Title:
PRODUCTION OF INTERNALLY FINNED PIPE
Document Type and Number:
Japanese Patent JPH05228529
Kind Code:
A
Abstract:
PURPOSE: To prevent the degradation in the hardenability of the internally finned pipe by scale formation by forming scale on the surface of a mandrel to prevent seizure and easily executing the scale formation in the extrusion forming of this pipe.
CONSTITUTION: The mandrel consisting of a tool steel contg., by weight, 4.5 to 5.5% Cr and 1.0 to 1.5% Mo is hardened at the temp. of the Ac3 point in the atm. The scale of ≥5μm thickness is formed over the entire part of the surface of the mandrel by the hardening. The extrusion is executed by adjusting the thickness of the formed scale to 5 to 25μm.
Inventors:
YAMADERA YOSHIMI
FUJII SATORU
KIYOSUE TSUNEO
FUJII SATORU
KIYOSUE TSUNEO
Application Number:
JP6927292A
Publication Date:
September 07, 1993
Filing Date:
February 17, 1992
Export Citation:
Assignee:
SUMITOMO METAL IND
International Classes:
B21C23/10; B21C25/04; (IPC1-7): B21C23/10; B21C25/04
Attorney, Agent or Firm:
Raw form Motoshige (1 person outside)