Development of spatter-suppressed high-power laser beam welding for stainless steel

Laser beam welding is widely used in various industries due to its high degree of automation, remote control capability, and ability to create high-quality welds with a small heat-affected zone. However, high-power laser irradiation often leads to the ejection of a molten metal, known as spatter, which can compromise weld quality by introducing defects such as porosity and underfill. In this study, we propose and investigate the application of multispot laser irradiation as a strategy to mitigate spatter formation. Using a 16 kW disk laser with a wavelength of 1030 nm, bead-on-plate welding experiments were performed on type 304 stainless steel specimens. The number of laser spots was systematically varied from one to three while maintaining a constant total output power of 6 kW. Our findings reveal that multispot laser configurations, particularly the three-spot arrangement, significantly reduced the quantity and velocity of spatter compared to the single-spot case. This reduction is attributed to the stabilization of the molten pool and the fluctuation of recoil pressure dynamics induced by the distributed energy input. High-speed imaging, x-ray observations, and quantitative mass loss measurements substantiate the efficacy of multispot welding in reducing spatter and enhancing process stability.