Abstract: With the higher requirement of automobile lightweight and safety, more and more hot stamping parts be used in body in white because of their very high strength. For hot stamping parts, the strength of heat-affected zone (HAZ) will be lower after resistance spot welding due to insufficient cooling. The small heat affected zone will cause stress concentration. In the pole crash testing, the hot stamping A-pillar reinforcement is easy to crack from the heat affected zone. In order to solve the crack issue, the A-pillar reinforcement can adopt the external induction annealing. After the induction annealing, the strength of welded flange is the same as that of heat affected zone, so as to eliminate the problem of stress concentration in heat affected zone. The results of computer aided engineering analysis show that the problem of collision cracking can be solved by induction heating without increasing the thickness and weight of parts.

Key words: Hot stamping parts; Resistance spot welding; Induction annealing

摘要： 随着汽车轻量化和碰撞安全要求的提高，热成型零件由于具有极高的强度，在车身中 的应用越来越多。但是热成型零件进行电阻点焊后，焊点周围热影响区由于冷却不足，导致 强度急剧降低，形成应力集中。如采用热成型的 A 柱上加强板在柱碰过程中，很容易从焊点 热影响区处撕裂。为了解决碰撞撕裂问题，论文采用模具外感应退火，可以使焊接法兰的强 度与热影响区强度相同，从而消除热成型零件电阻点焊带来的热影响区应力集中的问题。计 算机辅助工程分析结果表明，采用感应加热可以在不增加零件厚度和重量的情况下解决碰撞 开裂问题。

关键词: 热成型零件；电阻点焊；感应退火