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:
Apr. 22, 2008
Filed:
Apr. 11, 2003
Kunio Kondo, Sanda, JP;
Takahiro Kushida, Amagasaki, JP;
Yuichi Komizo, Nishinomiya, JP;
Masaaki Igarashi, Sanda, JP;
Kunio Kondo, Sanda, JP;
Takahiro Kushida, Amagasaki, JP;
Yuichi Komizo, Nishinomiya, JP;
Masaaki Igarashi, Sanda, JP;
Sumitomo Metal Industries, Ltd., Osaka, JP;
Abstract
A martensitic stainless steel having a C content of 0.01 to 0.1 mass %, a Cr content of 9 to 15 mass % and a N content of not more than 0.1 mass %, wherein the maximum length of the carbides in the steel is 10 to 200 nm in the direction of the minor axis, or wherein the ratio of the average Cr concentration [Cr] to the average Fe concentration [Fe] in carbides in the steel ([Cr]/[Fe]) is not more than 0.4, or wherein the content of MCtype carbides is not more than 1 volume %, the content of MC type carbides is 0.01 to 1.5 volume % and the content of MN type or MN type nitrides is not more than 0.3 volume % is provided. This stainless steel has a high toughness in spite of both a relatively more C content and a high strength, thereby providing a, wide applicability to pipe material for oil wells containing carbon dioxide and a small amount of hydrogen sulfide, in particular for oil wells having a much greater depth.