae declined > 5.9 log CFU/g after a heat treatment of 50°C for 10 min, 54°C for 3 min, and 56°C for 0.5 min. M. morganii was the most heat-resistant histamine-producing bacteria in albacore tuna loins, followed by E. aerogenes, H. alvei, and R. planticola. M. morganii and E. aerogenes had the highest D50°C, 49.7 ± 17.57 and 51.8 ± 17.38 min, respectively. In addition, M. morganii had the highest D-values for all other temperatures (54, 56, and 58°C) tested. D- and zvalues were also determined for M. morganii in skipjack tuna. While no significant (P > 0.05) difference was observed between D54°C and D56°C of M. morganii in either albacore or skipjack tuna, the D58°C (0.4 ± 0.17 min) was significantly lower (P < 0.05) in skipjack than in albacore (0.9 ± 0.24 min). The z-values for all organisms tested were in the range of 3.2 to 3.8°C. This study suggests that heat treatment designed to control M. morganii in tuna loins is sufficient for controlling histamine-producing bacteria in canned-tuna processing environments.

Enache E; Kataoka A; Black DG; Weddig L; Hayman M; Bjornsdottir-Butler K

2013-09-01

291

Evaluation of prefailure stages of heat-resisting steels by the eddy-current method  

Energy Technology Data Exchange (ETDEWEB)

Experiments were carried out to evaluate the possibilities of evaluating, by the nondestructive eddy current method, early stages of damage in heat-resisting chrome-molybdenum-vanadium steels used in the conditions of development of the creep deformation process. A correlation was found between the parameters of the signal of eddy current attached transducer and the degree of damage in the metal of bends of steam by-pass pipes of 12Kh1MF steel can be evaluated using, as the information-carrying parameter, the modulus of the signal of the eddy current attached transducer.

Volkov, B.I.; Agafonov, V.A.; Bologov, G.A.; Fedorov, A.L.

1988-02-01

292

Use of eddy current method for estimation of pre-fracture stage in heat resistance steels  

International Nuclear Information System (INIS)

Experimental study was made on possibility of evaluating early stages of fracture of heat resisting chromium-molybdenum-vanadium steels used under creep conditions, applying nondestructive eddy current method. The correlation between parameters of signal of eddy current superposed converter and the degree of metal damage with micropores was established. Principle possibility of estimating degree of damage for bend metal of 12Kh1MF steel steam overflow tubes when using modulus of the signal of eddy current superpose converter as informative parameter was shown.

1987-01-01

293

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

International Nuclear Information System (INIS)

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

2001-01-01

294

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

295

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

International Nuclear Information System (INIS)

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

1992-01-01

296

Purification and properties of heat-resistant exotoxin produced by Macrophomina phaseolina (Tassi) Goid in culture.  

UK PubMed Central (United Kingdom)

A partially purified preparation of a water-soluble, heat-resistant, nonspecific exotoxin produced by a strain of Macrophomina phaseolina, isolated from Phaseolus mungo L. could reduce Cu++ ions and produced a red colour with 2,4-dinitrophenyl hydrazine reagent. It caused inhibition of seed germination, wilting of cult seedlings, stunted growth of young seedlings and loss of permeability of the cell membrane. Seedlings of P. mungo, grown in presence of the toxin showed a slight increase in the contents of protein and total RNA over control, but a significant increase in the specific activities of F-1, 6-BP aldolase and G-6-P isomerase.

Siddiqui KA; Gupta AK; Paul AK; Banerjee AK

1979-09-01

297

Utilization of heat-resistance cables with mineral insulation in nuclear-power installations  

Energy Technology Data Exchange (ETDEWEB)

The survey reflects accumulated experience in utilization of heat- and radiation-resistant cables with mineral insulation in the monitoring and control system of nuclear power and research reactors, in particular as necessary component parts of intrareactor detectors. Results are reported for several investigations of electrical conductivity in mineral insulation and background effects in cables under intense irradiation and at high temperatures; data on other electrical properties of cables are also generalized. Designs of heat-resistant cables and cable shoes are described and certain technological aspects of their utilization are considered.

Emel' yanov, I.Ya.; Volod' ko, Yu.I.; Efanov, A.I.

1981-01-01

298

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

Energy Technology Data Exchange (ETDEWEB)

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.

Kwak, Dong Ho; Nam, Soo Woo [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)

2005-11-15

299

Prediction of long-term precipitate evolution in austenitic heat-resistant steels  

Energy Technology Data Exchange (ETDEWEB)

Numerical prediction of the long-term precipitate evolution in five different austenitic heat-resistant stainless steels, NF709, Super304H, Sanicro25, CF8C-PLUS and HTUPS has been carried out. MX and M{sub 23}C{sub 6} are predicted to remain as major precipitates during long-term aging in these steels. The addition of 3 wt% Cu produces very fine Cu-rich precipitates during aging in Super304H and Sanicro25. It is found that the amount of Z phase start to increase remarkably between 1,000 and 10,000 hours of aging at the expense of MX precipitates in the steels containing a high nitrogen content. However, the growth rate of Z phase is relatively slow and its average size reaches at most a few tens of nanometers after 100,000 hours of aging at 700 C, compared with 9-12% Cr ferritic/martensitic heat-resistant steels. The predicted precipitation sequence and precipitate size during aging are in general agreement with experimental observations. (orig.)

Shim, Jae-Hyeok; Jung, Woo-Sang; Cho, Young Whan [Korea Institute of Science and Technology, Seoul (Korea, Republic of). Materials/Devices Div.; Kozeschnik, Ernst [Vienna Univ. of Technology (Austria). Inst. of Materials Science and Technology

2010-07-01

300

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

Science.gov (United States)

Nanosized MX precipitates in ultra-low-carbon ferritic/martensitic heat-resistant 9Cr-W-Mo-VNbTiN steels were characterized by transmission electron microscope (TEM) using carbon film replicas. The steels were prepared by vacuum induction melting followed by hot forging and rolling into plates. The plates were normalized at 1100 °C for 1 hour, cooled in air, and tempered at 700 °C for 1 hour. The results show that bimodal nanosized MX precipitates distribute densely and homogeneously in the matrix within martensitic lath after normalizing-and-tempering heat treatment. The larger nanosized MX precipitates with the size of 30 to 50 nm are rich in Nb, while the smaller ones with the size of about 10 nm contain less Nb but more V. Small addition of Ti causes an increase in the number of the larger nanosized MX precipitates. The total number density of the nanosized MX precipitates in the ultra-low-carbon ferritic/martensitic steels is measured to be over 300/ ?m2, much higher than that in conventional ferritic/martensitic steels. Short-term creep test results show that the ultra-low-carbon ferritic/martensitic steels with high dense nanosized MX precipitates have much higher creep rupture strength than conventional ASME-P92 steel. The strength degradation of the ultra-low-carbon ferritic/martensitic heat-resistant steels during creep is also discussed in this article.

Yin, Feng-Shi; Jung, Woo-Sang

2009-02-01

 
 
 
 
301

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

2012-02-14

302

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

UK PubMed Central (United Kingdom)

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.

Wu Q; Xu Y

2012-02-01

303

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

International Nuclear Information System (INIS)

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

1984-01-01

304

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

UK PubMed Central (United Kingdom)

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

Bojer MS; Hammerum AM; Jørgensen SL; Hansen F; Olsen SS; Krogfelt KA; Struve C

2012-09-01

305

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 ß-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

306

Corrosion tests of canister and overpack materials in simulated basalt groundwater. [Hastelloy G and C-276  

Energy Technology Data Exchange (ETDEWEB)

Preliminary results indicate that the environment expected in a repository in basalt is not highly corrosive to the materials tested. Comparisons of weight change data between two simulated basalt groundwater compositions indicate that variations in oxygen fugacity had a minor effect on corrosion of nickel, titanium, and zirconium alloys. The corrosion of cupronickel alloy, however, was drastically reduced when a lower oxygen fugacity was maintained. Effectiveness of a hydrogen/argon sparge to maintain a low oxygen fugacity in a simulated groundwater was demonstrated. 5 tables.

Anderson, W.J.

1981-01-01

307

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

308

Single crystal rhenium-containing nickel alloys for turbine engine blades  

International Nuclear Information System (INIS)

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

2002-01-01

309

Development of heat resistant explosives and their laboratory and field evaluation protocol for application in fire affected mines  

Energy Technology Data Exchange (ETDEWEB)

At present, a number of coal mines in India are affected by fire leading to steady destruction of precious energy resource. The development of heat resistant explosives shall enable the coal industry to remove as much coal as possible from the hot zones in fire-affected mines and to isolate and prevent fire from spreading further because of blasting. This paper discusses the development of heat-resistant and explosives and their laboratory and field evaluation protocol for application in fire-affected mines. 6 refs., 1 fig., 4 tabs.

Sagar, P.; Patel, K.L.; Nabiullah, M. [Dept. of Scientific and Industrial Research, Technology Bhawan, New Delhi (India)

2002-07-01

310

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

Directory of Open Access Journals (Sweden)

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

Jan G. Waalmann

1988-01-01

311

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)

1992-01-01

312

Novel Hydrophilic Resin Applied in Heat-Resistant Water-Borne Coatings  

Science.gov (United States)

Poly(phthalazinone ether nitrile ketone)s (PPENK) was modified with NaOH in N,N-dimethyl acetamide (DMAc) in order to find a hydrophilic resin applied in heat-resistant water-borne coatings. The properties of hydrolyzates (HPPENK) in different hydrolysis time were characterized by FT-IR and 1H-NMR, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), contact angle (water) as well as solubility measurements. The results indicated that, along with the prolonged hydrolysis time, nitrile groups conversion ratio and glass transition temperature (Tg) of hydrolyzates increase, whereas weight loss ratio of HPPENK decreases. As expected, the hydrophilicity of HPPENK was improved greatly, e.g., when CN conversion ratio was 93.82%, the water contact angles were found to decrease from 75.3° of PPENK to 54.4° of HPPENK. HPPENKc dispersion has no separation more than 20 days in terms of shelf-life.

Liu, Z. Y.; Wang, J. Y.; Yan, Q. L.; Kou, Y.; Jian, X. G.

313

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

Directory of Open Access Journals (Sweden)

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

As?anowicz M.; O?ci?owski A.; Stacha?czyk J.; Wieliczko P.

2007-01-01

314

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; Biswas Champakali; Patnaik Rajinder

2004-01-01

315

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

316

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

Science.gov (United States)

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

Tanaka, Hitoshi; Kibayashi, Tatsuya; Niwa, Miki

2013-08-01

317

Study of alloys of refractory metals and their applications  

Energy Technology Data Exchange (ETDEWEB)

The papers presented in this volume provide an overview of recent theoretical and experimental research concerned with the physicochemical and physicomechanical properties of alloys based on refractory metals, such as rhenium, tungsten, and molybdenum. In particular, attention is given to the interaction of Re, W, and Mo with other elements of the periodic system; phase diagrams of binary, ternary, and complex alloys; and new structural types of heat-resistant compounds. The development of new alloys with special physicomechanical properties is discussed. Attention is also given to the properties of thin films of refractory alloys and the use of new materials in microelectronic devices.

Savitskii, E.M.

1983-01-01

318

Influence of spore moisture content on the dry-heat resistance of Bacillus subtilis var. niger.  

UK PubMed Central (United Kingdom)

The dry-heat resistance of Bacillus subtilis var. niger spores located in or on various materials was determined as D and z values in the range of 105 through 160 C. The systems tested included spores located on steel and paper strips, spores located between stainless-steel washers mated together under 150 inch-lb and 12 inch-lb of torque, and spores encapsulated in methylmethacrylate and epoxy plastics. D values for a given temperature varied with the test system. High D values were observed for the systems in which spores were encapsulated or under heavy torque, whereas lower D values were observed for the steel and paper strip systems and the lightly torqued system. Similar z values were obtained for the plastic and steel strip systems (z(D) = 21 C), but an unusually low z for spores on paper (z(D) = 12.9 C) and an unusually high z for spores on steel washers mated at 150 inch-lb of torque (z(D) = 32 C) were observed. The effect of spore moisture content on the D value of spores encapsulated in water-impermeable plastic was determined, and maximal resistance was observed for spores with a water activity (a(w)) of 0.2 to 0.4. Significantly decreased D values were observed for spores with moisture contents below a(w) 0.2 or above a(w) 0.4. The data indicate that the important factors to be considered when measuring the dry heat resistance of spores are (i) the initial moisture content of the spore, (ii) the rate of spore desiccation during heating, (iii) the water retention capacity of the material in or on which spores are located, and (iv) the relative humidity of the system at the test temperature.

Angelotti R; Maryanski JH; Butler TF; Peeler JT; Campbell JE

1968-05-01

319

Influence of lactate and acetate salt adaptation on Salmonella Typhimurium acid and heat resistance.  

UK PubMed Central (United Kingdom)

The aim of the present study was to determine the survival of Salmonella Typhimurium adapted with sodium lactate (NaL), potassium lactate/sodium acetate mixture (KL/NaA) or sodium acetate (NaA) in simulated gastric fluid (SGF) and during heat treatment. NaL-, KL/NaA- and NaA-adapted cells were prepared by incubating in tryptic soy broth (TSB) containing these salts at 5, 5 and 3% (w/v) concentration levels, respectively, for 24 h at 37 °C. The Baranyi model was used to compare the growth kinetic parameters of adapted cells. The acid and heat resistance of adapted cells were determined by incubating in SGF (pH 2.04) at 37 °C and in TSB at 55.8, 57.8 and 59.8 °C, respectively. Adapted cells had significantly (P < 0.05) longer lag phase duration (LPD) and slower maximum growth rate (MGR) than non-adapted cells. The acid resistance of KL/NaA-adapted cells was not significantly (P > 0.05) different from that of non-adapted cells. NaL-adapted cells were more susceptible to the low pH environment, whereas NaA-adapted cells showed enhanced acid resistance compared to non-adapted and other adapted cells. Unlike acid resistance, both NaL- and NaA-adapted cells showed enhanced heat resistance with increased D-values, regardless of treatment temperatures. Thus, this study indicates that adaptation of S. Typhimurium to 5% NaL or 3% NaA could enhance their ability to survive thermal processes or in the human stomach, possibly increasing the risk of Salmonella outbreaks.

Yuan W; Ágoston R; Lee D; Lee SC; Yuk HG

2012-06-01

320

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2006-06-15

 
 
 
 
321

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

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 si...

Sörqvist S

322

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...

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

323

Taxonomy of Clostridium bifermentans and Clostridium sordellii III. Agglutinability of Heat-Resistant Substrains of Clostridium sordellii  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Huang, C. T. (Kanazawa University, Kanazawa, Japan), Kenzo Tamai, and Shoki Nishida. Taxonomy of Clostridium bifermentans and Clostridium sordellii, III. Agglutinability of heat-resistant substrains of Clostridium sordellii. J. Bacteriol. 90:391–394. 1965.—By cross-agglutination tests with Clostridi...

Huang, C. T.; Tamai, Kenzo; Nishida, Shoki

324

Biochemical analysis of heat-resistant mouse tumor cell strains: a new member of the HSP70 family.  

Digital Repository Infrastructure Vision for European Research (DRIVER)

A series of heat-resistant mutants selected from a murine tumor cell line, RIF-1, display a markedly increased and stable resistance to heat shock. The mutant cell lines were analyzed for differences that may explain their increased resistance. Membrane lipid analysis showed no change in cholesterol...

Anderson, R L; Van Kersen, I; Kraft, P E; Hahn, G M

325

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

Heat-resistant agglutinin 1 (Hra1) is an accessory colonization factor of enteroaggregative Escherichia coli (EAEC) strain 042. Tia, a close homolog of Hra1, is an invasin and adhesin that has been described in enterotoxigenic E. coli. We devised a PCR-restriction fragment length polymorphism screen...

Mancini, Justin; Weckselblatt, Brooke; Chung, Yoonjie K.; Durante, Julia C.; Andelman, Steven; Glaubman, Jessica

326

Heat-resistant DNA tile arrays constructed by template-directed photoligation through 5-carboxyvinyl-2?-deoxyuridine  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Template-directed DNA photoligation has been applied to a method to construct heat-resistant two-dimensional (2D) DNA arrays that can work as scaffolds in bottom-up assembly of functional biomolecules and nano-electronic components. DNA double-crossover AB-staggered (DXAB) tiles were covalently conn...

Tagawa, Miho; Shohda, Koh-ichiroh; Fujimoto, Kenzo; Sugawara, Tadashi; Suyama, Akira

327

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

UK PubMed Central (United Kingdom)

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

Andrade T; Von Pinho EV; Von Pinho RG; Oliveira GE; Andrade V; Fernandes JS

2013-01-01

328

A Multiscale Approach to Deformation and Fracture of Heat-Resistant Steel Under Static and Cyclic Loading  

Digital Repository Infrastructure Vision for European Research (DRIVER)

Regularities of static and cyclic deformation, damage and fracture of heat-resistant steel 25Kh1M1F, based on the approaches of physical mesomechanics and 3D interferometry method, are presented in this paper. The applicability of these techniques for different hierarchy levels of deformation ...

Pavlo MARUSCHAK; Denys BARAN; Vladimir GLIHA

329

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 compo...

Odanovi?, Z.; Bla?i?, I.; Vra?ari?, D.; Grabulov, V.; Burzi?, M.; Katavi?, B.

330

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

International Nuclear Information System (INIS)

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

2010-04-25

331

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

Digital Repository Infrastructure Vision for European Research (DRIVER)

This study aimed to elucidate determinants of heat resistance in Escherichia coli by comparing the composition of membrane lipids, as well as gene expression, in heat-resistant E. coli AW1.7 and heat-sensitive E. coli GGG10 with or without heat shock. The survival of E. coli AW1.7 at late exponentia...

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

332

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

International Nuclear Information System (INIS)

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

1995-01-01

333

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

International Nuclear Information System (INIS)

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

1977-01-01

334

On the heat resistance of flake graphite cast iron containing low Ni  

Energy Technology Data Exchange (ETDEWEB)

The growth experiments were carried out in still air on cast irons to which Ni was added up to 3% to the flake graphite cast irons of FC 10 class to develop cheap heat resistant cast iron. The mechanical properties increased with the increase of Ni addition. Hardness increased similarly. Three cast irons grew by nearly 10% by 100 times repeated heating between room temperature to 950C. Similar growing tendency was shown with the heating times and further the growth rate decreased with the heating times. Furthermore, the growth of Ni containing cast irons were nearly equal throughout the heating but larger than that of conventional cast iron and the difference increased up to middle stage of heating. Ni containing cast irons had 50% higher mechanical properties than conventional cast iron at the 7% growth where cast iron has porous internal structure. In this connection, Ni containing cast iron indicated much lower growth rate after the middle stage of heating. (10 figs, 2 tabs, 20 refs)

Soma, Makoto; Hasebe, Makoto

1988-05-30

335

Heat resisting T92/P92 steel, its welding and properties of welded joints  

International Nuclear Information System (INIS)

[en] Basic characteristics of the T/P92 steel are given and its creep strength in comparison with other heat resisting steel grades. The influence of welding thermal cycles on the properties of simulated heat affected zones has been examined and it was found, that in a wide range of t8/5 cooling times martensite is present with a hardness higher than 400 HV and a low notch toughness. But joints made of T92 tubes (?51,0 x 7.0 mm) and pipes P92 (? 219 x 20 mm) have been TIG welded with the P92-IG wire by using FOX 92 stick electrodes in the horizontal (PC) and vertical up (PF and H-L045) positions and post-weld heat treated. Examination results of the test joints have revealed their good mechanical and plastic properties, a hardness not exceeding 285 HV, a high Charpy V notch toughness of the parent material and HAZ. The notch toughness of welds was lower, but it satisfies the requirements of the technical inspection societies. (author)

2002-01-01

336

Basidioascus and Geminibasidium: a new lineage of heat-resistant and xerotolerant basidiomycetes.  

Science.gov (United States)

Using a heat-treatment method, two genera of heat-resistant and xerotolerant basidiomycetes were isolated from soil samples. These two genera, Basidioascus and Geminibasidium gen. nov., are morphologically similar and phylogenetically related. The genus Basidioascus originally was described as an ascomycete, but the structures originally interpreted as single-spored asci appear to represent basidiospores. Morphologically both genera are characterized by the lack of a fruiting body, conspicuously granular and deciduous basidia with a unique basal lateral projection and apparently double-walled basidiospores. The basidia, rather than the basidiospores, are forcibly discharged in Basidioascus species but not in Geminibasidium species. In Geminibasidium species a putative basidium arises from a primary cell. These are novel forms of basidia ontogenesis previously unseen in basidiomycetes. The rDNA (SSU + 5.8S + LSU) Bayesian phylogenetic analysis suggests that these fungi are distantly related to Wallemia, another xerotolerant basidiomycete genus commonly found in indoor air dust, dried foods and natural hypersaline environments. Given the physiological similarity and phylogenetic relationships, Basidioascus and Geminibasidium are classified in a new order, Geminibasidiales, and are taxonomically assigned to the class Wallemiomycetes. Based on morphological observations and molecular phylogeny of the internal transcribed spacer (ITS), two species of Basidioascus (B. undulatus, B. magus sp. nov.) and two species of Geminibasidium (G. donsium sp. nov., G. hirsutum sp. nov.) are described. A key to these species is provided using micromorphological and cultural characters. PMID:23709525

Nguyen, Hai D T; Nickerson, Nancy L; Seifert, Keith A

2013-05-25

337

Basidioascus and Geminibasidium: a new lineage of heat-resistant and xerotolerant basidiomycetes.  

UK PubMed Central (United Kingdom)

Using a heat-treatment method, two genera of heat-resistant and xerotolerant basidiomycetes were isolated from soil samples. These two genera, Basidioascus and Geminibasidium gen. nov., are morphologically similar and phylogenetically related. The genus Basidioascus originally was described as an ascomycete, but the structures originally interpreted as single-spored asci appear to represent basidiospores. Morphologically both genera are characterized by the lack of a fruiting body, conspicuously granular and deciduous basidia with a unique basal lateral projection and apparently double-walled basidiospores. The basidia, rather than the basidiospores, are forcibly discharged in Basidioascus species but not in Geminibasidium species. In Geminibasidium species a putative basidium arises from a primary cell. These are novel forms of basidia ontogenesis previously unseen in basidiomycetes. The rDNA (SSU + 5.8S + LSU) Bayesian phylogenetic analysis suggests that these fungi are distantly related to Wallemia, another xerotolerant basidiomycete genus commonly found in indoor air dust, dried foods and natural hypersaline environments. Given the physiological similarity and phylogenetic relationships, Basidioascus and Geminibasidium are classified in a new order, Geminibasidiales, and are taxonomically assigned to the class Wallemiomycetes. Based on morphological observations and molecular phylogeny of the internal transcribed spacer (ITS), two species of Basidioascus (B. undulatus, B. magus sp. nov.) and two species of Geminibasidium (G. donsium sp. nov., G. hirsutum sp. nov.) are described. A key to these species is provided using micromorphological and cultural characters.

Nguyen HD; Nickerson NL; Seifert KA

2013-09-01

338

Laves phase evolution in a modified P911 heat resistant steel during creep at 923 K  

International Nuclear Information System (INIS)

Highlights: ? Laves phase particles appear mainly on high-angle boundaries. ? Volume fraction of Laves phase increases to saturation during creep for about 3000 h. ? Sizes of Laves phase particles are expressed by power law functions of creep time. ? Grow exponents of 6.7 and 8.3 are obtained for particles located on HABs and LABs. - Abstract: The evolution of Fe2(W, Mo) Laves phase in a 3%Co modified P911 heat resistant steel was examined during creep tests at 923 K. The tempered martensite lath structure evolved after heat treatment was characterized by dispersion of MX carbonitrides and M23C6 carbides. Appearance of Laves phase particles was recorded after a creep strain of 1%. The mean size of Laves phase particles increased from 190 to 265 nm with increasing strain to 18%. The Laves phase particles were spaced on various boundaries including low-angle boundaries (LABs) of laths/subgrains, but most of these particles (about 90%) were located on high-angle boundaries (HABs) at all strains studied. The size of Laves phase particles located on HABs was larger and their coarsening kinetics was faster than those precipitated on LABs. It is assumed that the evolution of Laves phase during creep is controlled by the grain boundary diffusion of tungsten and molybdenum.

2012-01-15

339

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

340

Preparation of heat-resistance waterborne coatings containing synthetic hectorite clay  

Energy Technology Data Exchange (ETDEWEB)

Three different composition of waterborne coatings (WBC-0, WBC-1, WBC-2) were prepared by the compounding of synthesized hectorite clay (SHC) from the hydrothermal reaction with acryl latex and coating additives. The pH, solution viscosity and solid content of WBCs were investigated, and the rheological properties with the shear rate measured by the rheometer. Also, the thermal stability and the transmittance of the films casted by WBCs were investigated by thermogravimetry analysis and UV-VIS spectrophotometer, respectively. WBC-2 containing 8 phr SHC showed the phase transition of sol and gel with the shear rate, that is, the thixotropic property, and the storage stability of WBC-2 increased by means of its phenomenon. The initial decomposition temperature and the transmittance of films casted by WBC-1 and WBC-2 increased in range of 99.6 {approx}110.2{sup 0} deg. C and 20.9 {approx} 21.7% than the commercial WBC, respectively. As a consequence, WBC containing SHC showed increasing effect both the heat-resistance and the solution viscosity by the water swellable clay. (author). 14 refs., 4 tabs., 5 figs.

Lee, S.K. [Kyungil University, Kyungsan (Korea); Lee, B.K. [Kyungpook National University, Taegu (Korea)

2001-02-01

 
 
 
 
341

Chemical solution growth of CeO2 buffer and YBCO layers on IBAD-YSZ/Hastelloy templates  

International Nuclear Information System (INIS)

Low-cost and commercially viable processes to fabricate coated conductors are necessary for application in electric-power technologies. We demonstrate the chemical solution growth of CeO2 buffer and YBCO layers on IBAD-YSZ/Hastelloy templates. Very good biaxially textured CeO2 buffer layers can be formed by the chemical solution method using inorganic cerium nitrate precursors. Through control of the solution molarity, very uniform, smooth, and dense CeO2 buffer layers can be obtained. Subsequently, the YBCO films were deposited by metallorganic deposition using the trifluoroacetic (TFA-MOD) method. High-critical-current-density (Jc) YBCO films were obtained, with the transport current density of about 1.2 MA cm-2 (77 K, 0 T). The onset transition temperature is as high as 94.5 K, and the transition width is about 1.3 K. Hence, the mature IBAD technique, combined with the low-cost solution method, can provide a very promising robust process for fabrication of low-cost YBCO coated conductor on a large scale.

2005-01-01

342

Chemical solution growth of CeO2 buffer and YBCO layers on IBAD-YSZ/Hastelloy templates  

Science.gov (United States)

Low-cost and commercially viable processes to fabricate coated conductors are necessary for application in electric-power technologies. We demonstrate the chemical solution growth of CeO2 buffer and YBCO layers on IBAD-YSZ/Hastelloy templates. Very good biaxially textured CeO2 buffer layers can be formed by the chemical solution method using inorganic cerium nitrate precursors. Through control of the solution molarity, very uniform, smooth, and dense CeO2 buffer layers can be obtained. Subsequently, the YBCO films were deposited by metallorganic deposition using the trifluoroacetic (TFA-MOD) method. High-critical-current-density (Jc) YBCO films were obtained, with the transport current density of about 1.2 MA cm-2 (77 K, 0 T). The onset transition temperature is as high as 94.5 K, and the transition width is about 1.3 K. Hence, the mature IBAD technique, combined with the low-cost solution method, can provide a very promising robust process for fabrication of low-cost YBCO coated conductor on a large scale.

Wang, S. S.; Han, Z.; Schmidt, W.; Neumuller, H. W.; Du, P.; Wang, L.; Chen, S.

2005-11-01

343

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

UK PubMed Central (United Kingdom)

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

Guizelini BP; Vandenberghe LP; Sella SR; Soccol CR

2012-12-01

344

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

Science.gov (United States)

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

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

2012-08-08

345

High Temperature Mechanical Properties of HK40-type Heat-resistant Cast Austenitic Stainless Steels  

Science.gov (United States)

This work characterized HK40-type, cast austenitic stainless steel, as the W content was varied from 0 to 3.6 wt.%. Analysis of microstructure using optical and scanning electron microscopies showed that the alloys contained relatively large amount of Cr-carbide, Nb-compound, and MnS at the austenite grain boundary. The addition of W promoted the formation of Cr-carbide and affected the high-temperature mechanical properties. According to tension tests carried out at room temperature, 400, 600, and 800 °C, the alloys became significantly stronger and brittle as W content increased. The low-cycle fatigue tests showed that fatigue resistance was also increased with W addition, but an excessive amount of W decreased the fatigue resistance. The HK40-type alloys with 2.0 wt.% W exhibited best high-temperature mechanical performances.

Kim, Yoon-Jun; Lee, Dong-Geun; Jeong, Hyeon Kyeong; Lee, Yong-Tai; Jang, Ho

2010-07-01

346

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

DEFF Research Database (Denmark)

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

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

2012-01-01

347

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

UK PubMed Central (United Kingdom)

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

de Jong AE; van Asselt ED; Zwietering MH; Nauta MJ; de Jonge R

2012-01-01

348

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; A. R. Soomro; A. W. Soomro; Rehana Anjum; Saira Bano Babar

2001-01-01

349

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

Energy Technology Data Exchange (ETDEWEB)

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{mu}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.).

Hamada, Kazushi; Tokuno, Kazushige

1994-09-27

350

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

International Nuclear Information System (INIS)

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

1999-01-01

351

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; J.D. Brooks

2005-01-01

352

Molecular design of high heat-resistant low-molecular amorphous materials; Kotainetsusei teibunshi amorphous zairyo no bunshi sekkei  

Energy Technology Data Exchange (ETDEWEB)

At present, high heat-resistant low-molecular amorphous materials are taken notice of as an organic electroluminescent element and other functional coloring compounds. The present paper explains the correlativity between the thermal characteristics and molecular structure of amorphous materials, and design to synthesize the high heat-resistivity amorphous coloring molecules. The transition temperature (Ttr) of glass is defined as the temperature at which the supercooled liquid viscosity is 10{sup 13} poises. Relation was studied between the Ttr and melting entropy, decreasing exponentially, of the non-associative aromatic and aliphatic compounds, mono hydrogen bonding aromatic and aliphatic compounds, and poly hydrogen bonding molecule. Their relation was also studied between the crystal growth velocity and crystal max. temperature (Tc max), and between the max. crystallizing velocity (MCV) and melting enthalpy. From the study, derived and proposed was a general formula in which the logarithm of MCV was equal to the sum of transition enthalpy and melting enthalpy. The structure of high heat-resistivity amorphous molecule was studied by adding a HSE theory to the proposed formula. An experimental product was synthesized which gave a high transition temperature at the same level as the engineering plastics. It is designable to control the Ttr, Tc max, MCV and other physical values. 7 refs., 4 figs.

Naito, K. [Toshiba Corp., Tokyo (Japan)

1994-09-01

353

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

International Nuclear Information System (INIS)

[en] 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

354

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

355

Sporulation environment of emetic toxin-producing Bacillus cereus strains determines spore size, heat resistance and germination capacity.  

UK PubMed Central (United Kingdom)

AIM: Heat resistance, germination and outgrowth capacity of Bacillus cereus spores in processed foods are major factors in causing the emetic type of gastrointestinal disease. In this study, we aim to identify the impact of different sporulation conditions on spore properties of emetic toxin-producing B. cereus strains. METHODS AND RESULTS: Spore properties of eight different emetic toxin-producing strains were tested, with spores produced in five different sporulation conditions: aerated liquid cultures, air-liquid biofilms, 1.5% agar plates, 0.75% agar plates and swarming colonies. Model food studies revealed spores from emetic toxin-producing strains to germinate efficiently on meat broth- and milk-based agar plates, whereas germination on rice-based agar plates was far less efficient. Notably, spores of all strains germinated efficiently when 0.1% meat broth was added to the rice plates. Analysis of spores derived from different environments revealed large diversity and showed biofilm spores for the strains tested to be the largest in size, the most heat resistant and with the lowest germination capacity. CONCLUSIONS: Sporulation in complex conditions such as biofilms and surface swarming colonies increases heat resistance and dormancy of spores. SIGNIFICANCE AND IMPACT OF THE STUDY: The results obtained imply the importance of sporulation conditions on spore properties of emetic toxin-producing B. cereus strains, as occur for instance in food processing.

van der Voort M; Abee T

2013-04-01

356

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.; Kolupaev Yu.Ye.; Vayner A.O.

2012-01-01

357

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1997-07-01

358

Magnesium Cermets and Magnesium-Beryllium Alloys  

International Nuclear Information System (INIS)

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

1963-01-01

359

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

360

Relation between fracture mode and carbide of Hastelloy XR creep-tested in helium M23C6/M6C environment; Helium chu de creep shiken wo okonatta Hastelloy XR no hadan mode to M23C6/M6C tankabutsu no kankei  

Energy Technology Data Exchange (ETDEWEB)

The Hastelloy XR high-temperature creep test is conducted for the investigation of relationship between the fracture mode and boundary layer carbide. The Hastelloy X available in the market is developed into a Hastelloy XR specimen by adjusting the minor elements for use in a helium-cooled atomic reactor. Creep tests are conducted at 800, 900, and 1000{degree}C, with the longest test lasting for 48,588 hours at 900{degree}C, in a helium atmosphere containing traces of H2, H2O, CO, CO2, CH4, etc., approximating an environment in a high-temperature gas-cooled reactor. It is found that all fractures take place at grain boundaries. As for the fracture mode, wedge types are formed at 800 and 900{degree}C at grain boundary triple points on the short-time side and, on the long-time side, cavity types are formed mainly at interfaces with carbide. At 1000{degree}C, some are partially ruptured. Carbide from the 1000{degree}C test is divided into the M23C6 type whose main component is Cr and the M6C type whose main component is Mo. 11 refs., 6 figs., 3 tabs.

Ogawa, Y. [Tohoku University, Sendai (Japan). Institute for Materials Research; Kurata, Y.; Suzuki, T. [Japan Atomic Energy Research Institute, Tokyo (Japan); Monma, Y.; Yoshizu, H. [National Research Institute for Metals, Tokyo (Japan); Kondo, T. [Tohoku University, Sendai (Japan). Faculty of Engineering

1997-05-01

 
 
 
 
361

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

Energy Technology Data Exchange (ETDEWEB)

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

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

1984-02-02

362

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

Directory of Open Access Journals (Sweden)

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

C. Kolmasiak

2012-01-01

363

Recent research and development trends of heat resistant steel tubes and pipes for high temperature application. Koon sochi yo tainetsu kokan no saikin no kaihatsu doko  

Energy Technology Data Exchange (ETDEWEB)

As the energy matters have recently been changing, the environments of usage of heat resistant steel tubes and pipes have become stricter and the performance required for materials thereof has become increasingly severer. Since heat resistant steel tubes and pipes are all used in the high temperature and corrosive environments, not only corrosion resistance and high temperature strength is required, but also workability, weldability and economy is required as the important performance. Accordingly, it is not easy to develop any heat resistant material fulfilling all the above requirements. In this article, rough explanations are made on the development trends and the issues in the future on the materials for heat resistant tubes and pipes for boilers for thermal generation, and the recent development trends and the issues in the future on heat resistant steel tubes and pipes for fast breeder reactor, material for heat exchanger for high temperature gas furnace, and heat resistant pipes for cracking furnace pipes. In 1990 {prime} s, the global environmental problems, energy saving and diversification of energy sources will become important issues as the general circumstances, hence development and practical application of materials of high performance and high function is desired more. 47 refs., 7 figs., 3 tabs.

Sawaragi, Y. (Sumitomo Metal Industries Ltd., Osaka (Japan))

1991-05-25

364

Ocorrência de fungos filamentosos termo-resistentes em polpa de tomate envasada assepticamente Occurrence of heat resistant molds in tomato pulp packed aseptically  

Directory of Open Access Journals (Sweden)

Full Text Available Este trabalho teve como objetivo principal determinar a ocorrência de fungos filamentosos termo-resistentes durante o processamento asséptico de polpa de tomate (8° BRIX). Durante o período de safra de tomate foram feitas amostragens em 9 lotes (3 no início, 3 no pico e 3 em fim de safra) e no período de entresafra em 5 lotes. Foi feita a enumeração de fungos termo-resistentes nas amostras coletadas durante as diferentes etapas do processo asséptico de cada lote. Foram obtidas contagens médias relativamente baixas, variando entre This work aimed at determining the occurrence of heat resistant molds during the aseptic processing of tomato pulp (8° BRIX). During tomato harvest, 9 lots were sampled (3 at the beginning, 3 at the apex and 3 at the end of harvest) and other 5 lots were sampled between harvest. For each lot, the enumeration of heat resistant molds was carried out in samples collected during the aseptic process. The mean count of heat resistant molds was relatively low, ranging from <1 to 8CFU/100mL of sample. The higher counts were observed in the raw material and the pre-wash and transportation water. Fifty strains of heat resistant molds detected in the enumeration procedure were isolated, codified and stocked. One-month-old spores of each isolate were submitted to different heat shocks to select the most heat resistant mold. The most heat resistant isolated strain (survived 100° C/25 minutes) was identified as Neosartorya fischeri.

Flávio BAGLIONI; Homero Ferracini GUMERATO; Pilar Rodriguez MASSAGUER

1999-01-01

365

High temperature ductility of austenitic alloys exposed to thermal neutrons  

International Nuclear Information System (INIS)

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

1982-01-01

366

Eutectic solidification of binary alloys  

Energy Technology Data Exchange (ETDEWEB)

The eutectic is a common multiphase metallurgical constituent. Yet all previous theories of eutectic reaction shared one shortcoming - they lacked an adequate understanding of the eutectic grain structure. Focusing on metallography, Dnepropetrovsk school of thought founded by K.P. Bunin has devised a new concept of eutectic structure formation relying on findings in solidification of Fe-, Al-, Ti-, Cu-, Zn-, Pb- and Sn-base eutectic alloys. Eutectic solidification of binary alloys has been found to occur by joint cooperative growth of finely branched dendrites of the eutectic constituents. A eutectic grain is a two-phase bicrystal whose morphology is determined by the crystallochemical nature of the eutectic's base constituent. Based on studies into genesis and morphology of eutectics, new families of eutectic-type alloys were developed, such as deformable white irons, Boralloys (high-boron wear resistant iron alloys), Ticads (heat resistant titanium-silicon alloys), and Gasars (porous metallic materials for a wide variety of applications). (author)

Makrinovich, M

2000-07-01

367

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

368

The fabrication of heat resistant composite materials by the injection of PSP resin into a woven reinforcement material  

Energy Technology Data Exchange (ETDEWEB)

The injection molding of fiber glass reinforced thermostable PSP composites, which have been found to exhibit good mechanical properties at high temperatures as well as excellent fire and moisture resistance, is investigated. Specimens were fabricated by the injection of molten resin into a preheated mold containing dry fiberglass reinforcement, followed by curing under pressure. The effects of resin properties, glass fiber proportion and oiling and curing cycle conditions on laminate properties are indicated, by process optimization, possibly approaching the properties of composites fabricated by traditional techniques. The technique has been applied to the successful fabrication of a heat-resistant glass-reinforced plastic missile radome.

Bloch, B.

1980-01-01

369

Influence of scaling on the fatigue performance of heat resistant steels. Einfluss der Zunderung auf das Zeitstandverhalten hitzebestaendiger Staehle  

Energy Technology Data Exchange (ETDEWEB)

In fatigue tests of heat resistant steels, there occurs a reduction of the time-dependent strength values at specimens of smaller test dimension and in consequence of test interruptions, which can only be partly explained by a cross sectional loss in consequence of scaling. Even the formation of a peripheral layer representing a zone of reduced carbide density and of reduced solidness does not represent a sufficient explanation. In addition, there are probably involved fatigue cracks, concentrated in the peripheral zone and initiated by oxidation. Even at the extremely low stressed specimens, an influence of bending stress cannot be excluded in case of interrupted test procedure. (orig./MM)

Kloos, K.H.; Granacher, J.; Holdinghausen, A.

1992-01-01

370

Method for studying the cyclic characteristics of heat-resistant materials under dual-frequency asymmetric loading at high temperatures  

Energy Technology Data Exchange (ETDEWEB)

A method and equipment for the high temperature testing of heat-resistant materials are described which employ axisymmetric loading at constant stress amplitude in the low-cycle and high-cycle regions. Examples of low-cycle and high-cycle dual-frequency test schedules implemented on the test stand described here are presented. The general design and the operation of the test stand are discussed, and a circuit diagram of the electronic system for the stabilization of low-frequency loading is shown. 7 references.

Sinaiskii, B.N.; Butseroga, V.P.; Gorodetskii, V.A.; Skonechnykh, G.K.

1987-07-01

371

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.

2008-01-01

372

Effect of pH of the recovery medium on the apparent heat resistance of three strains of Bacillus cereus.  

Science.gov (United States)

The influence of pH of the recovery medium, in the range 7.6-5.4, on the apparent heat resistance of three strains of Bacillus cereus (ATCC 4342, 7004 and 9818) has been investigated. The highest counts of heat-injured spores were obtained at pH near neutral, decreasing markedly as pH was reduced, especially with longer heating times. When the media were acidified, the apparent D-values tended to decrease, although some exceptions related to the strain and the nature of the medium were observed. z-Values determined were not affected by the pH of the medium. PMID:8880321

González, I; López, M; Mazas, M; Bernardo, A; Martín, R

1996-08-01

373

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

2007-08-21

374

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

International Nuclear Information System (INIS)

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

1993-01-01

375

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

International Nuclear Information System (INIS)

[en] The temperature dependent current density - potential behavior of Hastelloy C 4 in Q-brine is determined for T=250C and T=900C. The material gets passivated instantaneously. The stability of the protecting passivated layer is greatly reduced at T >= 550C to 600C. Some of the specimens differ greatly from each other in their behavior which is attributed to inhomogeneities in the structure and composition of the materials. The results obtained from the electrochemical corrosion studies make evident a clear effectiveness of various impurities and radiolytic products potentially occurring in brines produced in an accident. These impurities and radiolytic products cause a destruction of this material through local corrosion depending on their concentration and time. (orig./PW)[de] Das temperaturabhaengige Stromdichte-Potential-Verhalten von Hastelloy C 4 in Q-Loesung wird fuer T=250C und T=900C bestimmt. Der Werkstoff passiviert sich spontan. Die Stabilitaet der schuetzenden Passivschicht verringert sich stark fuer T >= 550C - 600C. Das Verhalten verschiedener Proben variiert teilweise stark voneinander und wird auf strukturelle und zusammensetzungsbedingte Inhomogenitaeten im Material zurueckgefuehrt. Die vorliegenden Ergebnisse der elektrochemischen Korrosionsuntersuchungen lassen eine deutliche Wirksamkeit verschiedener, in stoerfallbedingten Salzloesungen moeglichen Verunreinigungen und Radiolyseprodukten erkennen, die in Abhaengigkeit von Konzentration und Zeit zu einer Zerstoerung dieses Werkstoffes durch lokale Korrosion fuehren. (orig./PW)

1986-01-01

376

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

377

Effect of NaCl on Heat Resistance, Antibiotic Susceptibility, and Caco-2 Cell Invasion of Salmonella.  

UK PubMed Central (United Kingdom)

This study evaluated the effects of NaCl on heat resistance, antibiotic susceptibility, and Caco-2 cell invasion of Salmonella. Salmonella typhimurium NCCP10812 and Salmonella enteritidis NCCP12243 were exposed to 0, 2, and 4% NaCl and to sequential increase of NaCl concentrations from 0 to 4% NaCl for 24?h at 35°C. The strains were then investigated for heat resistance (60°C), antibiotic susceptibility to eight antibiotics, and Caco-2 cell invasion efficiency. S. typhimurium NCCP10812 showed increased thermal resistance (P < 0.05) after exposure to single NaCl concentrations. A sequential increase of NaCl concentration decreased (P < 0.05) the antibiotic sensitivities of S. typhimurium NCCP10812 to chloramphenicol, gentamicin, and oxytetracycline. NaCl exposure also increased (P < 0.05) Caco-2 cell invasion efficiency of S. enteritidis NCCP12243. These results indicate that NaCl in food may cause increased thermal resistance, cell invasion efficiency, and antibiotic resistance of Salmonella.

Yoon H; Park BY; Oh MH; Choi KH; Yoon Y

2013-01-01

378

Increased heat resistance in mycelia from wood fungi prevalent in forests characterized by fire: a possible adaptation to forest fire.  

UK PubMed Central (United Kingdom)

Forest fires have been the major stand-replacing/modifying disturbance in boreal forests. To adapt to fire disturbance, different strategies have evolved. This study focuses on wood fungi, and a specific adaptation to forest fire: increased heat resistance in their mycelia. Fifteen species of wood fungi were selected and a priori sorted in two groups according to their prevalence in fire-affected environments. The fungi were cultivated on fresh wood and exposed to 100, 140, 180, 220 °C for 5, 10, 15, 20 and 25 min. under laboratory conditions. A clear difference was found among the two groups. Species prevalent in fire-affected habitats had a much higher survival rate over all combinations of time and temperature compared to species associated with other environments. Thus, the results indicate that fire adaptation in terms of increased heat resistance in mycelia occurs in some species of wood fungi. Such adaptation will influence the ecology and population dynamics of wood fungi, as well as having implications for best practices during restoration fires.

Carlsson F; Edman M; Holm S; Eriksson AM; Jonsson BG

2012-10-01

379

Fracture toughness of a X alloy under static load  

International Nuclear Information System (INIS)

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

1979-08-17

380

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

International Nuclear Information System (INIS)

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

1975-01-01

 
 
 
 
381

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

International Nuclear Information System (INIS)

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

2000-01-01

382

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

383

Tellurium corrosion of nickel-based alloys in fuel salts  

International Nuclear Information System (INIS)

For high-temperature molten salt reactors corrosion of the metallic container alloy in primary circuit is the concern. This paper summarizes results of an experimental investigation conducted recently to understand the mechanism and to develop a means of controlling tellurium embrittlement in the nickel-based alloys. The addition of a chromium telluride to salt can be used to provide small partial pressures of tellurium simulating a reactor environment where tellurium appears as a fission product. Tellurium corrosion of Ni-based alloys in stressed and unloaded conditions studies was tested in molten LiF-NaF-BeF2 and LiF-BeF2-ThF4-UF4 (mole%) salt mixtures at temperatures up to 700degC with measurement of the redox potential. Following Hastelloy N-type modified alloys: HN80M-VI with 1.5% Nb, HN80MTY with 1% Al and MONICR with about 2% Fe were used for the study in the LiF-NaF-BeF2 corrosion facilities. Materials investigated in LiF-BeF2-ThF4-UF4 fuel salt include, in addition to mentioned above, high temperature HN80MTB (77Ni-10Mo-6W-7Cr) and EM-721 (65Ni-28W-7Cr) alloys. (author)

2011-01-01

384

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

Energy Technology Data Exchange (ETDEWEB)

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

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

2008-05-15

385

PREPARATION METHOD OF HEAT RESISTANT EPOXY RESIN FROM SPECIFIC KIND OF BIS(HYDROXYPHENYL)FLUORENE AND EPICHLOHYDRIN  

UK PubMed Central (United Kingdom)

PURPOSE: Provided is a method for preparing a heat resistant epoxy resin which is excellent in transparency and is suitable for a display material, an optical device and an optical modulation device. CONSTITUTION: The method comprises the step of reacting a bis(hydroxyphenyl)fluorene represented by the formula 1 and epichlohydrin to prepare an epoxy resin, wherein the bis(hydroxyphenyl)fluorene has a yellow index of 6 or less at an optical path of 10 mm in a solution of 4 g of bis(hydroxyphenyl)fluorene dissolved in 100 ml of methylethylketone and contains 100 ppm or less of fluorenone, and the epoxy resin has a color of APHA120 or less. In the formula 1, Rs are identical or different each other and are an alkyl group and m and n are an integer of 0-3.

AKIMARU YUKUO; FUJISHIRO KOICHI; MANAGO HIROTOSHI; MATSUGAKI KAZUNORI; MITANI MOTOZUMI

386

Effects of Ni and TiN Coatings on the Alumina/Heat-Resistant Steel Interface Properties  

Science.gov (United States)

Ni and TiN coatings on alumina particles were achieved using a chemical vapor deposition (CVD) method. The coated alumina was then used as raw materials to prepare alumina/heat-resistant steel (HRS) composites. The effects of Ni/TiN coatings on the alumina/HRS interface strength and oxidation resistance at elevated temperature were investigated. It is found that the both coatings can improve the alumina/HRS interface bonding strength and Ni coating has a more significant effect. For the composite made from Ni-coated alumina and HRS, the interface exhibited a better oxidation resistance due to the dissolution of Ni coating into the HRS matrix. However, the composite of TiN-coated alumina/HRS has a poor oxidation resistance behavior because TiN still existed on the alumina/HRS interface.

Wang, Enze; Yi, Yong; Xie, Hua; Fan, Yongge

2006-01-01

387

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

Science.gov (United States)

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

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

2012-11-01

388

A Multiscale Approach to Deformation and Fracture of Heat-Resistant Steel Under Static and Cyclic Loading  

Directory of Open Access Journals (Sweden)

Full Text Available Regularities of static and cyclic deformation, damage and fracture of heat-resistant steel 25Kh1M1F, based on the approaches of physical mesomechanics and 3D interferometry method, are presented in this paper. The applicability of these techniques for different hierarchy levels of deformation was studied. The investigation of scanning microscope photos was conducted for several dissipative structures, fragmentation of the material, localisation of macrodeformation and subsequent failure on macro- and mesolevel. It is shown that the used modern techniques of experimental analysis are very efficient in understanding deformation and damage evolution in materials.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3821

Pavlo MARUSCHAK; Denys BARAN; Vladimir GLIHA

2013-01-01

389

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

International Nuclear Information System (INIS)

Microstructural states of metallic materials can be expressed by system free energy, and the estimation of the system free energy is useful for damage analysis of the materials. In this study, change with creep time in the system free energy of the FG-HAZ in 9Cr heat resistant ferritic steels is estimated on the basis of a series of experiments such as chemical analysis by using extracted residues, X-ray diffraction, and scanning transmission observations. The change in the system free energy is expressed quantitatively by rate constants depending on applied stress. It is observed that the steel ruptures when the applied stress exceeds the allowable stress. The relationship between allowable stress and system free energy makes it possible to predict the rupture time in the long term. (author)

2011-10-21

390

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

International Nuclear Information System (INIS)

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

2013-01-01

391

Alloy separator for solid oxide electrolyte fuel cell and fabrication method. Kotai denkaishitsugata nenryo denchiyo gokin separator oyobi sono seizo  

Energy Technology Data Exchange (ETDEWEB)

Heat resisting alloys have been put to practical use in lieu of ceramics to be used for the separator of the solid oxide electrolyte fuel cell. Oxide film mainly made of alloy element is formed on the air electrode side together with oxide mainly made of base metal because the heat resisting alloy separator is used at high temperatures near 1000[degree]C. In addition, oxide mainly composed of alloy element is formed on the fuel electrode side. As a result, the electric conductivity is decreased to impair the electrical connecting function between unit cells. This invention relates to provision of a nickel plated layer on the fuel electrode surface side of the separator structured with heat resisting alloy and provision of an LaCrO3 system plated layer on the air electrode surface side by wet plating processing. Such wet plating of specific metal or metal oxide on the separator prevents the oxidation of the separator and the decrease in the electrical connecting function. 3 figs

Umemura, F.

1993-02-12

392

Laser cutter for cutting animal claw, has claw cutter aperture made of heat resistant/opaque material for supporting animal claw to perform laser cutting of animal claw  

UK PubMed Central (United Kingdom)

The laser cutter has a claw cutter aperture (700) made of heat resistant/opaque material for supporting animal claw. Laser cutting of the animal claw is performed vertically/horizontally by supplying voltage to the laser cutter by the voltage sources (400,500). A rotary module (100) is arranged to move the laser cutter.

KUCH MARTIN

393

[Induction of heat resistance in wheat coleoptiles by salicylic and succinic acids: connection of the effect with the generation and neutralization of active oxygen forms].  

UK PubMed Central (United Kingdom)

The influence of salicylic (SaA) and succinic (SuA) acids on the generation of active oxygen forms (AOFs) and the heat resistance of wheat (Triticum aestivum L.) coleoptiles has been studied. The treatment of coleoptiles with 10 microM SaA or SuA results in the accumulation of hydrogen peroxide and enhanced formation of a superoxide anion radical. This effect is partially suppressed by both alpha-naphthol (the NADPH oxidase inhibitor) and salicylhydroxamic acid (peroxidase inhibitor). SaA and SuA cause an increase in the activity of antioxidant enzymes, such as superoxide dismutase, catalase, and soluble peroxidase, and improve the heat resistance ofcoleoptiles. Antioxidant ionol and compounds, which inhibit the NADPH oxidase and peroxidase, significantly reduce the positive influence of SaA and SuA on the heat resistance of wheat coleoptiles. AOFs are considered to be intermediates for heat resistance induction in coleoptiles, treated with SaA and SuA; enhanced AOF generation can be caused by an increased activity of the NADPH oxidase and peroxidase.

Kolupaev IuE; Iastreb TO; Shvidenko NV; Karpets IuV

2012-09-01

394

Amplification and altered expression of the hsc70/U 14 snoRNA gene in a heat resistant Chinese hamster cell line  

Digital Repository Infrastructure Vision for European Research (DRIVER)

We have recently demonstrated that the heat resistant phenotype of the HR-1 variant isolated from HA-1 Chinese hamster fibroblasts after a series of heat shocks is associated with the increased expression of Hsc70, the constitutive form of Hsp70 (Laszlo and Li 1985). Here, we report the cloning and ...

Chen, Ming-Shun; Featherstone, Terrence; Laszlo, Andrei

395

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

Science.gov (United States)

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

Takahashi, A.; Ohnishi, T.

2009-04-01

396

High temperature corrosion of iron-base and nickel-base alloys for hydrogen production apparatus by thermochemical method in H{sub 2}O+SO{sub 3} atmosphere  

Energy Technology Data Exchange (ETDEWEB)

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

Kurata, Yuji; Suzuki, Tomio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Shimizu, Saburo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

2000-03-01

397

A 31 mW, 280 fs passively mode-locked fiber soliton laser using a high heat-resistant SWNT/P3HT saturable absorber coated with siloxane.  

UK PubMed Central (United Kingdom)

We report a substantial increase in the heat resistance in a connector-type single-wall carbon nanotube (SWNT) saturable absorber by sealing SWNT/P3HT composite with siloxane. By applying the saturable absorber to a passively mode-locked Er fiber laser, we successfully demonstrated 280 fs, 31 mW pulse generation with a fivefold improvement in heat resistance.

Ono T; Hori Y; Yoshida M; Hirooka T; Nakazawa M; Mata J; Tsukamoto J

2012-10-01

398

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

Directory of Open Access Journals (Sweden)

Full Text Available Metallurgical evaluation was performed on a fractured column tube of the reformer furnace in an ammonia plant. The tubes were manufactured from centrifugally cast heat resistant steel HK 40. Optical and scanning electron microscope (SEM) were used for microstructural and fracture analysis. For composition determination of the microconstituents energy dispersive X ray spectroscopy (EDS) was used. To evaluate mechanical properties, hardness and microhardness measurements were performed. Investigations based on the microstructural features with the idea to indicate suitability of weld repair of the column were performed in this study. It was observed that the crack initiation, caused by oxidation/corrosion and thermal stresses induced by temperature gradient, appeared in the inner side of the tube wall and propagation occurred along grain boundaries. The results clearly showed the presence of an irregular microstructure which contributed to crack propagation through the tube wall. An occurrence of precipitated needle-shaped carbides/carbonitrides and brittle ? phase was also identified in the microstructure. Results of the microstructural and fracture analysis clearly indicate that reformer furnace columns made of heat resistant steel HK 40 were unsuitable for weld repair.La evaluación metalúrgica se realizó en un tubo de columna con fracturas, que es parte del horno reformador en una planta de amoníaco. Estos tubos son fundidos centrífugamente y fabricados en acero resistente al calor, de tipo HK- 40. Para el análisis microestructural de la fractura se ha utilizado microscopía óptica y electrónica de barrido (SEM). La composición de los micro-constituyentes se determinó por espectrometría de rayos X de energía dispersiva (EDS). Las propiedades mecánicas se evaluaron mediante mediciones de microdureza Vickers. Las investigaciones en este estudio se han llevado a cabo con el fin de demostrar la idoneidad de reparación por soldadura de columnas en base a sus características micro-estructurales. Se ha observado que el inicio de la rotura, causada por el efecto de la oxidación/corrosión y el choque térmico ocasionado por el gradiente de temperatura, aparece en la pared interna del tubo y se propaga a lo largo de los bordes de grano. Los resultados demuestran la presencia de una microestructura irregular que contribuyó a la propagación de la rotura a lo largo de la pared del tubo. En la microestructura también se ha registrado la formación da la precipitación de fases de carburo/carbón nitrito que aparecen en forma de agujas y fase ? frágil. Con base en los resultados obtenidos, se puede concluir que la microestructura investigada no es idónea para aplicar la reparación por soldadura.

Odanovi?, Z.; Bla?i?, I.; Vra?ari?, D.; Grabulov, V.; Burzi?, M.; Katavi?, B.

2010-01-01

399

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

International Nuclear Information System (INIS)

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

2003-01-01

400

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

International Nuclear Information System (INIS)

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

1983-01-01

 
 
 
 
401

Corrosion of selected alloys in eutectic lithium-sodium-potassium carbonate at 900C  

Energy Technology Data Exchange (ETDEWEB)

There is an ongoing interest at the US Department of Energy in using molten salts as high temperature sensible heat storage media in advanced solar thermal systems. In this report, the compatibility of selected alloys in eutectic lithium-sodium-potassium carbonate, the salt that will be used in the near-term engineering experiments, has been evaluated at 900C. Several combinations of oxidation potential and acidity in the salt were used in the experiments. It was found that the extent of corrosion was dramatically lower for experiments conducted at high oxygen potential compared to experiments at low oxygen potential. For Inconel 600, Hastelloy N, and nickel the results indicated that corrosion rates substantially below 1 mm/year/side might reasonably be expected and that a reevaluation of alloys the showed poor corrosion resistance under low oxygen potential would be advisable.

Coyle, R.T.; Thomas, T.M.; Schissel, P.

1986-01-01

402

Effect of thermal neutron irradiation on mechanical properties of alloys for HTR core applications  

International Nuclear Information System (INIS)

An industrial heat of Hastelloy-X containing 2.3 ppm boron was creep-tested at 9000C after irradiating thermal neutrons by 6.6 x 1020 n/cm2 at temperatures 670 to 8800C in JMTR. Significant reduction in rupture life and ductility was observed, and large shift of accelerated deformation stage to short time side was also apparent at comparatively high stresses. Below about 2.2 kg/mm2, apparent relief from the degradation was seen. The elongation, however, was found to be due to the formation of numerous intergranular cracks in the premature stage of deformation. Based on the post irradiation tensile properties of several industrial alloys the degree of the ductility loss was found to be nearly dependent on the boron content of the alloys. The post irradiation tensile tests for a special low boron grade heat revealed the means of protecting materials from the effect to be feasible. (author)

1979-01-01

403

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

International Nuclear Information System (INIS)

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

1983-01-01

404

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

Energy Technology Data Exchange (ETDEWEB)

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

Krompholz, K.; Tipping, P.; Ullrich, G.

1984-04-01

405

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

Directory of Open Access Journals (Sweden)

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

Kolupaev Yu.Ye.; Yastreb T.O.; Karpets Yu.V.; Miroshnichenko N.N.

2011-01-01

406

Effects of exogenous calcium on the correlative physiological and biochemicalIndex on heat-resistance of citrus  

UK PubMed Central (United Kingdom)

Citrus leaves were used to examine the effect of exogenous Ca~(2+) pretreatment on the activity of SOD and the contents of soluble sugar, soluble protein and MDA. The results showed that under high temperature stress, the content of soluble sugar was distinctly different among varieties, which tended to rise with the increasing of sprayed Ca~(2+) concentration. The content of soluble protein and the activity of SOD tended to rise first, and then drop. When Ca~(2+) concentration was 10 mmol/L, SOD activity reached the maximum. Whileprotein content reached the maximum when Ca~(2+) concentration was 20mmol/L. When leaves of the citrus were sprayed with exogenous Ca~(2+), the sensitivity of different varieties to heat stress was clearly different using SOD as parameter. The higher SOD activity, the lower sensitivity citrus responded to it and the smaller increasing rate. The correlative coefficient was -0.9966. Under hightemperature stress,MDA contentwas distinctly different among varieties. It dropped first, and then rise with the increasing of Ca~(2+) concentration. When Ca~(2+) concentration was 20mmol/L, MDA content reached the minimum. These results showed that proper Ca~(2+) might strengthen citrus heat-resistance.

Zhang Jianxia; Li Xinguo; Sun Zhonghai

2005-01-01

407

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

Directory of Open Access Journals (Sweden)

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

2010-01-01

408

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

Science.gov (United States)

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

Maebara, Sunao; Goniche, Marc; Kazarian, Fabienne; Seki, Masami; Ikeda, Yoshitaka; Imai, Tsuyoshi; Beaumont, Bertrand

2005-05-01

409

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

International Nuclear Information System (INIS)

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

2012-01-01

410

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

International Nuclear Information System (INIS)

Highlights: ? The coarsening rate of the precipitates was accelerated by applied stress. ? The coalescence of martensite laths was accelerated by applied stress. ? The Laves phase and Z-phase were not observed after creep. ? The predicted size of MX precipitates by MatCalc agreed well with measured size. - Abstract: The effect of creep deformation on the microstructural evolution of an 11CrMoVNb ferritic heat resistant steel during high temperature creep tests was investigated. The creep test was performed within a temperatures range from 593 to 621 °C under different stress levels. For the detailed understanding of precipitate coarsening behavior, transmission electron microscopy (TEM) was used to analyze thin foils and replica films obtained from the crept specimens. The major precipitates were found to be M23C6, MX and Cr2N phases and there was no change in precipitation sequence during creep. Coarsening behavior of the precipitates and growth behavior of martensite laths of the crept specimens were carefully examined in both regions of the grip and gage parts of the specimens in order to identify the effect of creep deformation. On the whole, precipitate size increased with increasing creep rupture time. On the other hand, precipitate coarsening and martensite lath widening were pronounced in the gage part compared to those in the grip part. This suggests that the creep deformation accelerates the rates of precipitate coarsening and martensite lath widening.

2012-02-28

411

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

International Nuclear Information System (INIS)

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

1983-01-01

412

[Superplastic forming of titanium alloy denture base  

UK PubMed Central (United Kingdom)

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

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

1989-03-01