双相钢马氏体含量对点焊极值电流与熔核转变规律的影响  

The influence of martensite content on the limit of spot welding current and the law of nugget microstructure transformation

作　　者：吕冬[1] 刘仁东[1] 芦延鹏 苏红英[1] 陆晓峰[1] Lu Dong;Liu Rendong;Lu Yanpeng;Su Hongying;Lu Xiaofeng(Angang Steel Company Limited,Liaoning,Anshan 114009,China)

机构地区：[1]鞍钢股份有限公司,辽宁鞍山114009

出　　处：《焊接》2020年第1期36-41,I0020,共7页Welding & Joining

摘　　要：采用中频逆变点焊机对1.2 mm厚不同马氏体含量的双相钢进行焊接,建立了点焊工艺窗口,分析了马氏体含量对焊接工艺和熔核组织的影响规律。分别采用光学显微镜、透射电子显微镜和维氏硬度计对焊点熔核区组织、显微硬度进行分析。结果表明,随着钢中马氏体含量的增加,工艺窗口向电流减小的方向偏移,Imin随马氏体含量的增加小幅度的减小,Imax大幅度的降低;熔核区组织为完全马氏体组织,随钢中马氏体含量的增加组织由板条马氏体转变为板条马氏体+孪晶马氏体组织,HAZ区硬度逐渐显示出软化特征。In this paper,1.2 mm dual-phase steel with different martensite content was welded with intermediate frequency inverter spot welder and welding process window was established,the influence of martensite content on welding process window was analyzed.The microstructure and microhardness of nugget were researched by OM,TEM and Vickers hardness tester.The results show that with the increase of the martensite content the welding process window is offset in the direction of current reduction,and Imin decreases by a small amount with the increase of martensite content,however Imax decreases a lot.The microstructure of the nugget is totally martensite.The microstructure changes from lath martensite to lath martensite plus twinned martensite with the increase of martensite content,Hardness in HAZ area gradually shows softening characteristics.

关 键 词：电阻焊 点焊 马氏体 工艺窗口 组织 

分 类 号：TG406[金属学及工艺—焊接]