Effect of Laser Power Control on Welding Defects in Circumferential Welding of Stainless Steel through Partial Penetration Laser Welding

Laser welding was applied to the pipe-flange joint of the media coupling for supplying fuel to the submarine fuel cell. Welding was performed on a flat plate that simulated circumferential welding, and partial penetration welding was applied. Welding conditions were selected to satisfy the bead width and penetration depth required for the prototype through the bead welding experiment. Subsequently, laser power control was applied to the beginning and ending of welding to suppress welding defects in the overlapping area where the beginning and ending of the weldment that porosities, cracks, and craters mainly occur. The cross-section, microstructure, heat-affected zone, and hardness characteristics of the butt weldment were analyzed, and a sound weldment with suppressed porosities, cracks, and craters was obtained.