Structure of the surface layer and the microhardness of high-carbon instrumental steel after laser treatment

Abstract The article presents the results of the study of the effect of laser treatment on the structure and microhardness of the surface of high-carbon steel samples. The treatment is carried out in order to obtain surface layers, parts with high properties for industries of various purposes. The samples from high-carbon steel U10 A after preliminary thermal treatment by modes of 780–800 °C heating for 2 minutes with cooling in 10 percent water solution of sodium chloride with tempering at 270–320 °C and cooled in the air and without the thermal treatment are treated with the Nd:YAG laser with the capacity up to 1 kW. Metallographic studies and microhardness properties illustrate the influence of laser surface processing on the increase in mechanical properties. It is shown that the laser thermal treatment of steel allows obtaining a surface microhardness of about HV 800-1000 MPa and depends on the original state of the metal and the previous thermal treatment.