Piercing of Continuous-Cast Billet on Two-Roller Screw Mills with Liners

Abstract

In billet piercing on two-roller screw mills, the influence of the shape and position of the liner (guide piece) on the ratio of the transverse and longitudinal deformation is analyzed. The quality of the sleeve obtained from the continuous-cast billet is ensured by simulating the parameters of the deformation region so as to increase the proportion of transverse deformation. In the piercing mill, the rollers consist of two conical sections, with a gorge between the cones. A piercing mandrel is mounted between the rollers. The tip of the mandrel projects from the gorge toward the input to the deformation region. Liners (guide pieces) limit the transverse motion. The liners consist of a conical input section, an output section, and an intermediate collar. The proportion of transverse deformation is increased by adjusting the distribution of oval distortion of the blank over the length of the deformation region.