铝/钢异种金属电阻点焊接头微观组织与力学性能研究

Study on Microstructure and Properties of Resistance Spot Welded Joints of Al/Steel Dissimilar Metal

采用电阻点焊实现对6061铝合金和H220YD高强镀锌钢的焊接,通过金相显微镜、扫描电镜、能谱仪、显微硬度计和万能试验机等测试方法研究了铝/钢点焊接头的组织和性能。结果表明,铝/钢点焊接头从铝侧向钢侧依次为铝合金熔核、铝/钢界面、高强钢热影响区。铝/钢点焊接头界面靠近钢侧金属间化合物层显微硬度最高,靠近铝合金侧金属间化合物硬度次之,铝合金显微硬度最低。随着焊接电流的增加,铝/钢点焊接头拉剪力先增加后减小,焊接电流9 k A、焊接时间300 ms、焊接压力2 k N时,接头拉剪力达到最大值3.4 k N。

6061 Al alloy and H220YD high strength steel were welded by resistance spot welding. The microstructure and properties of Al/steel welded joints were studied by metallographic microscope, SEM, EDS, microhardness and universal testing machine. The results show that aluminum from aluminum/steel spot-welded joint lateral steel side is composed of nuclear for aluminum alloy, aluminum/steel interface and the identity of heat affected zone. The intermetallic layer near the steel side has the highest microhardness, and the microhardness of Al alloy is lowest. With the increase of welding current, the tensile-shear force of aluminum/steel spot-welded joint increases first and then decreases, when the welding current is 9 kA, welding time is 300 ms, and the welding pressure is 2 kN, the force value of the welded joint obtains the highest of 3.4 kN.