Improving the Shape of the Two-Roll Round Caliber of Mill for Longitudinal Rolling of Pipes on a Short Mandrel

Abstract

To obtain high-quality pipes, it is necessary to minimize the transverse diversity. To do this, experts create new calibrations of the mill rolls for longitudinal rolling with a short mandrel (automatic, in particular tandem). This work is devoted to improving the shape of the rolls that form the caliber. Another concept of choosing the shape of the fillet successfully has tested in the design of two-roll round calibers with round releases. In this concept it was assumed a smooth connection of the fillet only with the release. The use of the proposed shape in the mill of longitudinal rolling allows to limit the possibility of metal pipe's flow during deformation into the gap between the rolls and, accordingly, to reduce the transverse diversity of the pipe. A method for calculating the geometric parameters of the caliber with a new shape has been developed. New calibration of rolls for longitudinally rolling mills with round caliber and round shape was successfully tested at the rolling mill 140 of OJSC "Interpipe Nico Tube".