CAST IRON DIE FOR FORMING LARGE-DIAMETER STEEL PIPE WITH O-PRESS

摘要

PPROBLEM TO BE SOLVED: To extend the service life of a die by reducing the wastage in local parts of the inner peripheral surface which is caused on the die of an O-ing press for forming the large-diameter steel pipe which is used when forming the large-diameter steel pipe by UOE (U-ing, O-ing Press Forming & Expanding) system. PSOLUTION: Spheroidal graphite cast iron is taken as a material for dies of the O-ing press and high hardness is locally given by applying induction hardening to the surface in the vicinity of the local part of the inner peripheral surface of the die where the end part of a steel plate to be formed into the large-diameter steel pipe is brought into contact with the die. The surface hardness of the material of the spheroidal graphite cast iron is 404 (HS) and the depth of the hardened layer which is formed by applying the induction hardening treatment in the vicinity of the local part the of the inner peripheral surface is 3.51.5 mm and the hardened layer is 7510 (HS) in the surface hardness. PCOPYRIGHT: (C)2008,JPO&INPIT