Conception of a Three Roll Cross Rolling Process of Hollow Rail Axles

The article presents an innovative method of forming hollow rail axles by cross rolling (CR) in a 3-roll mill. Assessing the correctness of the concept was conducted with numerical simulations in Forge (R) NxT v.3.0. In order to investigate whether the limitation in the form of material cracking would occur in the analysed cross rolling process critical values of the damage function for 42CrMo4 grade steel were determined. A new calibrating test, based on rotary compression of a disc-shaped sample in a channel was developed. Changes to wall thickness, effective strain, temperature and damage function calculated on the basis of the normalised Cockcroft-Latham criterion were determined. Distributions of force parameters were done and power of the rolling mill necessary to produce hollow rail axles were obtained.