Influence of high-power diode laser heat treatment on wear resistance of a mold steel

The effect of hardness on wear loss and wear behavior during fretting was studied. A high-power diode laser was used to achieve the surface hardening of a mold steel (AISI P20-improved) at temperatures of 1000 and 1200 °C. A hardness increment was detected in laser heat-treated specimens, which may be attributed to phase transformation from ferrite to martensite, influencing wear loss and fretting wear behavior. In the fretting test results, smaller wear scars and less wear loss were observed for laser heat-treated specimens in comparison to those of base metal. Moreover, relatively more stable friction coefficient profiles were obtained for the laser heat-treated specimens due to uniform contact characteristics at two contacting surfaces. The effectiveness of the proposed technique was verified by the morphology of the wear scars of the treated specimens, which had a smooth appearance and minor abrasion grooves.