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:
Aug. 11, 2020
Filed:
Oct. 31, 2016
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Tetsuo Ishitsuka, Tokyo, JP;
Takashi Tsusue, Tokyo, JP;
Shuji Iwamoto, Tokyo, JP;
Shunichi Kobayashi, Tokyo, JP;
Toshiyuki Ogata, Tokyo, JP;
Osamu Yoshida, Tokyo, JP;
Hideto Kawano, Tokyo, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
Abstract
An as-rolled type K55 electric resistance welded oil well pipe includes, in terms of % by mass, 0.30 to 0.50% of C, 0.05 to 0.40% of Si, 0.50 to 1.20% of Mn, 0 to 0.030% of P, 0 to 0.020% of S, 0.002 to 0.080% of Al, 0 to 0.0080% of N, 0 to 0.30% of Cu, 0 to 0.30% of Ni, 0 to 0.30% of Cr, 0 to 0.10% of Mo, 0 to 0.10% of V, 0 to 0.050% of Nb, 0 to 0.030% of Ti, 0 to 0.0100% of Ca, and the balance being Fe and impurities. In the pipe, a metallographic structure at a position of ¼ of a pipe thickness in an L cross-section at a base metal 90° position is a ferrite-pearlite structure in which prior γ-grains are flattened, includes grain boundary ferrite and intragranular ferrite, and has a rate of a total area of the grain boundary ferrite and the intragranular ferrite, of 10 to 30%.