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:
Oct. 11, 2011
Filed:
Aug. 23, 2006
Yusuke Minami, Kawasaki, JP;
Hitoshi Iijima, Kawasaki, JP;
Motohisa Yoshida, Kawasaki, JP;
Toshihiko Fukui, Kawasaki, JP;
Tatsuo Ono, Kawasaki, JP;
Yusuke Minami, Kawasaki, JP;
Hitoshi Iijima, Kawasaki, JP;
Motohisa Yoshida, Kawasaki, JP;
Toshihiko Fukui, Kawasaki, JP;
Tatsuo Ono, Kawasaki, JP;
NKK Tubes, Kanagawa, JP;
Abstract
The present invention relates to an austenitic stainless steel tube for boiler, used for superheater or reheater in thermal power plant, giving excellent resistance to high temperature steam oxidation, in particular to an austenitic stainless steel tube containing 16 to 20% Cr by weight, and being cold-worked at the inner surface of the tube. The Cr concentration in the vicinity of the inner surface of the steel tube is 14% by weight or larger, and the hardness at 100 μm depth from the inner surface of the steel tube is 1.5 times or larger the average hardness of the mother material or is HV 300 or larger.