Effect of Nd-YAG Laser Parameters on the Surface Hardness of AISI D2 Tool Steel at Different degree of Roughness

This research study focuses on the experimental analysis of surface hardening with laser rays for a sample of tool steel 1.2379 at different surface roughness's and laser parameters.The sample was received in an annealed condition with hardness value of 220 HV. The purpose of the experiment was to determine the effect of surface roughness and laser scanning speed on the surface hardness of the sample and the depth of the molten layer. The results showed that the surface roughness and laser scanning speed influenced the depth and hardness of the provided surface. It was observed that at slower scanning speed and a higher surface roughness, a higher hardness and a deeper cured layer thickness were achieved. A maximum surface hardness of 662 HV was achieved using a laser power of 75 W, a laser spot diameter of 0.5 mm, a pulse rate of 80 kHz, a laser processing speed of 1 mm/s, and at the higher surface roughness.