Laser Remelting Power Effect on Microstructure, Hardness and Wear Behavior of AISI 1020

Abstract

In this study, the effect of laser remelting on the microstructure, hardness, and wear properties of AISI 1020 steel was investigated. In this context, laser remelting process was carried out at different laser powers. The surface of steel was subjected to laser remelting process at 1, 1.3, and 1.8 kW powers. Thanks to the applied laser remelting surface modification, martensitic transformation was obtained in the pearlite+ferrite structure. Depending on the applied laser power, the transformation depth increased. The martensitic transformation was determined at a depth of 70 µm at the lowest laser power and 250 µm at the highest laser power. An increase up to 552 HV was achieved after the remelting process on the surface of AISI 1020 steel. Depending on the increasing laser power, the highest surface hardness values decreased. However, the hardness values obtained with increasing laser power were preserved at longer distances towards the center. In ball-on-disc tribology tests, laser remelting has been shown to reduce wear losses by up to 52%. The highest wear resistance was determined in the sample whose surface was modified with the lowest laser power. Laser remelted samples showed lower friction coefficient due to hardness and oxidation on their surfaces.