Novel Cross Wedge Rolling Method for Producing Railcar Axles

Abstract Railcar axles are large-size parts produced in large batches. Nowadays they are manufactured from semi-finished products obtained by press or rotary forging. Studies are conducted on developing more effective methods for producing these parts, with a focus on methods based on rolling processes. A promising line of research in this respect is connected with the use of cross wedge rolling (CWR), a manufacturing method for producing automotive shafts and axles. Nonetheless, there exist no rolling mills that would make it possible to manufacture such large-size parts as railcar axles. A solution to this problem was inspired by the symmetric shape of a railcar axle, which makes it possible to roll this part in two passes using the same tools. The present paper describes this method of manufacturing railcar axles, which was developed at the Lublin University of Technology. Taking advantage of the potential offered by numerical modelling, simulations were made of two rolling processes for producing a railcar axle type BA302, i.e. one process was conducted with the use of two rolls and the other with two flat tools moving in the opposite directions. It was assumed that the rolling processes would be performed on the largest available rolling mills used for CWR. Numerical results demonstrated that railcar axles produced by the proposed rolling process had neither external nor internal (cracks) defects. The effectiveness of the developed CWR method was ultimately confirmed by the high quality of railcar axles that were produced (in a scale of 1:5) under industrial conditions at the Lublin University of Technology.