The Influence of Laser Parameters on the Coloring Effect and Microstructure of Stainless Steel Surface

Nanosecond pulsed, green (532 nm) laser was used to irradiate SUS 304 stainless steel. Black, brown, gray, pink and other colors were obtained on the surface of polished stainless steel by adjusting the three process parameters: scanning interval (Ls), scanning speed (v) and defocusing distance (Dd). Scanning electron microscope (SEM) showed that there were three kinds of structures on the surface of stainless steel: columnar protrusions, droplets and cracks. The results indicated that the three process parameters affected the surface coloring effect and the microstructure formation of stainless steel by changing the total accumulated laser fluence in the scanning area.