Tribological Properties of Structural Alloy Steels after Laser Surface Modification

The microstructure and tribological properties of the modified surface of 12Kh2N4A (its equivalent is E3310) and 38Kh2MYuA (its equivalent is A290C1M) structural alloy steels after laser treatment (LT) are studied using an ytterbium continuous-wave fiber laser. The laser surface treatment is carried out in air at a laser power of 75 and 100 W and a laser beam scanning velocity varying in the range of 2 to 14 mm/s. The micro- and macrostructures of the steels are examined using metallography and durometry; the structure of the laser-affected areas (LAZ) and steel constituents are determined. The scanning velocity at a laser power of 100 W is shown to have the most significant effect on the LAZ dimensions. The maximum depth of the LAZ during LT without surface melting in the studied modes is 310 μm for 12Kh2N4A steel and 170 μm for 38Kh2MYuA steel. According to the hardening mode, the microhardness in the LAZ increases from 1.36 to 1.97 times for 12Kh2N4A steel and by 2.0–2.6 times for 38Kh2MYuA steel. The tribotests performed using a pin-on-disk configuration show that the reduction of linear wear and wear rate in the 12Kh2N4A and 38Kh2MYuA steels at a hardened layer depth of ~100 μm is 26.6 and 43.9%, respectively.