The numerical simulation of potential forming problems in a railway wheel and tyre manufacturing process

Railway wheels and tyres are manufactured at ADtranz New Wheel Products Division, Manchester by a multi-stage hot forming process. The process includes forging, piercing and, in many cases, ring-rolling operations. This paper describes the finite element simulation of potential manufacturing problems using the DEFORM(TM) metal forming program. The objective was to compare numerical predictions of surface flaws with experimental observations from case studies in the company. In addition the simulation of internal material flow was evaluated against a physical modelling trial. The automatic multiple operation capability of DEFORM(TM) was used to allow the practical simulation of all the stages, including heat loss between forming operations in the thermo-mechanical simulation. Piercing was modelled by the fracture capability of the software, employing the Cockcroft & Latham damage criteria. Ring rolling was included by developing a generalised plane strain simulation strategy. In general, good correlation was found between the location of forming laps predicted by simulation and that observed in the case studies. High temperature gradients due to die chilling were found by numerical analysis to significantly affect the material flow. The rolling simulations enabled the development of flaws initiated in earlier forming stages to be studied.