XIAN Aiping LI Peiji CHEN Wenxiu WANG Yikang Institute of Metal Research
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Academia Sinica
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Shenyang
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ChinaCHEN Renvi MEI Dongsheng Panzhihua Institute of Iron and Steel Research
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Ministry of Metallurgical Industry
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Panzhihua
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China associate professor
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Institute of Metal Research
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Academia Sinica
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Shenyang 110015
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China
金属学报(英文版)
The determination of dffusible hydrogen in U71Mn heavy rail steel,and hydrogen diffusivity as well as the hydrogen distribution in the cross section of blooms with stack cooling were stu- died.The results showed that,most of the hydrogen in blooms of heavv rail steel is diffusible, the hydrogen diffusivity in U71Mn rail steel blooms at room temperature is(0.85—1.02)× 10~(-6)cm~2/s,after stack cooling,the hydrogen content in bloom will decrease greatly which is helpful to form the flake-free phenomenon in the heavy rail produced by Panzhihua Iron and Steel Company.
关键词:
rail steel
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Liu Zhengyi Fu Jian Zhuang Yuzhi South China University of Technology
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Guangzhou
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China Correspondent:LIU Zhengyi professor
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Dept.of Mechanical Engineering No.2
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South China University of Technology
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Guangzhou
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China
金属学报(英文版)
The nature of“white layer”found in 55SiMnMo steel subjected to friction test has been stu- died using TEM,SEM,X-ray diffraction and EPMA techniques.It is shown that the struc- ture of the“white laver”on the rubbing surface is duplex,consisting of a special martensite and some austenite.This layer may be 25—50 μm thick.It is ultrafine,with grain diametric approximately 30 nm.Its micro-hardness may be as high as Hm 1500 and is capable of cut- ting glass.It has superb corrosion resistance and resists tempering.Its mierostructure and hardness undergo changes only when the steel is tempered above 500℃.
关键词:
friction
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CHEN Zhongmin XIE Faqin SHI Zhengxing WANG Leyi FU Hengzhi Northwestern Polytechnical University
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Xi'an
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China
金属学报(英文版)
Characteristics of magnetic hardening in cast-hot pressed magnet Pr_(19)Fe_(74.5)B_5Cu_(1.5)were stu- died.The microstructure features and virgin magnetization curve reveal a nucleation control- led coercivity mechanism.Regression analysis shows that the intrinsic coercivity varies inversely as the logarithm of the average grain size: _iH_c(MA/m)=1.7312-0.48161nd(μm) which confirms the randomness of nucleation of reversed domains and the statistical nature of coercivity,indicating that the decrease of grain size would reduce the average number of de- fects on its surface and lower the probability of magnetization reversal of a grain and the cu- mulative fraction of the grains that have reversed their magnetization.Coercivity is thus en- hanced.
关键词:
Pr-Fe-B magnet
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ZHENG Yangzeng ZHANG Fucheng Yanshan University
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Qinhuangdao
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China
金属学报(英文版)
The heterogeneous distribution of C and metallic alloying elements as well as the phase com- position changes before and after cold deformation of an Fe-Mn-Cr-C alloy have been stu- died by the use of Mssbauer spectroscopy.The austenites without and with C and metallic alloying elements are found in the alloy in as-solid solution state.While the martensites with- out and with C and alloying elements may be induced by cold deformation.The transforma- tion from austenite to martensite in the alloy is confirmed via theoretical computation and ex- periments to be controlled by the number of covalent electron pairs forming covalent bond in austenitic crystal cell of the alloy.The formation of strong covalent bond between C and me- tallic elements can vigorously retard the γ/α' transformation.
关键词:
heterogeneity
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X. Chang
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K. Qin and Y.L.Lu Orthodontic Department of Stomatology College
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China Medical University
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Sheny ang 110001
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China
金属学报(英文版)
proach change of CGRP with time in periodontal ligaments of rats in magnetic field, maxillae of 28 Wistar rats of 6 7 weeks were placed in magnetic fields of permanent magnets Nd 2 Fe 4 B. Changes of CGRP with t ime in maxillary periodontal ligaments of the rats were studied by immunohistochemistry. The result showed that: magnetic field had dynamic effect and some promotional effect on recove?E F F E C T O F M A G N E T I C F I E L D O N C A L C I T O N I N G E N E- R E L A T E D P E P T I D E I N P E R I O D O N T A L L I G A M E N T S O F R A T S X. Chang , K. Qin and Y. L. Lu Orthodontic Department of Stomatology College , China Medical University , Shenyang 110001 , China Manuscript received 24 June 1999 In order to approach change of C G R P with tim e in periodontal liga m ents of rats in m agneticfield , m axillae of 28 Wistar rats of 6 7 weeks w ere placed in m agnetic fields of per m anentm agnets Nd 2 Fe4 B. Changes of C G R P with tim e in m axillary periodontal liga ments of therats were stu died by i m m unohistoche mistry . The result sho wed that : m agnetic field had dy na m ic effect an d so m e pro motional effect on recovering and reconstruction of the periodontaltissues in it . This provided a better theoretical evidence for clinical use of per m anent m agnets .
关键词:
per m anent m agnet Nd 2 Fe4 B
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