Microstructure and mechanical properties of CuCrZr/316LN laser welding joints

In this paper, the laser butt welding experiment of CuCrZr and 316LN dissimilar material alloy tube was carried out, and the joint morphology, microstructure, chemical composition and mechanical properties of each sample were observed and analyzed. The experimental results show that the weld is in good shape under the laser power of 1100 − 1400 W, the defocus amount of + 20 mm, the welding speed of 14.5 mm/s and shielded by Ar gas of 15 L/min, which can realize all-position welding of CuCrZr/316LN tube with less internal defects. However, the phenomenon of weld collapse is obvious with the increase of welding power. The transition of the interface elements between the CuCrZr/316LN weld and the base metal is obvious, and there is mainly Fe-rich Fe/Cu solid solution in the weld due to the mutual solubility of Fe and Cu. The tensile strength of the laser welded joint of CuCrZr/316LN tube is higher, the main fracture location is the heat affected zone of copper with coarse grain, the fracture form is mainly ductile fracture.