Title:
HOT EXTRUDING METHOD OF DOUBLE LAYERED TUBE
Document Type and Number:
Japanese Patent JPH08294718
Kind Code:
A
Abstract:
PURPOSE: To finely produce a double layered tube, applicable to severe application environment of boiler, chemical plant, etc., in hot extruding so as not to generate defect of crack and scab, etc., to the outermost layer of difficultly hot workable high alloy, etc.
CONSTITUTION: In the method, in which a billet for double layered tube is hot extruded from a die to produce a double layered tube, a die has an extrusion guiding surface having the angle from the extruding direction in a range of 60-75°. The area ratio of outermost layer of billet for double layered tube is set to ≥22, further, the thickness of outermost layer of double layered tube is set to ≥2.0mm.
Inventors:
ARAKI SATOSHI
NIINUMA SHINJI
ISHIZUKA TETSUO
NIINUMA SHINJI
ISHIZUKA TETSUO
Application Number:
JP12295995A
Publication Date:
November 12, 1996
Filing Date:
April 25, 1995
Export Citation:
Assignee:
NIPPON STEEL CORP
International Classes:
B21C23/00; B21C23/22; B21C25/06; (IPC1-7): B21C23/22; B21C23/00; B21C25/06
Attorney, Agent or Firm:
Yasuhiro Hagiwara (1 outside)