为了满足工业生产中提出的结构轻量化要求, 采用IPG光纤激光器对薄板T型接头进行了激光穿透焊试验, 通过改变激光穿透焊工艺参数, 研究不同热输入对焊接接头显微组织及接头尺寸变形量的影响, 并对接头显微硬度进行了测试和分析。结果表明, 随着热输入的增加, 焊缝熔深增大, 焊缝及热影响区晶粒尺寸增加, 焊缝内马氏体的含量减少, 焊缝及热影响区内显微硬度呈下降趋势; 焊缝组织为马氏体和上贝氏体, 粗晶区为贝氏体和少量马氏体, 细晶区为粒状贝氏体和珠光体; 焊缝及热影响区的显微硬度值均高于母材。

To satisfy the requirements of structure lightweight in industrial production,thelaser penetration welding test forthin T-jointis conducted by using the IPG fiber laser.The microstructure andthe deformation of the welded joints under different heat input is researched by changing the laser welding process parameters. Also, the microhardness of the welded joints was tested and analyzed. The results show that with the increase oflaser welding heat input, the weld penetration increases. Meanwhile, the grain size of weld and heat affected zone (HAZ) increases. However, the content of martensitein weld seam decrease and the microhardness of weld seam and HAZ decreases. The weld microstructure is marten site and upper-bainite, and the coarse grained region is bainite and martensite, while the fine grained region is granular bainite and pearlite. The micro hardness of weld seam and HAZ is higher than that of base metal.