镀锌中锰钢电阻点焊接头裂纹形态及分布  

Morphology and Distribution of Cracks in Galvanized Medium Manganese Steel Resistance Spot Welded Joint

作　　者：孙福文 赵杨洋 王武荣[1] 韦习成[1] SUN Fuwen;ZHAO Yangyang;WANG Wurong;WEI Xicheng(School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学材料科学与工程学院,上海200444

出　　处：《热加工工艺》2023年第17期143-146,共4页Hot Working Technology

基　　金：上海市浦江人才计划资助项目(19PJ1403800)。

摘　　要：采用光学显微镜、扫描电镜附带能谱仪(EDS)、电子背散射衍射仪(EBSD),对镀锌中锰钢电阻点焊接头横截面裂纹的形貌、分布及元素成分进行了研究。结果表明,88.1%的微裂纹分布在压痕台阶处,87.5%的裂纹为深度小于50μm的浅裂纹;裂纹内部充满了锌且裂纹为沿晶裂纹,推断焊点表面裂纹属于液态金属脆化裂纹,点焊过程中镀锌层受热熔化,沿钢材表面晶界渗入并在应力作用下产生沿晶开裂。The morphology,distribution and element composition of cracks in cross-section of resistance spot welding joint of the galvanized medium manganese steel were studied by optical microscope and scanning electron microscopy(SEM)with energy dispersive spectrometer system(EDS) and electron backscattered scattering detection(EBSD).The result show that 88.1% of the cracks are located at the indentation slop,and 87.5%% of the cracks are superficial cracks with a depth of less than 50 μm;zinc accumulation occurs in the cracks,and the cracks are intergranular cracks.It is inferred that the cracks belong to the liquid metal embrittlement crack,as zinc coating is melted and penetrates along the grain boundaries,intergranular crack occurs under stress.

关 键 词：镀锌中锰钢 电阻点焊 液态金属脆化裂纹 

分 类 号：TG453.9[金属学及工艺—焊接]