METHOD OF MANUFACTURING SEAMLESS TUBE

摘要

PROBLEM TO BE SOLVED: To provide a piercing method using inclined rolls by which the generation of the pieces of a broken tube at the bottom tube-end after rolling is perfectly prevented. SOLUTION: Piercing is performed by providing a small hole in the middle part of the rear end-face of a billet and also using a plug whose tip part is formed into a flat face rectangular to the axial-center line.