两种规格超细晶粒钢的激光焊接

超细晶粒钢依靠微米级或亚微米级的铁素体，使钢的强度和韧性大大提高。本文分析了超细晶粒钢的焊接性及激光焊接的特点，进行了超细晶粒钢的激光焊接试验，并与等离子弧焊接、MAG焊接进行了比较，超细晶粒钢激光焊接接头粗晶区有较好的韧性，采用较小的激光功率并配合较慢的焊接速度，可减小粗晶区硬化倾向。终轧温度较高的SS400钢激光焊接接头强度高于母材，深度轧制钢激光焊接接头出现再结晶软化区，当软化区宽度较窄时，不影响整体接头强度，SS400钢和深度轧制钢激光焊接接头均有好的弯曲塑性。

Laser Welding of Two Super-fine Grain Steels

The strength and toughness of super fine grain steels are greatly increased because of its micrometer or sub micrometer grade grain size. In this paper the weldability of super fine gum steels and characteristics of laser welding are discussed, the experiments of laser welding of super fine grain steels are carried out,and the results of laser welding are compared with those of MAG welding and plasma arc welding. The coarse grain zones of laser welded joint of super fine grain steel show good toughness. The hardening tendency of coarse grain zones is reduced if a low laser power and a slow welding speed are adopted. The tensile strength of laser welded joint of SS400 steel,which was rolled at higher temperature,is higher than that of parent metal. The welded joint of deeply rolled steel,which was work hardened, has softening zones of recrystallization.The tensile strength of the joint is not affected if the softening zones are narrow. The laser welded joints of both SS400 steel and work hardeened steel have good bending ductility.