元素Nb对TiNbV微合金钢CGHAZ组织与冲击韧性影响  

Effect of element Nb on microstructures and impact toughness of CGHAZ in TiNbV micro-alloyed steels

作　　者：闫涵 赵迪[1] 祁同福 冷雪松 付魁军 胡奉雅 YAN Han;ZHAO Di;QI Tongfu;LENG Xuesong;FU Kuijun;HU Fengya(State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,Harbin,150001,China;State Key Laboratory of Metal Materials for Marine Equipment and Application,Iron&Steel Research Institute of Ansteel Group Corporation,Anshan,114009,China;Department of Mechanical Engineering,The University of Sheffield,Sheffield,S102TN,UK)

机构地区：[1]哈尔滨工业大学,先进焊接与连接国家重点试验室,哈尔滨150001 [2]海洋装备用金属材料及其应用国家重点试验室,鞍山114009 [3]谢菲尔德大学机械工程系,谢菲尔德,S102TN UK,英国

出　　处：《焊接学报》2020年第12期33-37,I0003,共6页Transactions of The China Welding Institution

基　　金：国家科技支撑项目(2006BAE03A15);海洋装备用金属材料国家重点实验室开放基金资助项目(SKLMEA-K201702,SKLMEA-K201802).

摘　　要：利用焊接热模拟研究Nb元素含量对TiNbV微合金钢焊接热影响粗晶区(CGHAZ)组织和性能的影响.低铌钢和高铌钢在经历焊接热循环后微观组织构成及晶粒尺寸有显著差异.Nb元素含量为0.005%时焊接CGHAZ组织为铁素体和针状铁素体以及珠光体,大角度晶界和小角度晶界的晶粒比例相当,焊接CGHAZ晶粒尺寸粗大不均匀.随着Nb元素含量的增加,大角度晶界的晶粒数量有所增加,晶粒得到细化.但是,针状铁素体形成受到抑制,CGHAZ中贝氏体含量增加.微合金钢中贝氏体的形成对焊接CGHAZ冲击韧性的下降起主导作用,Nb元素的含量控制在合适范围内(~0.02%),才可以保证CGHAZ具有良好的冲击韧性.The microstructure evolution and impact toughness of the coarse grain heat-affected-zone(CGHAZ)of TiNbV micro-alloyed steel were investigated by the simulated welding thermal cycle.The microstructure and grain size of the simulated CGHAZ between low-niobium steel and highniobium steel is significantly different.When the Nb content is low(0.005%),the CGHAZ consists of ferrite,acicular ferrite,and pearlite.The ratio of the large-angle grain boundary and the small-angle grain boundary is equal,and the grain size of the CGHAZ is coarse and uneven.With the increase of Nb content,the number of grains in the high-angle grain boundary increases,and the grains are refined.However,the formation of acicular ferrite is suppressed,and the bainite content of CGHAZ increases.The formation of bainite in the microalloyed steel plays a leading role in the decrease of the impact toughness of CGHAZ.The content of element Nb should be controlled within an appropriate range(~0.02%)to obtain good impact toughness.

关 键 词：TiNbV微合金钢 焊接热影响粗晶区 Nb元素 微观组织 冲击韧性 

分 类 号：TG421[金属学及工艺—焊接]