中文摘要：

进行了2 mm SUS301L-HT不锈钢激光焊和惰性气体保护（MIG）焊试验,对比了两组焊缝在成形、显微组织、力学性能等方面的差别。两种焊接方法焊得的焊缝在成形上有较大不同,激光焊焊缝成形均匀稳定,接头角变形小,熔宽小,热影响区（HAZ）窄,优于MIG焊缝。两种焊接方法焊得的焊缝的金相组织差异较大,激光焊焊缝组织由细小柱状奥氏体枝晶和枝晶间δ铁素体组成,HAZ发生了回复和再结晶,晶粒有一定程度的长大;MIG焊缝由粗大的块状奥氏体组织和少量δ铁素体组成,HAZ组织变化丰富,组织随着与熔合线距离的改变而不同。两种焊接方法焊得的焊缝的力学性能差异明显,激光焊焊缝拉伸性能优于MIG焊缝,激光焊接头拉伸断裂在焊缝,断口为典型韧性断口,接头抗拉强度达到979.1 MPa,延伸率达到48.2%。

英文摘要：

Fiber laser welding and metal-inert gas（MIG） welding of SUS301L-HT sheets with 2 mm thickness are carried out, and differences in welding formation, microstructure and mechanical properties between two types of joints are researched and compared. Welding formation of two types joints is different from each other, and formation of laser welding joint is better than that of MIG welding joint. Stable and uniform welding formation is acquired in fiber laser welding process and almost no angular distortion is found in laser welding joint and width of beads and heat affected zone（HAZ） is narrow. Microstructure of laser welding joints is quite different from that of MIG welding joint. Microstructure of laser welding bead consists of fine columnar austenitic dendritic crystals and interdendritic δ ferrite, and size of grain grows a little in HAZ; phase composition of MIG welding bead contains massive austenitic and a little δ ferrite, and microstructure in HAZ gets different obviously as distance from fusion line changes. Mechanical properties of two types joints are different. Tensile property of laser welding joint is much better than that of MIG welding joint. Tensile sample of laser welding joint breaks at bead, in tensile experiment,in a classical ductile way, ductility of the joint is up to 48.2%, and tensile strength is up to 979.1 MPa.