The study is concerned with an analysis of the roll torque using a three-dimensional upper-bound theory for the free ring-rolling process where a spread in the width direction is permitted.
Emphasis is also put on the development of a hydraulic equipment for the horizontal ring-rolling machine.
The theoretical development includes the effect of the difference in the roll diameters of the driven roll and the pressure roll, and the determination of the spread. The ring material is assumed to be rigid-perfectly plastic at the given instant of deformation. Moreover, deformation zone is assumed to be steadystate disregarding the inward movement of the pressure roll and only the rotational velocity is considered.
A kinematically admissible velocity field is derived by finding the equation of a stream line while permitting the difference in roll diameters and the inclusion of the spread. The upperbound method is then applied in order to calculate the theoretical roll torque and also to predict the amount of spread on the free ring surface under constant feed rate.
The experiments are carried out for the annealed aluminum alloy (Al 2014) at room temperature. Comparison of the experimental observation with the theoretical predictions shows that they are in reasonable agreement with each other.
