汽车用DP800双相钢点焊工艺窗口和接头性能

开展2.0 mm厚DP800双相钢的电阻点焊试验,测试DP800双相钢点焊工艺窗口,研究焊接电流、焊接时间、电极压力对焊点拉剪力的影响规律,并观察接头不同区域的微观组织。结果表明,DP800高强钢焊接性较好,点焊工艺窗口满足工业应用要求;随着焊接电流和焊接时间的增加,焊点直径和拉剪力先增加后趋于平稳;随着电极压力的增加,点焊直径和拉剪力先增加后减小;焊点热影响晶粒细小,由马氏体组织构成;焊核为典型的柱状晶,显微组织为马氏体和少量的贝氏体。

Spot welding parameter window and joint properties of automotive DP800 dual-phase steel

The resistance spot welding test of 2 mm thick DP800 dual phase steel was carried out.Spot welding parameter window of DP800 dual-phase steel was measured.The influence rule of welding current,welding time and electrode pressure on the tensile and shearing force of solder joints was studied,and the microstructure of different regions of joints was observed.The results show that the weldability of DP800 high strength steel is good,and the spot welding process window meets the requirements of industrial application.With the increase of welding current and welding time,the diameter and tensile strength of welding spot first increase and then become stable.With the increase of electrode pressure,the spot welding diameter and the tensile shear force firstly increase and then decrease;the heat affected grain size of the weld spot is small and consist of martensite structure;the weld core is a typical columnar crystal,the microstructure is martensite and a small amount of bainite.