Increasing the Service Life of Continuous Rolling Mill Mandrels

A modern pipe-rolling unit intended for the production of seamless pipes includes a continuous rolling mill with a retained mandrel. During operation, the working portion of the mandrel unit of a continuous rolling mill is subject to high temperatures and constant cyclic alternating loads, which results in its wear. The magnitude and nature of the wear of mandrels affect the quality of the inner surface of finished pipes. Also, a significant problem in the production of pipes on a continuous rolling mill is the short service life of mandrels. Moreover, mandrels are mostly imported and very expansive. In normal operating conditions, the amount of wear along the length of the mandrel is not uniform. The wear of mandrels can be made uniform and their service life can be increased by changing the velocity of the mandrel, changing the position of the mandrel at the beginning of the rolling process, or using mandrels of a new design.