Surface hardening of steel with a low-power laser

A locally developed 200 W CO2 laser with multi-mode output was used to study the surface hardening of different steels. Maximum hardness was achieved in the region where the microstructure was transformed to martensite. The microhardness was found to increase with carbon content. In a new experiment, AISI 1045 steel specimen was first annealed and then treated with laser. The microhardness of annealed samples was found to be higher than the untreated samples. Preliminary results are presented.