Effect of Heat Input on Cleavage Crack Initiation of Simulated Coarse Grain Heat-affected Zone in Microalloyed Offshore Platform Steel  

作　　者：Feng LU Guang-ping CHENG Feng CHAI Tao PAN Zhong-ran SHI Hang SU Cai-fu YANG 

机构地区：[1]School of Material Science and Engineering,Anhui University of Technology [2]Department of Structural Steel,Central Iron and Steel Research Institute

出　　处：《Journal of Iron and Steel Research International》2016年第10期1086-1095,共10页

基　　金：Item Sponsored by Vanitec-CISRI Vanadium Technology Center

摘　　要：The combined effects of martensite-austenite（MA）constituent and pearlite colony on cleavage crack initiation in the simulated coarse-grained heat-affected zone（CGHAZ）of V-N-Ti microalloyed offshore platform steel under different heat inputs were investigated.The results of welding simulation,instrumented impact test,and quantitative analysis indicated that the size of the MA constituent decreased with the increase in cooling time,and by contrast,the size of the pearlite colony increased.According to Griffith theory,the critical sizes of cleavage microcracks were calculated.With the increase of cooling time,the calculated microcrack size could be characterized by the size of the MA constituent first,and then fitted with the size of the pearlite colony.Moreover,the calculated microcrack size variation was opposite to the microcrack initiation energy.This phenomenon is probably due to the combined effects of the MA constituent and pearlite colony with increasing the cooling time of the specimen′s temperature from800 to 500 ℃.The combined effects of martensite-austenite（MA）constituent and pearlite colony on cleavage crack initiation in the simulated coarse-grained heat-affected zone（CGHAZ）of V-N-Ti microalloyed offshore platform steel under different heat inputs were investigated.The results of welding simulation,instrumented impact test,and quantitative analysis indicated that the size of the MA constituent decreased with the increase in cooling time,and by contrast,the size of the pearlite colony increased.According to Griffith theory,the critical sizes of cleavage microcracks were calculated.With the increase of cooling time,the calculated microcrack size could be characterized by the size of the MA constituent first,and then fitted with the size of the pearlite colony.Moreover,the calculated microcrack size variation was opposite to the microcrack initiation energy.This phenomenon is probably due to the combined effects of the MA constituent and pearlite colony with increasing the cooling time of the specimen′s temperature from800 to 500 ℃.

关 键 词：simulated coarse-grained heat-affected zone martensite-austenite constituent pearlite colony cleavage fracture V-N-Ti microaltoying 

分 类 号：TG457.11[金属学及工艺—焊接]