Characterization of AISI 304 stainless steel based on laser cutting process optimization

Abstract

This study investigates the impact of cutting speed and laser focus position on surface roughness, kerf geometry, and microhardness during fiber laser cutting of 4 mm-thick AISI 304 stainless steel sheet. A series of experimental trials were conducted using fiber laser cutting with cutting speeds ranging from 1.5 to 3.5 m/min and focus settings between 30 and 50%, at fixed power of 2000 W and gas pressure equals 14 bar. Surface roughness (Ra) was found to decrease with increasing cutting speed; the highest Ra value recorded was 5.4 µm at 1.5 m/min and 40% focus, while the lowest value was approximately 4.0 µm at 3.5 m/min and 50% focus. Kerf width similarly decreased with increasing speed and optimal focus, narrowing from 185 µm at 1.5 m/min and 30% focus to as low as 138 µm at 3.5 m/min and 50% focus. Microhardness varied non-linearly, reaching a peak of 270 HV at 2.0 m/min and 30% focus, indicating favorable thermal gradients. SEM, EDS, and XRD analysis validated the outcomes indicative of a balanced performance across all evaluated parameters. These findings guide laser cutting optimization for improved precision and mechanical performance in stainless steel.