Studying the Effect of the Mandrel Diameter on the Quality of Pipes Produced by Longitudinal Rolling

摘要

The main trend in the world's pipe rolling production is the use of a continuous longitudinal rolling mill in a pipe-rolling line. In such mills, shells are rolled into pipes using long cylindrical mandrels, which are subject to severe temperature and force conditions. In addition, mandrels are the most expensive tool of continuous mills. The wear of mandrels during rolling, producing different wall thickness with a mandrel of the same diameter, and producing the same wall thickness with mandrels of different diameters necessitate adjusting the position of the rolls in the mill stands. The adjustment of the position of the rolls in the stands of a mill is known to lead to changes in the wall thickness and the formation of defects on the surface of the mother pipe, which affects other parameters of the process. This necessitates experimental study into the process of longitudinal rolling of pipes in order to evaluate the effect of the mandrel diameter on the accuracy of pipes, the angle of contact between the mandrel and the metal, and the overfill of the groove. The defects caused by the irrational choice of the diameter of a cylindrical mandrel are characterized. Lead was used as a model material for making samples during the study.