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Sample records for carburization

  1. Accelerated Gas Carburizing (URX Gas Carburizing)

    Institute of Scientific and Technical Information of China (English)

    Yoshikazu Shimosato; Mamoru Kamitani; Hiroyuki Nakatsu

    2004-01-01

    URX gas carburizing is an accelerated gas carburizing method with 50% CO + 50% H2 gas which comes from CH4 gas + CO2 gas. By using this gas composition, the carburizing reaction rate increases to the maximum and the controllability of carbon potential improves. A carbon mass flow rate is the product of the carburizing reaction rate multiplied by the difference of carbon percent between carbon potential of the gas and the carbon content of the surface of treated steel parts. We have obtained excellent results from the experimental tests at our laboratory as mentioned bellow. 1)Carburizing time can be shortened by 40% for 0.5 - 0.9 mm effective case depth. 2) Uniform carburizing case depth 3) Less internal oxidation with the same case depth. We have already developed the new roller hearth type continuous carburizing furnace and the new URX gas generator.

  2. Quality of carburizers and its influence on carburization process

    Directory of Open Access Journals (Sweden)

    K. Janerka

    2009-07-01

    Full Text Available In the papers issue of production the synthetic cast iron obtaining on the basis of only steel scrap and carburizing materials are presented. Natural graphite, synthetic graphite, anthracite, petroleum coke, foundry coke and charcoal were used to carburization. Examinations covered evaluation of used carburizers taking into account chemical composition; carbon, sulphur and nitrogen content have been analyzed. Obtained effectiveness of carburization with method of inserting carburizing material into charge in solid, were especially taken into considerations. The comparison between mechanical properties (tensile strength and hardness of produced synthetic cast iron and cast iron obtained on the basis of pig iron have been carried out.

  3. Acetylene Vacuum Carburizing

    Institute of Scientific and Technical Information of China (English)

    Hitoshi Iwata

    2004-01-01

    Almost 30 years has passed since the publication of materials on vacuum carburizing technology, and is attracting a great deal of attention as a technology capable of being used as a substitute for gas carburizing technology.However, the technology was not popular except in specific fields. The main reason for this is due to a variety of harmful influences accompanying the sooting problems caused by CH4 or C3H8. We have succeeded in that the occurrence of sooting was suppressed by utilizing acetylene, at extremely low pressure for carburizing (below 1 kPa). This process is now showing the excellent quality and prospects for this technology in terms of quality, economy and safety. At present almost 70 practical mass production furnaces are used in production lines, in Japan and abroad. At this time, we will report summary of the present acetylene vacuum carbufizing process and the actual results obtained by these acetylene vacuum carbufizing furnaces for mass production.

  4. The properties and structure of the carburizers

    Directory of Open Access Journals (Sweden)

    K. Janerka

    2010-01-01

    Full Text Available The results of examinations of the carburizers for foundry industry were presented in the article. The commonly used carburizers were selected for the experiments (anthracite, natural and synthetic graphite, petroleum coke of various grades, cupola coke and charcoal as well. The experiments consist of bulk and standard density, screen analysis (on the basis of it the equivalent diameter was calculated and the microstructure of the carburizers measurements. The chemical composition and basic properties of carburizers were described too.

  5. Effects of carburization time and temperature on the mechanical properties of carburized mild steel, using activated carbon as carburizer

    Directory of Open Access Journals (Sweden)

    Fatai Olufemi Aramide

    2009-01-01

    Full Text Available Due to the complexity of controlling parameters in carburization, there has been relatively little work on process variables during the surface hardening process. This work focuses on the effects of the carburizing temperature and time on the mechanical properties of mild steel carburized with activated carbon, at 850, 900 and 950 ºC, soaked at the carburizing temperature for 15 and 30 minutes, quenched in oil, tempered at 550 ºC and held for 60 minutes. Prior carburization process, standard test samples were prepared from the as received specimen for tensile and impact tests. After carburization process, the test samples were subjected to the standard test and from the data obtained, ultimate tensile strength, engineering strain, impact strength, Youngs' moduli were calculated. The case and core hardness of the carburized tempered samples were measured. It was observed that the mechanical properties of mild steels were found to be strongly influenced by the process of carburization, carburizing temperature and soaking time at carburizing temperature. It was concluded that the optimum combination of mechanical properties is achieved at the carburizing temperature of 900 ºC followed by oil quenching and tempering at 550 ºC.

  6. The rate and effectiveness of carburization to the sort of carburizer

    Directory of Open Access Journals (Sweden)

    K. Janerka

    2007-12-01

    Full Text Available The obtaining of demanded carbon contents during melting the cast iron with bounded pig iron’s portion is important problem for many foundries. There are searched the effective methods and carburizers, which would ensure obtaining of big carbon increases with great repeatability as quick as possible. The aim of presented researches was definition of influence of essential factors characterized the carburization and the sort of carburizer on the rate and effectiveness of process. The cast iron melts are presented only on the basis of steel scrap with the portion of graphitoidal, coke and anthracite carburizers. Two methods of carburization are taken into consideration during the experiments were carried out: the addition of carburizer to charge in solid in the initial period of melting and addition of carburizer on surface of liquid metal . The obtained researches results and their analyze allow to choose the corresponding method and the sort of carburizer. One can state, that the best carburizer is synthetic graphite, if the rate and effectiveness of process is considerate and the best method of carburization in the electric inductive furnace is addition of carburizer to charge in solid. In the subsequent part of researches the analyze of influence of carburizer on the structure of grey cast iron and ductile cast iron. The initial researches has showed the differences in obtained structures of synthetic cast iron melted only on the basis of steel scrap and defined kind of carburizer.

  7. Pack Carburization of Mild Steel, using Pulverized Bone as Carburizer: Optimizing Process Parameters

    Directory of Open Access Journals (Sweden)

    Joseph Olatunde BORODE

    2010-12-01

    Full Text Available Investigation was conducted into the mechanical properties of mild steel subjected to packed carburization treatment using pulverized bone as the carburizer, carburized at 850C, 900C and 950C, soaked at the carburizing temperature for 15 minutes and 30 minutes, quenched in oil and tempered at 550C. Prior carburization process, standard test samples were prepared from the as received specimen for tensile and impact tests. After carburization process, the test samples were subjected to the standard test and from the data obtained, ultimate tensile strength, engineering strain, impact strength, Youngs moduli were calculated. The case and core hardness of the carburized tempered samples were measured. It was observed that the mechanical properties of mild steels were found to be strongly influenced by the process of carburization, carburizing temperature and soaking time at carburizing temperature. It was concluded that the sample carburized at 900C soaked for 15 minutes and the one carburized at 850C soaked for 30 minutes followed by oil quenching and tempering at 550C were better because they showed a trend of hard case with softer core.

  8. The properties and structure of the carburizers

    OpenAIRE

    K. Janerka; J. Jezierski; M. Pawlyta

    2010-01-01

    The results of examinations of the carburizers for foundry industry were presented in the article. The commonly used carburizers were selected for the experiments (anthracite, natural and synthetic graphite, petroleum coke of various grades), cupola coke and charcoal as well. The experiments consist of bulk and standard density, screen analysis (on the basis of it the equivalent diameter was calculated) and the microstructure of the carburizers measurements. The chemical composition and basic...

  9. Vacuum gas carburizing – fate of hydrocarbons

    OpenAIRE

    Khan, Rafi Ullah

    2008-01-01

    This work focuses on gaseous reactive flows in ideal and non-ideal reactors. The objective of this research is the development of models for the numerical simulation of homogeneous reactive flows under vacuum carburizing conditions of steel with propane and acetylene. These models can be used for further investigations of heterogeneous reactions during vacuum carburizing of steel to predict the carbon flux on the complex shaped steel parts to understand and, eventually, optimize the behavior ...

  10. Carburizer Effect on Cast Iron Solidification

    Science.gov (United States)

    Janerka, Krzysztof; Kondracki, Marcin; Jezierski, Jan; Szajnar, Jan; Stawarz, Marcin

    2014-06-01

    This paper presents the effect of carburizing materials on cast iron solidification and crystallization. The studies consisted of cast iron preparation from steel scrap and different carburizers. For a comparison, pig iron was exclusively used in a solid charge. Crystallization analysis revealed the influence of the carburizer material on the crystallization curves as well as differences in the solidification paths of cast iron prepared with the use of different charge materials. The carburizers' influence on undercooling during the eutectic crystallization process was analyzed. The lowest undercooling rate was recorded for the melt with pig iron, then for synthetic graphite, natural graphite, anthracite, and petroleum coke (the highest undercooling rate). So a hypothesis was formulated that eutectic cells are created most effectively with the presence of carbon from pig iron (the highest nucleation potential), and then for the graphite materials (crystallographic similarity with the carbon precipitation in the cast iron). The most difficult eutectic crystallization is for anthracite and petroleum coke (higher undercooling is necessary). This knowledge can be crucial when the foundry plant is going to change the solid charge composition replacing the pig iron by steel scrap and the recarburization process.

  11. Simultaneous oxidation and carburization under oxyfuel conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kranzmann, Axel; Schulz, Wencke [Federal Institute for Materials Research and Testing, Berlin (Germany). Div. V.1 Composition and Microstructure of Engineering Materials; Huenert, Daniela [National Institute for Standards and Technology, Gaithersburg, MD (United States). Group 855.13 Thermodynamics and Kinetics

    2010-06-15

    The combustion of coal in CO{sub 2}-reduced oxyfuel power plants requires creep resistant and corrosion resistant materials which can withstand high temperatures up to 600 C (873 K) and CO{sub 2}-rich atmospheres. Among the heat resistant materials, the 9-12 % chromium steels have been proven to resist high wall temperatures in conventional power plants and are suitable as membrane walls, superheaters and steam piping. During oxyfuel combustion a flue gas is generated which consists mainly of H{sub 2}O (x{sub H{sub 2}}{sub O}=0.3) and CO{sub 2} (x{sub CO{sub 2}}=0.7). The present paper is focused on the corrosion of 9-12 % chromium steels under oxyfuel conditions in a temperature range between 550 C (823 K) and 625 C (898 K). Depending on the chromium content of the 9-12 % chromium steels, carburization of the base material, perlite formation and carbide formation were observed. Alloys with lower chromium content form a non-protective oxide scale with perlite at the scale-alloy interface. Steels with 12 % chromium have a small growing oxide scale with enlarged M{sub 23}C{sub 6} particles at the scale-alloy interface. The carburization of the base material is found to be increased for the 9 % Cr steel. Higher pressure of the flue gas results in the formation of less resistant scales and causes accelerated carburization of the base materials. However, the carburization has an impact on the mechanical properties at the surface and leads to an embrittlement, which is deleterious during thermal cycling. Oxidation kinetics, phase analysis of the scale (transmission electron microscope) and carburization depths (microprobe) of the base materials are presented. (orig.)

  12. AN INVESTIGATION OF RETAINED AUSTENITE CONTENTS IN CARBURIZED SAE 8620 STEEL

    OpenAIRE

    2010-01-01

    ABSTRACT In this study, retained austenite contents in carburized  SAE 8620 (21NiCrMo2) steel were investigated. Carburizing programs were carried out in gas atmosphere at 940°C. X-ray diffraction was used to determine retained austenite contents in the case-hardened microstructures of the carburized specimens. Test results indicated that maximum retained austenite contents at the microstructures of the carburized specimens that carburized 45 minute, 3 h and 5 h carburizing times at ...

  13. Carburizer particle dissolution in liquid cast iron – computer simulation

    Directory of Open Access Journals (Sweden)

    D. Bartocha

    2010-01-01

    Full Text Available In the paper issue of dissolution of carburizing materials (anthracite, petroleum coke and graphite particle in liquid metal and its computer simulation are presented. Relative movement rate of particle and liquid metal and thermophsical properties of carburizing materials (thermal conductivity coefficient, specific heat, thermal diffusivity, density are taken into consideration in calculations. Calculations have been carried out in aspect of metal bath carburization in metallurgical furnaces.

  14. Numerical Simulation on Carburizing and Quenching of Gear Ring

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The carburizing process of the gear ring was simulated by taking into account the practical carburizing and quenching techniques of the gear ring and by solving the diffusion equation. The carbon content distribution in the carburized layer was obtained. Based on the results, the quenching process of the gear ring was then simulated using the metallic thermodynamics and FEM; it was found that the carburization remarkably affects the quenching process.Microstructures and stress distributions of the gear ring in the quenching process were simulated, and the results are confirmed by experiments.

  15. Packed bed carburization of tantalum and tantalum alloy

    Science.gov (United States)

    Lopez, Peter C.; Rodriguez, Patrick J.; Pereyra, Ramiro A.

    1999-01-01

    Packed bed carburization of a tantalum or tantalum alloy object. A method for producing corrosion-resistant tantalum or tantalum alloy objects is described. The method includes the steps of placing the object in contact with a carburizing pack, heating the packed object in vacuum furnace to a temperature whereby carbon from the pack diffuses into the object forming grains with tantalum carbide along the grain boundaries, and etching the surface of the carburized object. This latter step removes tantalum carbides from the surface of the carburized tantalum object while leaving the tantalum carbide along the grain boundaries.

  16. Magnetic Barkhausen Noise in quenched carburized steels

    Energy Technology Data Exchange (ETDEWEB)

    De Campos, M F; Santos, R; Da Silva, F S; Lins, J F C [PUVR- Universidade Federal Fluminense, Av dos Trabalhadores 420, Vila Santa Cecilia, Volta Redonda, RJ, 27255-125 (Brazil); Franco, F A; Ribeiro, S B; Padovese, L R, E-mail: mcampos@metal.eeimvr.uff.br, E-mail: mfdcampo@uol.com.br [Escola Politecnica, Universidade de Sao Paulo, Sao Paulo, SP (Brazil)

    2011-07-06

    Steels with different carbon content, 0.11%C and 0.48%C were submitted to a heat treatment for carburization in the surface. The samples were analyzed after several types of heat treatment, including quenching for producing martensite. The Magnetic Barkhausen Noise (MBN) is directly related to the microstructure. Samples with lower carbon content, have ferrite, a constituent where domain walls can move freely and present higher amplitude in the envelope of MBN. It is also found that the MBN peaks are quite distinct for the samples with martensite, which have lower permeability, and the results suggest that domain rotation contributes as mechanism for reversal of magnetization in martensite. The results also indicate that MBN is very suitable for monitoring the carburizing heat treatment.

  17. Magnetic Barkhausen Noise in quenched carburized steels

    Science.gov (United States)

    de Campos, M. F.; Franco, F. A.; Santos, R.; da Silva, F. S.; Ribeiro, S. B.; Lins, J. F. C.; Padovese, L. R.

    2011-07-01

    Steels with different carbon content, 0.11%C and 0.48%C were submitted to a heat treatment for carburization in the surface. The samples were analyzed after several types of heat treatment, including quenching for producing martensite. The Magnetic Barkhausen Noise (MBN) is directly related to the microstructure. Samples with lower carbon content, have ferrite, a constituent where domain walls can move freely and present higher amplitude in the envelope of MBN. It is also found that the MBN peaks are quite distinct for the samples with martensite, which have lower permeability, and the results suggest that domain rotation contributes as mechanism for reversal of magnetization in martensite. The results also indicate that MBN is very suitable for monitoring the carburizing heat treatment.

  18. Computation of carbon concentration curves in vacuum carburizing of steels

    Science.gov (United States)

    Semenov, M. Yu.; Smirnov, A. E.; Ryzhova, M. Yu.

    2013-05-01

    The boundary conditions of the diffusion problem in parametric form are determined on the basis of an experimental study of formation of carbon-saturated layers in vacuum carburizing. The boundary conditions are applied in a model of a process with cyclic modes of carburizing. Adequacy of the developed model is confirmed.

  19. Gas-Carburizing Kinetics of a Low-Alloy Steel

    Science.gov (United States)

    Nobili, Luca; Cavallotti, Pietro; Pesetti, Mariella

    2010-02-01

    Gas-carburizing kinetics of a low-alloy steel (Pyrowear 53) was investigated by thermogravimetric experiments. Kinetic curves were modeled by adapting the approximate integral method, and the diffusion coefficient of carbon as well as the rate constant of the surface reaction were estimated. These parameters were evaluated after several carburizing procedures, which differ from each other in the surface treatments performed before the carburizing step. It is known that the carbon enrichment is low when this steel is carburized without any pretreatment, and this behavior was found to be related to a low value of carbon diffusivity. The interaction between the selective oxidation of alloying elements by the carburizing atmosphere and carbon diffusion is discussed. The pretreatment procedures investigated in this work consist of different combinations of oxidation, reduction, and grit-blasting processes. The most effective procedures involve oxidation in dry air or oxidation in wet air followed by grit blasting.

  20. Enhancement of Stainless Steel's Mechanical Properties via Carburizing Process

    Science.gov (United States)

    Ahmad, S.; Alias, S. K.; Abdullah, B.; Hafiz Mohd Bakri, Mohd.; Hafizuddin Jumadin, Muhammad; Mat Shah, Muhammad Amir

    2016-11-01

    Carburizing process is a method to disperse carbon into the steel surface in order to enhance its mechanical properties such as hardness and wear resistance. This paper study investigates the effect of carburizing temperature to the carbon dispersion layer in stainless steel. The standard AISI 304 stainless steel was carburized in two different temperatures which were 900°C and 950°C. The effect of carbon dispersion layers were observed and the results indicated that the increasing value of the average dispersion layer from 1.30 mm to 2.74 mm thickness was found to be related to increment of carburizing holding temperature . The increment of carbon thickness layer also resulted in improvement of hardness and tensile strength of carburized stainless steel.

  1. Tribological and corrosion behaviors of carburized AISI 4340 steel

    Science.gov (United States)

    Thong-on, Atcharawadi; Boonruang, Chatdanai

    2016-01-01

    AISI 4340 steel is widely used in automotive and aircraft industries as gear components. In such applications, surface hardening processes such as carburizing are required in order to improve the life time of the components. There are many studies showing the tribological behavior of the carburized steel, but the corrosion behavior has not yet been clarified. This paper reports on both tribological and corrosion behaviors of the carburized AISI 4340 steel. Factor associated with carburizing, such as the quantities of deposited carbon, dissolved carbon, and formed Cr23C6 and Fe3C, affect the tribological and corrosion behaviors of the steel by improving hardness, friction, lubrication, and wear resistance; but corrosion resistance is reduced. The dissolved carbon affects the formation of the oxide layer of the carburized steel, by obstructing the continuous oxide layer formation and by decreasing the chromium content of the steel, leading to the decrease in the corrosion resistance of the steel.

  2. Evaluation of Carburized and Ground Face Gears

    Science.gov (United States)

    Lewicki, David G.; Handschuh, Robert F.; Heath, Gregory F.; Sheth, Vijay

    1999-01-01

    Experimental durability tests were performed on carburized and ground AIS19310 steel face gears. The tests were in support of a Defense Advanced Research Projects Agency (DARPA) Technology Reinvestment Program (TRP) to enhance face-gear technology. The tests were conducted in the NASA Glenn spiral-bevel-gear/face-gear test facility. Tests were run at 2300 rpm face gear speed and at loads of 64, 76, 88, 100, and 112-percent of the design torque of 377 N-m (3340 in-lb). The carburized and ground face gears demonstrated the required durability when run for ten-million cycles at each of the applied loads. Proper installation was critical for the successful operation of the spur pinions and face gears. A large amount of backlash produced tooth contact patterns that approached the inner-diameter edge of the face-gear tooth. Low backlash produced tooth contact patterns that approached the outer-diameter edge of the face-gear tooth. Measured backlashes in the range of 0.178 to 0.254 mm (0.007 to 0.010 in) produced acceptable tooth contact patterns.

  3. Final Scientific Report - "Novel Steels for High Temperature Carburizing"

    Energy Technology Data Exchange (ETDEWEB)

    McKimpson, Marvin G.; Liu, Tianjun; Maniruzzaman, Md

    2012-07-27

    This program was undertaken to develop a microalloy-modified grade of standard carburizing steel that can successfully exploit the high temperature carburizing capabilities of current commercial low pressure (i.e. 'vacuum') carburizing systems. Such steels can lower the amount of energy required for commercial carburizing operations by reducing the time required for deep-case carburizing operations. The specific technical objective of the work was to demonstrate a carburizing steel composition capable of maintaining a prior austenite grain size no larger than ASTM grain size number 5 after exposure to simulated carburizing conditions of 1050 C for 8 hr. Such thermal exposure should be adequate for producing carburized case depths up to about 2 mm. Such carburizing steels are expected to be attractive for use across a wide range of industries, including the petroleum, chemical, forest products, automotive, mining and industrial equipment industries. They have potential for reducing energy usage during low pressure carburizing by more than 25%, as well as reducing cycle times and process costs substantially. They also have potential for reducing greenhouse gas emissions from existing low pressure carburizing furnaces by more than 25%. High temperature carburizing can be done in most modern low pressure carburizing systems with no additional capital investment. Accordingly, implementing this technology on carburizing furnaces will provide a return on investment significantly greater than 10%. If disseminated throughout the domestic carburizing community, the technology has potential for saving on the order of 23 to 34 trillion BTU/year in industrial energy usage. Under the program, two compositions of microalloyed, coarsening-resistant low alloy carburizing steels were developed, produced and evaluated. After vacuum annealing at 1050oC for 8 hrs and high pressure gas quenching, both steels exhibited a prior austenite ASTM grain size number of 5.0 or finer

  4. Computer simulation of carburizers particles heating in liquid metal

    Directory of Open Access Journals (Sweden)

    K. Janerka

    2010-01-01

    Full Text Available In this article are introduced the problems of computer simulation of carburizers particles heating (anthracite, graphite and petroleum coke, which are present in liquid metal. The diameter of particles, their quantity, relative velocity of particles and liquid metal and the thermophysical properties of materials (thermal conductivity, specific heat and thermal diffusivity have been taken into account in calculations. The analysis has been carried out in the aspect of liquid metal carburization in metallurgical furnaces.

  5. Electrochemical corrosion behavior of the carburized porous TiAl alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Cuijiao [Hunan University of Technology, Zhuzhou, Hunan 412000 (China); Yang, Junsheng [Wuhan Polytechnic University, Wuhan, Hubei 430023 (China); He, Yuehui, E-mail: yuehui@mail.csu.edu.cn [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Ming, XingZu [Hunan University of Technology, Zhuzhou, Hunan 412000 (China)

    2015-01-15

    Highlights: • Ti{sub 2}AlC phase forms on porous TiAl alloy in a carburizing atmosphere. • The carburized sample at 1203 K for 10 h has continuous carburized layers. • Carburization can improve corrosion resistance of the porous TiAl alloy. • The passive film of the carburized sample at 1203 K for 10 h is very stable. - Abstract: Carburization was carried out to improve corrosion resistance of porous Ti–46.5 Al (at.%) intermetallic compound. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were applied to analyze the carburized layers. Electrochemical corrosion behavior of the untreated and the carburized samples were investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and open circuit potential. The results reveal that the continuous and thick carburized layers form after carburization treatment at 1203 K for 10 h, whose main phase is a functional complex ceramic phase, Ti{sub 2}AlC. Carburization can improve corrosion resistance of the porous TiAl alloy. Among the carburized samples, the carburized one at 1203 K for 10 h presents the highest corrosion resistance and has the most stable oxide film.

  6. Mechanical properties of the CO{sub 2} free vacuum carburized in SCM415H

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Jae Hyuk; Ro, Seung Hoon; Lee, Jong Hyung; Lee, Chang Hun; Yang, Seong Hyeon [Kumoh Nat' l Institute of Technology, Gumi (Korea, Republic of)

    2012-09-15

    Vacuum carburizing is supposed to be the superior process to the gas carburizing. However, the vacuum carburizing has the stage in which hydrocarbon gas is supplied into the furnace to be pyrolysis, and consequently the stable heat treatment is hard to achieve due to the soot from the hydrocarbon pyrolysis. Recently, many studies have been made which utilize acetylene gas to overcome this defects. In this paper, the carburizing and the diffusion periods have been selected based on the Harris experimental formula, and the mechanical properties of the vacuum carburized specimen have been compared with those of the gas carburized SCM415H specimen to identify the feasibility of the CO{sub 2} free vacuum carburizing process. The result showed that the vacuum carburized materials used have no oxidization of the grain boundaries, and show the 29.8% higher effective hardness depth and the acceptable tensile strength.

  7. Gradient boride layers formed by diffusion carburizing and laser boriding

    Science.gov (United States)

    Kulka, M.; Makuch, N.; Dziarski, P.; Mikołajczak, D.; Przestacki, D.

    2015-04-01

    Laser boriding, instead of diffusion boriding, was proposed to formation of gradient borocarburized layers. The microstructure and properties of these layers were compared to those-obtained after typical diffusion borocarburizing. First method of treatment consists in diffusion carburizing and laser boriding only. In microstructure three zones are present: laser borided zone, hardened carburized zone and carburized layer without heat treatment. However, the violent decrease in the microhardness was observed below the laser borided zone. Additionally, these layers were characterized by a changeable value of mass wear intensity factor thus by a changeable abrasive wear resistance. Although at the beginning of friction the very low values of mass wear intensity factor Imw were obtained, these values increased during the next stages of friction. It can be caused by the fluctuations in the microhardness of the hardened carburized zone (HAZ). The use of through hardening after carburizing and laser boriding eliminated these fluctuations. Two zones characterized the microstructure of this layer: laser borided zone and hardened carburized zone. Mass wear intensity factor obtained a constant value for this layer and was comparable to that-obtained in case of diffusion borocarburizing and through hardening. Therefore, the diffusion boriding could be replaced by the laser boriding, when the high abrasive wear resistance is required. However, the possibilities of application of laser boriding instead of diffusion process were limited. In case of elements, which needed high fatigue strength, the substitution of diffusion boriding by laser boriding was not advisable. The surface cracks formed during laser re-melting were the reason for relatively quickly first fatigue crack. The preheating of the laser treated surface before laser beam action would prevent the surface cracks and cause the improved fatigue strength. Although the cohesion of laser borided carburized layer was

  8. Analysis of methods of carburizing of gears from heat-resistant steels

    Science.gov (United States)

    Ryzhov, N. M.; Fakhurtdinov, R. S.; Smirnov, A. E.; Fomina, L. P.

    2010-11-01

    Four methods of carburizing are compared with respect to the most significant factor, i.e., stability of maintenance of the specified parameters of carburized layer in hardening of gears from heat-resistant steels. The process advantages of vacuum carburizing (at low pressure) are shown.

  9. Effect of carbon on tribological property of plasma carburized TiAl based alloy

    Institute of Scientific and Technical Information of China (English)

    LIU Xiao-ping; TIAN Wen-huai; GUO Chao-li; HE Zhi-yong; XU Zhong

    2006-01-01

    Plasma carburization at two different methane-to-argon gas ratios (5:5 and 6:5) was carried out on the cast TiAl based alloy of Ti-46.5Al-2.5V-1Cr (mole fraction, %) in order to enhance its wear resistance. The results show that after carburization under both carburizing atmospheres, Ti2AlC and TiC are the main carbides in the carburized layer and the value of surface hardness reaches more than HK 822, but for the carburized TiAl treated at CH4-Ar of 5-5, the surface carbon concentration is higher and the carburized depth is slightly thicker than that of alloy carburized at CH4-Ar of 6-5. The result of the ball-on-disk test against hardening-steel counter bodies shows that the wear resistance of the TiAl based alloy carburized under two different carburizing atmospheres is improved compared with non-carburized TiAl. The tribological property is related to the carbon content, and the carburized layer obtained at CH4:Ar of 5:5 possesses a stable friction coefficient, lower volume loss or wear rate and narrow wear scar. The characteristic of the carburized layer was examined by using optical microscopy, glow discharge spectrum and micro-hardness tester.

  10. Materials and Process Design for High-Temperature Carburizing: Integrating Processing and Performance

    Energy Technology Data Exchange (ETDEWEB)

    D. Apelian

    2007-07-23

    The objective of the project is to develop an integrated process for fast, high-temperature carburizing. The new process results in an order of magnitude reduction in cycle time compared to conventional carburizing and represents significant energy savings in addition to a corresponding reduction of scrap associated with distortion free carburizing steels.

  11. Carburizing of Duplex Stainless Steel (DSS) Under Compression Superplastic Deformation

    Science.gov (United States)

    Ahamad, Nor Wahida; Jauhari, Iswadi

    2012-12-01

    A new surface carburizing technique which combines superplastic deformation with superplastic carburizing (SPC) is introduced. SPC was conducted on duplex stainless steel under compression mode at a fixed 0.5 height reduction strain rates ranging from 6.25 × 10-5 to 1 × 10-3 s-1 and temperature ranging from 1173 K to 1248 K (900 °C to 975 °C). The results are compared with those from conventional and non-superplastic carburizing. The results show that thick hard carburized layers are formed at a much faster rate compared with the other two processes. A more gradual hardness transition from the surface to the substrate is also obtained. The highest carburized layer thickness and surface hardness are attained under SPC process at 1248 K (975 °C) and 6.25 × 10-5 s-1 with a value of (218.3 ± 0.5) μm and (1581.0 ± 5.0) HV respectively. Other than that, SPC also has the highest scratch resistance.

  12. Effects of Carburized Parts on Residual Stresses of Thin-Rimmed Spur Gears with Symmetric Web Arrangements Due to Case-Carburizing

    Institute of Scientific and Technical Information of China (English)

    Kouitsu Miyachika; Wei-Dong Xue; Satoshi Oda; Hidefumi Mada; Hiroshige Fujio

    2004-01-01

    This paper presents a study on effects of carburized parts on residual stresses of thin-rimmed spur gears with symmetric web arrangements due to the case-carburizing. The carbon content of each element of the FEM gear model due to carburizing was obtained according to Vickers hardness Hv - carbon content C% and C% - d (distance from surface)charts. A heat conduction analysis and an elastic-plastic stress analysis during the case-carburizing process of thin-rimmed spur gears with symmetric web arrangements were carried out for various case-carburizing conditions by using the three-dimensional finite element method (3D-FEM) program developed by authors, and then residual stresses were obtained.The effects of the carburized part, the web structure, and the rim thickness on the residual stress were determined.

  13. The Corrosion Behavior of Carburized Aluminum Using DC Plasma

    Directory of Open Access Journals (Sweden)

    Somayeh Pirizadhejrandoost

    2012-01-01

    Full Text Available Because of the outstanding properties of aluminum, it is widely used in today's advanced technological world. However, its insufficient wear resistance limits its use for commercial and industrial applications. In this study, we performed DC diode plasma carburizing of aluminum in the gas composition of CH4–H2 (20–80% and at a temperature of about 350°C for 4 and 8 hours. The corrosion properties of the untreated and plasma-carburized samples were evaluated using anodic polarization tests in 3 N HCl solution according to ASTM: G5-94. The metallurgical characteristics were then investigated using XRD and SEM. The results showed that the carburizing process improves the corrosion resistance of treated specimens at low temperature.

  14. Bending Fatigue of Carburized Steel at Very Long Lives

    Science.gov (United States)

    Nelson, D. V.; Long, Z.

    2016-01-01

    The bending fatigue behavior of two carburized steels is investigated for lives between approximately 105 and 108 cycles. Cracks are observed to start at sub-surface inclusions and develop features on fracture surfaces resembling "fish eyes" in appearance. This type of sub-surface cracking tends to govern fatigue strength at long lives. Previous studies of "fish eye" fatigue in carburized steel have been relatively few and have mainly considered failures originating at depths beneath a carburized case, where compressive residual stresses are minimal and hardness values approach those in the core. This study provides fatigue data for cracks originating within cases at various depths where compressive residual stresses are substantial and hardness is much higher than in the core. Fatigue strength is predicted by a simple model, accounting for the influence of residual stresses and hardness values at the different depths at which cracks started. Predictions of fatigue strength are compared with data generated in this study.

  15. Investigation The Mechanical Properties of Carburized Low Carbon Steel

    Directory of Open Access Journals (Sweden)

    Dr. Mohammed Abdulraoof Abdulrazzaq

    2016-09-01

    Full Text Available microstructure, mechanical properties; hardness and wear resistance has been investigated taken different temperatures; (850, 900, and 950 ˚C with constant time (2 hr of carburizing process. The experimental work shows that at carburizing temperature (850 ˚C, the hardness was increases from the inside to outside of specimen from ( 102 to HV 250., while increases for temperatures (900 and 950 ˚C from (105 to 272 HV, and (115 to 192 HV respectively. This experiment also been conducted for wear resistance for harder specimen which was at 950 ˚C carburized sample for three times (2, 4 and, 6 hr and the wear rate was (9.99*10-6 g/m at (2 hr, and for (4 hr it was (12.7*10-6 g/m and at (6 hr it was (15.13*10-6 g/m.

  16. The Influence of Carburizing Parameters on Carbon Transfer Coefficient

    Institute of Scientific and Technical Information of China (English)

    Tadeusz Sobusiak

    2004-01-01

    Definition of coefficient of carbon transfer in European Standard (EN 10052) is presented as: "Mass of carbon transferred from carburizing medium into the steel, per unit surface area per second for a unit difference between the carbon potential, and actual surface carbon content".In this paper, a model is presented of carbon transfer from endothermic atmospheres to carbon steel. The carbon transfer coefficient values were determined experimentally by the foil technique and on specimens, taking into account the following parameters: chemical composition of atmospheres, carbon potential, temperature and time of the carburizing process. Some examples of the variation of the carbon transfer coefficient for two steps of the carburizing process,including soaking before quenching, are given, based on results obtained. The effect of carbon transfer coefficient on carbon content at the steel surface is given.

  17. On the Plasma (ion) Carburized Layer of High Nitrogen Austenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    Y. Ueda; N. Kanayama; K. Ichii; T. Oishi; H. Miyake

    2004-01-01

    The manganese concentration of austenitic stainless steel decreases from the inner layer towards the surface of the plasma (ion) carburized layer due to the evaporation of manganese from the specimen surface. The carbon concentration in the carburized layer is influenced by alloyed elements such as Ct, Ni, Si, and Mo, as well as Nitrogen. This study examined the effects of nitrogen on the properties of the carburized layer of high nitrogen stainless steel. Plasma (ion)carburizing was carried out for 14.4 ks at 1303 K in an atmosphere of CH4+H2 gas mixtures under a pressure of 350 Pa. The plasma carburized layer of the high nitrogen stainless steel was thinner than that of an austentric stainless steel containing no nitrogen. This suggested that the nitrogen raised the activity of carbon in the plasma carburized layer, GDOES measurement indicated that the nitrogen level in the layer did not vary after plasma (ion) carburizing.

  18. MPPA-SSI12 automated module facility for "liquid" carburizing

    Science.gov (United States)

    Syropyatov, V. Ya.

    2011-10-01

    An automated module facility of model MPPA-SSi12 for making controlled endothermic furnace atmospheres based on carbon-containing liquids is described. The facility is used for batching and feeding process liquids into carburizing shaft electric furnaces with automatic control of the carbon potential by changing the flow of added air.

  19. Contribution of shot peening on carburized or carbonitrided parts

    Science.gov (United States)

    Renaud, P.; Bristiel, P.; Barrallier, L.; Desvignes, M.; Kubler, R.

    2011-01-01

    The main purpose of car manufacturers is to design parts which are light and at the same time very resistant to fatigue efforts. Surface treatments are effective means to deal with this compromise. They bring surface hardness and introduce compressive residual stresses. This experimental study focuses on the influence of shot peening on parts initially treated by carburizing or carbonitriding.

  20. Study on Carburizing Kinetics of Low-carbon Steel at High-temperature and Short-term

    Institute of Scientific and Technical Information of China (English)

    Lu Sheng; Xiao Nianxin; Zhang Hailong

    2007-01-01

    In this paper, the carburizing kinetics of low-carbon steel at high-temperature and short-term in liquid cast-iron were studied by metallographic microscope, chemical analysis and so on, and the microstructure of carburized layer was also analyzed. The results show that the carburizing rate of low-carbon steel at high-temperature and short-term is so fast, and the microstructure of carburized layer possess higher carbon content, and cementite, pearlite and ferrite exist in carburized layer structure simultaneously. Besides, the kinetic equations of permeating layer forming have been presented, and the carburizing mechanism was preliminary discussed also.

  1. Double Glow Plasma Hydrogen-free Carburizing on Commercial Purity Titanium

    Institute of Scientific and Technical Information of China (English)

    ZHANG Gaohui; PAN Junde; HE Zhiyong; ZHANG Pingze; GAO Yuan; XU Zhong

    2005-01-01

    A carburized layer with special physical and chemical properties was formed on the surface of commercial purity titanium by a double glow plasma hydrogen-free carburizing technique. High-purity netlike solid graphite was used as a raw material and commercial purity titanium was used as the substrate material. Argon gas was used as the working gas. The carburized layer can be obviously observed under a microscope. X-ray diffraction indicates that TiC phase with higher hardness and dissociate state carbon phase was formed in the carburized layer. The glow discharge spectrum (GDS) analysis shows that the carbon concentration distributes gradiently along the depth of carburized layer. The surface hardness of the substrate increases obviously. The hardness distributes gradiently from the surface to inner of carburized layer. The friction coefficient reduces by more than 1/2, the ratio wear rate decreases by above three orders of magnitude. The wear resistance of the substrate material is improved consumedly.

  2. Graphene Growth via Carburization of Stainless Steel and Application in Energy Storage

    Science.gov (United States)

    2011-01-01

    1697© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim wileyonlinelibrary.comsmall 2011, 7, No. 12, 1697–1700 1. Introduction Carburization is a...in order to achieve few-layers-thick graphene on stainless steel (SS) substrates. Though the carburization process is similar to the chemi cal...vapor deposition (CVD) tech- nique, which is generally used for growth of graphene on Graphene Growth via Carburization of Stainless Steel and

  3. Hydrogen uptake during Carburizing and Effusion of Hydrogen at Room Temperature and during Tempering

    OpenAIRE

    Khodahami, Maryam

    2013-01-01

    The carburizing atmosphere during the case hardening process contains a large proportion of hydrogen. Due to the rapid diffusion of hydrogen a high amount of hydrogen can be absorbed by the carburizing component. The amount of absorbed hydrogen is dependent on some factors such as for example the carburizing time and component dimensions. Hydrogen diffused in material can then cause hydrogen embrittlement and in some cases cause cracking under a static load. This hydrogen must therefore be re...

  4. Kinetics and mechanical study of plasma electrolytic carburizing for pure iron

    Science.gov (United States)

    Çavuşlu, F.; Usta, M.

    2011-02-01

    In this work, plasma electrolytic surface carburizing of pure iron in aqueous solution consisting of water, glycerin and NH4Cl was investigated. Surface carburizing was carried out in 20% glycerin solution treated at 750 °C, 800 °C, 900 °C and 950 °C temperatures for 5, 10 and 30 min. The formation of hard carbon-rich layer on the surface of pure iron was confirmed by XRD analysis. Metallographic and SEM studies revealed a rough and dense carburized layer on the surface of the pure iron. Experimental results showed that the thickness of the carburized layers changes with the time and temperature. The average thickness of the carburized layer ranged from 20 to 160 μm. The hardness of the carburized samples decreased with the distance from the surface to the interior of the test material. The average hardness values of the carburized layers on the substrate ranged 550-850 HV, while the hardness of the substrate ranged from 110 HV to 170 HV. The dominant phases formed on the pure iron were found to be a mixture of cementite (Fe3C), martensite (Fe + C) and austenite (FCC iron) confirmed by XRD. Wear resistance in all plasma electrolytic carburized samples is considerably improved in relation to the untreated specimen. After carburizing, surface roughness of the samples was increased. Friction coefficients were also increased because of high surface roughness.

  5. Nomograms to Determine the Controlling Factors in Vacuum-Carburizing Regimes

    Science.gov (United States)

    Semenov, M. Yu.

    2016-09-01

    A method based on computer evaluation of mechanical properties and a mathematical model of vacuum carburizing are used for creating two nomograms, i.e., ( 1 ) for determining the parameters that the carburized layers of gears of steel 16Kh3NVFMB-Sh must have to obtain the required service properties and ( 2 ) for determining the values that the factors in periodic carburizing regimes must have to ensure that the layers have the prescribed parameters. The nomograms are used to determine the factors for two gears that are to undergo vacuum carburizing.

  6. Low Temperature Surface Carburization of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K

    2007-12-07

    Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys

  7. Advances and directions of ion nitriding/carburizing

    Science.gov (United States)

    Spalvins, Talivaldis

    1989-01-01

    Ion nitriding and carburizing are plasma activated thermodynamic processes for the production of case hardened surface layers not only for ferrous materials, but also for an increasing number of nonferrous metals. When the treatment variables are properly controlled, the use of nitrogenous or carbonaceous glow discharge medium offers great flexibility in tailoring surface/near-surface properties independently of the bulk properties. The ion nitriding process has reached a high level of maturity and has gained wide industrial acceptance, while the more recently introduced ion carburizing process is rapidly gaining industrial acceptance. The current status of plasma mass transfer mechanisms into the surface regarding the formation of compound and diffusion layers in ion nitriding and carbon build-up ion carburizing is reviewed. In addition, the recent developments in design and construction of advanced equipment for obtaining optimized and controlled case/core properties is summarized. Also, new developments and trends such as duplex plasma treatments and alternatives to dc diode nitriding are highlighted.

  8. Cu-Precipitation Strengthening in Ultrahigh-Strength Carburizing Steels

    Science.gov (United States)

    Tiemens, Benjamin L.; Sachdev, Anil K.; Olson, Gregory B.

    2012-10-01

    Ultrahigh hardness levels greater than 700 VHN can be obtained in secondary hardening carburizing steels but depend on costly Co alloying additions to maximize hardness achieved through M2C-type carbide precipitation strengthening. This study aims to incorporate nanometer-scale bcc Cu precipitates to both provide strength as well as catalyze M2C nucleation in the absence of or with reduced Co. Cu additions of 1.0 and 3.7 wt pct were investigated, using a series of mechanistic models coupled with thermodynamic computational tools to derive final compositions. Thirty-pound experimental heats were cast of each designed alloy, samples of which were carburized and tempered to determine their hardness response. Characterization revealed the successful incorporation of Cu alloying additions into this family of steels, demonstrating a secondary hardening response even in the absence of Co. Matrix strength levels were close to those predicted by design models; however, all four alloys demonstrated a hardness deficit of approximately 200 VHN at the carburized surface, suggesting recalibration of the M2C precipitation strengthening model may be required in these alloys.

  9. Paraequilibrium Carburization of Duplex and Ferritic Stainless Steels

    Science.gov (United States)

    Michal, G. M.; Gu, X.; Jennings, W. D.; Kahn, H.; Ernst, F.; Heuer, A. H.

    2009-08-01

    AISI 301 and E-BRITE stainless steels were subjected to low-temperature (743 K) carburization experiments using a commercial technology developed for carburization of 316 austenitic stainless steels. The AISI 301 steel contained ~40 vol pct ferrite before carburization but had a fully austenitic hardened case, ~20- μm thick, and a surface carbon concentration of ~8 at. pct after treatment; this “colossal” paraequilibrium carbon supersaturation caused an increase in lattice parameter of ~3 pct. The E-BRITE also developed a hardened case, 12- to 18- μm thick, but underwent a more modest (~0.3 pct) increase in lattice parameter; the surface carbon concentration was ~10 at. pct. While the hardened case on the AISI 301 stainless steel appeared to be single-phase austenite, evidence for carbide formation was apparent in X-ray diffractometer (XRD) scans of the E-BRITE. Paraequilibrium phase diagrams were calculated for both AISI 301 and E-BRITE stainless steels using a CALPHAD compound energy-based interstitial solid solution model. In the low-temperature regime of interest, and based upon measured paraequilibrium carbon solubilities, more negative Cr-carbon interaction parameters for austenite than those in the current CALPHAD data base may be appropriate. A sensitivity analysis involving Cr-carbon interaction parameters for ferrite found a strong dependence of carbon solubility on relatively small changes in the magnitude of these parameters.

  10. The effects of energizer and carburizing temperature and time on mechanical properties of hardened big knives in the pack carburizing process

    Directory of Open Access Journals (Sweden)

    Narongsak Thammachot

    2016-10-01

    Full Text Available The purpose of this research is to study the effects of energizer and carburizing temperature and time on the mechanical properties of hardened big knives in the pack carburizing process. The mechanical properties of carburized and hardened big knives were compared to those of commercial hardened big knives made from leaf-spring steel that were forged, ground and quenched following the traditional forging processes. The experiment was conducted by forging big knives made of low carbon steel (grade AISI 1010. The first group of them was then pack-carburized using 10% by weight of calcium carbonate with 90% by weight of eucalyptus charcoal. The second group used 10% by weight of egg shell with 90% by weight of eucalyptus charcoal. The carburizing temperatures were 900, 950 and 1,000°C, with carburizing times of 30, 60 and 90 minutes followed by air cooling. The austenitizing temperature was 780°C with a holding time of 20 minutes, followed by quenching in water. Finally, the big knives were tempered at 180°C for 1 hour. Micro-Vickers hardness testing, impact testing and microstructure inspection were carried out. The results of this experiment show that the hardness of hardened big knives increased with an increase in the carburizing temperature and time. In contrast, the impact value of carburized steel decreased with an increase in the carburizing temperature and time. The hardness derived from using CaCO3 is slightly harder than that from using egg shell, however, the impact energy is higher when using egg shell, compared to using CaCO3.

  11. Research on Eddy Current Testing System of the Carburized Layer Depth of 20CrMnTi Steel

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiao-min; LI Na; WU Xin- wen; FANG Hua-bin

    2004-01-01

    In this paper the carbon distribution in the carburized layer of 20CrMnTi steel was studied. The relationship between the depth of a carburized layer and the surface carbon distribution was established. Eddy current testing system of the case depth of this carburized steel was built by using ANSYS software as second development platform.

  12. Low Temperature Surface Carburization of Stainless Steels

    Energy Technology Data Exchange (ETDEWEB)

    Collins, Sunniva R; Heuer, Arthur H; Sikka, Vinod K

    2007-12-07

    Low-temperature colossal supersaturation (LTCSS) is a novel surface hardening method for carburization of austenitic stainless steels (SS) without the precipitation of carbides. The formation of carbides is kinetically suppressed, enabling extremely high or colossal carbon supersaturation. As a result, surface carbon concentrations in excess of 12 at. % are routinely achieved. This treatment increases the surface hardness by a factor of four to five, improving resistance to wear, corrosion, and fatigue, with significant retained ductility. LTCSS is a diffusional surface hardening process that provides a uniform and conformal hardened gradient surface with no risk of delamination or peeling. The treatment retains the austenitic phase and is completely non-magnetic. In addition, because parts are treated at low temperature, they do not distort or change dimensions. During this treatment, carbon diffusion proceeds into the metal at temperatures that constrain substitutional diffusion or mobility between the metal alloy elements. Though immobilized and unable to assemble to form carbides, chromium and similar alloying elements nonetheless draw enormous amounts of carbon into their interstitial spaces. The carbon in the interstitial spaces of the alloy crystals makes the surface harder than ever achieved before by more conventional heat treating or diffusion process. The carbon solid solution manifests a Vickers hardness often exceeding 1000 HV (equivalent to 70 HRC). This project objective was to extend the LTCSS treatment to other austenitic alloys, and to quantify improvements in fatigue, corrosion, and wear resistance. Highlights from the research include the following: • Extension of the applicability of the LTCSS process to a broad range of austenitic and duplex grades of steels • Demonstration of LTCSS ability for a variety of different component shapes and sizes • Detailed microstructural characterization of LTCSS-treated samples of 316L and other alloys

  13. High temperature carburizing of a stainless steel with uranium carbide

    Energy Technology Data Exchange (ETDEWEB)

    Sar Latin-Small-Letter-Dotless-I kaya, Yueksel, E-mail: sakaya@science.ankara.edu.tr [Ankara University, Faculty of Science, Department of Chemistry, Tandogan, 06100 Ankara (Turkey); Oenal, Mueserref [Ankara University, Faculty of Science, Department of Chemistry, Tandogan, 06100 Ankara (Turkey)

    2012-11-25

    Graphical abstract: Temperature dependence of diffusion coefficient for carbon atoms in steel by carburizing with uranium carbide was found as: D = 2.6 Multiplication-Sign 10{sup -11} exp (-66753/RT) in m{sup 2} s{sup -1} microhardness measurements. Changes in thermodynamic quantities by formation of an activated complex with temperature were obtained as follows: {Delta}H{sup numbersign} = 66741-8.3T J mol{sup -1}, {Delta}C{sub p}{sup numbersign} = 8.3 J K{sup -1} mol{sup -1}, ln K{sup numbersign} = -66741/RT = (8.3/R)lnT-48.3, {Delta}G{sup numbersign} = 66741 + 8.3T lnT + 48.3RT J mol{sup -1}, and {Delta}S{sup numbersign} = -409.9-8.3 lnT in J K{sup -1} mol{sup -1}. Highlights: Black-Right-Pointing-Pointer Diffusion and activated complex theories were applied on the carburizing of steel. Black-Right-Pointing-Pointer Carburizing of steel was investigated by microhardness measurements. Black-Right-Pointing-Pointer Diffusion coefficient of carbon in the steel was determined. Black-Right-Pointing-Pointer Thermodynamic quantities by formation an activated complex were determined. - Abstract: Diffusion theory (DT) and activated complex theory (ACT) were applied to the carburizing process of austenitic stainless steel 1.4988 with uranium carbide by sodium bonding at 773, 873, 973 and 1073 K for 1000 h. Microhardness profiles of the carburized steel specimens were obtained. Diffusion coefficient (D) of carbon atoms into the steel were calculated for each temperature by using the microhardness values instead of the carbon concentrations in the approximate solution of the second Fick's equation. Arrhenius equation for the carburizing process was found as: D = 2.6 Multiplication-Sign 10{sup -11} exp (-66753/RT) in m{sup 2} s{sup -1}. Equilibrium constant (K{sup numbersign}) and enthalpy of activation ({Delta}H{sup numbersign}) for the formation of an activated complex calculated for each temperature from the Eyring equation using the diffusion coefficient instead of the

  14. Cyclic strength of steel 16Kh3NVFBM-Sh (VKS-5) after vacuum carburizing

    Science.gov (United States)

    Ryzhov, N. M.; Fakhurtdinov, R. S.; Smirnov, A. E.

    2010-07-01

    Cyclic strength of steel 16Kh3NVFMB-Sh is studied after vacuum and gas carburizing. It is shown that the fatigue resistance of the steel hardened by the method of vacuum carburizing is higher. The thickness of the layer and the concentration of carbon on the surface at which the cyclic endurance is the highest are determined.

  15. Optimization of the Process of Carburizing and Heat Treatment of Low-Carbon Martensitic Steels

    Science.gov (United States)

    Ivanov, A. S.; Greben'kov, S. K.; Bogdanova, M. V.

    2016-05-01

    Steel 24Kh2G2NMFB is studied after carburizing and different heat treatments. The hardness and microhardness of the surface layer and of the matrix are measured. The content of retained austenite is determined by the method of x-ray diffraction analysis. Heat treatment modes improving the structure of the surface layer after carburizing are suggested.

  16. Acetylene Flow Rate as a Crucial Parameter of Vacuum Carburizing Process of Modern Tool Steels

    Directory of Open Access Journals (Sweden)

    Rokicki P.

    2016-12-01

    Full Text Available Carburizing is one of the most popular and wide used thermo-chemical treatment methods of surface modification of tool steels. It is a process based on carbon diffusive enrichment of the surface material and is applied for elements that are supposed to present higher hardness and wear resistance sustaining core ductility. Typical elements submitted to carburizing process are gears, shafts, pins and bearing elements. In the last years, more and more popular, especially in highly advanced treatment procedures used in the aerospace industry is vacuum carburizing. It is a process based on chemical treatment of the surface in lower pressure, providing much higher uniformity of carburized layer, lower process cost and much lesser negative impact on environment to compare with conventional carburizing methods, as for example gas carburizing in Endo atmosphere. Unfortunately, aerospace industry requires much more detailed description of the phenomena linked to this process method and the literature background shows lack of tests that could confirm fulfilment of all needed requirements and to understand the process itself in much deeper meaning. In the presented paper, authors focused their research on acetylene flow impact on carburized layer characteristic. This is one of the most crucial parameters concerning homogeneity and uniformity of carburized layer properties. That is why, specific process methodology have been planned based on different acetylene flow values, and the surface layer of the steel gears have been investigated in meaning to impact on any possible change in potential properties of the final product.

  17. In Situ Observation for Abnormal Grain Coarsening in Vacuum-Carburizing Process

    Science.gov (United States)

    Yogo, Yasuhiro; Tanaka, Kouji

    2014-06-01

    An in situ observation method was developed to investigate abnormal grain coarsening which occurs around the surface of steel during the vacuum-carburizing process. In this method, diffusion of carbon atoms in the vacuum carburizing was simulated by a cementite and steel diffusion couple. Abnormal grain coarsening, which appeared around the cementite and steel interface, was observed by a confocal scanning laser microscope. With this method, it was observed that when holding time was 60 seconds, the temperature at which the abnormal grain coarsening appeared in a specimen was higher when carburized than the temperature when not carburized. On the contrary, when holding time was 120 seconds, the temperature at which the abnormal grain coarsening appeared in a specimen was 10 K to 20 K lower than that in a non-carburized specimen. The validity of the observed results was confirmed by the calculated NbC fraction using Nb solubility and measured carbon content.

  18. THE COMPARISON OF THE RESIDUAL STRESSES BETWEEN CARBURIZED AND ONLY QUENCHED STEELS

    Directory of Open Access Journals (Sweden)

    Osman ASİ

    2001-02-01

    Full Text Available In this study, the residual stresses developing in carburized and only quenched steel of SAE 8620 (21NiCrMo2 which is widely used as a carburized steel (shafts, gears etc. was investigated. Carburizing programs was carried out in gas atmosphere for 45 minute at 940 °C. X-ray analysis was used to determine residual stress in the microstructures of the only quenched and carburized specimens. The results of x-ray analysis have shown that while the carburized specimens have a residual compressive stress at the surface -551N/mm 2 , the only quenched specimens have a residual compressive stress at the surface -125 N/mm 2 .

  19. Effect of carburization on electrochemical corrosion behaviours of TiAl alloy

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Cuijiao [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Hunan University of Technology, Zhuzhou, Hunan 412000 (China); He, Yuehui, E-mail: yuehui@mail.csu.edu.cn [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Yang, Junsheng; Nan, Bo; Liu, Xinli [State Key Laboratory for Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China)

    2013-04-20

    Highlights: ► The functional complex ceramic phase Ti{sub 2}AlC was formed by pack carburizing. ► The anodic polarization curve of the carburized TiAl alloy shows a larger passivation interval (about 1.246 V). ► The polarization resistance of the carburized TiAl alloy is at least seventeen times higher, compared to the untreated TiAl alloy. ► The corroded surface of the carburized TiAl alloy was covered with passive film. -- Abstract: Electrochemical corrosion behaviours of the untreated and the carburized of Ti-46.5Al (mol %) alloy were investigated. X-ray diffractometry (XRD) and scanning electron microscopy (SEM) were applied to characterize the carburized layer. Potentiodynamic polarization curve, electrochemical impedance spectroscopy (EIS) and SEM morphology of the corroded surface were used to evaluate corrosion resistance of both carburized and untreated TiAl alloy in 1 mol/L HCl. The outer layer of the carburized TiAl alloy is a continuous Ti{sub 2}AlC scale. Polarization curve and electrochemical impedance spectroscopy (EIS) of the carburized TiAl alloy present a nobler corrosion potential, a more positive pitting potential and a higher polarization resistance, respectively, compared with the untreated sample. After anodic corrosion or immersion corrosion, a deposited layer can be observed on the surface of the carburized titanium aluminide alloy. By contrast, pitting and crevasse corrosion occur on the surface of the untreated TiAl alloy after anodic corrosion and some corrosion products and slight corrosion appear on the surface of the untreated TiAl alloy after immersion corrosion.

  20. On the genesis of molybdenum carbide phases during reduction-carburization reactions

    Energy Technology Data Exchange (ETDEWEB)

    Guil-Lopez, R., E-mail: rut.guil@icp.csic.es [Grupo de Energia y Quimica Sostenibles, ICP-CSIC, Marie Curie 2, Cantoblanco, 28049-Madrid (Spain); Nieto, E. [Grupo de Energia y Quimica Sostenibles, ICP-CSIC, Marie Curie 2, Cantoblanco, 28049-Madrid (Spain); Departamento de Tecnologia Quimica y Energetica, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933-Mostoles (Spain); Botas, J.A. [Departamento de Tecnologia Quimica y Energetica, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, 28933-Mostoles (Spain); Fierro, J.L.G., E-mail: jlgfierro@icp.csic.es [Grupo de Energia y Quimica Sostenibles, ICP-CSIC, Marie Curie 2, Cantoblanco, 28049-Madrid (Spain)

    2012-06-15

    Molybdenum carbide has been prepared according to the carbothermal reduction method. Carbon black substrate was used as C-source whereas a H{sub 2}-flow was the reducing agent. Two different H{sub 2} consumption steps were identified during the carburization treatment. The low temperature step is related to the reduction of Mo{sup 6+}-to-Mo{sup 4+}, the higher temperature process accounts for the deep reduction of Mo{sup 4+}-to-metal Mo{sup 0} and its subsequent reaction with C to form the Mo-carbide. The influences of the maximum carburization temperature, carburization time, gas hourly space velocity regarding Mo-loading, heating rate and temperature of Ar pre-treatment were analyzed. All these conditions are interrelated to each other. Thus, the carburization process ends at 700 Degree-Sign C when Mo-loading is 10 wt%, however Mo-loading higher than 10 wt% requires higher temperatures. Carburization temperatures up to 800 Degree-Sign C are needed to fulfill Mo-carbide formation with samples containing 50 wt% Mo. Nevertheless, Ar pre-treatment at 550 Degree-Sign C and slow heating rates favor the carburization, thus requiring lower carburization temperatures to reach the same carburization level. - Graphical Abstract: H{sub 2}-consumption profile (TPR) during the molybdenum carburization process, XRD patterns of the reduced Mo-samples after carburization and TEM-micrographs with two different enlargement of the samples with 5, 20 and 50 wt% Mo. Highlights: Black-Right-Pointing-Pointer Control of carburization variables: tailor the reduced/carbide Mo-phases (single/mixture). Black-Right-Pointing-Pointer Mo carburization in two stages: (1) Mo{sup 6+}-Mo{sup 4+}; (2) Mo{sup 4+}-Mo{sup 0} and, at once, MoC. Black-Right-Pointing-Pointer The carburization process is faster than Mo{sup 4+} reduction. Black-Right-Pointing-Pointer XPS probed: reduced Mo particles show core-shell structure. Black-Right-Pointing-Pointer Core: reduced Mo (Mo{sub 2}C, MoO{sub 2} and/or Mo

  1. Plutonium ion emission from carburized rhenium mass spectrometer filaments

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, J.M.; Robertson, D.M.

    1985-01-01

    Physicochemical processes important to the application of thermal emission mass spectrometry were identified and clarified. Effects of filament carbon concentration and temperature on plutonium ion emissions from a carburized rhenium filament were determined. Filament carbon concentration profoundly affected the appearance and duration of an ion signal. A useful ion signal was produced only when the carbon saturation temperature of the filament was exceeded, at which point first-order kinetics were either achieved or closely approached. This paper explains observed ion emission behavior in terms of pausible carbothermic reduction reactions and carbon diffusion processes that direct the course of those reactions. 31 references, 5 figures.

  2. Direct reduction of carburized pre-reduced pellets by microwave heating

    Institute of Scientific and Technical Information of China (English)

    胡兵; 黄柱成; 易凌云; 姜涛

    2014-01-01

    A new iron-making process using carburized pre-reduced iron ore pellets and microwave heating is investigated. The pre-reduced pellets, with a porous structure, and fine particles are carburized homogeneously at 400-650 °C in a CO atmosphere. The carburized carbon not only acts reaction as a reduction agent, but also absorbs microwave in the reduction process. Hence, the carburized pre-reduced pellets can be rapidly reduced by microwave heating. There are three procedures involved in the process, namely, gas-based pre-reduction, low-temperature carburization and deep reduction by microwave heating. Carburized pre-reduced iron ore pellets show a rapid temperature rise that is twice as fast as the results for pre-reduced pellets in the laboratory. This not only improves the efficiency of the microwave heating, but also accelerates the reduction of iron oxides. The temperature of the pre-reduced pellets rises to 1050 °C in 45 min when the carburization rate is 2.02%, and the metallization rate and compressive strength reach 94.24%and 1725 N/pellet, respectively.

  3. Effect of Rare Earths on Diffusion Coefficient and Transfer Coefficient of Carbon during Carburizing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The diffusion coefficient of carbon in surface layer of steel-20 rare earth carburized at 880 ℃ and 900 ℃ for 8 h was calculated by substituting the measured layer depths into the diffusion equation. The mathematical model of the transfer coefficient of carbon was deduced based on the kinetics of weight gain during gas carburizing. The calculated results show that the main reason why the gas carburizing process is accelerated is due to the obvious increase in the diffusion coefficient and transfer coefficient of carbon resulted from the addition of RE.

  4. On the Notch Effect in Low Temperature Carburized Stainless Steel under Fatigue

    Directory of Open Access Journals (Sweden)

    Minak G.

    2010-06-01

    Full Text Available The present paper describes the fatigue behaviour of carburized notched AISI 316 austenitic stainless steel specimens. Rotary four point bending fatigue tests have been performed using carburized smooth specimens with two different values of surface rugosity and notched specimen with two different stress concentration factors Kt, of 3.55 and 6.50 and the effects of carburizing on fatigue strength and notch sensitivity were discussed. Results show a general improvement of the fatigue life due to the treatment for all the series with an apparent notch sensitivity lower than one in the case of blunt notches due to secondary effects that were singled out.

  5. A Probabilistic Approach to Examine the Effect of Chemistry Variations on Distortion During Industrial Gas Carburizing

    Science.gov (United States)

    Sahay, Satyam S.; Deshmukh, Vinayak; El-Zein, Mohamad

    2013-07-01

    Industrial carburizing operations have been traditionally simulated for several decades by solving the diffusion equation. However, using this deterministic approach, it is difficult to capture batch-to-batch variations in the properties attributed to process and chemistry variations. In the current study, a probabilistic approach is used to capture the variations in process parameters and alloy chemistry. The advantage of this approach is illustrated through a case study on reduction in distortion variations as well as its absolute value during the carburizing operation. Finally, some of the opportunities and challenges in the carburizing simulation are discussed.

  6. On the Notch Effect in Low Temperature Carburized Stainless Steel under Fatigue

    Science.gov (United States)

    Minak, G.

    2010-06-01

    The present paper describes the fatigue behaviour of carburized notched AISI 316 austenitic stainless steel specimens. Rotary four point bending fatigue tests have been performed using carburized smooth specimens with two different values of surface rugosity and notched specimen with two different stress concentration factors Kt, of 3.55 and 6.50 and the effects of carburizing on fatigue strength and notch sensitivity were discussed. Results show a general improvement of the fatigue life due to the treatment for all the series with an apparent notch sensitivity lower than one in the case of blunt notches due to secondary effects that were singled out.

  7. Modeling of Carbon Concentration Profile Development During Both Atmosphere and Low Pressure Carburizing Processes

    Science.gov (United States)

    Wei, Y.; Zhang, L.; Sisson, R. D.

    2013-07-01

    Heat treaters need an effective simulation tool to predict the carburization performance of a variety of steels. The tool is needed to not only predict the carbon profile but also optimize the process in terms of the cycle time and the total cost. CarbToolhas been developed to meet these needs for gas and vacuum carburization. In this article, CarbToolpredictions were compared with industrial experimental results for three types of steels (AISI 8620, 5120, and 4320), heat treated by both gas and vacuum carburizing processes. Based on the agreement of model predictions and experimental results, it is found that CarbToolcould be used to predict the carbon concentration profile for a variety of alloys in both gas and vacuum carburizing processes.

  8. Structure-phase states of the nickel surface layers after electroexplosive carburizing

    Institute of Scientific and Technical Information of China (English)

    Budovskikh; E.; A.; Bagautdinov; A.; Y.; Ivanov; Yu.; F.; Martusevich; E.; V.; Gromov; V.; E.

    2005-01-01

    The layer by layer study of the structure-phase states of the nickel surface layer carburizing with use the phenomena of the electrical explosion has conducted by the method TEM of the fine foils.……

  9. Deformation and fatigue behaviors of carburized automotive gear steel and predictions

    Directory of Open Access Journals (Sweden)

    Bonglae Jo

    2016-07-01

    Full Text Available The fatigue behavior of carburized components such as automotive transmission gears is very complex due to hardness and microstructure difference, residual stresses and multi-axial stress states developed between the case and the core. In addition, automotive gears in service, commonly used in helical type, are actually subjected to complex stress conditions such as bending, torsion, and contact stress states. This study presents experimental and analytical results on deformation behavior of carburized steels, widely used in automotive gears, under cyclic stress conditions including axial and torsion loadings. Axial fatigue tests and rotating bending fatigue tests are also included. Predictions of cyclic deformation and fatigue behaviors of the carburized steel with two-layer model are compared with experimental results. The carburized steel investigated in this study exhibited cyclic softening under both axial loading and torsional loading. Predicted results with simple two-layer model for the cyclic deformation and fatigue behaviors were comparatively similar to the experimental data.

  10. Wettability Modification for Biosurface of Titanium Alloy by Means of Sequential Carburization

    Institute of Scientific and Technical Information of China (English)

    Yong Luo; Shirong Ge; Zhong-min Jin

    2009-01-01

    Microporous titanium carbide coating was successfully synthesized on medical grade titanium alloy by using sequential carburization. Changes in the surface morphology of titanium alloy occasioned by sequential carburization were characterized and the wettability characteristics were quantified. Furthermore, the dispersion forces were calculated and discussed. The results indicate that sequential carburization is an effective way to modify the wettability of titanium alloy. After the carburization the surface dispersion force of titanium alloy increased from 76.5 × 10-3 J·m-2 to 105.5 × 10-3 J·m-2, with an enhancement of 37.9 %. Meanwhile the contact angle of titanium alloy decreased from 83° to 71.5°, indicating a significant improvement of wettability, which is much closer to the optimal water contact angle for cell adhesion of 70°.

  11. Computational Evaluation of Cyclic Strength of Carburized Gears from Heat-Resistant Steels

    Science.gov (United States)

    Semenov, M. Yu.

    2014-11-01

    An advanced model for computing the fatigue bending strength of gears fabricated from a complexly alloyed heat-resistant steel 16Kh3NVFMB-Sh (VKS-5) subjected to vacuum carburizing in acetylene is suggested. The model matches experimental data satisfactorily and has been used to develop a mode for vacuum carburizing of gears from the heat-resistant steel to provide a high fatigue resistance.

  12. Surface properties and activation energy of superplastically carburized duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ahamad, Nor Wahida, E-mail: wahida_um@yahoo.com [Department of Mechanical and Materials Engineering, Faculty of Engineering, University Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Jauhari, Iswadi, E-mail: iswadi@um.edu.my [Department of Mechanical and Materials Engineering, Faculty of Engineering, University Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Azis, Sharidah Azuar Abdul, E-mail: sharidah_azuar@yahoo.com [Department of Mechanical and Materials Engineering, Faculty of Engineering, University Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia); Aziz, Nur Hafizah Abd, E-mail: phiza_aziz@yahoo.com [Department of Mechanical and Materials Engineering, Faculty of Engineering, University Malaya, Lembah Pantai, 50603 Kuala Lumpur (Malaysia)

    2010-08-01

    A new surface carburizing technique which combines superplastic phenomenon and carburizing process called superplastic carburizing (SPC) was introduced and compared with conventional carburizing (CC) process. Thermomechanically treated duplex stainless steel (DSS) with a fine grain microstructure that exhibits superplasticity was used as the superplastic material. SPC was carried out at temperatures of 1198-1248 K and a compression rate of 1 x 10{sup -4} s{sup -1} for various durations. Metallographic studies revealed that a carbon layer with a uniform, dense and smooth morphology formed on all carburized specimens. The case depth of the carbon layer was between 50.8 and 159.1 {mu}m. A remarkable increase in surface hardness was observed in the range 389.9-1129.0 HV. Activation energy for SPC was determined as 183.4 kJ mol{sup -1}, which is lower compare to CC process. The results indicate that SPC accelerates the diffusion of carbon atoms into the surface of DSS, thus increasing the thickness of the carburized layer and the surface hardness, at lower activation energy.

  13. Influence of vacuum carburizing treatment on fatigue crack growth characteristic in DSG2

    Directory of Open Access Journals (Sweden)

    K. Nambu

    2015-10-01

    Full Text Available The aim of this research is to clarify the influence of vacuum carburizing on the fatigue-crack progress characteristics of DSG2 steel. The test specimen tempering material (QT material and vacuum carburizing material (VC material has been used. The fatigue-crack progress was examined by subjecting the samples to four-point bending. The loading-capacity fixed experiment was done using a maximum load of Pmax = 4000– 7000 N. The ΔK fixed experiment was done using a load of ΔK = 18–36 MPa√m. The crack progress speed of VC material fell, after the high crack progress speed was shown, and after it showed the minimum, it showed the tendency to go up again. This is considered to be what is depended on the compressive residual stress given to the carburizing layer. From this, it is thinkable that there is a crack progress depression effect in a carburizing layer. In VC material, a carburizing layer has a crack progress depression effect from a plunger-helix bottom to about 2.6 mm, and it turned out that it is larger than an effective carburizing layer. Moreover, in each ΔK, it was shown that depression effect revelation differs and the crack progress process accompanying it was able to be shown typically.

  14. An investigation of rolling-sliding contact fatigue damage of carburized gear steels

    Science.gov (United States)

    Kramer, Patrick C.

    The goal of this study was to evaluate the differences in RSCF performance between vacuum and gas carburized steels as well as to investigate the evolution of damage (wear and microstructure changes) leading to pitting. Vacuum and gas carburizing was performed on two gear steels (4120 and 4320) at 1010°C. The carburized specimens were tested in the as-carburized condition using a RSCF machine designed and built at the Colorado School of Mines. The tests were conducted at 3.2 GPa nominal Hertzian contact stress, based on pure rolling, 100°C, and using a negative twenty percent slide ratio. Tests were conducted to pitting failure for each condition for a comparison of the average fatigue lives. Pure rolling tests were also conducted, and were suspended at the same number of cycles as the average RSCF life for a comparison of fatigue damage developed by RCF and RSCF. Incremental tests were suspended at 1,000, 10,000, 100,000, and 200,000 cycles for the vacuum carburized steels to evaluate the wear and damage developed during the initial cycles of RSCF testing and to relate the wear and damage to pitting resistance. Incremental damage was not investigated for gas carburizing due to the limited number of available specimens. The vacuum carburized samples showed a decreased pitting fatigue resistance over the gas carburized samples, possibly due to the presence of bainite in the vacuum carburized cases. Pitting was observed to initiate from surface micropitting and microcracking. A microstructural change induced by contact fatigue, butterflies, was shown to contribute to micropitting and microcracking. Incremental testing revealed that the formation of a microcrack preceded and was necessary for the formation of the butterfly features, and that the butterfly features developed between 10,000 and 100,000 cycles. The orientation and depth of butterfly formation was shown to be dependent upon the application of traction stresses from sliding. RSCF butterflies formed

  15. Isotope ratio measurements of pg-size plutonium samples using TIMS in combination with "multiple ion counting" and filament carburization

    Science.gov (United States)

    Jakopic, Rozle; Richter, Stephan; Kühn, Heinz; Benedik, Ljudmila; Pihlar, Boris; Aregbe, Yetunde

    2009-01-01

    A sample preparation procedure for isotopic measurements using thermal ionization mass spectrometry (TIMS) was developed which employs the technique of carburization of rhenium filaments. Carburized filaments were prepared in a special vacuum chamber in which the filaments were exposed to benzene vapour as a carbon supply and carburized electrothermally. To find the optimal conditions for the carburization and isotopic measurements using TIMS, the influence of various parameters such as benzene pressure, carburization current and the exposure time were tested. As a result, carburization of the filaments improved the overall efficiency by one order of magnitude. Additionally, a new "multi-dynamic" measurement technique was developed for Pu isotope ratio measurements using a "multiple ion counting" (MIC) system. This technique was combined with filament carburization and applied to the NBL-137 isotopic standard and samples of the NUSIMEP 5 inter-laboratory comparison campaign, which included certified plutonium materials at the ppt-level. The multi-dynamic measurement technique for plutonium, in combination with filament carburization, has been shown to significantly improve the precision and accuracy for isotopic analysis of environmental samples with low-levels of plutonium.

  16. Effect of Carburizing and Hardening Temperature on the Endurance of Forming Dies from Steel R6M5

    Science.gov (United States)

    Stepankin, I. N.; Ken'ko, V. M.; Boiko, A. A.

    2013-07-01

    Results of a study of the effect of carburizing of the forming surfaces of cold upset dies from high-speed steel R6M5 and of the hardening temperature on the structure and properties of the dies are presented. It is shown that the hardness and endurance of the carburized tools can be raised by hardening from lower temperatures.

  17. The sort of carburization and the quality of obtained cast iron

    Directory of Open Access Journals (Sweden)

    K. Janerka

    2008-12-01

    Full Text Available In the production of cast iron, the pig iron’s amount in charge material is more and more often limited, and replaced by steel scrap. That extorts the necessity of know-how the carburization and one is looking for carburizers, which ensure obtaining big carbon increment as quickly as possible with the high repeatability and the ones which ensure getting the adequate quality of cast iron. The object of presented research was definition of the influence of charge materials’ sort on the structure, course of solidification, and the effectiveness of process. The cast iron melts, which are presented below, are made only on the basis of steel scrap with portion of graphitoidal, coke and anthracite carburizers, which were added to the charge in solid. In the article one compared the carburizers in respect of their structure, chemical constitution and the effectiveness obtained during the carburization of liquid metal. The melting of cast iron, based on the special pig iron, was carried out as well. The course of melts, chemical constitution of obtained cast iron and its structure were presented. The comparison between quality distribution and the volume fraction of graphite in classes of size for the individual melts were achieved and the TDA curves were inserted.

  18. Study On The Effect Of Corrosion Behaviour Of Stainless Steel Before And After Carburizing Heat Treatment

    Science.gov (United States)

    Sulaiman, S. A.; Alias, S. K.; Ahmad, S.; Fauzi, M. H. Mohd; Ahmad, N. N.

    2016-11-01

    This study investigates the effect of corrosion behaviour of stainless steel before and after carburizing process. All samples were prepared based on the testing specification requirement and the chemical compositions of the stainless steel were obtained using spectrometer tester. Samples were then undergoing pack carburizing process by adding 50g of carbon powder as the carburizing agent. Then the samples were heated at 900 °C and 950 °C for 8 hours. To obtain corrosion rate, weight loss test was conducted and the samples were immersed in three different solutions which were distilled water, hydrochloric acid and sodium chloride. Hardness and density test were employed to measure the physical properties of the ASTM 304 stainless steel. The microstructures of all samples were observed using Olympus BX41M optical microscope. The resulting phases after each heat treatment were tested by x-ray diffraction (XRD) tester. The percentage of corrosion values, determined from this technique, showed fairly good agreement. Carburizing process produced a carburizing layer improved mechanical properties and corrosion resistance abilities

  19. Modeling Growth and Dissolution Kinetics of Grain-Boundary Cementite in Cyclic Carburizing

    Science.gov (United States)

    Ikehata, Hideaki; Tanaka, Kouji; Takamiya, Hiroyuki; Mizuno, Hiroyuki; Shimada, Takeyuki

    2013-08-01

    In vacuum carburizing of steels, short-time carburizing is usually followed by a diffusion period to eliminate the filmlike cementite ( θ GB ) grown on the austenite ( γ) grain boundary surface. In order to obtain the θ GB amount during the process, the conventional model estimates the amount of cementite ( θ) with the equilibrium fractions for local C contents within a framework of the finite difference method (FDM), which overestimates the amount of θ GB observed after several minutes of carburizing. In our newly developed model, a parabolic law is assumed for the growth of θ GB and the rate controlling process is considered to be Si diffusion rejected from θ under the isoactivity condition. In contrast, the rate constant for the dissolution of θ GB is considered to be controlled by Cr diffusion of θ. Both rate coefficients ( α) were validated using multicomponent diffusion simulation for the moving velocity of the γ/ θ interface. A one-dimensional (1-D) FDM program calculates an increment of θ GB for all grid points by the updated diffusivities and local equilibrium using coupled CALPHAD software. Predictions of the carbon (C) profile and volume fraction of cementite represent the experimental analysis much better than the existing models, especially for both short-time carburization and the cyclic procedure of carburization and diffusion processes.

  20. Influence of Al on the microstructure and carburization performance of a Ni-based alloy coating

    Energy Technology Data Exchange (ETDEWEB)

    Cangue, Feliciano Jose Ricardo, E-mail: fcangue@yahoo.com [Federal University of Parana, Centro Politecnico, s/n - Bairro Jardim das Americas, Curitiba, Parana, Cx P. 19011, CEP: 81531-990 (Brazil); D' Oliveira, Ana Sofia Climaco Monteiro, E-mail: sofmat@ufpr.br [Mechanical Engineering Department, Federal University of Parana, Centro Politecnico, s/n - Bairro Jardim das Americas, Curitiba, Parana, Cx P. 19011, CEP: 81531-990 (Brazil)

    2010-04-15

    Carburization is a degradation mechanism involving the diffusion of carbon into a metal alloy and its accumulation on the surface. Coke forms on the internal walls of crude oil refining equipment and adversely affects its efficiency and service life. In an attempt to enhance the service life of materials exposed to these aggressive environments, this work investigated the development of a protective coating to reduce the diffusion of carbon into the surfaces of components. Coatings were tailored by mixing the atomized Ni alloy (Hastealloy C) with 5 wt% and 15 wt% Al powders and deposited by Plasma Transferred Arc hardfacing. Pack carburizing was carried out at 650 deg. C and 850 deg. C for 6 h, and temperature stability was tested in an air furnace to evaluate the performance of the coatings. Characterization included measurement of Vickers microhardness profiles and microstructure analysis by optical and scanning electron microscopy and X-ray diffraction. The good weldability of the original Ni-based alloy was not altered by the presence of Al. Richer Al coatings developed ordered aluminide compounds in a Ni matrix and exhibited increased hardness and dilution. Exposure to temperatures of 650 deg. C and 850 deg. C in an air furnace and to a carburizing environment neither compromised coating hardness nor produced a carburizing layer, although carbides were identified at the top surface. Our results will be of benefit in the development of an alternative solution for the protection of components operating in carburizing environments.

  1. DECREASING HEAT TREATMENT COST OF SURFACE HARDENED MACHINE PARTS BY CASE CARBURIZATION

    Directory of Open Access Journals (Sweden)

    Ahmet Çetin CAN

    1997-03-01

    Full Text Available Machine parts are surface hardened to increase fatigue strength and wear resistance. Carburization is the most common surface hardening process in practice. In order to have optimum properties, a machine part must have certain hardness depth. To obtain required hardness depth, the parts must be kept in a carburizing medium at certain temperature for certain time. As the time and temperature is increased hardness depth increases. In practice, carburization temperature is about 930 °C. Machine parts are kept at this temperature for required time depending on required hardness depth. The increase of temperature reduces treatment time, considerably. But, heat treaters do not tend to use high temperatures due to the concern of distortion of parts, and deterioration of mechanical properties. In this study, the increase of temperature for reducing carburization time in salt bath, and consequently change of mechanical properties have been investigated using DIN C20 case carburization steel. As a result of experiments, it was found that mechanical properties were not effected negatively.

  2. Evaluation of the carburized surface of steels with Magnetic Barkhausen Noise; Avaliacao de superficie cementada de acos com efeito Barkhausen

    Energy Technology Data Exchange (ETDEWEB)

    Campos, M.F. de; Santos, R.; Silva, F.S. da; Ribeiro, S.B.; Lins, J.F.C., E-mail: mcampos@metal.eeimvr.uff.b [Universidade Federal Fluminense (PUVR/UFF), Volta Redonda, RJ (Brazil). Polo Universitario de Volta Redonda; Franco, F.A.; Padovese, L.R. [Universidade de Sao Paulo (EPUSP), SP (Brazil). Escola Politecnica

    2010-07-01

    Steels with different carbon content, 0.11%C and 0.48%C were submitted to a heat treatment for carburization in the surface. The samples were analyzed in the conditions: normalized, only carburized and carburized and quenched as received. The Magnetic Barkhausen Noise (MBN) was measured in all samples. A better understanding of the relation between microstructure and MBN is of large interest for nondestructive characterization. X-ray diffraction (XRD) has revealed large peak broadening for the samples carburized and quenched, which have martensite. This is due to the high density of dislocations and high internal stress in the martensite. It is also found that the MBN peaks are quite distinct for the samples with martensite, which present nanocrystalline structure. When martensite is present, domain rotation occurs more significantly, reducing the permeability and the MBN envelope signal intensity. MBN is a suitable method for non-destructive evaluation of the quality of the carburization process. (author)

  3. Numerical Simulation of Reaction-Diffusion during Carburization of HK40 Steel

    Institute of Scientific and Technical Information of China (English)

    Meili ZHU; Qiang XU; Junshan ZHANG

    2003-01-01

    Two types of carbides M23C6 and M7C3 precipitate orderly as carbon concentration in a high Cr-Ni austenitic steel increases during carburization process. The mathematical model that describes diffusion of carbon and the precipitation of M23C6 and M7C3 has been studied. A criterion to judge when the transformation of M23C6 to M7C3 is over and M7C3 precipitates directly has been given in simulated calculation. By applying the model, the carburization of HK40 steel has been calculated by means of finite difference computation techniques. The pack carburization tests for the HK40 steel have been carried out at 1273 K. The comparison between the experimental and the calculated results show acceptable agreement.

  4. Mathematical modeling and validation of the carburizing of low carbon steels

    Science.gov (United States)

    García Mariaca, A.; Cendales, E. D.; Chamarraví, O.

    2016-02-01

    This paper shows the mathematical modeling of heat and mass transfer in transient state of cylindrical bars of low carbon steel subjected to carburizing process. The model solution for the two phenomena was performed using a one-dimensional analysis in the radius direction, using the numerical method of finite differences; also a sensitivity analysis by varying the coefficient of convective heat transfer (h) is performed. The modeling results show that this carburization steel is strongly dependent on h. These results suggest that if it can increase the value of h in this kind of process could reduce the time of process for this heat treatment. Additionally, an experimental procedure was established by carburization of a steel AISI SAE 1010, which develops cementing solid phase and the specimen steel and micrographic hardness profiles obtained from samples of the specimen analysis was performed, to determine the penetration depth of the carbon and validate this result over the values obtained by the computer model.

  5. The advantages of Low Pressure Carburizing in the Heat Treatment Subcontracting Business

    Institute of Scientific and Technical Information of China (English)

    Guy PRUNEL; Bruno STAUDER

    2004-01-01

    Low Pressure Carburizing (LPC) was introduced in the 90's in the western Europe Heat Treatment business,mainly for in-house applications where it was especially appreciated for carburizing of transmission parts. However the success of the LPC units installed for gears carburizing in the automotive industry has hindered the development of the process in other fields - like subcontracting business -, where its advantages deserve to be enlightened.After a brief review of the principle of the process, the interest of its classical application to transmission parts is described,underlining peculiarly the reduction of the distortion observed when LPC is associated with high pressure gas quenching.Then the less-known advantages of the LPC process, like the high accuracy and reproducibility of the results, the modeling possibility and the simulation easiness, the case-depth uniformity and the full flexibility of the units are considered,showing how they can be beneficial to subcontracting business.

  6. Effect of Carburization on the Mechanical Properties of Biomedical Grade Titanium Alloys

    Institute of Scientific and Technical Information of China (English)

    Yong Luo; Haibo Jiang; Gang Cheng; Hongtao Liu

    2011-01-01

    Titanium cermets were successfully synthesized on the surface of biomedical grade titanium alloys by using sequential carburization method. The mechanical properties such as hardness, fracture toughness and plasticity were measured to estimate the potential application of titanium cermets. The results show that after carburization the surface hardness of titanium cermets was 778 HV, with a significant improvement of 128% compared with that of titanium alloys. In addition, the fracture toughness of titanium cermets was 21.5×106 Pa·m1/2, much higher than that of other ceramics. Furthermore, the analysis of the loading-unloading curve in the nanoindentation test also indicates that the plasticity of titanium cermet reached 32.1%, a relatively high value which illustrates the combination of the metal and ceramics properties. The results suggest that sequential carburization should be an efficient way to produce titanium cermets with hard surface, high toughness and plasticity.

  7. The Effect of the Quenching Method on the Deformations Size of Gear Wheels after Vacuum Carburizing

    Directory of Open Access Journals (Sweden)

    Dybowski K.

    2016-06-01

    Full Text Available This paper presents a comparison of the deformations and residual stresses in gear wheels after vacuum carburizing process with quenching in high-pressure nitrogen and oil. The comparison was made on a medium-sized gear wheels, made of AMS6265 (AISI 9310 steel. This steel is applied in the aerospace industry for gears. The study has provided grounds for an assessment of the effect of the method of quenching on the size of deformations. Compared to oil quenching, high-pressure gas quenching following vacuum carburizing resulted in more uniform and smaller deformations.

  8. A numerical model for vacuum carburization of an automotive gear ring

    Science.gov (United States)

    Kim, Dong-Wan; Cho, Yi-Gil; Cho, Hoon-Hwe; Kim, Sung-Hwan; Lee, Won-Beom; Lee, Myoung-Gyu; Han, Heung Nam

    2011-12-01

    A vacuum carburizing-heat treatment of an annulus gear ring is simulated via a carburized predictive finite element model that accounts for both heat transfer and carbon diffusion. Profiles of carbon concentration along the depth of the gear ring were calculated and are congruent with measured values, which were obtained by a glow discharge spectrometer (GDS). While sensitive to carbon content, rigorous observation of the microstructures in the gear ring after heat treatment was attempted by transmission electron microscopy (TEM). The finial various martensitic microstructures in several parts of the gear ring may be well explained on the basis of the calculated carbon concentration.

  9. Influence of vacuum carburizing treatment on fatigue crack growth characteristic in DSG2

    OpenAIRE

    K. Nambu; Egami, N.

    2015-01-01

    The aim of this research is to clarify the influence of vacuum carburizing on the fatigue-crack progress characteristics of DSG2 steel. The test specimen tempering material (QT material) and vacuum carburizing material (VC material) has been used. The fatigue-crack progress was examined by subjecting the samples to four-point bending. The loading-capacity fixed experiment was done using a maximum load of Pmax = 4000– 7000 N. The ΔK fixed experiment was done using a load of ΔK = 18...

  10. 圆锥从动齿轮的渗碳工艺探析%Explore and Analysis of Carburization Process for Driven Bevel Gear Carburizing

    Institute of Scientific and Technical Information of China (English)

    马录

    2011-01-01

    通过多次试验,解决了圆锥从动齿轮渗碳后淬火变形及二次压淬时出现的氧化脱碳问题,并提出了合理建议.%The problems of quenching deformation, oxidation and decarburization of driven bevel gear after carburizing and then the second pressure quenching were solved through several experiments, and the reasonable proposal was put forward.

  11. Carburization and heat treatment to cause carbide precipitation in gamma/gamma prime-delta eutectic alloys

    Science.gov (United States)

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

    1977-01-01

    In an attempt to improve their longitudinal shear strength, several directionally solidified eutectic alloy compositions with minor element modifications were pact, carburized, and heat treated to provide selective carbide precipitation at the cell and grain boundaries. The directionally solidified Ni-17.8 Nb-6Cr-2.5Al-3Ta (weight percent) alloy was selected for the shear strength evaluation because it showed the shallowest delta-denuded zone at the carburized surface. The carburization-carbide precipitation treatment, however, did not appear to improve the longitudinal shear strength of the alloy.

  12. Ni-WC composite coatings by carburizing electrodeposited amorphous and nanocrystalline Ni-W alloys

    Science.gov (United States)

    Latif, Saadia; Mehmood, Mazhar; Ahmad, Jamil; Aslam, Muhammad; Ahmed, Maqsood; Zhang, Zhi-dong

    2010-03-01

    In situ formation of tungsten carbide in the matrix of FCC nickel has been achieved by carburizing of the electrodeposited Ni-W alloy coatings. The size of the carbide particles ranges between 100 and 500 nm. The carbide phase is also present in the form of very small precipitates inside the nickel grains. The size of such precipitates is between 10 and 40 nm. The carburizing environment was created by introducing a flowing mixture of vaporized 95.5% alcohol (0.25 ml/min, liquid) and argon (0.5 L/min, gas) into the carburizing furnace. Supersaturated nature of electrodeposited amorphous and nanocrystalline alloys, in addition to high diffusivity, have been attributed for the formation of carbide phase in the deposits at a temperature range of 700-850 °C. The carbide-metal interface is clean and the composite coatings are compact. Hardness values up to about 1100 KHN are achieved. Hardness increases with tungsten content and carburizing temperature.

  13. About Reverted Austenite in Carburized Layers of Low-Carbon Martensitic Steels

    Science.gov (United States)

    Ivanov, A. S.; Bogdanova, M. V.; Vylezhnev, V. P.

    2015-05-01

    Processes of surface hardening in low-carbon martensitic steel 24Kh2G2NMFTB under carburizing and subsequent quenching from the intercritical temperature range are studied. Special features of formation of reverted austenite with high strength and stability are considered.

  14. Experimental Study on Vacuum Carburizing Process for Low-Carbon Alloy Steel

    Science.gov (United States)

    Wei, Shaopeng; Wang, Gang; Zhao, Xianhui; Zhang, Xiaopeng; Rong, Yiming

    2013-10-01

    As a low-carbon alloy steel, 20Cr2Ni4A steel has an excellent mechanical properties. It has been used for producing heavy-duty gears, which require good wear and fatigue resistance. The vacuum carburizing process can improve the quality of gears and extend the service life. In this article, a complete heat-treatment process for 20Cr2Ni4A, with carburizing, tempering, quenching and cryogenic steps involved, was proposed. A numerical method was employed to design the carburizing step. The carburized samples were characterized by analysis of carbon profile, surface-retained austenite content, microstructure, and hardness profile. A good microstructure was obtained with acicular-tempered martensite, less-retained austenite, fine granular-dispersed carbides, and was oxide free. The final surface hardness was 64.2HRC, and the case depth was 0.86 mm, which meet the requirements of products. The relationships among process, performance, and microstructure were investigated to understand the inner connection.

  15. Ni-WC composite coatings by carburizing electrodeposited amorphous and nanocrystalline Ni-W alloys

    Energy Technology Data Exchange (ETDEWEB)

    Latif, Saadia [National Centre for Nanotechnology, Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad 45650 (Pakistan); Mehmood, Mazhar, E-mail: mazhar@pieas.edu.pk [National Centre for Nanotechnology, Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad 45650 (Pakistan); Ahmad, Jamil; Aslam, Muhammad [National Centre for Nanotechnology, Department of Chemical and Materials Engineering, Pakistan Institute of Engineering and Applied Sciences (PIEAS), Nilore, Islamabad 45650 (Pakistan); Ahmed, Maqsood [Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan); Zhang Zhidong [Institute of Metals Research, Chinese Academy of Science, Shenyang (China)

    2010-03-01

    In situ formation of tungsten carbide in the matrix of FCC nickel has been achieved by carburizing of the electrodeposited Ni-W alloy coatings. The size of the carbide particles ranges between 100 and 500 nm. The carbide phase is also present in the form of very small precipitates inside the nickel grains. The size of such precipitates is between 10 and 40 nm. The carburizing environment was created by introducing a flowing mixture of vaporized 95.5% alcohol (0.25 ml/min, liquid) and argon (0.5 L/min, gas) into the carburizing furnace. Supersaturated nature of electrodeposited amorphous and nanocrystalline alloys, in addition to high diffusivity, have been attributed for the formation of carbide phase in the deposits at a temperature range of 700-850 deg. C. The carbide-metal interface is clean and the composite coatings are compact. Hardness values up to about 1100 KHN are achieved. Hardness increases with tungsten content and carburizing temperature.

  16. RESULTS OF CHARACTERIZATION TESTS OF THE SURFACES OF A COMMERCIALLY CARBURIZED AUSTENITIC STAINLESS STEEL

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, K

    2004-01-07

    A commercial surface carburization treatment that shows promise for hardening the surfaces of the stainless steel target vessel of the Spallation Neutron Source against cavitation erosion and pitting caused by the action of pulsed pressure waves in the liquid mercury target has been investigated. To verify promotional claims for the treatment and to uncover any factors that might be of concern for the integrity of a carburized target vessel, some characterization tests of the nature of the surface layers of carburized austenitic 316LN stainless steel were conducted. The findings support most of the claims. The carburized layer is about 35 {micro}m thick. Its indentation hardness is about five times larger than that of the substrate steel and declines rapidly with depth into the layer. The surface is distorted by the treatment, and the austenite lattice is enlarged. The corrosion resistance of the carburized layer in an acid medium is greater than that for untreated austenite. The layer is not brittle; it is plastically deformable and is quite resistant to cracking during straining. Contrary to the provider's assertations, the maximum carbon content of the layer is much less than 6-7 wt% carbon, and the carbon is not simply contained in supersaturated solid solution; some of it is present in a previously unreported iron carbide phase located at the very surface. Large variations were found in the thickness of the layer, and they signify that controls may be needed to ensure a uniform thickness for treatment of the SNS target vessel. Inclusion stringers and {delta}-ferrite phase embraced in the treated layer are less resistant to chemical attack than the treated austenite. From a cavitation pitting perspective under SNS bombardment, such non-austenitic phases may provide preferential sites for pitting. The shallow depth of the hardened layer will require use of protection measures to avoid mishandling damage to the layer during assembly and installation of a

  17. Mechanical and Metallurgical Evaluation of Carburized, Conventionally and Intensively Quenched Steels

    Science.gov (United States)

    Giordani, T.; Clarke, T. R.; Kwietniewski, C. E. F.; Aronov, M. A.; Kobasko, N. I.; Totten, G. E.

    2013-08-01

    Steels subjected to carburizing, quenching, and tempering are widely used for components that require hardness and superficial mechanical resistance together with good core toughness. Intensive quenching is a method that includes advantages including crack prevention, increased mechanical resistance, and improvement in fatigue performance when subjected to very fast (intensive) cooling. However, achieving these advantages requires the formation of sufficiently high surface compressive residual stresses and fine grains at the core of steel components. If the cooling rate is sufficiently high after intensive quenching, then low-hardenability, killed plain carbon steels may be used instead of higher-cost, low alloy steels because compressive residual stresses are formed at the surface of steel parts. The objective of this study was to compare between carburized non-killed AISI 1020 steel samples, which were not modified by Al that were subsequently conventionally and also intensively quenched to determine the effect of quenching on achieving the necessary formation of fine grain size. For comparison, carburized AISI 8620 steel test specimens were conventionally quenched. After quenching, all test specimens were characterized by metallurgical and mechanical analyses. The results of this study showed that when the two quenching methods were compared for carburized non-killed AISI 1020 steel, intensive quenching method was found to be superior with respect to mechanical and metallurgical properties. When comparing the different steels, it was found that intensively quenched, non-killed, AISI 1020 steel yielded grain sizes which were three times greater than those obtained with conventionally quenched, carburized AISI 8620 steel. Therefore, the benefits of intensive quenching were negated. These results show that plain carbon steels must be modified by Al to make fine grains if intensively quenched plain-carbon steel is to replace alloyed AISI 8620 steel.

  18. Enhanced wear and corrosion resistance of plasma electrolytic carburized layer on T8 carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie; Wang, Bin; Zhang, Yifan; Liu, Run [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xia, Yuan; Li, Guang [Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2016-03-01

    A hardening layer of 70 μm on T8 carbon steel was fabricated by plasma electrolytic carburizing (PEC) in glycerol solution at 380 V with 3 min treatment. The discharge process was characterized using optical emission spectroscopy (OES), and the electron temperature in plasma envelope was determined. Meanwhile, diffusion coefficient of carbon was calculated on the basis of carbon concentration profile. The tribological property of carburized steel under dry sliding against ZrO{sub 2} ball was measured by a ball-disc friction and wear tester. The corrosion behaviors were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). It was found that the carburized layer mainly contained α-Fe and Fe{sub 3}C phases with maximum hardness of 620 HV. The PEC treatment significantly decreased the friction coefficient from 0.4 to 0.1. The wear rate of PEC treated steel was about 5.86 × 10{sup −6} mm{sup 3}/N·m, which was less than 1/4 of T8 steel substrate. After PEC treatment, the wear and corrosion resistance of T8 steel were improved. Particularly, the pitting corrosion of steel substrate was obviously suppressed. - Highlights: • Electron temperature in plasma electrolytic carburizing process is determined. • Diffusion coefficient of carbon in PEC is higher than conventional carburizing. • Wear and corrosion resistance of T8 steel are both improved after PEC treatment. • Pitting corrosion of steel substrate is obviously suppressed by PEC treatment.

  19. Nanostructural Evolution of Hard Turning Layers in Carburized Steel

    Science.gov (United States)

    Bedekar, Vikram

    The mechanisms of failure for components subjected to contact fatigue are sensitive to the structure and properties of the material surface. Although, the bulk material properties are determined by the steel making, forming and the heat treatment; the near surface material properties are altered during final material removal processes such as hard turning or grinding. Therefore, the ability to optimize, modulate and predict the near surface properties during final metal removal operations would be extremely useful in the enhancement of service life of a component. Hard machining is known to induce severely deformed layers causing dramatic microstructural transformations. These transformations occur via grain refinement or thermal phenomena depending upon cutting conditions. The aim of this work is to engineer the near surface nanoscale structure and properties during hard turning by altering strain, strain rate, temperature and incoming microstructure. The near surface material transformations due to hard turning were studied on carburized SAE 8620 bearing steel. Variations in parent material microstructures were introduced by altering the retained austenite content. The strain, strain rate and temperature achieved during final metal cutting were altered by varying insert geometry, insert wear and cutting speed. The subsurface evolution was quantified by a series of advanced characterization techniques such as transmission electron microscopy (TEM), glancing angle X-ray diffraction (GAXRD), X-ray stress evaluation and nanoindentation which were coupled with numerical modeling. Results showed that the grain size of the nanocrystalline near surface microstructure can be effectively controlled by altering the insert geometry, insert wear, cutting speed and the incoming microstructure. It was also evident that the near surface retained austenite decreased at lower cutting speed indicating transformation due to plastic deformation, while it increased at higher cutting

  20. EFFECTS OF CARBURIZING AND NITRIDING PROCESSES ON THE COST AND QUALITY OF GEARS PRODUCED WITH AISI 4140 AND 8620 STEELS

    Directory of Open Access Journals (Sweden)

    Claudio José Leitão

    2012-09-01

    Full Text Available This study compares the effects of nitriding and carburizing processes applied to gears subjected to contact stresses below 1300 MPa. The manufacturing cost, as well the depth of hardened layer and the distortion produced by two processes are analyzed. AISI 4140 gears quenched, tempered, liquid and gas nitriding and AISI 8620 gears after liquid carburizing, quenching and tempering are analyzed. The dimensional control of the gears was carried out before and after heat and thermochemical treatments. It is concluded that liquid or gas nitriding processes are about 30% more economical than liquid carburizing an also they reduce the dimensional changes. By the other hand liquid carburizing achieves greater case depth. Liquid nitriding process presents the lowest cost, dimensional changes and case depth.

  1. A study of internal oxidation in carburized steels by glow discharge optical emission spectroscopy and scanning electron microscopy

    CERN Document Server

    An, X; Rainforth, W M; Chen, L

    2003-01-01

    The internal oxidation of Cr-Mn carburizing steel was studied. Internal oxidation was induced using a commercial carburizing process. Sputter erosion coupled with glow discharge optical emission spectroscopy (GDOES) was used to determine the depth profile elemental distribution within the internal oxidation layer (<10 mu m). In addition, scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS) studies were carried out on selected sputter eroded surfaces. Oxide type was identified primarily by transmission electron microscopy (TEM). The carburized surface was found to consist of a continuous oxide layer, followed by a complex internal oxidation layer, where Cr and Mn oxides were found to populate grain boundaries in a globular form in the near surface region. At greater depths (5-10 mu m), Si oxides formed as a grain boundary network. The internal oxides (mainly complex oxides) grew quickly during the initial stages of the carburizing process (2 h, 800 deg. C+3 h, 930 deg. C). G...

  2. Formation of carburized layer structure with reverted austenite on low-carbon martensitic steel 12Kh2G2NMFT

    Science.gov (United States)

    Ivanov, A. S.; Bogdanova, M. V.

    2013-03-01

    The structure of surface layer in low-carbon martensitic steel 12Kh2G2NMFT obtained by carburizing followed by high-temperature tempering and quenching from the intercritical temperature range is investigated.

  3. Evaluation of Process Capability in Gas Carburizing Process to Achieve Quality through Limit Design Concept

    Institute of Scientific and Technical Information of China (English)

    K. Palaniradja; N. Alagumurthi; V. Soundararajan

    2004-01-01

    Steel is the most important metallic material used in industry. This is because of the versatility of its engineering properties under different conditions. In one condition it can be very mild, soft and suitable for any forming operation. In another condition the same steel can be very hard and strong. This versatility is made possible by the different heat treatments that the steel can be subject to. One such treatment is Gas carburizing. This is the most widely used process for surface hardening of low carbon steels. In this method the surface composition of the steel changes by diffusion of carbon and or nitrogen and result in hard outer surface with good wear resistance properties. A striking feature of Gas Carburizing process is that in this process the original toughness and ductility remains unaffected even after heat treatment. 3% nickel chromium case hardened low carbon steels are widely used for critical automotive and machine applications such as rack and pinion, gears, camshaft, valve rocker shafts and axles which requires high fatigue resistance. Fatigue behaviour of case carburized parts depends to a great extent on the correct combination of Hardness Penetration Depth (HPD) and the magnitude of hardness at the surface and beneath the surface with low size and shape distortion. In order to reduce the manufacturing costs in terms of material consumption and elimination of the number of processing steps, the effect of Gas carburizing parameters on the fatigue behaviour should already be considered in the parameter design stage. Therefore it is of importance to optimize the gas carburizing process variables to attain quality products with respect to hardness and case depth. In the present paper, the evaluation of process capability was carried out through a Limit Design Concept called orthogonal array design of experiment. To optimize the process variables the influence of several parameters (Holding time,Carbon potential, Furnace temperature and Quench

  4. LOW PRESSURE CARBURIZING IN A LARGE-CHAMBER DEVICE FOR HIGH-PERFORMANCE AND PRECISION THERMAL TREATMENT OF PARTS OF MECHANICAL GEAR

    Directory of Open Access Journals (Sweden)

    Emilia Wołowiec-Korecka

    2017-03-01

    Full Text Available This paper presents the findings of research of a short-pulse low pressure carburizing technology developed for a new large-chamber furnace for high-performance and precision thermal treatment of parts of mechanical gear. Sections of the article discuss the novel constructions of the device in which parts being carburized flow in a stream, as well as the low-pressure carburizing experiment. The method has been found to yield uniform, even and repeatable carburized layers on typical gear used in automotive industry.

  5. The Influence of Method of Carburizing and Nitrocarburizing on the Microstructure and Properties of Tool Steels

    Institute of Scientific and Technical Information of China (English)

    Tomasz Babul; Natalia Kucharieva; Aleksander Nakonieczny; Jan Senatorski

    2004-01-01

    The paper presents the results of wear and metallography tests of tool steel grades: ASTM A681, Chl2M and Ch12FS per GOST, AMS 6437E i BS X46Cr13, all surface hardened by the Carbo process (carburizing) and by the NiCar process (nitrocarburizing). The thermo-chemical treatment was conducted in powder pack for a duration of 6 h (carburizing)and for 4 h in the case of nitrocarburizing. Factors investigated were: morphology, depth and microhardness of the cases obtained, their microstructure, as well as phase composition. Wear tests were conducted by the three cylinder-cone method.Wear velocity was 0.58 m/s, unit load was 50 MPa and 400Mpa, wear path was 3470 m. Oil SAE30 was applied at the rate of 30 drops per minute.

  6. Ablation behavior of monolayer and multilayer Ir coatings under carburizing and oxidizing oxyacetylene flames

    Science.gov (United States)

    Wu, Wangping; Jiang, Jinjin; Chen, Zhaofeng

    2016-06-01

    Iridium is one of the most promising candidates for protective barrier of refractory materials to endure high service temperature. The multilayer iridium coating was produced by a double glow plasma process on the polished tungsten carbide substrates, compared with monolayer. The ablation behaviors of the monolayer on the unpolished and polished substrates were investigated under carburizing and oxidizing oxyacetylene flames, respectively, at the same time the multilayer coating ablated under oxidizing flames. Multilayer coating was a polycrystalline phase with the preferential (220) orientation. Monolayer on the unpolished substrate had fine coarse grains and some small microcracks were present. Multilayer consisted of columnar grains with some voids between the grains boundaries. The formation of a WIr phase in the as-deposited multilayer was attributed to high deposition temperature. The monolayer could endure high temperature up to 1800 °C in carburizing flame. The substrates could be protected more effectively by multilayer than monolayer at 2000- 2200 °C in oxidizing flame.

  7. Development of Nitrogen-Hydrocarbon Atmospheric Carburizing and Process Control Methods

    Science.gov (United States)

    Wang, Xiaolan; Zurecki, Zbigniew; Sisson, Richard D.

    2013-07-01

    Atmospheric pressure carburizing and neutral carbon potential annealing in nitrogen containing small additions of hydrocarbon gases can offer cost and steel surface quality alternatives to the comparable, endothermic atmosphere, or vacuum operations. An experimental program was conducted for refining real-time process control methods in carburizing of AISI 8620 steel under N2-CH4, N2-C3H8 blends containing <5 vol.% of hydrocarbon gas at 900 and 930 °C. Multiple types of gas analyzers were used to monitor residual concentrations of H2, CO, CO2, H2O, O2, CH4, C3H8, and other hydrocarbons inside furnace. A modified shim stock technique was additionally evaluated for correlation with gas analysis and diffusional modeling using measured carbon mass flux values (g/cm2/s). Results of this evaluation work are presented.

  8. Modeling of numerical simulation and experimental verification for carburizing-nitriding quenching process

    Institute of Scientific and Technical Information of China (English)

    R. MUKAI; T. MATSUMOTO; JU Dong-ying; T. SUZUKI; H. SAITO; Y. ITO

    2006-01-01

    A model considering quantitative effects of diffused carbon and nitrogen gradients and kinetics of phase transformation is presented to examine metallo-thermo-mechanical behavior during carburized and nitrided quenching. Coupled simulation of diffusion,phase transformation and stress/strain provides the final distribution of carbon and nitrogen contents as well as residual stress and distortion. Effects of both transformation and lattice expansion induced by carbon and nitrogen absorption were introduced into calculating the evolution of the internal stress and strain. In order to verify the method and the results,the simulated distributions of carbon and nitrogen content and residual stress/strain of a ring model during carburized and nitrided quenching were compared with the measured data.

  9. Surface carburizing of Ti-6Al-4V alloy by laser melting

    Science.gov (United States)

    Saleh, A. F.; Abboud, J. H.; Benyounis, K. Y.

    2010-03-01

    Surface carburizing of a Ti-6Al-4V alloy using laser melting has been investigated experimentally, with the aim of increasing surface hardness and hence improving related properties such as wear and erosion resistance. The surface of the material was coated with graphite prior to laser irradiation. Carburizing was achieved by a laser alloying mechanism, which includes melting the substrate and dissolution of the graphite in the liquid state. Two different types of lasers were used: (i) a continuous wave CO 2 (CW CO 2) laser with a maximum power of 3 kW, and (ii) a pulsating Nd-YAG laser with a maximum power per pulse of 100 W. Optical microscopy, scanning electron microscopy, EDS-analysis, and X-ray diffraction were carried out to analyze the microstructure and identify phases of the carburized layers. The results show that the carburized layers produced by CW CO 2 and Nd-YAG lasers are macroscopically homogeneous and have gradient features. The microstructures consisted of TiC crystals in the matrix of α'-Ti. The TiC crystals are either in the form of particles or dendrites. The depths to which these layers extend ranged from about 0.2-0.5 mm, depending on the treatment parameters. The volume fraction of the dendrites was found to decrease with increasing laser power or increasing traverse speed. Microhardness has been found to be directly related to the volume fraction and the size of the TiC phase. It increased to a value ranging from 500 to 800 Hv as compared to 350 Hv for the as-received substrate.

  10. Characteristic Features of Nanoscale Сarbide Inclusions Nucleation and Growth When Carburizing Steels

    Directory of Open Access Journals (Sweden)

    L.I. Roslyakova

    1990-01-01

    Full Text Available Thermodynamic calculations of the free energy of the formation of cementite type nanoscale carbides in supersaturated austenite alloyed with chromium and manganese are presented. It is shown that when carburizing steel, chromium stabilizing cementite facilitates its separation, in the form of dispersed inclusions. Manganese stabilizes cementite much weaker than chromium, though facilitates the growth of carbide inclusions due to the formation of the intermediate ε-phase at a reduced carbon content.

  11. RJJ-75-9TG井式气体渗碳炉工艺渗碳软件的应用%RJJ-75-9TG pit gas carburizing furnace carburizing process software applications

    Institute of Scientific and Technical Information of China (English)

    王海成

    2014-01-01

    选用北京培特公司技术开发的HT8002AC 井式炉渗碳/碳氮共渗工艺过程计算机控制系统,技术改进2台RJJ-75-9TG 井式气体渗碳炉的渗碳控制系统,实现计算机对整个工艺渗碳全过程的模拟控制,并时刻跟踪和修正现场设备参数的动态变化。提升了渗碳件的产品质量,确保汉德公司两到三年之内的自制件,能够达到国际出口标准。%Selection of Beijing tissue culture technology development company HT8002AC pit furnace carburizing / carbonitriding process computer control systems, technical improvements 2 RJJ-75-9TG pit gas carburizing carburizing furnace control system, the entire computer analog control the whole process of carburizing process and time tracking and dynamic correction field device parameters. Improve product quality carburizing, ensuring homemade pieces Hande within two to three years to reach the international export standards.

  12. Optimization of Modes of Vacuum Carburizing of Gears from Heat-Resistant Steel VKS-7 on the Basis of Computational Design

    Science.gov (United States)

    Semenov, M. Yu.; Smirnov, A. E.; Fakhurtdinov, R. S.; Ospennikova, O. G.; Gromov, V. I.

    2015-05-01

    Mathematical simulation is used to develop modes of vacuum carburizing providing the specified level of operating properties in high-load gears from steel VKS-7. The computed values of the operating properties are compared to experimental data obtained by testing check pieces subjected to vacuum carburizing by the modes developed.

  13. Effect of carburizing temperature and time on mechanical properties of AISI/SAE 1020 steel using carbonized palm kernel shell

    Directory of Open Access Journals (Sweden)

    Olanike M. OLUWAFEMI

    2015-12-01

    Full Text Available The effects of varied carburizing temperatures and holding time on the mechanical properties of AISI/SAE1020 steel have been investigated. Standard test samples prepared from the steel sample were subjected to pack hardening process using carbonized palm kernel shell as a carburizer at 800°, 850°, 900° and 950°C and held for 60, 90 and 120 minutes, quenched in oil and temper at 500°C for 60 minutes. After pack hardening process, the test samples were subjected to tensile, impact and hardness tests. and from the data obtained Ultimate tensile strength (UTS and impact strength were calculated, the case and the core hardness of the carburized samples were taken and optical microscope was also used to observe the micro structural features of the case hardened, quenched and tempered samples. It was observed that at 800°, 850° and 900°C, the UTS and the micro hardness initially reduces to minimum and then increased as the carburizing temperature increased, but at 950°C, it was observed that the UTS increases with increase in holding time. It was concluded that the optimum combination of mechanical properties is achieved at the carburizing temperature of 950°C soaked for 120 minutes followed by oil quenching and tempered at 500°C for 60 minutes.

  14. Damage prediction of HP40Nb steel with coupled creep and carburization based on the continuum damage mechanics

    Institute of Scientific and Technical Information of China (English)

    Limin SHEN; Jianming GONG; Yong JIANG; Luyang GENG

    2012-01-01

    HP40Nb steel,used as a candidate material for ethylene cracking furnace tube,suffers creep and carburization damage from the complex environment of high temperature,high carbon potential and low oxygen partial pressure,and they lead to failure of the furnace tubes ahead of designed life.In order to investigate damage evolution under the complex condition,coupled creep damage and carburization damage constitutive equations were developed according to continuum damage mechanics theory.Based on the finite element ABAQUS code,user subroutines were developed for analyzing damage evolution of ethylene furnace tube under the action of coupled creepcarburization.The results show that carburization accelerates the damage process dramatically,damage value reaches the critical value along the inner surface after serving for 75,000 h under the action of creep-carburization,meanwhile the damage value is only 0.53 along the outer surface after operating the same time under the action of creep alone,which means that microcracks are generated along the inner surface under the action of coupled creep-carburization,fracture begins along the outer surface of tube under the action of creep alone.

  15. Influence of Surface Carburization of Machinable Ceramics on Its Pulsed Flashover Characteristics in Vacuum%Influence of Surface Carburization of Machinable Ceramics on Its Pulsed Flashover Characteristics in Vacuum

    Institute of Scientific and Technical Information of China (English)

    郑楠; 黄学增; 穆海宝; 张冠军

    2011-01-01

    For pulsed power devices, surface flashover phenomena across solid insulators greatly restrict their overall performance. In recent decades, much attention has been paid on enhancing the surface electric withstanding strength of insulators, and it is found that surface treatment of material is useful to improve the surface flashover voltage. The carburization treatment is employed to modify the surface components of newly-developed machinable ceramics (MC) materials. A series of MC samples with different glucose solution concentration (0%, 10%, 20%, 30% and 40%) are prepared by chemical reactions for surface carburization modification, and their surface fiashover characteristics are investigated under pulsed voltage in vacuum. It is found that the surface carburization treatment greatly modifies the surface resistivity of MCs and hence the flashover behaviors. Based on the reduction of surface resistivity and the secondary electron emission avalanche (SEEA) theory, the adjustment of flashover withstanding ability can be reasonably explained.

  16. 气体渗碳CAD软件的试验验证%Experimental Verification of CAD Software for Gas Carburizing

    Institute of Scientific and Technical Information of China (English)

    孙炳超; 张戈; 钱初钧; 田禾; 沙云卿

    2001-01-01

    According to technical requirement of 1.2mm and 1.4mm carburizing depth, steel 20CrMnTi and 20CrMo test pieces were carburized in Unicase furnace with a gas carburizing dynamic control CAD system.The results show that this system has a powerful function and control exactly,the deviation of surface carbon concentration is less than 0.05%(weight),carbon concentration gradient curve in carburized layer is smooth and shows “S” shape,the deviation of carburizing depth is less than 0.05mm when the carburizing depth is 1.2mm or 1.4mm.The experimental results are fit well with that designed by software system.%用20CrMnTi和20CrMo钢制的试样,根据渗碳层深度分别为1.2mm和1.4mm的齿轮的技术要求,在装备有气体渗碳动态碳势控制CAD软件的渗碳炉上分别进行了试验,对模拟结果进行了验证,证实了该软件功能强劲、控制准确。其表面碳浓度(质量分数)偏差<0.05%;渗层内的碳浓度梯度曲线平滑,呈“S”型平台分布;渗层深度为1.2mm和1.4mm时,渗层深度的偏差<0.05mm。用该软件设计的渗碳工艺与实际检测结果能很好地吻合。

  17. Control of heat-resistant steel carburized layer structure. Part I

    Science.gov (United States)

    Semenov, M. Yu.

    2013-09-01

    A physical model of carbide formation with vacuum carburizing is developed with the aim of controlling complexly-alloyed steel diffusion layer structure, taking account of excess phase formation of both the cementite type, and special carbides. A mathematical model is developed on the basis of the physical model adopted, adequate for experimental results. Analysis of calculated results is used as a basis for demonstrating the effect on carbide formation of alloying with chromium and strong carbide-forming elements, and also production factors.

  18. Modelling of the carburizing and quenching process applied to caterpillar track bushings

    Science.gov (United States)

    Ferro, P.; Bonollo, F.

    2014-03-01

    The carburizing-quenching process applied to caterpillar track bushings was studied by means of experimental and numerical analyses. The numerical model was developed on the basis of the real cycle. The purpose of this work is to predict the carbon profiles, microstructural phase changes, hardness and residual stress that occur during quenching using finite element techniques. Good agreement was obtained between the experimental and numerical results in terms of carbon diffusion and hardness profiles. The Sysweld® numerical code was used to perform the simulations.

  19. Élaboration de nanostructures à une dimension à base de carbure de silicium

    OpenAIRE

    Ollivier, Maelig

    2013-01-01

    Le carbure de silicium est pressenti comme un matériau prometteur dans plusieurs domaines de l’électronique tels que la nano-électronique, l’électronique de puissance ou les capteurs travaillant en milieux hostiles (hautes températures, milieux corrosifs, milieux biologiques) du fait de ses propriétés physicochimiques supérieures à celles du silicium, notamment. Cependant, parmi les différentes méthodes d’élaboration par voie descendante ou ascendante permettant de fabriquer des nano-objets à...

  20. Catalytic Effect of Cerium Oxide on Carburization of Steel%氧化铈在钢表面气相渗碳时的催化作用

    Institute of Scientific and Technical Information of China (English)

    袁泽喜; 谭平; 余宗森; 徐庭栋

    2001-01-01

    Comparing the kinetics of gas carburization of steel 20 with the carburization agent containing cerium oxide or without it,it is found that cerium oxide in carburant can accelerate carburizing process greatly,which almost has the same effect at 850℃ and 910℃.This effect is accomplished by catalyzing mechanism of cerium oxide.RE in steel can also accelerate carburizing process,but its effect is less than RE in carburant. RE in steel can improve the catalysis of RE in carburant.%在20钢气相渗碳时对比了渗剂中加入CeO2或不加CeO2时的渗碳动力学,发现在渗剂中加入CeO2可以显著加快渗碳速率。稀土催渗剂的效果在850℃和910℃基本相同。认为CeO2加速渗碳的机制是催化。冶炼时在钢中加入的稀土对渗碳也起加速作用,但作用小于渗剂中的稀土。它还可以增强渗剂中稀土的催渗作用。

  1. 20CrMnMo钢稀土渗碳研究%Study on RE Carburizing of 20CrMnMo Steel

    Institute of Scientific and Technical Information of China (English)

    徐建军; 杜晓东

    2012-01-01

    RE carburization was carried out on 20CrMnMo steel. The carburizing kinetics of carburizing depth was dealed with, the microstructure of the carburized layer was observed, the hardness and abrasion resistance of the carburized layer were examined. The results show that a large amount of dispersed granular carbides precipitated in the carburized layer of 20CrMnMo steel RE carburized. The microstructure of surface layer after directly quenching consists of acicular martensite, fine granular carbides and a little residual austenite. The test results showed 10 persent improvement in hardness, 32 persent improvement in abrasion resistance,The touching fatigue life is sharply improved too.%采用稀土渗碳工艺对20CrMnMo钢进行渗碳处理,研究了渗层增厚的动力学、渗碳层组织和性能.结果表明:稀土渗碳层中沉淀析出了大量弥散分布的粒状碳化物,淬火后表层组织为针状马氏体、大量细小颗粒碳化物、少量残余奥氏体.渗碳层的硬度与传统工艺相比提高了10%,耐磨性提高了32%,接触疲劳寿命也有大幅提高.

  2. Analysis on microstructure of carburized layer in cast-iron molten bath carburized 20 steel%20钢铸铁浴渗碳渗层组织的分析

    Institute of Scientific and Technical Information of China (English)

    刘建华; 湛岩; 张瑞军; 于升学; 杨雪梅

    2001-01-01

    The microstructure of carburized layer in 20 steel cast-iron molten bath carburized at different temperature and time was studied in the paper.The research results show that the microstructure of carburized layer which is at 130~150μm from the surface is cementite+pearlite+ferrite,when specimen immevsed for 30s in 1270℃;the micvostruchre of carburized layer which is at 0~120μm from the surface is cementite+pearlite,and bar carbides is obtained in the base.%本文探讨了20钢在铸铁浴中经不同温度及时间渗碳的渗层组织。结果表明,试样在1270℃的铸铁浴中保留30秒,距表面130~150μm处,其渗层组织为渗碳体+珠光体+铁素体;试样在1300℃的铸铁浴中保留30秒,距表面0~120μm处,其渗层组织为渗碳体+珠光体,且在基体上形成棒条状的碳化物。

  3. 低碳钢固体渗碳的实验与研究%Experiment and Research on Solid-carburizing for Low Carbon Steel

    Institute of Scientific and Technical Information of China (English)

    廖西平

    2012-01-01

    The experiment of solid-carburizing process on 20 steel and 20CrMoV steel has been fully developed, which includes preparatory heat-treatment, carburizing craft, metallographic structure, the final heat- treatment, etc. This experiment analyzed the factors of carburizing coating and hardness, and the basic law and technology of solid- carburizing process have been worked out. The experiment has proved that solid- carburizing craft has several advantages such as simple process, easily to operate and control, low cost, and without special devices. The solid- carburizing product completely meets conventional requirement. However, solid-carburizing process has its disadvantages such as thin carburizing coating and too long total operating time, thus solid- carburizing only fits for the production of single-piece on small scale.%对20、20CrMoV钢的固体渗碳进行了较全面的实验及研究,包括钢的预备热处理、渗碳工艺、金相组织、最终热处理等;分析了渗碳层、硬度的影响因素,并总结摸索出固体渗碳的基本规律和工艺技术;实验证明:固体渗碳工艺简单、操作简单、成本低廉,不需要专门设备;渗碳件在性能上完全能够达到常规渗碳的要求,但固体渗碳的渗碳层偏薄,时间较长,只能适应单件、小批量的生产。

  4. Green fuels, growth engines after petroleum; Les carburants verts, moteurs de la croissance apres le petrole

    Energy Technology Data Exchange (ETDEWEB)

    Mili, Dino

    2010-09-15

    The contribution of the new fuels to a greener environment is important and immediate. Thanks to clean novel technologies and to commercial plant projects in development, companies like Enerkem contribute to satisfy increasing global demand for clean energy. They stimulate local economies by creating jobs in an industry that offers real growth potential. Green fuels will gradually allow us to let go of non sustainable energy sources like oil to adopt a way of life based on sustainable development. They will also allow a shift towards a green economy. [French] La contribution des nouveaux carburants a un environnement plus vert est importante et immediate. Grace a des technologies propres novatrices et a des projets d'sines commerciales en developpement, des entreprises comme Enerkem contribuent a satisfaire a la demande mondiale croissante en energie propre. Elles stimulent les economies locales par la creation d'emplois dans une industrie qui offre un veritable potentiel de croissance. Les carburants verts permettront graduellement de nous affranchir des sources d'energie non renouvelables comme le petrole pour adopter un mode de vie base sur le developpement durable. Ils permettront aussi un virage vers une economie verte.

  5. Boronization and Carburization of Superplastic Stainless Steel and Titanium-Based Alloys

    Directory of Open Access Journals (Sweden)

    Masafumi Matsushita

    2011-07-01

    Full Text Available Bronization and carburization of fine-grain superplastic stainless steel is reviewed, and new experimental results for fine grain Ti88.5Al4.5V3Fe2Mo2 are reported. In superplastic duplex stainless steel, the diffusion of carbon and boron is faster than in non-superplastic duplex stainless steel. Further, diffusion is activated by uniaxial compressive stress. Moreover, non-superplastic duplex stainless steel shows typical grain boundary diffusion; however, inner grain diffusion is confirmed in superplastic stainless steel. The presence of Fe and Cr carbides or borides is confirmed by X-ray diffraction, which indicates that the diffused carbon and boron react with the Fe and Cr in superplastic stainless steel. The Vickers hardness of the carburized and boronized layers is similar to that achieved with other surface treatments such as electro-deposition. Diffusion of boron into the superplastic Ti88.5Al4.5V3Fe2Mo2 alloy was investigated. The hardness of the surface exposed to boron powder can be increased by annealing above the superplastic temperature. However, the Vickers hardness is lower than that of Ti boride.

  6. Analyses of quenching process during turn-off of plasma electrolytic carburizing on carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Jie; Liu, Run [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Xue, Wenbin, E-mail: xuewb@bnu.edu.cn [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China); Wang, Bin; Jin, Xiaoyue; Du, Jiancheng [Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of Nuclear Science and Technology, Beijing Normal University, Beijing 100875 (China); Beijing Radiation Center, Beijing 100875 (China)

    2014-10-15

    Highlights: • Cooling rate of carburized steel at the end of PEC treatment is measured. • The quench hardening in the fast or slow turn-off mode hardly takes place. • Decrease of the surface roughness during slow turn-off process is found. • A slow turn-off mode is recommended to replace the conventional turn-off mode. - Abstract: Plasma electrolytic carburizing (PEC) under different turn-off modes was employed to fabricate a hardening layer on carbon steel in glycerol solution without stirring at 380 V for 3 min. The quenching process in fast turn-off mode or slow turn-off mode of power supply was discussed. The temperature in the interior of steel and electron temperature in plasma discharge envelope during the quenching process were evaluated. It was found that the cooling rates of PEC samples in both turn-off modes were below 20 °C/s, because the vapor film boiling around the steel sample reduced the cooling rate greatly in terms of Leidenfrost effect. Thus the quench hardening hardly took place, though the slow turn-off mode slightly decreased the surface roughness of PEC steel. At the end of PEC treatment, the fast turn-off mode used widely at present cannot enhance the surface hardness by quench hardening, and the slow turn-off mode was recommended in order to protect the electronic devices against a large current surge.

  7. Analysis of Hardened Depth Variability, Process Potential, and Measurement Error in Case Carburized Components

    Science.gov (United States)

    Rowan, Olga K.; Keil, Gary D.; Clements, Tom E.

    2014-12-01

    Hardened depth (effective case depth) measurement is one of the most commonly used methods for carburizing performance evaluation. Variation in direct hardened depth measurements is routinely assumed to represent the heat treat process variation without properly correcting for the large uncertainty frequently observed in industrial laboratory measurements. These measurement uncertainties may also invalidate application of statistical control requirements on hardened depth. Gage R&R studies were conducted at three different laboratories on shallow and deep case carburized components. The primary objectives were to understand the magnitude of the measurement uncertainty and heat treat process variability, and to evaluate practical applicability of statistical control methods to metallurgical quality assessment. It was found that ~75% of the overall hardened depth variation is attributed to the measurement error resulting from the accuracy limitation of microhardness equipment and the linear interpolation technique. The measurement error was found to be proportional to the hardened depth magnitude and may reach ~0.2 mm uncertainty at 1.3 mm nominal depth and ~0.8 mm uncertainty at 3.2mm depth. A case study was discussed to explain a methodology for analyzing a large body of hardened depth information, determination of the measurement error, and calculation of the true heat treat process variation.

  8. Formation of nanocrystalline layers by surface severe plastic deformation and pulsed plasma electrolytic carburizing.

    Science.gov (United States)

    Aliofkhazraei, M; Rouhaghdam, A Sabour

    2010-07-01

    Surfaces of various kinds of metallic materials spheres were treated by nanocrystalline surface severe plastic deformation and then pulsed nanocrystalline plasma electrolytic carburizing to study nanocrystalline substrate effect on formation and nano-hardness of hard nanocrystalline layer. The surface layers of the metallic materials developed by the nanocrystalline surface severe plastic deformation were characterized by means of high resolution scanning electron microscope. Nearly equiaxed nanocrystals with grain sizes ranging from 15 to 90 nm were observed in the near surface regions of all metallic materials, which are low carbon steel and commercially pure titanium. The effect of substrate nanocrystallization on growth kinetics and hardness of formed nanocrystalline carbide layer was studied with the means of figure analysis and nanohardness tests. Figure analysis show the length to diameter ratio and distribution curve of nanocrystals and it has been found that the achieved properties of hard layer (growth rate, nano-hardness, nanostructure...) are related to these factors. It was also clarified that these techniques and surface nanocrystallization can be easily achieved in most of metallic materials. Results indicate that the resultant hardened carburized layers exhibited excellent hardness profile. Investigation of the layer characteristics showed strong dependence followed from the treatment experimental parameters as well as the shape of nanocrystals.

  9. Development of a carburizing and quenching simulation tool: numerical simulations of rings and gears

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, C.; Godlman, P.; Rangaswamy, P. [and others

    1996-10-01

    The ability to accurately calculate temperatures, stresses and metallurgical transformations in a single calculation or in a sequence of calculations is the key to prediction of distortion, residual stress and phase distribution in quench hardened automotive parts. Successful predictions in turn rely on the adequacy of the input data to the calculational procedure. These data include mechanical and thermal properties of the alloy phases over the range of temperature and strain rates experienced during the heat treat process, the mathematical description of the transformation kinetics, and the accuracy of the heat transfer boundary conditions. In this presentation we describe a calculational procedure using the ABAQUS{sup (1)} finite element code that simulates a carburizing and quench heat treat cycle for automotive gears. The calculational procedure features a numerically efficient 2-phase constitutive model, developed as part of the NCMS-Heat Treatment Distortion Prediction program, to represent transformational plasticity effects for the austenite/martensite Deformation together with refined finite element meshes to capture the steep gradients in stress and composition near the gear surfaces. The calculational procedure is illustrated on carburizing and quenching of a thick ring and comparison of model predictions for distortion, phase distribution, and residual stress with experimental measurements are discussed. Included in this model study is an investigation of the sensitivity of the predictions to mesh refinement.

  10. Contribution to the study of gaseous Carburization of Uranium; Contribucion al estudio de la Carburacion gaesosa del uranio

    Energy Technology Data Exchange (ETDEWEB)

    Esteban Hernandez, J. A.; Jimenez Moreno, J. M.; Villota Ruiz, P. de

    1966-07-01

    Thermal decomposition of uranium hydride powder obtained by hydrogenation of uranium turnings is studied on the first part of this paper. Carburization of the uranium hydride or metallic uranium powder with methane is studied in the second part. A method of uranium monocarbide fabrication under static atmosphere is described. On this method hydrogen is removed by means of an uranium getter. (Author) 6 refs.

  11. Comparison of CaCO3 from Natural Sources and Artificial Carbonates as Activators of Solid-Phase Carburizing of Low-Carbon Steel

    Science.gov (United States)

    González-Angeles, A.; López-Cuevas, J.; Pitalúa-Díaz, N.

    2013-11-01

    The process of solid-phase carburizing of steel with the use of carbonates of different origin including chemical reagents, limestone and oyster shells is studied. The highest microhardness is obtained in the case of SrCO3, wheres Na2CO3 is shown to be the cheapest and most economically expedient carbonate. A good carburized layer can be obtained using a mixture of limestone and oyster shells.

  12. The efficiency of different types of wood charcoal on increasing carbon content on surfaces of low carbon steel in the pack carburizing process

    Directory of Open Access Journals (Sweden)

    Narongsak Thammachot

    2014-09-01

    Full Text Available The purpose of this research is to compare the efficiency of five types of wood charcoal, eucalyptus, coconut shell, tamarind, bamboo and cassava root in increasing carbon content on surfaces of low carbon steel by the pack carburizing process. The experiment for pack carburized low carbon steel (grade AISI 1020 was conducted by using the different wood charcoals as carburizers, mixed with 10% limestone (by weight as the energizer. The carburizing temperature of 950°C, and carburizing times of 2, 4 and 6 hours were used in the experiment. After grinding, the specimens in each case were checked for carbon content by optical emission spectroscopy. Micro-Vickers hardness testing and microstructure inspections were carried out. The results of the experiment showed that the efficiency of eucalyptus charcoal as the carburizer (for increasing carbon content on surfaces of low carbon steel was higher than that of tamarind, cassava root, coconut shell and bamboo charcoals. The averages for carbon content were: 1.16, 1.06, 0.97, 0.83 and 0.77% respectively.

  13. Development and application of intelligent vacuum carburizing and quenching furnace%智能型真空渗碳淬火炉研制及应用

    Institute of Scientific and Technical Information of China (English)

    孙强; 胡东彪; 杨建军; 李宝军; 封亮

    2012-01-01

    Intelligent vacuum carburizing and quenching furnace with a powerful computer control system and expert system,according to workpiece material properties and the diffusion layer requirements automatically generated the initial parameters of vacuum carburizing process,solves the problems of vacuum carburizing carbon black,tar pollution and carburized layer uniformity and improves production stability and quality consistency,vacuum carburized to achieve intelligent automated production,improves quality of cementation,has been used successfully in the aviation industry carburizing high alloy steel and stainless steel.%智能型真空渗碳淬火炉具有功能强大的计算机控制系统和专家系统,可以根据工件材料特性和渗层要求等初始参数自动生成真空渗碳工艺,解决了困扰真空渗碳碳黑、焦油污染和渗层均匀性问题,提高了生产稳定性和质量一致性,实现真空渗碳淬火的智能化自动生产,提高了渗碳质量,已成功用于航空工业中高合金钢和不锈钢的渗碳。

  14. Hardness of Carburized Surfaces in 316LN Stainless Steel after Low Temperature Neutron Irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Byun, TS

    2005-01-31

    A proprietary surface carburization treatment is being considered to minimize possible cavitation pitting of the inner surfaces of the stainless steel target vessel of the SNS. The treatment gives a large supersaturation of carbon in the surface layers and causes substantial hardening of the surface. To answer the question of whether such a hardened layer will remain hard and stable during neutron irradiation, specimens of the candidate materials were irradiated in the High Flux Isotope Reactor (HFIR) to an atomic displacement level of 1 dpa. Considerable radiation hardening occurred in annealed 316LN stainless steel and 20% cold rolled 316LN stainless steel, and lesser radiation hardening in Kolsterised layers on these materials. These observations coupled with optical microscopy examinations indicate that the carbon-supersaturated layers did not suffer radiation-induced decomposition and softening.

  15. Rolling Contact Fatigue Properties of SAE 8620 Steel after Case Carburizing

    Institute of Scientific and Technical Information of China (English)

    Yan-guang CAO; Le XU; Gou-qiang ZHANG; Jie SHI; Mao-qiu WANG

    2016-01-01

    Rolling contact fatigue (RCF)properties of SAE 8620 steel after case carburizing have been investigated under two contact stresses of 4·0 and 5·5 GPa.Results show that the RCF life ranges from 2·5×106 to 3×107 cycles un-der the contact stress of 5·5 GPa,while it can be more than 1×108 cycles under the contact stress of 4·0 GPa.The rated fatigue life L10 (lives with the 10% failure)is also drastically shortened from 9·8×106 to 5·4×105 cycles when the contact stress is increased from 4·0 to 5·5 GPa.Theoretical calculations and fractographs show that the maximum shear stress and the contact area increase with increasing the contact stress,making RCF tend to occur earlier.

  16. Reference measurements in a carburizing atmosphere. Pt. 1; Referenzmessungen in der Aufkohlungsatmosphaere. T. 1

    Energy Technology Data Exchange (ETDEWEB)

    Mikulovic, Dzo; Ehmeier, Florian [MESA Electronic GmbH, Geretsried (Germany); Zivanovic, Dragan [Nis Univ. (RS). Fakultaet fuer Elektrotechnik; MESA Electronic GmbH, Nis (RS)

    2010-06-15

    The most important parameters for control of carburizing process are the temperature and the C-potential of atmosphere. Temperature normally is measured by means of thermocouples. For control of C-potential measurement of oxygen partial pressure of furnace atmosphere by in-situ O{sub 2}-probes and Lambda probes became accepted. The thermocouples as well as the probes for measurement of residual oxygen gradually lose in accuracy. Therefore reference measurements for adjustment of temperature and C-potential are essential for an exact control. Within this article the reasons for incorrect measurements with thermocouples and O{sub 2}-probes, respectively L-probes will be explained. The appropriate reference measurements for correction of these faults are also described. Furthermore it is explained what has to be observed with these reference measurements and which information is given thereby about furnace atmosphere, especially with the gas analysis by means of a gas analyzer. (orig.)

  17. Control of Heat-Resistant Steel Carburized Layer Structure. Part II

    Science.gov (United States)

    Semenov, M. Yu.

    2013-09-01

    In the first part of the article, published in the previous issue of this journal, on the basis of studying features of the process a physical and mathematical model is presented of carbide formation during heat-resistant steel vacuum carburizing based on the example of VKS-5. In the second part of this article on the basis of analyzing the calculation model physical features are presented for formation of cementite type carbide phase taking account of steel VKS-5 alloying with chromium and nickel, and also temperature. Simultaneously, features of special molybdenum, tungsten, vanadium and niobium carbide formation are considered. The expediency of increasing chromium content in a new generation of heat-resistant steels alloyed with nickel is substantiated.

  18. Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears

    Science.gov (United States)

    Townsend, Dennis P.; Patel, P. R.

    1988-01-01

    Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

  19. Modeling of acetylene pyrolysis under steel vacuum carburizing conditions in a tubular flow reactor.

    Science.gov (United States)

    Khan, Rafi Ullah; Bajohr, Siegfried; Graf, Frank; Reimert, Rainer

    2007-03-02

    In the present work, the pyrolysis of acetylene was studied under steel vacuum carburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from 650 degrees C to 1050 degrees C. The partial pressure of acetylene in the feed mixture was 10 and 20 mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressure of the mixture was 1.6 bar. A kinetic mechanism which consists of seven species and nine reactions has been used in the commercial computational fluid dynamics (CFD) software Fluent. The species transport and reaction model of Fluent was used in the simulations. A comparison of simulated and experimental results is presented in this paper.

  20. Carburization of austenitic and ferritic alloys in hydrocarbon environments at high temperature

    Directory of Open Access Journals (Sweden)

    Serna, A.

    2003-12-01

    Full Text Available The technical and industrial aspects of high temperature corrosion of materials exposed to a variety of aggressive environments have significant importance. These environments include combustion product gases and hydrocarbon gases with low oxygen potentials and high carbon potentials. In the refinery and petrochemical industries, austenitic and ferritic alloys are usually used for tubes in fired furnaces. The temperature range for exposure of austenitic alloys is 800-1100 °C, and for ferritic alloys 500-700 °C, with carbon activities ac > 1 in many cases. In both applications, the carburization process involves carbon (coke deposition on the inner diameter, carbon absorption at the metal surface, diffusion of carbon inside the alloy, and precipitation and transformation of carbides to a depth increasing with service. The overall kinetics of the internal carburization are approximately parabolic, controlled by carbon diffusion and carbide precipitation. Ferritic alloys exhibit gross but uniform carburization while non-uniform intragranular and grain-boundary carburization is observed in austenitic alloys.

    La corrosión a alta temperatura, tal como la carburación de materiales expuestos a una amplia variedad de ambientes agresivos, tiene especial importancia desde el punto de vista técnico e industrial. Estos ambientes incluyen productos de combustión, gases e hidrocarburos con bajo potencial de oxígeno y alto potencial de carbono. En las industrias de refinación y petroquímica, las aleaciones austeníticas y ferríticas se utilizan en tuberías de hornos. El rango de temperatura de exposición para aleaciones austeníticas está entre 800-1.100°C y para aleaciones ferríticas está entre 500-700°C, con actividades de carbono ac>1 en algunos casos. En tuberías con ambas aleaciones, el proceso de carburación incluye deposición de carbón (coque en el diámetro interno, absorción de carbono en la superficie

  1. Nitrocarburizing with independently-controlled nitriding and carburizing potentials; Nitrocarburieren mit unabhaengig geregeltem Nitrier- und Carburierpotenzial

    Energy Technology Data Exchange (ETDEWEB)

    Winter, K.M. [PROCESS-ELECTRONIC GmbH, Heiningen (Germany)

    2006-05-15

    Nitrocarburizing, a short-cycle nitriding, is a well-known heat treatment for improving corrosion and wear resistance of work pieces. In contrast to long-cycle nitriding, where nitrogen diffuses into the steel surface to achieve a case depth similar to carburizing, nitrocarburizing over saturates the surface with nitrogen and carbon in order to change the iron alpha structure into gamma prime (Fe{sub 4}N) and later into epsilon (Fe{sub 2-3}[NC]). The hexagonal closed-packed epsilon has a very low friction and a high chemical resistance. This article will show the influence of different compositions in N and C created using a standard industrial pit-type furnace equipped with a control system capable of measuring and controlling K{sub N} and K{sub C} independently and at the same time. (orig.)

  2. Thermoelectric generating system attached to a carburizing furnace at Komatsu Ltd., Awazu Plant

    Science.gov (United States)

    Kaibe, H.; Makino, K.; Kajihara, T.; Fujimoto, S.; Hachiuma, H.

    2012-06-01

    At the end of October 2009, KELK Ltd. started a field test of the thermoelectric generation system at a carburizing furnace of Komatsu Ltd., Awazu Plant. Residual carburizing gas based on CO, H2 and N2 is burned resulting that 20-30 kW range of flame constantly heats up the hot side of TEG. A single unit of TEG consists of 16 of the Bi-Te thermo-modules, each of which has a size of 50 × 50 × 4.2 mm3 and can generate 24W under the circumstance of 280 °C and 30 °C of hot side and cold side temperature, respectively [1]. 16 modules are separated into 4 groups and they are connected electrically depending on design concept, namely in case of focusing on reliability, parallel connection are used and in case of on simplicity and high-voltage transmission, series connection is preferably employed. The module is being life-time tested at various conditions. For instance, 10,000 of heat cycling under the hot side temperature between 250 and 50 °C with a constant cold side temperature at 30 °C gives within a few percent degrade. Both buck-and booster-type DC/DC converters controlled by one chip computer were set up and Maximum Power Point Tracking (MPPT) was well facilitated to search for the maximum output power depending on the hot and cold temperature. The electric output power from the 16 modules is summed up to charge 4 lead storage batteries (12V-65Ah) and then through DC/AC inverters electricity goes to LED light tubes inside the factory. 214 W can be generated and 180 W is delivered to the batteries.

  3. 渗碳气体对201奥氏体不锈钢低温离子渗碳效果的影响%Effect of Carburizing Gases on Low Temperature Plasma Carburization of 201 Austenitic Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    王宇; 赵程

    2012-01-01

    用不同的渗碳气体对201奥氏体不锈钢进行了低温离子渗碳(DCPC)处理.实验证明,甲烷和乙炔均可在不锈钢表面形成一层无碳化铬析出的碳的过饱和固溶体(Sc相),使其表面的硬度和耐蚀性均有较大幅度的提高.但用甲烷作为渗碳气体处理的不锈钢表面有一层黑膜,破坏了不锈钢原有的光泽;而用乙炔作为渗碳气体不仅可以获得较为光亮的表面色泽,同时其硬度和耐蚀性也有进一步的提高.%The low temperature plasma carburization (DCPC) of 201 austenitic stainless steel has been done by using different carburizing gases. The results show that CH4 and C2 H2 can form a layer of carbon supersaturated solid solution (i. e. the Sc phase) on the steel surface without chromium carbide precipitation, so the surface hardness and corrosion resistance are greatly improved. But a layer of black film will form on the metal surface when CH4 is used as carburizing gases, which will destroy the original luster of stainless steel, when C2 H2 is used as carburizing gases, not only bright surface luster can be obtained, but also the hardness and corrosion resistance can be greatly improved.

  4. Study of the 1.25Cr-1Mo-0.25V steel microstructure after a carburization phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Simonetti, S., E-mail: ssimonet@uns.edu.ar [Departamento de Fisica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Departamentos de Ciencias Basicas e Ingenieria Mecanica, Universidad Tecnologica Nacional, 11 de Abril 461, 8000 Bahia Blanca (Argentina); Lanz, C. [Departamento de Ingenieria, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina); Brizuela, G.; Juan, A. [Departamento de Fisica, Universidad Nacional del Sur, Av. Alem 1253, 8000 Bahia Blanca (Argentina)

    2010-08-20

    We studied the changes in the structure and carbide particle size in 1.25Cr-1Mo-0.25V steel under 600 deg. C and 168 MPa, after 4000 h service. We used microscopy and microanalysis techniques to analyze the carbide particles. We performed a complementary theoretical study on the chemical bonding and electronic structure of the carbide-Fe matrix interaction. The results contribute to the understanding of the changes in the alloy microstructure caused by the carburization phenomenon.

  5. Tribotechnical and Energy Assessment of Parts of Working Members of Cultivating Machines After Carburizing and Laser Hardening

    Science.gov (United States)

    Pyndak, V. I.; Novikov, A. E.

    2016-07-01

    Results of experimental studies of low-carbon steel 20 and high-carbon steels of types 70 and 65G after carburizing, heat treatment and laser hardening are presented. The variation of the microhardness of the surface layers of the steels and of their wear resistance due to different variants of hardening is determined. Optimum modes of treatment aimed at raising the strength and wear resistance are suggested for the steels used for working members of cultivating machines.

  6. The Synergy of the Surface Layer after Carburizing of Tool Steel as a Measure of Operational Quality

    Directory of Open Access Journals (Sweden)

    Wencel, Z.

    2007-01-01

    Full Text Available In the paper the results of the investigation on surface layer of carburized X150CrMoV12-1 tool steel are presented. Abrasive wearing of the surface was determined according the ASTM G77-98 method. The microstructure of the matrix and distribution of carbides were observed in a Scanning Electron Microscope (SEM. A correlation between the investigated parameters (microstructure/carbides distribution was found.

  7. Hard Chromium Electroplating and Improvement the Properties by the Thermo Chemical Treatments (Solid Carburizing of Low Carbon Steel

    Directory of Open Access Journals (Sweden)

    Ahmed Salloum Abbas

    2009-01-01

    Full Text Available In this research the hard chromium electroplating process, which is one of the common methods of overlay coating was used, by using chromium acid as source of chromium and sulphuric acid as catalyst since the ratio between chromic acid and sulphuric acid is (100 : 1 consequently. Plating process was made by applying current of density (40 Amp / dm2 and the range of solution temperature was (50 – 55oC with different time periods (1-5 hr. A low carbon steel type (Ck15 was used as substrate for hard chromium electroplating. Solid carburization was carried out for hard chromium plating specimen at temperature (925oC with time duration (2 hr to be followed with quenching and tempering. The phase analysis was conducted by using X– ray diffraction. The examination results show that the chromium carbides in plating layer were (Cr23C6, Cr7C3. The microhardness of hard chromium plating specimen was measured, and the results show that the high hardness was about (907HV. After solid carburization the hardness values increase and the results show that the higher hardness for chromium plating layer on low carbon steel surface was (1276 HV. Wear apparatus type (Pin on Disc was used to study dry sliding wear properties of low carbon steel (As received and hard chromium plating specimens and solid carburized. The effect of applied normal load on wear rate was studied with weighting method using five normal loads (5, 10, 15, 20, 25 N at constant sliding speed (2.198 m / sec. The results reveal that the wear rate increases with the increasing of applied normal load. A good improvement in wear resistance was noticed for hard chromium plating specimens as compared with substrate specimen. It was also seen that, the improvement in wear resistance was (94% as compared with substrate metal when carburizing treatment is carried out on hard chromium plating specimens.

  8. Carbon diffusion and phase transformations during gas carburizing of high-alloyed stainless steels: Experimental study and theoretical modeling

    Science.gov (United States)

    Turpin, T.; Dulcy, J.; Gantois, M.

    2005-10-01

    Gas carburizing of high-alloyed stainless steels increases surface hardness, as well as the overall mechanical characteristics of the surface. The growth of chromium-rich carbides during carbon transfer into the steel causes precipitation hardening in the surface, but decreases the chromium content in solid solution. In order to maintain a good corrosion resistance in the carburized layer, the stainless steel composition and the carburizing process need to be optimized. To limit the experimental work, a methodology using software for modeling the thermodynamic and kinetic properties in order to simulate carbon diffusion and phase transformations during gas carburizing is presented. Thermodynamic calculations are initially used to find the optimum parameters ( T, carbon wt pct, etc.) in order to maintain the highest Cr and Mo contents in the austenitic solid solution. In a second step, kinetic calculations using the diffusion-controlled transformations (DICTRA) software are used to predict how the amount of the different phases varies and how the carbon profile in the steel changes as a function of time during the process. Experimental carbon profiles were determined using a wavelength-dispersive spectrometer for electron-probe microanalysis (WDS-EPMA), while carbide compositions were measured by energy-dispersive spectroscopy_X (EDS_X) analyses. A good agreement between calculated and experimental values was observed for the Fe-13Cr-5Co-3Ni-2Mo-0.07C and the Fe-12Cr-2Ni-2Mo-0.12C (wt pct) martensitic stainless steels at 955 °C and 980 °C.

  9. Enhanced wear and fatigue properties of Ti-6Al-4V alloy modified by plasma carburizing/CrN coating.

    Science.gov (United States)

    Park, Y G; Wey, M Y; Hong, S I

    2007-05-01

    In this study, a newly developed duplex coating method incorporating plasma carburization and CrN coating was applied to Ti-6Al-4V and its effects on the wear resistance and fatigue life were investigated. The carburized layer with approximately150 microm in depth and CrN coating film with 7.5 microm in thickness were formed after duplex coating. Hard carbide particles such as TiC And V(4)C(3) were formed in the carburized layer. XRD diffraction pattern analysis revealed that CrN film had predominant [111] and [200] textures. The hardness (Hv) was significantly improved up to about 1,960 after duplex coating while the hardness value of original Ti-6Al-4V was 402. The threshold load for the modification and/or failure of CrN coating was measured to be 32 N using the acoustic emission technique. The wear resistance and fatigue life of duplex-coated Ti-6Al-4V improved significantly compared to those of un-treated specimen. The enhanced wear resistance can be attributed to the excellent adhesion and improved hardness of CrN coating film for the duplex-coated Ti-6Al-4V. The initiation of fatigue cracks is likely to be retarded by the presence of hard and strong layers on the surface, resulting in the enhanced fatigue life.

  10. Evaluation of Important Factors Affecting Quench Distortion of Carburized Hypoid Gear with Shaft by Using Computer Simulation Methods

    Institute of Scientific and Technical Information of China (English)

    Tsuyoshi Sugimoto; Youichi Watanabe

    2004-01-01

    To minimize quenching distortion and dispersion, carburizing and quenching process conditions must be optimized; this includes the parts racking design used for quenching. We investigated some factors affecting carburized quenching distortion with an experiment using a hypoid gear having a shaft and with numerical simulation methods. The experimental results and those obtained from simulation were generally in agreement. Focusing on the surface temperature distribution in the gear, we studied quenching distortion characteristics in terms of changes in tooth profile and helix deviation. In our experiments, distortions occur during quenching in 373 K oil after austenitized temperature treatments conducted with various attitudes. We calculated the distortions by simulating the carburized oil-quenching process for the hypoid gear. Our results show large differences between the cooling rates of the tooth toe, middle section, and heel edges,and these greatly influence the change in tooth profile and helix deviation. We found that reducing the differences in temperatures on the gear surfaces during quenching is most important for minimizing the quench distortion of the hypoid gear.

  11. Experimental method for characterization of fatigue behaviour of carburized layers; Pruefkonzept zur experimentellen Bestimmung des Ermuedungsverhaltens von einsatzgehaerteten Werkstoffzustaenden

    Energy Technology Data Exchange (ETDEWEB)

    Kleemann, Andreas; Thumser, Rayk; Kleemann, Susanne; Winge, Joerg; Gerth, Uwe [Bauhaus Univ. Weimar (Germany). Materialforschungs- und -pruefanstalt

    2011-07-01

    Fatigue data of material states with different carbon contents are necessary for calculation of carburized parts. Experimental results on the correlation of local material structure and local endurance are not available. Up to now only carburized notched specimens and components have been investigated. In this investigation a new tube specimen with homogenous carbon content in the wall resulting from carburization process was developed. Carbon contents of 0.18 %, 0.40 %, 0.55 % und 0.70 % in the thin wall tube specimen have been tested. Specimens were loaded with cyclic internal and monotonic external pressures. Special test rig with two pressure intensifier is introduced. With the aid of the cyclic internal and constant external pressure the whole Haigh-diagram with ratios of pressure or stress of R = {infinity} until R = 0.5 could be covered. Main load direction in the tube specimen is perpendicular to the steel rods axis. Results obtained for the used 20MnCrB5 steel grade show the same endurance limit for different carbon contents or hardness, respectively, and are significantly affected by big non-metallic inclusions. (orig.)

  12. Non-vacuum electron-beam carburizing and surface hardening of mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Bataev, I.A., E-mail: ivanbataev@ngs.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Golkovskii, M.G., E-mail: M.G.Golkovski@inp.nsk.su [Budker Institute of Nuclear Physics SB RAS, Lavrentieva Prospect 11, 630090 Novosibirsk (Russian Federation); Losinskaya, A.A., E-mail: anna.losinskaya@mail.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Bataev, A.A., E-mail: bataev@adm.nstu.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Popelyukh, A.I., E-mail: aip13@mail.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation); Hassel, T., E-mail: hassel@iw.uni-hannover.de [Leibniz University, Welfengarten 1, 30167 Hannover (Germany); Golovin, D.D., E-mail: ddgolovin@yandex.ru [Novosibirsk State Technical University, K. Marks 20, 630092 Novosibirsk (Russian Federation)

    2014-12-15

    Highlights: • Steel specimens were carburized by non-vacuum electron-beam cladding. • The depth of the clad layers reached 2.6 mm. • The cladding rate was 1.8 m{sup 2}/h, the quenching rate 12.6 m{sup 2}/h. • The microhardness of the quenched and tempered layers reached 8 GPa. - Abstract: In this paper, we study the structure, microhardness, and tribological properties of surface layers of mild (0.19% C) steel, which was formed by electron-beam cladding with an iron–graphite powder mixture followed by quenching and tempering. A 1.4 MeV electron beam that was extracted into air was used. Cladding of steel with the iron–graphite mixture at a beam current of 24 and 26 mA formed a hypoeutectic cast iron layer (2.19% C) and a hypereutectoid steel (1.57% C) layer, which were 2.0 and 2.6 mm thick, respectively. The microhardness of the surface-quenched and tempered steel and cast iron layers was 7 and 8 GPa, respectively. Electron-beam quenching of the surface layers of hypoeutectic cast iron was accompanied with multiple cracking. During the quenching of the 1.57% C steel layer, crack formation was not observed. In friction tests against fixed and loose abrasive particles, the surface layers of hypereutectoid steel and hypoeutectic cast iron that were produced by electron-beam cladding and quenching had lower wear rates than mild steel after pack carburizing, quenching, and tempering. In the sliding wear tests, the cast iron clad layer, which was subjected to electron-beam quenching and tempering, exhibited the highest wear resistance. Electron-beam treatment can be used to harden local areas of large workpieces. It is reasonable to treat clad layers of high-carbon steel with electron-beam quenching and tempering. To prevent multiple cracking, white cast iron layers should not be quenched.

  13. 1Cr11Ni2W2MoV不锈钢气体渗碳工艺%Gas Carburizing Process for 1Cr11Ni2W2MoV Stainless Steel

    Institute of Scientific and Technical Information of China (English)

    杨亚宁; 张波; 卢华

    2011-01-01

    介绍了1Cr11Ni2W2MoV不锈钢在多用炉中低温气体渗碳的方法,解决了该材料低温渗碳层不均匀的问题.结果表明:零件渗碳前经吹砂或磷化,渗碳时通人NH,能够保证渗碳层均匀.%The gas carburizing process at low temperature in multi-furnace for 1Cr11Ni2W2MoV stainless steel was introduced.The problem of non uniform carburizing coating was solved.The results show that the carburized case uniformity can be ensured through sand blasting or phosphating before carburizing, and NH3 is filled during carburizing.

  14. Enhancing the wear resistance of case carburized steel (En 353) by cryogenic treatment

    Science.gov (United States)

    Bensely, A.; Prabhakaran, A.; Mohan Lal, D.; Nagarajan, G.

    2005-12-01

    All mechanical components that undergo sliding or rolling contact are subject to some degree of wear. So wear is an important tribological phenomenon while studying the failure of components. The observed frequent failure of crown and pinion due to wear and fatigue lead to this study on effect of cryogenic treatment on the wear resistance of case carburized steel (En 353). This paper deals with the pin on disk wear test without lubrication as per ASTM standard, designation: G 99-95A. The test was carried out for three different load conditions and seven sliding speeds for the samples, which has undergone three different treatment conditions namely conventional heat treatment (CHT), shallow cryogenic treatment (SCT) and deep cryogenic treatment (DCT). It has been found that the wear resistance has been considerably increased due to shallow cryogenic treatment and deep cryogenic treatment includes much more improvement in wear resistance when compared to conventional heat treatment. Also it is concluded that for better wear resistance, it is advisable to go for deep cryogenic treatment. The results are consistent with the previous studies reported in the literature on cryogenic treatments for other materials.

  15. Calibration of eddy current carburization measurements in ethylene production tubes using ion beam analysis

    Energy Technology Data Exchange (ETDEWEB)

    Stevens, K J [Materials Performance Technologies, Industrial Research Ltd, PO Box 31-310, Lower Hutt (New Zealand); Trompetter, W J [Rafter Laboratory, Institute of Geological and Nuclear Sciences, PO Box 31-312, Lower Hutt (New Zealand)

    2004-02-07

    Nuclear reaction analysis using a {sup 12}C(d, p{sub 0}){sup 13}C reaction and a {sup 16}O(d, p{sub 1}){sup 17}O reaction, with 1.02 MeV deuterons in an accelerator microprobe, has been used to produce quantitative linescans of the carbon and oxygen levels in ex-service ethylene pyrolysis tubes of HPM, HK40 and Manaurite XM alloy. Particle induced x-ray emission in the ion beam microprobe and energy dispersive analysis of x-rays in a scanning electron microscope were used for linescans of the heavier elements (Cr, Ni, Fe, Si and Ti). The composition linescans were used to calibrate the response and accuracy of an eddy current probe system for measuring carburization near the inner surface of the tubes. The influence of the ferromagnetic outer oxide surface layers has been clarified. A two-dimensional ANSYS finite element model (FEM) was used for interpretation of the eddy current scans. Good correlation was obtained between the ion beam analysis results, the impedance scans and the FEM.

  16. Calibration of eddy current carburization measurements in ethylene production tubes using ion beam analysis

    Science.gov (United States)

    Stevens, K. J.; Trompetter, W. J.

    2004-02-01

    Nuclear reaction analysis using a 12C(d, p0)13C reaction and a 16O(d, p1)17O reaction, with 1.02 MeV deuterons in an accelerator microprobe, has been used to produce quantitative linescans of the carbon and oxygen levels in ex-service ethylene pyrolysis tubes of HPM, HK40 and Manaurite XM alloy. Particle induced x-ray emission in the ion beam microprobe and energy dispersive analysis of x-rays in a scanning electron microscope were used for linescans of the heavier elements (Cr, Ni, Fe, Si and Ti). The composition linescans were used to calibrate the response and accuracy of an eddy current probe system for measuring carburization near the inner surface of the tubes. The influence of the ferromagnetic outer oxide surface layers has been clarified. A two-dimensional ANSYS finite element model (FEM) was used for interpretation of the eddy current scans. Good correlation was obtained between the ion beam analysis results, the impedance scans and the FEM.

  17. Austenite Grain Growth and Precipitate Evolution in a Carburizing Steel with Combined Niobium and Molybdenum Additions

    Science.gov (United States)

    Enloe, Charles M.; Findley, Kip O.; Speer, John G.

    2015-11-01

    Austenite grain growth and microalloy precipitate size and composition evolution during thermal processing were investigated in a carburizing steel containing various additions of niobium and molybdenum. Molybdenum delayed the onset of abnormal austenite grain growth and reduced the coarsening of niobium-rich precipitates during isothermal soaking at 1323 K, 1373 K, and 1423 K (1050 °C, 1100 °C, and 1150 °C). Possible mechanisms for the retardation of niobium-rich precipitate coarsening in austenite due to molybdenum are considered. The amount of Nb in solution and in precipitates at 1373 K (1100 °C) did not vary over the holding times evaluated. In contrast, the amount of molybdenum in (Nb,Mo)C precipitates decreased with time, due to rejection of Mo into austenite and/or dissolution of fine Mo-rich precipitates. In hot-rolled alloys, soaking in the austenite regime resulted in coarsening of the niobium-rich precipitates at a rate that exceeded that predicted by the Lifshitz-Slyozov-Wagner relation for volume-diffusion-controlled coarsening. This behavior is attributed to an initial bimodal precipitate size distribution in hot-rolled alloys that results in accelerated coarsening rates during soaking. Modification of the initial precipitate size distribution by thermal processing significantly lowered precipitate coarsening rates during soaking and delayed the associated onset of abnormal austenite grain growth.

  18. Pitting and Bending Fatigue Evaluations of a New Case-Carburized Gear Steel

    Science.gov (United States)

    Krantz, Timothy; Tufts, Brian

    2007-01-01

    The power density of a gearbox is an important consideration for many applications and is especially important for gearboxes used on aircraft. One approach to improving power density of gearing is to improve the steel properties by design of the alloy. The alloy tested in this work was designed to be case-carburized with surface hardness of Rockwell C66 after hardening. Test gear performance was evaluated using surface fatigue tests and single-tooth bending fatigue tests. The performance of gears made from the new alloy was compared to the performance of gears made from two alloys currently used for aviation gearing. The new alloy exhibited significantly better performance in surface fatigue testing, demonstrating the value of the improved properties in the case layer. However, the alloy exhibited lesser performance in single-tooth bending fatigue testing. The fracture toughness of the tested gears was insufficient for use in aircraft applications as judged by the behavior exhibited during the single tooth bending tests. This study quantified the performance of the new alloy and has provided guidance for the design and development of next generation gear steels.

  19. Analyses of quenching process during turn-off of plasma electrolytic carburizing on carbon steel

    Science.gov (United States)

    Wu, Jie; Liu, Run; Xue, Wenbin; Wang, Bin; Jin, Xiaoyue; Du, Jiancheng

    2014-10-01

    Plasma electrolytic carburizing (PEC) under different turn-off modes was employed to fabricate a hardening layer on carbon steel in glycerol solution without stirring at 380 V for 3 min. The quenching process in fast turn-off mode or slow turn-off mode of power supply was discussed. The temperature in the interior of steel and electron temperature in plasma discharge envelope during the quenching process were evaluated. It was found that the cooling rates of PEC samples in both turn-off modes were below 20 °C/s, because the vapor film boiling around the steel sample reduced the cooling rate greatly in terms of Leidenfrost effect. Thus the quench hardening hardly took place, though the slow turn-off mode slightly decreased the surface roughness of PEC steel. At the end of PEC treatment, the fast turn-off mode used widely at present cannot enhance the surface hardness by quench hardening, and the slow turn-off mode was recommended in order to protect the electronic devices against a large current surge.

  20. A metastable chromium carbide powder obtained by carburization of a metastable chromium oxide

    Energy Technology Data Exchange (ETDEWEB)

    Loubiere, S. [Univ. Paul-Sabatier, Toulouse (France). Lab. de Chimie des Materiaux Inorganique; Laurent, C. [Univ. Paul-Sabatier, Toulouse (France). Lab. de Chimie des Materiaux Inorganique; Bonino, J.P. [Univ. Paul-Sabatier, Toulouse (France). Lab. de Chimie des Materiaux Inorganique; Rousset, A. [Univ. Paul-Sabatier, Toulouse (France). Lab. de Chimie des Materiaux Inorganique

    1996-10-15

    A metastable Cr{sub 3}C{sub 2-x} carbide powder is prepared by carburization of a metastable chromium oxide in H{sub 2}-CH{sub 4} atmosphere under the appropriate conditions (temperature, dwell time and CH{sub 4} content). A very high specific surface area (greater than 210 m{sup 2} g{sup -1}) of the starting oxide is necessary to avoid the formation of the sole stable Cr{sub 3}C{sub 2} phase. The transformation from the stable Cr{sub 3}C{sub 2} to the metastable Cr{sub 3}C{sub 2-x} is observed for the first time. The driving force could be an epitaxial effect between Cr{sub 3}C{sub 2-x} and the surrounding graphite layer. This is consistent with the observation that the formation of graphite layers by CH{sub 4} cracking is easier in the Cr{sub 3}C{sub 2-x}-containing powders. (orig.)

  1. The wetting behaviour of silver on carbon, pure and carburized nickel, cobalt and molybdenum substrates

    Energy Technology Data Exchange (ETDEWEB)

    Hula, Robert C., E-mail: robert.hula@tuwien.ac.at [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164, A-1060 Wien (Austria); Edtmaier, Christian; Holzweber, Markus; Hutter, Herbert [Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164, A-1060 Wien (Austria); Eisenmenger-Sittner, Christoph [Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, A 1040 Wien (Austria)

    2010-05-01

    Properties such as thermal and electrical conductivity or the expansion behaviour of silver matrix composites with carbon based inclusions are strongly affected by the contact angle between carbon and silver. In order to promote wetting of carbon, insertion of metallic interlayers such as nickel, cobalt or molybdenum is a feasible approach. This paper presents contact angle measurements done with the sessile drop method on carbon substrates (glassy carbon, polycrystalline graphite) and on pure nickel, cobalt and molybdenum foils. The ability of these interlayer elements to lower the high contact angles of silver on glassy carbon (117 deg.) and polycrystalline graphite (124 deg.) under vacuum conditions was verified. Unlike nickel (30 deg.) and cobalt (26 deg.), molybdenum (107 deg.) nevertheless was not wettable by liquid silver (at 1273 K) under vacuum conditions. ToF-SIMS was used to identify oxygen on the surface, causing higher contact angles than expected. After oxide reduction a contact angle of 18 deg. on molybdenum was detected. Furthermore, the influence of carbon diffusion on the contact angle was investigated by gas phase carburization of the metal foils. ToF-SIMS and XRD identified dissolved carbon (Ni, Co) and carbide formation (Mo). However, only nickel and cobalt showed a slight decrease of the contact angle due to carbon uptake.

  2. Carburization of tungsten filaments in a hot-wire chemical vapor deposition process using 1,1,3,3-tetramethyl-1,3-disilacyclobutane.

    Science.gov (United States)

    Tong, L; Shi, Y J

    2009-09-01

    The alloying of tungsten filament when using 1,1,3,3-tetramethyl-1,3-disilacyclobutane (TMDSCB) in a hot-wire chemical vapor deposition reactor was systematically studied by scanning electron microscopy, Auger electron spectroscopy, analysis of the power consumed by the filament, and in situ mass spectrometric measurements of the gas-phase species produced in the process. Only carburization of the W filament was observed. The carburization is mainly caused by the interaction of methyl radicals with the filament. Graphite as well as both WC and W2C alloys can form on the filament surface, depending on the filament temperatures and source gas pressures. Both WC and graphite are converted to W2C with the diffusion of C into the filament. It is shown that filament carburization affects the consumption rate of the source gas and the intensities of gas-phase reaction products. Gas-phase reactions dominate at T or = 1800 degrees C.

  3. Design method of hardened depth for carburized gear%渗碳齿轮硬化层深度设计方法

    Institute of Scientific and Technical Information of China (English)

    肖伟中; 刘忠明; 袁玉鹏

    2014-01-01

    Based on the calculating method of contact strength , the shear stress distribution along the depth direction of gear surface was calculated, from the relationship of shear stress and shear strength , the lowest hardness distribution curve for carburized gear was obtained . Based on the lowest hardness distribution curve , the hardness distribution for carburized gears was designed , and the available hardened depth of carburized gears was obtained .%基于接触强度计算方法,计算出了齿轮沿齿面深度方向的剪切应力分布,通过剪切应力与剪切强度的关系,得到了渗碳齿轮最低要求的硬度分布曲线,在此基础上,设计出了齿轮硬化层硬度分布,得到有效硬化层深度。

  4. Research on Parts Process of V-shape Slot Carburizing Quenching%V型槽渗碳淬火零件加工工艺研究

    Institute of Scientific and Technical Information of China (English)

    陈惠娟; 黄玉方; 梁壮; 王健

    2012-01-01

    通过对V型槽渗碳淬火类零件的特性及加工难点的分析,研究V型槽渗碳淬火类零件的工艺总方案及加工工艺.主要针对2种不同结构类型的V型槽渗碳淬火类零件的加工工艺及加工过程进行分析,探讨V型槽渗碳淬火零件的特殊加工方法.通过对V型槽渗碳淬火类零件的生产加工和加工过程中的工艺改进与完善,摸索到了加工V型槽渗碳淬火零件的一些经验,供大家参考.%By analyzing the characteristics of V-shape slot carburizing quenching parts and the difficulties of processing, the paper mainly focused on the general plan and processing technology of the V-shape slot carburizing quenching parts. By analyzing parts processing technology and processing procedure of two different structures of the V-shape slot carburizing quenching, the paper discussed the specific processing method of the V-shape slot carburizing quenching parts. By making improvements and perfection of the production processing and the process technology of the V-shape slot carburizing quenching parts, we have got some experiences from the processing of the V-shape slot carburizing quenching parts for your reference.

  5. Did the First Iron Blacksmiths Learn to Carburize Iron? Part II: Experiments Showing That it is Very Likely That They Did

    Science.gov (United States)

    Verhoeven, J. D.; Pendray, A. H.; Dauksch, W. E.

    2016-08-01

    Results of short-time carburizing of wrought iron in a charcoal-fired furnace present strong evidence that our earliest blacksmith ancestors probably discovered how to carburize their bloomery iron and produced cutting and scraping tools superior to bronze tools shortly after they had learned to make this iron in the 1200-900 BC time period. Their bloomery iron needed to be forged to make useful tools and it seems likely that at least some of them heated the iron to the forging temperature in charcoal burning in their bloomery furnaces, the same arrangement as used here.

  6. Non-vacuum electron-beam carburizing and surface hardening of mild steel

    Science.gov (United States)

    Bataev, I. A.; Golkovskii, M. G.; Losinskaya, A. A.; Bataev, A. A.; Popelyukh, A. I.; Hassel, T.; Golovin, D. D.

    2014-12-01

    In this paper, we study the structure, microhardness, and tribological properties of surface layers of mild (0.19% C) steel, which was formed by electron-beam cladding with an iron-graphite powder mixture followed by quenching and tempering. A 1.4 MeV electron beam that was extracted into air was used. Cladding of steel with the iron-graphite mixture at a beam current of 24 and 26 mA formed a hypoeutectic cast iron layer (2.19% C) and a hypereutectoid steel (1.57% C) layer, which were 2.0 and 2.6 mm thick, respectively. The microhardness of the surface-quenched and tempered steel and cast iron layers was 7 and 8 GPa, respectively. Electron-beam quenching of the surface layers of hypoeutectic cast iron was accompanied with multiple cracking. During the quenching of the 1.57% C steel layer, crack formation was not observed. In friction tests against fixed and loose abrasive particles, the surface layers of hypereutectoid steel and hypoeutectic cast iron that were produced by electron-beam cladding and quenching had lower wear rates than mild steel after pack carburizing, quenching, and tempering. In the sliding wear tests, the cast iron clad layer, which was subjected to electron-beam quenching and tempering, exhibited the highest wear resistance. Electron-beam treatment can be used to harden local areas of large workpieces. It is reasonable to treat clad layers of high-carbon steel with electron-beam quenching and tempering. To prevent multiple cracking, white cast iron layers should not be quenched.

  7. The Proper Process Parameter of Brush Copperplating and the Minimun Thickness of Copper Film for Prevention of Carburization%防渗碳刷镀镀铜的工艺参数及镀层厚度选择

    Institute of Scientific and Technical Information of China (English)

    谢辅洲; 王桂芳; 郑玉丽

    2001-01-01

    In this paper, the effects of process parameter of brush copperplating on the copper film for prevention of carburization were studied; the relation between the time of carburization and the minimun thickness of copper film for prevention of carburization was established.%研究了用刷镀镀铜防渗碳时的工艺参数对镀层防渗碳效果的影响,及渗碳时间与防渗碳所需的最小镀层厚度之间的关系。

  8. Short-term creep properties of Ti-6Al-4V alloy subjected to surface plasma carburizing process

    Directory of Open Access Journals (Sweden)

    Verônica Mara Cortez Alves de Oliveira

    2015-10-01

    Full Text Available The aim of this study was to investigate the short-time creep behavior of Ti-6Al-4V by plasma carburizing, which was performed at 725 °C for 6 h in a 50% Ar – 45% H2 – 5% CH4 gas mixture. Nano and microhardness testing, optical microscopy, TEM, X-ray diffraction and optical profilometry were used to characterize the samples. Furthermore, short-term creep tests were performed under a constant tensile load in air at 600 °C using a dead-weight-creep-rupture machine. The carburizing treatment resulted in a compound layer measuring approximately 1.7 μm in thickness with a hardness of 815 HV and a composition of TiC0.66. The creep properties of the “Widmanstätten + carburized” specimens were improved relative to those of untreated specimens. TEM and fracture analysis indicated creep deformation process attributed mainly to α phase deformation and fracture by intergranular decohesion.

  9. Study of Effect of Quenching Deformation Influenced by 17CrNiMo6 Gear Shaft of Carburization

    Science.gov (United States)

    Pang, Zirui; Yu, Shenjun; Xu, Jinwu

    The 17CrNiMo6 steel is mainly used for the gear shaft of large modulus in many fields of heavy industry such as mining, transit, hoist, forging and so on[1]. The size of addendum circle and common normal line is changed a lot beyond the tolerance because of the long time of carburizing process and the out-of-step structural stress and thermal stress during the quenching process. And thus the posterior grinding efficiency and quality are influenced. In the paper comparison and analysis of the deformation affected by solid and hollow gear shafts were done and the methods of simulation and practice were both used. The results are as follows: the deformation of gear shaft was small before and after carburizing while that of gear shaft was large before and after quenching because of different cooling velocity, structure and hardness of each position. And the deformation of hollow was much smaller than that of solid. Therefore, if the hollow gear shaft is used, the waste of material will be decreased, and finishing cost will be reduced, and thus the technology of heat treatment will be optimized.

  10. Single-step thermal carburization synthesis of supported molybdenum carbides from molybdenum-containing methyl-silica

    Institute of Scientific and Technical Information of China (English)

    Juan Zou; Minglin Xiang; Bo Hou; Dong Wu; Yuhan Sun

    2011-01-01

    A novel synthesis route to obtain highly dispersed molybdenum carbides in porous silica is described. The synthesis was carried out by a single-step heat treatment of molybdenum-containing and methyl-modified silica (Mo-M-SiO2) in argon atmosphere at 973 K. Mo-M-SiO2 precursor was facilely obtained via a one-pot synthesis route, using (NH4)6Mo7O24·4H2O (AHM) as molybdenum sources and polymethylhydrosiloxane (PMHS) as silica sources at the initial synthetic step. The optimal C/Mo molar ratio in reaction system for complete carburization of molybdenum species was 7. The carburization process of molybdenum species followed a nontopotactic route involving a MoO2 intermediate phase, which was evidenced by XRD, N2 adsorption-desorption and in situ XPS. Formation mechanism of Mo-M-SiO2 precursor was also proposed by observation of the reaction between AHM and PMHS with TEM. Furthermore, by adding TEOS into silica sources and adjusting TEOS/PMHS mass ratio, crystal phase of molybdenum carbides transferred fromβ-Mo2C to α-MoC1-x, and SiO2 structure changed from microporous to micro/mesoporous. Catalytic performances of samples were tested using CO hydrogenation as a probe reaction. The supported molybdenum carbides exhibited high selectivity for higher alcohol synthesis compared with bulkβ-Mo2C and α-MoC1-x.

  11. Effect of the Content of Retained Austenite and Grain Size on the Fatigue Bending Strength of Steels Carburized in a Low-Pressure Atmosphere

    Science.gov (United States)

    Kula, P.; Dybowski, K.; Lipa, S.; Januszewicz, B.; Pietrasik, R.; Atraszkiewicz, R.; Wołowiec, E.

    2014-11-01

    The effect of the content of retained austenite and of the initial austenite grain size on high-cycle fatigue of two low-alloy steels 16MnCr5 and 17CrNi6-6 after carburizing in a low-pressure atmosphere (acetylene, ethylene and hydrogen) and subsequent high-pressure gas quenching is investigated.

  12. Silica-templated synthesis of ordered mesoporous tungsten carbide/graphitic carbon composites with nanocrystalline walls and high surface areas via a temperature-programmed carburization route.

    Science.gov (United States)

    Wu, Zhangxiong; Yang, Yunxia; Gu, Dong; Li, Qiang; Feng, Dan; Chen, Zhenxia; Tu, Bo; Webley, Paul A; Zhao, Dongyuan

    2009-12-01

    Ordered mesostructured tungsten carbide and graphitic carbon composites (WC/C) with nanocrystalline walls are fabricated for the first time by a temperature-programmed carburization approach with phosphotungstic acid (PTA) as a precursor and mesoporous silica materials as hard templates. The mesostructure, crystal phase, and amount of deposited graphitic carbon can be conveniently tuned by controlling the silica template (SBA-15 or KIT-6), carburizing temperature (700-1000 degrees C), the PTA-loading amount, and the carburizing atmosphere (CH(4) or a CH(4)/H(2) mixture). A high level of deposited carbon is favorable for connecting and stabilizing the WC nanocrystallites to achieve high mesostructural regularity, as well as promoting the carburization reaction. Meanwhile, large pore sizes and high mesoporosity of the silica templates can promote WC-phase formation. These novel, ordered, mesoporous WC/C nanocomposites with high surface areas (74-169 m(2) g(-1)), large pore volumes (0.14-0.17 cm(3) g(-1)), narrow pore-size distributions (centered at about 3 nm), and very good oxidation resistance (up to 750 degrees C) have potential applications in fuel-cell catalysts and nanodevices.

  13. INFLUENCE OF THE THERMAL PROCESS STAGE ON THE SIZE OF VALID GRAIN OF CONSTRUCTIONAL CARBURIZED STEEL GRADE 20CHN3A

    Directory of Open Access Journals (Sweden)

    S. P. Rudenko

    2016-01-01

    Full Text Available Results of studies of the kinetics of changes in actual grains during technological process at different stages of the manufacture of parts with the use of a universal metallographic etchant to identify borders of valid grains in rolling and stamping in carburizing layers and core parts made of alloy structure steel grades are presented.

  14. Study on Structure and Corrosion Resistance Analysis of Carburizing Organization of Austenitic Stainless Steel%奥氏体不锈钢渗碳层的组织及耐蚀强化性能研究

    Institute of Scientific and Technical Information of China (English)

    李朋; 潘邻; 张良界; 杨闽红; 朱云峰; 马飞; 王成虎

    2013-01-01

    针对常规渗碳工艺会削弱奥氏体不锈钢耐蚀性的问题,通过对现有气体渗碳技术进行改进,采用前处理活化、降低渗碳温度的方法,实现了奥氏体不锈钢渗碳兼顾表面强度与耐蚀性能的目标.采用该工艺对AISI304和AISI316奥氏体不锈钢进行渗碳处理,并分析渗层组织和性能,结果表明,在470℃条件下,AISI316不锈钢经气体渗碳处理后,渗碳层具有优异的耐蚀强化性能.%In view of the conventional carburization weakening austenitic stainless steel corrosion resistance problem,based on the existing gas carburizing technology was improved,using pretreatment activation,carburizing temperature reduction methods,realized the austenitic stainless steel carburized surface strength and corrosion resistant properties of the target.Using this process on AISI304,AISI316 austenitic stainless steel carburizing processing,and get the austenitic stainless steel for low temperature carburizing organization performance carries on the analysis and research,research shows that under the condition of 470 ℃,AISI316 stainless steel carburization treated by low temperature gas carburizing layer has excellent corrosion resistance improved performance.

  15. 渗碳温度对22Si2MnCrNi2MoA钢渗碳层的影响%Influence of carburizing temperature on microstructure and properties of carburized layers of a 22Si2MnCrNi2MoA steel

    Institute of Scientific and Technical Information of China (English)

    黄斌; 朱洪武; 杨忠; 周乐育; 刘雅政

    2013-01-01

    Influence of carburizing temperature on carburized layers of a 22Si2MnCrNi2MoA steel solid-carburized was studied by OM,SEM,XRD and hardness measurements.The relationship between carburizing temperature and carbon concentration,micro-hardness and retained austenite of the carburized layers were examined.The results indicate that with the carburizing temperature increasing for carburizing time of 6 h,the carbon concentration of the carburized layers gradually increases,and the distribution gradient of the carbon concentration gets smoother.The relationship between the micro-hardness of the carburized layers and carbon concentration obeys normal distribution.It is recommended that the surface carbon concentration of the carburized steel should be controlled in the range of 0.80% and 0.90% in order to obtain martensite microstructure with high hardness.When the surface carbon concentration is more than 0.80%-0.90%,aging treatment for a long time or deep cryogenic treatment are required to remove retained austenite in the carburized layers.%通过固体渗碳试验研究了加热温度对钎具用钢22Si2MnCrNi2MoA渗碳层的影响,分析了渗碳温度-碳浓度-显微硬度-残留奥氏体的关系以及残留奥氏体的控制措施.结果表明:当渗碳时间为6h时,随着渗碳温度的升高,渗碳层的碳浓度逐渐增加,碳浓度分布梯度越来越平缓.22Si2MnCrNi2MoA钢渗碳层的显微硬度-碳浓度关系符合正态分布.在渗碳处理过程中,为了使渗碳表层获得硬度很高的马氏体组织,22Si2MnCrNi2MoA钢渗碳层表面碳浓度应该控制在0.80% ~0.90%之间.当表面碳浓度超过0.80%~0.90%时,渗碳完成后需采取后续的工艺措施来消除已经存在的残留奥氏体,如采用长时间自然时效或深冷处理等.

  16. Microstructure and Cavitation Erosion Properties of Ceramic Coatings Fabricated on Ti-6Al-4V Alloy by Pack Carburizing

    Science.gov (United States)

    Li, Haibin; Cui, Zhenduo; Li, Zhaoyang; Zhu, Shengli; Yang, Xianjin

    2014-08-01

    In this study, Ti-6Al-4V alloy was processed by pack carburizing to improve the cavitation erosion behavior. X-ray diffraction and scanning-electron microscopy (SEM) analysis showed that a uniform and crack-free ceramic coating formed on the surface of the treated samples. The coating layer comprised primary TiC and less oxide. Cavitation erosion experiment results indicated that the treated samples have the factor of 3.44 to 6.68 increase in cavitation erosion resistance ( R e) as compared with the as-received sample. The ceramic coatings with high hardness and good metallurgical bonding were responsible for the enhanced cavitation erosion properties. When the coatings were treated at condition of high temperature and/or long time, the R e was enervated due to the thin oxide film formed at the outermost surface. Cavitation erosion mechanism for the coatings was characterized as brittle mode by SEM observation of the worn surfaces.

  17. Porous molybdenum carbide nano-octahedrons synthesized via confined carburization in metal-organic frameworks for efficient hydrogen production.

    Science.gov (United States)

    Wu, Hao Bin; Xia, Bao Yu; Yu, Le; Yu, Xin-Yao; Lou, Xiong Wen David

    2015-03-11

    Electrochemical water splitting has been considered as a promising approach to produce clean and sustainable hydrogen fuel. However, the lack of high-performance and low-cost electrocatalysts for hydrogen evolution reaction hinders the large-scale application. As a new class of porous materials with tunable structure and composition, metal-organic frameworks have been considered as promising candidates to synthesize various functional materials. Here we demonstrate a metal-organic frameworks-assisted strategy for synthesizing nanostructured transition metal carbides based on the confined carburization in metal-organic frameworks matrix. Starting from a compound consisting of copper-based metal-organic frameworks host and molybdenum-based polyoxometalates guest, mesoporous molybdenum carbide nano-octahedrons composed of ultrafine nanocrystallites are successfully prepared as a proof of concept, which exhibit remarkable electrocatalytic performance for hydrogen production from both acidic and basic solutions. The present study provides some guidelines for the design and synthesis of nanostructured electrocatalysts.

  18. Etudes sur la phase carbure de bore. Corrélations propriétés-composition

    OpenAIRE

    1982-01-01

    No english abstract; La connaissance du diagramme de phases bore-carbone, des propriétés physico chimiques et la structure du carbure de bore ont été approfondies. Dans ce but, nous avons mis en œuvre principalement deux méthodes de préparation de nos échantillons : ¤ la fusion au canon à électrons, ¤ la compression à chaud. Il faut noter que nous avons considérablement amélioré cette dernière méthode pour la rendre apte à la préparation en particulier d'échantillons constitués de bore pur ou...

  19. Monitoring preparation and phase transitions of carburized W(1 1 0) by reflectance difference spectroscopy.

    Science.gov (United States)

    Bachmann, Magdalena; Memmel, Norbert; Bertel, Erminald; Denk, Mariella; Hohage, Michael; Zeppenfeld, Peter

    2012-10-01

    Reflectance difference spectroscopy (RDS) is applied to follow in situ the preparation of clean and carburized W(1 1 0) surfaces and to study the temperature-induced transition between the R(15 × 3) and R(15 × 12) carbon/tungsten surface phases. RDS data for this transition are compared to data obtained from Auger-electron spectroscopy and low-energy electron diffraction. All techniques reveal that this transition, occurring around 1870 K, is reversible with a small hysteresis, indicating a first-order-like behaviour. The present results also prove a high surface sensitivity of RDS, which is attributed to the excitation of electronic p-like surface resonances of W(1 1 0).

  20. Precise gas carburizing quenching process of 18 Cr2 Ni4 WA steel bushes%18Cr2Ni4WA钢衬套的精密气体渗碳淬火热处理

    Institute of Scientific and Technical Information of China (English)

    李锋; 王新宇; 李世键; 韩培培; 于浩

    2016-01-01

    The influence of precise gas carburizing and isothermal quenching process on carburized layer hardness , depth and the microstructure of 18Cr2Ni4WA steel was studied .The results show that the carburized layer depth increases with the increasing of the total holding time, but the hardness profile becomes flat gradually .The longer of strong carburizing time , the deeper of carburized depth with the same total holding time .The longer of strong carburizing time , the lower of surface hardness with the same diffusion carburizing time .The optimized precise heat treatment process consists of holding temperature at 910 ℃, by carbon potential of strong carburizing stage at 1.20%and holding for 3 h, and then by carbon potential of diffusion stage at 0.80%and holding for 1 h,and then isothermally quenched in nitrate bath.With this optimized process , the typical carburized depth of (1.2 ±0.1) mm with favorable microstructure distribution is obtained . The process has been successfully applied in bushes production with satisfactory requirement of carburized depth , hardness profile and microstructure .%研究了精密气体渗碳等温淬火工艺对18Cr2Ni4WA钢渗层硬度、深度及显微组织的影响。结果表明,随着总渗碳保温时间的延长,渗层深度增加,但硬度曲线变得平缓;在相同总保温时间的情况下,强渗时间越长,渗层越深;而当扩散时间相同时,强渗时间越长,淬火后表层的硬度较低。优化的精密气体渗碳工艺为:保温温度均为910℃,强渗阶段碳势1.20%,保温3 h;扩散阶段碳势0.80%,保温1 h,渗碳后进行等温淬火,可以获得(1.2±0.1) mm渗层深度。渗碳淬火后渗层组织良好。该工艺成功应用于衬套零件的实际生产,满足了设计要求。

  1. 钛表面辉光无氢渗碳动力学与耐蚀性能研究%Study on Kinetics and Corrosion Resistance of Plasma Non-hydrogen Carburizing on Titanium Surface

    Institute of Scientific and Technical Information of China (English)

    华云峰; 李争显; 杨浩; 王宝云; 王彦峰; 姬寿长; 罗小峰; 杜继红

    2012-01-01

    C.P.Ti TA2 was carburized by double-glow plasma non-hydrogen carburizing technique. The carburizing kinetics was studied. The corrosion resistance of the carburized samples was evaluated in 3.5%NaCl and 80%H2SO4 water solution at 25 ℃. The results show that the thickness of carburized layer increases with increasing carburizing temperature and time. The relationship between the diffusion coefficient of carbon in carburized layer and the carburizing temperature accords with the Arrhenius manner. The value of diffusion activation energy is 13.6 kJ/mol (0.14 eV). The carburized sample has better corrosion resistance than Ti-0.2Pd and C.P.Ti. The corrosion rate of carburized layer is 0.00048 and 2.118 mm/a in 3.5%NaCl and 80%H2SO4 water solution, which is 77% and 50% of that of Ti-0.2Pd and 13% and 11% of that of C.P.Ti under the same condition, respectively.%采用辉光无氢渗碳方法,在工业纯钛TA2表面制备渗碳层,研究辉光无氢渗碳动力学以及渗碳试样在25℃、3.5% NaCl水溶液和25℃、80% H2SO4水溶液中的耐蚀性能.结果表明,渗碳层厚度随渗碳温度与时间的增加而增加,碳在渗碳层中的扩散系数与绝对温度之间符合Arrhenius关系式,扩散活化能为13.6 kJ/mol (0.14 eV).渗碳试样在25℃3.5% NaCl、80% H2SO4水溶液中的腐蚀速率分别为0.000 48 mm/a、2.118 mm/a,分别是Ti-0.2Pd的77%、50%,分别是TA2的13%、11%,耐蚀性能得到显著提高.

  2. 关于真空炉渗碳过程的初步试验研究%Preliminary experimental study about vacuum furnace carburizing process

    Institute of Scientific and Technical Information of China (English)

    黄晓辉; 于滢

    2013-01-01

    通过对SG13Cr4Mo4Ni4V钢真空渗碳过程的主要影响因素进行试验分析,初步摸索了各工艺参数之间的关系,为提高该钢种真空渗碳热处理质量提供了试验数据。%Through test analysis on main affecting factors of vacuum carburizing process of SG13Cr4Ni4V steel, the relationship between the process parameters was tried to ifnd out initially in order to provide test data for improving the quality of the steel vacuum carburizing heat treatment.

  3. 拖拉机齿轮的稀土低温渗碳%Low-temperature Carburizing with Rare Earth Elements for Tractor Gears

    Institute of Scientific and Technical Information of China (English)

    樊湘芳

    2001-01-01

    介绍了稀土低温渗碳工艺在拖拉机齿轮上的应用。通过具体的数据说明该工艺实施的方便性和节能效果。通过试验得出稀土低温渗碳工艺用于井式气体渗碳炉,生产周期可缩短15%,齿轮的质量也有所提高。%The application of low-temperature carburizing with rare earth elements for tractor gears is presented in this paper.The convenience and energy saving of the technology is demonstrated in details.It is concluded that by applying rare-earth low-temperature carburizing in pit-type furnace the production period can be shorten by 15 percent and the quality of the gears is improved.

  4. Effects of niobium additions on the structure, depth, and austenite grain size of the case of carburized 0.07% C steels

    Science.gov (United States)

    Islam, M. A.; Bepari, M. M. A.

    1996-10-01

    Carbon (0.07%) steel samples containing about 0.04% Nb singly and in combination with nitrogen were carburized in a natural Titas gas atmosphere at a temperature of 1223 K (950 °C) and a pressure of about 0.10 MPa for 1/2 to 4 h, followed by slow cooling in the furnace. Their microstructures were studied by optical microscopy. The austenite grain size of the case and the case depths were determined on baseline samples of low-carbon steels and also on niobium and (Nb + N) microalloyed steel samples. It was found that, when compared to the baseline steel, niobium alone or in combination with nitrogen decreased the thickness of cementite network near the surface of the carburized case of the steels. However, niobium in combination with nitrogen was more effective than niobium in reducing the thickness of cementite network. Niobium with or without nitrogen inhibited the formation of Widmanstätten cementite plates at grain boundaries and within the grains near the surface in the hypereutectoid zone of the case. It was also revealed that, when compared to the baseline steel, niobium decreased the case depth of the carburized steels, but that niobium with nitrogen is more effective than niobium alone in reducing the case depth. Niobium as niobium carbide (NbC) and niobium in the presence of nitrogen as niobium carbonitride, [Nb(C,N)] particles refined the austenite grain size of the carburized case, but Nb(C,N) was more effective than NbC in inhibiting austenite grain growth.

  5. Zircon Carburation Studies as Intermediate Stage in the Zirconium Fabrication; Estudios encaminados a la carburacion del circon como etapa intermedia en la obtencion de circonio

    Energy Technology Data Exchange (ETDEWEB)

    Almagro Huertas, V.; Saenz de Tejada Gonzalez, L.; Lopez Rodriguez, M.

    1963-07-01

    Zirconium carbide and carbonitride mixtures were obtained by Kroll's method.Reaction products have been identified by micrography and X-ray diffraction analysis. The optimum graphite content in the initial charge for the carburation reaction has been studied. zirconium, silicon and carbon content in the final product has been controlled as a function of current in the furnace and reaction time.Further chlorination of the final product was performed successfully. (Author) 16 refs.

  6. Experimental Study and Computer Simulation on Multicomponent Diffusion in Multiphase Dispersions During Solid Carburizing of HP40Nb and KHR45A Alloys

    Science.gov (United States)

    Zhao, Yanping; Gong, Jianming; Wang, Xiaowei; Shen, Limin; Li, Qingnan

    2015-10-01

    To simulate solid carburizing processes of HP40Nb and KHR45A alloys at 1273 K and 1373 K (1000 °C and 1100 °C), Thermo-Calc (Thermo-Calc Software, Inc., Stockholm, Sweden) and DICTRA (Thermo-Calc Software, Inc.) software analyses were performed. A model to treat multicomponent diffusion in multiphase dispersions was applied, where carbides are assumed to be distributed in face-centered cubic matrix and diffusion only occurs in the matrix. The time-dependent carbon flux determined by weight gain measurement was used as boundary condition in diffusion simulations. The calculated carbides are NbC, M23C6, and M7C3 ("M" stands for metal atoms), where M23C6 first precipitates, then M7C3 appears as carbon increases, and NbC covers the largest area of carbon content. The results show that carburization resistance is much better for KHR45A than HP40Nb due to the addition of elements (Si, Cr, Ni, and Nb). Microhardness measurements were also conducted to obtain the carburized case depths, and the results agreed well with the predicted calculations.

  7. 剪毛机支架体渗碳工艺的优化%The Optimum of Carburize Industrial Art on Shearing Machine Frame Foundation

    Institute of Scientific and Technical Information of China (English)

    吐尔逊·斯地克; 熊辉林

    2011-01-01

    By the shearing machine frame foundation with its material (number 08 steel), using solid-state carburize method, the carburize industrial art, organization and property have been studied in order to provide reasonable theoretical foundation for increasing resistance to wear of carburize layers. From test the optimal version has been reached in heating temperature of 950℃, insulated time of 4 h, catalyst proportion of 30%.%本文以剪毛机支架体材料08钢为研究对像,采用固体渗碳法,对渗碳的工艺,组织和性能进行研究,为提高渗碳层的耐磨性提供可靠的理论依据.通过试验得出加热温度为950℃,保温时间为6 h,催渗剂比例为30%的最优方案.

  8. Application of Carburization Technique in Nodular Iron Production%增碳技术在球墨铸铁生产中的应用

    Institute of Scientific and Technical Information of China (English)

    蒋毓良

    2011-01-01

    简单介绍了增碳剂的类型及选用原则;对影响增碳剂增碳率和增碳作用的因素进行了分析,指出在球墨铸铁生产中,应用增碳及铁液预处理工艺,可减少铁液杂质元素和有害元素的含量,降低炉料遗传性影响,增加石墨球数,改善球化率,提高材料的力学性能.%The sorts of carburizer and their selection and usage principle were introduced briefly. The factors influencing the carburizing rate and carburizing effect were analyzed. It was pointed out that application of carhurizing procesa and preconditioning process in the nodular iron production makes it possible to reduce content of the impurity elements and harmful elements. decrease the heredity effect of the melting charges, increase nodule count, improve nodularity and improve material mechanical properties.

  9. 齿轮激光淬火和渗碳淬火的经济性比较%Economic Comparison of Laser-hardened Gear and Carburized Gear

    Institute of Scientific and Technical Information of China (English)

    张欣; 郭子峰

    2014-01-01

    激光淬火是齿轮表面硬化的一个新工艺,与渗碳淬火相比,具有变形小等特点,具有广阔的应用前景。针对齿轮激光淬火和渗碳淬火两种不同工艺,从材料、工艺流程、制造成本等方面进行了比较,结果表明:齿轮激光淬火比渗碳淬火更加经济。%Laser hardening is a new method for surface hardening of gear tooth. It characteristics of little deformation after hardening compared with carburized gears, which can be widely used in the industries. According to the two dif-ferent heat treatments of gears, laser hardening and carburizing, the base materials, manufacturing process and produc-tion cost of two different hardened-gears are compared. The research results show that laser-hardened gears are eco-nomical compared to carburized gears.

  10. Synthetic Or Reformulated Fuels: a Challenge for Catalysis Carburants de synthèse ou reformulés : un défi pour la catalyse

    Directory of Open Access Journals (Sweden)

    Courty P.

    2006-12-01

    Full Text Available Despite comparative figures for wordwide crude oil and natural gas proven reserves, present time contribution of syngas chemistry to motorfuels remains marginal when the refining industry is faced to main constraints: market demand evolution, stringent specifications and environmental issues. Actually natural gas upgrading via syngas chemistry yields key products (e. g. methanol among which clean motorfuels (ethers, FT products should develop despite the huge investments required, mostly for syngas production. Main challenges and corresponding issues for catalysts and related technologies are identified for Fischer-Tropsch synthesis and motorfuels long-term reformulation. Among other, mastering the chain-growth (FT synthesis improving the FCC products: gasoline, and LCO for Diesel pool. All these issues need significant progresses in catalyst and technology to be solved. Lastly, our economical study, focused on Diesel-fuel production, shows up that clean diesel (from SR-LCO mixtures and FT Diesel reach similar production costs when cheap NG is available. In the future, FT middle distillates should amount to a few percent (5-150 Mt of the 1700-2000 Mt of transport middle distillates expected from oil refining. However they should more and more be a compulsory part of diesel pool if the level of investment for an FT process continues to decrease significantly. Malgré des réserves prouvées en pétrole et en gaz du même ordre de grandeur, la contribution de la chimie du gaz de synthèse à la production de carburants reste marginale, alors que l'industrie du raffinage est confrontée à des contraintes majeures : évolution de la demande, durcissement des spécifications des produits et contraintes environnementales. Cependant, la conversion chimique du gaz, via la chimie du gaz de synthèse, fournit des produits stratégiques (e. g. méthanol parmi lesquels les carburants propres (éthers, produits Fischer-Tropsch devraient se développer, bien

  11. Carburization of W- and Re-rich Ni-based alloys in impure helium at 1000 {sup o}C

    Energy Technology Data Exchange (ETDEWEB)

    Adharapurapu, Raghavendra R., E-mail: araghav@gmail.co [Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Kumar, Deepak; Zhu Jun [Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109 (United States); Pollock, Tresa M. [Materials Department, University of California, Santa Barbara, CA 93106 (United States)

    2011-01-15

    Research highlights: This work investigates the surface and bulk stability of W- and Re-rich Ni-based alloys under carburizing/oxidizing conditions (1000 {sup o}C) in order to understand the fundamental mechanisms of material degradation due to impurities in helium environment of the very high temperature helium-cooled reactor (VHTR). Depending on the alloy composition, carbides of type M{sub 6}C, M{sub 7}C{sub 3} or M{sub 23}C{sub 6} were observed, with a maximum carbon pickup between 0.06 and 0.12 wt.%. Alloys with high W content exhibited M{sub 6}C type carbides, whereas high Cr and low W alloys formed Cr-rich M{sub 23}C{sub 6} carbides. High additions of Re stabilized the M{sub 23}C{sub 6} phase due to its high solubility in these chromium-rich carbides. A continuous film of contiguous carbides (M{sub 6}C and M{sub 23}C{sub 6}) was observed in the grain boundaries; this is likely to be detrimental to the ductility and creep properties. During the first 50 h exposure, carbides were observed on the alloy surface as well as in the bulk with carbides precipitating in the grain interior and on the grain boundary. The (transient) surface carbides oxidized after prolonged exposure (100-225 h) forming stable Cr{sub 2}O{sub 3} oxide on the alloy surface. The work is particularly relevant to the development of strategies towards improvement of Ni-based alloys for intermediate heat exchangers (IHX) for service at 1000 {sup o}C in impure-He environment of the Next Generation Nuclear Plant (NGNP). - Abstract: The surface and microstructure stability of experimental W- and Re-rich Ni-based alloys in an impure-helium environment containing only CO and CO{sub 2} as impurities (ppm level) have been investigated at 1000 {sup o}C. All the alloys carburized during 50 h of exposure, and, depending on the alloy composition, different carbides of the type M{sub 6}C, M{sub 7}C{sub 3} and M{sub 23}C{sub 6} formed on the alloy surface, in grain interiors and at grain boundaries

  12. Application of PT9800 software to optimization of carburizing process for heavy-duty locomotive gear%PT9800软件在重载机车齿轮渗碳工艺优化中的应用

    Institute of Scientific and Technical Information of China (English)

    文超; 董雯; 谭小明; 王晓华

    2012-01-01

    利用PT9800软件进行了两段式渗碳工艺强扩比的模拟计算,据此优化了重载机车齿轮渗碳工艺并节省了20%的工艺时间。相应的验证试验也获得了满意的渗层金相组织、硬度梯度和预期的渗碳层深度,证明了PT9800计算的准确性,从而为渗碳工艺强扩比的合理选择和优化提供了依据。%The carburizing-diffusion ratio of two-stage carburizing technology was simulated by using PT9800 software.According to this simulation calculation,the carburizing process for heavy-duty locomotive gear was optimized and the process time was saved 20%.The expected microstructure,hardness distribution and case depth of the carburized layer were obtained by the relevant experiments,it is approved the reasonability and accuracy of PT9800 software,and provides evidence for choice and optimization of the carburizing-diffusion ratio.

  13. Equilibration of plain carbon and alloy steels with endothermic carburizing atmospheres: Part II. Oxidation of plain carbon and Armco steels during carburizing at 1000 °C and 1038 °C

    Science.gov (United States)

    Hwang, Jong-Il; Jhee, Tae-Gu; Kim, Young-Kyu; Hwang, Tae-Young

    2010-10-01

    Carbon contents by the weight gain of AISI type 1010 steel foils equilibrated with CO-CO2 mixtures at 1000 °C were 0.03 wt.% to 0.07 wt.% higher than those by chemical analysis at carbon potentials of 0.2 wt.%C to 0.7 wt.%C. The lower the carbon potential, the bigger the difference became. This difference of 0.05 wt.% to 0.08 wt.% was also measured when the same materials were equilibrated with CO-CO2 mixtures at 1038 °C at carbon potentials below 0.4 wt.%C. Oxygen analyses of these equilibrated steel foils confirmed that those differences of 0.03 wt.% to 0.07 wt.% and 0.05 wt.% to 0.08 wt.% were mainly due to the selective oxidation of manganese. When Armco steels and type 1010 steels were equilibrated simultaneously with endothermic-base carburizing atmospheres at 1038 °C, oxidation was negligible and the carbon contents of the both steels were identical at carbon potentials of 0.2 wt.%C to 1.4 wt.%C.

  14. EBSD analysis of tungsten-filament carburization during the hot-wire CVD of multi-walled carbon nanotubes.

    Science.gov (United States)

    Oliphant, Clive J; Arendse, Christopher J; Camagu, Sigqibo T; Swart, Hendrik

    2014-02-01

    Filament condition during hot-wire chemical vapor deposition conditions of multi-walled carbon nanotubes is a major concern for a stable deposition process. We report on the novel application of electron backscatter diffraction to characterize the carburization of tungsten filaments. During the synthesis, the W-filaments transform to W2C and WC. W-carbide growth followed a parabolic behavior corresponding to the diffusion of C as the rate-determining step. The grain size of W, W2C, and WC increases with longer exposure time and increasing filament temperature. The grain size of the recrystallizing W-core and W2C phase grows from the perimeter inwardly and this phenomenon is enhanced at filament temperatures in excess of 1,400°C. Cracks appear at filament temperatures >1,600°C, accompanied by a reduction in the filament operational lifetime. The increase of the W2C and recrystallized W-core grain size from the perimeter inwardly is ascribed to a thermal gradient within the filament, which in turn influences the hardness measurements and crack formation.

  15. Three-Dimensional (3-D) Atom Probe Tomography of a Cu-Precipitation-Strengthened, Ultrahigh-Strength Carburized Steel

    Science.gov (United States)

    Tiemens, Benjamin L.; Sachdev, Anil K.; Mishra, Raja K.; Olson, Gregory B.

    2012-10-01

    In an effort to reduce material cost, experimental steel alloys were developed that incorporated Cu precipitation in lieu of costly Co alloying additions in secondary hardening carburizing gear steels. This work utilizes three-dimensional atom probe tomography to study one of these prototype alloys and quantify the nanoscale dispersions of body-centered cubic (bcc) Cu and M2C alloy carbides used to strengthen these steels. The temporal evolution of precipitate, size, morphology, and interprecipitate interactions were studied for various tempering times. Findings suggest that Cu precipitation does act as a catalyst for heterogeneous nucleation of M2C carbides at relatively high hardness levels; however, the resultant volume fraction of strengthening carbides was noticeably less than that predicted by thermodynamic equilibrium calculations, indicating a reduced potency compared with Co-assisted precipitation. Microstructural information such as precipitate size and volume fraction was measured at the peak hardness condition and successfully used to recalibrate alloy design models for subsequent alloy design iterations.

  16. 井式炉渗碳工艺过程控制SE-607系统的应用%Application of carburizing process control system SE-607 for pit-type furnace

    Institute of Scientific and Technical Information of China (English)

    景晖

    2011-01-01

    The application case in Hangzhou Advance Gearbox Group Co.,Ltd.,of SE-607 pit-type furnace carburizing control system that was developed and researched by STANGE Electronic GmbH was introduced for the construction of hardware and software,carburizing workmanship,working principle of carbon potential regulation,carburizing process simulation and computer monitoring system.%以德国斯坦格电气有限公司设计制造的SE-607井式炉渗碳工艺过程控制系统在杭州前进齿轮箱厂的项目应用为实例,对该过程控制系统的软硬件结构、渗碳工艺、碳势控制原理、渗碳扩散模拟模块及上位机监控系统的组成进行介绍。

  17. 奥氏体不锈钢低温气体渗碳的组织性能%Structure and Properties of Anti-corrosion Carburized Layers in Austenitic Stainless Steels

    Institute of Scientific and Technical Information of China (English)

    李朋; 潘邻; 张良界; 杨闽红; 朱云峰; 马飞

    2013-01-01

    Low temperature carburizing process, such as salt bath carburizing and plasma carburizing can improve the surface strength of the austenite stainless steel, but reduce the corrosion resistant performance. A gas carburizing technology at low temperature was developed, which can both improve the surface strength and corrosion resistant performance. 304 and 316 austenitic stainless steel were carburized by low temperature carburizing process, and the hardness and performance was analized. The results show that the surface strength enhances, however, the corrosion resistance reduces with the temperature increase. The austenitic stainless steel shows good strength and corrosion resistance under the condition of 470 ℃.%低温盐浴渗碳、等离子渗碳等低温渗碳工艺在提高奥氏体不锈钢表面强度的同时,会降低其耐蚀性能.为克服上述缺陷,开发了一种高效兼顾表面强度与耐蚀性能的表面强化工艺的低温气体渗碳技术.采用该工艺对304、316奥氏体不锈钢进行渗碳处理,并对得到的奥氏体不锈钢低温渗碳组织性能进行分析.结果表明,随着温度升高,试样表面强度提高,而腐蚀性能下降.470℃是兼顾强化与耐蚀性能的低温气体渗碳工艺参数.

  18. Carburizing Inspection of Cracking Furnace Tube Using Magnetic Hysteresis Non-Destructive Evaluation Technique%磁滞无损评估技术在裂解炉管渗碳检测中的应用

    Institute of Scientific and Technical Information of China (English)

    刘德宇; 王宁辉; 张国庆; 李国瑞

    2015-01-01

    Large tube type fuel heating furnaces are important and essential equipments, with a wide range of applications in the petroleum and chemical industry, in which the failure modes of furnace tubes are mostly caused by carburizing. To estimate the effect of magnetic hysteresis non-destructive evaluation technique on carburizing inspection, both new and the three-years-service cracking furnace tubes were performed carburizing test. Different carburized depth of tubes were got and their coercivity was tested. The results showed that there is a good relationship between the coercivity and carburized case depth, which would be a great potential applications in the carburizing inspection of tube.%大型管式燃料加热炉是石油化工企业里广泛应用且必不可少的重要设备,其中炉管的失效大多由渗碳引起。为了评价磁滞无损评估技术在渗碳层厚度检测中应用的有效性,对未服役和服役3年的裂解炉炉管进行渗碳实验,得到不同渗碳层厚度的炉管,并采集磁滞参数矫顽力,结果表明,矫顽力与渗碳层厚度具有很好的对应关系,在炉管渗碳检测中具有很大的应用前景。

  19. 汽车零部件丙烷气体渗碳时气氛净化工艺及效果%Atmosphere Purification Technology and Effect of Gas Carburizing for Automobile Spare Parts

    Institute of Scientific and Technical Information of China (English)

    张道于; 张铁军

    2013-01-01

    采用分子筛作为净化剂,可使渗碳气氛中的水分稳定地控制在较低水平.采用净化后的丙烷气体渗碳,产品质量得到明显提高,生产成本显著下降.%Using molecular sieve as the purifying agent, water in the carburizing atmosphere can be stably controlled at a lower level. Using purified propane gas carburizing, the product quality can be significantly improved, production costs decrease significantly.

  20. The effect of molybdenum on niobium, titanium carbonitride precipitate evolution and grain refinement in high-temperature vacuum carburizing alloys

    Science.gov (United States)

    Enloe, Charles M.

    Existing commercial carburizing alloys can be processed at higher temperatures and shorter processing times utilizing vacuum carburizing due to the suppression of intergranular oxidation. To provide resistance to undesired grain coarsening at these elevated temperatures and associated reduction in fatigue performance, microalloyed steel variants have been developed which employ fine Ti- and Nb-carbonitrides to suppress grain growth. Grain coarsening resistance is believed to be limited by the coarsening resistance of the precipitates themselves at high temperature, so further alloy/processing developments to enhance microalloy precipitate coarsening resistance based on a greater mechanistic understanding of solute interaction with microalloy precipitates would be beneficial. Molybdenum is known to affect microalloy precipitate evolution during processing in ferrite and austenite, but a unified explanation of the role of Mo in precipitate evolution is still lacking. Accordingly, the effect of molybdenum on microalloy precipitate size and composition evolutions and the associated onset of abnormal grain growth in austenite was investigated in Mo-bearing and Mo-free, Nb,Ti-microalloyed SAE 4120 steels. Molybdenum additions of 0.30 wt pct to alloys containing Nb additions of 0.05 and 0.10 wt pct Nb delayed the onset of abnormal grain growth in hot-rolled alloys reheated and soaked at 1050 °C and 1100 °C. The coarsening rate of microalloy precipitates was also reduced in Mo-bearing alloys relative to Mo-free alloys during isothermal soaking at 1050 °C, 1100 °C, and 1150 °C. The observed microalloy precipitate coarsening rates exceeded those predicted by the Lifshitz-Slyozov-Wagner relation for volume-diffusion-controlled coarsening, which is attributed to an initial bimodal precipitate size distribution prior to reheating to elevated temperature. Heat-treatments of hot-rolled alloys (tempering and solutionizing) prior to reheating to elevated temperature in

  1. Effect of mass transfer limitations on catalyst performance during reduction and carburization of iron based Fischer-Tropsch synthesis catalysts

    Institute of Scientific and Technical Information of China (English)

    Akbar; Zamaniyan; Yadollah; Mortazavi; Abbas; Ali; Khodadadi; Ali; Nakhaei; Pour

    2013-01-01

    Existence of intraparticle mass transfer limitations under typical Fischer-Tropsch synthesis has been reported previously,but there is no suitable study on the existence of intraparticle diffusion limitations under pretreatment steps (reduction and activation) and their effect on catalytic performance for iron based catalysts.In this study,Fe-Cu-La-SiO2 catalysts were prepared by co-precipitation method.To investigate the intraparticle mass transfer limitation under reduction,activation and reaction steps,and its effect on catalytic performance,catalyst pellets with different sizes of 6,3,1 and 0.5 mm have been prepared.All catalysts were calcined,pretreated and tested under similar conditions.The catalysts were activated in hydrogen (5%H2in N2) at 450℃ for 3 h and exposed to syngas (H2/CO=1) at 270℃ and atmospheric pressure for 40 h.Afterwards,FTS reaction tests were performed for approximately 120 h to reach steady state conditions at 290℃,17 bar and a feed flow (syngas H2/CO=1) rate of 3 L/h (STP).Using small pellets resulted in higher CO conversion,FT reaction rate and C5+ productivity as compared with larger pellets.The small pellets reached steady state conditions just 20 h after starting the reaction.Whereas for larger pellets,CO conversion,FT reaction rate and C5+ productivity increased gradually,and reached steady state and maximum values after 120 h of operation.The results illustrate that mass transfer limitations exist not only for FTS reaction but also for the reduction and carburization steps which lead to various phase formation through catalyst activation.Also the results indicate that some effects of mass transfer limitations in activation step,can be compensated in the reaction step.The results can be used for better design of iron based catalyst to improve the process economy.

  2. Study On the Tribological Behavior of the Arc-added Glow Discharge Plasma Non-hydrogen Carburization On Titanium Alloy Surfaces

    Institute of Scientific and Technical Information of China (English)

    CHEN Fei; ZHAHGYue-fei; Liu Yu; TANG Bin; PAN Jun-de

    2004-01-01

    This paper introduces a new titanium alloys surface strengthening treatment by using the arc-added glow discharge plasmas non-hydrogen carburization technique. High purity and high strength graphite is selected as cooling cathode arc source for supplying carbon atoms and particle, which migrate to the titanium alloy(Ti6Al4V) surface and form modified layer. Thus, the hydrogen embrittlement is avoided while the tribological behavior of the titanium alloy surface is improved in the respects of anti-friction and anti-wear ability. The tribological behavior of the modified layer under dry sliding against SAE52100 steel was evaluated on a ball-on-disc test rig. The results showed that the modified layer obtained a thickness of 30μm at 980℃, 30minutes. The microhardness of the Ti6A14V alloy surface attained 936 HV, which was much larger than that of the Ti6A14V alloy. The Ti6A14V alloy was characterized by adhesion wear and scuffing under dry sliding against the steel, while the surface modified layer experienced much abated adhesion wear and scuffing under the same testing condition. This could be attributed to the carbon element with different modalities exists in the modified layer.The modified layer showed good friction-reducing and fair anti-wear ability in dry sliding against the steel. Using the SEM,XRD and XPS, the phase structure and morphology of the carburization modified layer was analyzed.

  3. Effect of tensile stress on the formation of S-phase during low-temperature plasma carburizing of 316L foil

    Energy Technology Data Exchange (ETDEWEB)

    Li Wei [School of Metallurgy and Materials, University of Birmingham, B15 2TT (United Kingdom); Li Xiaoying, E-mail: X.LI.1@bham.ac.uk [School of Metallurgy and Materials, University of Birmingham, B15 2TT (United Kingdom); Dong Hanshan [School of Metallurgy and Materials, University of Birmingham, B15 2TT (United Kingdom)

    2011-08-15

    Low-temperature plasma carburizing of austenitic stainless steel can produce a carbon-supersaturated austenite layer, the 'S-phase', on the surface, which has high hardness, excellent wear and fatigue properties, and good corrosion resistance. Although the S-phase was discovered some years ago, the basic understanding of S-phase formation remains incomplete. In this paper, the effect of tensile stresses (0-80 MPa) on the formation and stability of S-phase during carburizing of 316L stainless steel foils at 400, 425 and 450 deg. C for 10 h has been investigated for the first time. The microstructures were characterized by X-ray diffraction, scanning electron microscopy and transmission electron microscopy and the mechanical properties were evaluated by microhardness and tensile tests. The results showed that the in situ applied tensile stress effectively thickened S-phase layers. The calculated activation energy for carbon diffusion in 316L was reduced from 142.76 to 133.91 kJ mol{sup -1} when a tensile stress of 40 MPa was applied. However, chromium carbides were formed in the outmost surface when the tensile stress exceeded 40 MPa. The results are discussed and explained through appropriate thermodynamic calculations.

  4. Enhanced Droplet Erosion Resistance of Laser Treated Nano Structured TWAS and Plasma Ion Nitro-Carburized Coatings for High Rating Steam Turbine Components

    Science.gov (United States)

    Pant, B. K.; Arya, Vivek; Mann, B. S.

    2010-09-01

    This article deals with surface modification of twin wire arc sprayed (TWAS) and plasma ion nitro-carburized X10CrNiMoV1222 steel using high power diode laser (HPDL) to overcome water droplet erosion occurring in low pressure steam turbine (LPST) bypass valves and LPST moving blades used in high rating conventional, critical, and super critical thermal power plants. The materials commonly used for high rating steam turbines blading are X10CrNiMoV1222 steel and Ti6Al4V titanium alloy. The HPDL surface treatment on TWAS coated X10CrNiMoV1222 steel as well as on plasma ion nitro-carburized steel has improved water droplet resistance manifolds. This may be due to combination of increased hardness and toughness as well as the formation of fine grained structure due to rapid heating and cooling rates associated with the laser surface treatment. The water droplet erosion test results along with their damage mechanism are reported in this article.

  5. 潜水渣浆泵的设计及应用研究%Study on Testing Method of Carburizing Gears for Heavy Duty Trucks

    Institute of Scientific and Technical Information of China (English)

    张海平; 赵玉刚; 孟祥炎

    2012-01-01

    Driving gears are key components to ensure the running safety of automobiles, and the tests of the mierostrueture properties of gears are the important guarantee of its quality eontrol. Aiming at earburized gears for heavy duty trucks, the paper in detail studied the testing methods and demand of the chemical composition, microstructure, carbide rating, retained austenite and martensite rating, carburizing quenching effectively hardening depth, surface and core hardness. The results can provide a reference basis the design, manufacturing and test of carburizing gears for heavy duty trucks.%渣浆泵是固液混合物管道输送的核心部件,由于设计和材质方面的缺陷,我国目前应用的大部分渣浆泵不同程度存在运行效率较低和使用寿命短的问题。本文设计的潜水式渣浆泵通过采用先进的水力模型、合理选用耐磨材料和加工工艺,其抽渣运行效率大幅度提高、使用寿命也得到延长。

  6. Selection and Application of DT-CA-09 Type Carburant and the Experimental Results Analysis%DT-CA-09型增碳剂的选用及实验分析

    Institute of Scientific and Technical Information of China (English)

    徐桂洪; 张行河

    2011-01-01

    使用中频电炉熔炼合成铸铁,必须采用增碳技术,以保证铁液中碳含量在工艺要求的范围内.在中频电炉熔炼新工艺中,根据增碳剂分类及增碳原理,结合电炉熔炼对增碳剂的要求,选用了国产DT-CA-09型增碳剂.实验证明,所选用增碳剂可满足目前中频电炉熔炼工艺需求.%Melting synthetic cast iron with the medium frequency furnace it is necessary to adopt carburet ion technology to ensure that carbon content of liquid iron is meet the limits of particular foundry technology. According to the classification of carburant and principle of carburetion, combined with the requirements of carburant in electric furnace melting, the domestic DT-CA-09 type carburant was chosen in the new technology of the medium frequency electric furnace melting, and experiments proved that the selected carburant can meet the demands of current electric furnace melting technology.

  7. 金相法测定钢渗碳层的有效硬化层深度%Depth Measurement of Carburized and Available Layer of Steel with Metallographic Method

    Institute of Scientific and Technical Information of China (English)

    伞晶超; 顾园

    2012-01-01

    Through experiment of carburize a set of 20CrMnMo steel samples, comparison between carburized layer of annealing with metallographic method and hardened layer depth with micro hardness basing on the national standard. According to measure result, carburized layer depth is the same to availability hardened layer depth which is set out quenching with metallographic method on annealing equilibrium, then it can be concluded that annealing equilibrium equivalent to the quenching carburized availability hardened layer depth, use metallographic microscope in existence to determine the carburized availability hardened layer.%通过对渗碳钢20CrMnMo试样渗碳后,用金相法检测退火状态的渗碳层与根据国家新标准用显微硬度计测定渗碳有效硬化层深度进行对比.根据测定的结果,用金相法以退火后的平衡组织,在显微镜下测定共析以上的渗层深与用显微硬度计测定的淬火状态的渗碳有效硬化层深基本上是一致的,从而推断可用金相法以退火状态的平衡组织在显微镜下测定共析以上的组织深度等效为渗碳后淬火状态的有效硬化层深度,从而以利用炉前现有设备金相显微镜来进行渗碳有效硬化层的测定.

  8. 基于ANSYS的渗碳齿轮动力学分析%Dynamics Analysis of Carburized Gear Based on ANSYS

    Institute of Scientific and Technical Information of China (English)

    高伟

    2014-01-01

    Setting carburized gear as the research object, considering the traditional computing the stress distribution, and based on ANSYS software platform, this paper does the finite element modeling and dynamic analysis, the result provides a theoretical basis to improve reliability of gear, which is of great significance to ensure the safety of production.%本文以渗碳齿轮为研究对象,针对传统计算无应力分布等情况,以Ansys软件为平台,对其进行了有限元建模,动力学分析,其结果对齿轮提高可靠性提供了理论基础,对保证安全生产有十分重要的意义。

  9. Hydrogen Effect on Coke Removal and Catalytic Performance in Pre-Carburization and Methane Dehydro-Aromatization Reaction on Mo/HZSM-5

    Institute of Scientific and Technical Information of China (English)

    Hongtao Ma; Ryoichi Kojima; Satoshi Kikuchi; Masaru Ichikawa

    2005-01-01

    In this study,the effects of pre-carburization of catalyst,hydrogen addition to methane feed and the space velocity of methane on the catalytic performance in methane to benzene (MTB) reaction were discussed in detail over Mo/HZSM-5 catalyst at 1023 K and 0.3 MPa. Compared with the non-precarburized catalyst,the Mo catalyst pre-carburized under the flow of CH4+4H2 at 973 K was found to have the higher activity and better stability. Further 6% H2 addition to the methane feed suppressed the aromatic type of coke formation effectively,and improved the stability of catalyst markedly,moreover gave a much longer reaction life of catalyst (53 h at 1023 K and 5400 ml/(g·h)) and much more formation amounts of benzene and hydrogen. With increase of methane space velocity,both the naphthalene formation selectivity and the coke formation selectivity were decreased by the shortened contact time;the benzene formation selectivity and total formation amount before the complete deactivation of catalyst were increased ly,while the total naphthalene and coke formation amounts did not change much.At high methane space velocity (≥5400 ml/(g·h)),a new middle temperature coke derived from the high temperature aromatic coke was formed on the catalyst; all the coke formed could be burnt off at lower temperature in oxygen,compared with those obtained at low space velocity. Considering the benzene formation amount and catalyst stability together,5400 ml/(g·h) was proved to be the most efficient methane space velocity for benzene production.

  10. High temperature corrosion of 9Cr-1Mo ferritic steel P91 modified, in oxidizing-carburizing atmospheres; Corrosion a temperatura alta del acero ferritico 9Cr-1Mo modificado P91, en atmosferas simuladas oxidantes-carburantes

    Energy Technology Data Exchange (ETDEWEB)

    Pena-Ballesteros, D. Y.; Vazquez-Quintero, C.; Laverde-Catano, D.; Serna, G.

    2012-11-01

    High temperature corrosion in processing units of the chemical, petrochemical, and thermoelectric carbochemical is of high interest, due to the costs generated by sudden failures caused by deterioration in the mechanical properties of metals, being the carburization of the metallic matrix the most important corrosion mechanism resulting in loss of ductility and creep resistance. In this research a 9Cr-1Mo modified steel P91 was exposed to simulated atmospheres oxidant-fuel gas mixtures simultaneous in equilibrium of CO, CO{sub 2}, CH{sub 4}, H{sub 2}O and H{sub 2}, similar to those produced in the refining industry, at temperatures between 550 and 750 degree centigrade. The microstructural evolution of the metal matrix was analyzed, also the growth, evolution and behavior of oxide layers and carburized, establishing the mechanism of deterioration of the material and the extent of damage for times exceeding 700 h of exposure. (Author) 21 refs.

  11. 高合金钢过饱和固体渗碳的计算机模拟%Computer Simulation of Super-saturated Solid Carburization of High Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    叶健松; 匡琦; 戚正风

    2001-01-01

    The process of super-saturated carburization of high alloy steels was discussed,and the corresponding mathematical model was presented.The carbon profile of carburized layer for 3Cr13 and Cr10 with solid carburization is simulated by computer.The simulation result is basically agreement with the experimental one.This testifies that the mathematical model and method are feasible.%本文讨论了高合金钢过饱和渗碳过程,提出了计算高合金钢固体渗碳的碳浓度分布的数学模型,以此模型对3Cr13和Cr10固体渗碳的碳浓度分布进行了计算机模拟。模拟结果与相应的实验结果基本吻合,表明了本文的数学模型及方法是可行的。

  12. 奥氏体不锈钢低温气体渗碳过程中温度对渗碳层的影响%Effect of temperature on low-temperature gas carburized layer of austenitic stainless steel

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

      利用扫描电镜、电子探针、显微硬度计、CS电化学工作站研究AISI316奥氏体不锈钢经低温气体渗碳处理后渗碳层显微组织及力学特性的变化。结果表明,在450,470,500℃温度条件下,在AISI316奥氏体不锈钢表面获得10~33μm的硬化层,随温度的不同,渗层深度、硬度梯度、耐蚀性能呈现不同的变化规律。%Microstructure and mechanical properties of low⁃temperature gas carburized layer of AISI316 austenitic stainless steel were investigated by means of scanning electron microscopy(SEM),micro hardness tester,CS electrochemical workstation. The experimental results indicate that the thickness of hardened layer is within the range of 10 to 33 μm,when AISI316 austenitic stainless steel is carburized at 450,470,500 ℃. With the variation of carburizing temperature,different case depth,hardness gradient and corrosion resistance are observed in the steel.

  13. 铝氮比对轿车用渗碳钢晶粒混晶的影响%INFLUENCE OF ALUMINUM-NITROGEN RATE ON MIXEDG RAIN STRU CTURE OF20 MnCr 5 CARBURIZING STEEL FOR CAR

    Institute of Scientific and Technical Information of China (English)

    齐建军; 李绍杰

    2015-01-01

    在转炉长流程生产工艺条件下,研究了铝含量、氮含量和铝氮比对轿车用20MnCr5渗碳钢晶粒度混晶的影响。结果表明,在规定的热处理工艺条件下,20MnCr5渗碳齿轮钢产生混晶的主要原因是钢中氮含量偏低。当20MnCr5钢中铝含量≥00.25%且铝氮比≥3时,可以达到轿车渗碳钢对奥氏体晶粒度的要求。%It is researched the influence of contents of aluminum and nitrogen and their proportion on mixed grain size of 20MnCr5 carburizing steel for cars in long process of converter.The result shows that under the specified heat treatment process, the main reason for mixed grain in 20MnCr5 carburizing gear steel is too low nitrogen content in steel.The demand of car carburizing steel for austenite brain size can be met if the a-luminum content not being lower than 0.025%and aluminum-nitrogen proportoi n notb eing smallert han 3.

  14. 重型汽车用渗碳齿轮检验方法的分析研究%Study on Testing Method of Carburizing Gears for Heavy Duty Trucks

    Institute of Scientific and Technical Information of China (English)

    张红梅; 郝爽; 孟丽

    2012-01-01

    变速器和车桥等部件中的传动齿轮是保证汽车行驶安全的核心部件,齿轮的组织性能的检验是其质量控制的重要保证。本文就重型汽车渗碳齿轮的化学成分、金相组织、碳化物评级、残余奥氏体和马氏体评级、渗碳淬火有效硬化层深、表面和心部硬度等检验方法和要求进行了详细的研究分析,可为重型汽车用渗碳齿轮的设计、制造及检验提供参考依据。%Driving gears are key components to ensure the running safety of automobiles, and the tests of the mierostrueture properties of gears are the important guarantee of its quality eontrol. Aiming at carburized gears for heavy duty trucks, the paper in detail studied the testing methods and demand of the chemical composition, mierostrueture, carbide rating, retained anstenite and martensite rating, carburizing quenching effectively hardening depth, surface and core hardness. The results can provide a reference basis the design, manufacturing and test of carburizing gears for heavy duty trucks.

  15. In-service testing of Ni{sub 3}Al coupons and trays in carburizing furnaces at Delphi Saginaw. CRADA final report

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.; Santella, M.L.; Viswanathan, S.; Swindeman, R.W. [Oak Ridge National Lab., TN (United States); Chatterjee, M. [General Motors Corporaion, Saginaw Division (United States)

    1998-08-01

    This Cooperative Research and Development Agreement (CRADA) report deals with the development of nickel aluminide alloy for improved longer life heat-resistant fixture assemblies for batch and continuous pusher carburizing furnaces. The nickel aluminide development was compared in both coupon and component testing with the currently used Fe-Ni-Cr heat-resisting alloy known as HU. The specific goals of the CRADA were: (1) casting process development, (2) characterization and possible modification of the alloy composition to optimize its manufacturing ability and performance under typical furnace operating conditions, and (3) testing and evaluation of specimens and prototype fixtures. In support of the CRADA objectives, coupons of nickel aluminide and the HU alloy were installed in both batch and pusher furnaces. The coupons were taken from two silicon levels and contained welds made with two different filler compositions (IC-221LA and IC-221W). Both nickel-aluminide and HU coupons were removed from the batch and pusher carburizing furnace at time intervals ranging from one month to one year. The exposed coupons were cut and mounted for metallographic, hardness, and microprobe analysis. The results of the microstructural analysis have been transmitted to General Motors Corporation, Saginaw Division (Delphi Saginaw) through reports that were presented at periodic CRADA review meetings. Based on coupon testing and verification of the coupon results with the testing of trays, Delphi Saginaw moved forward with the use of six additional trays in a batch furnace and two assemblies in a pusher furnace. Fifty percent of the trays and fixtures are in the as-cast condition and the remaining trays and fixtures are in the preoxidized condition. The successful operating experience of two assemblies in the pusher furnace for nearly a year formed the basis for a production run of 63 more assemblies. The production run required melting of 94 heats weighing 500 lb. each. Twenty

  16. Rational Formulation of Alternative Fuels using QSPR Methods: Application to Jet Fuels Développement d’un outil d’aide à la formulation des carburants alternatifs utilisant des méthodes QSPR (Quantitative Structure Property Relationship: application aux carburéacteurs

    Directory of Open Access Journals (Sweden)

    Saldana D.A.

    2013-06-01

    from the literature, from experimental measurements and from molecular simulations for complex molecules. The interest of such models in the selection of molecules can be shown for example by the trade-off between cold flow properties and density of paraffinic compounds. If the carbon chain length is too high, the cold flow properties are compromised. One solution can be to increase branching or incorporate fuel base with good cold flow properties such as naphthenic or aromatic compounds. However, this leads to a decrease in density below the jet fuel specification. Again, using naphthenic of alkyl-aromatic compounds produced from biomass can help. Le développement des carburants alternatifs est en plein essor, notamment dans le domaine aéronautique. Cela se concrétise par la possibilité d’incorporer jusqu’à 50 % de carburants de synthèse de type Fischer- Tropsch (FT ou hydroprocessed esters and fatty acids (HEFA dans du carburéacteur. De même, ces carburants paraffiniques se développent pour le transport terrestre en parallèle des biocarburants à base d’esters ou d’alcool actuellement disponibles. La formulation de ces carburants alternatifs est actuellement basée sur une sélection des produits via des critères physiques. L’atteinte de ces critères se fait souvent par des formulations empiriques et ce type de fonctionnement ne s’avère pas très efficace et montre ses limites. En effet, les carburants alternatifs présentent des propriétés chimiques qui peuvent être différentes en fonction du procédé (répartition n-paraffines/iso-paraffines, longueur de chaîne, ramification, etc. et donc modulable. Ainsi, une nouvelle voie pourrait être envisagée visant à déterminer par le calcul, la molécule (ou le mélange de molécules la plus à même de répondre au cahier des charges du carburant, puis à étudier ou à optimiser les voies de synthèse permettant d’accéder à ces produits. Le travail présenté a pour objectif le d

  17. Thermochemical Conversion of Lignin for Fuels and Chemicals: A Review Conversion thermochimique de la lignine en carburants et produits chimiques : une revue

    Directory of Open Access Journals (Sweden)

    Joffres B.

    2013-10-01

    Full Text Available Lignin is one of the biomass components potentially usable as renewable resource to produce fuels or chemicals. After separation from the lignocellulosic matrix, this macromolecule is nowadays essentially valorized by combustion in paper mills. If second generation ethanol is produced in the future from lignocellulosic biomass, some increasing reserves of lignin will be available in addition to the ones coming from the paper industry. The main thermochemical ways such as pyrolysis, solvolysis, hydrothermal conversion and hydroconversion considered for the valorization of the lignin are reviewed in this article. La lignine est une des composantes de la biomasse lignocellulosique potentiellement valorisable comme ressource renouvelable pour la production de carburants ou de produits chimiques. Après séparation de la matrice lignocellulosique, cette macromolécule est de nos jours essentiellement utilisée comme combustible dans l’industrie papetière. Outre cette filière papetière, la production d’éthanol de seconde génération à partir de la cellulose aura comme conséquence la mise à disponibilité d’encore plus grandes quantités de lignine. De nouvelles applications pourront donc être proposées pour l’utilisation de cette bio-ressource. Les différentes voies thermochimiques : pyrolyse, solvolyse, conversion hydrothermale et hydroconversion envisagées pour la valorisation de la lignine sont décrites dans cet article.

  18. Dosage direct des alcools et éthers dans les carburants par chromatographie en phase liquide Direct Measurement of Alcohols and Ethers in Gasohols by Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Petroff N.

    2006-11-01

    Full Text Available Les différents composés oxygénés potentiels des carburants (alcools jusqu'aux butanols, acétone et éthers en C5 et C6 sont dosés par chromatographie en phase liquide inversée, avec deux qualités d'éluant sur la même colonne (RP 18. L'analyse est faite à 50 °C, avec un détecteur réfractométrique. La limite de sensibilité peut atteindre 100 ppm pour les alcools. The different potential oxygenated compounds in gasolines blended with alcohols up to butanols, acetone and ethers with 5 and 6 carbons are measured by reverse-phase liquid chromatography with two elution systems in the same column (RP 18. Analysis is performed at 50°C with a refractometer as detector. The sensitivity limit can reach 100 ppm for alcohols.

  19. 低碳中铬钢渗碳层的耐磨粒磨损性能研究%Study on Abrasive Wear-Resistance of Carburized Low-carbon Medium-chromium Steel

    Institute of Scientific and Technical Information of China (English)

    张黔; 孙小华; 李朝志

    2001-01-01

    The microstructure and abrasive wear-resistence of carburized layer of low-carbon medium-chromiun steel.compered with cemented 20 steel and Cr12Mo1V steel,was investigated.Carburized layer of 1Cr6Si2Mo steel contains large number of fine carbide(2.5~3.0 μm),which size smaller than that one of Cr12Mo1V.The wear-resistence of 1Cr6Si2Mo steel after carburizing and queching is obviously better than that of 20 steel.but less than that of Cr12Mo1V steel by vacuum heat treatment.%对低碳中铬钢(1Cr6Si2Mo)固体法稀土渗碳层的组织和耐磨性能与渗碳20钢及淬火Cr12Mo1V钢进行了对比试验研究。1Cr6Si2Mo钢的渗碳层内含有大量粒度为2.5~3.0 μm、弥散分布的铬碳化物,其尺寸比Cr12Mo1V钢中的共晶碳化物小。渗碳淬火后的1Cr6Si2Mo钢试样耐磨粒磨损性能大大优于渗碳淬火后的20钢,但不及真空热处理的Cr12Mo1V。

  20. L'auto adaptation à des mélanges essence/alcool utilisés comme carburant automobile: le moteur souple The Self-Adapting of Gasoline/Alcohol Mixtures Used As Automotive Fuel: the Flexible Engine

    Directory of Open Access Journals (Sweden)

    Dorbon M.

    2006-11-01

    Full Text Available Le moteur souple est un moteur susceptible d'être alimenté par des carburants constitués de mélanges d'une essence classique et d'un alcool léger (méthanol ou éthanol; si la concentration de chacun des composants de ces mélanges varie, les réglages nécessaires au bon fonctionnement du véhicule se font automatiquement. Dans cet article, sont tout d'abord exposées les propriétés caractéristiques en tant que carburant automobile de l'un de ces alcools légers, le méthanol. Puis viennent les descriptions des dispositifs qui font le moteur souple c'est-à-dire d'une part les systèmes de reconnaissance du carburant et d'autre part les appareillages susceptibles de modifier les réglages du moteur (alimentation et allumage en fonction de la qualité du mélange consommé. A flexible engine is one capable of running on fuels consisting of mixtures of conventional gasoline and a light alcohol (methanol or ethanol. If the concentration of each of these components of such mixtures varies, the tuning required for the proper running of the vehicle takes place automatically. This article begins by describing the characteristic properties of one of these light alcohols (methanol as an automotive fuel. Then the equipment is described that makes an engine flexible, i. e. both the fuel recognition systems and the equipment capable of changing engine tuning (feed and ignition as a function of the quality of the mixture burned.

  1. Evaluation des performances du transistor MOS de puissance sur carbure de silicium. Compromis résistance passante, tenue en tension et vitesse de commutation

    Science.gov (United States)

    Beydoun, B.; Rossel, P.; Tranduc, H.; Charitat, G.

    1994-08-01

    The DC trade-off " ON resistance versus voltage capability " is determined for the SiC multicellular Power MOSFET transistor. First, this limit is analytically calculated for the bulk material. Then, the influence of the size of the MOSFET cell is considered. Under dynamic condition, the switching behaviour is simulated and analysed. We confirm that the DC performances of the SiC device are better than those of Si structures. From a dynamic point of view, a degradation can or not occur depending upon the voltage capability of the considered device. The degradation is due to the drain-gate Miller capacitance increase with the drain doping value. On détermine le compromis statique "résistance passante — tenue en tension" des transistors MOS de puissance multicellulaires sur carbure de silicium. Cette limite est d'abord calculée analytiquement pour le matériau volumique. L'influence de la taille des cellules du transistor MOS est ensuite prise en compte. Au niveau dynamique, la commutation résistive est également simulée. On confirme que les performances statiques de composants SiC sont potentiellement meilleures que celles de leurs homologues Si. D'un point de vue dynamique, on montre que selon la tenue en tension considérée, une dégradation du temps de commutation peut ou non apparaître. Celle-ci est expliquée par l'accroissement de la capacité drain-grille corrélative à l'augmentation de dopage.

  2. 1Cr11Ni2W2MoV钢渗碳层中孪晶组织形成原因及对性能的影响%Twin forming reason in carburized layer and its effect on mechanical properties of 1Cr11Ni2W2MoV steel

    Institute of Scientific and Technical Information of China (English)

    刘松

    2011-01-01

    Twin forming reason in carburized layer of 1Cr11Ni2W2MoV steel and its effect on the mechanical properties were investigated with microstructure observation,fracture examination,micro hardness test and EDS analysis.The results show that the twin forming reason is related with the lower carbon potential and higher carburizing temperature.The twin existing in carburized layer changes the fracture mode and results in the brittleness increase, and it should be regarded as defect in carburized layer of 1Cr11Ni2W2MoV steel.%采用显微组织观察、断口形貌分析、显微硬度测试和能谱分析,对1Cr11Ni2W2MoV钢渗碳层中孪晶组织形成原因及其对性能的影响进行了研究.结果表明,1Cr11Ni2W2MoV钢渗碳层中出现孪晶的原因可能与渗碳时工件周围碳势较低,且渗碳温度较高有关;渗碳层中孪晶组织的存在,使其断裂模式发生改变,脆性增加,应视为缺陷组织.

  3. The influence of surface microstructure and chemical composition on corrosion behaviour in fuel-grade bio-ethanol of low-alloy steel modified by plasma nitro-carburizing and post-oxidizing

    Science.gov (United States)

    Boniatti, Rosiana; Bandeira, Aline L.; Crespi, Ângela E.; Aguzzoli, Cesar; Baumvol, Israel J. R.; Figueroa, Carlos A.

    2013-09-01

    The interaction of bio-ethanol on steel surfaces modified by plasma-assisted diffusion technologies is studied for the first time. The influence of surface microstructure and chemical composition on corrosion behaviour of AISI 4140 low-alloy steel in fuel-grade bio-ethanol was investigated. The steel surfaces were modified by plasma nitro-carburizing followed plasma oxidizing. X-ray diffraction, scanning electron microscopy, optical microscopy, X-ray dispersive spectroscopy, and glow-discharge optical emission spectroscopy were used to characterize the modified surface before and after immersion tests in bio-ethanol up to 77 days. The main corrosion mechanism is pit formation. The pit density and pit size were measured in order to quantify the corrosion resistance which was found to depend more strongly on microstructure and morphology of the oxide layer than on its thickness. The best corrosion protection was observed for samples post-oxidized at 480 °C and 90 min.

  4. Fuel Penalty Comparison for (Electrically Heated Catalyst Technology Comparaison de l’augmentation de consommation de carburant pour la technologie de catalyseurs chauffés à l’électricité

    Directory of Open Access Journals (Sweden)

    Kessels J. T.B.A.

    2010-03-01

    Full Text Available The conversion efficiency of three way catalytic converters is mainly defined by the temperature range wherein they are operating. Traditionally, ignition retard has been used to reduce the light-off time of the catalyst. This is however associated with a fuel penalty. With increasing vehicle electrification, electrically heating facilities present an alternative, especially for hybrid vehicles. Nevertheless, system complexity of hybrid vehicles prevents engineers to evaluate possible heating technologies and their corresponding fuel penalty with respect to traditional solutions. This paper evaluates the application of an electrically heated catalyst on a hybrid vehicle equipped with a Natural Gas (NG engine. The effect of heating power on light-off time and fuel penalty is determined, using analysis techniques emerging from integrated powertrain control. By means of a case study, the importance of an integral approach is explained by comparing the fuel penalty and conversion efficiency improvement of electric heating with that of ignition retard. In this process, a mix of simulation and test data were combined, forming the foundations for future control developments of a suitable light-off strategy. L’efficacité de conversion des catalyseurs est principalement définie par la gamme de température dans laquelle ils fonctionnent. Un retard du point d’allumage a traditionnellement été utilisé pour réduire le temps d’amorçage du catalyseur. Ceci est cependant associé à une augmentation de la consommation de carburant. Avec l’électrification des véhicules, la possibilité de chauffage électrique représente véritablement une alternative, tout particulièrement pour les véhicules hybrides. Cependant, la complexité des véhicules hybrides rend difficile l’évaluation des technologies de chauffage éventuelles ainsi que l’augmentation de la consommation de carburant associée ; il est aussi difficile de comparer ces r

  5. Friction and wear properties of double glow plasma carburized layer of Ti2AlNb base O phase alloy%Ti2AlNb基O相合金双辉等离子渗碳层摩擦磨损性能

    Institute of Scientific and Technical Information of China (English)

    杨晶晶; 缪强; 梁文萍; 李龙; 任蓓蕾; 朱丹阳

    2013-01-01

    Double glow plasma carburized layer was carried out on the surface of Ti2AlNb base O phase alloy to improve its wear-resistance.The microstructure,element distribution,phases,hardness and wear resistance of the carburized layer were analyzed by SEM,EDS,XRD,hardness tester and friction wear testing machine.The results show that a carburized layer is formed about 30 μn,and surface hardness of the carburized layer is 1053-V0.1 and it gradually decreases along the depth.The general friction coefficient of the carhnrized layer and matrix is 0.4 and 0.75,respectively.The specific wear rate of carburized layer is 1/17 of the matrix.The wear resistance of Ti2AlNb base O phase alloy is improved significantly by plasma carburizing.%利用双层辉光等离子表面合金化技术在Ti2AlNb基O相合金表面进行渗碳处理,采用SEM、EDS、XRD、硬度仪及摩擦磨损试验机对其组织成分、元素分布、相组成、硬度及耐磨性能进行研究.结果表明,在Ti2AlNb基O相合金表面形成了约30μm的渗碳层,渗碳层表面硬度为1053 HV0.1,且硬度随渗层厚度梯度递减.渗碳层和基体平均摩擦因数分别为0.4和0.75,渗碳层比磨损率为基体比磨损率的1/17.双层辉光等离子渗碳技术明显提高了Ti2A1Nb基O相合金的耐磨性.

  6. 12CrNi3A凸轮轴渗碳激光强化复合处理工艺%The Intensification and Recombination Treatment of Carburization Laser of Cam Shaft 12CrNi3A

    Institute of Scientific and Technical Information of China (English)

    胡佳英

    2001-01-01

    he technique for the intensification and recombination treatment of carburization laser of cam shaft 12CrNi3A have been studied in this paper.The tests results show that,with using the carburization technique to increase the carbon density of surface and through the reasonable and effective technology of laser quenching treatment an ideal and uniform harden quench surfaceis obtained.The hardness of surface has been strengthened.The wear resistance and fatigue strength resistance of cam shaft has been enhanced.The problem of abrasive failure of cam shaft has also been resolved. It is a new attempt to develop and apply the technology of laser surface heat treating.%对12CrNi3A凸轮轴渗碳激光强化复合处理进行了研究。研究结果表明,采取表面渗碳工艺增加表层的碳浓度,并通过采用合理有效的激光淬火处理工艺,获得理想的淬硬层分布,提高了表层的硬度,增强了凸轮轴表面的耐磨性和抗疲劳强度,解决了凸轮轴磨损失效问题,是开发和应用激光表面热处理技术的一个新的尝试。

  7. 20CrMnMo钢渗碳齿轮磨削裂纹成因分析%Causes Analysis on Grinding Cracks of 20CrMnMo Steel Carburized Gears

    Institute of Scientific and Technical Information of China (English)

    孙胜伟; 宋亚虎; 刘铁山; 史向阳; 赵学谦

    2016-01-01

    采用化学成分分析、金相分析、显微硬度测试以及残余应力测定等方法对某 2 0 CrMnMo钢渗碳齿轮磨削裂纹产生原因进行了分析.结果表明:该齿轮产生磨削裂纹主要是由于磨削过程中表面产生严重的二次淬火烧伤和回火烧伤,二次淬火烧伤的次表面及边缘回火烧伤区硬度大幅下降及表面受拉应力,两者共同作用下产生了磨削裂纹;另外,渗碳层中存在针状马氏体和大量残余奥氏体,增加了齿轮磨削开裂的敏感性,这是齿轮产生磨削裂纹的另一个重要原因.%The forming reasons for grinding cracks of 20CrMnMo steel carburized gears were analyzed by means of chemical composition analysis,metallographic examination,microhardness test and residual stress test. The results show that the main reasons for the grinding cracks were secondary quenching burn and tempering burn on the gear surface during grinding.Grinding cracks were caused by the combined effects of serious decline in hardness and surface tensile stress at the subsurface of the secondary quenching burn area and the edge tempering burn area.Besides,the grinding cracking sensitivity was increased due to the acicular martensite and massive retained austenite existing in the carburized layer,which was also an important reason for the grinding cracks.

  8. Enhanced wear and fatigue properties of Ti-6Al-4V alloy modified by plasma carburizing/CrN coating%通过等离子渗碳/CrN覆层改性处理提高Ti-6Al-4V合金的耐磨性和抗疲劳特性

    Institute of Scientific and Technical Information of China (English)

    魏明镛

    2005-01-01

    In this study, a newly developed duplex coating method incorporating plasma carburization and CrN coating was applied to Ti-6Al-4V and its effects on the wear resistance and fatigue life were investigated. The carburized layer with approximately150 μm in depth and CrN coating film with 7.5μm in thickness were formed after duplex coating. Hard carbide particles such as TiC And V4 C3 were formed in the carburized layer. XRD diffraction pattern analysis revealed that CrN film had predominant [111] and [200] textures. The hardness (Hv) was significantly improved up to about 1960 after duplex coating while the hardness value of original Ti-6Al-4V was 402. The threshold load for the modification and/or failure of CrN coating was measured to be 32 N using the acoustic emission technique. The wear resistance and fatigue life of duplex coated Ti-6Al-4V improved significantly compared to those of un-treated specimen. The enhanced wear resistance can be attributed to the excellent adhesion and improved hardness of CrN coating film for the duplex coated Ti-6Al-4V. The initiation of fatigue cracks is likely to be retarded by the presence of hard and strong layers on the surface, resulting in the enhanced fatigue life.

  9. 缩短渗碳周期与强烈淬火相结合的节能热处理技术%Energy Savings Using a Combination of Carburizing Cycle Reduction and Intensive Quenching

    Institute of Scientific and Technical Information of China (English)

    Lauralice C. F. Canale; Eduardo Merheb; Jo(a)o C. Vendramim; George E. Totten

    2007-01-01

    在热处理行业,人们一直在探索降低生产成本、节约能源和减少环境污染的方法.汽车制造业在这方面将是大有作为的,其中包括:大幅度缩短渗碳时间,以节能和降低生产成本;开发新型淬火剂替代易燃、有毒的矿物油基淬火剂.采用非易燃的对环境友好的水基淬火剂进行强烈淬火(IQ)是达到这些目标的途径之一.此外,IQ还能使渗碳的扩散时间缩短50%或更多.本文论述了巴西圣保罗大学、巴西Combustol公司以及美国强烈淬火公司合作进行的采用一种强烈淬火工艺成功达到上述目标的研究成果.从长远看,这些成果对热处理工业将具有重要意义.%There is an ongoing interest in the heat treatment industry to identify methods of reducing production cost, energy consumption and to reduce environmental impact of heat treatment practices and materials. Automobile industry offers a number of opportunities in this regard including: reduction of substantial carburizing times which would result in substantial energy savings and reduction in production costs due to shorter processing times and the potential replacement of flammable and relatively toxic petroleum-based quenchants. One way of achieving these goals is to use intensive quenching processes (IQ) which utilize non-flammable and environmentally benign aqueous-based quenchants. Furthermore, IQ offers the potential of significantly reducing total carburizing diffusion times by 50%, or more. This paper will discuss the results of a collaborative study conducted by the University of Sao Paulo at Sao Carlos, Combustol, and Intensive Quenching Technologies to utilize an IQ process to successfully achieve the afore mentioned goals. These results are potentially of major importance to the heat treatment industry.

  10. 耐热钢HP40Nb的中温粉末法渗铝及其抗渗碳特性%Pack aluminizing at moderate temperature on HP40Nb heat-resistant steel and its anti-carburization behaviour

    Institute of Scientific and Technical Information of China (English)

    潘建伟; 谢飞; 孙力; 焦世辉; 翟建祥

    2012-01-01

    Pack aluminizing at temperature of 800-900 ℃ was investigated on HP40Nb heat-resistant steel with a media composed of master alloy of Fe-Al powder as Al supplier,NH4Cl as activator and SiC as filler.The anti-carburizing behaviour of the treated specimen was studied by employing an intensified pack carburization test.The results show that the aluminizing case has high surface quality and adheres very well with the substrate.The case is mainly composed of a deposition zone and a following transition zone.The thickness of the case is thinner than that by higher temperature aluminizing.Direct current field has few influence on the types of phase structure of the aluminized cases,while it can enhance the aluminizing rate at 800 ℃ by nearly 7 times.The aluminized cases studied show excellent anti-carburization ability in the intensified carburization test at 1000 ℃.%以铝铁为供铝剂、氯化氨为活化剂、碳化硅为填充剂,研究了耐热钢HP40Nb在800~900℃间的粉末法渗铝特性,采用固体强化渗碳方式来研究不同状态试样的抗渗碳能力。研究表明:渗层表面质量很高,渗层与基体结合良好,渗层主要由沉积区和过渡区两部分组成,较之高温渗铝,渗层厚度较薄;采用直流电场增强法对HP40Nb粉末法渗铝渗层相组成种类影响不大,但能使其800℃时的渗铝速度提高近7倍。所试验渗铝层在1000℃强化渗碳条件下表现出优良的抗渗碳特性。

  11. Le marché des composés oxygénés dans le secteur des carburants The Market for Oxygen Compounds in the Fuel Sector

    Directory of Open Access Journals (Sweden)

    Meyer C.

    2006-11-01

    Full Text Available Le marché mondial des composés oxygénés, utilisés en mélange avec les carburants comme promoteurs d'octane, présente une expansion importante. On constate que le développement de ce marché se fait par les éthers aux dépens des alcools. Toutefois, la demande de méthanol reste soutenue, du fait que c'est une des matières premières de la synthèse du MTBE. On observe parallèlement des fluctuations importantes de la valorisation de ces composés qui, après avoir atteint en 1988 et début 1989 des niveaux jamais observés jusqu'alors, est revenue ensuite à des valeurs plus habituelles. Peut-on estimer comment ces tendances vont évoluer dans l'avenir ? C'est ce qui va être examiné dans les pages qui suivent. The world market for oxygen compounds used in a blend with fuels as octane promoters has been expanding rapidly in the last two years. This market has been growing via ethers at the expense of alcohols. However, the demand for methanol continues because it is one of the raw materials for MTBE synthesis. At the same time, the upgrading of these compounds has been increasing and has reached its highest level ever. Will these trends continue in the future? This is the topic dealt with by this article.

  12. A Comprehensive Numerical Study on Effects of Natural Gas Composition on the Operation of an HCCI Engine Une étude numérique complète sur les effets de la composition du gaz naturel carburant sur le réglage d’un moteur HCCI

    Directory of Open Access Journals (Sweden)

    Jahanian O.

    2011-11-01

    Full Text Available Homogeneous Charge Compression Ignition (HCCI engine is a promising idea to reduce fuel consumption and engine emissions. Natural Gas (NG, usually referred as clean fuel, is an appropriate choice for HCCI engines due to its suitable capability of making homogenous mixture with air. However, varying composition of Natural Gas strongly affects the auto-ignition characteristics of in-cylinder mixture and the performance of the HCCI engine. This paper has focused on the influence of Natural Gas composition on engine operation in HCCI mode. Six different compositions of Natural Gas (including pure methane have been considered to study the engine performance via a thermo-kinetic zero-dimensional model. The simulation code covers the detailed chemical kinetics of Natural Gas combustion, which includes Zeldovich extended mechanism to evaluate NOx emission. Validations have been made using experimental data from other works to ensure the accuracy needed for comparison study. The equivalence ratio and the compression ratio are held constant but the engine speed and mixture initial temperature are changed for comparison study. Results show that the peak value of pressure/temperature of in-cylinder mixture is dependent of fuel Wobbe number. Furthermore, engine gross indicated power is linearly related to fuel Wobbe number. Gross indicated work, gross mean effective pressure, and NOx are the other parameters utilized to compare the performance of engine using different fuel compositions. Le moteur HCCI (Homogeneous Charge Compression Ignition, ou à allumage par compression d’une charge homogène est une idée prometteuse pour réduire la consommation de carburant et les émissions polluantes. Le gaz naturel, considéré généralement comme un carburant propre, est un choix approprié pour les moteurs HCCI en raison de sa capacité à former avec l’air un mélange homogène. Cependant, la composition du gaz naturel influe fortement sur les caract

  13. 3d Simulation of Di Diesel Combustion and Pollutant Formation Using a Two-Component Reference Fuel Simulation 3D de la combustion et de la formation des polluants dans un moteur Diesel à injection directe en utilisant un carburant de référence à deux composants

    Directory of Open Access Journals (Sweden)

    Barths H.

    2006-12-01

    reference fuels. The contributions of the different reaction paths (thermal, prompt, nitrous, and reburn to the NO formation are shown. Finally, the importance of the mixing process for the prediction of soot emissions is discussed. En séparant calculs aérodynamiques et calculs chimiques, le modèle instationnaire de flamelet permet d'introduire des mécanismes chimiques complets qui comprennent plusieurs centaines de réactions. Ceci est indispensable pour décrire les différents processus qui ont lieu dans un moteur Diesel à injection directe (ID tels que l'auto-inflammation, la fin de la phase de prémélange partiel, la transition vers une combustion diffusive et la formation de polluants tels que les NOx et les suies. Il n'est pas nécessaire de simplifier les taux de réactions hautement non linéaires, d'autre part, la structure complète du processus de combustion est conservée. En utilisant le modèle de type Representative Interaction Flamelet (RIF, l'ensemble monodimensionnel instationnaire d'équations différentielles aux dérivées partielles est résolu en interaction avec le code CFD 3D. La solution ainsi obtenue est couplée avec les flux gazeux et le champ de mélange par l'intermédiaire de plusieurs paramètres dépendant du temps (l'enthalpie, la pression, le taux scalaire de dissipation. En retour, le modèle de flamelet fournit les concentrations moyennes des espèces chimiques, qui sont ensuite exploitées par le code CFD 3D pour calculer les champs de températures et les densités. La densité est nécessaire au code CFD 3D pour déterminer les flux turbulents et le champ de mélange. La formation des polluants est déterminée expérimentalement dans un moteur Diesel Volkswagen DI 1900. Le moteur est alimenté avec du gazole et deux carburants de référence. Un des carburants de référence est du n-décane pur. Le second est un carburant bicomposant formé de 70 % (du volume liquide de n-décane et de 30 % d'alpha-méthylnaphtalène (Idea

  14. Utilisation des huiles végétales et de leurs produits de transestérification comme carburants Diesel Use of Vegetable Oils and Their Transesterification Products As Diesel Fuels

    Directory of Open Access Journals (Sweden)

    Gateau P.

    2006-11-01

    Full Text Available L'utilisation d'huiles végétales et de leurs dérivés comme carburants Diesel a fait l'objet, depuis 1981, de plusieurs études financées par l'Agence Française pour la Maîtrise de l'Energie (AFME et réalisées par l'institut Français du Pétrole (lFP en collaboration avec Elf Renault, le Centre d'Etudes et d'Expérimentation du Machinisme Agricole Tropical (CEEMAT et l'institut de Recherches pour les Huiles et Oléagineux (IRHO. Ce document rassemble les résultats obtenus au banc d'essai sur plusieurs types de moteurs représentant un assez large éventail d'applications, depuis le motoculteur utilisé en agriculture africaine jusqu'au moteur classique de tracteur ou de camion. Deux types de produits ont été examinés : les huiles végétales elles-mêmes employées pures ou en mélange au gazole, et les esters méthyliques de ces huiles utilisés tels quels. Lors d'un fonctionnement de courte durée les huiles aussi bien que les esters conduisent globalement à un fonctionnement satisfaisant du moteur; les pertes de performances par rapport au gazole restent modérées voire imperceptibles. Les seuls problèmes dans ce cas concernent la mise en oeuvre, difficile avec les huiles en raison de leur très forte viscosité, beaucoup plus aisée avec les esters. En endurance, l'inconvénient majeur des huiles végétales et de leurs dérivés concerne la formation de dépôts au nez des injecteurs. Sur les moteurs rustiques à préchambre (type Hatz ce phénomène reste limité puisqu'il a été possible de conduire, sans incident, un ensemble d'essais d'endurance de 1100 h avec différents types d'huiles pures (arachide, coton, palme. Sur les moteurs à Injection directe la formation de dépôts constitue une très sérieuse contrainte puisqu'elle conduit pratiquement à proscrire l'utilisation d'huiles même en mélange (25 ou 50 % dans le gazole. Les esters peuvent alors être proposés à condition qu'un certain nombre de pr

  15. 奥氏体不锈钢低温渗碳硬化处理后的化学亮化处理%Chemical Brightening Treatment of Austenitic Stainless Steel after Low-temperature Plasma Carburizing

    Institute of Scientific and Technical Information of China (English)

    王扬亚; 赵程

    2016-01-01

    目的 研究一种化学方法对经过低温离子渗碳后的奥氏体不锈钢表面进行亮化处理. 方法 采用酸洗(草酸180~200 g/L,硫脲10~15 g/L,OP-10 10~15 mL/L,温度为70 ℃,时间为3 min)、除积炭(邻二氯苯610 g/L,水30 g/L,氢氧化钠20 g/L,油酸100 g/L,甲酚240 g/L,处理温度为70 ℃,在超声波中清洗120 min)、碱洗(氢氧化钠110 g/L,碳酸钠110 g/L,高锰酸钾50 g/L,溶液温度为70℃,在超声波中清洗30 min.)、再酸洗(草酸180~200 g/L,硫脲10~15 g/L,OP-10 10~15 mL/L,溶液温度为70 ℃,在超声波中清洗1 min)的化学处理过程,对低温离子渗碳硬化处理后的316 L奥氏体不锈钢表面进行亮化处理,并对亮化处理前后硬化层的组织结构、厚度、硬度及耐蚀性能进行比较. 结果 硬化处理后的不锈钢经过化学亮化处理过程,就可以比较彻底地去除硬化层表面的黑膜,恢复不锈钢的本色. 结论 化学表面亮化处理后,不锈钢渗硬化层的损失量比较小,去除黑膜后的不锈钢表面表现出很好的耐蚀性能.%Objective To study the method of chemical brightening treatment for austenitic stainless steel after low-temperature plasma carburizing. Methods This paper adopted chemical treatment method to brighten the surface of the carburized 316L austen-ite stainless steel. The chemical treatments included acid-washing(180~200 g/L of oxalic acid,10~15 g/L of thiourea, 10~15 mL/L of OP-10,the temperature was 70 ℃, the time was 3 minutes), removing accumulated carbon (610 g/L of orthodichlorobe-zene,30 g/L of water,20 g/L of sodium hydroxide,100 g/L of oleic acid, 240 g/L of cresol, the temperature was 70℃, ultrosonic cleaning for 120 minutes), alkali-washing (110 g/L of sodium hydroxide,110 g/L of sodium carbonate,50 g/L of potassium per-manganate, the temperature was 70 ℃, ultrosonic cleaning for 30 minutes) and acid-washing (180~200 g/L of oxalic acid,10~15 g/L of thiourea, 10~15 mL/L of OP-10, the temperature was

  16. D’une problématique locale-frontalière à un enjeu binational : le cas de la contrebande transfrontalière de carburants entre la Colombie et le Venezuela

    Directory of Open Access Journals (Sweden)

    Amanda Andrade Benitez

    2011-10-01

    Full Text Available Cet article propose d’appréhender le processus d’inscription de la question de la contrebande transfrontalière de carburants dans l’agenda d’intégration binational entre la Colombie et le Venezuela. Peu de travaux s’intéressent à ce sujet qui est habituellement abordé dans une perspective de politique intérieure et non pas extérieure. Notre étude s’inscrit dans le cadre théorique de la « mise en agenda » traitée par Cobb et Elders (1983 et des travaux de Jones et Baumgartner (2005 sur l’évolution de l’agenda politique après l’introduction de nouveaux enjeux. Elle vise à comprendre la manière dont la contrebande de carburants trouve une place dans l’agenda d’intégration énergétique bilatéral et devient un enjeu de coopération entre les deux pays. Les effets économiques de la contrebande ainsi que ses conséquences sur la sécurité de la frontière ont été des facteurs déterminants dans la signature d’un accord entre les deux pays. Les agences énergétiques de Colombie et du Venezuela ont été les acteurs privilégiés du processus d’inscription du problème dans l’agenda d’intégration entre les deux pays.This article analyzes the gradual inclusion of the illegal oil trade in the binational integration agenda between Venezuela and Colombia. Few scholars have focused on this question, which is generally examined through the prism of domestic –not foreign– policy. This study borrows from Cobb and Elders’ (1983 agenda setting theory and its development by Jones and Baumgartner (2005 on the evolution of political agendas following the incorporation of new issues. The purpose is to understand the ways in which illegal oil trade found its place in the bilateral energy integration agenda and became the subject of cooperation between Venezuela and Colombia. The economic effects of this illegal traffic along with its consequences on border security were crucial factors in the signing of a

  17. Visualisation of Gasoline and Exhaust Gases Distribution in a 4-Valve Si Engine; Effects of Stratification on Combustion and Pollutants Visualisation de la répartition du carburant et des gaz brûlés dans un moteur à 4 soupapes à allumage commandé ; effet de la stratification sur la combustion et les polluants

    Directory of Open Access Journals (Sweden)

    Deschamps B.

    2006-12-01

    Full Text Available sAn indirect method to map the burned gases in SI engine has been developed. It is based on visualisation by Laser Induced Fluorescence of the unburned mixture seeded with biacetyl. Both internally and externally recirculated burned gases are monitored. This diagnostic is complementary to the LIF technique applied to measure the gasoline distribution. These LIF gasoline and burned gases measurements are applied in a 4-valve optical access SI engine for a large range of operating conditions. These include variations of both fuel injection and burned gas recirculation modes causing different types of stratification leading to very distinct heat release and exhaust emissions characteristics. Tumble level and spark location are also modified. The observation of the actual stratification in the engine forms a sound basis explanation of the engine performance. Parameters allowing an optimisation of NOx and HC levels can be inferred, and in particular the effectiveness of recirculation and fuel injection strategies. The conclusions are confirmed by measurements in a single engine cylinder conventional head with the same geometry. Une méthode indirecte pour cartographier les gaz brûlés dans un moteur à allumage commandé a été développée. Elle est fondée sur une visualisation à partir de la fluorescence induite par laser (LIF du mélange air-carburant non brûlé et ensemencé avec du biacétyl. Les gaz brûlés provenant à la fois des recirculations internes et externes sont observés. Ce type de diagnostic est complémentaire des techniques de LIF utilisées pour observer la distribution du carburant. Ces mesures de concentration sont réalisées dans un moteur à 4 soupapes avec accès optiques, pour une gamme étendue de conditions opératoires. Celles-ci comprennent des variations des modes d'injection du carburant et des modes de recirculation des gaz brûlés, provoquant ainsi différents types de stratifications qui correspondent

  18. Carburation automobile. Contribution à l' étude d'un dispositif d'injection de GPL en phase gazeuse Automotive Fuel: Research on a New Gas-Phase Lpg Injection System

    Directory of Open Access Journals (Sweden)

    Dubois J. P.

    2006-11-01

    Full Text Available Les systèmes de carburation traditionnels aux GPL (induction donnent lieu à un certain nombre d'insatisfactions dues, en particulier, aux difficultés de réglages et à une adéquation imparfaite entre matériels et véhicules. Le système d'injection gazeuse mis au point comporte : - un débitmètre à volet mesurant le débit d'air admis au moteur; - un doseur, lié mécaniquement au volet, et fournissant le mélange air-gaz prédéterminé. Un dispositif d'ouverture forcée du volet permet, lorsqu'on fonctionne à l'essence, de ne pas perturber les performances du carburateur; - un vaporiseur détendeur à deux étages dont les fonctions essentielles sont : - la prédétente à 1,5 bar; - la détente finale à 250 mbar; - l'enrichissement à haut régime; - la sécurité intégrée en cas d'arrêt moteur; - un module de démarrage à froid évitant l'envahissement liquide du vaporiseur jusqu'à 10°C Les avantages de ce dispositif sont : - l'universalité : le même modèle est utilisé sur tous véhicules de 60 à 130 ch; - l'absence de réglage : seul le ralenti est à ajuster; - la maîtrise du rapport air/gaz à la valeur choisie; - le bon compromis performances/consommations; - la prise en compte des paramètres réels de fonctionnement. Conventional LPG induction systems used for transportation purposes do not usually work satisfactory, in particular due to adjustment difficulties and to unsuitable equipment/vehicle matching. The LPG injection system that has been developed comprises:(aa flap flowmeter measuring the air flow into the- engine;(b a proportioning device mechanically connected to the flap and supplying the predetermined air/gas mixture (a device forcing the flap open keeps carburettor performances the same when running on gasoline;(c a two-stage pressure regulator having the following main functions:- initial expansion down to 1. 5 bar;- final expansion down to 250 mbar;- high-speed enrichment;- built-in safety in case

  19. 关节镜下射频松解术治疗成人先天性肌性斜颈%Treatment of adult congenital muscular torticollis with radiofrequency carburation under arthroscope

    Institute of Scientific and Technical Information of China (English)

    刘玉杰; 王俊良; 王志刚; 魏民; 李众利; 朱娟丽; 蔡胥

    2011-01-01

    目的 探讨局麻关节镜下胸锁乳突肌松解治疗先天性肌性斜颈的疗效.方法 局麻关节镜下射频胸锁乳突肌松解术治疗先天性肌性斜颈26例.右侧14例,左侧12例.男11例,女15例,年龄平均22岁.术前标记胸锁乳突肌、锁骨和手术切口.局部浸润麻醉后,在胸锁关节以远10cm,分别作2个5 mm的皮肤切口,沿锁骨中1/3的表面钝性分离出3 cm×5 cm的工作腔隙.置入关节镜和双极射频,紧贴锁骨表面气化切割胸锁乳突肌的胸骨头和锁骨头附着部分.结果 术后随访平均25个月(15~71个月)根据术后颈部活动度、颜面部畸形改善情况、头颈倾斜度和主观感觉满意度评分,优19例,良7例.患者颜面畸形均明显矫正,无瘢痕、复发、复视、血肿及血管神经损伤,疗效满意.结论 局麻关节镜下胸锁乳突肌松解术治疗成人肌性斜颈方法可行,创伤小、操作简便、疗效好、有利于美容.%Objective To evaluate the efficacy of sternoclidomastoideus radiofrequency carburation with local anesthesia under arthroscope for the treatment of congenital muscular torticollis in adults. Methods Twenty-six cases of congenital muscular torticollis were treated by radiofrequency carburetion with local anesthesia under arthroscope. The right side was in 14 patients and left in 12. There were 11 males and 15 females with an average age of 22 years old. Sternoclidomastoideus and clavicula were pre-operatively marked. Through an artificial lacouna, arthroscope and radiofrequency probe were inserted. Results The mean follow-up period was 25 months (range: 15-71 ). According to the motion deficits, craniofacial asymmetry, head tilt and subjective assessment,there were 19 excellent and 7 fair outcomes. Most patients showed a marked improvement in neck motion and head tilt with satisfactory functional and cosmetic outcomes. There was no nerve or vascular injury, no recurrence, infection and scar. The overall efficacy was

  20. Use of Ethanol/Diesel Blend and Advanced Calibration Methods to Satisfy Euro 5 Emission Standards without DPF Utilisation d’un carburant Diesel éthanolé à l’aide de méthodes de calibration avancées afin de satisfaire les normes Euro 5 sans filtre à particules

    Directory of Open Access Journals (Sweden)

    Magand S.

    2011-11-01

    innovative calibration methods, based on the simultaneous optimisation of engine basic settings and cold correction maps, are introduced in order to better suit to the new formulation impact on combustion and catalyst light-off and to drop off engine-out unburned hydrocarbons and carbon monoxide emissions. This stage allows pushing forward the work on test bed facilities in order to reduce the amount of vehicle tests. Tests on a chassis dynamometer are only used to validate the engine test bed results and to perform final tuning of cold correction maps. This alternative blend shows potential to achieve Euro 5 standard with Euro 4 Diesel vehicle configuration, without any hardware modification and without a Diesel particulate filter in the exhaust line. Such an innovative fuel formulation seems to be an interesting answer to the trade-off in the forthcoming years between cost and emissions reduction to achieve sustainable mobility. The presented calibration methods and tools allow to fully take advantage of this alternative fuel in a reduced time scale. L’utilisation des biocarburants s’est développée durant ces dernières années de façon importante afin de diversifier les sources d’énergies et de limiter la hausse des émissions de gaz à effet de serre du secteur des transports. L’un des carburants renouvelables les plus adaptés à une production de masse est l’éthanol. Celui-ci est aujourd’hui principalement utilisé dans les moteurs à allumage commandé, alors que la part des véhicules Diesel sur le marché européen est de l’ordre de 60 %. Ce constat nous a incité à proposer une formulation innovante utilisant de l’éthanol pour les applications Diesel. Les principaux verrous technologiques pour cette utilisation sont la miscibilité, la température d’éclair, la lubrification ou encore l’indice de cétane. Des travaux ont été réalisés pour optimiser la formulation contenant de l’éthanol, des biodiesels de première et seconde g

  1. Utilisation de produits organiques oxygénés comme carburants et combustibles dans les moteurs. Deuxième partie : Les différentes filières d'obtention des carburols. Analyse technico-économique Using Oxygenated Organic Products As Fuels in Engines. Part Two: Different Systems for Producing Alcohol Fuels. Technico-Economic Analysis

    Directory of Open Access Journals (Sweden)

    Chauvel A.

    2006-11-01

    Full Text Available Parmi les produits à même d'être substitués aux hydrocarbures pour la constitution des carburants, les composés organiques oxygénés occupent une place prépondérante à cause de leurs caractéristiques favorables à la combustion dans les moteurs, qu'ils soient employés purs ou mélangés (seuls ou à plusieurs aux hydrocarbures, constituants des carburants classiques. Dans cet article, ces composés oxygénés sont désignés sous le nom de carburols. Alors que l'objet de la première partie de l'étude a été d'examiner les conséquences techniques de l'emploi de ces produits sur les circuits de distribution et le fonctionnement des véhicules, il s'agit dans la présente partie d'analyser les caractéristiques technico-économiques de leur fabrication. En particulier, on y aborde successivement les points suivants : - disponibilités en matières premières : ressources fossiles et végétales ; - analyse technique des divers modes d'obtention - analyse économique ; - programmes nationaux. Among products that can be substituted for hydrocarbons for producing fuels, oxygenated organic compounds occupy a preponderant position because of their favorable characteristics for combustion in engines whether they are used in a pure form or in mixtures (alone or severally with hydrocarbons which are used to make up conventional fuels. In this article these oxygenated compounds are given the name carburols (alcohol fuels. Whereas the aim of Part 1 was to examine the technical consequences of using such products in distribution circuits and for vehicle operating, Part 2 is an analysis of the technico-economic aspects of manufacturing them. In particular, the following points are taken up successively: (a availabilities of raw materials. fossil and vegetebal resources; (b technical analysis of various production methods; (c economic analysis; (d national programs. Depending on the amounts involved, a distinction is made among alternative

  2. Etude d'un procédé d'hydroliquéfaction du charbon pour la production simultanée de gaz et de carburant . . . . . Studies of a Coal Hydrogenation Process to Produce CO-Currently Gas and Gasoline

    Directory of Open Access Journals (Sweden)

    Franckowiak S.

    2006-11-01

    Full Text Available Un des principaux moyens de réintroduire le charbon dans le marché énergétique français est de le transformer en produits utiles comme le gaz de réseau ou les carburants. Les procédés d'oxyvapogazéification permettent d'obtenir un gaz de synthèse qui peut être ensuite converti en gaz riche ou en produits liquides. L'hydrogénation en phase liquide (ou hydroliquéfaction se présente pour le long terme comme une seconde voie qui offre des avantages spécifiques - taux de conversion du charbon et rendement élevés, - production directe de gaz de substitution (GNS et de carburant, - possibilité d'utilisation d'hydrogène provenant de l'électricité nucléaire. Un programme d'étude a été lancé avec la participation du Gaz de France (GDF, du Centre d'études et de recherches des Charbonnages de France (Cerchar, de l'institut Français du Pétrole (lFP et du Centre National de la Recherche Scientifique (CNRS dans le cadre du Groupe d'Étude de la Conversion du Charbon par Hydrogénation (GECH. Un banc d'essai d'hydroliquéfaction situé au Cerchar, d'un débit de 10 kg/h de mélange charbon-solvant, permet d'obtenir des hydrogénats dans des conditions variées et en présence de divers catalyseurs. L'étude de la valorisation de ces hydrogénats est effectuée dans les laboratoires de l'lFP. Les essais et les études effectués permettent d'envisager la production à volonté du GNS, de carburants ou des deux ensemble. Un modèle d'optimisation a été réalisé au GDF pour étudier et comparer les différentes filières en prenant en compte l'utilisation d'hydrogène d'électrolyse ou d'hydrogène produit sur place à partir du résidu de liquéfaction. One of the main ways to bring coal in the future french energy market is to transform it into valuable products. The oxygen steam gasification processes give a synthesis gas which can be converted into SNG or gasoline in a catalytic stage. The liquid phase hydrogenation process is a

  3. 稀土与碳氮原子共渗及其微合金化创新理论%Diffusion and micro-alloying mechanism of rare earth(RE) and carbon/nitrogen atoms permeated into surface layer of steel during RE-carburizing,-nitriding and-nitrocarburizing

    Institute of Scientific and Technical Information of China (English)

    刘志儒; 闫牧夫; 罗群; 郑特强; 陈扬

    2011-01-01

    According to the authors' achievements in RE thermochemical treatment field,the defect theory of solid physics,the diffusion theory,the precipitation theory of secondary phase and the grain refining and ultra-refining theory were combined together based on the classical thermochemical treatment theory.A novel RE thermochemical treatment theory including a new diffusion model has firstly put forward resulting from an establishment of Cottrell atmosphere composed mainly of RE atoms and interstitial atoms such as carbon and nitrogen.A new technical system about new RE-carburizing,-nitriding and-nitrocarburizing of steels was constructed.The application of the new system not only obviously increases the diffusion rate,but also significantly improves the microstructure and service performances.Thus the service life of the parts such as gears treated by the new technologies mentioned above can be prolonged remarkably.%根据作者的研究成果,在经典化学热处理理论基础上把固体物理学新成就中的缺陷理论与扩散理论及析出相固溶析出理论和晶粒细化超细化理论相融合,首次提出了以稀土、间隙碳、氮原子Cottrell气团为核心的稀土化学热处理创新理论,在该领域开创出一种全新的扩散模式。创建了钢中新的稀土渗碳、稀土渗氮及稀土氮碳共渗工艺体系。新体系不仅显著提高了扩散速度,同时又能显著改善微观组织和大幅度提高使用性能,使齿轮类零件的使用寿命显著提高。

  4. Oxidation, carburization and/or sulfidation resistant iron aluminide alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier S.; Hajaligol, Mohammad R.; Lilly, Jr., A. Clifton

    2003-08-19

    The invention relates generally to aluminum containing iron-base alloys useful as electrical resistance heating elements. The aluminum containing iron-base alloys have improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The alloy has an entirely ferritic microstructure which is free of austenite and includes, in weight %, over 4% Al, .ltoreq.1% Cr and either .gtoreq.0.05% Zr or Zro.sub.2 stringers extending perpendicular to an exposed surface of the heating element or .gtoreq.0.1% oxide dispersoid particles. The alloy can contain 14-32% Al, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B. .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, .ltoreq.1% oxygen, .ltoreq.3% Cu, balance Fe.

  5. Potential New Sensor for Use With Conventional Gas Carburizing

    Science.gov (United States)

    deGroot, W. A.

    1997-01-01

    Diagnostics developed for in-situ monitoring of rocket combustion environments have been adapted for use in heat treating furnaces. Simultaneous, in-situ monitoring of the carbon monoxide, carbon dioxide, methane, water, nitrogen and hydrogen concentrations in the endothermic gas of a heat treating furnace has been demonstrated under a Space Act Agreement between NASA Lewis, the Heat Treating Network, and Akron Steel Treating Company. Equipment installed at the Akron Steel Treating Company showed the feasibility of the method. Clear and well-defined spectra of carbon monoxide, nitrogen and hydrogen were obtained by means of an optical probe mounted on the endothermic gas line of a gas generator inside the plant, with the data reduction hardware located in the basement laboratory. Signals to and from the probe were transmitted via optical fibers.

  6. Evaluation of CBS 600 carburized steel as a gear material

    Science.gov (United States)

    Townsend, D. P.; Parker, R. J.; Zaretsky, E. V.

    1979-01-01

    Gear endurance tests were conducted with one lot of consumable-electrode vacuum-melted (CVM) AISI 9310 gears and one lot of air-melt CBS 600 gears. The gears were 8 pitch with a pitch diameter of 8.89 centimeters (3.5 in.). Bench-type rolling-element fatigue tests were also conducted with one lot of CVM AISI 9310, three lots of CVM CBS 600, and one of air-melt CBS 600 material. The rolling-element bars were 0.952 centimeter (0.375 in.) in diameter. The CBS 600 material exhibited pitting fatigue lives in both rolling-element specimens and gears at least equivalent to that of CVM AISI 9310. Tooth fracture failure occurred with the CBS 600 gears after overrunning a fatigue spall, but it did not occur with the CVM AISI 9310 gears. Tooth fracture in the CBS 600 was attributed to excessive carbon content in the case, excessive case depth, and a higher than normal core hardness.

  7. Noble-metal nanostructures on carburized W(110).

    Science.gov (United States)

    Bachmann, Magdalena; Memmel, Norbert; Bertel, Erminald

    2011-07-01

    Noble metal nanostructures of Au, Ag and Cu were prepared on two types of carbon-modified W(110) surfaces-R(15 × 12) and R(15 × 3)-and investigated by means of scanning tunneling microscopy. For all deposited metals qualitatively the same behaviour is observed: On the R(15 × 12)-template always isotropic clusters are formed. In contrast, on the R(15 × 3)-substrate the anisotropy of the nanostructures can be tuned from clusters at low temperatures via thin nanowires to thicker nanobars at high deposition temperatures. At intermediate temperatures on the R(15 × 3) the anisotropic Au nanowires arrange themselves into straight lines along domain boundaries induced by deposition of the Au metal. Similarities and differences to Au nanostructures as recently reported by Varykhalov et al. [A. Varykhalov, O. Rader, W. Gudat. Physical Review B 77, 035412 (2008).] are discussed.

  8. Hydraulic Hybrid Propulsion for Heavy Vehicles: Combining the Simulation and Engine-In-the-Loop Techniques to Maximize the Fuel Economy and Emission Benefits Propulsion hybride hydraulique des poids lourds : une approche alliant les techniques de simulation et d’« Engine-In-the-loop » (EIL afin de maximiser les économies de carburant et les avantages en termes d’émissions

    Directory of Open Access Journals (Sweden)

    Filipi Z.

    2009-09-01

    échauffement climatique fournissent une forte motivation pour le développement de moyens de propulsion véhiculaires économes. Pour les camions, cette tâche est particulièrement difficile à accomplir du fait d’importantes contraintes de taille et de poids. L’hybridation est la seule approche qui puisse déboucher sur des progrès importants à court et moyen termes. En particulier, la configuration “hybride série” découple le moteur thermique des roues et permet une flexibilité complète dans le contrôle des points de fonctionnement moteur. De plus, la conversion et le stockage de l’énergie hydraulique fournissent une densité de puissance et un rendement excellents. Le défi technologique tient à la faible densité d’énergie de l’accumulateur hydraulique, et met en avant l’importance particulière du développement du gestionnaire de l’énergie. Il est communément admis qu’il faut maintenir le moteur au point de rendement maximum mais, si l’objectif ultime en terme énergétique consiste à optimiser drastiquement le rendement du moteur, ceci induit des phases transitoires fréquentes causant pour des moteurs diesels des effets opposés tant sur l’émission de particules que sur l’agrément de conduite. Par conséquent, nous proposons une méthodologie pour le superviseur d’énergie d’un système hybride, qui prend en compte 2 objectifs : la réduction de consommation et la réduction des émissions polluantes. Les économies de carburant sont prises en compte par une approche fondée sur la simulation, alors que l’étude de l’impact des phases transitoires du moteur sur les émissions de particules, est fondée sur un dispositif expérimental combinant modèles temps réel et moteur réel – l’EIL (Engine-In-the-Loop. Le dispositif EIL confirme que le contrôle de la répartition énergétique thermique/hydraulique de l’état de charge des batteries (SOC présente des avantages certains sur celui basé sur l’approche de contr

  9. Modelingof Acetylene Pyrolysis under Steel Vacuum Carburizing Conditions in a Tubular Flow Reactor

    Directory of Open Access Journals (Sweden)

    Rainer Reimert

    2007-03-01

    Full Text Available In the present work, the pyrolysis of acetylene was studied under steel vacuumcarburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from650 °C to 1050 °C. The partial pressure of acetylene in the feed mixture was 10 and 20mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressureof the mixture was 1.6 bar. A kinetic mechanism which consists of seven species andnine reactions has been used in the commercial computational fluid dynamics (CFDsoftware Fluent. The species transport and reaction model of Fluent was used in thesimulations. A comparison of simulated and experimental results is presented in thispaper.

  10. Surface Fatigue Lives of Case-Carburized Gears With an Improved Surface Finish

    Science.gov (United States)

    Krantz, T. L.; Alanou, M. P.; Evans, H. P.; Snidle, R. W.; Krantz, T. L. (Technical Monitor)

    2000-01-01

    Previous research provides qualitative evidence that an improved surface finish can increase the surface fatigue lives of gears. To quantify the influence of surface roughness on life, a set of AISI 93 10 steel gears was provided with a nearmirror finish by superfinishing. The effects of the superfinishing on the quality of the gear tooth surfaces were determined using data from metrology, profilometry, and interferometric microscope inspections. The superfinishing reduced the roughness average by about a factor of 5. The superfinished gears were subjected to surface fatigue testing at 1.71 -GPa (248-ksi) Hertz contact stress, and the data were compared with the NASA Glenn gear fatigue data base. The lives of gears with superfinished teeth were about four times greater compared with the lives of gears with ground teeth but with otherwise similar quality.

  11. Method of nitriding, carburizing, or oxidizing refractory metal articles using microwaves

    Science.gov (United States)

    Holcombe, Cressie E.; Dykes, Norman L.; Tiegs, Terry N.

    1992-01-01

    A method of nitriding an article of refractory-nitride-forming metal or metalloids. A consolidated metal or metalloid article is placed inside a microwave oven and nitrogen containing gas is introduced into the microwave oven. The metal or metalloid article is heated to a temperature sufficient to react the metal or metalloid with the nitrogen by applying a microwave energy within the microwave oven. The metal or metalloid article is maintained at that temperature for a period of time sufficient to convert the article of metal or metalloid to an article of refractory nitride. in addition, a method of applying a coating, such as a coating of an oxide, a carbide, or a carbo-nitride, to an article of metal or metalloid by microwave heating.

  12. Smelting in cupola furnace for re carburization of direct reduction iron (DRI)

    Energy Technology Data Exchange (ETDEWEB)

    Enriquez, J. L.; Tremps, E.; Ruiz-Bustinza, I.; Moron, C.; GarciaGarcia, A.; Robla, J. I.; Gonzalez-Gasca, C.

    2015-07-01

    Herein the synthesis of iron-carbon saturated alloys (foundries) melting in cupola furnaces from direct reduction iron is described. The fundamentals are reviewed and combinations undertaken are discussed along with their results, including conclusions and recommendations for follow up. (Author)

  13. Conception et réalisation de composants unipolaires en Carbure de Silicium

    OpenAIRE

    BERTHOU, Maxime

    2012-01-01

    In this document, we present ou study about the conception and realization of VMOS and Schottky and JBS Diodes on Silicon Carbide. This work allowed us optimize and fabricate diodes using Tungsten as Schottky barrier on both Schottky and JBS diodes of different blocking capability between 1.2kV and 9kV. Moreover, our study of the VMOS, by considering the overall fabrication process, has permitted to identify the totality of the problems we are facing. Thusly we could ameliorate the devices an...

  14. Synthèse de Fischer Tropsch sur support conducteur à base de carbure de silicium

    OpenAIRE

    Tymowski, Benoît de

    2012-01-01

    The Fischer-Tropsch synthesis (FTS) allows the transformation of a mixture of synthesis gas, i.e. H2 and CO, into valuable liquid hydrocarbons. The catalysts generally used in FTS are based on iron or cobalt supported on alumina or silica. ln the present work, silicon carbide (SiC) has been proposed as a replacement media to traditional supports. The results obtained indicate that the mesoporous SiC containing cobalt catalyst exhibits a good FTS activity and an extremely high selectivity towa...

  15. Elaboration de nanostructures à une dimension à base de carbure de silicium.

    OpenAIRE

    Ollivier, Maelig

    2013-01-01

    Due to their superior physical and chemical properties —such as high breakdown field, high thermalconductivity and biocompatibility— compared to other semiconductors, silicon carbide is forseento be a promising materials for power electronics, bio-nano-sensors and nano-electronics in harsh environments.However, among the numerous top-down or bottom-up methods used to synthesise siliconcarbide 1D nano-objects, none has been able yet to produce SiC with a high cristalline quality.The aim of thi...

  16. IMPACT OF CARBURIZING AND BOROSILICONIZING ON VIBROACCELERATION OF BEVEL GEAR FRONT DRIVE AXLE SKIDDERS DURING OPERATION

    Directory of Open Access Journals (Sweden)

    M. N. Pischov

    2015-01-01

    Full Text Available It is now established that the main causes of failure of the transmission parts of the forest machines is wear of their working surfaces. The destruction of the contact surfaces of bevel gears front axle of skidder TTP-401 during its operation is usually connected, with the formation of plastic deformation on the teeth. According to modern concepts of the theory of the destruction of the details revealed that after the formation of plastic deformations leads to microcracks, the development of micro tracks depends on the magnitude and sign of residual stresses. This article presents dependance graphs of vibration acceleration bevel gears front axle skidder subiect to the method of hardening.

  17. Fuels and alternative propulsion in Germany; Les carburants et propulsion alternatifs en Allemagne

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-04-15

    The transportation sector is one of the first responsible of the air pollution in Germany. The kyoto protocol and the european directive led the german Government to set about some measures. To encourage the petroleum industry to develop classical fuels/biofuels mixing, the government exempted from taxes until 2020 the biofuels part. The Government decided also financial incentives for diesel vehicles equipped with particles filters. Among the different fuels, the document presents the advantages and disadvantages of the hydrogen fuels and the hybrid motors. (A.L.B.)

  18. Alcool : carburant du corps-machine (à écrire

    Directory of Open Access Journals (Sweden)

    Sophie Dubois

    2009-09-01

    Full Text Available De prime abord, il peut paraître banal d’envisager l’œuvre de Victor-Lévy Beaulieu sous l’angle de l’aliénation. En effet, maints critiques – dont Jacques Pelletier – ont déjà démontré que les personnages beaulieusiens sont « des êtres excessifs, pour ainsi dire des fous » ou des « figures pitoyables exprimant et symbolisant la condition d’aliénation, de dépossession, de déculturation sociale et historique du Canada français et l’abandon, la mollesse, la passivité avec lesquelles on peut la s...

  19. Heat Treatment Ballistic and Metallurgical Test of Face Hardened Armor Carburized by the Lithium Catalyst Process

    Science.gov (United States)

    1952-03-24

    sdhe. *t$- .sßgM’ts w&s Wart-eateä^ . Siiniiör to thai tihSsh. is. iaftf&BftUjr uw .for 1/2" f«ee ha* gene & arciö* alai-ä-aä « Basis l*or epfepair...lO-SOH IMM y’«^ 1 I LsGHT «RMüR FiRiNG RECORD PRHC- KPC ---5» \\ ; i SHEET NO. Ä X f. X X TEMPERATURE Tlk*E ANNEAL YP NORM TS KARDEN...PRKC- KPC —5?« *v J o SHEET HO- End. ( ?LATE ÄO& 9 J % • / S>z^¥" RD. 8ÜLLET - - CHARGE STRIKING VELOCITY • OBL. YAW PENET. BULLET

  20. The technologies for heavy vehicles motors and their fuels; Les technologies des moteurs de vehicules lourds et leurs carburants

    Energy Technology Data Exchange (ETDEWEB)

    Plassat, G.

    2005-07-01

    The heavy vehicles are those the total weight (charged) is more than 3,5 tons. This document provides a comparative and parametric analysis of the main technologies developed for the future buses. A detailed presentation is done for each technique, as the operating principles and the advantages and disadvantages facing the today solution. More particularly the author presents the evolution of the diesel-fuel motor, the motor optimization for specific fuel as the natural gas and the liquefied petroleum gas, the hybrid thermal-electric motor, the hydrogen fuel cells, the biofuels and the de-pollution systems to eliminate the NO{sub X} and the particles. (A.L.B.)

  1. Development of a carburizing and quenching simulation tool: A material model for low carbon steels undergoing phase transformations

    Energy Technology Data Exchange (ETDEWEB)

    Bammann, D.; Prantil, V.; Kumar, A. [Sandia National Labs., Livermore, CA (United States)] [and others

    1996-06-24

    An internal state variable formulation for phase transforming alloy steels is presented. We have illustrated how local transformation plasticity can be accommodated by an appropriate choice for the corresponding internal stress field acting between the phases. The state variable framework compares well with a numerical micromechanical calculation providing a discrete dependence of microscopic plasticity on volume fraction and the stress dependence attributable to a softer parent phase. The multiphase model is used to simulate the stress state of a quenched bar and show qualitative trends in the response when the transformation phenomenon is incorporated on the length scale of a global boundary value problem.

  2. Fuels production by the thermochemical transformation of the biomass; La production de carburants par transformation thermochimique de la biomasse

    Energy Technology Data Exchange (ETDEWEB)

    Claudet, G. [CEA, 75 - Paris (France)

    2005-07-01

    The biomass is a local and renewable energy source, presenting many advantages. This paper proposes to examine the biomass potential in France, the energy valorization channels (thermochemical chains of thermolysis and gasification) with a special interest for the hydrogen production and the research programs oriented towards the agriculture and the forest. (A.L.B.)

  3. Lattice dynamics of {alpha} boron and of boron carbide; Proprietes vibrationnelles du bore {alpha} et du carbure de bore

    Energy Technology Data Exchange (ETDEWEB)

    Vast, N

    1999-07-01

    The atomic structure and the lattice dynamics of {alpha} boron and of B{sub 4}C boron carbide have been studied by Density Functional Theory (D.F.T.) and Density Functional Perturbation Theory (D.F.P.T.). The bulk moduli of the unit-cell and of the icosahedron have been investigated, and the equation of state at zero temperature has been determined. In {alpha} boron, Raman diffusion and infrared absorption have been studied under pressure, and the theoretical and experimental Grueneisen coefficients have been compared. In boron carbide, inspection of the theoretical and experimental vibrational spectra has led to the determination of the atomic structure of B{sub 4}C. Finally, the effects of isotopic disorder have been modeled by an exact method beyond the mean-field approximation, and the effects onto the Raman lines has been investigated. The method has been applied to isotopic alloys of diamond and germanium. (author)

  4. Biodegradability of fuel-ethers in environment; Biodegradabilite des ethers-carburants dans l'environnement

    Energy Technology Data Exchange (ETDEWEB)

    Fayolle-Guichard, F.

    2005-04-01

    Fuel ethers (methyl tert-butyl ether or MTBE, ethyl tert-butyl ether or ETBE and tert-amyl methyl ether or TAME have been used as gasoline additives since about twenty years in order to meet the requirements for the octane index and to limit the polluting emission in exhaust pipe gas (unburnt hydrocarbons and carbon monoxide). The high water solubility and the poor biodegradability of these compounds make them pollutants frequently encountered in aquifers. The present manuscript summarizes the knowledge concerning the biodegradability of fuel ethers obtained both at IFP and during collaborations with the Pasteur Institute (Paris), the Biotechnology Research Institute (Montreal, Canada) and the Center for Environmental Biotechnology (University of Tennessee, USA). Rhodococcus ruber IFP 2001 and Mycobacterium austroafricanum IFP 2012, two microorganisms isolated at IFP for their ability to grow, respectively, on ETBE and MTBE, were studied in order to determine the intermediates produced during MTBE and ETBE biodegradation and the enzymes required for each biodegradation step, thus allowing us to propose MTBE and ETBE catabolic pathways. A proteomic approach, from the protein induced during the degradation of ETBE or MTBE to the genes encoding these different enzymes, was carried out. The isolation of such genes is required:1) to use them for help in determining the bio-remediation capacities in polluted aquifers (DNA micro-arrays), 2) to monitor the microorganisms isolated for their degradative capacities during bio-remediation processes (fluorescent in situ hybridization or FISH) and 3) to create new tools for the detection and the quantification of ETBE or MTBE in contaminated aquifers (bio-sensor). The manuscript also describes the different ways for the adaptation of microorganisms to the presence of a xenobiotic compound. (author)

  5. Etude d'interrupteurs en carbure de silicium et potentiel d'utilisation dans des applications aéronautiques

    OpenAIRE

    Othman, Dhouha

    2015-01-01

    The potential of wide band gap transistors based on silicon carbide are remarkable and open new prospects for improvement (high efficiency, high breakdown voltage, high switching frequency and high operating temperature ...). This leads to volume and weight reduction for future converters. In order to improve new generation of power converters for future needs, Thales, in cooperation with SATIE and LTN IFSTTAR laboratories, performs investigations on the performances, advantages and disadvant...

  6. Elaboration de céramiques poreuses ordonnées à base de carbure de silicium

    OpenAIRE

    Majoulet, Olivier

    2012-01-01

    SiC based non-oxide type ceramics have been largely studied due to high thermostructural properties.In particular, Silicoboron carbonitrides (SiBCN) display high mechanic reliability and stay stableuntil temperature such as 2200 °C due to a low atomic mobility in their structure. The developpementof the Polymer Derived Ceramics (PDCs) route played a major role in the production of technicalceramics with controlled properties. Through the thermolysis of preceramic polymers, a large rangeof cer...

  7. Kinetics of niobium carbide precipitation in ferrite; Cinetiques de precipitation du carbure de niobium dans la ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Gendt, D

    2001-07-01

    The aim of this study is to develop a NbC precipitation modelling in ferrite. This theoretical study is motivated by the fact it considers a ternary system and focus on the concurrence of two different diffusion mechanisms. An experimental study with TEP, SANS and Vickers micro-hardening measurements allows a description of the NbC precipitation kinetics. The mean radius of the precipitates is characterized by TEM observations. To focus on the nucleation stage, we use the Tomographic Atom Probe that analyses, at an atomistic scale, the position of the solute atoms in the matrix. A first model based on the classical nucleation theory and the diffusion-limited growth describes the precipitation of spherical precipitates. To solve the set of equations, we use a numerical algorithm that furnishes an evaluation of the precipitated fraction, the mean radius and the whole size distribution of the particles. The parameters that are the interface energy, the solubility product and the diffusion coefficients are fitted with the data available in the literature and our experimental results. It allows a satisfactory agreement as regards to the simplicity of the model. Monte Carlo simulations are used to describe the evolution of a ternary alloy Fe-Nb-C on a cubic centred rigid lattice with vacancy and interstitial mechanisms. This is realized with an atomistic description of the atoms jumps and their related frequencies. The model parameters are fitted with phase diagrams and diffusion coefficients. For the sake of simplicity, we consider that the precipitation of NbC is totally coherent and we neglect any elastic strain effect. We can observe different kinetic paths: for low supersaturations, we find an expected precipitation of NbC but for higher supersaturations, the very fast diffusivity of carbon atoms conducts to the nucleation of iron carbide particles. We establish that the occurrence of this second phenomenon depends on the vacancy arrival kinetics and can be related to the microstructure of the steel. (author)

  8. The sustainable development of transports: the motors and the fuels; Le developpement durable des transports: quels moteurs, quels carburants?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2005-07-01

    This panorama 2005 between politicians, industrialists and scientists discussed the following topics: exploration-production activities and markets, refining and petrochemistry, the future world gas market, the petroleum supply and demand, the new petroleum and gas reserves, the today and tomorrow alternative fuels, the biofuels in the world, the hybrid vehicles future, the energy consumption in the transport sector, the road fuels in europe and the increase of diesel fuel, the de-pollution techniques of industrial vehicles. The slides of the interventions are provided. The sheets ''le point sur'' of the year 2005 are also provided. (A.L.B.)

  9. Preparation of porous silicon carbide from molecular precursors; Preparation de carbure de silicium poreux a partir de precurseurs moleculaires

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, J

    2008-02-15

    The preparation of Porous Silicon Carbide (SiC) from molecular precursors is described in this work. Firstly, poly-silane and poly-carbo-silane were synthesised from targeted molecular precursors TSCH and TCDSCB. The pyrolysis of these polymers under inert conditions gave the SiC. Secondly, the preparation of functional poly-silane was explored. It was shown that Cp{sub 2}Ti(OPh){sub 2} was a suitable catalyst for the preparation of such functional poly-silane in a one-pot process. Finally, macroporous SiC were prepared from hard templating method by using a commercial silica. (author)

  10. Hydrogen fuel: Japan tries to pull away; Carburant hydrogene: le Japon tente de prendre de l'avance

    Energy Technology Data Exchange (ETDEWEB)

    Henry, P.

    2003-04-01

    The energy production of Japan is highly dependent from its oil and gas imports. Thus, Japan tries to diversify its energy sources in order to find alternate solutions to this dependence. Hydrogen should be one of these solutions providing that some economically and environmentally viable hydrogen production techniques are implemented with reliable and competitive distribution networks. The 'world energy network' (WE-NET) program, started thanks to Japan's impetus, aims at establishing a large scale international network for the development of hydrogen as energy source. (J.S.)

  11. Production de bio-carburants de 3ème génération à partir de microalgues

    OpenAIRE

    Ramirez, Lis,

    2013-01-01

    Given the depletion of fossil fuels and to meet a growing demand for transportation energy, scientists are now turning towards an almost inexhaustible and renewable resource: biomass. As biomass, microalgae represent a potential source of biofuel because they may contain high levels of lipids and hydrocarbons. Their extremely fast growth, the use of CO2 and solar energy for their growth and the absence of competition with traditional agriculture makes microalgae very appealing. Two thermochem...

  12. La production de carburants à partir de biomasse lignocellulosique par voie biologique : état de l’art et perspectives

    Directory of Open Access Journals (Sweden)

    O’Donohue Michael J.

    2008-05-01

    Full Text Available In the current international context, the development of industrial technology that will allow the production of agro-fuels from lignocellulosic biomass is becoming ever more important for society. However, despite over thirty years of research, several hurdles still have to be surmounted before the first industrial facilities begin to produce ethanol. Nevertheless, thanks to its ability to generate innovative, clean and sustainable solutions for industry, biotechnology is now well-poised to provide new solutions aimed at the full exploitation of biomass resources, not only to make fuels, but also a wide range of fine chemicals and products that are required by modern society.

  13. Corrosion of alloy 800H and the effect of surface-applied CeO2 in a sulphidizing/oxidizing/carburizing environment at 700°C

    NARCIS (Netherlands)

    Stroosnijder, M.F.; Guttmann, V.; Fransen, T.; Wit, de J.H.W.

    1990-01-01

    The corrosion behavior of a wrought austenitic Fe-20Cr-32Ni steel, Alloy 800H, was studied in a simulated coal-gasification atmosphere at 700°C for exposure times up to 2500 hr. The influence of preoxidation and CeO2-surface application followed by preoxidation on the corrosion resistance of this ma

  14. Surface fatigue life of carburized and hardened M50NiL and AISI 9310 spur gears and rolling-contact test bars

    Science.gov (United States)

    Townsend, Dennis P.; Bamberger, Eric N.

    1989-01-01

    Spur gear endurance tests and rolling-element surface tests were conducted to investigate vacuum-induction-melted, vacuum-arc-melted (VIM-VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling-contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm (3.5 in.). Gear test conditions were an inlet oil temperature of 320 K (116 F), and outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench rolling-element fatigue tests were conducted at ambient temperatures with a bar speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPA (700 ksi). The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling-contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR M50NiL material was shown to have good resistance to fracture through a fatigue spall and to have fatigue life far superior to that of both VIM-VAR and VAR AISI 9310 gears and rolling-contact bars.

  15. 钛合金电火花表面渗碳研究%Research of Surface Carburizing on Titanium Alloys by Electrospark Deposition

    Institute of Scientific and Technical Information of China (English)

    游涛; 黄大伟; 刘时兵; 刘宏宇; 张春辉; 苏贵桥; 王茂才

    2007-01-01

    用电火花渗碳技术可在钛合金表面形成一层40~50 μm厚的渗碳层,分析显示渗碳层中主要是由石墨电极与基体反应生成的TiC相组成.渗碳层与基体之间没有明显的界面,组织和成分过渡均匀.TA2合金渗碳层的显微硬度最高可达2000HV0.05,是基体的5~7倍;整个渗层截面的硬度呈梯度分布.

  16. Analysis of Surface Carbon Content in Carburized Automobile Components%汽车零件渗碳表面含碳量分析

    Institute of Scientific and Technical Information of China (English)

    金华; 沈建军; 许文瑞

    2008-01-01

    研究了汽车零件渗碳热处理后渗碳层表面含碳量与碳浓度分布梯度、渗碳层深度、表面正常淬火组织、表面应力状态及渗碳件淬火变形量之间的关系,为了满足NB喷油泵中的重要零件凸轮轴使用10×105 km无故障的目标要求,对原热处理加工工艺进行了设计改进,并作了新旧两种工艺的对比试验.

  17. Catalyseurs à base de cobalt supportés sur carbure de silicium et nano-carbones pour la synthèse de Fischer-Tropsch

    OpenAIRE

    Liu, Yuefeng

    2013-01-01

    The Fischer-Tropsch synthesis (FTS) is a key technology to transform the synthesis gas (2H2 + CO) into liquid hydrocarbons as the basic chemical feedstock. It can be found that the cobalt active sites supported on the materials with high thermal conductivity, opened structure is necessary to accelerate FTS synthesis process in the development of industry catalysts.In this work, a new hierarchical support consisting of α-Al2O3, which is homogeneously covered by a layer of carbon nanotubes, is ...

  18. Study of boron carbide evolution under neutron irradiation; Contribution a l'etude de l'evolution du carbure de bore sous irradiation neutronique

    Energy Technology Data Exchange (ETDEWEB)

    Simeone, D. [CEA/Saclay, Dept. de Mecanique et de Technologie (DMT), 91 - Gif-sur-Yvette (France)]|[Universite Blaise Pascal, Clermont-Ferrand II, (CNRS), 63 - Aubiere (France)

    1999-07-01

    Owing to its high neutron efficiency, boron carbide (B{sub 4}C) is used as a neutron absorber in control rods of nuclear plants. Its behaviour under irradiation has been extensively studied for many years. It now seems clear that brittleness of the material induced by the {sup 10}B(n,{alpha}){sup 7}Li capture reaction is due to penny shaped helium bubbles associated to a high strain field around them. However, no model explains the behaviour of the material under neutron irradiation. In order to build such a model, this work uses different techniques: nuclear microprobe X-ray diffraction profile analysis and Raman and Nuclear Magnetic Resonance Spectroscopy to present an evolution model of B{sub 4}C under neutron irradiation. The use of nuclear reactions produced by a nuclear microprobe such as the {sup 7}Li(p,p'{gamma}){sup 7}Li reaction, allows to measure lithium profile in B{sub 4}C pellets irradiated either in Pressurised Water Reactors or in Fast Breeder Reactors. Examining such profiles enables us to describe the migration of lithium atoms out of B{sub 4}C materials under neutron irradiation. The analysis of X-ray diffraction profiles of irradiated B{sub 4}C samples allows us to quantify the concentrations of helium bubbles as well as the strain fields around such bubbles.Furthermore Raman spectroscopy studies of different B{sub 4}C samples lead us to propose that under neutron irradiation. the CBC linear chain disappears. Such a vanishing of this CBC chain. validated by NMR analysis, may explain the penny shaped of helium bubbles inside irradiated B{sub 4}C. (author)

  19. 20CrNi2Mo渗碳轴承钢的变形抗力%Deformation resistance of carburizing bearing steel 20CrNi2Mo

    Institute of Scientific and Technical Information of China (English)

    李彬周; 张建; 李长生; 李忠之; 乔兵

    2014-01-01

    Using the MMS‐300 thermal mechanical simulator ,the deformation resistance of 20CrNi2Mo steel with strain 0~0.8 and strain rate 0.01s-1 ~10s-1 at 850℃ ~1 150℃ in single pass axial compression process is tested and studied ,and the relation‐ship among deformation temperature ,strain rate ,degree of deformation and deformation resistance has been determined .The re‐sults show that the deformation resistance is affected remarkably by both strain rate and deformation temperature ,the deformation resistance decreases with the increase of temperature ,and it increases with the increase of strain rate .In addition ,the interaction of deformation temperature ,strain rate and degree of deformation affects the deformation resistance together .Through multiple non-linear regression analysis ,the deformation resistance model for the 20CrNi2Mo steel is established ,and this model proved to have good curve fitting characteristics and relatively high precision .%利用M M S‐300热/力模拟实验机,在变形温度850℃~1150℃、应变量0~0.8和应变速率0.01 s-1~10s-1条件下对20CrNi2Mo钢进行高温单道次压缩实验,分析变形温度、变形速率和变形程度对变形抗力的影响。结果表明,变形温度和变形速率对20CrNi2Mo钢变形抗力的影响最为强烈:20CrNi2Mo钢变形抗力随变形温度的升高而减小,随变形速率的提高而增大;且变形温度、变形速率和应变量3个因素之间相互作用,共同影响变形抗力。利用多元非线性回归建立了20CrNi2Mo钢高温变形抗力数学模型,与实测值比较表明,模型拟合程度较好。

  20. Heterogeneous precipitation of niobium carbide in the ferrite by Monte Carlo simulations; Cinetique de precipitation heterogene du carbure de niobium dans la ferrite

    Energy Technology Data Exchange (ETDEWEB)

    Hin, C

    2005-12-15

    The precipitation of niobium carbides in industrial steels is commonly used to control the recrystallization process or the amount of interstitial atoms in solid solution. It is then important to understand the precipitation kinetics and especially the competition between homogeneous and heterogeneous precipitation, since both of them have been observed experimentally, depending on they alloy composition, microstructure and thermal treatments. We propose Monte Carlo simulations of NbC precipitation in {open_square}-iron, based on a simple atomic description of the main parameters which control the kinetic pathway: - Realistic diffusion properties, with a rapid diffusion of C atoms by interstitial jumps and a slower diffusion of Fe and Nb atoms by vacancy jumps; - A model of grain boundaries which reproduces the segregation properties of Nb and C; - A model of dislocation which interacts with solute atoms through local segregation energies and long range elastic field; - A point defect source which drives the vacancy concentration towards its equilibrium value. Depending on the precipitation conditions, Monte Carlo simulations predict different kinetic behaviors, including a transient precipitation of metastable carbides, an early segregation stage of C, wetting phenomena at grain boundaries and on dislocations and a competition between homogeneous and heterogeneous NbC precipitation. Concerning the last point, we highlight that long range elastic field due to dislocation favors clearly the heterogeneous precipitation on dislocations. To understand this effect, we have developed a heterogeneous nucleation model including the calculation of the local concentration of solute atoms around the dislocation, the change of the solubility limit relative to the solubility limit in bulk and the energy of precipitates in an elastic field. We have concluded that elastic field favors the heterogeneous precipitation through the fall in nucleation barrier. (author)

  1. Development of Integrated TiO2 on Carburized Si Nanowires as a Catalyst/Support Structure for Alkaline Fuel Cells

    Science.gov (United States)

    Lemke, Adam J.

    Due to a combination of environmental and economic motivations, there is a strong impetus to transition away from fossil fuels towards renewable sources of energy. Critical to achieving this goal will be technologies that allow for the storage and transmission of energy derived from renewable sources. Hydrogen fuel cells may play a significant role in making this a reality, allowing for the use of hydrogen as a non-carbon based fuel, in particular for vehicle applications. Hydrogen fuel cells directly convert chemical energy into electrical energy, with only water vapor and heat as waste products. There are challenges facing fuel cell technology that inhibit its wider implementation. One of the most significant of these is the cost of the platinum that is typically used in fuel cells to catalyze the oxygen reduction reaction (ORR), which is the bottleneck reaction in hydrogen fuel cells. The rarity and expense of platinum significantly add to the cost of fuel cells, thus reducing their economic viability. Therefore there is much interest in developing catalysts from alternative materials with a lower cost. A second, and related issue facing fuel cells is the degradation over time of the support structure that puts the catalyst into electrical connection with the external load. The carbon structure that currently serves as the standard catalyst support degrades over time under the harsh operating conditions of the cell, leading to catalyst agglomeration and reducing the lifetime of the cell. It is therefore desirable to develop support structures that will be more stable, while still providing electrical conductivity. The following presents original research pertaining to the development of catalyst/support materials making use of non-noble metal oxides synthesized by means of wet chemical methods. Metal oxides such as manganese oxide and titanium oxide are capable of serving as support materials and (in the case of alkaline fuel cells) even as catalysts. Wet chemical techniques were chosen due to their relative economy and simplicity, obviating the need for expensive specialized equipment, and the ease with which such processes may be scaled up. The aim of this research was the development of a more stable catalyst/support structure, replacing the graphitic carbon that is traditionally used, focusing on both alkaline and acidic systems.

  2. Fuel consumption of private cars in France 1988-2006; Consommations de carburants des voitures particulieres en France 1988-2006

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2007-12-15

    The results of this study come from the exploitation of the 'TNSworldpanel Petrol' inquiry launched in April 1987. This panel follows the consumption of 3300 cars belonging to individuals living in France (company vehicles are excluded). This is the only operation of this scale ever carried out in France. The main results indicate: the continuation of the average consumption decay of individual cars (all kind of fuel considered); a new and significant progress of diesel-fueled vehicles: 57% of the cars purchased by households (50% in 2003, 33% in 1995); a new decay of the total distance covered by households: -1.1% in parallel to the rise of fuel prices. (J.S.)

  3. Fuel consumption and CO{sub 2} emissions (Car Labelling); Consommations de carburant et emissions de CO{sub 2} (Car Labelling)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-03-01

    CO{sub 2} is the most important greenhouse gas produced by internal combustion engines. In the framework of the Kyoto protocol, actions have been implemented in the transportation sector for the abatement of vehicles fuel consumption and pollutant emissions. This study presents the 'honors list' established by the French agency of environment and energy mastery (Ademe) of the fuel consumption and CO{sub 2} emissions of gasoline, diesel, LPG, NGV, and hybrid electric-powered vehicles. Results are presented in tables per company and model. These data are compiled and summarized in a last part which presents the key data about the evolution of the French automotive market, the emissions and consumptions of vehicles and the technological evolution of the vehicles and its influence on the fuel consumption. (J.S.)

  4. Motor fuel demand analysis - applied modelling in the European union; Modelisation de la demande de carburant appliquee a l`europe

    Energy Technology Data Exchange (ETDEWEB)

    Chorazewiez, S

    1998-01-19

    Motor fuel demand in Europe amounts to almost half of petroleum products consumption and to thirty percent of total final energy consumption. This study considers, Firstly, the energy policies of different European countries and the ways in which the consumption of motor gasoline and automotive gas oil has developed. Secondly it provides an abstract of demand models in the energy sector, illustrating their specific characteristics. Then it proposes an economic model of automotive fuel consumption, showing motor gasoline and automotive gas oil separately over a period of thirty years (1960-1993) for five main countries in the European Union. Finally, forecasts of consumption of gasoline and diesel up to the year 2020 are given for different scenarios. (author) 330 refs.

  5. Sample Preservation - The Key to a Successful Failure Analysis

    Science.gov (United States)

    2008-09-01

    carburized tool steel. The outer surface rehardened, transforming into unstable, untempered martensite. The case below this layer was affected...Rehardening and retempering burn in a carburized tool steel subjected to abusive grinding. Litigation: High visibility failures leading to

  6. Sulfur Tolerance of Carbide Catalysts Under Hydrocarbon Reforming Conditions

    Science.gov (United States)

    2007-11-02

    with a low surface area bulk catalyst produce similar activities. In addition it was also found that incomplete carburization during TPR synthesis...reduces the oxycarbide to Mo, which is easily carburized under reforming conditions. Pretreatment at 600 oC, was largely ineffective and it is...at atmospheric pressure [3]. They attributed this to competitive kinetics between oxidation and carburization , concluding that carburization

  7. Shipboard Coatings Developments, and Emerging Surface Technologies

    Science.gov (United States)

    2009-09-01

    LTCSS Process Traditional Carburization Traditional carburization is a thermochemical surface treatment that is commonly used to increase the...hardness and wear properties of steels Traditional carburization requires temperatures around 950°C, and in austenitic stainless steels this results in...residual compressive surface stress • Interstitially carburized layer is referred to as “S-phase” XRD on 316SS 309SS mag. 100x Ref: G. M. Michal, et al

  8. X-ray Diffraction as a Means to Assess Fatigue Performance of Shot-Peened Materials

    Science.gov (United States)

    2012-06-01

    5 3.1.1 The 4340 Steel .....................................................................................................6 3.1.2 Carburized ... Carburized 9310 Steel .........................................................................................9 3.2.3 Beta-STOA Titanium 6Al-4V...from the 4340 steel disks. ....................5 Figure 3. Residual stress and diffraction peak width data from the carburized 9310 steel disks

  9. Effects of Fuels on the Physical Properties of Nitrile Rubber O-Rings.

    Science.gov (United States)

    1983-09-01

    les effets d’une exposition i divers carburants et milanges de carburants, de garnitures d’itanchfit en caoutchouc au nitrile. Les propriets (resistance...avait 6ti couramment plong6e. Des 6prouvettes de caoutchouc ont t6 expos~es i un carburant commercial (gas-oil pr~lev6 en cours de raffinage) riche en

  10. Proposals for Solutions to Problems Related to the Use of F-34 (SFP) and High Sulphur Diesel on Ground Equipment Using Advanced Reduction Emission Technologies (Propositions de solutions aux problemes lies a l’utilisation de F-34 (SFP) et de diesel a haute teneur en soufre pour le materiel terrestre disposant de technologies avancees de reduction des emissions)

    Science.gov (United States)

    2008-09-01

    avancées de réduction des émissions (RTO-TM-AVT-ET-073) Synthèse Lors de sa réunion 2005, le Groupe de travail AC/112 de l’OTAN sur les carburants et les...émissions nécessitent l’utilisation de carburants à faible teneur en soufre (LSF). Le F-34 utilisé en vertu de la Politique du carburant unique de l’OTAN...Single Fuel Policy, ou SFP) est un carburant à haute teneur en soufre, en comparaison des carburants diesels européens et américains conformes aux

  11. Analisis Pengaruh Waktu pada Proses Karburasi Terhadap Kekerasan dan Mikrostruktur Baja Karbon Menengah NS-1045

    OpenAIRE

    Siahaan, Agus Pasaora

    2016-01-01

    Research on the effect of time on the carburizing process on hardness and microstructure of carbon steel Medium NS-1045 had been made at temperature 950 oC with variation of the time for 2 hours, 4 hours, 6 hours, and 8 hours. Carburizing type is Pack carburizing (Carburizing using solids). Carburizing media consists of mixed of active carbon from coconut shell charcoal powder mass of 50 grams and CaCO3 mass of 5 grams. and then been hardened by cooling oil medium SAE 40. Vi...

  12. Quels sont les enjeux d'une barrière de diffusion de carbure de titane entre le tungstène et le carbure de silicium, sur l'élaboration par dépôt chimique en phase vapeur, et sur les propriétés mécaniques du renfort filamentaire de SiC ?

    OpenAIRE

    Boiteau-Auvray, Sophie

    1997-01-01

    Les filaments de SiC sont obtenus par depot chimique en phase vapeur sur un substrat de W chauffe par effet Joule. Ces filaments peuvent etre utilises comme renforts dans des matrices d' alliage de titane. L' interposition d' une phase synthetique de TiC entre un substrat filamentaire de W et le depot de SiC a permis d' obtenir une stabilite thermochimique accrue du couple de diffusion. Les mecanismes conduisant a la protection chimique ont ete identifies. Une simulation numerique du depot de...

  13. INDUCTION PLASMA REACTIVE DEPOSITION OF TUNGSTENCARBIDE FROM TUNGSTEN METAL POWDER

    Institute of Scientific and Technical Information of China (English)

    X.L. Jiang; M.I. Boulos

    2001-01-01

    Experimental results are reported on the primary carburization reaction between the tungsten powder and methane in the induction plasma, and the secondary carburization of the deposit on substrate at high temperature. Optical microscopy and scanning electron microscopy were used to examine the microstructures of starting tungsten powder, carburized powder, and deposit. X-ray diffraction analysis, thermal gravimetric analysis and microhardness measurement were used to characterize the structures and properties of the powder and the deposit. It is found that the primary carburization reaction in the induction plasma starts from the surface of tungsten particles when the particles are melted. Tungsten particles are partially carburized inside the reactive plasma. Complete carburization is achieved through the secondary carburization reaction of the deposit on substrate at high temperature.``

  14. Nb K- and L3-edges XAFS study on the structure of supported Nb carbide catalyst

    Science.gov (United States)

    Ichikuni, N.; Yanagase, F.; Mitsuhara, K.; Hara, T.; Shimazu, S.

    2016-05-01

    Mesoporous silica SBA-15 supported NbC catalysts were prepared under reduced pressure of CH4-H2 gas in a closed circulating system. Nb K- and L 3-edges XAFS measurements revealed that small NbC cluster formed on SBA-15 support and gradual carburization process by lengthening the carburization temperature-maintaining period. Carburization degree of Nb species was clearly explained by using threshold energy shift of Nb L 3-edge XANES profile.

  15. Microstructure-Sensitive Modeling of High Cycle Fatigue (Preprint)

    Science.gov (United States)

    2009-03-01

    history ( carburization and shot peening) and resulting residual stresses are considered in the case of subsurface crack formation at primary inclusions...experimental responses for known microstructures. Effects of process history ( carburization and shot peening) and resulting residual stresses are considered...nonmetallic inclusions. 3. HCF Crack Formation in Carburized and Shot Peened Martensitic Gear Steel High strength low carbon martensitic gear steel is a

  16. Dynamic Microstructure Design Consortium

    Science.gov (United States)

    2011-03-23

    martensitic gear steels produced by QuesTek, including:  Development of novel strategies to couple process route (e.g., carburization and shot peening) with...McDowell, ―Modeling fatigue crack nucleation at primary inclusions in carburized and shot-peened martensitic steel,‖ Engineering Fracture Mechanics, 76...www.asme.org/terms/Terms_Use.cfm Modeling fatigue crack nucleation at primary inclusions in carburized and shot-peened martensitic steel Jixi Zhang

  17. JPRS Report, Science & Technology, USSR: Materials Science

    Science.gov (United States)

    2007-11-02

    Processes of Sintering and Carburizing of Powder Alloys (V.T. Vysotskiy, F.G. Lovshenko; METALLOVEDENIYE I TERMICHESKAYA OBRABOTKA METALLOV, No 1...achievements in this area. 20 PREPARATIONS UDC 621.785.5:621.762 Study of Possibility of Combining Processes of Sintering and Carburizing of Powder...Lovshenko, Mogilev Machine- Building Institute] [Abstract] A study was made of the influence of combining the processes of sintering and carburizing on

  18. Carbon Surface Modification for Enhanced Corrosion Resistance

    Science.gov (United States)

    2008-01-01

    2 R. Rayne,1 and R.A. Bayles1 1Chemistry Division 2SAIC Introduction: Case hardening by carburization has long been recognized to produce wear... carburization technique has been developed for intro- ducing carbon into stainless steel surfaces without formation of carbides.1,2 This surface modification...Michal, F. Ernst, H. Kahn, Y. Cao, F. Oba, N. Agarwal, and A.H. Heuer, “Carbon Supersaturation due to Paraequilibrium Carburization : Stainless

  19. High Strength P/M Gears for Vehicle Transmissions - Phase 2

    Science.gov (United States)

    2008-08-15

    carburizing grade (P/M 4620) but without the densification process of hot forging and another version of hot forged P/M 4620 but prepared for treatment after...gear optimization: The profile and leads obtained on the P/M 4620, Carburized and hardened, Standard test gear, after ausform finishing, at the end of...details are defined in table 1. Even though Phase I had indicated superior performance with the 4620 carburized and hardened alloy, this effort was

  20. Quench Press Hardening with Low Copper Plating. Management and Operation of the DoD Instrumented Factory for Gears

    Science.gov (United States)

    2007-11-02

    200 words) Copper plating is used as a carbon stop-off during the carburization and austenitization operations associated with the manufacture of...precision gears. The “Low Copper” project’s goals were to optimize the thickness of copper needed during carburization , and to eliminate the need to re... Carburizing , Copper Plating, SAE/AISI 9310H, Precision Gears, Press Quenching 15. NUMBER OF PAGES 92 16. PRICE CODE 17. SECURITY CLASSIFICATION 18

  1. Genes involved in the degradation of ether fuels by bacteria of the Mycobacterium / Rhodococcus group; Genes impliques dans la degradation des ethers carburants par des bacteries du groupe Mycobacterium/Rhodococcus

    Energy Technology Data Exchange (ETDEWEB)

    Beguin, P.; Chauvaux, S.; Miras, I. [Institut Pasteur, Unite Microbiologie et Environnement, URA 2172 CNRS, 75 - Paris (France); Francois, A.; Fayolle, F.; Monot, F. [Institut Francais du Petrole (IFP), Dept. Biotechnologie et Chimie de la Biomasse, 92 - Rueil-Malmaison (France)

    2003-08-01

    A cluster of genes encoding a cytochrome P-450 monooxygenase system involved in the utilisation of ethyl tert-butyl ether (ETBE) was cloned in Rhodococcus ruber IFP 2001. This cluster includes ethR, a putative regulator gene of the araC/xylS family; ethA, encoding a ferredoxin reductase; ethB, encoding a cytochrome P-450, ethC, encoding a ferredoxin; and ethD, which is required for the function of the monooxygenase system, but whose exact role is unknown. The ethRABCD cluster is flanked on either side by two identical copies of a class II transposon, which explains that it is lost at high frequency by homologous recombination when the strain is grown under non selective conditions. Two other, highly conserved clusters of eth genes were detected in the ETBE-utilizing strains Rhodococcus zopfii IFP 2005 and Mycobacterium sp. IFP 2009. In all cases, the eth locus is inserted in a different genomic context, suggesting that it may be transferred horizontally between different species and inserted at different sites in the genome. In addition, in R. zopfii IFP 2005, the downstream copy of the transposon carries a 117-bp (base pairs) deletion; in Mycobacterium sp. IFP 2009, the upstream copy is absent and the downstream copy is inserted 2771 bp closer to the ethRABCD cluster. (authors)

  2. 冲天炉熔炼优质高碳铁液及其增碳机理分析%Processes of Producing Qualified High-Carbon Gray Iron Melt with Cupola Furnace and Analysis on Its Carburizing Mechanism

    Institute of Scientific and Technical Information of China (English)

    杨文涛; 叶建

    2005-01-01

    冲天炉熔制高碳铁液有两种不同工艺途径,传统工艺是依靠加入足够比例的生铁获得,而现代工艺则通过焦碳使铁液充分渗碳获得.通过讨论并比较这两种不同工艺途径,并结合生产实践,提出了冲天炉稳定熔炼优质高碳铁液的工艺控制要点,阐述了冲天炉熔炼过程中铁液依靠焦碳增碳的机理.

  3. Algogroup: Towards a Shared Vision of the Possible Deployment of Algae to Biofuels Algogroup : vers une vision partagée du possible déploiement de la conversion des algues en carburants

    Directory of Open Access Journals (Sweden)

    Montagne Xavier

    2013-10-01

    Full Text Available A strong interest has been focused from several years on the algae pathway for energy production, especially for transportation fuels called third generation biofuel or G3 biofuel, and mainly from microalgae route, considering it could be a high potential alternative strategy for renewable energy and fuel production. Algae, and especially microalgae, present significant advantages compared with land resources, such as much higher productivity and lack of competition with food applications. Nevertheless, based on current knowledge, the production of an algae biomass for energy remains a difficult target to reach, due to the numerous existing hurdles such as the energetic yield and the economic positioning, without neglecting the environmental and societal aspect. Unlike first generation (GI and a few second generation biofuel (G2 processes, G3 biofuel processes are far from the industrialization step. In 2010, under the initiative of IFP Energies nouvelles, Airbus, Safran, EADS IW and the “Académie des Technologies”, launched a French national study of the potential of the algae sector as resources for the so called G3 biofuel production. This study was called “Algogroup” and led by IFP Energies nouvelles. The objective was to obtain a shared vision of the deployment possibilities. It led to the creation of this Algogroup task force with the previous partners, adding Sofiprotéol, INRA1, IFREMER1, CEVA1 and the Agrimip pole to combine all available knowledge and determine the responses which could be given to the existing questions. The Algogroup objective was to facilitate vision sharing between participating organisations and industrials on the technical improvements, the probabilities of success, the R&D needs and the development perspectives, while paying close attention to the obstacles which have to be alleviated to improve the positioning of the algae pathway. To reach this target, Algogroup has explored several axes, which enabled a thorough analysis of the potentials and limits of the technology: from the species selection to the harvesting (lipid extraction/recovery, including environmental and economical aspects. This paper focuses on some main aspects of the Algogroup study related to economical positioning and environmental terms, specially Life Cycle Analysis (LCA . A large share of the work was dedicated to microalgae, but since it was also considered important to examine the potential role of macroalgae, a specific analysis was conducted on this aspect. It has enabled the group to issue some recommendations such as a need for an integrated approach, need for tools to run comprehensive technico-economic assessments, including co products valorisation. Despite the limited amount of reliable information currently available on the algofuel sectors, especially in terms of environmental balance, numerous challenges still remain to be taken up to make these sectors credible and profitable, both technically, economically and environmentally. On the economic aspect the estimated costs for future microalgae biofuels remain in a very broad range from $2/Gal to $7/Gal. There remains great potential to decrease microalgae oil production costs, but this has to be considered very carefully given the large amount of underlying assumptions. Moreover, as yet underlined, microalgae biofuels are not currently being produced at a commercial scale, thus these are only potential scenarios, which will have to be confirmed. And finally, several technologies can be used to produce microalgae oil and location possibilities are proposed. Another key point is that, in a large majority of scenarios, the economic viability of the pathway relies on the valorisation of what one usually calls co-products. Valorisation of co-products is not considered a valid option in the long-term as no market identified today could absorb the quantities associated to a new fuel market. Besides, environmental studies have demonstrated that the energetic balance was not favourable at present, based on current processes, but the variation range of the results let some space for significant improvements. The balance of greenhouse gas emissions was favourable, and there also the variation range was very wide. As regards the other environmental impact categories, however, the uncertainties are too great to draw any conclusions. Because of the heterogeneity of approaches and results for the development of the algaepathway, we must bear in mind that without reliable and robust assessments of these sectors it will not be possible to direct their technical development sustainably. Macroalgae as a resource for biofuels production are very far from being a commercial reality, but do present some advantages such, for green algae, exhibiting several similarities with current GI and G2 feedstock, being producers of starch and unlignified cellulose. Nevertheless, they also contain other specific compounds. Red and brown macroalgae are currently the most produced species, but their composition calls for the development of new transformation processes. Although technically feasible at lab-scale, the economic viability of such processes is being endangered by the complexity of the processes involved and the numerous steps required as well as by non-technical issues such as competition with other markets like green chemistry. To have a true share of the future fuel mix, macroalgae production needs to be increase by a dozen- time fold. This increase should not be done without social acceptance or at the expenses of the environment. This issue was adressed for microalgae, but data on macroalgae are currently lacking to be able to conduct Life Cycle Assessment (LCA on this very specific environment. There are also additional problems to be taken into account, such as the lack of legislation or conflicts of usage with existing sea activities for example. Potential for high tonnage production seems real, but the challenge is to federate existing actors and new ones to build a new agro-industry. As a conclusion, no true leveraging option, leading to significant breakthroughs has really emerged as a short term solution, but wide spaces for significant improvement could be envisaged and more laboratory and pilot works have to be achieved before being able to move to a higher scale, leading to the first step toward industrial production. Depuis quelques années, un intérêt croissant pour la production d’algues, notamment les micro-algues, pour la production d’énergie a été observé, spécialement pour la production de biocarburants pour le transport routier et aérien, filière que l’on a coutume de qualifier de troisième génération. Les algues et spécialement les micro-algues affichent de nombreux avantages comparés aux ressources terrestres, comme par exemple une productivité nettement plus élevée et l’absence de compétition avec les filières alimentaires. Néanmoins, l’état actuel des connaissances ne conduit pas à penser qu’un développement de la culture de micro-algues pour la production d’énergie soit possible à court-moyen terme en raison de nombreux écueils à lever comme la balance énergétique, le positionnement économique sans oublier les aspects sociétaux et environnementaux. Contrairement aux filières de première génération et certaines filières de seconde génération, les biocarburants de troisième génération sont encore loin de l’industrialisation mais la nécessité de disposer d’une analyse commune et partagée par l’ensemble des acteurs de la filière est nécessaire. Ainsi, en 2010, à l’initiative d’IFP Energies nouvelles, Airbus, Safran, EADS IW, et l’Académie des Technologies ont mis en place un groupe d’étude national dédié à l’étude du potentiel de la filière micro-algues pour la production de biocarburants G3. Ce groupe, nommé Algogroup, piloté par IFP Energies nouvelles a eu comme objectif d’aboutir à une vision partagée d’un possible déploiement de la filière G3. Outre les membres fondateurs, Algogroup a aussi intégré les expertises dans le domaine, de Sofiprotéol, de l’INRA1, de IFREMER1, du CEVA1, de Agrimip ainsi que de nombreux autres laboratoires et industriels. Les travaux menés au sein d’Algogroup ont donc permis de collecter un ensemble de données sur le potentiel et les limites de la filière, la position des industriels et des laboratoires, sur les axes de recherches nécessaires à mettre en oeuvre pour permettre à la filière de se développer. La réflexion a été structurée selon différents thèmes. Les aspects technologiques : quelles souches, quel mode de culture, de récolte, les aspects économiques ainsi que les aspects environnementaux. Ce papier met l’accent sur les résultats d’Algogroup sur le positionnement économique et environnemental des micro-algues. En parallèle, une réflexion sur le potentiel des macro-algues a aussi été conduite au sein d’Algogroup. A ce jour, uniquement un nombre limité de données est accessible pour le secteur des “algocarburants” et s’engager dans la construction d’une telle filière est encore prématuré. Ainsi les résultats provenant d’Algogroup seront de précieuses contributions à l’élaboration d’une feuille de route Algocarburants. Sur un plan économique, les coûts estimés des futurs biocarburants fabriqués à partir de micro-algues s’étaleront dans une fourchette de 2 à 7 $/Gal. Cette situation laisse à penser qu’un large champ de possibilités est envisageable pour réduire le coût de production des huiles algales mais il faut toutefois rester très prudent car les scenarii conduisant à ces diminutions reposent sur des hypothèses qu’il faudra démontrer. En effet, ces scenarii considèrent des technologies et des localisations de production très variables. Un autre point clé des modèles économiques analysés est que dans une large majorité de ces scenarii, la viabilité économique repose sur la valorisation des coproduits. De telles options ne sont pas considérées comme acceptables sur le long terme en raison de l’incertitude qui règne sur les capacités d’absorption par le marché de ces produits lorsqu’ils seront liés à une production en grosses quantités de biocarburants. Considérant le volet environnemental, le travail a démontré que la balance énergétique n’était pas favorable, en se référant aux procédés explorés disponibles. Toutefois, les variations enregistrées laissent la place à des possibilités d’amélioration. Concernant les émissions de gaz à effet de serre, le bilan apparait favorable mais là aussi avec une plage de variations très large. Pour les autres aspects environnementaux, les incertitudes sont trop grandes pour conclure. Par ailleurs, en raison des très grandes hétérogénéités des approches et des résultats publiés pour le développement d’une filière micro-algues, il apparait que sans évaluation fiable et robuste du secteur, il n’est pas possible de considérer à ce jour ledéveloppement des techniques comme totalement compatibles avec les critères de durabilité. Pour les macro-algues, nous sommes encore très loin de pouvoir les considérer comme une ressources pour la production de biocarburants mais celles-ci présentent des avantages, comme pour le cas des algues vertes des similitudes avec les ressources utilisées pour les filières G1 ou G2. Concernant les algues brunes et les algues rouges qui sont aujourd’hui les espèces les plus produites, leurs compositions demandent le développement de nouveaux procédés pour leur valorisation. Bien que ces procédés soient faisables à l’échelle du laboratoire, la viabilité économique à grande échelle est à démontrer en raison de la complexité et du nombre d’étapes requis par ces procédés tout comme la compétition de cette filière avec les autres marchés, comme celui de la chimie verte. Par ailleurs, pour que les macro-algues puissent avoir un réel devenir dans le mix biocarburants, leur production doit être considérablement augmentée. Ce point ne peut être considéré sans avoir évalué l’impact sociétal et environnemental et aujourd’hui peu de données sont accessibles pour bien apprécier ces 2 volets. Enfin, il faudrait bien analyser tous les aspects législatifs liés au développement de culture à gros tonnages en mer. En dépit de ces aspects, le potentiel de production de grosses quantités semble réel. En conclusion, le travail effectué par Algogroup n’a pas fait émerger de réelles ruptures permettant d’envisager un développement à court moyen terme de la filière algocarburants mais des possibilités d’amélioration peuvent être envisagées. Ceci demande de poursuivre les travaux au niveau du laboratoire et à l’échelle du pilote avant de passer à une échelle préindustrielle.

  4. Theoretical study of silicon carbide under irradiation at the nano scale: classical and ab initio modelling; Etude theorique a l'echelle nanometrique du carbure de silicium sous irradiation: modelisation classique et ab initio

    Energy Technology Data Exchange (ETDEWEB)

    Lucas, G

    2006-10-15

    The behaviour of silicon carbide under irradiation has been studied using classical and ab initio simulations, focusing on the nano scale elementary processes. First, we have been interested in the calculation of threshold displacement energies, which are difficult to determine both experimentally and theoretically, and also the associated Frenkel pairs. In the framework of this thesis, we have carried out simulations in classical and ab initio molecular dynamics. For the classical approach, two types of potentials have been used: the Tersoff potential, which led to non satisfactory results, and a new one which has been developed during this thesis. This potential allows a better modelling of SiC under irradiation than most of the empirical potentials available for SiC. It is based on the EDIP potential, initially developed to describe defects in silicon, that we have generalized to SiC. For the ab initio approach, the feasibility of the calculations has been validated and average energies of 19 eV for the C and 38 eV for the Si sublattices have been determined, close to the values empirically used in the fusion community. The results obtained with the new potential EDIP are globally in agreement with those values. Finally, the elementary processes involved in the crystal recovery have been studied by calculating the stability of the created Frenkel pairs and determining possible recombination mechanisms with the nudged elastic band method. (author)

  5. Experimental Study on Pre-oxidization and Cyanide Carburizing of Refractory Gold Concentrate Containing High Sulphur Content%难浸高硫金精矿细菌预氧化--氰化浸出试验研究

    Institute of Scientific and Technical Information of China (English)

    范道焱; 董博文

    2013-01-01

    Biological oxidation-leaching experiments of refractory gold concentrate containing high sulfur was carried out.The relationships of leaching rate of gold with the process parameter of pulp density,pH value,the reaction temperature,grinding fineness,oxidation time were studied by experiment,and the oxidated liquid was under the reuse treatment.Under the optimal process conditions,including slurry concentration of 16%,the pH value 1.2~1.4,the reaction temperature was 40 ℃,grinding fineness of less than 0.043 mm accounted for more than 94.8%,the oxidation time condition for 8 days.The ore sample was dealed with the bacterial oxidation processing technology,the oxidation rate of sulfur reached 86.0%,the leaching rate of gold was improved from 23.4%to 92.6%.%针对甘肃亚特含高硫难浸金精矿开展了生物预氧化-氰化浸出试验研究,考察了细菌预氧化过程中矿浆浓度、pH值、反应温度、磨矿细度和氧化时间等参数条件对浸出的影响,并对氧化后液进行回用处理。结果表明,在矿浆浓度为16%、pH值为1.2~1.4、反应温度为40℃、磨矿细度<0.043 mm占94.8%以上以及氧化时间为8 d的条件下,采用细菌预氧化处理技术对矿样进行处理,硫氧化率达86.0%,金浸出率由直接氰化浸出率的23.4%提高到92.6%。

  6. Elaboration of silicon carbides nano particles (SiC): from the powder synthesis to the sintered ceramic; Elaboration de ceramiques nanostructurees en carbure de silicium (SiC): de la synthese de poudre a la ceramique frittee

    Energy Technology Data Exchange (ETDEWEB)

    Reau, A. [CEA Saclay, Dept. des Materiaux pour le Nucleaire (DEN/DANS/DMN/SRMA), 91 - Gif-sur-Yvette (France)

    2008-07-01

    Materials for the reactor cores of the fourth generation will need materials supporting high temperatures with fast neutrons flux. SiC{sub f}/SiC ceramics are proposed. One of the possible elaboration process is to fill SiC fiber piece with nano particles SiC powder and to strengthen by sintering. The aim of this thesis is to obtain a nano structured SiC ceramic as a reference for the SiC{sub f}/SiC composite development and to study the influence of the fabrication parameters. (A.L.B.)

  7. Low-carbon Bainitic Steel Carburizing and Its Application in Car Gear%低碳贝氏体钢渗碳工艺及在轿车齿轮上的应用

    Institute of Scientific and Technical Information of China (English)

    李新生; 梁淑荣

    2000-01-01

    对低碳贝氏体钢的渗碳工艺、显微组织、力学性能、淬火变形进行了研究.结果表明,此钢渗碳工艺性能良好,渗碳层组织理想,力学性能优良.采用渗碳气冷淬火,使轿车齿轮淬火变形比20CrMnTi钢的明显减小.

  8. 42CrMo钢渗碳淬火齿轮弯曲疲劳极限快速测定%Rapid Assay Analysis of Bending Load Capacity Limit on 42CrMo Carburized-quenched Gear

    Institute of Scientific and Technical Information of China (English)

    赵富强; 王铁

    2011-01-01

    针对42CrMo钢生产新齿轮的需要,进行了齿轮弯曲疲劳强度试验.在对该材料进行化学成分分析和硬度检测后,提出基于LOCATI方法进行双齿脉动加载试验.根据试验所得数据,按统计学原理,拟合出S-N曲线,并获得置信度为95%、可靠度为95%的弯曲疲劳极限应力值.为该材料齿轮的弯曲疲劳可靠性设计、有限寿命设计提供了真实的试验依据.%In order to decide whether 42CrMo steel could be selected as gear-material, tests on the bending fatigue strength of gears are analyzed. After taking chemical composition analysis and hardness test of 42CrMo steel, the pulsating loading test based on the Locati method is proposed. Then in terms of the principle of statistics, a fitted N-S curve is obtained by processing the data gained from the test and the bending fatigue limit is achieved with a 95% of both confidence and reliability. They provide the experimental basic data for the gear's reliability design and limited life design.

  9. Dispersants in an organic medium: synthesis and physicochemical study of dispersants for fuels and lubricants; Dispersants en milieu organique: synthese et etude physicochimique de dispersants pour carburants et lubrifiants

    Energy Technology Data Exchange (ETDEWEB)

    Dubois-Clochard, M.C.

    1998-11-19

    Carbonaceous deposits coming from the fuel and the lubricant are known to form over time at critical locations in an engine. In general, the deposits have an adverse effect on four functional areas which are the fuel metering system, the intake system, the lubrication system and the combustion chambers. These deposits can degrade vehicle performance and drive-ability, reduce fuel economy, increase fuel consumption and pollutant emissions and may lead to the destruction of the engine. In order to remedy these problems, detergent-dispersant additives are used in fuels and lubricants to avoid or decrease deposit adhesion on metallic surfaces and prevent from deposit aggregation. These products are mainly polymer surfactants and in this work, poly-iso-butenyl-succinimide of different structures have been studied. Firstly, 'comb like' polymers have been synthesized. Then they have been compared to classical di-bloc additives in terms of performance and action mechanism. These additives are adsorbed from their hydrophilic polyamine part on the acidic functions of the carbon black surface chosen as an engine deposit model and on the aluminium oxide function of an aluminium powder chosen as an engine wall model. The adsorption increases with temperature on the two solids. Their affinity with the solid surface increases with the length of the hydrophilic part. In the same way, changing the di-bloc structure for a comb like one lead to a better adsorption. At low concentration, it has been shown that the adsorption phenomenon was irreversible, due to the polymer structure of the polar part. Depending on the space required by the hydrophilic part on the solid surface, a more of less dense monolayer is formed. At higher concentrations, an important increase of the adsorbed amount appears. This phenomenon is totally reversible showing that the interactions additive / additive are weak. The dispersing efficiency of a comb like structure is better than a di-bloc one as the hydrophilic parts are forced to huddle together, decreasing the solid surface required and enhancing the stretching of hydrophobic parts. (author) 136 refs.

  10. Etude des effets d'irradiation dans le polytype cubique du carbure de silicium par les techniques spectroscopiques de photoluminescence et de résonance paramagnétique électronique.

    OpenAIRE

    Lefevre, Jérémie

    2008-01-01

    This experimental work involved the study of point defects induced by electron irradiation in the crystal structure of cubic silicon carbide (SiC) using spectroscopic techniques at low temperature photoluminescence (LTPL) and electron spin resonance (ESR) . The first of these measurement tools has allowed to estimate the energy seujl displacement in the silicon sub-network and then analyze the thermal stability of radiation defects in the field of low temperatures (10 - 300K) then range of hi...

  11. Développement d'un réacteur intensifié en Carbure de Silicium pour la transposition en continu de réactions d'hydrosilylation

    OpenAIRE

    Fustier, Céline

    2012-01-01

    De nos jours, les limites du réacteur batch, outil conventionnel de l'industrie de la chimie fine, en termes de transfert thermique et de transfert de matière, conduisent à envisager le passage en continu de réactions dont les problématiques d'exothermie et de rapidité rendent leur industrialisation difficile. Les réacteurs-échangeurs compacts sont un exemple de technologies intensifiées continues alliant les performances d'un échangeur de chaleur couplées à un bon mélange ainsi qu'à un compo...

  12. 提高渗碳淬火和氮碳共渗件质量的途径%Improvement on the Quality of Gas Carburized-quenched and Gas Nitrocarburized Parts

    Institute of Scientific and Technical Information of China (English)

    李志义

    2007-01-01

    分析了气体渗碳淬火件渗层中非马氏体组织的控制,从气源选择,渗碳机制,天然气质量及其净化,甲醇、氮气和液氨的质量控制,淬火冷却及回火,毛坯的预备热处理等方面论述了提高渗碳淬火件质量的措施,简述了氮碳共渗质量的控制和金相检验方法.

  13. Elaboration of massive silicon carbide monocrystals for power electronics applications. Reduction of the density of defects; Elaboration de monocristaux de carbure de silicium massifs pour l'electronique de puissance - reduction de la densite de defauts

    Energy Technology Data Exchange (ETDEWEB)

    Moulin, C. [CEA Grenoble, LETI, 38 - Grenoble (France)

    2001-07-01

    Thanks to its exceptional physical properties, SiC is a semiconductor material of prime importance for average and high power, high frequency and high temperature electronic applications. However, the SiC technology requires large diameter substrates (50 mm) with a density of micro-defects (micro-pipes or micro-tubes) lower than 10/cm{sup 2}. The present study deals with the reduction of the defects density in massive SiC crystals elaborated using a modified version of Lely's method. The method consists in the sublimation of a SiC powder and to the condensation of vapor species onto a SiC monocrystal germ. A thermal gradient is established between the powder and the germ which favors the transport of species from the powder to the germ. A study of the crystals characteristics and of the growth properties has permitted to identify the sensible parameters and to significantly improve the quality of the obtained crystals. Short note. (J.S.)

  14. The automobile of the future: engine technologies and automotive fuels developed by IFP; l'automobile du futur: les technologies moteurs et carburants developpes par l'IFP

    Energy Technology Data Exchange (ETDEWEB)

    Appert, O.; Pinchon, Ph.

    2004-07-01

    In front of the challenges of climate change and depletion of petroleum reserves, in front of the continuous strengthening of pollution regulations applied to automobile (Euro IV and V) and the advances of R and D, several ways of research can be explored to answer the mobility needs of the coming decades. The IFP takes stock of these topics in this press kit which comprises 11 documents: the synthesis of O. Appert and P. Pinchon's talk about 'the cleaner and multi-energies automobile of the future', the slides of this presentation, the future evolutions of automobiles motorizations, the long-term evolutions of engines/fuels (brief for the Panorama 2004 colloquium), diesel fuel in the USA (brief for the Panorama 2004 colloquium), bio-fuels in Europe (brief for the Panorama 2004 colloquium), diesel pollution abatement: efficient results from the IFP's diesel combustion process 'NADI'(TM), the presentation of the IFP scientific meeting of September 22-23, 2004 'which fuels for low CO{sub 2} engines?', the strategic positioning of IFP in the world energy and environmental context, the brochures 'IFP engines and fuels: a competitive advantage' and 'innovating for a sustainable development in the domain of energy'. (J.S.)

  15. Opening talk given by M. Dominique Maillard at the professional colloquium of the French federation of fuels; Discours d'ouverture prononce par M. Dominique Maillard au colloque professionnel de la Federation francaise des combustibles et des carburants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This talk, given by D. Maillard, general director of energy and raw materials, presents first the 2004 world situation of petroleum products in terms of prices and production capacity and the role played by investment funds in this situation. Then, he proposes some short-term actions to be implemented: encouraging investment efforts in exploration-production, preservation of strategic stocks, influencing the consumers behaviour in order to reduce the demand, assigning exceptional financial helps to professionals whose activity is threatened by the rise of petroleum products price. In the last part of his talk, D. Maillard wants to reassure the petroleum products retailers about the evolutions of their profession in this context of prices inflation. The government will harmonize the tax discrepancies between natural gas and gas oil and will ensure the equilibrium between the different forms of trade in the petroleum products sector in order to maintain a sound competition between the small and big retailers. (J.S.)

  16. Influence of plasma nitro carburization on fatigue properties in a 4340 steel with different microstructure; Infuencia da nitrocarbonetacao a plasma nas propriedades de fadiga de um aco 4340 com diferentes microestruturas

    Energy Technology Data Exchange (ETDEWEB)

    Ranieri, A.; Hashimoto, T.M. [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia (FEG); Baggio-Scheid, V.H.; Abdalla, A.J., E-mail: abdalla@ieav.cta.b [Departamento de Ciencia e Tecnologia Aeroespacial (IEAv/DCTA), Sao Jose dos Campos, SP (Brazil). Inst. de Estudos Avancados

    2010-07-01

    Three different routes of heat treatments were applied in samples of 4340 steel in order to modify the microstructures and mechanical properties. After this initial treatment was applied a plasma nitrocarburizing thermochemical treatment in a part of the samples, forming a layer of nitride (Fe{sub 4}N and Fe{sub 3}N{sub 2}) of about 10{mu}m, with high hardness, in order to improve the surface characteristics. The layer and microstructure were characterized with X-ray analysis, optical microscopy, confocal laser scanning and hardness test by microindentation. Tensile and fatigue tests show the influence of microstructure formed on the mechanical properties, the microstructure predominantly bainitic phase showed a better combination of ductility, toughness and fatigue life. After treatment nitrocarburizing was observed the effect of tempering, with a reduction in hardness of substrate and tensile strength. In steel with martensitic microstructure the fatigue life decreases. (author)

  17. Densification of silicon and zirconium carbides by a new process: spark plasma sintering; Densification des carbures de silicium et de zirconium par un procede innovant: le spark plasma sintering

    Energy Technology Data Exchange (ETDEWEB)

    Guillard, F

    2006-12-15

    Materials research for suitable utilization in 4. generation nuclear plants needs new ways to densify testing components. Two carbides, silicon and zirconium carbide seems to be the most suitable choice due to their mechanical, thermal and neutron-transparency properties against next nuclear plant specifications. Nevertheless one main difficulty remains, which is densifying them even at high temperature. Spark Plasma Sintering a new metal-, ceramic- and composite-sintering process has been used to densify both SiC and ZrC. Understanding bases of mass transport mechanisms in SPS have been studied. Composites and interfaces have been processed and analyzed. This manuscript reports original results on SiC and ZrC ceramics sintered with commercial powder started, without additives. (author)

  18. Irradiation effects and diffusion of fission products (cesium and iodine) in silicon carbide; Effets d'irradiation et diffusion des produits de fission (cesium et iode) dans le carbure de silicium

    Energy Technology Data Exchange (ETDEWEB)

    Audren, A

    2007-03-15

    Silicon carbide is envisaged as a cladding material for the nuclear fuel in the fourth generation reactors. The aim of this work is to study the capacity to retain fission products and the structure evolution of this material under the combined effects of temperature and irradiation. The low energy ion implantations and the incorporation of stable analogues of fission products (Cs and I) in single crystalline 6H-SiC samples were performed by using the ion implanter or the accelerator of the CSNSM. The high energy heavy ion irradiations were made at GANIL. The evolution of the implanted ion profiles and the crystal structure were studied by RBS and Channeling. Complementary information were obtained by using the UV-visible absorption spectroscopy. The low energy ion implantations at room temperature induce a fast structural damage in the crystal. On the other hand, it is possible to attain a small disorder rate in the crystal during implantation by increasing the implantation temperature (600 C). The high energy heavy ion irradiations do not damage the SiC crystals. On the contrary, they cause an annealing of the disorder created by the low energy implantations. The implanted ions (I) do not diffuse during low or high energy ion irradiations at room temperature and at 600 C. However, a diffusion of Cs ions was observed during a post-implantation annealing at 1300 C. At this temperature, the crystal which had an extended amorphous layer starts to recover a single-crystal structure. (author)

  19. To break away from fossil fuels : a contribution to solve climatic change and energy security for Quebec; S'affranchir des carburants fossiles : une contribution a la lutte aux changements climatiques et a la securite energetique du Quebec

    Energy Technology Data Exchange (ETDEWEB)

    Bonin, P.; Seguin, H.; Waridel, L.

    2006-06-15

    In response to growing energy demands, Quebec has proposed the construction of 3 deep water terminals to accommodate methane tankers which transport liquefied natural gas (LNG). This paper focused on the proposed Gros Cacouna Port project in the St. Lawrence Seaway which is currently under study and subject to approval. Equiterre, questioned the energy security aspect of the proposal and argued that increasing Quebec's reliance on increasingly expensive energy would decrease energy security. In addition, importation of LNG would bring a clear exit of capital outside the province. Equiterre also argued that reliance on fossil fuels should be decreased in order to mitigate greenhouse gas emissions which contribute to climate change. The organization questioned whether the economic and social need for the proposed project justifies a greater dependency on fossil fuels and the associated impact on the environment and fragile ecosystems of the St. Lawrence. It was suggested that alternative solutions such as renewable energy sources and energy efficiency should be explored in order to promote sustainable development, increase energy security and reduce greenhouse gases. Equiterre argued that Quebec can and must decrease, and even eliminate, its dependence on fossil fuels, including natural gas, for Quebec's economic, social and environmental well-being. For these reasons, Equiterre recommended that the proposed project be rejected, particularly since the project proponents failed to show the real impact that the project would have on Quebec markets. 72 refs., 10 tabs., 21 figs.

  20. Special Features of the Carbonitriding of Parts of Instrument Bearings Designed for Extreme Service Conditions

    Science.gov (United States)

    Smirnov, A. E.; Shevchenko, S. Yu.; Shchipunov, V. S.; Kunyaev, V. E.; Seval'nev, G. S.

    2016-09-01

    A study is made of complexly alloyed steel 8Kh4V9F2-Sh, which is used for fabricating parts of engineering bearings operating under extreme conditions. Vacuum processes are shown to be preferable to gas carburizing for hardening the races of precision bearings. Vacuum carburizing is shown to be an effective technique for forming quality diffusion layers.

  1. Advanced Processing of Hollow Sphere Foams

    Science.gov (United States)

    2007-11-02

    composition is close to that of 405 stainless. Carburization in CO/CO2 atmosphere followed by heat treatment produces foams of either 410 or 420 type...after carburization . A sample with 0.5 wt% carbon at a relative density of 15% indicated a yield strength of 16 MPa. Specific strengths of the foams were

  2. S&T Efforts for Navy Corrosion Control

    Science.gov (United States)

    2010-11-01

    compressive surface stress Interstitially carburized layer is referred to as “S-phase” 309SS mag. 100x XRD on 316SS Ref: G. M. Michal, et al., Acta...temperature Inhibits carburization Activation via HCl thins oxide layer and allows carbon diffusion to substrate Corrosion Resistant Surface Treatment

  3. A Weakest-Link Approach for Fatigue Limit of 30CrNiMo8 Steels (Preprint)

    Science.gov (United States)

    2011-03-01

    used to predict the fatigue limit of notched and multiaxially loaded specimens of carburized steel [7]. The model was shown to be effective in... Carburized Steel 16mncrs5," Fatigue and Fracture of Engineering Materials and Structures, 28, pp. 983-995. [8] Bomas, H., Linkewitz, T., and Mayr, P., 1999

  4. 渗碳

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Carbo-Austempering - A new wrinkle?;Carburization Resistance of Austenitic Alloys in CH{sub}4-CO{sub}2-H{sub}2 Gas Mixtures at Elevated Temperatures;Causes of variability in gear fatigue testing; Change of the structure and mechanical properties of carburized layer as a result of its plastic deformation

  5. Microstructure and properties of borocarburized and laser-modified 17CrNi6-6 steel

    Science.gov (United States)

    Kulka, M.; Makuch, N.; Pertek, A.; Piasecki, A.

    2012-06-01

    Two-step process: carburizing followed by boriding was applied to the formation of borocarburized layers. The boride layer formed on the substrate of changeable chemical and phase composition (e.g. borocarburized layer) was called "gradient boride layer", in contrast to "typical boride layer", formed on the substrate of constant chemical and phase composition. Until now, the typical heat treatment of borocarburized layer consisted of treatment through hardening: quenching in oil and low-temperature tempering. In this paper, instead of treatment through hardening, laser-heat treatment was employed. The properties of such layer were compared to the properties of typical carburized layer. Three zones characterized the microstructure of laser-modified borocarburized layer: iron borides (FeB+Fe 2B) of modified morphology, hardened carburized zone (heat affected zone) and carburized layer without heat treatment. X-ray microanalysis indicated the increased boron concentration close to the surface due to the occurrence of a mixture of FeB and Fe 2B borides. Near to the hardened carburized zone, Fe 2B phase occurred in the laser-modified boride zone. Laser-heat treated borocarburized layer was characterized by higher microhardness at the surface than that obtained in case of carburized layer. It was caused by the iron borides (FeB+Fe 2B) occurrence at the surface, as a consequence of boriding process. However, the carburized layer was characterized by considerably larger hardened zone. Higher abrasive wear resistance, but lower low-cycle fatigue strength in comparison with the carburized layer, characterized the gradient boride layer formed by borocarburizing and laser surface modification. The indentation craters obtained on the surface of laser-heat treated borocarburized layer revealed sufficient cohesion (HF3 standard). The use of laser-modified borocarburized layers may be advantageous under conditions of high abrasive wear of mating parts. In case of parts, which

  6. Replacement of Chromium Electroplating on Helicopter Dynamic Components Using HVOF Thermal Spray Technology

    Science.gov (United States)

    2009-11-01

    PH3-8Mo stainless steel, carburized 9310 gear steel and 7075Al, and coated with EHC (baseline), WC- 17Co, WC-10Co-4Cr, Tribaloy 400, and duplex T400/WC...150-170 thousands of pounds per square inch [ksi]), PH13- 8Mo, carburized 9310, 7075Al • Coatings: EHC baseline, WC-17Co, WC-10Co-4Cr, Tribaloy 400...Specimen preparation: Shot peen to AMS 2432 under computer control to 100% surface coverage using 8-10A, S110, wrought steel shot. Carburized 9310 steel

  7. Novel Processing for Creating 3D Architectured Porous Shape Memory Alloy

    Science.gov (United States)

    2013-03-01

    prevents inter-diffusion of Fe into the NiTi matrix. Previously, steel spaceholders were carburized before processing. In this case, high carbon steel...Also, 5.3 wt% Nb powder is blended with the NiTi powder matrix to form small amounts of the eutectic phase. The tubes were carburized and sensitized...by carburizing for 960°C for 4 hr packed in graphite under flowing argon. The NiTi+Nb powder blend was then packed around the frame and cold

  8. 渗碳

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    [ 篇名 ] A quantitative alternative to HV test based on hardness-thermal diffusivity carbon-dependent correlation applied to CO{sub}2-1aser annealed or quenched carburized steel,[ 篇名 ] A quantitative alternative to the Vickers hardness test based on a correlation between thermal diffusivity and hardness - applications to laser-hardened carburized steel,[篇名] Air-cooled fans reduce maintenance issues,[ 篇名 ] An evaluation of atmosphere and vacuum carburizing methods for the heat treatment of gears,[篇名] Application of natural gas to vacuum carburizing,[篇名] ASSET, an information system for alloy corrosion in high temperature gases,[ 篇名 ] Bending fatigue life analysis of carburized components using strain life and fracture mechanics approaches。

  9. Diffusion aluminide coatings for internal surface of rhenium- and rhenium-ruthenium-containing single-crystal superalloys turbine blades: Part I

    Science.gov (United States)

    Mubovadzhyan, S. A.; Galoyan, A. G.

    2012-09-01

    Process of formation rhenium or refractory carbides based diffusion barrier layer (coating) on internal surface of rhenium- and rhenium-ruthenium-containing single-crystal high-temperature alloys (superalloy) turbine blades, prior to diffusion aluminide coating deposition, is studied. It is shown that diffusion barrier layer is preventing deleterious secondary reaction zone formation under aluminide coating during long-term high-temperature operation. The kinetics of powder carburizing process of rhenium- and rhenium-ruthenium-containing high-temperature alloys is investigated, and conditions for carburizing these alloys are determined. The phase composition of the surface layer after carburizing is studied, and the effect of the fractional composition of a carbon-based powder mixture on the carburizing rate is determined.

  10. HIGH-TEMPERATURE VACUUM CEMENTATION – THE RESERVE TO REDUCE THE ENERGY INTENSITY OF MANUFACTURE AND IMPROVE THE QUALITY OF TRANSMISSIONS GEARWHEELS OF HIGH-ENERGY MACHINES

    Directory of Open Access Journals (Sweden)

    A. A. Shipko

    2016-01-01

    Full Text Available Results of research of influence of high-temperature vacuum chemical heat treatment on the amount of grain structural steels are presented. The efficiency of hereditary fine-grained steel for high temperature vacuum carburizing are shown.

  11. Influence of Heat Treatment on Mercury Cavitation Resistance of Surface Hardened 316LN Stainless Steel

    Energy Technology Data Exchange (ETDEWEB)

    Pawel, Steven J [ORNL; Hsu, Julia [Massachusetts Institute of Technology (MIT)

    2010-11-01

    The cavitation-erosion resistance of carburized 316LN stainless steel was significantly degraded but not destroyed by heat treatment in the temperature range 500-800 C. The heat treatments caused rejection of some carbon from the carburized layer into an amorphous film that formed on each specimen surface. Further, the heat treatments encouraged carbide precipitation and reduced hardness within the carburized layer, but the overall change did not reduce surface hardness fully to the level of untreated material. Heat treatments as short as 10 min at 650 C substantially reduced cavitation-erosion resistance in mercury, while heat treatments at 500 and 800 C were found to be somewhat less detrimental. Overall, the results suggest that modest thermal excursions perhaps the result of a weld made at some distance to the carburized material or a brief stress relief treatment will not render the hardened layer completely ineffective but should be avoided to the greatest extent possible.

  12. Etude du revenu de l'acier z 10 CDNbV0902 (type 9% Cr, 2% Mo + Nb,V) envisage pour la realisation de certains composants des reacteurs a neutrons rapides

    Science.gov (United States)

    Pelletier, M.; Vilar, R. M.; Cizeron, G.

    1982-02-01

    Après trempe depuis 1100°C, l'acier étudié est formé de ferrite stable à haute température et de martensite. Au cours de revenus anisothermes, la phase martensitique est le siège de la précipitation successive de carbures des types M 3C, M 7C 3 et M 2C, ces deux derniers étant responsables d'un durcissement secondaire significatif. Aux températures plus élevées, ces carbures se dissolvent tandis qu'apparaissent des carbures des types M 23C 6 et M 6C. La phase ferritique initialement sursaturée est, par ailleurs, le siège d'une précipitation de carbures des types M 2C et M 23C 6.

  13. Effects of WC Particle Size and Co Content on the Graded Structure in Functionally Gradient WC-Co Composites

    Directory of Open Access Journals (Sweden)

    Yuan Yigao

    2016-01-01

    Full Text Available Functionally gradient WC-Co composites having a Co depleted surface zone and not comprising the h phase can be manufactured via carburizing process. During carburizing, besides carburizing process parameters, the microstructural parameters of WC-Co materials, such as WC grain size and Co content, also have significant influences on the formation of Co gradient structure. In this study, the effects of WC particle size and Co content on the gradient structure within gradient hardmetals have been studied, based on a series of carburizing experiments of WC-Co materials with different WC particle sizes and cobalt contents. The results show that both the thickness and the amplitude of the gradients within gradient WC-Co materials increase with increasing initial WC particle size and Co content of WC-Co alloys. The reason for this finding is discussed.

  14. Strengthening of oxidation resistant materials for gas turbine applications. [treatment of silicon ceramics for increased flexural strength and impact resistance

    Science.gov (United States)

    Kirchner, H. P.

    1974-01-01

    Silicon nitride and silicon carbide ceramics were treated to form compressive surface layers. On the silicon carbide, quenching and thermal exposure treatments were used, and on the silicon nitride, quenching, carburizing, and a combination of quenching and carburizing were used. In some cases substantial improvements in impact resistance and/or flexural strength were observed. The presence of compressive surface stresses was demonstrated by slotted rod tests.

  15. Summary of HCAT Helicopter Dynamic Components Project

    Science.gov (United States)

    2008-02-01

    PH13-8Mo H1050, 9310 carburized , 7075 T73 Al Coatings – EHC, WC-Co, WC-CoCr, T400, T400+WC-Co (Al only) Fatigue (smooth bar), R=0.1 Fretting fatigue...so slower to damage and initiate cracks klegg@rowantechnology.com G85 – 9310 carburized Coating Thickness Ni Sublayer 0 24 72 120 216 312 360

  16. Nanostructure-based Processes at the Carbonizing Steels

    Directory of Open Access Journals (Sweden)

    L.I. Roslyakova

    2015-12-01

    Full Text Available The studies of nanostructure-based processes carburizing steels showed that oxidizing atmosphere when carburizing steel contains along with carbon dioxide (CO2 + C = 2CO molecular and atmospheric oxygen (O2 + 2C = 2CO; O + C = CO released from the carbonate ВаСОз during its thermal dissociation. Intensive formation of CO provides high carbonizing ability of carbonate-soot coating and steel.

  17. 差动齿轮

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A novel class of intelligent power-assist systems based on differential CVT;Development of high-strength case hardening steel;Development of torque sensing LSD with cone clutch aiming at smaller size and lighter weight;Effect of Core Hardness and Case Depth on Low-Cycle-Impact-Fatigue Property in Carburized Steel;Effect of core hardness and ECD on low-cycle-impact-fatigue property in carburized steel……

  18. Surface processing to improve the fatigue resistance of advanced bar steels for automotive applications

    Directory of Open Access Journals (Sweden)

    David K. Matlock

    2005-12-01

    Full Text Available With the development of new steels and processing techniques, there have been corresponding advances in the fatigue performance of automotive components. These advances have led to increased component life and smaller power transfer systems. New processing approaches to enhance the fatigue performance of steels are reviewed with an emphasis on carburizing and deep rolling. Selected examples are presented to illustrate the importance of the base steel properties on the final performance of surface modified materials. Results on carburized gear steels illustrate the dependence of the fatigue behavior on carburizing process control (gas and vacuum carburizing, alloy additions and microstructure. The importance of retained austenite content, case and core grain size as controlled by processing and microalloy additions, extent of intergranular oxidation, and the residual stress profile on fatigue performance is also illustrated. Specific recent results on the use of microalloying elements (e.g. Nb and process history control to limit austenite grain growth at the higher carburizing temperatures associated with vacuum carburizing are highlighted. For crankshaft applications, deep rolling is highlighted, a process to mechanically work fillet surfaces to improve fatigue resistance. The influence of the deformation behavior of the substrate, as characterized by standard tensile and compression tests, on the ability to create desired surface properties and residual stress profiles will be illustrated with data on several new steels of current and future interest for crankshaft applications.

  19. Report of the results of the fiscal 1997 regional consortium R and D project. Regional consortium energy field / Development of the plasma use surface treatment process by in-situ control (first fiscal year); 1997 nendo chiiki consortium kenkyu kaihatsu jigyo. Chiiki consortium energy bun`ya / in-situ seigyo ni yoru plasma riyo hyohi shori process no kaihatsu (daiichi nendo) seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    The paper described the fiscal 1997 result of the development. To know of in-plasma phenomena such as carburization and nitriding, a basic plasma experimental device was fabricated for quantitative measurement of reaction activity species. For the study of reaction control between plasma and substrate, a rotary analyzer type ellipsometer was fabricated as a method to detect composition and thickness of the deposit on the substrate surface. For He gas cooling after carburization and hardening, basic specifications for He gas refining/circulating system were confirmed. For perfect non-hazardous processing of exhaust gas from plasma carburization furnace, conducted was the thermodynamic computation of the process. Priority in order of the functions to be possessed as specifications for basic design of mini plant is plasma carburization, He gas cooling, and in-situ measurement. To make the most of the plasma use surface treatment as substitutes for expensive alloy elements, sliding parts/die-cast mold raw materials were carburized to measure the hardness. The Cr carbide coating technology by plasma CVD is also under study as an application example except carburization. 47 refs., 59 figs., 31 tabs.

  20. Development and validation of an Eulerian model towards the simulation of fuel injection in internal combustion engines; Developpement et validation d'un modele eulerien en vue de la simulation des jets de carburants dans les moteurs a combustion interne

    Energy Technology Data Exchange (ETDEWEB)

    Truchot, B.

    2005-12-15

    The objective of this work is to develop an Eulerian two phase model to improve the prediction of fuel injection in internal combustion engines, particularly the dense liquid zone close to the nozzle. Lagrangian models, usually used in engine simulations, are based on the assumption of dispersed two phase flows with low liquid volume fraction, which is not fulfilled in the case of direct injection engine technology. Different Eulerian approaches are available in the literature. Physical phenomena that occur near the nozzle and characteristics of each model lead to the choice of a two fluids two pressures model. Several open terms appear in the equations of the model: exchange between the two phases and turbulent correlations. Closures of exchange terms are based on the spherical droplets hypothesis while a RANS approach is adopted to close turbulent correlations. This model has been integrated in the IFP CFD code, IFP-C3D. Several numerical tests and analytical validations (for single and two phase flows) have been then carried out in order to check the correct implementation of equations and the predictivity of the model and closures. Modifications in the turbulent model of the gas have required validations in both the gas phase (flow behind a sudden enlargement) and the liquid phase (pure liquid injection). A two phase mixing layer has been then used to validate the whole model. Finally, injection tests have been achieved under realistic conditions (similar to those encountered in automotive engines) in order to check the feasibility of engine computations using the developed Eulerian approach. These tests have also allowed to check the compatibility of this approach with the specificities of engine simulations (especially mesh movement). (author)

  1. Low temperature oxidation, co-oxidation and auto-ignition of olefinic and aromatic blending compounds: Experimental study of interactions during the oxidation of a surrogate fuel; Oxydation, co-oxydation et auto-inflammation a basses temperatures d'alcenes et aromatiques types: etude experimentale des interactions au sein d'un carburant-modele

    Energy Technology Data Exchange (ETDEWEB)

    Vanhove, G.

    2004-12-15

    The low-temperature (600-900 K) and high-pressure (5-25 bar) oxidation and auto-ignition of the three position isomers of hexene, of binary mixtures of 1-hexene, toluene and iso-octane, and of a surrogate fuel composed of these three compounds were studied in motor conditions using a rapid compression machine. Auto-ignition delay times were measured as long as intermediate products concentrations during the delay. The results show that the oxidation chemistry of the hexenes is very dependent on the position of the double bond inside the molecule, and that strong interactions between the oxidation mechanisms of hydrocarbons in mixtures can occur. The data obtained concerning the surrogate fuel give a good insight into the behaviour of a practical gasoline after an homogeneous charge compression. (author)

  2. Deployment of hydrogen supply chain for fuel market in 2050: Design and development of a decision support system for scenarios analysis; Deploiement de la chaine logistique de l'hydrogene pour le marche des carburants en 2050: Conception et developpement d'un outil d'optimisation pour l'analyse de scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Patay, E.

    2008-07-15

    The deployment of a market for hydrogen energy is a new problem, considered by governments, industrialists and scientists to meet global targets of greenhouse gases emissions reduction and to ensure security in energy supply. In this context, the optimization problem of scheduling the deployment until 2050 of the hydrogen supply chain for fuel market throughout a country has been the object of our study. We get support of Air Liquide Company, his experience and experts in production and distribution of industrial hydrogen, to build an approach to the problem meeting the requirements of an industrial context. After defining and characterizing the optimization problem through a systemic analysis of the distribution infrastructure, we proposed a method suited to its resolution. Monte Carlo simulations enabled us to develop cost functions. Then we developed a heuristic algorithm for approximate optimization of these cost functions. Our approach has necessitated the definition of simulation rules, a design of experiment and a regression method, as well as a heuristic algorithm adapted to the structure of the problem. The specification, development and use of software tools have helped to validate the chosen methodology for the optimization of the uncertain problem of our study. The scenario of evolution has created a reference to validate the model and provide some analysis for early studies of deployment. (author)

  3. Behaviour analysis of the fuel injected in the intake manifold of port-injected spark ignition engines: modeling and experimental validation; Analyse du comportement du carburant injecte dans les conduits d`admission des moteurs a allumage commande a injection multipoint: modelisation et validation experimentale

    Energy Technology Data Exchange (ETDEWEB)

    Sches, C.

    1999-01-27

    In order to limit pollutant emissions resulting from transient engine operation, the mastering of mixture formation is essential. In this context, an interactive work was undertaken between a modeling job and an experimental study, to get better understanding of the mechanisms of fuel dynamic behavior in the intake manifold of port-injected spark-ignition engines. The experimental study, elaborated thanks to experimental designs, showed out two essential factors: injection timing and coolant liquid temperature, which act on the fuel dynamic behavior through a second order filter. Then, a phenomenological modeling was established and validated, to analyze the various phenomena influencing mixture formation and to calculate the air/fuel ratio evolutions during transient operation. This program uses the results of a 3D model describing the fuel spray transportation, evaporation and impact on the port walls. The calculation does not need any boundary conditions and the running times are vary satisfactory. We showed that a correct description of the liquid fuel film was necessary to get good prediction of the mixture fuel/air ratio. The spray modeling, which is necessary, can however be kept simple. Future work may develop either in the engine control filed (injection strategies development, optimization of the injection system configuration, ...), or in the theoretical field (better modeling of fuel film displacement or of secondary atomization of the fuel on the intake valve). (author) 79 refs.

  4. Properties of point defects either native or induced by irradiation in the 3C and 6H polytypes of silicon carbide determined by positron annihilation and EPR; Proprietes des defauts ponctuels natifs et induits par irradiation dans les polytypes 3C et 6H du carbure de silicium determinees par annihilation de positons et RPE

    Energy Technology Data Exchange (ETDEWEB)

    Kerbiriou, X

    2006-02-15

    Potential applications of silicon carbide (SiC) in micro-electronics have justified many studies on point defects, which play an important role in the electrical compensation. Moreover, this material has many assets to take part in the fissile materials confining in the gas cooled reactors of the future (4. generation). In this thesis, we have used Electronic Paramagnetic Resonance and Positron Annihilation Spectroscopy to study the properties of point defects (nature, size, charge state, migration and agglomeration during annealing), either native or induced by irradiation with various particles (H{sup +}, e{sup -}, carbon ions), in the 3C and 6H polytypes of SiC. The positron annihilation study of native defects in 6H-SiC has shown the presence of a strong concentration of non-vacancy traps of acceptor type, which are not present in the 3C-SiC crystals. The nature of the defects detected after irradiation with low energy electrons (190 keV) depends on the polytype. Indeed, while silicon Frenkel pairs and carbon mono-vacancies are detected in the 6H crystals, only carbon mono-vacancies are detected in the 3C crystals. We propose that these differences concerning the populations of detected point defects result from different values of the silicon displacement threshold energy for the two polytypes (approximately 20 eV for 6H and 25 V for 3C). In addition, the irradiations with 12 MeV protons and 132 MeV carbon ions have created silicon mono-vacancies as well as VSi-VC di-vacancies. Neither the particle (protons or ions carbon), nor the polytype (3C or 6H) influence the nature of the generated defects. Finally the study of the annealing of 6H-SiC monocrystals irradiated with 12 MeV protons have revealed several successive processes. The most original result is the agglomeration of the silicon mono-vacancies with the VSi-VC di-vacancies which leads to the formation of VSi-VC-VSi tri-vacancies. (author)

  5. Économie d'un procédé d'hydrolyse enzymatique et fermentation de la paille de blé pour la production d'alcool carburant Economics of a Process for Producing Alcohol Fuels by Enzymatic Hydrolysis and Fermentation of Wheat Straw

    Directory of Open Access Journals (Sweden)

    Arlie J. P.

    2006-11-01

    Full Text Available Après définition des grandes lignes d'un procédé de base d'hydrolyse-fermentation de la paille de blé, l'analyse de sensibilité montre que le rendement de l'hydrolyse a une grande importance sur les bilans énergétique et économique. Des rendements de l'ordre de 85 % permettent d'obtenir des valeurs d'investissement par tonne de pétrole économisée tout à fait comparables à celles obtenues par d'autres techniques de valorisation de la biomasse en alcool, telle la synthèse du méthanol obtenu après gazéification du bois à l'oxygène. The basic features of a process for production from cereal straw of an acetone-butanol mixture for use as a gasoline substitute are described. They include pretreatment and enzymatic hydrolysis of the substrate followed by fermentation of the sugars produced. A cost evaluation based on the performances of a reference process is presented. Then, an analysis of the sensitivity of the cost price of the process to the variation of the important parameters such as production capacity, enzyme productivity, hydrolysis yield is carried out. The energy balance of the process is presented.

  6. Study of irradiation effects in the silicon carbide cubic polytype by photoluminescence and electron spin resonance spectroscopies; Etude des effets d'irradiation dans le polytype cubique du carbure de silicium par les techniques spectroscopiques de photoluminescence et de resonance paramagnetique electronique

    Energy Technology Data Exchange (ETDEWEB)

    Lefevre, J

    2008-01-15

    This experimental work has consisted in the study of point defects induced by an electronic irradiation in the cubic crystallographic structure of silicon carbide with low temperature photoluminescence and electron spin resonance spectroscopies. The first one of these measurement tools has allowed to estimate the displacement threshold energy in the silicon sub-lattice and then to analyze the thermal stability of the irradiation defects in the low temperature range: (10-300 K) and then in the high temperature range: (300-1400 K). Besides, on the base of a recent theoretical model, this thesis has confirmed the proposition of the isolated silicon antisite for the D1 center whose running beyond the nominal running temperature of fission nuclear reactors (generation IV), for which SiC is in part intended, seems to be particularly problematic. Measurements carried out by ESR under lighting have at last allowed to detect a new defect in its metastable spin state S=1, possibly associated to a silicon interstitial configuration. (O.M.)

  7. Modification in the Microstructure of Mod. 9Cr-1Mo Ferritic Martensitic Steel Exposed to Sodium

    Science.gov (United States)

    Prasanthi, T. N.; Sudha, Cheruvathur; Paul, V. Thomas; Bharasi, N. Sivai; Saroja, S.; Vijayalakshmi, M.

    2014-09-01

    Mod. 9Cr-1Mo is used as the structural material in the steam generator circuit of liquid metal-cooled fast breeder reactors. Microstructural modifications on the surface of this steel are investigated after exposing to flowing sodium at a temperature of 798 K (525 °C) for 16000 hours. Sodium exposure results in the carburization of the ferritic steel up to a depth of ~218 µm from the surface. Electron microprobe analysis revealed the existence of two separate zones with appreciable difference in microchemistry within the carburized layer. Differences in the type, morphology, volume fraction, and microchemistry of the carbides present in the two zones are investigated using analytical transmission electron microscopy. Formation of separate zones within the carburized layer is understood as a combined effect of leaching, diffusion of the alloying elements, and thermal aging. Chromium concentration on the surface in the α-phase suggested possible degradation in the corrosion resistance of the steel. Further, concentration-dependent diffusivities for carbon are determined in the base material and carburized zones using Hall's and den Broeder's methods, respectively. These are given as inputs for simulating the concentration profiles for carbon using numerical computation technique based on finite difference method. Predicted thickness of the carburized zone agrees reasonably well with that of experiment.

  8. Thermodynamic study and methanothermal temperature-programmed reaction synthesis of molybdenum carbide

    Science.gov (United States)

    Roohi, Parham; Alizadeh, Reza; Fatehifar, Esmaeil

    2016-03-01

    Nanostructured molybdenum carbide (Mo2C) was successfully prepared from molybdenum trioxide (MoO3) using methanothermal temperature-programmed reaction. Thermodynamic analysis indicated that in presence of methane, the formation of Mo2C from MoO3 occurs through the path of MoO3 → MoO2 → Mo2C. The carburized MoO3 was characterized using X-ray diffraction (XRD), CHNS/O analysis, Brunauer-Emmett-Teller (BET) analysis, and field-emission scanning electron microscopy (FESEM). At final carburization temperatures of 700 and 800°C and at methane contents ranging from 5vol% to 20vol%, Mo2C was the only solid product observed in the XRD patterns. The results indicated that the effect of methane content on the formation of the carbide phase is substantial compared with the effect of carburization time. Elemental analysis showed that at a final temperature of 700°C, the carbon content of carburized MoO3 is very close to the theoretical carbon mass percentage in Mo2C. At higher carburization temperatures, excess carbon was deposited onto the surface of Mo2C. High-surface-area Mo2C was obtained at extremely low heating rates; this high-surface-area material is a potential electrocatalyst.

  9. 碳化镍钼催化剂的制备及其甲烷干气重整活性%Preparation of a Nickel Molybdenum Carbide Catalyst and Its Activity in the Dry Reforming of Methane

    Institute of Scientific and Technical Information of China (English)

    Taro HIROSE; Yasushi OZAWA; Masatoshi NAGAI

    2011-01-01

    Nickel molybdenum carbide catalysts were prepared and their activities in the CO2 reforming of methane at a low CO2/CH4 reactant ratio were investigated using a microreactor at atmospheric pressure and at 973 K The effect of the catalyst preparation method and the Ni/Mo ratio on the increase in catalyst life and the promotion of catalytic activity were investigated using N2 adsorption, X-ray diffraction,temperature-programmed carburization, temperature-programmed reaction, and a reforming reaction. The 25Ni75Mo catalyst that was carburized at 813 K exhibited the highest hydrogen fonnation ability and gave the least carbon deposition. The incomplete carburization of the Mo oxide species in the catalyst that was carburized at a lower temperature gradually gave a more active carburized species. The NiMoOxCy in the catalyst was more active in hydrogen formation during the dry reforming of methane while β-Mo2C and η-Mo3C2 were less active.

  10. Efficiency of protective coatings on high creep resistant cast steel

    Directory of Open Access Journals (Sweden)

    J. Kubicki

    2009-04-01

    Full Text Available This paper presents results of research of multilayer aluminium–silicon coatings. Aluminium–silicon coatings were created on high–temperature creep resist cast iron using slurry method in air atmosphere. These coatings protect equipment against hot corrosionin carburizing atmosphere at thermal shocks conditions.Various technological parameters of coatings manufacturing were applied. Main technological parameters were: temperature and time ofannealing and Al-Si ratio in the active mixture. The structure of obtained coatings is three-zonal. Phase composition of two external zones ensures protection against carburizing, but these zones are not resistant to cracking. The cracks form as a result of thermal shocks. The internal zone of the coatings situated next to substrate compensates for differences of thermal expansion of the coating and the substrate. The cracks are stopped in the internal zone and do not propagate into the substrate material. Protective efficiency of the coatings at carburizing conditions with thermal shocks was determined. Structure of the coatings before and after carburizing and thermal shocks is described in present paper. Thickness, chemical composition (EDS and phase composition (XRD of the coatings are determined. Correlation between the coatings structure and depth of carburized layer was determined.

  11. Characterization of complex (B + C) diffusion layers formed on chromium and nickel-based low-carbon steel

    Energy Technology Data Exchange (ETDEWEB)

    Pertek, A.; Kulka, M

    2002-12-30

    Combined surface hardening with boron and carbon was used for low-carbon chromium and nickel-based steels. The microstructure, boron contents, carbon profiles and chosen properties of borided layers produced on the carburized steels have been examined. These complex (B+C) layers are termed borburized layers. The microhardness profiles and wear resistance of these layers have been studied. In the microstructure of the borocarburized layer two zones have been observed: iron borides (FeB+Fe{sub 2}B) and a carburized layer. The depth (70-125 {mu}m) and microhardness (1500-1800 HV) of iron borides zone have been found. The carbon content (1.2-1.94 wt.%) and microhardness (700-950 HV) beneath iron borides zone have been determined. The microhardness gradient in borocarburized layer has been reduced in comparison with the only borided layer. An increase of distance from the surface is accompanied by a decrease of carbon content and microhardness in the carburized zone. The carbon and microhardness profiles of borided, carburized and borocarburized layers have been presented. A positive influence of complex layers (B+C) on the wear resistance was determined. The wear resistance of the borocarburized layer was determined to be greater in comparison with that for only borided or only carburized layers.

  12. Ultrasonic cavitation erosion of a duplex treated 16MnCr5 steel

    Energy Technology Data Exchange (ETDEWEB)

    Mitelea, Ion; Ghera, Christian; Craciunescu, Corneliu M. [Timisoara Univ. (Romania). Dept. of Materials and Manufacturing Engineering; Bordeasu, Ilare [Timisoara Univ. (Romania). Dept. of Mechanical Machines, Equipments and Transportation

    2015-04-15

    Ultrasonic cavitation experiments using a piezoceramic-based apparatus, according to ASTM G32-2010, were performed on heat and thermochemically treated Cr - Mn low alloyed steel samples. The microstructure in annealed, carburized and tempered states as well as following a duplex treatment (carburized, surface induction hardening and tempering) was analyzed before and after the cavitation erosion tests. The results show the advantage of the duplex treatment, with a significant increase of up to 20 times of the cavitation erosion resistance compared to the annealed state and reveal that the main mechanism for surface deterioration is micro-cracking. The observations are important for the improvement of the behaviour for parts used in hydraulic equipment, for which the volume hardening following the carburization can be replaced by cost-efficient surface induction hardening treatments.

  13. Formation of high-carbon abrasion-resistant surface layers when high-energy heating by high-frequency currents

    Science.gov (United States)

    Plotnikova, N. V.; Skeeba, V. Yu; Martyushev, N. V.; Miller, R. A.; Rubtsova, N. S.

    2016-11-01

    The paper shows the possibility of carburization of low-carbon steel surface layers using high-frequency currents. The mathematical modeling of carburization using high-energy heating by high-frequency currents (HEH HFC) has been carried out, the temperature fields formed during the given processing have been calculated, as well as the structural changes in the surface layers have been simulated. The features of the structure formation in the surface layers of low-carbon steel after carburizing via HEH HFC have been determined by optical and scanning microscopy, which is confirmed by the computational models. The rational mode of fusion via HEH HFC has also been determined (power density of the source qs = (1.5 ... 4.0) • 108 W m-2, (the relative travel speed of parts Vp = 5 ... 100 mm / sec), with forming the compressive retained stresses in the surface layer (σRS ≈ -300 ... -400 MPa).

  14. A Novel Method for Direct Synthesis of WC-Co Nanocomposite Powder

    Science.gov (United States)

    Zhu, M.; Bao, X. Y.; Yang, X. P.; Gu, N. S.; Wang, H.; Zeng, M. Q.; Dai, L. Y.

    2011-09-01

    In this study, a novel method, termed dielectric-barrier-discharge-plasma (DBDP) assisted ball milling and low-temperature carburization, was used to synthesize WC-Co nanocomposite powder. X-ray diffraction, scanning/transmission electron microscopy, and differential scanning calorimetry were used to characterize the microstructure of powders. Starting from W, Co, and graphite powder mixtures, the DBDP-milled W-C-10Co powder exhibited a flakelike morphology with very fine lamellar structure. The WC-Co composite powder was synthesized at 1273 K (1000 °C), which is much lower than the requisite temperature for the conventional carburizing method. The obtained WC-Co composite powder had a nanocomposite microstructure in which fine WC particles were bounded by homogenously distributed Co phase, and the WC crystals had a slablike morphology with a planar size of about 200 nm and carburization temperature and the nanocomposite structure of WC-Co powder.

  15. Determination of Concentration Dependent Diffusion Coefficients of Carbon in Expanded Austenite

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo; Christiansen, Thomas; Somers, Marcel A. J.

    2008-01-01

    Abstract. In the present paper various experimental procedures to experimentally determine the concentration dependent diffusion coefficient of carbon in expanded austenite are evaluated. To this end thermogravimetric carburization was simulated for various experimental conditions and the evaluated...... composition dependent diffusivity of carbon derived from the simulated experiments was compared with the input data. The most promising procedure for an accurate determination is shown to be stepwise gaseous carburizing of thin foils in a gaseous atmosphere; the finer the stepsize, the more accurate...... the approximation of the diffusivity. Thermogravimetry was applied to continuously monitor the weight change of thin foils of AISI 316 during carburizing in CO-H2 gas mixtures for one of the simulated experimental procedures....

  16. Tribocorrosion of low carbon steel C15E IN 5% NaCl and 5% NaCl + SiO2

    Directory of Open Access Journals (Sweden)

    S. Aračić

    2010-04-01

    Full Text Available The article represents testing results of corrosion and erosion-corrosion wear. Specimens have been made from low carbon steel C15E in four different states: delivery state and heat-treated (carburizing, boronising and carburizing + boronising. The results are shown as wear of materials (losing of surface mass in mg/(cm2 • d. Surface hardness method HV1 and micro hardness per section of specimen HV0,2 method have been used during the analyses. A comparison of testing results of wear in four different states was made. The best performances have shown samples which have been treated with duplex procedure (carburizing + boronising as was predicted.

  17. Synthesis of nanosized tungsten carbide from phenol formaldehyde resin coated precursors

    Institute of Scientific and Technical Information of China (English)

    LUO Ji; GUO Zhimeng; GAO Yuxi; LIN Tao

    2008-01-01

    Nanosized tungsten carbide was synthesized from phenol formaldehyde resin (PF) coated tungsten precursors.The process has three steps in which nanosized tungsten particles were first coated with PF,then the precursors were carburized at 950℃,and finally the carburized powders were treated in flowing wet hydrogen atmosphere at 940℃ to remove the uncombined carbon.The obtained powders were characterizedusing X-ray diffraction analysis (XRD),field-emission scanning electron microscopy (FESEM),small angle X-ray scattering (SAXS),andcombustion-gas-volume method.The results indicated that single-phase WC could be synthesized using excessive PF as carburizer at a muchlower temperature compared with using mixed carbon black.After wet hydrogen treating,the mean size of the obtained WC particles was 94.5nm and the total carbon content was 6.18 wt.%.

  18. Automated methanol dosage using liquid flow controllers; Automatisierte Methanolregelung mit Liquid Flow Controllern

    Energy Technology Data Exchange (ETDEWEB)

    Sattler, Thomas [Buerkert Fluid Control Systems, Ingelfingen (Germany)

    2010-12-15

    Transmission gearwheels are frequently exposed to extreme loads. Generally, in order to counteract premature wear, gearwheels made from steel are surface-hardened. This is carried out primarily by gas carburizing and subsequent quenching (case hardening). These processes of gas carburizing increase the carbon content in the boundary area of the workpiece and change the boundary structure of the steel. In the foundation Institut fuer Werkstofftechnik (IWT) (Institute for Materials Engineering) in Bremen, they are engaged intensively with the various processes of heat treatment for the hardening of steel. As an alternative to gas carburizing using endogas, the Nitrogen-Methanol Process, in which liquid methanol is directly introduced into the furnace, plays an important role and is gaining in importance. At the IWT, Liquid Flow Controllers (LFC) provide regulated and completely documented processes. (orig.)

  19. Effects of Deep Cryogenic Treatment on Wear Mechanisms and Microthermal Expansion for the Material of Drive Elements

    Directory of Open Access Journals (Sweden)

    Yuh-Ping Chang

    2013-01-01

    Full Text Available By the composite heat treatments, the strength and the surface hardness of the materials of drive elements can be improved. Moreover, the high accurate and capable machines can be obtained. For the numerous composite heat treatments, the deep cryogenic treatment has been used widely for the purpose of low thermal expansion in the industry. Therefore, this paper is further to investigate the low friction, wear resistance, and low thermal expansion for the carburizing steels of drive elements with deep cryogenic treatment. According to the experimental results, martensitic transformation occurred after the deep cryogenic treatment. The effects of deep cryogenic treatment on wear mechanisms are significant. The shape of wear particles changes from slip tongue to smooth stratification. Moreover, the surface magnetization is smaller for the case of Carburizing-Deep cryogenic treatment. Hence, the wear mechanism becomes simple. Besides, the thermal expansion is significantly smaller for the case of Carburizing-Deep cryogenic treatment.

  20. Natural gas use in treatment of steel surfaces; Utilizacao de gas natural em tratamento de superficies de aco

    Energy Technology Data Exchange (ETDEWEB)

    Ferraz, Andre Dias; Machado, Antonio Rogerio; Rocha, Ivan; Azevedo, Jorge; Oshiro, Hugo K.; Konishi, Ricardo; Lehmkuhl, Willian [Companhia de Gas de Santa Catarina (SCGAS), Florianopolis, SC (Brazil); Piazza, Walter [PETROBRAS, Rio de Janeiro, RJ (Brazil)

    2011-12-21

    The surface treatments of metals, such as carburizing, rely on processing under high temperature in carbon rich atmospheres. The atmosphere is industrially generated using the partial oxidation of a carbon rich fuel, such as propane, butane or methanol. This article reports a study of the production of a carburizing atmosphere for surface treatment of steel from the partial oxidation of natural gas in a catalytic reactor. The reactor studied was a production size reactor with 300 mm of diameter and 1500 mm of length, packed with alumina supported nickel catalyst. The quality of the carburizing gas was evaluated from its carbon potential of the carburizing gas that was calculated from the concentrations of carbon monoxide (CO), carbon dioxide (CO{sub 2}), oxygen (O{sub 2}) and methane (CH{sub 4}) measured at the reactor's exit. The results indicate that CO concentration is very close to equilibrium, while CO{sub 2} is higher and CH{sub 4} is lower. Examining the reactor, the conclusion was that there was an axial temperature gradient, resulting in lower residence time under the required processing temperature. This resulted in smaller decomposition of CH{sub 4} and smaller production of CO{sub 2}. An equilibrium calculation of carbon potential, expressed as weight percent of carbon in iron, was developed to predict the possible optimizations of mixture composition and reactor temperature for a given required carbon potential. Conclusion: it is possible to generate a carburizing atmosphere under well controlled and repeatable conditions for the carbon potentials required for surface carburizing of steels in industrial processing using natural gas and air mixtures. (author)

  1. Technology of Iron Carbide Synthesis

    Institute of Scientific and Technical Information of China (English)

    M.Bahgat

    2006-01-01

    Iron carbides are very promising metallurgical products and can be used for steelmaking process, where it plays as an alternative raw material with significant economic advantages. Also it has many other applications,e.g. catalysts, magnets, sensors. The present review investigates the different properties and uses of the iron carbides. The commercial production and the different varieties for the iron carbides synthesis (gaseous carburization, mechanochemical synthesis, laser pyrolysis, plasma pyrolysis, chemical vapor deposition and ion implantation) were reviewed. Also the effect of different factors on the carburization process like gas composition, raw material, temperature, reaction time, catalyst presence and sulfur addition was indicated.

  2. Flexible Furnace Concepts for Vacuum Heat Treatment Combined with High-pressure Gas Quenching

    Institute of Scientific and Technical Information of China (English)

    Karl Ritter; Stefan Wiebach

    2004-01-01

    IN the past five years the process combination of vacuum hardening, respectively vacuum carburizing with high-pressure gas quenching was successfully introduced to the market, especially in the manufacture of gears. In the meantime furnace concepts for various applications are available to the industry. In the following report three plant varieties are introduced, which differ in process flexibility and throughput. This report also explains criteria for the selection of a furnace in view of the existing application requirements. Besides this a short introduction is given into the vacuum carburizing process and the high-pressure gas quenching technology.

  3. 碳氮共渗

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    [篇名 ] A study on friction and wear behaviour of carburized, carbonitrided and borided AISI 1020 and 5115 steels, [篇名 ] Alloy Carburization at Temperatures of 1,200 - 2,100 F(650-1,150 ℃), [篇名] Amorphous silicon carbonitride fibers drawn from alkoxide modified ceraser, [ 篇名 ] Bearings with incrcased reliability, [篇名 ] Bright outlook for hard coatings, [ 篇名 ] Carbonitridc coating by low-temperature diffusion process, [ 篇名 ] Carbonitridc nanomaterials, thin films, and solids.

  4. Thermal residual stress analysis of diamond coating on graded cemented carbides

    Institute of Scientific and Technical Information of China (English)

    HUANG Zi-qian; HE Yue-hui; CAI Hai-tao; WU Cong-hai; XIAO Yi-feng; HUANG Bai-yun

    2008-01-01

    Finite element model was developed to analyze thermal residual stress distribution of diamond coating on graded and homogeneous substrates. Graded cemented carbides were formed by carburizing pretreatment to reduce the cobalt content in the surface layer and improve adhesion of diamond coating. The numerical calculation results show that the surface compressive stress of diamond coating is 950 MPa for graded substrate and 1 250 MPa for homogenous substrate, the thermal residual stress decreases by around 24% due to diamond coating. Carburizing pretreatment is good for diamond nucleation rate, and can increase the interface strength between diamond coating and substrate.

  5. Use of vacuum carbonitriding for raising the seizure resistance of gears from steel VKS-10

    Science.gov (United States)

    Lashnev, M. M.; Smirnov, A. E.; Semenov, M. Yu.

    2013-05-01

    Saturation of heat-resistant steel VKS-10 with carbon and nitrogen in a low-pressure atmosphere is studied. The possibility of increasing the fineness of the carbonitride phase and the content of retained austenite in vacuum carbonitriding is shown as compared to vacuum carburizing. Subsequent aging results in segregation of a still finer excess phase. The factors controlling vacuum carbonitriding are determined. Comparative estimation of the seizure resistance of carbonitrided layers of steel VKS-10 and carburized layers obtained on traditional heat-resistant steels is performed.

  6. Effect of Nano Oil Additive Proportions on Friction and Wear Performance of Automotive Materials

    Directory of Open Access Journals (Sweden)

    A. Vadiraj

    2012-03-01

    Full Text Available The effect of nano boric acid and nano copper based engine and transmission oil additives in different volume ratios (1:10, 2:10, and 3:10 on friction and wear performance of cast iron and case carburized gear steel has been investigated. The results show that coefficient of friction increases with increase in volume ratio of engine oil additives and decreases with increasing in volume ratio of transmission oil additives. Cast iron substrate shows higher wear damage than case carburized gear steel. Nano copper additive with crystalline atomic structure shows more severe three body wear compared to boric acid with layered lattice structure.

  7. Microwave heat treating of manufactured components

    Science.gov (United States)

    Ripley, Edward B.

    2007-01-09

    An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases. The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

  8. Modelling of composition and stress profiles in low temperature surface engineered stainless steel

    DEFF Research Database (Denmark)

    Jespersen, Freja Nygaard; Hattel, Jesper Henri; Somers, Marcel A. J.

    2015-01-01

    Thermochemical surface engineering by nitriding/carburizing of stainless steel causes a surface zone of expanded austenite, which improves the wear resistance of the stainless steel while preserving the stainless behavior. As a consequence of the thermochemical surface engineering, huge residual...

  9. The formation of filamentous carbon on iron and nickel catalysts : II. Mechanism

    NARCIS (Netherlands)

    Kock, A.J.H.M.; Bokx, P.K. de; Boellaard, E.; Klop, W.; Geus, John W.

    1985-01-01

    The mechanism of filamentous carbon growth on iron and nickel catalysts has been studied using a combination of magnetic techniques and temperature-programmed hydrogenation. CO and CH4 were used as carburizing agents. It is concluded that high carbide contents are a prerequisite for the nucleation o

  10. Simulation of Case Depth of Cementation Steels According to Fick's Laws%Simulation of Case Depth of Cementation Steels According to Fick's Laws

    Institute of Scientific and Technical Information of China (English)

    S R Elmi Hosseini

    2012-01-01

    The carburizing process is the enrichment of the depth of low carbon steels with carbon. It leads to samples with a combination of high surface hardness and high core toughness and to an impact strength that is required for many engineering parts. The material studied is a low carbon steel. The carbon content is little in this type of steel (wc = 0.2 ~). The calculation of case depth is very important for cementation steels that are hardened in the carburi- zing process. The effective case depth is defined as the perpendicular distance from the surface to a place at which the hardness is HV 550. Nowadays, a great number of studies have been carried out on the simulation of effective case depth, but no studies have been conducted to determine the numerical relation between the total case depth on one hand and the carburizing time and the effective case depth on the other hand. The steel specimens were subjected to graphite powder. Then, they were heat treated at 925 ~C for about 3, 5, 8 and 12 h, respectively. Then, these parts were quenched in oil. To determine the effective case depth, the micr0hardness test was performed on the cross-section of specimens. Plotting the case depth vs carburizing time, the required conditions for obtaining the specified case depth were determined. Also, the comparison between the case depths in numerical solution and the actual position in pack carburizing was performed.

  11. Lattice expansion of carbon-stabilized expanded austenite

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The lattice parameter of expanded austenite was determined as a function of the content of interstitially dissolved carbon in homogeneous, carburized thin stainless steel foils. For the first time this expansion of the face-centered cubic lattice is determined on unstrained austenite. It is found...

  12. Effects of Nitride on the Tribological Properties of the Low Carbon Alloy Steel

    Directory of Open Access Journals (Sweden)

    Yuh-Ping Chang

    2013-01-01

    Full Text Available The technology of composite heat treatment is used popularly for low friction and wear resistance of drive elements. A large number of papers about the heat treatment technology had been proposed. Especially, the nitride treatment has been used widely for the purpose of wear resistance and low friction in the industry. Therefore, the self-developed vertical ball/disk friction tester with the measurement system was used to study the effects of nitride on the tribological properties of the low carbon alloy steel—SCM415— in this study. The experiments were conducted under dry and severe wear conditions. The variations of friction coefficient and surface magnetization were simultaneously recorded during dynamic friction process. After each test, the microstructures of the wear particles were observed and analyzed under a SEM, and the depth of wear track is measured by means of a surface tester. According to the experimental results, the wear resistance of the specimens with carburizing-nitride is significantly larger than the case of nitride-carburizing. Moreover, the surface magnetization was especially larger for the case of nitride-carburizing. As a result, the wear particles always stay in the interfaces and the wear mechanism becomes complex. Therefore, it is necessary to put nitride after carburizing for the composite heat treatments.

  13. WC@meso-Pt core-shell nanostructures for fuel cells.

    Science.gov (United States)

    Chen, Zhao-Yang; Ma, Chun-An; Chu, You-Qun; Jin, Jia-Mei; Lin, Xiao; Hardacre, Christopher; Lin, Wen-Feng

    2013-12-25

    We developed a facile method to synthesize core-shell WC@meso-Pt nanocatalysts by carburizing ammonium tungstate and copper nitrate via gas-solid reactions, followed by a Pt replacement reaction. The mesoporous nanocomposite displays higher activity and stability towards methanol electrooxidation than commercial Pt/C catalysts.

  14. Apparatus with moderating material for microwave heat treatment of manufactured components

    Science.gov (United States)

    Ripley, Edward B.

    2011-05-10

    An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

  15. Computation-Based Analysis of the Methods of Hardening of Gears from Heat-Resistant Steels

    Science.gov (United States)

    Semenov, M. Yu.; Gavrilin, I. N.; Ryzhova, M. Yu.

    2014-05-01

    A mathematical model is developed for estimating the contact fatigue of gears subjected to various kinds of thermochemical treatment. The model includes design of the contact stress state and of the loading capacity of the diffusion layer. The ranges of application of vacuum carburizing, vacuum carbonitriding, and ion nitriding for hardening gears with various geometrical parameters are determined.

  16. Spark alloying of VK8 and T15K6 hard alloys

    Science.gov (United States)

    Kuptsov, S. G.; Fominykh, M. V.; Mukhinov, D. V.; Magomedova, R. S.; Nikonenko, E. A.; Pleshchev, V. P.

    2015-08-01

    A method is developed to restore the service properties of VK hard alloy plates using preliminary carburizing followed by spark alloying with a VT1-0 alloy. The phase composition is studied as a function of the spark treatment time.

  17. Application of standard end-quench test to structural steel with elevated carbon content at low hardenability

    Science.gov (United States)

    Gliner, R. E.; Vybornov, V. V.

    2013-03-01

    Special features of the test of plain steel with elevated carbon content for hardenability, which is used in the production of gears instead carburizing alloy steel, are considered. It is shown that it is possible and effective to use computer simulation of the hardenability detectable by testing of this class of steel by the method of end quenching with allowance for the chemical composition.

  18. 淬火

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Phase Formation and Microstructure of Titanium Oxides and Composites Produced by Thermal Plasma Oxidation of Titanium Carbide.Strocture and properties of the hardened carburized layer of low-carbon chromium-nickel steel after quenching in diffcrent media-Part Ⅰ.Experimental setup for thermal fatigue testing of steels for the casting tools.

  19. 铁氧体

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A model of spin wave resonance in grain-surface-layers for effective linewidth and channels of energy transfer on polycrystals,A NEW METHOD OF DETERMINATION OF OXYGEN DIFFUSIVITIES IN POLYCRYSTALLINE FERRITE AND ITS VERIFICATION BY A NUCLEARMICRO ANALYSIS METHOD,A new simulation tool for the calculation of carboncon centration-distance curves - prediction and analysis of carburization and decarburization profiles

  20. Expanded austenite; crystallography and residual stress

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2009-01-01

    The identity of expanded austenite as developing during low temperature nitriding and/or carburizing of austenitic stainless steel has been under debate since the very first observation of this phase. In the present article recent results obtained with i) homogeneous samples of various uniform...

  1. Apparatus for microwave heat treatment of manufactured components

    Science.gov (United States)

    Babcock & Wilcox Technical Services Y-12, LLC

    2008-04-15

    An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases. The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

  2. Research of the Tribological Properties of the Surface on 16Mn Steel by Plasma Nitriding and S-N-C Plasmas Composite Treatment

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-chun; ChEN Rui

    2004-01-01

    Sulfide layer with certain thickness was made on the nitrided surface of 16Mn steel by means of plasma S-C-N composite treatment. Under half lubricated condition, friction coefficient and wear loss of LY12 aluminum alloy were measured in sliding against samples of 16Mn treated by cubrizing and sulphiding respectively; In order to avoid the transfer of aluminum to the steel that lead to the inaccurate measurement of wear loss of carburized samples, Gr15 steel was adopted as counterpart face to measure the wear loss of them. SEM and EDAX were used for the morphological and chemical characterization of the wear surface and longitudinal cross-sections beneath sliding surface of LY12 aluminum alloy cirque and the wear tacks of the carburized samples and sulphided samples. Results show: The surface roughness,wear rate, average friction coefficient and magnitude of friction fluctuations of LY 12 aluminum alloy cirque sliding against sulphided sample were all lower than sliding against carburized sample; Compared with carburized layer, sulfide layer of 16Mn steel can not only efficiently prevent the occurrence of adhesion when sliding against LY12 aluminum alloy, but also greatly lower the wear loss when sliding against Grl 5 steel.

  3. Changes Found on Run-In and Scuffed Surfaces of Steel Chrome Plate, and Cast Iron

    Science.gov (United States)

    Good, J. N.; Godfrey, Douglas

    1947-01-01

    A study was made of run-in and scuffed steel, chrome-plate, and cast-iron surfaces. X-ray and electron diffraction techniques, micro-hardness determinations, and microscopy were used. Surface changes varied and were found to include three classes: chemical reaction, hardening, and crystallite-size alteration. The principal chemical reactions were oxidation and carburization.

  4. The ternary Fe-C-N system: Homogeneous distributions of nitrogen and carbon

    DEFF Research Database (Denmark)

    Brink, Bastian; Ståhl, Kenny; Christiansen, Thomas Lundin;

    2017-01-01

    of the nitriding and carburizing potentials, tailored nitrogen and carbon contents can be achieved, which allows assessment of a phase stability diagram for the Fe-N-C system, for which available experimental data is limited. Thermal decomposition sequences were established for the various iron carbides and (carbo...

  5. 斜齿圆柱齿轮

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A technology for cold forging of helical gear with crowning using elastic deformation of die;Development of new driving system sunroof; Effect of the gear-shaper cutter grinding on 8 surface on its geometry and profile errors; Mathematical model and undercutting analysis of modified helical gears with smaller number of teeth; Predicting the heat-treat response of a carburized helical gear

  6. Stress and Composition of Carbon Stabilized Expanded Austenite on Stainless Steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Somers, Marcel A. J.

    2009-01-01

    Low-temperature gaseous carburizing of stainless steel is associated with a colossal supersaturation of the fcc lattice with carbon, without the development of carbides. This article addresses the simultaneous determination of stress and composition profiles in layers of carbon xpanded austenite...

  7. Methods for microwave heat treatment of manufactured components

    Science.gov (United States)

    Ripley, Edward B.

    2010-08-03

    An apparatus for heat treating manufactured components using microwave energy and microwave susceptor material. Heat treating medium such as eutectic salts may be employed. A fluidized bed introduces process gases which may include carburizing or nitriding gases. The process may be operated in a batch mode or continuous process mode. A microwave heating probe may be used to restart a frozen eutectic salt bath.

  8. Extended X-Ray Absorption Fine Structure Investigation of Carbon Stabilized Expanded Austenite and Carbides in Stainless Steel AISI 316

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas; Ståhl, Kenny;

    2011-01-01

    Low temperature carburized AISI 316 stainless steel - carbon expanded austenite - was investigated with EXAFS and synchrotron diffraction together with synthesized carbides of the type M3C2, M7C3 and M23C6. It was found that the chemical environment of carbon expanded austenite is not associated ...

  9. Verbindungsschichtbildung beim Nitrieren und Nitrocarburieren

    DEFF Research Database (Denmark)

    Somers, Marcel A. J.

    2011-01-01

    diffusion and desorption or the competition with a carburizing reaction. During compound layer growth the nitriding kinetics are determined by a combination of solid state diffusion of interstitial elements and the kinetics of the surface reactions. Moreover, phase transformations within the compound layer...

  10. On the Carbon Solubility in Expanded Austenite and Formation of Hägg Carbide in AISI 316 Stainless Steel

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lundin; Ståhl, Kenny; Brink, Bastian;

    2016-01-01

    –420 °C and 465–470 °C, respectively. Hägg carbide (x-M5C2)develops when the carbon content in the expanded austenite exceeds the metastable solubility limit; the transformation of carbon expanded austenite into Hägg carbide occurs irrespective of carburizing temperature in the investigated temperature...

  11. TPR and TPD studies of effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts

    Indian Academy of Sciences (India)

    Olusola O James; Biswajit Chowdhury; Sudip Maity

    2013-05-01

    Temperature-programmed reduction (TPR) and temperature-programmed desorption (TPD) were used to study the effects of Cu and Ca promotion on Fe-Zn-based Fischer-Tropsch catalysts. The reduction temperature for Fe2O3 → Fe3O4 was unaffected by Ca addition but decreased when promoted with Cu. Fe-Zn promoted with Cu and Ca showed even much lower reduction temperature for Fe2O3→Fe3O4. Ca promotion enhances carburization and increases surface acidity and basicity of the Fe-Zn oxide precursor. While Cu inhibits carburization and decreases the surface acidity and basicity of the Fe-Zn oxide precursor. The implications of these effects on the application of catalysts for FT are discussed.

  12. Materials Science Division coal technology fifth quarterly report, October--December 1975. [Gasification plant materials

    Energy Technology Data Exchange (ETDEWEB)

    None

    1975-01-01

    Results on refractories tested in the slag-corrosion-cup test indicate that attack by acidic slag is less severe than by basic slag. The first (200 h) test in the slag-abrasion-corrosion test rig was completed. Nondestructive tests have been conducted at the CO/sub 2/ Acceptor plant and the HYGAS plant, and an instrumented piping section is being prepared for the Synthane plant. Carburization studies, which have been performed on several alloys, indicate that the extent of carburization increases with an increase in the chromium content of the alloy. Present erosion models predict greater erosion rates than found experimentally, but they assume all particles impact the surface. Failure analyses have been conducted for HYGAS materials, and support in materials identification was given to Synthane plant personnel. (auth)

  13. XPS, XRD and laser Raman analysis of surface modified of 6150 steel substrates for the deposition of thick and adherent diamond-like carbon coatings

    Energy Technology Data Exchange (ETDEWEB)

    Silva, William de Melo; Carneiro, Jose Rubens Goncalves, E-mail: williammelosilva@gmail.com [Pontificia Universidade Catolica de Minas Gerais (PUC-MG), Belo Horizonte (Brazil). Dept. de Engenharia Mecanica; Trava-Airoldi, Vladimir Jesus [Associate Laboratory of Sensors and Materials, National Institute for Space Research, Sao Jose dos Campos, SP (Brazil)

    2013-11-01

    Although the 6150 steel has an excellent fatigue and impact resistance, it is unsuitable to operate it when the corrosion is a limited factor. We propose here a sequence of steel pre-treatment by carburizing, carbonitriding and nitriding in order to improve the poor adhesion between Diamond Like-Carbon coatings on steel. This sequence is our attempt to reduce the difference between the coefficients of thermal expansion of steel and DLC through the graded interface. This work demonstrates the quantitative analysis of the molecules present at surface using X-ray photoelectron spectroscopy. The crystallographic structures are investigated by X-ray diffraction which shows the formation of carbides and nitride phases. Raman spectroscopy reveals the carburizing surface characteristics where DLC coating is nucleated and grown at the substrate. At the end of the analysis it is possible to verify which molecules and phases are formed on the steel surface interface after each step of pre-treatment. (author)

  14. A Feasibility Study on Low Temperature Thermochemical Treatments of Austenitic Stainless Steel in Fluidized Bed Furnace

    Science.gov (United States)

    Haruman, Esa; Sun, Yong; Triwiyanto, Askar; Manurung, Yupiter H. P.; Adesta, Erry Y.

    2011-04-01

    In this work, the feasibility of using an industrial fluidized bed furnace to perform low temperature thermochemical treatments of austenitic stainless steels has been studied, with the aim to produce expanded austenite layers with combined wear and corrosion resistance, similar to those achievable by plasma and gaseous processes. Several low temperature thermochemical treatments were studied, including nitriding, carburizing, combined nitridingcarburizing (hybrid treatment), and sequential carburizing and nitriding. The results demonstrate that it is feasible to produce expanded austenite layers on the investigated austenitic stainless steel by the fluidized bed heat treatment technique, thus widening the application window for the novel low temperature processes. The results also demonstrate that the fluidized bed furnace is the most effective for performing the hybrid treatment, which involves the simultaneous incorporation of nitrogen and carbon together into the surface region of the component in nitrogen and carbon containing atmospheres. Such hybrid treatment produces a thicker and harder layer than the other three processes investigated.

  15. The use of Thermodynamics and Phase Equilibria for Prediction of the Behavior of High Temperature Corrosion of Alloy 617 in Impure Helium Environment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Jin; Lee, Gyeong Geun; Kim, Sung Woo; Kim, Hong Pyo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-08-15

    Thermodynamic consideration was performed for Alloy 617 exposed to an impure helium (H{sub 2} 20pa, H{sub 2}O 0.5pa, CH{sub 3} 2pa and CO 5pa) at 950 .deg. C. Oxidation power was decreased in the order Al > Ti > Si > Cr > Mn. Decarburization and carburization reactions were available leading to carbon activity decrease and increase, respectively, depending on carbon and Cr activities. The thermodynamic prediction was compared with the experimental results obtained in similar conditions ((H{sub 2} 20pa, H{sub 2}O 0.05pa, CH{sub 4} 5pa and CO 2pa) and 950 .deg. C) by others for Alloy 617. The driving force for oxidation of Al, Ti and Si is very large to be oxidized at a given impure helium and the environment is actually carburizing towards the structural alloy, which is consistent with this work.

  16. Synthesis of titanium carbide by induction plasma reactive spray

    Institute of Scientific and Technical Information of China (English)

    JIANG Xian-Liang(蒋显亮); M.Boulos

    2004-01-01

    A novel method capable of sufficient mixing of titanium powder and methane of carbon source was developed in the synthesis of titanium carbide by induction plasma reactive spray. X-ray diffraction analysis, optical microscopy, scanning electron microscopy, and microhardness test were used to characterize the spray-formed deposit.The experimental results show that both primary carburization of the titanium particles inside the plasma flame and secondary carburization of the growing deposit on high temperature substrate contribute to the forming of titanium carbide. The transitional phase of TiC1-x has the same crystal structure as TiC, but has a slightly low lattice constant. The deposit consists of fine grain structure and large grain structure. The fine grain structure, harder than large grain structure, shows grain boundary fracture.

  17. Optimization of Heat Treatment Process for Internal Clutch by Using Taguchi Technique

    Directory of Open Access Journals (Sweden)

    Prof. S. R. Thakare,

    2014-01-01

    Full Text Available Surface engineering and surface engineered materials find wide applications in engineering industries in recent years. Inconsistency in hardness and case depth has resulted in the further optimization of the process variables involved in surface hardening. In the present study, the following operating parameters viz. Carbon potential, holding position, furnace temperature, carburizing time, quenching medium, quenching temperature, quenching time, tempering temperature and tempering time were taken for optimization using the Taguchi and Factorial design of experiment concepts. From the experiments and optimization analysis conducted on EN8 materials it was observed that furnace temperature and quenching time had equal influence in obtaining a better surface integrity of the case hardened components using gas carburizing. In the case of induction hardening process, power potential played a vital role in optimizing the surface hardness and the depth of hardness.

  18. Engineered Coatings for Ni Alloys in High Temperature Reactors

    Science.gov (United States)

    Clark, Elizabeth A.; Yang, James Y.; Kumar, Deepak; Was, Gary S.; Levi, Carlos G.

    2013-02-01

    Alloy 617 is a candidate material for the intermediate heat exchanger of the He-cooled very high temperature reactor. At target temperatures ≥1223 K (950 °C), low level impurities in the gas stream may cause carburization, decarburization, and/or oxidation of 617 with deleterious effects on its mechanical properties. The chromia scale formed naturally by 617 does not provide adequate protection in the expected environment. Alpha alumina offers a greater potential as an effective diffusion barrier with superior stability, but it requires modification of the alloy surface. This work explores two approaches to surface modification based on aluminizing, either alone or in combination with FeCrAlY cladding, followed by pre-oxidation to form alpha alumina. Both approaches yield coatings with promising diffusional stability on alloy 617. Initial corrosion studies in impure He environments reveal that the alpha alumina is stable and protects the underlying substrate in both carburizing and decarburizing environments.

  19. XPS, XRD and laser raman analysis of surface modified of 6150 steel substrates for the deposition of thick and adherent diamond-like carbon coatings

    Directory of Open Access Journals (Sweden)

    William de Melo Silva

    2013-06-01

    Full Text Available Although the 6150 steel has an excellent fatigue and impact resistance, it is unsuitable to operate it when the corrosion is a limited factor. We propose here a sequence of steel pre-treatment by carburizing, carbonitriding and nitriding in order to improve the poor adhesion between Diamond Like-Carbon coatings on steel. This sequence is our attempt to reduce the difference between the coefficients of thermal expansion of steel and DLC through the graded interface. This work demonstrates the quantitative analysis of the molecules present at surface using X-ray photoelectron spectroscopy. The crystallographic structures are investigated by X-ray diffraction which shows the formation of carbides and nitride phases. Raman spectroscopy reveals the carburizing surface characteristics where DLC coating is nucleated and grown at the substrate. At the end of the analysis it is possible to verify which molecules and phases are formed on the steel surface interface after each step of pre-treatment.

  20. Properties of 15HN Steel after Various Thermo-Chemical Treatments

    Directory of Open Access Journals (Sweden)

    L. Klimek

    2007-07-01

    Full Text Available The aim of conducted research was to find universal steel that may serve to regenerate machine elements by MULTIPLEX method – or cladding of alloy steel and then subjecting to thermo-chemical treatment. This paper presents the results of metallographic examination, hardness distribution and selected tribological properties of vacuum carburized, sulphonitrided and vacuum nitrided layers obtained on 15HN steel. The results demonstrate that on 15HN steel (carburizing steel, nitrided and sulphonitrided layers show good durability and tribological properties. Therefore, it is possible to use it to regenerate machine elements by cladding method and then treat them by different thermo-chemical ways in order to obtain desired properties.

  1. Characterization and refinement of carbide coating formation rates and dissolution kinetics in the Ta-C system

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Patrick James [Univ. of New Mexico, Albuquerque, NM (United States)

    1996-10-01

    The interaction between carbide coating formation rates and dissolution kinetics in the tantalum-carbon system was investigated. The research was driven by the need to characterize carbide coating formation rates. The characterization of the carbide coating formation rates was required to engineer an optimum processing scheme for the fabrication of the ultracorrosion-resistant composite, carbon-saturated tantalum. A packed-bed carburization process was successfully engineered and employed. The packed-bed carburization process produced consistent, predictable, and repeatable carbide coatings. A digital imaging analysis measurement process for accurate and consistent measurement of carbide coating thicknesses was developed. A process for removing the chemically stable and extremely hard tantalum-carbide coatings was also developed in this work.

  2. Evaluation of Microstructure and Wear Properties of Ti-6Al-4V Alloy Plasma Carbonized at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yong; WEI Qiulan; XING Yazhe; JIANG Chaoping; LI Xinghang; ZHAO Zhiyu

    2015-01-01

    Ti-6Al-4V (TC4) alloys were plasma carbonized at different temperatures (900, 950, and 1 000ć) for duration of 3 h. Graphite rod was employed as carbon supplier to avoid the hydrogen brittleness which is ubiquitous in traditional gas carbonizing process. Two distinguished structures including a thin compound layer (carbides layer) and a thick layer with the mixed microstructure of TiC and theα-Ti in carburing layer were formed during carburizing. Furthermore, it was found that the microstructure and the properties of TC4 alloy were signifi cantly related to the carbonizing temperature. The specimen plasma carbonized at 950ć obtained maximum value both in the hardness and wear resistance.

  3. Influence of different thermal treatment in sintered steels base molybdenum; Influencia de diferentes tratamientos termoquimicos en aceros sinterizados base molibdeno

    Energy Technology Data Exchange (ETDEWEB)

    Candela, N.; Plaza, R.; Ruiz-Amador, D.; Velasco, F.; Torralba, J. M.

    2001-07-01

    Prealloyed steel powders with different amount of Mo-Cu-Ni-C were compacted at 700 MPa and sintered at 1120 degree centigree in 95% N{sub 2} -5% H{sub 2}. After sinterizing, these materials were treated by carburizing. For materials characterization radial crushing strength were preformed, density was calculated and a complete study of fracture surfaces was carried out using scanning electron microscopy. The results of radial crushing strength show that resistance after carburizing is higher than in sintered materials. The fracture surfaces give an idea of materials briteless and the treatment depth. In sintered materials, a ductil surface was observed, with the characteristic dimples. The fracture surfaces after different treatments show brittleness in the outer zone, while appears a mix of ductil and briteless fracture. (Author) 7 refs.

  4. Thermodynamics of hydrogen production with the thermal oxidative method

    Energy Technology Data Exchange (ETDEWEB)

    Tabakaeva, L.S. (Sektor Mekhaniki Neodnorodnykh Sred AN SSSR (USSR))

    1990-07-01

    Investigates interaction processes between steam and iron ore containing 98.45% Fe{sub 3}O{sub 4}, utilizing brown coal from the Kansk-Achinsk basin as reducer. An algorithm based on the maximum entropy principle was employed to determine equilibrium conditions of the isolated system. Reduction requires additional energy provided by coal combustion. High-temperature FeO-yielding reduction decreases coal consumption. For Fe-yielding reduction, higher temperature also decreases coal consumption, but above 1,100 K slowly increases it again. Carbide-formation and carburization should be avoided. Iron ore reduction should occur in the presence of FeO. The maximum possible FeO yield without carbide-formation and carburation is in the temperature range of 900-1,500 K. 13 refs.

  5. Bending Fatigue Strength of Austempered Ductile Iron Spur Gears

    Science.gov (United States)

    Yamanaka, Masashi; Tamura, Ryo; Inoue, Katsumi; Narita, Yukihito

    This paper deals with an experimental evaluation of bending fatigue strength for austempered ductile iron (ADI) spur gears. The module is 2.5 and the number of teeth is 26 in the test gears. The material of the test gears corresponds to Japan Industrial Standard (JIS) FCAD1100-15. Some gears are processed by one of two types of fine particle bombarding (FPB). The surface roughness is slightly increased by FPB. The obtained strengths are 623 MPa for the as-austempered gears, and 1011 and 1085 MPa for the gears after FPB. The strength is expressed by the fillet stress level, which is calculated by FEM. The strength of a gear with the same dimensions made of carburized SCr420H alloy steel is 1205 MPa, and the strength of the ADI gear is approximately half that of the carburized steel gear. The FPB process has a significant effect on the ADI gear, improving its strength by 62-74%.

  6. Synthesis and characterization of binder-free Cr{sub 3}C{sub 2} coatings on nickel-based alloys for molten fluoride salt corrosion resistance

    Energy Technology Data Exchange (ETDEWEB)

    Brupbacher, Michael C.; Zhang, Dajie [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Buchta, William M. [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Graybeal, Mark L. [U.S. Army Research Laboratory, Aberdeen Proving Ground, MD 21005 (United States); Rhim, Yo-Rhin [The Johns Hopkins University Applied Physics Laboratory, 11100 Johns Hopkins Road, Laurel, MD 20723 (United States); Nagle, Dennis C. [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Spicer, James B., E-mail: spicer@jhu.edu [Department of Materials Science and Engineering, The Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States)

    2015-06-15

    Under various conditions, chromium carbides appear to be relatively stable in the presence of molten fluoride salts and this suggests that their use in corrosion resistant coatings for fluoride salt environments could be beneficial. One method for producing these coatings is the carburization of sprayed Cr coatings using methane-containing gaseous precursors. This process has been investigated for the synthesis of binder-free chromium carbide coatings on nickel-based alloy substrates for molten fluoride salt corrosion resistance. The effects of the carburization process on coating microstructure have been characterized using X-ray diffraction (XRD) and scanning electron microscopy (SEM) in conjunction with energy dispersive spectroscopy (EDS). Both plasma-sprayed and cold-sprayed Cr coatings have been successfully converted to Cr{sub 3}C{sub 2}, with the mechanism of conversion being strongly influenced by the initial porosity in the as-deposited coatings.

  7. Development of Barrier Layers for the Protection of Candidate Alloys in the VHTR

    Energy Technology Data Exchange (ETDEWEB)

    Levi, Carlos G. [Battelle Energy Alliance, LLC, Idaho Falls, ID (United States); Jones, J. Wayne [Battelle Energy Alliance, LLC, Idaho Falls, ID (United States); Pollock, Tresa M. [Battelle Energy Alliance, LLC, Idaho Falls, ID (United States); Was, Gary S. [Battelle Energy Alliance, LLC, Idaho Falls, ID (United States)

    2015-01-22

    The objective of this project was to develop concepts for barrier layers that enable leading candi- date Ni alloys to meet the longer term operating temperature and durability requirements of the VHTR. The concepts were based on alpha alumina as a primary surface barrier, underlay by one or more chemically distinct alloy layers that would promote and sustain the formation of the pro- tective scale. The surface layers must possess stable microstructures that provide resistance to oxidation, de-carburization and/or carburization, as well as durability against relevant forms of thermo-mechanical cycling. The system must also have a self-healing ability to allow endurance for long exposure times at temperatures up to 1000°C.

  8. Effect of incorporation manner of Zr promoter on precipitated ironbased catalysts for Fischer-Tropsch synthesis

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao-jian; MA Hong-fang; ZHANG Hai-tao; YING Wei-yong; FANG Ding-ye

    2012-01-01

    The promotional effects of Zr on the structure,reduction,carburization and catalytic behavior of precipitated iron-based Fischer-Tropsch synthesis (FTS) catalysts were investigated.The catalysts were characterized by N2 physisorption,temperature-programmed reduction (TPR),and M(o)ssbauer effect spectroscopy (MES) techniques.As revealed by N2 physisorption,Zr decreased the BET surface area and pore volume of the catalyst.The results of TPR and MES show that Zr suppresses the reduction and carburization of Fe catalysts because of the interaction between Fe and Zr.The FTS reaction results indicate that Zr decreases the FTS activity of Fe catalysts but improves the catalysts' stability.In addition,Zr promoter restraines the formation of light hydrocarbons (methane and C2~C4) and shifts the production distribution to the heavy hydrocarbons.

  9. Low leaded motor gasoline of high knock rating having few pollution effects

    Energy Technology Data Exchange (ETDEWEB)

    Droste, W.; Obenaus, F.; Schoefer, W.

    1975-11-13

    A carburator gasoline has been developed that has a high knock rating and few enviromental pollution effects. The gasoline contains 0.1 to 0.4 g of lead per liter, and up to 20 percent by volume of a mixture made up of 80 to 90 percent by weight methyl-tert.-butyl ether and 20 to 10 percent by weight methanol. Through tests it has been determined that the characteristics (particularly the octane number) of a gasoline having a lead content of 0.15 g/liter and one of the above mentioned additives are better than those of a gasoline with a lead content of 0.4 g/liter, but not containing an additive. The harmful emissions were also lower. In addition, the danger of carburator icing is decreased.

  10. Preparation and thermodynamics characterization of micro-porous TiC%TiC微孔陶瓷的制备及其热力学表征

    Institute of Scientific and Technical Information of China (English)

    罗勇; 田茂财; 杨莉

    2012-01-01

    Material thermodynamics is used to analyze the carburization of titanium alloy for the purpose of research on the formation mechanism of micro-porous TiC ceramics. And then TiC miero-porous ceramics are successfully synthesized on the surface of titanium alloys using se- quential carburization. Finally, the properties of micro-porous TiC ceramics are examined. It is found that the sequential carburization is thermodynamically feasible, and graphite is obtained after the carburization. It also reveals that the high hardness could provide excellent support to the titanium alloy substrate. The results show that compact micro-porous titanium carbide with a face-centred cubic structure has high hardness value of 16.1 GPa, which indicates that micro --porous TiC ceramics is a potential biomaterial due to its excellent protection of the titanium substrate.%为了研究TiC微孔陶瓷的形成机理,采用材料热力学分析了钛合金的渗碳工艺,采用分级渗碳法在钛合金表面制备出了TiC微孔陶瓷,并对微孔陶瓷进行了性能表征.研究后认为钛合金分级渗碳在热力学上可行,同时在分级渗碳中得到的是石墨碳;其硬度很高能够对钛合金形成很好的支撑作用.结果表明:面心立方结构的碳化钛微孔陶瓷的纳米硬度值达到了16.1GPa,将对钛合金基体起到很好的保护作用,是一种很有前途的生物材料.

  11. Crystal-phase control of molybdenum carbide nanobelts for dehydrogenation of benzyl alcohol.

    Science.gov (United States)

    Li, Zhongcheng; Chen, Chunhui; Zhan, Ensheng; Ta, Na; Li, Yong; Shen, Wenjie

    2014-05-04

    Belt-shaped molybdenum carbides in α- and β-phases were synthesized by reducing and carburizing a nano-sized α-MoO3 precursor with hydrocarbon-hydrogen mixtures at appropriate temperatures; the β-Mo2C nanobelts with a higher fraction of coordinatively unsaturated Mo sites were more active than the α-MoC1-x nanobelts in dehydrogenation of benzyl alcohol to benzaldehyde.

  12. Role of Steel Object Surface Condition on Behavior During Deformation

    Science.gov (United States)

    D'yachenko, S. S.; Ponomarenko, I. V.; Dub, S. N.

    2015-09-01

    Comparative analysis is provided for specimen mechanical properties of steels 18KhGT and 20Kh with tensile testing in relation to surface treatment: grinding, polishing, nitriding, carburizing, and ion-plasma treatment. It is shown that surface condition has a considerable effect on specimen behavior during deformation. It is established that the most favorable effect applies to ion bombardment with low-energy ions recommended as an effective method for improving component structural strength.

  13. Growth of bridging carbon nanofibers in cracks formed by heat-treating iron oxide thin sheets in acetylene gas

    Directory of Open Access Journals (Sweden)

    Takeshi Hikata

    2013-04-01

    Full Text Available We produced novel carbon nanofibers (CNFs by oxidizing high-purity iron foil and then carburizing it in acetylene gas flow. This formed cracks in the heat-treated iron foil with CNFs bridging the two walls of each crack. The CNFs were drawn out from the walls as the crack opened during heat treatment. This will be a new method to grow and arrange carbon nanotubes and nanosheets without using metal nanoparticles or template substrates.

  14. 油润滑

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Modeling of the inlet zone in the mixed lubrication situation of cold strip rolling;Fatigue Behavior of ltybrid Ceramic Ball Bearings in Liquid Nitrogen;EHL film thickness limitation theory under a limiting shear stress;Effects of Surlace Roughness on Behaviors of Lubricant Molecules in Ultra-Thin Fihn Lubrication;Effect of slip condition on the contact fatigue strength for pitting of the carburized steel。

  15. Growth of bridging carbon nanofibers in cracks formed by heat-treating iron oxide thin sheets in acetylene gas

    Science.gov (United States)

    Hikata, Takeshi; Okubo, Soichiro; Higashi, Yugo; Matsuba, Teruaki; Utsunomiya, Risa; Tsurekawa, Sadahiro; Murakami, Katsuhisa; Fujita, Jun-ichi

    2013-04-01

    We produced novel carbon nanofibers (CNFs) by oxidizing high-purity iron foil and then carburizing it in acetylene gas flow. This formed cracks in the heat-treated iron foil with CNFs bridging the two walls of each crack. The CNFs were drawn out from the walls as the crack opened during heat treatment. This will be a new method to grow and arrange carbon nanotubes and nanosheets without using metal nanoparticles or template substrates.

  16. Mechanism and Influencing Factors of Iron Nuggets Forming in Rotary Hearth Furnace Process at Lower Temperature

    Science.gov (United States)

    Han, Hongliang; Duan, Dongping; Chen, Siming; Yuan, Peng

    2015-10-01

    In order to improve the efficiency of slag and iron separation, a new idea of "the separation of slag (solid state) and iron (molten state) in rotary hearth furnace process at lower temperature" is put forward. In this paper, the forming process of iron nuggets has been investigated. Based on those results, the forming mechanisms and influencing factors of iron nugget at low temperature are discussed experimentally using an electric resistance furnace simulating a rotary hearth furnace process. Results show that the reduction of iron ore, carburization of reduced iron, and the composition and quantity of slag are very important for producing iron nuggets at lower temperature. Reduction reaction of carbon-containing pellets is mainly at 1273 K and 1473 K (1000 °C and 1200 °C). When the temperature is above 1473 K (1200 °C), the metallization rate of carbon-containing pellets exceeds 93 pct, and the reduction reaction is substantially complete. Direct carburization is the main method for carburization of reduced iron. This reaction occurs above 1273 K (1000 °C), with carburization degree increasing greatly at 1473 K and 1573 K (1200 °C and 1300 °C) after particular holding times. Besides, to achieve the "slag (solid state) and iron (molten state) separation," the melting point of the slag phase should be increased. Slag (solid state) and iron (molten state) separation can be achieved below 1573 K (1300 °C), and when the holding time is 20 minutes, C/O is 0.7, basicity is less than 0.5 and a Na2CO3 level of 3 pct, the recovery rate of iron can reach 90 pct, with a proportion of iron nuggets more than 3.15 mm of nearly 90 pct. This study can provide theoretical and technical basis for iron nugget production.

  17. 滚刀

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Helix gash of hob cutter manufactured by milling,Hob cutting profile deviation of gear coupling-pinion,INFLUENCE OF THE CUTTING SCHEME ON GEAR MILLING ACCURACY, On a possible way of size and weight reduction of a car transmission,Performance of skiving hobs in finishing induction hardened and carburized gears,Precision grinding of helical gashes for hob cutters,Simulation modeling and optimization of stockyard layouts for precast concrete products.

  18. Carbon Coating Of Copper By Arc-Discharge Pyrolysis

    Science.gov (United States)

    Ebihara, Ben T.; Jopek, Stanley

    1988-01-01

    Adherent, abrasion-resistant coat deposited with existing equipment. Carbon formed and deposited as coating on copper substrate by pyrolysis of hydrocarbon oil in electrical-arc discharges. Technique for producing carbon deposits on copper accomplished with electrical-discharge-machining equipment used for cutting metals. Applications for new coating technique include the following: solar-energy-collecting devices, coating of metals other than copper with carbon, and carburization of metal surfaces.

  19. Active carbon supported molybdenum carbides for higher alcohols synthesis from syngas

    DEFF Research Database (Denmark)

    Wu, Qiongxiao; Chiarello, Gian Luca; Christensen, Jakob Munkholt

    This work provides an investigation of the high pressure CO hydrogenation to higher alcohols on K2CO3 promoted active carbon supported molybdenum carbide. Both activity and selectivity to alcohols over supported molybdenum carbides increased significantly compared to bulk carbides in literatures....... spectroscopy were applied for determining the carburization temperature and evaluating the composition of the carbide clusters of different samples through determinations of the Mo-C and Mo-Mo coordination numbers....

  20. Effect of ferroalloy gas purification rate on kinetics of red mud carbonization

    OpenAIRE

    Кириченко, Олексій Геннадійович

    2013-01-01

    The process of iron carburization by CO-containing gases of ferroalloy furnaces using as catalyst materials red mud from alumina production.Red mud from alumina production and waste gases ferroalloy furnaces after appropriate training are quite suitable for the decomposition reaction of carbon monoxide. Ferroalloy gas sulfur compounds have toxic effect on the catalytic ability of the red mud. The most effective absorber catalyst poisons in the experiments was a solution of potassium permangan...

  1. Simulation of creep test on 316FR stainless steel in sodium environment at 550degC

    Energy Technology Data Exchange (ETDEWEB)

    Satmoko, A. [National Atomic Energy Agency, BATAN (Indonesia); Asayama, Tai

    1999-04-01

    In sodium environment, material 316FR stainless steel risks to suffer from carburization. In this study, an analysis using a Fortran program is conducted to evaluate the carbon influence on the creep behavior of 316FR based on experimental results from uni-axial creep test that had been performed at temperature 550degC in sodium environment simulating Fast Breeder Reactor condition. As performed in experiments, two parts are distinguished. At first, elastic-plastic behavior is used to simulate the fact that just before the beginning of creep test, specimen suffers from load or stress much higher than initial yield stress. In second part, creep condition occurs in which the applied load is kept constant. The plastic component should be included, since stresses increase due to section area reduction. For this reason, elastic-plastic-creep behavior is considered. Through time carbon penetration occurs and its concentration is evaluated empirically. This carburization phenomena are assumed to affect in increasing yield stress, decreasing creep strain rate, and increasing creep rupture strength of material. The model is capable of simulating creep test in sodium environment. Material near from surface risks to be carburized. Its material properties change leading to non-uniform distribution of stresses. Those layers of material suffer from stress concentration, and are subject to damage. By introducing a damage criteria, crack initialization can thus be predicted. And even, crack growth can be evaluated. For high stress levels, tensile strength criterion is more important than creep damage criterion. But in low stress levels, the latter gives more influence in fracture. Under high stress, time to rupture of a specimen in sodium environment is shorter than in air. But for stresses lower than 26 kgf/mm{sup 2}, the time to rupture of creep in sodium environment is the same or little longer than in air. Quantitatively, the carburization effect at 550degC is not important

  2. Long Term Out-of-pile Thermocouple Tests in Conditions Representative for Nuclear Gas-cooled High Temperature Reactors

    OpenAIRE

    LAURIE Mathias; FOURREZ Stephane; FUETTERER Michael; LAPETITE Jean-Marc

    2011-01-01

    During irradiation tests at high temperature, failure of commercial Inconel 600 sheathed thermocouples is commonly encountered. To understand and remediate this problem, out-ofpile tests were performed with thermocouples in carburizing atmospheres which can be assumed to be at least locally representative for High Temperature Reactors. The objective was to screen those thermocouples which would consecutively be used under irradiation. Two such screening tests have been performed with a set of...

  3. La présentation des réglementations de IGH (immeuble de grande hauteur, Skyskrapers, High Rise Building) fran aises

    Institute of Scientific and Technical Information of China (English)

    Wajdi Laroussi; XING Wei

    2014-01-01

    Résumé: Présenter les réglementations IGH fran aises portant sur les exigences et la notion d’évacuation complète, le niveau d’anti-incendie pour les c bles, la réserve du carburant des génératrices, l’application du système informatique etc. Comparer-les avec celles de l’Allemagne et des Etats-unis.

  4. 85th anniversary of the "metal science and heat treatment" chair of the N. É. Bauman Moscow State Technical University

    Science.gov (United States)

    Smirnov, A. E.; Rodionov, A. V.; Ryzhov, N. M.

    1994-06-01

    An automated control system for a production process (ACS PP) of ionic casehardening (CH) on the basis of the specialized "Orion-4" control complex is discussed in the paper. The temperature of the charge of components, the power of the glow discharge, the pressure, and the carburizing and nitriding capacity of the production atmosphere ensures high stability of casehardening results, the attainment of diffusion layers that are uniform over the profile of the component, and the prescribed degree of their saturation.

  5. WC as a non-platinum hydrogen evolution electrocatalyst for high temperature PEM water electrolysers

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik

    2012-01-01

    Tungsten carbide (WC) nanopowder was tested as a non-platinum cathode electrocatalyst for polymer electrolyte membrane (PEM) water electrolysers, operating at elevated temperatures. It was prepared in thermal plasma reactor with confined plasma jet from WO3 precursor in combination with CH4...... carburizing agent. The results of the investigation showed that the activity of tungsten carbide as cathode electrocatalyst increases significantly with temperature and this effect is more pronounced than for platinum, especially, at 150 °C....

  6. Preparation and Characterization of Niobium Carbide and Carbonitride

    Science.gov (United States)

    Kim, Hak Soo; Bugli, Guy; Djéga-Mariadassou, Gérald

    1999-01-01

    Unsupported niobium carbide powders of NbC were prepared by carburization of commercial niobium pentoxide in flowing CH4-H2mixtures. Several routes of synthesis were investigated, leading to final carbides with specific surface areas ranging from 10 to 50 m2g-1. During direct carburization, after the first step of reduction of Nb2O5to NbO2, a long induction period which was succeeded by an acceleratory period, was observed for the reduction/carburization to NbC. In the presence of a catalyst of methane decomposition, this induction period was eliminated but the superficial carbon free contamination of the final carbide was increased. However, this contamination can be removed by a reducing treatment and CO chemisorption can be observed. The preparations through niobium oxynitride lead to face-centered cubic carbonitrides with specific surface areas ranging from 27 to 49 m2g-1. Chemical composition and cell parameter of these cabonitrides vary slightly with the synthesis conditions. After a reducing treatment, as for NbC, CO chemisorption was also observed.

  7. An Investigation on Low-Temperature Thermochemical Treatments of Austenitic Stainless Steel in Fluidized Bed Furnace

    Science.gov (United States)

    Haruman, E.; Sun, Y.; Triwiyanto, A.; Manurung, Y. H. P.; Adesta, E. Y.

    2012-03-01

    In this study, the feasibility of using an industrial fluidized bed furnace to perform low-temperature thermochemical treatments of austenitic stainless steels has been studied, with the aim to produce expanded austenite layers with combined wear and corrosion resistance, similar to those achievable by plasma and gaseous processes. Several low-temperature thermochemical treatments were studied, including nitriding, carburizing, combined nitriding-carburizing (hybrid treatment), and sequential carburizing and nitriding. The results demonstrate that it is feasible to produce expanded austenite layers on the investigated austenitic stainless steel by the fluidized bed heat treatment technique, thus widening the application window for the novel low-temperature processes. The results also demonstrate that the fluidized bed furnace is the most effective for performing the hybrid treatment, which involves the simultaneous incorporation of nitrogen and carbon together into the surface region of the component in nitrogen- and carbon-containing atmospheres. Such hybrid treatment produces a thicker and harder layer than the other three processes investigated.

  8. Corrosion resistance of kolsterised austenitic 304 stainless steel

    Science.gov (United States)

    Abudaia, F. B.; Khalil, E. O.; Esehiri, A. F.; Daw, K. E.

    2015-03-01

    Austenitic stainless suffers from low wear resistance in applications where rubbing against other surfaces is encountered. This drawback can be overcome by surface treatment such as coating by hard materials. Other treatments such as carburization at relatively low temperature become applicable recently to improve hardness and wear resistance. Carburization heat treatment would only be justified if the corrosion resistance is unaffected. In this work samples of 304 stainless steels treated by colossal supersaturation case carburizing (known as Kolsterising) carried out by Bodycote Company was examined for pitting corrosion resistance at room temperature and at 50 °C. Comparison with results obtained for untreated samples in similar testing conditions show that there is no deterioration in the pitting resistance due to the Kolsterising heat treatment. X ray diffraction patterns obtained for Kolsterising sample showed that peaks correspond to the austenite phase has shifted to lower 2θ values compared with those of the untreated sample. The shift is an indication for expansion of austenite unit cells caused by saturation with diffusing carbon atoms. The XRD of Kolsterising samples also revealed additional peaks appeared in the patterns due to formation of carbides in the kolsterised layer. Examination of these additional peaks showed that these peaks are attributed to a type of carbide known as Hagg carbide Fe2C5. The absence of carbides that contain chromium means that no Cr depletion occurred in the layer and the corrosion properties are maintained. Surface hardness measurements showed large increase after Kolsterising heat treatment.

  9. Mathematical Model of ComputerHeat Treatment and Its Simulation

    Institute of Scientific and Technical Information of China (English)

    PanJiansheng; ZhangWeimin; TianDong; GuJianfeng; HuMingjuan

    2004-01-01

    Computer simulation on heat treatment is the foundation of intelligent heat treatment. The simulations of temperature field,phase transformation, stress/strain complicate quenching operation were realized by using the model of three dimensional non-linear finite element method and the treatment methods of abruptly changing interface conditions. The simulation results basically fit those measured in experiments. The intelligent sealed multipurpose furnace production line has been developed based on the combination of computer simulation on gaseous carburizing and computer control technology. More than 3000 batches of workpieces have been processed on this production line, and all are up to standard. The application of computer simulation technology can significantly improve the loading ability and reliability of nitriding and carburizing workpieces, reduce heat treatment distortion, and shorten carburizing duration. It is recommended that the reliable product design without redundancy should be performed with the combination of the CAD of mechanical products, the CAE of materials selection and heat treatment, and the dynamic evaluation technology of product reliability.

  10. Corrosion resistance of kolsterised austenitic 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Abudaia, F. B., E-mail: fabudaia@yahoo.com; Khalil, E. O., E-mail: ekhalil9@yahoo.com; Esehiri, A. F., E-mail: Hope-eseheri@hotmail.co.uk; Daw, K. E., E-mail: Khawladaw@yahoo.com [University of Tripoli Department of Materials and Metallurgical Eng, Tripoli-Libya P.O.Box13589 (Libya)

    2015-03-30

    Austenitic stainless suffers from low wear resistance in applications where rubbing against other surfaces is encountered. This drawback can be overcome by surface treatment such as coating by hard materials. Other treatments such as carburization at relatively low temperature become applicable recently to improve hardness and wear resistance. Carburization heat treatment would only be justified if the corrosion resistance is unaffected. In this work samples of 304 stainless steels treated by colossal supersaturation case carburizing (known as Kolsterising) carried out by Bodycote Company was examined for pitting corrosion resistance at room temperature and at 50 °C. Comparison with results obtained for untreated samples in similar testing conditions show that there is no deterioration in the pitting resistance due to the Kolsterising heat treatment. X ray diffraction patterns obtained for Kolsterising sample showed that peaks correspond to the austenite phase has shifted to lower 2θ values compared with those of the untreated sample. The shift is an indication for expansion of austenite unit cells caused by saturation with diffusing carbon atoms. The XRD of Kolsterising samples also revealed additional peaks appeared in the patterns due to formation of carbides in the kolsterised layer. Examination of these additional peaks showed that these peaks are attributed to a type of carbide known as Hagg carbide Fe{sub 2}C{sub 5}. The absence of carbides that contain chromium means that no Cr depletion occurred in the layer and the corrosion properties are maintained. Surface hardness measurements showed large increase after Kolsterising heat treatment.

  11. The Study of Heat Treatment Effects on Chromium Carbide Precipitation of 35Cr-45Ni-Nb Alloy for Repairing Furnace Tubes

    Directory of Open Access Journals (Sweden)

    Nakarin Srisuwan

    2016-01-01

    Full Text Available This paper presents a specific kind of failure in ethylene pyrolysis furnace tubes. It considers the case in which the tubes made of 35Cr-45Ni-Nb high temperature alloy failed to carburization, causing creep damage. The investigation found that used tubes became difficult to weld repair due to internal carburized layers of the tube. The microstructure and geochemical component of crystallized carbide at grain boundary of tube specimens were characterized by X-ray diffractometer (XRD, scanning electron microscopy (SEM with back-scattered electrons mode (BSE, and energy dispersive X-ray spectroscopy (EDS. Micro-hardness tests was performed to determine the hardness of the matrix and the compounds of new and used tube material. The testing result indicated that used tubes exhibited a higher hardness and higher degree of carburization compared to those of new tubes. The microstructure of used tubes also revealed coarse chromium carbide precipitation and a continuous carbide lattice at austenite grain boundaries. However, thermal heat treatment applied for developing tube weld repair could result in dissolving or breaking up chromium carbide with a decrease in hardness value. This procedure is recommended to improve the weldability of the 35Cr-45Ni-Nb used tubes alloy.

  12. BioTfueL Project: Targeting the Development of Second-Generation Biodiesel and Biojet Fuels Le projet BioTfueL : un projet de développement de biogazole et biokérosène de 2 génération

    Directory of Open Access Journals (Sweden)

    Viguié J.-C.

    2013-10-01

    Full Text Available 2nd generation biofuels will have an important part to take in the energy transition as far as fuels are concerned. Using non edible biomass, they will avoid any direct competition with food usage. Within 2nd generation biofuels, the BTL route consists in the production of middle distillates (Diesel and jet fuel via gasification and Fischer-Tropsch (FT synthesis. These fuels are called “drop in” fuels; this means that to be used they technically do not request any modification in the vehicle whatever the blending rate with conventional fuels. This route is currently at the pre-industrial phase where demonstration is required. This article presents the BioTfueL project which has been created by Axens, CEA, IFP Energies nouvelles, Sofiprotéol, ThyssenKrupp Uhde and Total. This project is focused on the original concept of co-processing (biomass can be gasified together with fossil feedstock and proposes to develop and demonstrate a full process chain to be commercialized worldwide via licensing. Les biocarburants de 2e génération ont un rôle important à jouer en ce qui concerne le pool carburant dans le cadre de la transition énergétique. Utilisant comme matière première de la biomasse non comestible, ces carburants éviteront toute compétition directe avec un usage alimentaire de cette ressource. Parmi les biocarburants de 2e génération, la voie BTL consiste en la production de distillats moyens (gazole moteur et carburéacteur via gazéification et synthèse Fischer-Tropsch (FT. Ces carburants sont communément appelés des « drop in fuels », ce qui signifie que techniquement ils ne nécessitent aucune modification du véhicule quelque soit leur taux d’incorporation dans les carburants traditionnels. Cette voie entre actuellement en phase préindustrielle pour laquelle une démonstration est nécessaire. Cet article présente le projet BioTfueL qui est porté par Axens, le CEA, IFP Energies nouvelles, Sofiprotéol, Thyssen

  13. Study of the sulfur mechanism on the formation of coke deposition on iron surfaces; Etude des mecanismes d'action du soufre sur le cokage catalytique du fer

    Energy Technology Data Exchange (ETDEWEB)

    Bonnet, F.

    2001-12-01

    The formation of coke deposition which occurs in a range of temperature 500 deg C-650 deg C is a major problem in many chemical and petrochemical processes where hydrocarbons or other strongly carburizing atmospheres are involved. To reduce the rate of coke deposition, sulfur can be added in the gas phase. The topic of this work is to study the sulfur mechanism on the formation of coke deposition on iron surfaces. Firstly, we study the mechanism of graphitic filament formation on reduced and oxidised iron surfaces. A new mechanism of catalytic particle formation is proposed when the surface is initially oxidised. This mechanism is based on thermodynamic, kinetic and structural considerations. The results show that oxide/carbide transitions are involved in the transformation of the oxide layer in catalytic particles. Although the different iron oxides are precursors for the formation of catalytic particles, wustite (FeO) has a better reactivity than magnetite (Fe{sub 3}O{sub 4}) and hematite (Fe{sub 2}O{sub 3}). Sulfur acts on different steps of the coke formation, preventing phase transformations (carburation, graphitization) which occur during the formation of catalytic particles. Sulfur activity required to prevent these transformations changes with the temperature, the chemical state of iron (reduced or oxidised) and the carbon activity in the gas phase. Sulfur/ethylene co-adsorption studies were performed on mono-crystal of iron (110). The results show that sulfur can prevent adsorption and decomposition of this hydrocarbon on metallic surface (Fe) and on magnetite (Fe{sub 3}O{sub 4}). Then, sulfur prevents the reaction leading to the carburation and graphitization of the surface. (author)

  14. Effects of aging in high temperature helium environments on room temperature tensile properties of nickel-base superalloys

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Daejong [Department of Nuclear and Quantum Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Nuclear Materials Technology Development Division, KAERI, 150 Deogjin-dong, Yuseong-gu, Daejeon 305-600 (Korea, Republic of); Sah, Injin [Department of Nuclear and Quantum Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of); Jang, Changheui, E-mail: chjang@kaist.ac.kr [Department of Nuclear and Quantum Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon 305-701 (Korea, Republic of)

    2011-01-25

    Research highlights: {yields} Haynes 230 is susceptible to carburization, but Alloy 617 to decarburization and inter-granular oxidation. {yields} Decarburization of Nickel-base superalloys can be accelerated in impure helium with H{sub 2}. {yields} Aging heat treatment causes inter-granular fracture primarily along inter-granular oxide and grain boundary carbides, which results in the loss of ductility. {yields} Thin-plate specimen of Alloy 617 tends to favor failure by glide plane fracture when it is heavily decarburized. - Abstract: The influence of high temperature aging treatment on room temperature tensile properties of wrought nickel-base superalloys Alloy 617 and Haynes 230 was investigated. A significant decrease in elongation was observed for Alloy 617 exposed to a heavily oxidizing and decarburizing condition because of coarsening of grain boundary carbides and extensive inter-granular oxidation. On the other hand, Haynes 230 showed much lower ductility when exposed to a heavily carburizing condition, especially at 1000 deg. C because extensive carburization occurred due to a reaction with tungsten. Considerable loss of ductility for Alloy 617 and Haynes 230 was also observed in He-H{sub 2}-H{sub 2}O-CO-CO{sub 2}-CH{sub 4} and He-H{sub 2}O-CO-CO{sub 2} environments, which were the slightly oxidizing and decarburizing conditions. Loss of ductility was predominantly associated with brittle inter-granular cracking, while the extent of loss of ductility decreased depending on the decarburization depth. Decarburization was observed more extensively in helium with H{sub 2}-H{sub 2}O-CO-CO{sub 2}-CH{sub 4} than helium with H{sub 2}O-CO-CO{sub 2}, and for Alloy 617 than for Haynes 230. Finally, the role of H{sub 2} in accelerating decarburization is discussed.

  15. Softening Behavior of Hardness and Surface Fatigue of Rolling-Sliding Contact in the Case of Developed Alloy Steels

    Science.gov (United States)

    Redda, Daniel Tilahun; Nakanishi, Tsutomu; Deng, Gang

    To get high performance, downsizing and weight saving of the power transmission systems, the improvement of machine elements has been required. In this study, case-carburized gear materials for a high load-carrying capacity were developed. Low-alloyed steels with 1%Cr-0.2%Mo, 1%Cr-0.2%Mo-1%Si and 1%Cr-0.2%Mo-2%Ni (Cr-Mo steel, Cr-Mo-Si steel and Cr-Mo-Ni steel) were melted in a hypoxia vacuum. Test rollers were made of the developed steels, and they were carburized (Type A and Type B), hardened and tempered. Heating retention tests were carried out to investigate the softening behavior of hardness at high heating temperatures in the case of the developed steels. Roller tests were conducted under the rolling-sliding contact and high-load conditions to study the surface fatigue of the developed steels. From the obtained test results, it was found that the softening behavior of surface hardness at high temperatures in the cases of Cr-Mo-Si steel (Type A) and Cr-Mo-Ni steel (Type B) is lower than that in the cases of Cr-Mo steel (Type A) and Cr-Mo steel (Type B). In the cases of Cr-Mo-Si steel (A) and Cr-Mo-Ni steel (B), micro- and small-pitting area ratios are smaller and large-pitting life is longer than those in the cases of Cr-Mo steel(A) and Cr-Mo steel(B) under the same carburizing treatment method and high-load conditions. Furthermore, the relationship between the softening behavior of surface hardness on the heating pattern and the surface fatigue on the rolling-sliding contact of the developed alloy steels was clarified.

  16. Prix du pétrole : tendances à long terme et enjeux pour les biocarburants

    Directory of Open Access Journals (Sweden)

    Maisonnier Guy

    2013-09-01

    Full Text Available L’identification des grandes tendances et des paramètres critiques de l’évolution du prix du pétrole brut et des carburants est un des éléments avec la question du changement climatique pour définir des politiques publiques en matière de développement de filières de carburants alternatifs dans les transports. Le travail présenté ici essaie de proposer une grille d’analyse dans ce sens à la fois sur l’appréciation du marché à court terme (part des phénomènes géopolitiques et sur les scénarios possibles de long terme. Les notions de prix plancher (basé sur le coût marginal de production et de prix plafond (coût de solutions alternatives ou de substitution sont explicitées comme éléments définissant la fenêtre de variation des prix du pétrole brut sur un marché international. Des scénarios sur les changements possibles de l’offre (par exemple sur les bruts non conventionnels et de la demande (sous contrainte CO2 sont présentés pour évaluer cette fourchette possible : de 80 à 160 $/b en dollar constant. Les scénarios des prix des carburants et particulièrement celui du gazole sont ensuite déduits de cette analyse, à partir desquels sont positionnés les prix des biocarburants (ici issus des huiles végétales et donc les enjeux de leur compétitivité économique hors mécanismes d’incitation.

  17. Biocarburants : la Commission propose d’encourager leur utilisation

    Directory of Open Access Journals (Sweden)

    Vermeersch Georges

    2002-01-01

    Full Text Available Depuis longtemps, la Commission, le Parlement et le Conseil encouragent le développement des sources d’énergie renouvelables, et plus particulièrement des biocarburants. Cela s’est traduit, entre autres, par la publication en novembre 2000 d’un livre vert intitulé « Vers une stratégie européenne de sécurité d’approvisionnement énergétique », qui fixe comme objectif, d’ici 2020, le remplacement de 20% des carburants classiques par des carburants de substitution pour le transport routier. Plus récemment, en juin 2001, au sommet de Göteborg, a été souligné le rôle important des biocarburants dans la lutte contre le changement climatique et le développement des énergies propres. Ces encouragements restaient au niveau de la déclaration d’intention faute de moyens administratifs et fiscaux pour bâtir une véritable stratégie. Depuis le 7 novembre 2001, les choses semblent évoluer : en effet, à cette date, le collège des Commissaires a adopté une communication sur les carburants de substitution pour les transports routiers et une série de mesures visant à promouvoir l’utilisation des biocarburants. De plus - et c’est ce qui est fondamental - cette communication était assortie de deux propositions de directives, l’une visant à promouvoir l’utilisation des biocarburants dans les transports, l’autre concernant la possibilité d’appliquer un taux d’accises réduit sur certaines huiles minérales qui contiennent des biocarburants et sur les biocarburants.

  18. Novel bifunctional catalysts based on crystalline multi-oxide matrices containing iron ions for CO2 hydrogenation to liquid fuels and chemicals.

    Science.gov (United States)

    Utsis, N; Vidruk-Nehemya, R; Landau, M V; Herskowitz, M

    2016-07-04

    Seven solid mono-, bi- and tri-metallic oxide matrices where Fe(2+,3+) ions are distributed in different chemical/spatial environments were synthesized and characterized by XRD, N2-adsorption and EDAX methods. After basification with potassium, all matrices were activated by carburization or reduction-carburization under conditions selected based on the TPC/TPR spectra, tailoring the carburization extent of iron. The performances of the activated Fe-based catalysts with respect to CO2 conversion and C5+ selectivity were measured in a fixed-bed reactor under standard conditions in transient and continuous operation modes in units containing one or three reactors in series with water separations between the reactors. The catalysts were characterized by XRD, N2-adsorption, HRTEM-EELS and XPS before and after steady-state operation in the reactors. It was found that the rate of CO2 conversion is not limited by thermodynamic equilibrium but is strongly restricted by water inhibition and it depends on the nature of the Fe-oxide precursor. The ratio between the FTS and RWGS rates, which determines the C5+ hydrocarbons productivity, is strongly affected by the nature of the Fe-oxide matrix. The catalysts derived from the Fe-Al-O spinel and Fe-Ba-hexaaluminate precursors displayed the best balance of the two functions RFTS/RRWGS = 0.77-0.78. They were followed by magnetite, CuFe-delafossite, K-ferrite, Fe-La-hexaaluminate and LaFe-perovskite with a gradual lowering of RFTS/RRWGS from 0.60 to 0.15 and a gradual decrease in the C5+ productivity. The active sites that enhance the RWGS reaction are located on the surface of the Fe-oxide phases, while the FTS and methanation reactions occur on the surface of the Fe-carbide phases.

  19. Etude de la microstructure d'un acier 316 titane apres vieillissement et apres irradiation aux neutrons

    Science.gov (United States)

    Brun, G.; Le Naour, J.; Vouillon, M.

    1981-10-01

    La précipitation qui se produit lors de vieillissements de longue durée entre 450 et 700°C dans un acier 316 Ti soit hypertrempé soit écroui, a été étudiée en couplant les techniques de microscopic électronique et de microanalyse X. Pour les cas expérimentaux étudiés, les résultats obtenus montrent que la composition des carbures M 23C 6 et des phases σ, Laves et χ est peu sensible aux conditions de vieillissement et dépend également peu de l'état structural initial. Leur teneur en éléments principaux de l'alliage est d'ailleurs voisine de celle des phases précipitées dans l'acier non stabilisé. Excepté les carbures de type M 6C, toutes ces phases ont une teneur en nickel inférieure à celle de la matrice. Les premiers rérultats obtenus sur des matériaux irradiés aux neutrons montrent que la précipitation sous flux est différente de celle qui se produit dans l'acier vieilli. Les phases γ' et G ainsi que les carbures riches en nickel ont été observés. L'attention a été attirée sur le fait qu'il n'y a pas de corrélation simple entre la vitesse de gonflement et la teneuer résiduelle en nickel de la matrice.

  20. An alternative method of gas boriding applied to the formation of borocarburized layer

    Energy Technology Data Exchange (ETDEWEB)

    Kulka, M., E-mail: michal.kulka@put.poznan.pl; Makuch, N.; Pertek, A.; Piasecki, A.

    2012-10-15

    The borocarburized layers were produced by tandem diffusion processes: carburizing followed by boriding. An alternative method of gas boriding was proposed. Two-stage gas boronizing in N{sub 2}-H{sub 2}-BCl{sub 3} atmosphere was applied to the formation of iron borides on a carburized substrate. This process consisted in two stages, which were alternately repeated: saturation by boron and diffusion annealing. The microstructure and microhardness of produced layer were compared to those-obtained in case of continuous gas boriding in H{sub 2}-BCl{sub 3} atmosphere, earlier used. The first objective of two-stage boronizing, consisting in acceleration of boron diffusion, has been efficiently implemented. Despite the lower temperature and shorter duration of boronizing, about 1.5 times larger iron borides' zone has been formed on carburized steel. Second objective, the absolute elimination of brittle FeB phase, has failed. However, the amount of FeB phase has been considerably limited. Longer diffusion annealing should provide the boride layer with single-phase microstructure, without FeB phase. - Highlights: Black-Right-Pointing-Pointer Alternative method of gas boriding in H{sub 2}-N{sub 2}-BCl{sub 3} atmosphere was proposed. Black-Right-Pointing-Pointer The process consisted in two stages: saturation by boron and diffusion annealing. Black-Right-Pointing-Pointer These stages of short duration were alternately repeated. Black-Right-Pointing-Pointer The acceleration of boron diffusion was efficiently implemented. Black-Right-Pointing-Pointer The amount of FeB phase in the boride zone was limited.

  1. Effect of low temperature plasma hardening treatment on microstructure and properties of AISI 420 stainless steel%低温离子硬化处理对 AISI 420不锈钢组织与性能的影响

    Institute of Scientific and Technical Information of China (English)

    杜威; 赵程

    2014-01-01

    研究了低温离子渗氮、离子氮碳共渗和离子渗碳硬化处理对AISI 420马氏体不锈钢的显微组织、表面硬度、耐蚀性、耐磨性的影响。结果表明,离子渗氮、氮碳共渗和离子渗碳处理都可提高马氏体不锈钢的表面硬度;经不同工艺处理后的试样,除500℃×4 h渗氮工艺外,其他不锈钢试样表面的耐蚀性均未出现明显降低,当渗氮温度过高(500℃)时,由于CrN的析出使得渗氮层的耐蚀性显著下降;磨损试验的结果表明,离子渗碳处理后硬化层的耐磨性最佳。%Effect of low temperature plasma nitriding , nitrocarburizing and carburizing on microstructure , surface hardness , corrosion resistance and wear resistance of AISI 420 martensitic stainless steel was investigated . The results show that plasma nitriding , nitrocarburizing and carburizing process can increase the surface hardness .There is no significantly decrease to the corrosion resistance on the surface of Stainless steel treated by different treatment processes except of plasma nitriding at 500℃for 4 h.If the nitriding temperature is higher than 500℃, the corrosion resistance will significantly decline due to the precipitation of CrN .The wear results show that hardened layer of plasma carburizing sample has the best wear resistance .

  2. Alloys for 1000 degree C service in the Next Generation Nuclear Plant NERI 05-0191

    Energy Technology Data Exchange (ETDEWEB)

    Gary S. Was; J.W. Jones; T. Pollock

    2009-01-15

    The objective of the proposed research is to define strategies for the improvement of alloys for structural components, such as the intermediate heat exchanger and primary-to-secondary piping, for service at 1000 degree C in the He environment of the NGNP. Specifically, we will investigate the oxidation/carburization behavior and microstructure stability and how these processes affect creep. While generating this data, the project will also develop a fundamental understanding of how impurities in the He environment affect these degradation processes and how this understanding can be used to develop more useful life prediction methodologies.

  3. Biodiesel : la réglementation européenne et le débat sur son évolution

    Directory of Open Access Journals (Sweden)

    Dusser Philippe

    2013-09-01

    Full Text Available La réglementation communautaire sur les biocarburants a été mise en place à partir de 2003 pour répondre à un triple objectif : réduction des émissions de gaz à effet de serre, réduction de la dépendance énergétique, et soutien à la production agricole dans un contexte où 10 % des terres étaient obligatoirement gelées. Cette réglementation a été renforcée en 2009 dans le cadre du « paquet énergie » par l’introduction par la directive energie renouvelable d’un objectif obligatoire d’incorporation de 10 % d’énergie renouvelable dans les carburants à l’horizon 2020. Cette législation est complétée par une directive qualité des carburants qui impose une réduction de 6 % d’ici 2020 de l’empreinte carbone des carburants. La forte diésélisation du parc de véhicule en Europe a conduit à une rapide progression de la consommation de biodiesel (11 millions de tonnes dont 9 produites dans l’UE. L’huile de colza est la principale matière première du biodiesel. L’augmentation de la production de colza a permis de répondre à cette demande, tout en fournissant un coproduit protéique permettant de réduire significativement le déficit en protéines européen. Le débat sur l’impact du CASI (changement indirect d’affectation des sols des biocarburants, ainsi que celui sur l’équilibre alimentaire, a conduit la Commission européenne, 3 ans après avoir défini sa politique, à proposer de plafonner les carburants issus des cultures (1ere génération à 5 % et à introduire des « facteurs CASI » dans l’évaluation des effets de réduction des gaz à effets de serre. Cette proposition qui pourrait fortement remettre en cause le développement du biodiesel...et de la culture de colza fait à la date de rédaction de cet article (juillet 2013 l’objet de difficiles négociations à Bruxelles, dont l’issue est difficile à prédire.

  4. New microalloyed steel applications for the automotive sector

    Energy Technology Data Exchange (ETDEWEB)

    Matlock, D.K.; Krauss, G.; Speer, J.G. [Advanced Steel Processing and Products Research Center, Colorado School of Mines, Golden, CO (United States)

    2005-07-01

    Developments related to the use of microalloy additions, primarily of Ti, Nb, and V, and controlled processing are reviewed to illustrate how steels with tailored microstructures and properties are produced from either bar or sheet steels for new automotive components. Microalloying additions are shown to control the necessary strengthening mechanisms to produce high strength materials with the desired toughness or formability for a specific application. Selected examples of direct cooled forging steels, microalloyed carburizing steels, and advanced high strength sheet (AHSS) steels are discussed. (orig.)

  5. Mezclas etanol-gasolina como combustible de motores de encendido por chispa

    OpenAIRE

    2010-01-01

    In the Agricultural Mechanics Shop at Texas A&I University in Kingsville (TX), six ethanolgasoline blends (0, 20, 40, 60, 80 and 100% ethanol) were used to operated a six-cylinder engine at different operating conditions of air-fuel ratio, timing, load and speed. A main jet the carburator was used for each fuel to obtaining its stoichiometric air-fuel ratio. The main jet diameter was enlarged 1262 times from gasoline to ethanol. To select the optimun timing, timing was varied from Oto 26°...

  6. Effect of carbon on the oxidation of zirconium; Influence du carbone sur l'oxygenation du zirconium a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Chauvin, G.; Boudouresques, B.; Coriou, H.; Hure, J. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1959-07-01

    The study of specimens contaminated by different amounts of carbon shows a deleterious effect of this element in the resistance of zirconium to high temperature oxidation (700 to 900 deg. C). We drew the following results: a) the white spots or 'pimples' observed by numerous authors seem to be caused by the oxidation of precipitated carbides. We suggest a mechanism of formation and growth of these pimples; b) for a certain carbon content, the resistance to oxidation is increased by an uniform dispersion of the carbide phase and decreased, for instance, by extrusion textures. In this case, for the more marked textures, the more oriented corrosion was observed; c) by burning of the carbide phase it can result a second reaction increasing the corrosion rate; d) thin zirconium foils undergoes dimensional changes when scaling in oxygen. This unusual feature is also subordinated to carbon content and specially to the carbide phase dispersion. (author) [French] L'etude d'echantillons differemment contamines par le carbone nous a permis de mettre en evidence l'action particulierement nocive de cet element sur la resistance du zirconium a la corrosion par l'oxygene a haute temperature (700 a 900 deg. C). Nous avons pu degager les resultats essentiels suivants: a) l'origine des pustules d'oxyde blanc signalees par de nombreux auteurs doit etre recherchee dans l'oxydation des carbures precipites. Nous suggerons un mecanisme de formation et de croissance de ces pustules, b) la tenue du metal est d'autant meilleure que, pour une meme teneur en carbone, la phase 'carbure' est plus uniformement dispersee. En consequence, si la dispersion est mauvaise, on observe selon l'axe des textures de filage, par exemple, une corrosion preferentielle d'autant plus accentuee que les textures sont plus marquees, c) la combustion de la phase 'carbure' peut engendrer une reaction secondaire susceptible d

  7. Carbon Formation and Metal Dusting in Hot-Gas Cleanup Systems of Coal Gasifiers

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, Peter F.; Judkins, Roddie R.; DeVan, Jackson H.; Wright, Ian G.

    1995-12-31

    There are several possible materials/systems degradation modes that result from gasification environments with appreciable carbon activities. These processes, which are not necessarily mutually exclusive, include carbon deposition, carburization, metal dusting, and CO disintegration of refractories. Carbon formation on solid surfaces occurs by deposition from gases in which the carbon activity (a sub C) exceeds unity. The presence of a carbon layer CO can directly affect gasifier performance by restricting gas flow, particularly in the hot gas filter, creating debris (that may be deposited elsewhere in the system or that may cause erosive damage of downstream components), and/or changing the catalytic activity of surfaces.

  8. 密封箱式多用炉的现状%Application Circumstances of Sealed Multi-purpose Furnace

    Institute of Scientific and Technical Information of China (English)

    吉泽升; 康国华; 赵密

    2001-01-01

    The sealed multi-purpose furnace is widespreadly used heat treatment furnace.The development circumstance of construction,material,carburizing technology and control system of sealed multi-purpose furnace is introduced in this paper.%密封箱式多用炉是当今热处理炉的一个发展趋势,本文介绍了密封箱式多用炉在材料、结构、渗碳和控制等方面的现状。

  9. Dosage direct des alcools dans les carburols par chromatographie en phase gazeuse Direct Gas Chromatographie Determination of Alcohols in Gasolines Blended by Oxygenated Compounds

    Directory of Open Access Journals (Sweden)

    Petroff N.

    2006-11-01

    Full Text Available Dans cette étude, on décrit une méthode de chromatographie en phase gazeuse utilisant une colonne remplie ; elle permet de doser, sans préfractionnement, les alcools jusqu'aux butanols dans les carburols (carburants additionnés de composés oxygénés. La phase stationnaire sélectionnée est le glycérol. This report describes a gas chromatographie method using a packed column. It allows the direct determination of alcohols up to butanols in gasolines blended with oxygenated compounds without prefractionation. Glycerol has been selected as stationary phase.

  10. Thermostability of Sm{sub 2}(FeGa){sub 17}C{ital {sub y}} prepared by gas-solid reaction (GSR)

    Energy Technology Data Exchange (ETDEWEB)

    Cao, L.; Handstein, A.; Gebel, B.; Schaefer, R.; Mueller, K. [Institute for Solid State and Materials Research Dresden, P.O. Box 270016, D-01171 Dresden (Germany)

    1997-04-01

    The gas-solid-reaction (GSR) was used to introduce interstitial carbon atoms into Sm{sub 2}Fe{ital {sub 17{minus}x}}Ga{ital {sub x}} compounds with {ital x=0}, 0.5, 1, and 2. For this process, powders made from homogenized ingots were annealed at 500{degree}C under methane for different times. The thermostability increases for small amounts of Ga and the investigation shows that Sm{sub 2}Fe{sub 16.5}Ga{sub 0.5}C{ital {sub y}} is stable up to 750{degree}C. In the case of Sm{sub 2}Fe{sub 15}Ga{sub 2}C{ital {sub y}} carburized for 6 h {ital (y=2.0)} and 18 h {ital (y=2.2)}, the x-ray diffraction patterns show the Th{sub 2}Zn{sub 17}-type structure only. After annealing at 800{degree}C for 20 min the 6 h carburized sample shows a small amount of {alpha}-Fe and other phases and there is a large Fe content after annealing at 850{degree}C. For an 18 h carburized sample, less Fe and no other phases have be seen after annealing at 800{degree}C, i.e., the material is nearly single phase. The result that longer carburization times stabilize the Th{sub 2}Zn{sub 17}-type structure could also be manifested by Kerr microscopy. A comparison with mechanically alloyed Sm{sub 2}Fe{sub 15}Ga{sub 2}C{sub 2} powders prepared with Sm excess shows that those are very stable up to 900{degree}C. The density of fine-grained Sm{sub 2}Fe{ital {sub 17{minus}x}}Ga{ital {sub x}}C{ital {sub y}} could be increased by hot pressing, but the degree of compaction and the phase purity very sensitively depend on the Ga content. {copyright} {ital 1997 American Institute of Physics.}

  11. Synthesis of Nanocrystalline α-Mo_2C from Peroxomolybdenum Compounds

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Introduction Considerable attentions have been focused on transition metal carbide because of their numerous valuable properties, particularly of excellent catalysis similar to noble metal[1]. There are many routes[2]to synthesize molybdenum carbide. Among them, the temperature programmed reduction of MoO3 using the mixture of hydrocarbon and hydrogen is the most promising procedure to prepare carbide catalyst. Traditionally, CH4/H2 and C2H6/H2 are the most widely used to be the carburizing resource. ...

  12. Formation of titanium carbide coating with micro-porous structure

    Science.gov (United States)

    Luo, Yong; Ge, Shirong; Jin, Zhongmin; Fisher, John

    2010-03-01

    Micro-porous titanium carbide coating was successfully synthesized in a vacuum gas carburizing furnace by using a sequential diffusion technology. The composition and structure of the as-synthesized TiC were examined by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and glow discharge mass spectrometry (GDMS), and scanning electron microscopy (SEM). All of the XRD, XPS and GDMS analysis results indicate that carbon atoms effectively diffused into the titanium alloys and formed a uniform acicular TiC coating with micro-porous structure.

  13. Metal-dusting resistance of uncoated and coated iron and nickel base materials against metal-dusting in heat treatment furnaces with carbonaceous atmospheres; Bestaendigkeit von unbeschichteten und beschichteten Eisen- und Nickelbasiswerkstoffen gegenueber Metal-Dusting in Aufkohlanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Kleingries, Mirko; Ackermann, Helen; Lucka, Klaus [OWI Oel-Waerme-Institut GmbH, Aachen (Germany); Hoja, Timo; Mehner, Andeas; Zoch, Hans-Werner [IWT, Stiftung Institut fuer Werkstofftechnik, Bremen (Germany); Altena, Herwig [AICHELIN Ges.m.b.H, Moedling (Austria)

    2010-03-15

    Metal-Dusting is a well-known corrosion problem that occurs in carburizing atmospheres in industrial thermal processing plants. In literature almost no quantitative data on the metal dusting resistance of typical alloys employed in industrial furnaces are available. Therefore, a series of experiments with uncoated and sol gel ZrO{sub 2} coated high temperature materials was conducted in order to quantify their metal dusting behaviour under conditions close to those in case hardening furnaces. The experimental results show a strong influence of the surface conditions on the alloys resistance and a noticeable enhancement of the resistance by sol gel coatings. (orig.)

  14. The factors affecting the recarburization process indicators

    Directory of Open Access Journals (Sweden)

    K. Janerka

    2011-07-01

    Full Text Available The article presents the factors affecting the carburizing rates obtained (rate and efficiency during the process of melting cast iron. The analysis includes the recarburizer type (anthracite, natural and synthetic graphite, petroleum coke and particle size. Further factors considered in work are the methods of recarburization (recarburizer introduction to a solid charge and on the surface of the metal bath and the parameters of the melt (temperature and chemical composition. The analysis was based on experiments performed, the calculation results of computer simulations and literature data.

  15. PECULIAR FEATURES OF ELECTROLYTIC-PLASMA HEATING DURING ELECTROCHEMICAL HEAT-TREATMENT OF STEEL

    Directory of Open Access Journals (Sweden)

    Yu. Alekseev

    2013-01-01

    Full Text Available Thermo-physical peculiar features of  anode electrolytic-plasma heating applied for heat and chemical heat-treatment have been investigated in the paper. The paper presents  results of the investigations pertaining  to influence of the operating voltage on current density, temperature and heating rate, heating power and  changes in heat portion passing to the anode. Peculiar features of layer formation which are hardened  by electrolytic-plasma carburizing  have been presented in the paper.

  16. Influence Of Heat Treatment On Duplex Stainless Steel To Study The Material Properties

    Directory of Open Access Journals (Sweden)

    Jithin M

    2015-02-01

    Full Text Available Abstract The various heat treatment processes are annealing normalizing hardening tempering spheroidising surface hardening flame and induction hardening nitriding cyaniding carbonitriding carburizing etc Heat treatment on duplex stainless steel is to improve ductility toughness strength hardness and to relieve internal stress developed in the material. Here basically the experiment of hardness test impact test wear test and compression is done to get idea about heat treated duplex stainless steel which has extensive uses in all industries and scientific research and development fields.

  17. FORMATION OF HIGHLY RESISTANT CARBIDE AND BORIDE COATINGS BY A TWO-STAGE DEPOSITION METHOD

    Directory of Open Access Journals (Sweden)

    W. I. Sawich

    2011-01-01

    Full Text Available A study was made of the aspects of forming highly resistant coatings in the surface zone of tool steels and solid carbide inserts by a two-stage method. at the first stage of the method, pure Ta or Nb coatings were electrodeposited on samples of tool steel and solid carbide insert in a molten salt bath containing Ta and Nb fluorides. at the second stage, the electrodeposited coating of Ta (Nb was subjected to carburizing or boriding to form carbide (TaC, NbC or boride (TaB, NbB cladding layers.

  18. Microwave synthesis of ultrafine and nanosized powders of tungsten oxide and carbide

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaenko, Irina; Kedin, Nikolay; Shveikin, Gennadii; Polyakov, Evgenii [Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Solid State Chemistry

    2014-03-15

    A new method of synthesis of nanosized and ultrafine tungsten oxide and carbide powders is offered, which combines carbon carrier supported classical liquid-phase precipitation and low-temperature microwave treatment. The full range of intermediate substances obtained during thermolysis, reduction and carburization of precursors to final products is presented. It is shown that cooling of ammonium tungstate solution to 4 C and the use of carbon carrier at the precipitation stage can increase the specific surface area from 20 to 100 m{sup 2} g{sup -1}. (orig.)

  19. Multiscale architectured materials with composition and grain size gradients manufactured using high-pressure torsion.

    Science.gov (United States)

    Kang, Ji Yun; Kim, Jung Gi; Park, Hyo Wook; Kim, Hyoung Seop

    2016-05-27

    The concept of multiscale architectured materials is established using composition and grain size gradients. Composition-gradient nanostructured materials are produced from coarse grained interstitial free steels via carburization and high-pressure torsion. Quantitative analyses of the dislocation density using X-ray diffraction and microstructural studies clearly demonstrate the gradients of the dislocation density and grain size. The mechanical properties of the gradient materials are compared with homogeneous nanostructured carbon steel without a composition gradient in an effort to investigate the gradient effect. Based on the above observations, the potential of multiscale architecturing to open a new material property is discussed.

  20. The electromagnetic force field, fluid flow field and temperature profiles in levitated metal droplets

    Science.gov (United States)

    El-Kaddah, N.; Szekely, J.

    1982-01-01

    A mathematical representation was developed for the electromagnetic force field, the flow field, the temperature field (and for transport controlled kinetics), in a levitation melted metal droplet. The technique of mutual inductances was employed for the calculation of the electromagnetic force field, while the turbulent Navier - Stokes equations and the turbulent convective transport equations were used to represent the fluid flow field, the temperature field and the concentration field. The governing differential equations, written in spherical coordinates, were solved numerically. The computed results were in good agreement with measurements, regarding the lifting force, and the average temperature of the specimen and carburization rates, which were transport controlled.

  1. Estudio de la reoxidación y carburización de pelets reducidos de mineral de hierro

    Directory of Open Access Journals (Sweden)

    Lemus R., J.

    1998-12-01

    Full Text Available The influence of carburization on the reoxidation of commercial iron ore pellets was studied. The pellets were H2-reduced up to 88 % and then carburized in H2/CO/CO2 gas mixture, for 0, 12, 18, 25 and 32 min, at 700, 800, 900 and 1000°C. After the reduction-carburization process, the pellets were reoxidized at 250, 300, 350 and 400°C. It was found out that the higher reduction temperature, the lower was the reoxidation degree. This effect was stronger at the reoxidation temperatures of 250 and 300°C. The presence of iron carbide (Fe3C was more notorious when the reduction was carried out at 700 and 800°C, and the carburization time was increased. Finally, it was observed that the higher the reoxidation temperature, the higher was the reoxidation degree.

    Se estudió la influencia de la carburización en la reoxidación de pelets de mineral de hierro de grado comercial. Los pelets fueron reducidos en hidrógeno hasta un 88 % y carburizados en una mezcla de gas H2-CO-CO2, por 0, 12, 18, 25 y 32 min a 700, 800, 900 y 1000°C. Después del proceso de reducción-carburización, los pelets se reoxidaron a 250, 300, 350 y 400°C. Se encontró que el grado de reoxidación disminuye con el incremento de la temperatura de reducción. Este efecto es más marcado a las temperaturas de reoxidación de 250°C y 300°C. La presencia de carburo de hierro (Fe3C fue más clara al incrementarse el tiempo de carburización cuando la reducción se llevó a cabo a 700 y 800°C. Finalmente, se observó que el grado de reoxidación es mayor a medida que se incrementa la temperatura de reoxidación .

  2. An introduction to surface alloying of metals

    CERN Document Server

    Hosmani, Santosh S; Goyal, Rajendra Kumar

    2014-01-01

    An Introduction to Surface Alloying of Metals aims to serve as a primer to the basic aspects of surface alloying of metals. The book serves to elucidate fundamentals of surface modification and their engineering applications. The book starts with basics of surface alloying and goes on to cover key surface alloying methods, such as carburizing, nitriding, chromizing, duplex treatment, and the characterization of surface layers. The book will prove useful to students at both the undergraduate and graduate levels, as also to researchers and practitioners looking for a quick introduction to surface alloying.

  3. Des changements concevables pour le secteur des transports dans l'objectif "Facteur 4"

    OpenAIRE

    Raux, Charles

    2007-01-01

    Au niveau mondial, les transports consomment 20% de l'énergie, dont 80% dans les transports routiers et 10% dans les transports aériens, et 95% de cette énergie est à base de pétrole. Le secteur des transports est l'un des principaux émetteurs de gaz à effet de serre dans la plupart des pays, et notamment du CO2 issu de la combustion des carburants fossiles. Pour que les transports contribuent significativement à l'objectif du « Facteur 4 » en 2050, trois pistes différentes mais complémentair...

  4. Kinetics of Hydrocarbon formation in a-C:H film deposition plasmas

    Energy Technology Data Exchange (ETDEWEB)

    De la Cal, E.; Tabares, F.L.

    1993-07-01

    The formation of C{sub 2} and C{sub 3} hydrocarbons during the PACVD of a-C-H films from admixtures of methane with H{sub 2} and He has been investigated by mass espectrometry under several deposition condition. The time evolution of the observed species indicates that the formation mechanism of ethylene and acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene are sensitive to the conditions of the wall during the growing of the carburized metal. (Author)

  5. Bioraffinerie and Knowledge Based BioEconomy

    OpenAIRE

    2016-01-01

    La question de la transition vers un paradigme de l′usage des ressources renouvelables se traduit par des efforts particuliers de mobilisation de la recherche ; cette mobilisation se déploie dans des domaines divers (énergie solaire, éolienne, substituts du carbone fossile par du carbone renouvelable en énergie, production de carburants liquides et chimie). La volonté de substitution liée à cet effort de production de carbone renouvelable conduit à s′intéresser au domaine spécifique de la bio...

  6. Austempered ductile iron process development

    Science.gov (United States)

    Gupta, C. D.; Keough, J. R.; Pramstaller, D. M.

    1986-11-01

    Pressure from imports and material substitution has severly affected demand for domestic iron industry products. It is estimated that the potential market for Austempered Ductile Iron (ADI) is as large as the market for carburized and/or through hardened forgings. The primary interest in ADI is generated by the economics of process. Improved machinability and reduced processing costs as well as interesting physical properties has created an enormous interest in all metalworking industries towards ADI. The development of gas-fired austempering processes and resoluton of technical and economic uncertainities concerning the process will help improve the outlook for iron founderies.

  7. Méthode sous-optimale de commande des transistors Grand Gap dans un convertisseur DC/DC réversible isolé

    OpenAIRE

    Cougo, Bernardo; Schneider, Henri

    2014-01-01

    National audience; De nombreux travaux cherchent à améliorer les performances des convertisseurs d'énergie électrique embarqués à bord des futurs avions. Les transistors à base de carbure de silicium (SiC) et nitrure de gallium (GaN), qui peuvent commuter plus rapidement que leurs homologues à base de silicium, offrent, dans ce cadre, des perspectives intéressantes. Cet article présente l'étude d'un convertisseur DC/DC Bidirectionnel Isolé (appelé Dual Active Bridge, DAB) qui fera l'interface...

  8. Corrosion Problems in the Canadian Maritime Forces

    Science.gov (United States)

    1984-12-01

    des tubes d6surchauf fours, des collecteurs do carburant des turbines it gaz et des chaudi~res auxiliairos et do r~cup~ration des gaz perdus. La...corrosion. TABLE OF CONTENTS Paxe Number Abstract i 1. Introduction 2. Machinery 2 2.1 Solar Saturn Fuel Manifold 2 2.2 Desuperheater Tubes 2 2.3 DDH 280’s...them. The case histories are divided into three categories: machinery, seawater systems and general. 2. MACHINERY 2.1 Solar Saturn Fuel Manifold Solar

  9. Environmental transmission electron microscopy investigations of Pt-Fe2O3 nanoparticles for nucleating carbon nanotubes

    DEFF Research Database (Denmark)

    He, Maoshuai; Jin, Hua; Zhang, Lili

    2016-01-01

    Elucidating the evolution of bimetallic catalyst for nucleating carbon nanotube has been challenging. In this work, acorn-like Pt-Fe2O3 nanoparticles are developed for the growth of single-walled carbon nanotubes (SWCNTs) by chemical vapor deposition. Using in situ environmental transmission...... electron microscopy, restructuring of the acorn-like Pt-Fe2O3 nanoparticles at reaction conditions is investigated. Upon heating to reaction temperature, ε-Fe2O3 is converted to β-Fe2O3, which can be subsequently reduced to metallic Fe once introducing CO. As Pt promotes the carburization of Fe, part...

  10. Mechanisms of metal dusting corrosion

    DEFF Research Database (Denmark)

    Hummelshøj, Thomas Strabo

    In this thesis the early stages of metal dusting corrosion is addressed; the development of carbon expanded austenite, C, and the decomposition hereof into carbides. Later stages of metal dusting corrosion are explored by a systematic study of stainless steel foils exposed to metal dusting...... influence of oxygen and carbon on the metal dusting corrosion is explored. The results indicate that exposure to metal dusting conditions have a detrimental effect on the resistance against oxidation and, conversely, that exposure to oxidation has a detrimental effect on the resistance towards metal dusting....... Consequently, a combination of carburizing and oxidizing conditions has a strong mutual catalyzing effect on the metal dusting corrosion....

  11. Physical and Numerical Analysis of Extrusion Process for Production of Bimetallic Tubes

    Energy Technology Data Exchange (ETDEWEB)

    Misiolek, W.Z.; Sikka, V.K.

    2006-08-10

    Bimetallic tubes are used for very specific applications where one of the two metals provides strength and the other provides specific properties such as aqueous corrosion and carburization, coking resistance, and special electrical and thermal properties. Bimetallic tubes have application in pulp and paper industry for heat-recovery boilers, in the chemical industry for ethylene production, and in the petrochemical industry for deep oil well explorations. Although bimetallic tubes have major applications in energy-intensive industry, they often are not used because of their cost and manufacturing sources in the United States. This project was intended to address both of these issues.

  12. Bio-energies. The domestic use of wood fuel: the weight of discretion. The urban and industrial wood heating, a growth value. Biomass - electricity - heat, towards a new concept. Bio-gas, a fermenting stake. Bio-components for fuels, foresight and quality. Biomolecules: towards a chemistry of substitution. Wood materials: a concentrate of environment; Les bioenergies. L'usage domestique du bois energie: le poids de la discretion. Le chauffage urbain et industriel au bois, une valeur de croissance. Biomasse - electricite - chaleur, vers un nouveau concept. Le biogaz, un enjeu qui fermente. Biocomposants pour carburants, prevoyance et qualite. Les biomolecules: vers une chimie de substitution. Le bois materiau: un concentre d'environnement

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    This dossier presents a status of todays situation of the use of bio-energies in France and of its perspectives of development at the year 2006 vista. Seven aspects of bio-energies are considered: wood fuel, district and industrial heating, biomass production and gasification processes, biogas (methane) production from municipal waste tips, bio-fuels and bio-additives (bio-ethanol, ETBE, colza derived oils, vegetal oil methyl esters), bio-molecules production and valorization as substitutes to petroleum products (lubricants, wetting agents, solvents, polymers, coatings), development of wood materials (environmental advantages: CO{sub 2} immobilization, lower energy needs during fabrication, possible energy valorization at end life). (J.S.)

  13. Application of Empirical Electron Theory of Solids and Molecules to Composition Design of Multi-Component Medium-Low-Alloy Steels

    Institute of Scientific and Technical Information of China (English)

    SHI Juyan; XIE Guisheng

    2012-01-01

    For austenitic octahedral segregation structure units,their pure mathematics statistic distributive probability is calculated by the empirical electron theory (EET) of solids and molecules and K-B formula.The practical distributive probability can be obtained only if the statistic distribution of austenitic octahedral segregation structure units and the interaction of the alloying elements in steel are considered.Based on 8 groups of experimental data of original steels,three empirical formulas revealing relationships between material macromechanics factor (Sm) and tensile strength (σb),or impact energy (Aκ),or hardness (HRC) of multi-component medium-low-alloy steels were established,respectively.Through the three empirical formulas,new supersaturated carburizing steel has been successfully designed and developed.The other 2 groups of the original experimental steels are used as the standard steel for testing the percentage error of the new steel.The results show that the calculated values are well consistent with those of measured ones and the new supersaturated carburized steel can meet the requirements of the die assembly of cold-drawn seamless stainless steel tube of Taiyuan Iron & Steel (Group) Company LTD.

  14. FY 1998 annual report on the development of plasma-aided surface treatment processes by in-situ controlling (second year); 1997 nendo in-situ seigyo ni yoru plasma riyo hyohi shori process no kaihatsu seika hokokusho (dai 2 nendo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    This R and D project is aimed at stable production of high-quality, important machine members, which are difficult to sufficiently achieve the required properties by a single material, by carburization while minimizing use of expensive alloy metals, where high-temperature carburizing time is reduced by a plasma-aided system to save energy, and, at the same time, the conventional oil-hardening system is replaced by a He gas cooling/recycling system to solve the environmental problems involved in the former. The exhaust gases released from the plasma-aided system are adequately treated to prevent the problems caused thereby. The conditions of the plasma itself and treated surfaces are sensed in-situ, and the data are fed back to the process controlling system, to keep the treated object stable and high in quality, while minimizing energy consumption. The FY 1998 efforts were directed to studies on methods for sensing the plasma and treated surfaces, and specifications of a mini-plant for the demonstration tests, and to collection of characteristic data for development of some new products to be produced. (NEDO)

  15. Use of High Magnetic Fields to Improve Material Properties for Hydraulics, Automotive and Truck Components

    Energy Technology Data Exchange (ETDEWEB)

    Ludtka, Gerard Michael [ORNL; Ludtka, Gail Mackiewicz- [ORNL; Wilgen, John B [ORNL; Kisner, Roger A [ORNL; Ahmad, Aquil [Eaton Corporation

    2010-08-01

    In this CRADA, research and development activities were successfully conducted on magnetic processing effects for the purpose of manipulating microstructure and the application specific performance of three alloys provided by Eaton (alloys provided were: carburized steel, plain low carbon steel and medium carbon spring steel). Three specific industrial/commercial application areas were considered where HMFP can be used to provide significant energy savings and improve materials performance include using HMFP to: 1.) Produce higher material strengths enabling higher torque bearing capability for drive shafts and other motor components; 2.) Increase the magnetic response in an iron-based material, thereby improving its magnetic permeability resulting in improved magnetic coupling and power density, and 3.) Improve wear resistance. The very promising results achieved in this endeavor include: 1.) a significant increase in tensile strength and a major reduction in volume percent retained austenite for the carburized alloy, and 2.) a substantial improvement in magnetic perm respect to a no-field processed sample (which also represents a significant improvement over the nominal conventional automotive condition of no heat treatment). The successful completion of these activities has resulted in the current 3-year CRADA No. NFE-09-02522 Prototyping Energy Efficient ThermoMagnetic and Induction Hardening for Heat Treat and Net Shape Forming Applications .

  16. Rolling Bearing Steels - A Technical and Historical Perspective

    Science.gov (United States)

    Zaretsky, Erwin V.

    2012-01-01

    Starting about 1920 it becomes easier to track the growth of bearing materials technology. Until 1955, with few exceptions, comparatively little progress was made in this area. AISI 52100 and some carburizing grades (AISI 4320, AISI 9310) were adequate for most applications. The catalyst to quantum advances in high-performance rolling-element bearing steels was the advent of the aircraft gas turbine engine. With improved bearing manufacturing and steel processing together with advanced lubrication technology, the potential improvements in bearing life can be as much as 80 times that attainable in the late 1950s or as much as 400 times that attainable in 1940. This paper summarizes the chemical, metallurgical and physical aspects of bearing steels and their effect on rolling bearing life and reliability. The single most important variable that has significantly increased bearing life and reliability is vacuum processing of bearing steel. Differences between through hardened, case carburized and corrosion resistant steels are discussed. The interrelation of alloy elements and carbides and their effect on bearing life are presented. An equation relating bearing life, steel hardness and temperature is given. Life factors for various steels are suggested and discussed. A relation between compressive residual stress and bearing life is presented. The effects of retained austenite and grain size are discussed.

  17. Field test of thermoelectric generating system at Komatsu plant

    Energy Technology Data Exchange (ETDEWEB)

    Kaibe, Hiromasa T.; Fujimoto, Sinichi; Mizukami, Hiroyuki; Morimoto, Shigeo [Komatsu Ltd., Kanagawa (Japan)

    2011-07-01

    At the end of October 2009, Komatsu Ltd. started a field test of the thermoelectric generation (TEG) system at a carburizing facility of Awazu plant. Residual carburizing gas based on such as CO, N and H{sub 2} is burned resulting that 20-30 kW range of flame constantly heats up the hot side of TEG. 16 of the Bi-Te thermo-modules, which were separated into 4 groups, were employed, each of which has a size of 50 by 50 by 4.2 mm{sup 3} and can generate better than 25 W under the circumstance of 280 C and 30 C of hot side and cold side temperature, respectively. Each module has a single booster-type DC/DC converter controlled by one chip computer and Maximum Power point Tracking (MPPT) was well facilitated to search for the maximum output power depending on the hot and cold side temperature. The electric output power from the four modules is summed up to charge a single lead storage battery (GS Yuasa Corp. 12V-65Ah) and then through a DC/AC inverter electricity goes to fluorescent light tubes inside the factory. Typically from 4 groups 200 W can be generated and 170 W is delivered to the batteries. (orig.)

  18. Kinetics of the formation of metal binder gradient in WC-Co by carbon diffusion induced liquid migration

    Energy Technology Data Exchange (ETDEWEB)

    Guo Jun [Department of Metallurgical Engineering, University of Utah, 135 S. 1460 E. Room 412, Salt Lake City, UT 84112 (United States); Fang, Zhigang Zak, E-mail: zak.fang@utah.edu [Department of Metallurgical Engineering, University of Utah, 135 S. 1460 E. Room 412, Salt Lake City, UT 84112 (United States); Fan Peng; Wang Xu [Department of Metallurgical Engineering, University of Utah, 135 S. 1460 E. Room 412, Salt Lake City, UT 84112 (United States)

    2011-06-15

    Cemented tungsten carbide (WC-Co) with a cobalt content gradient from the surface to the bulk of a sintered piece is an example of a functionally graded material, the mechanical properties of which are optimized by the unique gradient microstructure, giving rise to superior combinations of wear resistance vs. fracture toughness. A process for creating such cobalt gradients in WC-Co was developed recently based on heat treatments of fully sintered WC-Co materials in carburizing atmospheres. A study of the kinetics of the process is necessary to fully understand the mechanisms of the process in order to achieve desired or designed gradients. In this paper, a series of carburizing experiments were conducted to examine the effects of key process parameters including temperature, composition of the atmosphere, and time on the overall kinetics of the process. A kinetic model was established to predict the thickness of the gradient as a function of these process variables, enabling the design of functionally graded WC-Co through controlling atmosphere and time.

  19. Effects of magnetic field intensity on carbon diffusion coefficient in pure iron in γ-Fe temperature region

    Science.gov (United States)

    Wu, Yan; Duan, Guosheng; Zhao, Xiang

    2015-03-01

    Effects of magnetic field intensity on carbon diffusion coefficient in pure iron in the γ-Fe temperature region were investigated using carburizing technology. The carbon penetration profiles from the iron surface to interior were measured by field emission electron probe microanalyzer. The carbon diffusion coefficient in pure iron carburized with different magnetic field intensities was calculated according to the Fick's second law. It was found that the magnetic field intensity could obviously affect the carbon diffusion coefficient in pure iron in the γ-Fe temperature region, and the carbon diffusion coefficient decreased obviously with the enhancement of magnetic field intensity, when the magnetic field intensity was higher than 1 T, the carbon diffusion coefficient in field annealed specimen was less than half of that of the nonfield annealed specimen, further enhancing the magnetic field intensity, the carbon diffusion coefficient basically remains unchanged. The stiffening of lattice due to field-induced magnetic ordering was responsible for an increase in activation barrier for jumping carbon atoms. The greater the magnetic field intensity, the stronger the inhibiting effect of magnetic field on carbon diffusion.

  20. Preparation of non-spherical hollow carbon nanocapsules from nickel nanoprecursors

    Science.gov (United States)

    Chiang, Ray-Tung; Chiang, Ray-Kuang; Shieu, Fuh-Sheng

    2012-08-01

    Hollow carbon nanocapsules (NCs) are prepared from nickel nanoplate precursors through carburizing, decomposition, and leaching steps. The carburizing step was carried out by heating the nickel nanoplates in oleylamine at 250 °C for 4 h. Decomposition was then performed in a nitrogen atmosphere at 530 °C for 3 min. Characterization of the resulting product of the first two steps shows the intermediates to be Ni3C/Ni-C alloy and Ni/C core-shell nanostructures. Hollow carbon NCs are recovered from the products by leaching the Ni/C core-shell nanostructures in concentrated nitric acid. The NCs are found to have a high specific surface area (1081 m2 g-1) and a mesoporous structure (i.e., a pore volume of 2.81 cm3/g and a narrow pore size distribution of 2.9-3.4 nm). In addition, it is found that the hollow carbon NCs retained the same morphology as the original nickel precursors; demonstrating the robustness of the nickel templates and the ability of the carbon shells to maintain a non-spherical shape.

  1. They Came From the Deep in the Supernova: The Origin of TiC and Metal Subgrains in Presolar Graphite Grains

    CERN Document Server

    Lodders, K

    2006-01-01

    A new formation scenario for TiC and Fe,Ni-metal inclusions in presolar graphite grains of supernova origin is described. The mineralogy and chemistry require condensation of (Fe,Ni)-titanides from Fe, Ni, and Ti-rich gaseous ejecta, subsequent carburization to make TiC and metal, and encapsulation into graphite. Titanides only condense if Si is depleted relative to heavier mass elements, which requires alpha-rich freeze-out and a deep mass-cut for the supernova ejecta. This Si-poor core material must remain unmixed with other supernova zones until the titanides condensed. This can be accomplished by transport of core ejecta in bipolar jets through the major expanding supernova zone ejecta. If the jets stall in regions dominated by C-rich ejecta such as C-He zone where graphite condenses, thermochemically favored in situ carburization of the titanides - either before or during encapsulation into condensing graphite - leads to a TiC and metal composite. This scenario agrees with theoretical models and observat...

  2. Surface Modification of Commercially Pure Titanium by Plasma Nitrocarburizing at Different Temperatures and Duration Process

    Directory of Open Access Journals (Sweden)

    Agung Setyo Darmawan

    2013-02-01

    Full Text Available One of potential metals to be used in biomechanical applications is the commercially pure (cp titanium. This material requires a process to improve the mechanical properties of the surface, because it is relatively soft. The purpose of this study is to determine the effect of plasma nitro carburizing process to cp titanium surface hardness. In this study, cp titanium plasma nitro carburizing process is conducted at different temperatures, i.e., at 350°C for 3, 4, and 5 h, and at 450°C for 2, 3, and 4 h, respectively. Hardness tests are then performed on each specimen. The depth of penetration in the hardness test is also recorded; the microstructure captures are also taken using an optical microscope. The results show that the longer processing time, the higher the hardness value. In higher temperature, the hardness values correspond to the increasing temperature. In terms of the depth direction, there is a reduction in hardness value compared to the raw material.

  3. Fiscal 1998 research report. Development of metal forming technology by new energy-saving process (2nd fiscal year); 1998 nendo sho energy gata shin process ni yoru kinzoku seikei gijutsu no kaihatsu (dai 2 nendo)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-03-01

    Based on computer-aided science possible to estimate phase transformation temperatures affecting fine crystal grain control strongly, this research develops the energy- saving production technology for near-net-shape manufacturing of heat-resistant hard materials such as HSS, TiAl and W, by using the new sintering and bonding technology by texture control, complex carbide dispersion technology and pulse discharge sintering based on phase diagram calculation. In fiscal 1998, study was made on optimum alloy composition and heat treatment condition to obtain high-hardness steel with the performance over that of existing HSS by carbide dispersion carburizing process using conventional gas-carburizing facility, based on the data of phase diagram calculation. As a result, the composition and heat treatment condition necessary to obtain a target hardness of Hv1000 were determined. As the research result in both fiscal 1997 and 1998, 10Mo-5V alloy for HSS including a large amount of Mo and V, and 3.5Mo- 1.5V-3Cr alloy for HSS including less than 6% Mo and V are promising as basic composition for the future R and D. (NEDO)

  4. Interior Fracture Mechanism Analysis and Fatigue Life Prediction of Surface-Hardened Gear Steel under Axial Loading

    Directory of Open Access Journals (Sweden)

    Wei Li

    2016-10-01

    Full Text Available The interior defect-induced fracture of surface-hardened metallic materials in the long life region has become a key issue on engineering design. In the present study, the axial loading test with fully reversed condition was performed to examine the fatigue property of a surface-carburized low alloy gear steel in the long life region. Results show that this steel represents the duplex S-N (stress-number of cycles characteristics without conventional fatigue limit related to 107 cycles. Fatigue cracks are all originated from the interior inclusions in the matrix region due to the inhabitation effect of carburized layer. The inclusion induced fracture with fisheye occurs in the short life region below 5 × 105 cycles, whereas the inclusion induced fracture with fine granular area (FGA and fisheye occurs in the long life region beyond 106 cycles. The stress intensity factor range at the front of FGA can be regarded as the threshold value controlling stable growth of interior long crack. The evaluated maximum inclusion size in the effective damage volume of specimen is about 27.29 μm. Considering the size relationships between fisheye and FGA, and inclusion, the developed life prediction method involving crack growth can be acceptable on the basis of the good agreement between the predicted and experimental results.

  5. Bearing and gear steels for aerospace applications

    Science.gov (United States)

    Zaretsky, Erwin V.

    1990-01-01

    Research in metallurgy and processing for bearing and gear steels has resulted in improvements in rolling-element bearing and gear life for aerospace application by a factor of approximately 200 over that obtained in the early 1940's. The selection and specification of a bearing or gear steel is dependent on the integration of multiple metallurgical and physical variables. For most aerospace bearings, through-hardened VIM-VAR AISI M-50 steel is the material of preference. For gears, the preferential material is case-carburized VAR AISI 9310. However, the VAR processing for this material is being replaced by VIM-VAR processing. Since case-carburized VIM-VAR M-50NiL incorporates the desirable qualities of both the AISI M-50 and AISI 9310 materials, optimal life and reliability can be achieved in both bearings and gears with a single steel. Hence, this material offers the promise of a common steel for both bearings and gears for future aerospace applications.

  6. HARDENING-RELATED DEFORMATIONS OF GEAR WHEELS AFTER VACUUM CARBURISING AND QUENCHING IN GAS

    Directory of Open Access Journals (Sweden)

    Wojciech Stachurski

    2017-03-01

    Full Text Available The purpose of modern surface hardening technology is obtaining reproducible, precisely planned parameters of the carburized layer, minimizing the negative phenomena that result in dimensional changes after hardening and making it possible to determine the nature and magnitude of these changes. This concerns mainly the concept of single-piece flow in heat treatment applied for the purposes of mass production, employing a special autonomous 4D Quenching chamber for high pressure gas quenching (HPGQ. The main components of the 4D Quenching chamber include a system of cooling nozzles surrounding the processed item and providing a uniform inflow of cooling gas from all directions (3D and a table rotating together with the item processed, contributing to uniform cooling (4D. Within the framework of this paper there was studied the impact of gear wheel quenching in a 4D Quenching chamber using nitrogen at pressure of 6 and 10 bar on changes in geometry. Geometric measurements of facewidth of gear, hole diameter and outside diameter were performed before and after carburization and quenching. The results obtained allowed us to determine the impact of quenching pressure inside a 4D Quenching chamber on dimensional changes in gear wheels analyzed. The thermo-chemical treatment resulted in a decrease in outside diameters and hole diameters measured and an increase in facewidth of gears.

  7. Prevention of crack initiation in valve bodies under thermal shock

    Energy Technology Data Exchange (ETDEWEB)

    Delmas, J.; Coppolani, P.

    1996-12-01

    On site and testing experience has shown that cracking in valves affects mainly the stellite hardfacing on seats and discs but may also be a concern for valve bodies. Metallurgical investigations conducted by EDF laboratories on many damaged valves have shown that most of the damage had either a chemical, manufacturing, or operating origin with a strong correlation between the origins and the type of damage. The chemical defects were either excess ferritic dilution of stellite or excess carburizing. Excess carburizing leads to a too brittle hardfacing which cracks under excessive stresses induced on the seating surfaces, via the stem, by too high operating thrusts. The same conditions can also induce cracks of the seats in the presence, in the hardfacing, of hidden defects generated during the welding process. Reduction of the number of defects results first from controls during manufacturing, mainly in the thickness of stellite. On the other hand, maintenance must be fitted to the type of defect. In-situ lapping may lead to release of cobalt, resulting in contamination of the circuit. Furthermore, it is ineffectual in the case of a crack through the seating surface, as is often found on globe valves. The use of new technologies of valves with removable seats and cobalt-free alloys solves permanently this kind of problem.

  8. Extended x-ray absorption fine structure investigation of annealed carbon expanded austenite

    DEFF Research Database (Denmark)

    Oddershede, Jette; Christiansen, Thomas L.; Somers, Marcel A. J.;

    2012-01-01

    Carbon expanded austenite synthesized through carburizing of austenitic stainless steel powder at 380°C was annealed at 470°C and investigated with extended X-ray absorption fine structure (EXAFS) and synchrotron powder diffraction (SPD). SPD showed that the samples consisted of carbon expanded...... austenite and Hägg carbide, Ξ-M5C2. EXAFS showed that the Cr atoms were mainly present in environments similar to the carbides Hägg Ξ-M5C2 and M23C6. The environments of the Fe and Ni atoms were concluded to be largely metallic austenite. Light optical micrograph of stainless steel AISI 316 gas......-carburized in a temperature regime around 470°C. The surface zone is converted into carbon expanded austenite; the high interstitial content of carbon dissolved in the surface results in highly favorable materials properties. In the present article the local atomic environment of (annealed) carbon expanded austenite...

  9. Activation of Mo/HZSM-5 for methane aromatization

    Institute of Scientific and Technical Information of China (English)

    Christiaan H. L. Tempelman; Xiaochun Zhu; Emiel J. M. Hensen

    2015-01-01

    The effect of Mo/HZSM-5 pretreatment at 973 K in inert (He), oxidizing (artificial air), and carbu-rizing (CH4/He mixture) atmospheres on its performance in non-oxidative methane dehydroaroma-tization (MDA) was investigated. The effect of post-synthesis silylation on deactivation of external acid sites was also studied. Precarburization resulted in increased aromatic selectivity and im-proved catalyst stability. The benzene selectivity was the highest for the silylated Mo/HZSM-5 cata-lyst (benzene+naphthalene selectivity after 1 h on stream was close to 100%). The deactivation of precarburized zeolites was less pronounced than that of zeolites heated in air or He. During heating in air or He, larger fractions of the molybdenum oxide species diffused into the micropores than during heating in methane. Carburization of the molybdenum oxide species in the micropores dur-ing MDA resulted in the formation of molybdenum carbide particles, and these contributed to pore blocking, making the Brønsted acid sites inaccessible. The formation of molybdenum carbides dur-ing heating in methane resulted in a less mobile Mo phase. It is argued that the presence of molyb-denum carbide particles in the micropores contributes to rapid catalyst deactivation, in addition to the formation of hard coke on the external surface.

  10. Effect of Manganese Incorporation Manner on an Iron-Based Catalyst for Fischer-Tropsch Synthesis

    Institute of Scientific and Technical Information of China (English)

    Tingzhen Li; Yong Yang; Chenghua Zhang; Zhichao Tao; Haijun Wan; Xia An; Hongwei Xiang; Yongwang Li

    2007-01-01

    A systematic study was undertaken to investigate the effects of the manganese incorporation manner on the textural properties,bulk and surface phase compositions,reduction/carburization behaviors,and surface basicity of an iron-based Fischer-Tropsch synthesis (FTS) catalyst.The catalyst samples were characterized by N2 Physisorption,X-ray photoelectron spectroscopy(XPS),H2(or CO) temperature-programmed reduction(TPR),CO2 temperature-programmed desorption(TPD),and Mossbauer spectroscopy.The FTS performance of the catalysts was studied in a slurry-phase continuously stirred tank reactor(CSTR).The characterization results indicated that the manganese promoter incor-porated by using the coprecipitation method could improve the dispersion of iron oxide,and decrease the size of the iron oxide crystallite.The manganese incorporated with the impregnation method is enriched on the catalyst's surface.The manganese promoter added with the impregnation method suppresses the reduction and carburization of the catalyst in H2,CO,and syngas because of the excessive enrichment of manganese on the catalyst surface.The catalyst added manganese using the coprecipitation method has the highest CO conversion (51.9%) and the lowest selectivity for heavy hydrocarbons(C12+).

  11. Eléments d'analyse du cliquetis et de ses effets Elements for Analyzing Knocking and Its Effects

    Directory of Open Access Journals (Sweden)

    Douaud A.

    2006-11-01

    Full Text Available On présente dans cet article une synthèse des travaux théoriques et expérimentaux relatifs à la génération du cliquetis et à ses effets sur le fonctionnement du moteur. L'apparition du cliquetis est décrite par un mécanisme global de délai d'auto-inflammation. Des exemples d'application portant sur l'identification du délai de carburants quelconques et sur l'optimisation de l'ensemble moteurs-carburants documentent cette approche. Le cliquetis a pour conséquence un accroissement de sollicitations mécaniques et thermiques des parois de la chambre de combustion. Des méthodes et résultats d'investigation de ces phénomènes sont présentés. A synthesis is presented of theoretical and experimental research concerning the generating of knocking and its effects on engine running. The appearance of knocking is described by an overall mechanism of autoignition delay. This approach is documented by applied examples concerning the identification of the delay involved with any type of fuel and the optimizing of engine-fuel systems. Knocking causes an increase in mechanical and thermal stresses on combustion-chamber walls. Investigational methods and results concerning these phenomena are described.

  12. Alimentation des moteurs en mélange homogène pauvre Feeding Homogeneous Lean Mixtures to Engines

    Directory of Open Access Journals (Sweden)

    Rayna B.

    2006-11-01

    Full Text Available Les études effectuées dans le cadre de plusieurs conventions de recherche entre l'Institut de Recherche des Transports (IRT et l'Institut Français du Pétrole (IFP associé à d'autres organismes industriels (Régie Nationale des Usines Renault (RNUR, Solex... ont permis a de caractériser l'influence de la préparation physique du mélange air-carburant sur le fonctionnement de moteurs monocylindre et multicylindre. L'effet sur le rendement d'inégalités de richesse entre les cylindres a été estimé à l'aide d'un modèle mathématique de simulation du moteur à allumage commandé ; b d'analyser les défauts inhérents à certains systèmes d'alimentation actuels et d'expérimenter des techniques différentes de formation du mélange carburé (car-burateur à dépression constante, pulvérisation pneumatique du carburant. Les résultats obtenus ont montré notamment que des améliorations ne peuvent résulter que d'un aménagement d'ensemble de tous les éléments du circuit d'admission Investigations carried out under thé terms of several research agreements involving Institut de Recherche des Transports (IRT and Institut Français du Pétrole (IFP associated with other industrial organizations (Régie Nationale des Usines Renault (RNUR, Solex served ta a Characterize thé influence of thé physical preparation of thé air/fuel mixture on thé operating of single-cylinder and multicylinder engines. The effect on thé efficiency of unequal air/fuel ratios among thé cylindres was evaluated by a mathematical model used ta simulate a spark-ignition engine. b Analyze thé inhérent defects of some fuel-supply systems now used and ta experiment with différent techniques of mixture preparation (constant depression car-burettor, pneumatic fuel spraying. The results obtained show, in particulor, that improvements con be produced only by redesigning all thé parts of thé fuel-supply circuit.

  13. L'introduction des composés oxygénés dans le raffinage : impact et stratégies The Introduction of Oxygenated Compounds in Refining: Impact and Strategies

    Directory of Open Access Journals (Sweden)

    Valais M.

    2006-11-01

    Full Text Available L'addition de composés oxygénés dans les carburants est appelée à se développer dans de nombreux pays. Après les Etats-Unis, le Brésil et la République Fédérale d'Allemagne, la France vient d'autoriser (arrêté du 4 octobre 1983 l'addition de méthanol, éthanol, butanols et méthyl tertio butyl éther dans les carburants. Toutefois cette addition est limitée à des valeurs faibles, de 5 à 10 % en volume, dans le but de maintenir les performances des véhicules du parc actuel. Les résultats présentés ici s'appuient sur une étude de modélisation du raffinage visant à appréhender les différents impacts techniques et économiques de l'addition de ces composés oxygénés dans différents types de raffineries. Cette étude montre que l'intérêt de l'addition de chaque composé oxygéné dépend fortement du type de raffinerie considéré, des conditions d'éthylation, de son taux de p-nétration dans le pool des carburants et de son coût d'accès pour le raffineur. The addition of oxygenated compounds to motor fuels is foreseen to develop in numerous countries. After the United States, Brazil and West Germany, France has just authorized (order of October 4, 1983 the addition of methanol, ethanol, butanols and methyltertiobutylether to fuels. However, this addition is limited to small amounts of 5 to 10% by volume in order to maintain the performances of vehicles now in use. The results described here are based on a computer modeling survey of refining, with the aim of assessing the technical and economic impacts that will result from the addition of such oxygenated compounds in gasoline on different types of refineries. This survey shows that the advantage of adding each oxygenated compound depends greatly on the type of refinery considered, on ethylation conditions, on its rate of penetration in the gasoline pool and on its overall cost for the refiners.

  14. Etude expérimentale du cliquetis à haut régime Experimental Study of Hight-Speed Knocking

    Directory of Open Access Journals (Sweden)

    Guibet J. C.

    2006-11-01

    Full Text Available La première partie de cette étude a consisté à observer et à tenter d'interpréter l'action des conditions de fonctionnement et des paramètres de réglage du moteur sur la tendance au cliquetis à haut régime. On a montré ensuite que les différentes familles chimiques d'hydrocarbures qui constituent les carburants classiques présentent chacune un comportement bien distinct en fonction de la richesse, de la pression et de la température d'admission. On a également étudié l'influence de la teneur en plomb du carburant et du type d'alkyle de plomb employé. Quelques expériences ont été effectuées afin de déterminer l'incidence d'une réduction de un point de taux de compression sur l'exigence en octane à haut régime et sur l'action des caractéristiques de composition du carburant. Enfin, en déterminant le pourcentage de cycles soumis au cliquetis pour différentes avances à l'allumage, il a été possible de fournir quelques indications permettant de mieux caractériser l'intensité du phénomène. The first part of this study consists in observing and trying to interpret the effect of operating conditions and engine tuning parameters on the tendency for high-speed knocking to appear. The different chemical families of the hydrocarbons making up conventional fuels are shown to each have a quite different behavior depending on the fuel-air equivalency ratio and the admission pressure and temperature. The influence of the lead content in the fuel and of the type of lead alkyl used is also studied. Some experiments were performed to determine the influence of a one-point reduction in the compression ratio on the high-speed octane requirement and on the effect of fuel composition properties. Lastly, by determing the percentage of cycles accompanied by knocking at different spark advances, some indications were found for better characterizing the intensity of the phenomenon.

  15. BIOCARBURANTS PSA Peugeot Citroën et les biocarburants

    Directory of Open Access Journals (Sweden)

    Maurer Béatrice

    2002-09-01

    Full Text Available Les biocarburants représentent une filière essentielle pour PSA Peugeot Citroën dans le cadre de la protection de l’environnement, un axe stratégique majeur pour le groupe - de la production de ses véhicules au recyclage, de la qualité de l’air à l’effet de serre et au développement d’énergies renouvelables. Depuis plusieurs années, PSA a intégré la filière huiles végétales/biocarburants dans ses activités pour atteindre ses objectifs globaux d’innovation et de croissance. De nombreuses flottes de véhicules circulent en France avec du gazole contenant 30 % de biocarburant issu des oléagineux : une expérience réussie, qui dure depuis plus de dix ans. Le constructeur est favorable à l’utilisation de biocarburants en mélange dans les carburants pétroliers conventionnels, essence et gazole - une voie qui présente plusieurs avantages : * Un bilan CO2 global favorable (par absorption de CO2 lors de la photosynthèse de la plante-source, qui contribue à limiter « l’effet de serre ». * Une source complémentaire de carburant pour réduire les importations de pétrole (et de gazole. * Un soutien au secteur agricole (débouché supplémentaire, dans le cadre de la valorisation des terres en jachère. Issus de la transformation des céréales ou de la betterave à sucre, ou des plantes oléagineuses comme le colza, le tournesol ou le soja, les biocarburants sont par essence des énergies renouvelables. Outre leur bilan exceptionnellement favorable pour lutter contre l’effet de serre, ces carburants offrent de réelles performances environnementales, en particulier par la réduction des émissions de particules (cas des EMHV.

  16. Le Gaz Naturel Véhicule Natural Gas for Vehicles

    Directory of Open Access Journals (Sweden)

    De Chauveron S.

    2006-11-01

    Full Text Available Cet article présente le GNV (Gaz Naturel Véhicule. Le GNV a en effet de sérieux atouts, à la fois comme carburant de substitution et comme carburant propre. Ces atouts sont aussi bien économiques que techniques. La première partie est consacrée aux enjeux du développement du GNV. Les premiers pays utilisateurs ont été ceux qui disposent sur leur sol de ressources de gaz naturel. Aujourd'hui, alors que de nombreux pays doivent faire face à l'inquiétude croissante relative à l'augmentation de la pollution urbaine, le gaz naturel apparaît également comme un carburant propre, permettant de réduire rapidement les émissions de polluants des véhicules. Dans une deuxième partie, nous donnons une description technique sommaire des stations GNV et des véhicules GNV. Il s'agit de familiariser le lecteur avec les quelques spécificités techniques du GNV, par rapport à l'essence et au gazole. On constatera d'ailleurs que les technologies GNV sont très proches des technologies classiques. Enfin, la dernière partie est consacrée aux actions en cours, qui permettront le développement du GNV en France et en Europe : programmes de recherche, réduction des coûts de la filière, actions réglementaires, communication, etc. This article presents compressed natural gas for vehicles (CNG, which can provide considerable advantages both as an alternative fuel and as a clean fuel. These assets are not only economic but also technical. The first part deals with what is at stake in developing natural gas as a motor fuel. The first countries to use CNG were those with natural gas resources in their subsoil. Today, with a large number of countries having to cope with growing concern about increasing urban pollution, natural gas is also seen as a clean fuel that can help cut vehicle pollutant emissions dramatically. In the second part a brief technical description is given of CNG stations and vehicles, with the aim of acquainting the reader with

  17. 硬质合金麻花钻钻削不锈钢Q345深孔的试验研究%Experimental Study for Solid Carbide in Stainless Steel Q345 Drilling Deep Hole

    Institute of Scientific and Technical Information of China (English)

    张波; 许辉; 胡江林

    2012-01-01

    整体硬质合金钻头在加工塑性材料时断屑、排屑比较困难.分析实际加工条件和被加工材料的特征后,替换了原来使用的进口“皇冠”钻头.本文介绍替换的试验过程、结果,经试验验证超过了客户期望的寿命.%Problem of breaking chip and the chip draining in the machining process when deep-hole drilling on carbu-rized Q345. The characteristics of the material drilling are investigated and novel dill is replacement the crown drilloExperiments and test - run reveal that the tool-life of the drill increases by many times in comparison with that of the conventional ones.

  18. Vie tribologique à chaud et température interfaciale dans des contacts céramiques

    OpenAIRE

    Dalverny, Olivier

    1998-01-01

    Le frottement et l'usure de différents couples de céramiques oxydes (alumines) et non-oxyde (carbure de tungstène à liant cobalt) ont été étudiés à température ambiante et à haute température en s'attachant à mettre en relief l'incidence des phénomènes thermiques sur le comportement tribologique de ces matériaux. Un montage expérimental a tout d'abord été conçu et réalisé spécialement pour cette étude. Il permet la conduite d'essais de frottement en configuration pion-disque de l'ambiante à 9...

  19. High temperature materials for radioactive waste incineration and vitrification. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Bickford, D F; Ondrejcin, R S; Salley, L

    1986-01-01

    Incineration or vitrification of radioactive waste subjects equipment to alkaline or acidic fluxing, oxidation, sulfidation, carburization, and thermal shock. It is necessary to select appropriate materials of construction and control operating conditions to avoid rapid equipment failure. Nickel- and cobalt-based alloys with high chromium or aluminum content and aluminum oxide/chromium oxide refractories with high chromium oxide content have provided the best service in pilot-scale melter tests. Inconel 690 and Monofrax K-3 are being used for waste vitrification. Haynes 188 and high alumina refractory are undergoing pilot scale tests for incineration equipment. Laboratory tests indicate that alloys and refractories containing still higher concentrations of chromium or chromium oxide, such as Inconel 671 and Monofrax E, may provide superior resistance to attack in glass melter environments.

  20. Insights on finite size effects in Ab-initio study of CO adsorption and dissociation on Fe 110 surface

    CERN Document Server

    Chakrabarty, Aurab; Mousseau, Normand; Becquart, Charlotte S; Mellouhi, Fadwa El

    2016-01-01

    Adsorption and dissociation of hydrocarbons on metallic surfaces represent crucial steps to carburization of metal. Here, we use density functional theory total energy calculations with the climbing-image nudged elastic band method to estimate the adsorption energies and dissociation barriers for different CO coverages with surface supercells of different sizes. For the absorption of CO, the contribution from van der Waals interaction in the computation of adsorption parameters is found important in small systems with high CO-coverages. The dissociation process involves carbon insertion into the Fe surface causing a lattice deformation that requires a larger surface system for unrestricted relaxation. We show that, in larger surface systems associated with dilute CO-coverages, the dissociation barrier is significantly decreased. The elastic deformation of the surface is generic and can potentially applicable for all similar metal-hydrocarbon reactions and therefore a dilute coverage is necessary for the simul...