DH780高强钢双脉冲点焊接头组织性能研究  

Study on Microstructure and Mechanical Properties of Double-pulse Resistance Spot Welded DH780

作　　者：潘进 马成 佘亚东 邢承亮 牛月鹏 曹宏玮 孙力 PAN Jin;MA Cheng;SHE Yadong;XING Chengliang;NIU Yuepeng;CAO Hongwei;SUN Li(Materials Technology Research Institute,HBIS Group,Shijiazhuang 050023,China;HanSteel,HBIS Group,Handan 056015,China)

机构地区：[1]河钢集团材料技术研究院,河北石家庄050023 [2]河钢集团邯钢公司,河北邯郸056015

出　　处：《热加工工艺》2025年第3期45-50,共6页Hot Working Technology

基　　金：河北省高端钢铁冶金联合基金项目(E2019318022);河钢集团重点科技项目(HG2019214)。

摘　　要：针对新研发的DH780增强成形双相钢,进行了电阻点焊工艺开发。采用双脉冲模式在3个焊接时间下分别确定最大、最小焊接电流,获得焊接工艺窗口,并对焊接工艺窗口关键工艺点的接头进行金相分析、硬度检测、拉剪和十字拉伸试验。结果表明:焊接接头中熔核区域经历熔化及快速冷却转变为马氏体,热影响区可划分为3个区域,分别为具有粗大板条马氏体的粗晶区、具有细小马氏体的细晶区以及具有马氏体和铁素体混合组织的部分相变区,其硬度随距熔核的距离增加呈先升高后降低的趋势,并在细晶区达到最大值。焊接工艺窗口左侧边界的拉剪力明显小于右侧边界的拉剪力,各工艺点的十字拉伸力相近,同时各工艺点的拉剪力远大于其十字拉伸力。The resistance spot welding process of the recently developed DH780 dual phase steel with improved formability was studied.The welding process window was obtained by determining the maximum and minimum currents under double-pulse current with three different welding times.The microstructure analysis,hardness test,tensile shear test and cross tensile test were carried out for the spots corresponding to the key process points of the welding process window.The results show that the weld nugget zone experiences melting and rapid cooling and it is transformed into martensite structure.The heat affect zone can be divided into three zones,namely coarse grain zone with coarse martensite structure,fine grain zone with fine martensite structure and partial phase transformation zone with a mixed structure of martensite and ferrite.The hardness of the heat affected zone first increases and then decreases from the nugget side to the base metal side,and it reaches the maximum value in the fine grain zone.The tensile shear force at the left boundary of the welding window is significantly smaller than that at the right boundary.The cross tensile force is similar at different process points.The tensile shear force is significantly higher than the cross tensile force.

关 键 词：电阻点焊 DH780钢 焊接工艺窗口 力学性能 

分 类 号：TG453.9[金属学及工艺—焊接]