热成形钢板与双相钢板焊点失效模式研究  

Research on Failure Mode of Welding Spots between Hot-formed Steel Sheet and Dual-phase Steel Sheet

作　　者：聂昕[1] 陈焕焕 NIE Xin;CHEN Huanhuan(State Key Laboratory of Advanced Design and Manufacture for Vehicle Body,Hunan University,Changsha,410082)

机构地区：[1]湖南大学汽车车身先进设计制造国家重点实验室

出　　处：《中国机械工程》2019年第21期2636-2642,共7页China Mechanical Engineering

基　　金：国家自然科学基金资助重点项目(61232014);柳州市科技计划重大专项(柳科攻2018AA20503);汽车用钢开发与应用技术国家重点实验室开放基金资助项目

摘　　要：针对热成形钢板与双相钢板的焊点失效模式,采用试验+模拟的方法进行研究。通过数值模拟得到了合适的焊接工艺窗口,在此基础上研究了焊接时间、熔核偏移等对焊点力学性能的影响。拉剪试验结果表明:随着焊接时间的延长,焊点失效模式由界面断裂向熔核拔出转变。研究失效模式发现,熔核偏移对熔核拔出失效部位影响极大,即薄板与厚板焊接时,熔核更容易从薄板拔出;板厚相同时,熔核更容易从热成形钢侧拔出。最后结合试验数据建立了焊点力学模型,得到热成形钢板和双相钢板焊点失效准则。The failure mode of welding spots between hot-formed steel sheet and dual-phase steel sheet was studied by tests and numerical simulations,finite element(FE)model was built to simulate the resistance spot welding(RSW)process.So as the welding lobe got,the effects of welding time and positive deviation of fusion zone(FZ)on mechanics properties of welding spots were researched.As the tensile-shear test shown,with the increase of welding time,the failure mode of welding spots transited from interface fracture(IF)to pullout failure(PF).At the same time,it is found that the positive deviation of FZ has a great influence on starting positions of PF.when the thin sheet welded with thick sheet,the welding spots were easier to be pulled out from the thin sheet sides,when the sheet thickness is the same,the welding spots were easier to be pulled out from the hot-formed steel sides.Finally,the welding spot mechanics model was established based on experimental data,the welding spot failure criteria was obtained.

关 键 词：焊接时间 拉剪强度 硬度分布 焊点失效准则 

分 类 号：TG453.9[金属学及工艺—焊接]