TRIP590/CP780异种钢电阻点焊接头组织与性能研究  

Microstructure and properties of resistance spot welding joints of TRIP590/CP780 dissimilar steel

作　　者：朱晓欧 刘占起 尹桂丽[1] 周岐[1] 李楠 ZHU Xiaoou;LIU Zhanqi;YIN Guili;ZHOU Qi;LI Nan(College of Materials Science and Engineering,Liaoning University of Technology,Jinzhou 121001,China;Jinzhou Meilianqiao Auto Parts Co.Ltd.,Jinzhou 121001,China)

机构地区：[1]辽宁工业大学材料科学与工程学院,辽宁锦州121001 [2]锦州美联桥汽车部件有限公司,辽宁锦州121001

出　　处：《兵器材料科学与工程》2023年第4期40-45,共6页Ordnance Material Science and Engineering

基　　金：辽宁省教育厅科学研究项目(LJKMZ20220960);辽宁工业大学博士科研启动基金项目(XB2021005)。

摘　　要：对1 mm厚汽车用TRIP590和CP780异种高强钢板进行电阻点焊试验,研究TRIP590/CP780异种钢电阻点焊接头的显微组织和力学性能,分析了焊接电流对异种钢焊接接头组织与性能的影响。在焊接时间为0.4 s,电极压力为2 kN,电流为6~11 kA时,接头成型良好,内部无熔核偏移、缩孔等缺陷,熔核区组织以板条马氏体为主。当电流为6、9 kA时,两侧热影响区均以回火马氏体和少量铁素体为主,晶粒尺寸分别为1~4μm、2~6μm;当电流为11 kA时,两侧热影响区均以板条马氏体为主,晶粒尺寸为8~15μm。熔核区硬度、CP780侧热影响区软化程度、接头最大拉伸剪切力均随电流的增大而增大。当电流为6、9、11 kA时,接头拉伸断裂分别在熔核区结合面、TRIP590母材、TRIP590侧熔核区。综合分析,当电流为9 kA时,TRIP590/CP780异种钢电阻点焊接头具有较好的力学性能。Resistance spot welding experiments of were carried out on TRIP590 and CP780 dissimilar high strength steel plates with 1mm thickness for automobile.The microstructure and mechanical properties of TRIP590/CP780 dissimilar steel welded joint were studied and the effects of welding current on the microstructure and properties of the dissimilar steel resistance spot welding joint were analyzed.At a welding time of 0.4 s,the electrode pressure is 2 kN,the joint is well formed and there are no defects such as nugget offset and shrinkage cavity in the joint when the welding current is in the range of 6‐11 kA.The microstructure of nugget zone in spot welding joint is mainly lath martensite.When the current is 6 kA and 9 kA,both sides of the heat affected zone are dominated by tempered martensite and a small amount of ferrite,grain size is within the range of 1‐4μm and 2‐6μm respectively;When the current is 11 kA,the lath martensite is dominant in both heat affected zones,and the grain size is within the range of 8‐15μm.The average hardness in nugget zone,the degree of softening in heat affected zone and the maximum tensile shear force of the joint are increased with the increase of welding current.When the current is 6 kA,9 kA and 11 kA,the tensile fracture of the welded joint is located at the joint surface of nugget zone,near the nugget zone of TRIP590 parent metal and TRIP590 side,respectively.On the whole,when the current is 9 kA,TRIP590/CP780 dissimilar steel resistance spot welding joint has good mechanical properties.

关 键 词：CP780钢 TRIP590钢 异种钢焊接 显微组织 电阻点焊 力学性能 

分 类 号：TG456.7[金属学及工艺—焊接]