Experimental Investigation of Temperature Field, Fusion Zone Microstructure and Mechanical Properties During Dissimilar Laser Welding of Nickel-Base Alloy and Duplex Stainless Steel

Abstract

The current study delves into the dissimilar laser welding of nickel-base alloy and duplex stainless steel, specifically in circular and plate forms, using fiber laser technology. The study utilizes a design of experiments methodology, specifically employing a central composite design, to methodically evaluate how different laser welding parameters affect the properties of dissimilar welds. The methodology is the response surface methodology (RSM), allowing for a comprehensive evaluation of the effects. The study examines the influence of key welding parameters, such as laser power, welding speed, focal distance, and laser beam deviation from the joint’s center, on several response variables. These variables encompass the depth of the molten pool, the weld microstructure, and its mechanical characteristics. The depth of the molten pool, on the other hand, is primarily influenced by laser power and focal distance. Notably, a transition in microstructure is observed from columnar dendrites to a cellular configuration as one moves from the fusion line towards the center of the fusion zone. In the fusion zone of the duplex base metal, an unmixed zone is identifiable in the upper segments of the fusion line. This phenomenon arises due to incomplete melting at the fusion line.