INFLUENCE OF LASER TREATMENT ON THE STRUCTURE OF WHEEL STEEL
Formulation of the problem. The problem of rise of reliability and service life of railway wheels connects not only with elaborate of new constructions of wheels and new steels but also with possibility to use the new methods of strengthening of tread. The goal of work was investigation of influence of laser action on the structure of wheel steel for the possible local strengthening of the zone of cove of railway wheels. Methods. Materials for the study was manufactured wheel steel after hot deformation and heat treatment. Laser pulse radiation processing of wheel steel specimens carried out on installations SES-30M, laser continuous radiation processing of wheel steel specimens carried out on installations LG “Kardamon”. We used research methods - optical microscopy, X-ray, measurement of hardness. Results. It was found that under laser action it is possible to form different structures of wheel steel. Under pulse radiation the laser quenched structures with the type of “white layers” are formed which can to be plasticity under loading. Under continuous radiation the structures of upper and lower bainite are formed which allow not only to rise wear resistance of railway wheels tread but also to reduction of risk of undercut of crests in the time of service. The regimes of heat treatment and laser treatment determine effect of laser strengthening of wheel steel. Scientific novelty. The peculiarities of the structure of wheel steel after different types and regimes of laser treatment was founded. The regimes of laser pulse radiation and laser continuous radiation permiting to receive necessary level of laser strengthening were determined. Practical significance. Using the results obtained enable to develop methods and regimes of laser treatment allowing to strength the zone of cove of railway wheels tread and to reduction of risk of undercut of crests in the time of service.