Optimization of multi-electrode surfacing technology for freight car axle box body repair

Abstract

The paper studies the influence of temperature fields during single- and multi-electrode welding and surfacing treatment on deformations of the inner cylindrical surface of the body of the roller axle box of a freight car. The surfacing was performed using flux-cored electrodes of 4 mm diameter (type UONI-13/55, GOST 9467) at constant arc voltage of 24 V and welding current of 320 A. Theoretical studies were performed by the finite element method based on a refined model of the axle box body developed in the ANSYS Workbench 2023 environment, with the determination of zones of maximum thermal impact and analysis of temperatures and deformations in characteristic cross-sections. It is established that an increase in the number of electrodes during surfacing restoration reduces the maximum values of heat input and the ovality of the inner surface of the axle box body. The minimum temperatures and deformations were obtained by using a three-electrode surfacing, in which the ovality decreases by 23.9% compared to a single-electrode one and for three-electrode surfacing is lower than the permissible value by 19-20%. Experimental studies conducted under industrial conditions using a thermal measuring station and thermocouple temperature sensors confirmed the results of numerical modeling. A device for restoring the axle boxes of freight cars was developed and tested, which provides an increase in efficiency and reduces the time of restoration work.