Laser transformation hardening of metal sheets under air and water environment

Laser transformation hardening is a type of surface treatment process for localized hardening of material surface with high control on hardening depth. Further, laser hardening is a self-quenching process with high cooling rate. The current study presents the laser transformation hardening of mild steel under dry and wet environments with single and multi-passes, where the wet environment was created by providing a water-jet parallel to the work-piece surface. The main objective is to study the effect of wet environment on the hardness values and hardening depth in the modified zone due to enhanced cooling. Further, the effect of process parameters, like scan speed, laser power and number of passes on the enhancement of the hardness is also studied. Results indicate significant improvement in the micro-hardness of the treated surface in a water environment under both single and multi-pass conditions.