Effects of two laser cutting processes on the cutting performance of 50 mm-170 mm thick 20CrNiMo under unassisted blowing conditions

Abstract The kerf size is one of the main factors affecting the efficiency of laser cutting of medium-thick steel under unassisted blowing conditions. In this work, the cutting experiments are conducted to investigate the influence of two different kerf width variation patterns with increasing kerf depth (Case 1 and Case 2) on the cutting performance and cutting efficiency of 50 mm, 80 mm and 170 mm thick 20CrNiMo steel under unassisted blowing conditions by using 10-KW power fiber laser. The same cutting movement speed, defocus amount and cutting scan path are used in the cutting experiments for accurate evaluation of the cutting performance. Qualitative and quantitative analyses of the kerf shape and cutting time are performed to discussion the difference between Case 1 and Case 2. The experiment results indicate that the cutting process of Case 2 is superior to Case 1 in terms of cutting time and kerf morphology. The decrease in cutting time for 50 mm, 80 mm and 170 mm thick specimens by 40%, 57.6% and 56%, respectively. The research provides a reference for further improving the laser cutting efficiency of medium-thickness steel under unassisted blowing conditions.