电极板辅助点焊钢/铝异质接头的组织与性能  

Microstructure and mechanical property of dissimilar material resistance spot welded joint of steel and aluminum alloy with electrode plate

作　　者：张伟华[1] 孙大千[1] 李志东[2] 刘东阳[1] 李丹丹[1] 

机构地区：[1]吉林大学材料科学与工程学院,长春130022 [2]吉林大学工程训练中心,长春130022

出　　处：《焊接学报》2011年第9期85-88,117,共4页Transactions of The China Welding Institution

基　　金：吉林省科技厅应用基础研究基金资助项目(20100518);吉林大学国家级大学生创新性实验计划项目(2010A43063)

摘　　要：采用电极板辅助点焊进行了H220YD高强钢与6008-T66铝合金异种金属的连接,研究了接头的微观组织和力学性能.结果表明,焊接接头是通过液态铝合金在钢/铝界面处对高强钢的润湿铺展而形成的,本质上属于熔-钎焊接头.钢/铝界面上生成了由Fe2Al5和FeAl3组成的金属间化合物层.接头中铝合金熔核直径在焊接电流为14kA、焊接时间为300 ms时达最大值为9.5 mm.接头拉剪力随焊接电流的增加先迅速增大后趋于稳定,当焊接电流为12 kA、焊接时间为300 ms时达4.3 kN,比不加电极板时提高约30%.在接头拉剪过程中裂纹的扩展路径不仅沿着金属间化合物,还部分经过铝合金熔核内部.Dissimilar materials of H220YD high strength steel and 6008-T66 aluminum alloy had been joined by resistance spot welding with electrode plate.Microstructure and mechanical property of the dissimilar material welded joint were investigated.The results indicated that the welded joint was achieved by means of wetting and spreading of liquid aluminum alloy on solid steel surface,hence it could be regarded as a special welded-brazed joint.A thin dual-layered intermetallic compound layer composed of Fe2Al5 and FeAl3 was formed on the steel/aluminum alloy interface.The diameter of aluminum alloy nugget of the welded joint reached the maximum value of 9.5 mm at welding speed of 14 kA and welding time of 300 ms.With the increase of welding current(8-14 kA),the tensile-shear load of the welded joint increased rapidly first(8-12 kA) and then became calm gradually(12-14 kA).The tensile-shear load was up to 4.3 kN at welding current of 12 kA and welding time of 300 ms,which was about 30% higher than that of the welded joint obtained without electrode plate.During tensile shear testing,the cracking developed through the brittle intermetallic compound layer and partially in the aluminum alloy nugget.

关 键 词：高强钢 铝合金 电阻点焊 电极板 

分 类 号：TG443[金属学及工艺—焊接]