Title:
油井用高強度ステンレス継目無鋼管およびその製造方法
Document Type and Number:
Japanese Patent JP6766887
Kind Code:
B2
Abstract:
The invention is intended to provide a high-strength stainless steel seamless pipe for oil country tubular goods having high strength with a yield strength of 862 MPa (125 ksi) or more, excellent low-temperature toughness with an absorption energy vE-40of 40 J or more as measured by a Charpy impact test at a test temperature of -40°C, and excellent corrosion resistance. The invention is also intended to provide a method for manufacturing such a high-strength stainless steel seamless pipe. The high-strength stainless steel seamless pipe has a microstructure that is at least 45% tempered martensite phase, 20 to 40% ferrite phase, and more than 10% and 25% or less retained austenite phase by volume. The high-strength stainless steel seamless pipe has a yield strength of 862 MPa or more, and a maximum crystal grain diameter of 500 µm or less for ferrite crystal grains when crystal grains with a crystal orientation difference of within 15° are defined as the same crystal grains.
Inventors:
Yuichi Kamo
Masao Yuzu
Kenichiro Eguchi
Yasuhide Ishiguro
Masao Yuzu
Kenichiro Eguchi
Yasuhide Ishiguro
Application Number:
JP2018557950A
Publication Date:
October 14, 2020
Filing Date:
July 25, 2018
Export Citation:
Assignee:
jfe Steel Corporation
International Classes:
C22C38/00; C21D8/10; C21D9/08; C22C38/54; C22C38/60
Domestic Patent References:
| JP6156609B1 |
Foreign References:
| WO2016132403A1 | ||||
| WO2017010036A1 |
Attorney, Agent or Firm:
Isomura Tetsuro
Akira Kumasaka
Tetsuya Sakai
Kazuhiro Mori
Akira Kumasaka
Tetsuya Sakai
Kazuhiro Mori