Title:
STEEL MATERIAL SUITABLE FOR USE IN SOUR ENVIRONMENT
Document Type and Number:
WIPO Patent Application WO/2020/071217
Kind Code:
A1
Abstract:
Provided is a steel material having a yield strength of 655-965 MPa (95-125 ksi grade) and excellent SSC resistance in a low-temperature sour environment. A steel material according to the present disclosure contains, in terms of % by mass, 0.20-0.35% C, 0.05-1.00% Si, 0.01-1.00% Mn, no more than 0.025% P, no more than 0.0100% S, 0.005-0.100% Al, 0.25-0.80% Cr, 0.20-2.00% Mo, 0.002-0.050% Ti, 0.0001-0.0050% B, 0.0020-0.0100% N, and no more than 0.0100% O, the remainder comprising Fe and impurities, and has a chemical composition satisfying formula (1). The number density of precipitates having an equivalent circle diameter of 400 nm or larger is 0.150/µm2 or less in the steel material. The yield strength of the steel material is 655-965 MPa. The dislocation density ρ of the steel material is 7.0×1014m-2 or less. (1): 5 × Cr-Mo-2 × (V + Ti) ≤ 3.00
Inventors:
YOSHIDA SHINJI (JP)
ARAI YUJI (JP)
ARAI YUJI (JP)
Application Number:
PCT/JP2019/037747
Publication Date:
April 09, 2020
Filing Date:
September 26, 2019
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
C22C38/00; C22C38/54; C21D8/00
Domestic Patent References:
| WO2018074109A1 | 2018-04-26 | |||
| WO2016059763A1 | 2016-04-21 | |||
| WO2018066689A1 | 2018-04-12 | |||
| WO2010150915A1 | 2010-12-29 |
Foreign References:
| JP2015038247A | 2015-02-26 | |||
| JP2000256783A | 2000-09-19 | |||
| JP2000297344A | 2000-10-24 | |||
| JP2005350754A | 2005-12-22 | |||
| JP2012026030A | 2012-02-09 |
Other References:
See also references of EP 3862453A4
Attorney, Agent or Firm:
ASCEND IP LAW FIRM (JP)
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