GAO Hua XUE Lijue Shanghai University of Engineering Science
,
Shanghai
,
China Associate Professor
,
Dept.of Materials
,
Shanghai University of Engineering Science
,
350 Xianxia Road
,
Shanghai
,
China
金属学报(英文版)
Hydrogen induced cracking(HIC)of 0.3% C,1% Cr,1% Mn,1% Si high strength steel has been studied under simple mode Ⅰ,mode Ⅱ and(Ⅰ+Ⅱ)mixed mode loading conditions.Af- ter being hydrogen-charged in IN H_2SO_4 solution,the material behaved hydrogen embrittlement in all the cases studied.The threshold K_(ⅡH)/K_(ⅡX) of HIC under mode Ⅱ load- ing was 0.27,which was nearly the same as that K(ⅠH)/K_(ⅠX)=0.29 under mode Ⅰ loading. While the thresholds of-HIC under(Ⅰ+Ⅱ)mixed mode loading were 0.36,0.41 and 0.37 cor- responding to the K_Ⅱ/K_Ⅰ ratio of 0.27,0.4 and O.81.The results show that simple mode Ⅰ or mode Ⅱ loading is more susceptible to hydrogen embrittlement than(Ⅰ+Ⅱ)mixed mode. For explaining the experimental results,the effects of triaxial stress as well as plastic deformation ahead of crack tip has been discussed.
关键词:
(Ⅰ+Ⅱ)mixed mode
,
null
GAO Hua CHEN Youxuan LI Ming Shanghai University of Engineering Science
,
Shanghai
,
ChinaCHEN Dehai Shanghai Dalong Machinery
,
Shanghai
,
China Associate Professor
,
Dept.of Materials
,
Shanghai University of Engineering Science
,
Shanghai 200051
,
China
金属学报(英文版)
The effect of proportional and non-proportional overloading on mode l fatigue crack growth have been studied,and the influences of crack tip plastic zone,crack tip blunting as well as crack closure were discussed.Proportional(model I)overloading may cause more serious crack growth retardation than non-proportional(mixed mode)overloading.Therefore,for estimating the fatigue life of engineering structures to simplify a real overload which may of- ten be non-proportional as a proportional one is not always safe.
关键词:
non-proportional overloading
,
null
,
null
HAN Qiyong YANG Ping SONG Weixi University of Science and Technolonology Beijing
,
Beijing
,
China Division of Metallography
,
Dept.of Materials
,
University of Science and Technology Beijing
,
Beijing
,
China
金属学报(英文版)
The distribution of subversive element sulfur in high temperature phases during solidification of cast iron was investigated by means of liquid quenching method and autoradiography.The results show that in grey cast iron,sulfur is concentrated in the liquid,flake graphite and in the peripherial area of D-type supercooled graphite eutectic cells,but less sulfur is in austenite. Besides,the content of sulfur in A-type graphite is higher than that in D-type graphite,and sulfur content in eutectic austenite is a little higher than that in primary austenite.While,in nodular graphite cast iron less sulfur is in liquid and austenite,but more in nodular graphite. The blackness of the spots on the emulsion film corresponds to the atomic percentage of radioactive substances located on the surface of the specimen.
关键词:
cast iron
,
null
,
null
,
null
