The effect of laser processing on the structure and wear resistance of wheel steel
Authors:   Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Gubenko S. I. ,   Ukrainian State University of Science and Technologies, ESI "Prydniprovska Academia of Civil Engineering and Architecture", Parusov E. V. ,   Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Chuiko I. M. ,   Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine, Parusov O. V. ,   Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine
Published: January 2025

According to the analysis of literary sources, the expediency of local strengthening of the cove zone of the tread by means of laser treatment has been proven. Based on the study of railway wheels worn during operation, which have a different profile of the tread, it is shown that the flow of intense plastic shear under conditions of sufficiently high contact stresses under operating conditions leads to intensive wear in the zone of the cove, which can lead to undercutting of the crests. It has been established that laser treatment of wheel steel in the pulsed radiation mode creates a laser-strengthened zone with a dispersed martensite structure, which is identical to the "white layer" that forms under operating conditions on the tread. Studies have shown that such a structure is unfavorable from the point of view of exploitation. It is shown that during laser processing in the mode of continuous radiation, it is possible to obtain a microcomposite bainite structure of a laser-strengthened layer, which is favorable for operating conditions. At the same time, the parameters of the strengthened layer, fine steel structure, as well as microhardness and hardness can be varied within certain limits depending on the initial state of the wheel steel, as well as the mode of continuous laser exposure. On the basis of a comparative analysis, it is shown that the modes of laser processing, as well as the degree of dispersion of the initial microstructure, determine the effect of laser strengthening of wheel steel. A promising mode with a laser beam power of 600 W and a speed of its movement of 5–15 mm/s is proposed, which is recommended to be used especially in combination with traditional heat treatment. It is also recommended to carry out local laser strengthening of the cove zone in the conditions of the production of railway wheels after quenching before tempering to reduce thermal stresses. It is shown that the increase in the wear resistance of wheel steel after laser treatment indicates the effectiveness of the application of strengthening laser technology through the purposeful use of internal reserves of the structural adaptability of the surface layers of steel in operational conditions. The prospects of local laser processing of the circle with obtaining a microcomposite bainite structure in the mode of continuous laser radiation are discussed, which will not only increase the wear resistance of the tread of railway wheels, but also reduce the risk of undercutting of the crests during operation. This treatment can be applied both to new railway wheels after traditional heat treatment, and to use it in railway depots during the restoration of worn profiles of the tread by regrinding.