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:
May. 04, 2021
Filed:
May. 19, 2017
Nippon Steel & Sumitomo Metal Corporation, Tokyo, JP;
Daisuke Matsuo, Tokyo, JP;
Takuji Nakahata, Tokyo, JP;
Hisashi Amaya, Tokyo, JP;
Tsutomu Okuyama, Tokyo, JP;
Hideki Takabe, Tokyo, JP;
NIPPON STEEL CORPORATION, Tokyo, JP;
Abstract
A steel bar for a downhole member is provided that is excellent in SCC resistance and SSC resistance. A martensitic stainless steel bar material for a downhole member of the present embodiment has a chemical composition that contains, by mass %, C: 0.020% or less, Si: 1.0% or less, Mn: 1.0% or less, P: 0.03% or less, S: 0.01% or less, Cu: 0.10 to 2.50%, Cr: 10 to 14%, Ni: 1.5 to 7.0%, Mo: 0.2 to 3.0%, Ti: 0.05 to 0.3%, V: 0.01 to 0.10%, Nb: 0.1% or less, Al: 0.001 to 0.1% and N: 0.05% or less, with the balance being Fe and impurities, and satisfies Formula (1) and Formula (2).[Mo]−4×[total Mo amount in precipitate at R/2 position]≥1.30  (1)[Total Mo amount in precipitate at center position]−[total Mo amount in precipitate at R/2 position]≤0.03  (2)