Method for the local hardening of railway wheelsets

Abstract

The object of the invention is increasing the service life or service performance of railway wheelsets. Said technical effect is achieved by the means that, in the method for increasing the service life or service performance of railway wheelsets, in which each wheel is implemented in the form of a cylindrical working part having a running or rolling surface and a rim connected thereto by a radius transition, the metal hardening of the wheelset or of a wheel is carried out by conduction of current through rotating contact rollers, which are pressed under pressure onto the surface to be treated, wherein the heating and hardening of the surface is performed in the form of one or more strips. The invention is characterized in that the heating for the hardening can be carried out in two annular sections, or annular zones, wherein the boundary of the first section begins at the connecting line of the radius transition at the beginning of the rolling surface, and may extend across the entire width of the rolling surface. Preferably, the first annular section extends over a distance of approximately 30 mm across the width of the rolling surface. The boundary of the second section begins at the connecting line of the radius transition at the adjacent rim face and preferably extends up to 35 mm over the width of the rim surface. The local heating in each of the said sections is carried out in the form of one or more annular strips, wherein the heating temperature exceeds the temperature of the phase transition Ac 3 by approximately 60-280° C. If the heating is carried out along multiple strips, the distances between the sections of the heat action of each strip are preferably at least approximately 2-4 mm from each side of the heating zone. The rotational speed of the wheelset during heating is preferably approximately 3.5-15 rotations per hour.

1 . Method for local hardening, in particular of railway wheels, wherein each wheel is implemented in the form of a cylindrical working part having a rolling surface, and a rim connected to the cylindrical working part by a radius transition, comprising the metal hardening of the wheel by conduction of current through rotating contact rollers, which are pressed under pressure onto the surface to be treated, wherein the heating and hardening of the surface is performed in the form of one or more strips, characterized in that the heating for the hardening is carried out in a first and/or a second annular section, wherein the boundary of the first annular section begins at the connecting line of the radius transition at the beginning of the rolling surface and the boundary of the second annular section begins at the connecting line of the radius transition at the adjacent rim face, wherein the local heating in each of the said sections is carried out in the form of one or more annular strips, wherein the heating temperature is approximately 60-280° C. higher than the temperature of the phase transition Ac 3 . 
   
   
       2 . Method according to  claim 1 , wherein the first annular section extends over an area of approximately 30 mm across the width of the rolling surface. 
   
   
       3 . Method according to  claim 1 , wherein the second annular section extends over an area of up to approximately 35 mm across the width of the rim surface. 
   
   
       4 . Method according to  claim 1 , wherein the distances between the zones of the heat action of each annular strip are at least approximately 2-4 mm from each side of the heating zone. 
   
   
       5 . Method according to  claim 1 , wherein the rotational speed of the wheel during heating is approximately 3.5-15 rotations per hour. 
   
   
       6 . Method according to  claim 1 , wherein the strips of heating are continuous or discontinuous annular sections.