Sleeve deformation in a three-roller screw-rolling mill

Abstract

The screw rolling of steel pipe in a three-roller mill is considered. Given the differences in the unitforce distribution within the deformation region, a method is developed for calculating the deformation parameters in sleeve rolling on a long mandrel. A method is presented for calculating the reduction and contact surface area of the metal and the roller, in the region where the diameter of the sleeve is reduced and in the region where the wall thickness is reduced. Account is taken of the tangential flow of metal into the gaps between the rollers, which is characteristic of the rolling of thin-walled pipe when the ratio of the diameter and the wall thickness is D_pi/S_pi > 8. The results are intended for industrial use in the production of pipe with D_pi/S_pi = 8–15, when the tolerances are ±6% on the wall thickness and ±0.5% on the diameter. The results provide a better understanding of the production of thin-walled pipe on screw-rolling mills.