Effect of the Degree of Ovality of the Finishing-Stand Passes in a Reeling Mill on the Accuracy Characteristics and Deformation of the Pipe

Abstract

A study is made of the effect of the degree of ovality of the passes in the finishing stands of an FQM mill on the accuracy and deformation characteristics of the rolled product with the use of a system of 384-mm passes. The transverse distribution of wall-thickness at the outlet of the deformation zone in the fourth and fifth stands is determined for different degrees of ovality of the finishing-stand passes. Relations are obtained to calculate the degree to which the mandrel is enveloped by the metal, the increase in the thickness of the semifinished product, and its spreading for different pass ovalities in the finishing stands of the FQM mill. It is established that it is best to regulate pass ovality in the leader stand in order to significantly improve the accuracy of the rolled pipe’s geometric dimensions.