Calculation of heat transfer during the manufacture of railway wheels of increased hardness

Abstract

The article is devoted to the study of temperature conditions in the tread of a railway wheel during the production of wheels with increased hardness of the rolling surface. It is shown that obtaining a metal structure on the wheel surface without martensite and with hardness of 360-390 HB required by technical conditions at a depth of 30 mm from the rolling surface is difficult to realize by varying technological parameters: the number of sprayers, changing the water supply to the rolling surface due to the switch on/off the sprayers. To achieve the highest cooling speeds in the mass of the wheel tread, including at a depth of 30 mm, it is necessary to use the largest possible rolling surface in the heat removal process. It is advisable to remove heat from the rolling surface according to a predetermined dependence of the specific heat flux on time.

It was established by experimental studies that the required hardness at a depth of 30 mm was achieved with an increased carbon content in steel and with an increase in the temperature of heating of the wheel before cooling with water spayers of more than 900 °C.

To optimize the cooling process, it is advisable to carry out additional theoretical studies with more correctly specified boundary conditions of heat transfer on the tread surface and with refinement of the boundaries of phase transformations. It is advisable to carry out experimental studies on cooling the wheel surface with the possibility of varying the heat removal when using a gas-liquid flow as a cooling agent.