The Investigation of lengthwise rolling on a stub mandrel by the use of a computer simulation

Abstract

Lengthwise rolling of pipes on a stub mandrel is one of the most common pipe rolling methods. An urgent problem of the process of lengthwise rolling of pipes on a stub mandrel is the increased wall thickness variation in rough pipes caused by the flow of metal into the groove tapers and the formation of stripes during the rolling process. Therefore, an important direction is the study of the inhomogeneity of the metal flow in the deformation zone during the rolling process. To evaluate the wall thickness variation during the rolling process, a dimensionless parameter was introduced, which is the ratio of the average wall thickness variation in the groove tapers to the average wall thickness at the groove tops. The article presents the results of a study of the influence of mandrel calibration on the wall thickness variation and the tendency to form defects on the inner surface. With the use of computer simulation made for structural alloyed steel AISI-4140, the shape change of the pipe is investigated. Based on the studies, practical recommendations are formulated when choosing the calibration of the mandrel during lengthwise rolling on a stub mandrel, providing increased accuracy of pipes and reducing the level of defects. © 2020 Published under licence by IOP Publishing Ltd.