Approximate analysis of roll force in a round–oval–round pass rolling sequence

Abstract This paper presents a semi-analytical method for the prediction of roll force in the oval–round (or round–oval) pass rolling sequence most commonly employed in present continuous rod (or bar) mills. Introduced here is the concept of a weak plane-strain deformation taking into account the deformation characteristics of the workpiece (material) in the roll grooves when the equation for the roll force is formulated. The flow stress (deformation resistance) of the workpiece is characterized by Shida’s constitutive equation. Hot rod rolling experiments were conducted to examine the proposed semi-analytical method. The results reveal that using the weak plane-strain deformation condition is appropriate in solving three-dimensional problems, where it is often necessary to reduce the cost of computation by simplification. For low plain-carbon steel, the roll forces predicted are in good agreement with those obtained experimentally with the rolling temperature changed (800–1100°C).