The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 24, 2013
Filed:
Mar. 23, 2007
Naoya Hirase, Osaka, JP;
Tetsuya Nakanishi, Osaka, JP;
Kazuhiro Shimoda, Osaka, JP;
Hirokazu Okada, Osaka, JP;
Tomio Yamakawa, Osaka, JP;
Yasuyoshi Hidaka, Osaka, JP;
Naoya Hirase, Osaka, JP;
Tetsuya Nakanishi, Osaka, JP;
Kazuhiro Shimoda, Osaka, JP;
Hirokazu Okada, Osaka, JP;
Tomio Yamakawa, Osaka, JP;
Yasuyoshi Hidaka, Osaka, JP;
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Abstract
The present invention is to provide a method for producing duplex stainless steel seamless pipe in which a duplex stainless steel billet can be inhibited from generating an oxide scale on the surface thereof during heating and the generation of outer surface flaw can also be prevented. The billet is heated in the a heating furnace for 1.5 hours or more and 4.0 hours or less at a heating temperature of 1250° C. or more and 1320° C. or less while regulating the average concentration of sulfur dioxide (SO) gas in the atmosphere within the furnace to 0.01 volume % or less.