Effect of laser welding parameters on the temperature distribution, microstructure and mechanical properties of dissimilar weld joint of Inconel 625 and stainless steel 304

Abstract

Laser welding technology and investigation of temperature distribution can serve as an important criterion for performing high-quality joints. In this experimental study, dissimilar laser welding is performed between stainless steel 304 (S.S 304) and Inconel 625 alloys. The temperature is measured by changing such parameters of laser as laser power, welding speed and nozzle distance. The parameters variations are 300-400 W, 240-480 mm/min and 0-4 mm for the laser power, welding speed and nozzle distance, respectively. Examining the parameters shows that the change in the laser power due to temperature changes had a greater effect on temperature changes around the Inconel 625 side melt pool; also, the rate of change was about twice that of S.S 304. In the case of the S.S 304 alloy, the temperature increase was occurred at a slower rate and the evaporation rate of the material on the S.S304 side is higher than that of Inconel 625 superalloy. As a result, the rate of temperature increase is slower and part of the laser energy is used to evaporate S.S 304. The microstructural changes in the boundary of the fusion zone with the base metal Inconel 625 are clearly visible.