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:
Jun. 13, 2017
Filed:
Mar. 03, 2011
Shuji Hashizume, Kawasaki, JP;
Yusuke Minami, Kawasaki, JP;
Tomomi Taniguchi, Kawasaki, JP;
NKK Tubes, Kawasaki-shi, JP;
Abstract
A purpose of the present invention is to provide a martensitic stainless steel tube exhibiting excellent performance even in severe corrosive environments in which a partial pressure of hydrogen sulfide exceeds 0.03 bar. Provided is a low C-high Cr alloy steel tube for OCTG (Oil Country Tubular Goods) having minimum yield strength of 862 MPa and excellent corrosion resistance, wherein the steel tube contains, in percent by mass, 0.005 to 0.05% C, 12 to 16% Cr, 1.0% or less Si, 2.0% or less Mn, 3.5 to 7.5% Ni, 1.5 to 3.5% Mo, 0.01 to 0.05% V, 0.02% or less N, and 0.01 to 0.06% Ta and satisfies the relationship in the following formula (1), and the rest comprises Fe and unavoidable impurities.25-25 (% Ni)+5 (% Cr)+25 (% Mo)≧0  (1).