METHOD OF MANUFACTURING SEAMLESS PIPE

摘要

In this method of manufacturing a seamless pipe, a billet is disposed on a pass line between a pusher and a plug and is moved forward until it is caught between skewed rolls. Then, after the caught billet is in contact with the plug until at least piercing and rolling operation comes to a steady state, the billet is moved forward by the pusher so that the advance speed of the billet is higher than or equal to the advance speed in the steady state which speed is obtained when piercing and rolling operation is made without pushing the billet forward by the pusher. By this manufacturing method, the occurrence of defects on an end part inner surface of a hollow shell can be suppressed.