Abstract
This paper describes a new method for calculating roll force and torque in Square_??_Oval, Round_??_Oval, Square_??_Diamond, Oval→Oval, and Diamond→Diamond passes. We conducted hot steel bar rolling experiments, and investigated some characteristics related with roll force and torque. The shape of projected contact area can be approximated as follows; in the Square→Oval pass, it is approximated by concave rectangular; in the Round_??_Oval, Oval→Oval and Oval→Square passes, by half ellipse; in the Square_??_Diamond and Diamond→Diamond passes, by cosine curves. The mean deformation resistance can be calculated by an equivalent rectangular transformation method. The non-dimensional roll force and torque arm coefficient are expressed as simple functions of a common roll gap ratio.
