中锰汽车钢激光焊接接头组织与杯突成形性能研究

Microstructure and Formability of Laser Welded Joint in Medium Mn Automobile Steel

中锰钢具有良好的高强度与高塑性综合性能,在汽车工业中受到广泛关注,成为新一代汽车用钢热门材料之一。采用光纤激光器对Fe-0.1C-5Mn中锰钢进行焊接,对焊接接头进行埃里克森杯突成形试验,结合有限元模拟分析了接头杯突成形性能影响因素,并与钨极氩弧焊试验结果进行对比。研究结果表明,中锰钢激光焊接后接头形成“硬化区”,降低焊接接头的成形性能。影响中锰钢焊接接头成形性能的主要因素是接头硬化区宽度,硬化区宽度越窄,焊接试板成形性能越好。激光焊接速度对硬化区宽度的影响更为明显,提高焊接速度,能够通过降低硬化区的宽度提高焊接接头成形性能。试验条件下,2 mm厚的中锰钢激光焊接试板成形比能够达到0.66。

The medium-Mn steel(0.1%C-5%Mn-Fe),renowned for its exceptional balance of high strength and ductility,has garnered significant attention in the automotive industry as a promising material for next-generation automotive steel.The medium-Mn steel was joined with fiber laser,and formability of the welded joint was carried out with the Erickson cupping test machine.The factors affecting the cupping test performance of the joint were analyzed with finite element simulation,and the cupping test results were compared with those of gas tungsten arc welding.The results show that"hardening zone"is formed in welded joint,which reduces the formability of the welded joint.The width of the HZ is one of the primary factors affecting the formability of the welded joint,and the narrower the hardening zone is,the better the formability of the welded joint is.The effect of laser welding speed on the width of hardening zone is more obvious,and the formability of welded joint can be improved by reducing the width of hardening zone.In this paper,the forming ratio of laser welded joint of 2 mm thick medium Mn steel can reach 0.66.