热循环方式对Q690TMCP钢粗晶区组织和性能的影响

Effects of weld thermal cycle modes on microstructure and properties of coarse- grained heat- affected zone of Q690 steel processed by TMCP

对比了两种热循环(实际焊接与模拟单道次焊接)对Q690 TMCP钢粗晶区组织性能的影响。结果表明:模拟焊接热循环条件下,随热输入增大粗晶区组织分别经历了板条马氏体、回火马氏体、上贝氏体及粒状贝氏体转变,粗晶区冲击功随热输入能量的增大先增大后减小,峰值对应热输入20 kJ·cm-1;相同热输入能量的实际焊接试样粗晶区的冲击功变化趋势与模拟焊接试样相似,但数值均低。分析得出,实际焊接试样粗晶区中新生M-A组元导致了其冲击功相对更低。

Effects of two different thermal cycles（ real welding and single pass simulated welding） on microstructure and properties of a TMCP Q690 steel were studied. The results indicate that by increasing heat input the microstructure of the simulated coarse-grained heat- affected zone （CGHAZ） undergoes transformation of lath martensite, tempered martensite, upper bainite and granular bainite successively, its charpy impact energy increases first and then decreases with the corresponding heat input peak of 20 kJ cm-1. The variation trend of charpy impact energy in the real CGHAZ shows good similarity to that of simulated CGHAZ. Additionally, the lower value of charpy impact energy observed in the real CGHAZ is due to the formation of martensite-austenite constituent.