Title:
ELECTRIC RESISTANCE WELDED STEEL PIPE FOR LINE PIPES
Document Type and Number:
WIPO Patent Application WO/2020/178943
Kind Code:
A1
Abstract:
An electric resistance welded steel pipe for line pipes, in which a matrix part has a chemical composition comprising, in % by mass, 0.03 to 0.10% of C, 0.03 to 0.60% of Si, 0.30 to 1.60% of Mn, 0.010 to 0.200% of Ti, 0.005 to 0.500% of Al, 0.010 to 0.050% of Nb, 0.0001 to 0.0200% of Ca, and a remainder made up by Fe and impurities, wherein the area ratio of ferrite is 60% or more, the average ferrite grain diameter is 10 μm or less and the ratio of the largest ferrite grain diameter to the average ferrite grain diameter is 3.0 or less in the metal structure of a center part of the matrix part as observed in the thickness direction of the matrix part, the TS is 400 to 700 MPa, the YS is 300 to 650 MPa, the YR is 95% or less, and yield elongation is observed when a tensile test in the tube axis direction is carried out.
Inventors:
FUKUSHI TAKAAKI (JP)
HASEGAWA NOBORU (JP)
OZAKI MASAKAZU (JP)
ICHINOSE YUUSUKE (JP)
NAGAI KENSUKE (JP)
HASEGAWA NOBORU (JP)
OZAKI MASAKAZU (JP)
ICHINOSE YUUSUKE (JP)
NAGAI KENSUKE (JP)
Application Number:
PCT/JP2019/008380
Publication Date:
September 10, 2020
Filing Date:
March 04, 2019
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
International Classes:
C22C38/00; C22C38/58; C21D8/02; C21D9/08; C21D9/50
Domestic Patent References:
| WO2015092916A1 | 2015-06-25 |
Foreign References:
| JP2005290546A | 2005-10-20 | |||
| JP2018127646A | 2018-08-16 | |||
| JP2011017048A | 2011-01-27 |
Attorney, Agent or Firm:
TAIYO, NAKAJIMA & KATO (JP)
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