690MPa级HSLA钢焊缝金属的显微组织与冲击韧性  

Microstructure and impact property of 690 MPa level HSLA steel weld

作　　者：王爱华[1,2] 彭云[2] 肖红军[2] 田志凌[2] 王晶[1] 

机构地区：[1]承德石油高等专科学校,承德067000 [2]钢铁研究总院先进钢铁流程及材料国家重点实验室,北京100081

出　　处：《焊接学报》2013年第4期7-10,42,共5页Transactions of The China Welding Institution

基　　金：国家973重点基础研究发展计划资助项目(2010CB630800)

摘　　要：对690 MPa级HSLA钢的焊缝金属进行了研究,应用OM,TEM,EBSD和Lepera腐蚀法,对焊缝金属的组织、M-A组元、残余奥氏体及晶界角度特征进行了观察,并对焊缝金属的冲击韧性进行了研究.结果表明,采用手工电弧焊焊条和MIG焊丝施焊,焊缝金属在-50℃的平均冲击吸收功分别为31 J和96 J,手工电弧焊焊条施焊的焊缝金属冲击吸收功较低.手弧焊焊条和MIG焊丝施焊的焊缝金属中M-A组元体积分数分别为4.4%和2.52%,M-A组元体积分数的增加是导致手工电弧焊焊条施焊的焊缝金属韧性下降的原因之一,同时手弧焊条焊缝金属中残余奥氏体含量和大角度晶界数量的减少也是导致其韧性降低的原因.The weld metal of 690 MPa level high strength low alloy (HSLA) steel was investigated in this paper. The M-A constituents were etched with Lepera reagent, and the microstructure, residual austenite and grain boundary in the welded metal were observed with optical microscope (OM), transmission electron microscope (TEM) and eletron backscattering diffraction (EBSD), and the impact property was tested. The results reveal that the average Charpy impact values of welded metals made with shielded metal arc welding process and metal inert gas (MIG) welding process were 31 J and 98 J at -50 ℃ respectively. The volume fractions of M-A constituents in welded metals made with shielded metal arc welding and MIG welding processes were 4.4% and 2.52%, respectively. The increase of volume fraction of M-A constituents resulted in the deterioration of impact property of welded metal with shielded metal arc welding, and the decrease of residual austenite and large grain boundary in the welded metal also led to the degradation of impact property.

关 键 词：冲击韧性 化学成分 M-A组元 残余奥氏体 大角度晶界 

分 类 号：TG442[金属学及工艺—焊接]