Development of recommendations on cooling rates of railway wheels with the use of modeling in the software package qform vx 8.2 for the formation of a homogeneous ferritic-perlite structure

Abstract

The tests were performed on ER7 steel according to EN 13262. Based on the hardenability test (GOST 5657) by the method of end hardening (Jomen) the distance from the surface from which unilateral cooling was performed, where the hardness met the requirements of regulatory documentation for wheels of test steel, and the distance where the formation of needle structures, including bainite and otmanshtette, no longer took place. Simulation was applied in the software package QForm VX 8.2, as a result, a model was developed, for the adaptation of which the results of the experiment were used. Confirmed the high convergence of the results of the calculation and the experiment. At the same time, the model allowed to obtain an instantaneous cooling rate in a form that is more in line with the physical meaning of the process and to avoid the scatter of actual values associated with the discreteness of data capture. It is established that the instantaneous cooling rate changes in the process of continuous uniform supply of the cooler. The permissible range of cooling rates of the surface and central sections of the wheel rim during accelerated cooling of ER7 steel is determined. The data can be used to improve the heat treatment modes of railway wheels of current production in order to achieve a high set of mechanical properties both with the existing cooling technology and with differentiated cooling on the modernized equipment of the thermal section of the wheel shop. The developed model can be used to build thermokinetic diagrams under continuous cooling and to develop recommendations for heat treatment modes to achieve the specified mechanical properties under a certain structural state.