CO2 Laser Study of SS316 and Ni201 Dissimilar Metal Joining

Abstract

Dissimilar metal welded joints are commonly used in the nuclear sector to connect pressure vessel ferritic steel pipe nozzles to austenitic stainless steel safe-end pipes. Stainless Steel 316 and Nickel 201 dissimilar joints are focused on by utilising a 4KW CO2 laser welding machine in this study. Mechanical parameters such as ultimate tensile strength (UTS) and hardness survey were used to identify a high-quality welded junction. The tensile stress was found to be 412 Mpa, and the fracture occurred outside the weld zone on the nickel side. The tensile test shows that the weld was strong enough to break through the base metal. The profile of the weld bead is critical to ensure that it is a strong weld junction. Some delta ferrite has been observed in the interdendritic zone in microstructure studies, along with columnar grains during solidification, all of which point to successful fusing in the joint between the two dissimilar metals. With the 4 kW CO2 laser welding machine, it is possible to join materials that are completely different from each other.