Stainless steel for oil wells and stainless steel pipe for oil wells

US9783876B2 · kind B2 · utility

Assignee

• NIPPON STEEL & SUMITOMO METAL CORPORATION · JP

Inventors

• Shinjiro Nakatsuka · Tokyo, JP
• Taro Ohe · Osaka, JP
• Hisashi Amaya · Tokyo, JP
• Hideki Takabe · Osaka, JP
• Yohei Otome · Amagasaki, JP
• Yusaku Tomio · Tokyo, JP
• Masanao Seo · Tokyo, JP
• Tomohiko Omura · Tokyo, JP
• Kunio Kondo · Sanda, JP

Key dates

• Filing date: Feb 27, 2013
• Grant date: Oct 10, 2017
• Expiry date: Jul 2, 2034

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C38/005
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A stainless steel for oil wells which has excellent high-temperature corrosion resistance and can stably obtain a strength of not less than 758 MPa is provided. The stainless steel for oil wells contains, by masse, C: not more than 0.05%, Si: not more than 1.0%, Mn: 0.01 to 1.0%, P: not more than 0.05%, S: less than 0.002%, Cr: 16 to 18%, Mo: 1.8 to 3%, Cu: 1.0 to 3.5%, Ni: 3.0 to 5.5%, Co: 0.01 to 1.0%, Al: 0.001 to 0.1%, O: not more than 0.05%, and N: not more than 0.05%, the balance being Fe and impurities, and satisfies Formulas (1) and (2):Cr+4Ni+3Mo+2Cu≧44  (1)Cr+3Ni+4Mo+2Cu/3≦46  (2)