An Investigation into the Relationship between Torque and Load in Ring Rolling

In the ring-rolling process most of the required forming energy is transferred from the roll into the deforming region by the aid of friction between the roll surface and the ring. In this paper a concept of “equivalent” coefficient of friction (μ_eq) is proposed, which is the ratio of frictional force of the driven roll to pressing load of the pressure roll. Considering the ring geometry and the related kinematics, the relationship between equivalent coefficient of friction and process parameters is derived. The upper-bound torque is also found based on the geometrical simplifications, and the roll of μ_eq for the upper-bound solution is investigated. The effects of various process parameters on equivalent coefficient of friction in ring rolling are then discussed.