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Correlations of Ni Contents, Formation of Reversed Austenite and Toughness for Ni-Containing Cryogenic Steels 被引量:10
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作者 Meng Wang Zhen-Yu Liu Cheng-Gang Li 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2017年第3期238-249,共12页
It has been widely demonstrated that addition of Ni in low-carbon steels can effectively improve the cryogenic toughness, but the mechanism behind it has yet to be clarified. In the present work, the evolutions of mic... It has been widely demonstrated that addition of Ni in low-carbon steels can effectively improve the cryogenic toughness, but the mechanism behind it has yet to be clarified. In the present work, the evolutions of microstructure and mechanical properties after quenching and tempering for Ni-containing cryogenic steels with different Ni contents (3.5-9 wt%) were investigated. The results showed that after quenching and tempering, the Ni-containing cryogenic steels were composed of tempered martensite and reversed austenite. The volume fraction of reversed austenite has increased from 0 up to 6.3% when the Ni content increases from 3.5% to 9%. The Charpy impact tests indicated that the low- temperature toughness was markedly improved with the increase in Ni content, which can be correlated with the increase in reversed austenite amount. The main contribution of reversed austenite to the toughness lies in: (1) the elimination of cementite precipitates improved the plastic deformation capacity of matrix, and (2) the crack propagation is hindered through plastic deformation. 展开更多
关键词 ni-containing cryogenic steel Microstructure Reversed austenite Impact toughness Crackpropagation
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Effect of cryogenic rolling and annealing on the microstructure evolution and mechanical properties of 304 stainless steel 被引量:4
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作者 Jin-tao Shi Long-gang Hou +2 位作者 Jin-rong Zuo Lin-zhong Zhuang Ji-shan Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2017年第6期638-645,共8页
Metastable 304 austenitic stainless steel was subjected to rolling at cryogenic and room temperatures, followed by annealing at different temperatures from 500 to 950°C. Phase transition during annealing was stud... Metastable 304 austenitic stainless steel was subjected to rolling at cryogenic and room temperatures, followed by annealing at different temperatures from 500 to 950°C. Phase transition during annealing was studied using X-ray diffractometry. Transmission electron microscopy and electron backscattered diffraction were used to characterize the martensite transformation and the distribution of austenite grain size after annealing. The recrystallization mechanism during cryogenic rolling was a reversal of martensite into austenite and austenite growth. Cryogenic rolling followed by annealing refined grains to 4.7 μm compared with 8.7 μm achieved under room-temperature rolling, as shown by the electron backscattered diffraction images. Tensile tests showed significantly improved mechanical properties after cryogenic rolling as the yield strength was enhanced by 47% compared with room-temperature rolling. 展开更多
关键词 STAINLESS steel cryogenic ROLLING ANNEALING MICROSTRUCTURAL evolution MECHANICAL properties recrystallization
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Experimental Study on Bonding Properties Between Steel Strand and Concrete at Cryogenic Temperatures 被引量:5
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作者 谢剑 爱的歌 +1 位作者 雷光成 聂治盟 《Transactions of Tianjin University》 EI CAS 2016年第4期308-316,共9页
To study the bonding properties between steel strand and concrete at room and cryogenic temperatures, a series of center pullout experiments were conducted on 96 bonding anchorage specimens at the lowest temperature o... To study the bonding properties between steel strand and concrete at room and cryogenic temperatures, a series of center pullout experiments were conducted on 96 bonding anchorage specimens at the lowest temperature of-165 ℃. The impacts on the bonding property of such parameters as the temperature, concrete strength, the relative concrete cover thickness, and the relative anchorage length were analyzed. The test results indicate that the changes in temperature have a clear effect on the bonding property between steel strand and concrete. As the temperature decreases, the bond stress, which corresponds to a 1 mm slip of steel strand in relation to concrete, and the ultimate bond strength initially increase and subsequently decrease at the inflection point of-80 ℃. The impact of the concrete strength on the bonding property, as shown by the tensile strength and the moisture content interaction, indicates that the bond stress vs concrete strength curve initially increases and later decreases with a decrease in temperature; the bond stress vs concrete cover thickness curve linearly increases, but the bond stress vs anchorage length curve linearly decreases at first and finally levels off. 展开更多
关键词 CONCRETE cryogenic temperature bonding property steel strand
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STUDY ON CRYOGENIC PHASE CHANGE & WEAR CHARACTERISTIC OF HIGH SPEED STEEL 被引量:4
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作者 M.C.Huang C.H.Gao L.G.Huang 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2003年第6期524-530,共7页
The microscopic structure change rule in high speed steel (HSS) after an additional cryogenic treatment was studied in this paper. Highly dispersed nano-carbide (η-Fe2 C) separated from tempering martensite was found... The microscopic structure change rule in high speed steel (HSS) after an additional cryogenic treatment was studied in this paper. Highly dispersed nano-carbide (η-Fe2 C) separated from tempering martensite was found distributed on twin planes of marten-site and dislocation places. Retained austenite was found sheared into martensite and nano-carbide separated at the same time. In addition, the tempering martensite was fine-grained. The stated changes of HSS evidently improve the lifespan of HSS cutter and fully show the advantages of nano-structure. The cryogenic treatment of HSS also improves the roughness of HSS cutter (decrease Ra number by about 50%) and greatly increases the wear resistance of HSS cutter. Further experiments on the wear characteristic of HSS cutter supported the findings mentioned above. The stated HSS treatment technology would implement nano-structure of traditional tool steel through phase change. It could be a new method to improve the performance of HSS cutter. 展开更多
关键词 high speed steel cryogenic treatment phase change wear char-acteristic NANO-STRUCTURE
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Effect of deep cryogenic treatment on the formation of nano-sized carbides and the wear behavior of D2 tool steel 被引量:3
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作者 Kamran Amini Amin Akhbarizadeh Sirus Javadpour 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第9期795-799,共5页
The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffracti... The effect of deep cryogenic treatment on the microstructure, hardness, and wear behavior of D2 tool steel was studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), hardness test, pin-on-disk wear test, and the reciprocating pin-on-fiat wear test. The results show that deep cryogenic treatment eliminates retained austenite, makes a better carbide distribution, and increases the carbide content. Furthermore, some new nano-sized carbides form during the deep cryogenic treatment, thereby increasing the hardness and improving the wear behavior of the samples. 展开更多
关键词 cryogenic treatment tool steel nano-sized carbides wear resistance HARDNESS AUSTENITE
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Effect of deep cryogenic treatment on the properties of 80CrMo12 5 tool steel 被引量:2
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作者 Kamran Amini Said Nategh +1 位作者 Ali Shafyei Ahmad Rezaeian 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2012年第1期30-37,共8页
The effect of deep cryogenic treatment on the mechanical properties of 80CrMo 12 5 tool steel was investigated. Moreover, the effects of stabilization (holding at room temperature for some periods before deep cryogen... The effect of deep cryogenic treatment on the mechanical properties of 80CrMo 12 5 tool steel was investigated. Moreover, the effects of stabilization (holding at room temperature for some periods before deep cryogenic treatment) and tempering before deep cryogenic treatment were studied. The results show that deep cryogenic treatment can eliminate the retained austenite, making a better carbide distribu- tion and a higher carbide amount. As a result, a remarkable improvement in wear resistance of cryogenically treated specimens is observed. Moreover, the ultimate tensile strength increases, and the toughness of the sample decreases. It is also found that both stabilization and tem- pering before deep cryogenic treatment decrease the wear resistance, hardness, and carbides homogeneity compared to the deep cryogeni- cally treated samples. It is concluded that deep cryogenic treatment should be performed without any delay on samples after quenching to reach the highest wear resistance and hardness. 展开更多
关键词 tool steel cryogenic treatment STABILIZATION wear resistance tensile strength HARDNESS carbides
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FORMATION OF PRECIPITATED AUSTENITE IN 9%Ni STEEL AND ITS PERFORMANCE AT CRYOGENIC TEMPERATURE 被引量:1
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作者 LEI Ming GUO Yunyi Institute of Metal Research,Academia Sinica,Shenyang,China Associate Professor,Institute of Metal Research,Academia Sinica,Shenyang,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1989年第4期244-248,共5页
The formation of precipitated austenite in 9% Ni steel exposed at the temperature of α+γ re- gion and its influence on impact tonghness at cryogenic temperature have been studied. Austenite-rich and ferrite-rich ban... The formation of precipitated austenite in 9% Ni steel exposed at the temperature of α+γ re- gion and its influence on impact tonghness at cryogenic temperature have been studied. Austenite-rich and ferrite-rich bands are formed during soaking because of the re-distribu- tion of elements of C,N and Ni.The former phase is enriched of Ni,Mn,C and N,while the latter one is relatively pure.Part of the austenite formed at intermediate temperatures trans- forms into martensite when the steel is cooled down to room temperature.The complex struc- ture which consists of fine martensite and austenite exhibits a moderate strength and high enough cryogenic toughness.The austenite enriched of C,N and Ni is still stable at the cryogenic temperature.The tearing ridges on the impact fracture surface is densely occupied by the precipitated austenite,elongated along the tearing direction.One of the important cause of the excellent eryogenic properties is that the precipitated austenite absorbs the impurities and thus purifies the matrix of the steel. 展开更多
关键词 9%Ni steel precipitated austenite cryogenic toughness
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Machinability Investigation and Optimization of Process Parameters in Cryogenic Assisted Sustainable Turning of AISI‑L6 Tool Steel 被引量:1
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作者 JAMIL Muhammad HAQ Emran ul +3 位作者 KHAN Aqib Mashood GUPTA Munish Kumar LI Liang SONG Qinghua 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2020年第3期403-415,共13页
The application of cutting fluid is significantly increased in the machining sector to improve productivity.However,the inherent characteristics of cutting fluids on ecology,environment,and society shift the interest ... The application of cutting fluid is significantly increased in the machining sector to improve productivity.However,the inherent characteristics of cutting fluids on ecology,environment,and society shift the interest of researchers to work on environmentally friendly cooling conditions such as cryogenic cooling.Here,the effect of cutting speed and feed rate on the machining performance of the AISI‑L6 tool steel is investigated under cryogenic cooling conditions.Then,the L9 Taguchi based grey relational analysis(GRA)is conducted to investigate the essential machining indices such as cutting energy,surface roughness,tool wear,and material removal rate(MRR).The results indicate that the cutting speed of 160 m/min and feed rate of 0.16 mm/r are the optimum parameters that significantly improves the machining performance of AISI‑L6 tool steel. 展开更多
关键词 sustainable manufacturing cryogenic machining hardened steel energy consumption tool lif
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Investigation on the temperature distribution and strength of flat steel ribbon wound cryogenic high-pressure vessel 被引量:1
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作者 CUI Xiao-long CHEN Guang-ming 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第2期210-215,共6页
By analyzing heat transfer on the wall of fiat steel ribbon wound vessel (FSRWV), a numerical model of temperature distribution on the entire wall (including inner core wall, flat steel ribbons, outside cylinder of... By analyzing heat transfer on the wall of fiat steel ribbon wound vessel (FSRWV), a numerical model of temperature distribution on the entire wall (including inner core wall, flat steel ribbons, outside cylinder of jacket and insulating layer) was established by the authors. With the model, the temperature distribution and the length change in the vessel walls and flat steel ribbons in low temperature are calculated and analyzed. The results show that the flat steel ribbon wound cryogenic high-pressure vessel is simpler in structure, safer and easier to manufacture than those of conventional ones. 展开更多
关键词 cryogenic high-pressure vessel Flat steel ribbon wound vessel (FSRWV) Temperature distribution Numerical simulation
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Influence of soaking time in deep cryogenic treatment on the microstructure and mechanical properties of low-alloy medium-carbon HY-TUF steel 被引量:1
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作者 Ahmad Zare S.R.Hosseini 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2016年第6期658-666,共9页
The influence of soaking time in deep cryogenic treatment on the tensile and impact properties of low-alloy medium-carbon HY-TUF steel was investigated in this study. Microstructural studies based on phase distributio... The influence of soaking time in deep cryogenic treatment on the tensile and impact properties of low-alloy medium-carbon HY-TUF steel was investigated in this study. Microstructural studies based on phase distribution mapping by electron backscatter diffraction show that the deep cryogenic process causes a decrease in the content of retained austenite and an increase in the volume fraction of η-carbide with increasing soaking time up to 48 h. The decrease in the content of retained austenite from ~1.23vol% to 0.48vol% suggests an isothermal martensitic transformation at 77 K. The η-type precipitates formed in deep cryogenic-treated martensite over 48 h have the Hirotsu and Nagakura orientation relation with the martensitic matrix. Furthermore, a high coherency between η-carbide and the martensitic matrix is observed by high-resolution transmission electron microscopy. The variations in macrohardness, yield strength, ultimate tensile strength, and ductility with soaking time in the deep cryogenic process show a peak/plateau trend. 展开更多
关键词 low alloy steel medium carbon steel cryogenic treatment microstructure mechanical properties fractography
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Phenomenological modelling of flow behaviour of 20MnMoNi55 reactor pressure vessel steel at cryogenic temperature with different strain rates
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作者 Swagatam Paul Partha Dey +3 位作者 Snehasish Bhattacharjee Sanjib Kumar Acharyya Prasanta Sahoo Jayanta Chattopadhyay 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2019年第3期326-337,共12页
In the present study a phenomenological constitutive model is developed to describe the flow behaviour of 20MnMoNi55 low carbon reactor pressure vessel (RPV) steel at sub-zero temperature under different strain rates.... In the present study a phenomenological constitutive model is developed to describe the flow behaviour of 20MnMoNi55 low carbon reactor pressure vessel (RPV) steel at sub-zero temperature under different strain rates. A set of uniaxial tensile tests is done with the variation of strain rates and temperature ranging from 10^-4s^-1 to 10^-1s^-1 and -80℃ to 140℃ respectively. From the experimental data, family of flow curves at different temperatures and strain rates are generated and fitted exponentially. The strain rate and temperature dependence of the coefficients of the exponential flow curves are extracted from these curves and characterised through a general phenomenological constitutive coupled equation. The coefficients of this coupled equation are optimised using genetic algorithm. Finite element simulation of tensile tests at different strain rates and temperatures are done using this coupled equation in material model of Abaqus FEA software and validated with experimental results. The novelties of proposed model are:(a) it can predict precisely the flow behaviour of tensile tests (b) it is a simple form of equation where fitting parameters are both function of strain rate ratio and temperature ratio,(c) it has ability to characterize flow behaviour with decreasing subzero temperatures and increasing strain rates. 展开更多
关键词 Flow BEHAVIOUR RPV steel cryogenic temperature STRAIN RATE
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Influence of cryogenic treatment on the wear characteristics of 100Cr6 bearing steel
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作者 R.Sri Siva D.Mohan Lal +1 位作者 P.Kesavan Nair M.Arockia Jaswin 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第1期46-51,共6页
A series of reciprocating wear tests were performed on the deep cryogenically treated and conventionally heat-treated samples of 100Cr6 bearing steel to study the wear resistance. The worn surfaces as well as the wear... A series of reciprocating wear tests were performed on the deep cryogenically treated and conventionally heat-treated samples of 100Cr6 bearing steel to study the wear resistance. The worn surfaces as well as the wear debris were analyzed by scanning electron microscopy. The improvement in wear resistance of the deep cryogenically treated samples ranges from 49% to 52%. This significant improvement in wear resistance can be attributed to finer carbide precipitation in the tempered martensitie matrix and the transformation of retained aus- tenite into martensite. X-ray diffraction analysis shows that the volume fraction of retained austenite in the conventionally heat-treated samples is 14% and that of the deep cryogenically treated samples is only 3%. 展开更多
关键词 bearing steel cryogenic treatment wear resistance carbides MARTENSITE
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CRYOGENIC MECHANICAL BEHAVIOUR OF MARAGING STEEL CONTAINING HYDROGEN
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作者 LIU Zhonghao CHEN Lian Institute of Metal Research,Academia Sinica,Shenyang,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1991年第1期47-54,共8页
Within the range of 77 to 295 K,the strength and plastieity of 18Ni maraging steel increase with decreasing temperature and decrease with increasing hydrogen content.The susceptibility to hydrogen embrittlement of the... Within the range of 77 to 295 K,the strength and plastieity of 18Ni maraging steel increase with decreasing temperature and decrease with increasing hydrogen content.The susceptibility to hydrogen embrittlement of the maraged specimens is superior to solid solution ones.The dislocations after plastically deforming will tangle into dislocation cells which reduce thermselves in size as the temperature decreases,and coarsen as the hydrogen content in- creases.No cryogenie deformation twin was found.The tensile fracture surfaces of the solu- tion and maraged specimens containing 5.90 ppm hydrogen under 295 to 223 K are revealed as quasi-cleavage and intergranular features respectively and as transgranular ones under other experimental conditions.The influence of hydrogen on the mechanical behaviour of steel and the mechanism of hydrogen induced deformation and fracture are discussed. Research Assistant, Institute of Metal Research,Academia Sinica, Shenyang 110015,China 展开更多
关键词 maraging steel FRACTURE hydrogen embrittlement cryogenic property
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Effect of Cryogenic and QPQ Compound Treatment on the Microstructures and Performance of High Speed Steel
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作者 LUO Defu LI Shen 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2012年第1期184-189,共6页
China’s High-speed steel cutting tools hold a considerable share in the global market. However, the overproduction of low-end HSS tools causes serious resource waste and low efficiency, which has become one of the ma... China’s High-speed steel cutting tools hold a considerable share in the global market. However, the overproduction of low-end HSS tools causes serious resource waste and low efficiency, which has become one of the major problems in the tool industry in China. So a new Surface Modification technology is developed, which can make the low-end HSS tools into the high-end ones. On the analysis of the mechanism of cryogenic and quenching-polish-quenching(QPQ), the cryogenic and QPQ compound treatment are studied by using ?8 HSS(M2) drills. The nitriding layer and the base of the drill bit are Studied and analyzed, and the mechanism of compound treatment is discussed by the technological parameters adjustment and the combination test of cryogenic, nitrogen, tempering procedures, and several analysis methods such as the optics metallographic microscope, the scanning electronic microscope (SEM), X-ray diffraction and micro hardness. The cutting test is done on the drills by cryogenic treatment, QPQ treatment and cryogenic and QPQ compound treatment separately. The results indicates that the cutting life of HSS (M2) drill can be increased dramatically by cryogenic and QPQ compound treatment. 展开更多
关键词 high-speed steel (HSS) cryogenic treatment quenching-polish-quenching (QPQ)
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CRITICAL NOTCH(CRACK)SIZE AS A CHARACTERISTIC PARAMETER EVALUATING CRYOGENIC BRITTLENESS IN LOW CARBON STEEL
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作者 LI Daoming YAO Mei Harbin Institute of Technology,Harbin,China Box 617,Harbin Institute of Technology,Harbin,China 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1989年第3期208-214,共7页
The effect of notch depth on the cryogenic fracture behavior has been studied using a low car- bon steel.An analysis was made for the fracture features at T_c~*(cryogenic brittleness-char- acteristic temperature)at wh... The effect of notch depth on the cryogenic fracture behavior has been studied using a low car- bon steel.An analysis was made for the fracture features at T_c~*(cryogenic brittleness-char- acteristic temperature)at which the facture load reaehes a valley value.Furthermore,accord- ing to the experimental results and engineering design practice,a concept of critical notch (crack)'size for cryogenic brittleness,a_c,as well as its limit value a_c~*,was put forward and recommended to be a basic characteristic parameter for controlling the brittleness. Mathematical derivation was carried out to give the expression of a_c and a_c~*,the reliability of which was verified by the modeling tests under both static and cyclic loading conditions. 展开更多
关键词 low carbon steel cryogenic brittleness notch(crack)size
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EVALUATION OF EMBRITTLEMENT BEHAVIOR DUETO SENSITIZATION IN A CRYOGENIC AUSTENITICSTAINLESS STEEL BY MEANS OF SMALL PUNCHAND FRACTURE TOUGHNESS TESTS
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作者 S.C Liu(Research Institute for Fracture Technology Faculty of Engineering, Tohoku University, Sendai, Japan on leave from Dalian Railway Institute, Dalian 116028, China)II-Hyun Kown T Hashida and H Takahashi(Research Institute for nacture Technology, Fa 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 1997年第3期239-248,共10页
In order to evaluate the tendency of mechanical properties degrudation due to weld-ing and other processing in materials used for supporting coils in super conducting rnaguets utilized in thermonuclear jusion reactore... In order to evaluate the tendency of mechanical properties degrudation due to weld-ing and other processing in materials used for supporting coils in super conducting rnaguets utilized in thermonuclear jusion reactore, a small punch (SP) test was used.This test, which was originally developed to study irradiation damage using miniatursized specimens was performed at 77 and 4 K for solution treated and sensitized JN1 austenitic stainless steel, a candidate cryogenic structural material. The area under the load-deflection curve up to the maximum applied load in SP test was defined as the SP enerpy, to characterize the resistance to fracture. Although solution treated material exhibited ductile fracture mode with high SP enerpy, embrittlement behavior due to sensitization at 650-800°for 1-5 h was shown clearlg by SP test with brittle intergranular fracture and decreased SP enerpy. Comparison of the results obtained by SP test with those by fracture toughness test showed the usefulness of SP test for evaluation of sensitization induced embrittlement at cryogenic temperature. The re-sults obtained in this study can be very usefol in predicting the degradation due to welding and other processing in cryogenic materials. 展开更多
关键词 small punch test fracture toughness test cryogenic fracture behavior JN1 austenitic stainless steel embrittlement due to sensitization
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Influence of Deep Cryogenic Treatment (DCT) on Thermo Mechanical Performance of AISI H13 Tool Steel
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作者 Valmik Bhawar Shreyans Khot +2 位作者 Prakash Kattire Mohan Mehta Rajkumar Singh 《Journal of Materials Science and Chemical Engineering》 2017年第1期91-101,共11页
Deep cryogenic treatment (DCT) is one of the most recent processes being used to treat tool steels. It is a supplementary treatment where components are treated below subzero temperatures for several cryo-soaking hour... Deep cryogenic treatment (DCT) is one of the most recent processes being used to treat tool steels. It is a supplementary treatment where components are treated below subzero temperatures for several cryo-soaking hours. This paper focuses on to study the effect of deep cryogenic treatment on Thermo mechanical properties of AISI H-13 tool steel. Deep cryogenic treatment at 32 hours of cryo-soaking time is applied and thermo mechanical performance of tool steel was analyzed by using pin on disk high temperature wear testing and stress rupture testings. The microstructural evolutions during DCT were evaluated by using scanning electron microscope (SEM). It was observed that microstructural modifications like increase in carbide density, fine and uniform martensitic structure during DCT had significantly improved properties. 展开更多
关键词 cryogenic Treatment Wear Resistance TOOL steel H-13 TOOL steel
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Influence of Cryogenic Treatment on Microstructure and Properties Improvement of Die Steel
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作者 Shangtan Liu Xiaochun Wu +2 位作者 Lei Shi Yiwen Wu Wei Qu 《Journal of Materials Science and Chemical Engineering》 2015年第9期37-46,共10页
Cryogenic treatment has been increasingly applied to enhance the hardness, antiwear ability and fatigue performance of die steel. On the basis of reading a large number of research papers and references across the wor... Cryogenic treatment has been increasingly applied to enhance the hardness, antiwear ability and fatigue performance of die steel. On the basis of reading a large number of research papers and references across the world, the author makes a detailed analysis and brief summary of the influence of cryogenic treatment on microstructure after quenching process or quenching plus tempering process, on first and second carbides, on content of retained austenite, on surface hardness, on mechanical properties and antiwear ability of die steels. It’s proved that cryogenic treatment on die steel significantly improves its hardness, antiwear capacity and service life. It’s the cryogenic process to make die steel have higher hardness, better antiwear ability, better ductility and longer service life because cryogenic process actually has a good influence on die steel of its microstructure, retained austenite volume and amount and size of the second carbide. 展开更多
关键词 Die steel cryogenic Treatment RETAINED AUSTENITE The Second CARBIDE ANTIWEAR Ability
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On The Enhancement of Wear Resistance of Hardened Carbon Tool Steel (AISI 1095) With Cryogenic Quenching
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作者 V.Soundararajan N.Alagurmurthi K.Palaniradja 《材料热处理学报》 EI CAS CSCD 北大核心 2004年第5期531-535,共5页
Many experimental investigations reveal that it is very difficult to have a completely martensitic structure by any hardening process. Some amount of austenite is generally present in the hardened steel. This austenit... Many experimental investigations reveal that it is very difficult to have a completely martensitic structure by any hardening process. Some amount of austenite is generally present in the hardened steel. This austenite existing along with martensite is normally referred as the retained austenite. The presence of retained austenite greatly reduces the mechanical properties and such steels do not develop maximum hardness even after cooling at rates higher than the critical cooling rates. Strength can be improved in hardened steels containing retained austenite by a process known as cryogenic quenching. Untransformed austenite is converted into martensite by this treatment. This conversion of retained austenite into martensite results in increased hardness, wear resistance and dimensional stability of steel. Wear can be defined as the progressive loss of materials from the operating surface of a body occurring as a result of relative motion at the surface. Hardness, load, speed, surface roughness, temperature are the major factors which influences wear. Many studies on wear indicate that increasing hardness decreases the wear of a material. With this in mind, to study the surface wear on a surface modified (Cryogenic treated) steel material an attempt has been made in this paper. In this study as a Part -I Hardening was carried out on carbon tool steel (AISI 1095) of different L/D ratio with conventional quenchants like purified water, aqueous solution and Hot mineral oil. As a Part -II hardening was followed by quenching was carried out as said in Part-1 and the hardened specimen were quenched in liquid Nitrogen which is at sub zero condition. The specimens were tested for its microstructure, hardness and wear loss. The results were compared and analyzed. The alloying elements increases the content of retained austenite hence the material used was AISI1095 (Carbon 0.9%, Si 0.2%, MnO.4% and the rest Iron) 展开更多
关键词 AISI1095钢 液态氮 低温淬火 抗磨损性
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FEM simulation and experimental verification of temperature field and phase transformation in deep cryogenic treatment 被引量:4
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作者 黎军顽 汤磊磊 +1 位作者 李绍宏 吴晓春 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2421-2430,共10页
Combining with the low temperature material properties and the boiling heat transfer coefficient of specimen immersed in the liquid nitrogen, a numerical model based on metallo-thermo-mechanical couple theory was esta... Combining with the low temperature material properties and the boiling heat transfer coefficient of specimen immersed in the liquid nitrogen, a numerical model based on metallo-thermo-mechanical couple theory was established to reproduce the deep cryogenic treatment (DCT) process of a newly developed cold work die steel Cr8Mo2SiV (SDC99). Moreover, an experimental setup for rapid temperature measurement was designed to validate the simulation results. The investigation suggests that the differences in temperature and cooling rate between the surface and core of specimen are very significant. However, it should be emphasized that the acute temperature and cooling rate changes during DCT are mainly concentrated on the specimen surface region about 1/3 of the sample thickness. Subjected to DCT, the retained austenite of quenched specimen continues to transform to martensite and finally its phase volume fraction reduces to 2.3%. The predicted results are coincident well with the experimental data, which demonstrates that the numerical model employed in this study can accurately capture the variation characteristics of temperature and microstructure fields during DCT and provide a theoretical guidance for making the reasonable DCT procedure. 展开更多
关键词 deep cryogenic treatment boiling heat transfer coefficient finite element method phase transformation cold work tool steel
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