Effect of assist gas pressure on cutting quality in underwater cutting of stainless steel using high-power fiber laser

A basic study was conducted to investigate the correlation between assist gas pressure and the amount of secondary waste generated during underwater laser cutting for nuclear decommissioning. The assist gas pressure, i.e. the main parameter, was changed from 2 to 15 bar. Cutting quality was evaluated based on the shape of the cutting cross-section and the roughness of the cutting surface. In addition, the weight loss closely related to the generated secondary waste was calculated, and the schlieren method was used to check the gas flow according to the assist gas pressure. Satisfactory cutting quality could be obtained at a minimum assist gas pressure of 10 bar, and the weight loss related to secondary waste was less. When the cutting quality was good, the weight loss was less, and secondary waste generated was minimum.