Changes in surface characteristics of stainless steel polished by nanosecond laser based on beam coupling

Abstract

The laser polishing process of metal materials has been extensively studied. This paper proposes a new type of beam-coupled laser polishing method to study the surface quality of polished stainless steel when the power and frequency change, and the changes of the surface roughness and topography with the laser power and frequency were analyzed. Under the condition of power 0.5W and frequency 10Khz, as the feed speed changes from 200mm/min to 1200mm/min, the surface roughness first decreases, then slightly increases. The single pulse energy decreases, and the surface roughness first increases and then decreases with increasing of the frequency from 10kHz to 20kHz. With low repetition frequency and single pulse energy, the surface roughness is significantly reduced to 0.19μm at the process parameters of 2.0W, 10Khz, and 600mm/min. Under the specific process parameters, the processed surface has a color change similar to that caused by surface quenching treatment. The surface material absorbs more laser light, and the processed surface microstructure changes. By adjusting the process parameters, the polishing quality can be improved. It is proved that the beam-coupled laser polishing of stainless steel is an effective polishing method.