Experimental investigation on laser beam welding of martensitic stainless steels in a constrained overlap joint configuration

This paper presents experimental investigation of laser beam welding of martensitic stainless steels in a constrained overlap configuration. Experimental studies were focused on the effects of laser power, welding speed and fiber diameter on bead geometry and mechanical properties of the weld. Metallurgical study of a selected welded joint was done only to show various microstructures typically formed at different zones. Laser power and welding speed were found the most significant factors affecting the weld geometry and shearing force. The contour plots showing constant response lines indicated the evidence of two-factor interaction effects of laser power-welding speed, welding speed-fiber diameter, and fiber diameter-laser power on all the responses except the weld width. Moreover, energy density plots illustrated its linear relationship with penetration depth and limited nonlinear effects on others. Additionally, metallurgical analysis of fusion zone showed dendritic structures consisted of martensitic with eutectic ferrite along solidification grain and subgrain boundaries.