高强钢与铝合金电阻点焊性能

Properties of resistance spot weld between high strength steel and aluminum alloy

针对高强钢DP590和铝合金Al6061利用电阻点焊专业有限元软件SORPAS进行模拟分析,分析了钢-铝点焊熔核形成过程的三个阶段,阐述了钢-铝电阻点焊的非对称温度场分布特点及由此产生的熔核偏移和双熔核特征;通过EDS等检测手段结合宏微观金相组织及试验过程中实测的焊接区动态电阻,揭示出点焊接头形成过程即熔融成液态的铝合金在钢-铝界面处向高强钢润湿铺展并扩散而形成熔-钎焊接头;焊接过程中铝原子扩散到钢中的原子分数达到40%左右,形成钢铝晶间化合物的厚度小于2μm.

Numerical simulation of resistance spot welding of high strength DP590 steel and 6061 aluminum alloy was carried out by finite element method( FEM) software SORPAS.Three stages of nugget formation process of steel-aluminum RSW had been analyzed. Meanwhile,the nugget offset phenomenon and dual nugget characteristics caused by asymmetric temperature distribution field feature of steel-aluminum RSW had been elaborated. The macro and micro structure of the weld was examined with EDS,and the dynamic resistance of the welded zone was measured. The results revealed that the melted aluminum alloy spread and diffused on the interface between the steel and aluminum,which led to the formation of fusion-brazed joint. The thickness of intermetallic compound( IMC) is less than 2 μm while the atomic percentage of aluminum diffused in steel are about 40%.