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. 03, 2012
Filed:
Oct. 02, 2008
Kikuo Asada, Mishima, JP;
Osamu Endo, Izu, JP;
Katsunori Nagao, Osaka, JP;
Keisuke Hitoshio, Osaka, JP;
Kikuo Asada, Mishima, JP;
Osamu Endo, Izu, JP;
Katsunori Nagao, Osaka, JP;
Keisuke Hitoshio, Osaka, JP;
Sumitomo Metal Industries, Ltd., Osaka-shi, JP;
Abstract
To provide a steel pipe as a fuel injection pipe with high material strength, high internal pressure limit free from fatigue failure, prolonged fatigue life, and high reliability. A steel pipe as a fuel injection pipe of 500 N/mmor higher tensile strength comprising, by mass, C: 0.12 to 0.27%, Si: 0.05 to 0.40%, and Mn: 0.8 to 2.0%, and the balance being Fe and impurities, the contents of Ca, P, and S in the impurities being Ca: 0.001% or less, P: 0.02% or less, and S: 0.01% or less, respectively, characterized in that the maximum diameter of nonmetallic inclusions present in at least in a region extending from the inner surface of the steel pipe to a depth of 20 μm is 20 μm or less. Further, this steel pipe may contain, in place of a portion of Fe, at least one selected from among Cr: 1% or less, Mo: 1% or less, Ti: 0.04% or less, Nb: 0.04% or less, and V: 0.1% or less.