[专利]
Martensite-based chromium-containing steel, and steel pipe for oil well
申请号:
2014EP-0878861
申请日:
2014-12-24
公开号:
EP3095886 A4 2017-09-13 [EP3095886]EP3095886 A1 2016-11-23 [EP3095886]
公开日:
2017-09-132016-11-23
申请人:
NIPPON STEEL & SUMITOMO METAL
专利权人:
NIPPON STEEL & SUMITOMO METAL
发明人:
OMURA TOMOHIKO;TOMIO YUSAKU;TAKABE HIDEKI;MOCHIZUKI TOSHIO
国家:
IPC:
C21D-006/00;C21D-008/02;C21D-008/10;C21D-009/08;C22C-038/00;C22C-038/02;C22C-038/04;C22C-038/06;C22C-038/18;C22C-038/22;C22C-038/24;C22C-038/26;C22C-038/28;C22C-038/32;C22C-038/44;C22C-038/46;C22C-038/48;C22C-038/50;C22C-038/54;E21B-017/00
(EP3095886) A martensitic Cr-containing steel having excellent corrosion resistance, SSC resistance, and IGHIC resistance is provided. A martensitic Cr-containing steel according to the present invention includes: a chemical composition consisting of, by mass%, Si: 0.05 to 1.0%, Mn: 0.1 to 1.0%, Cr: 8 to 12%, V: 0.01 to 1.0%, sol. Al: 0.005 to 0.10%, with the balance being Fe and impurities, wherein an effective Cr amount defined by "Cr - 16.6 x C" is not less than 8%, and an Mo equivalent defined by "Mo + 0.5 x W" is 0.03 to 2%; a micro-structure wherein a grain size number of prior-austenite crystal grain is not less than 8.0, and which consists of, in volume fraction, 0 to 5% of ferrite, 0 to 5% of austenite, with the balance being tempered martensite; and a yield strength of less than 379 to 551 MPa, wherein a grain-boundary segregation ratio of Mo and W is not less than 1.5.