Correlation between Wear Resistance of High-Speed Steel R6M5 and Deformations Arising during Laser Hardening

Abstract

The research of deformation of samples made from high-speed steel R6M5 and treated by volumetric pulsed laser hardening (VPLH) under various laser exposure modes and measurement topology (laser radiation energy, distance from the irradiation site) were carried out using strain measurement. It was found that after VPLH treatment of the samples there are deformations in the longitudinal and transverse sections. This fact indicates the volumetric nature of the deformation changes in the material, and at the same time, it shows the pronounced extremum of relative deformations, which depends on the previously listed conditions of exposure and measurement. The results of abrasive wear tests showed the greatest effect of VPLH for the laser irradiation energy of 300 J and the distance from the irradiation site of 24 mm, which corresponds to the results obtained by the strain measurement for the determination of the samples’ relative deformations. The received extremum corresponds to the optimal hardening modes when changing the relative deformation by 1.06 times and increasing of the hardened resistance samples by 2.3 times. The possibility of joint use (convergence) of the tests results for abrasive wear was determined using the method of retrospective (a posteriori) randomization. This allows recommending the strain measurement method for the optimal modes of VPLH determination and can help to significantly reduce the cost of material consumption and labor intensity of laboratory tests, especially in the process of determining the modes for the samples with variable inputs (structure and chemical composition of materials, geometric parameters of products, operating modes, etc.).