热成形B1500HS硼钢与DP780双相钢点焊焊接性及仿真分析

Weldability and Numerical Study of the Resistance Spot Weld of Hot-formed B1500HS Boron Steel and DP780 Dual-phase Steel

以热成形B1500HS钢和DP780双相钢电阻点焊为研究对象,通过对焊点的熔核特征、热影响区微观组织以及焊接缺陷的分析,对焊接接头的焊接性能进行评价。同时,结合Sorpas软件建立点焊数值模型,对点焊过程进行了仿真分析,再现了点焊的熔核形成过程、焊接温度场分布以及焊接后焊点特征。研究表明,板材的接触电阻和焊接电流密度分布影响焊核的形成;热影响区主要由于焊接热循环中峰值温度不同,形成不同的微观组织结构;焊接缺陷的形成主要是由焊接飞溅影响所致。

Based on the resistance spot welding of B1500HS hot-formed steel and DP780 dual-phase steel, the weldability of the welding joints was evaluated by analyzing the weld nugget features, mierostructure of heat affected zone and weld defects, etc. Meanwhile, the numerical model of spot welding was established in combination with a Sorpas software, and the spot weld nugget formation, welding temperature field distribution and characteristics of the joints after welding was reproduced by simulation analysis. The investigation suggested that the contact resistance of the sheet and the welding current density distribution in the welding process affected the weld nugget formation; the difference of HAZ microstructures was mainly infected by the peak temperature in welding thermal cycle; the formation of weld defects was mainly caused by the welding splash.