超细晶粒钢激光焊接接头的组织性能研究

Microstructure and Mechanical Properties of Laser Welded Super-fine Grain Steel

研究经过度变形得到的超细晶粒钢 Q2 3 5的激光焊接特性。结果表明超细晶粒钢在激光焊时会因形变晶粒发生再结晶而在接头中出现软化区 ,区域大小受焊接工艺参数的影响 ,高激光功率和高焊接速度可以产生很窄的再结晶区 ,从而使接头强度高于母材。

In this paper,the weldability of laser beam welding of super-fine grain steel,which is made by extra deformation,has been investigated.The experimental results show that the laser-welded joint has a softened zone,which is the result of re-crystallization of the deformed grain.Higher laser power and higher welding speed,which results in lower heat input,will give more anrrow softened zone,thereby leads on higher yield strength.Lower laser power and lower welding speed will make the joint fracture in the recrystallization zone,whereas higher power and higher welding speed makes the joint break at base metal.The SEM photo of the fissure surface shows that the fracture of the joint belongs to ductile fracture.