Influence of pulse duration on the surface morphology of ASSAB DF-2 (AISI-01) cold work steel treated by YAG laser

A YAG pulsed laser with different pulse durations in the millisecond range was used to spot-irradiate ASSAB DF-2 (AISI-01) cold work steel. The influence of the pulse duration on the surface morphologies of the irradiated spots was studied by scanning electron microscopy (SEM), energy dispersion spectrometry (EDX) and three-dimensional surface profilometry. Results showed that the changes of the surface morphology were not uniform, especially for relatively shorter pulse durations. Surface roughness and morphology of the irradiated DF-2 cold work steel varied with the pulse duration depending on whether melting of the surface material occurred. Relevant mechanisms were discussed. Schematic map was also introduced to describe the change of the surface morphology.