The Use of Laser Surface Modification Technologies for Obtaining Parts of Roller-Screw Mechanism

Abstract

A number of parts of roller-screw mechanisms (RSM), which work in aggressive environments, are made of corrosion-resistant stainless steel 40Cr13 (AISI420 analogue). These elements include a screw and rollers. For these parts, it is necessary to have hard surface layers and a soft core. A promising method for obtaining the necessary requirements is surface laser modification. The article investigated the effect of laser surface treatment on the value of the coefficient of elasticity, hardness, coefficient of friction and the amount of wear of products made of stainless alloy steel 40Cr13. For laser processing, the SVAROG-1-5DR laser complex (Russia) was used. Various modes of surface laser modification were set. For this purpose, the power of the laser power, the speed of movement of the laser beam relative to the treated surface, and the focal length were varied. The Vickers hardness and tribological characteristics were measured using a microcombitester and tribometer manufactured by SSM Instruments SA (Switzerland). The Rockwell hardness was measured using a TN 301 hardness tester manufactured by Time Group (China). The structure of the alloy was studied by metallography and X-ray diffractometry. It was found that the indicators of hardness and wear resistance of the surface layers of sctructural 40Cr13 steel strongly depend on the laser treatment modes. These dependencies are extreme, with highs and lows. The paper presents the quantitative values of the hardness and wear resistance indicators before and after laser treatment of the surface of this steel in various modes. The reasons for the change in the hardness and wear of the surface layers of 40Cr13 steel after laser treatment under different modes are established. The results of the work were used to optimize the modes of laser treatment of the surface of 40Cr13 steel in order to obtain the maximum values of hardness and wear resistance.