Effect of Applying Nd-YAG Laser on Microstructure and Hardness of AISI 1012 Steel Surface

The unique characteristics of the laser beam such as directionality, monochromaticity, and brightness make it a very important tool in the surface treatment engineering. The concentrated heat in the laser beam can be precisely directed toward the processed region on the surface. The laser beam power, beam size, and scanning velocity are easily controlled during the different processing methods. Laser surface modifications of metallic materials, such as laser surface melting, laser surface alloying, and laser cladding are some of the most important methods to improve the mechanical properties of the processed layer on the surface. A pulsed Nd-YAG laser surface melted specimens of low carbon steel with a maximum power of 90W at different processing parameters. The rapid melt and solidification of the treated layer produced a refinement in the microstructure. The original microstructure of this steel (Ferrite + Pearlite) has been transformed to new phases of martensitic and bainitic structures. The melted layer consists of the melted pool, the heat affected zone, and the substrate. The maximum hardness of the laser melted layer is more than 400 HV. The effect of different lasers such as high power CW CO2 laser on the mechanical properties and corrosion resistance of steel alloys will be carried out in future studies. Keywords: Nd-Yag Laser, Laser surface treatment, Microstructure and hardness of AISI1012 steel