Title:
STEEL MATERIAL SUITABLE FOR USE IN SOUR ENVIRONMENTS
Document Type and Number:
WIPO Patent Application WO/2023/157897
Kind Code:
A1
Abstract:
Provided is a high-strength steel material that exhibits an excellent SSC resistance in sour environments. The steel material according to the present disclosure comprises, in mass%, C : 0.15% to 0.45%, Si : 0.05% to 1.00%, Mn : 0.05% to 0.30%, P : not more than 0.030%, S : not more than 0.0050%, Al : 0.005% to 0.100%, Cr : 0.30% to 1.10%, Mo : 0.40% to 2.00%, Ti : 0.002% to 0.020%, Nb : 0.002% to 0.100%, B : 0.0005% to 0.0040%, N : not more than 0.0100%, and O : less than 0.0040%, with the balance being Fe and impurities, and has a yield strength of at least 862 MPa. The number density in the steel material of Si oxide having an Si content of at least 20 mass%, an O content of at least 10 mass%, and a long diameter of at least 5.0 µm, is not more than 5/100 mm2; when the yield strength is 931 MPa or more, the Si oxide number density is not more than 5/200 mm2.
Inventors:
KAMITANI HIROKI (JP)
ARAI YUJI (JP)
KAWASAKI JIN (JP)
KONDO KEIICHI (JP)
ARAI YUJI (JP)
KAWASAKI JIN (JP)
KONDO KEIICHI (JP)
Application Number:
PCT/JP2023/005359
Publication Date:
August 24, 2023
Filing Date:
February 16, 2023
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
C21C7/10; C21D9/08; C22C38/00; C22C38/54; C21D8/10
Domestic Patent References:
| WO2021039431A1 | 2021-03-04 | |||
| WO2018074109A1 | 2018-04-26 |
Foreign References:
| JP2008254051A | 2008-10-23 | |||
| CN106399862A | 2017-02-15 |
Attorney, Agent or Firm:
ASCEND IP LAW FIRM (JP)
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