Title:
ELECTRIC RESISTANCE WELDED STEEL PIPE, AND METHOD FOR MANUFACTURING SAME
Document Type and Number:
WIPO Patent Application WO/2021/106577
Kind Code:
A1
Abstract:
Provided are an electric resistance welded steel pipe, and a method for manufacturing the same. In this electric resistance welded steel pipe: the steel structure in the heat affected zone of the welded portion mainly consists of the bainitic ferrite phase and/or the bainite phase; the steel structure of a central portion, in the wall thickness, of the heat affected zone of the welded portion is such that the sum of the area ratios of the bainitic ferrite phase and/or the bainite phase is at least 90% of the overall structure of the central portion, in the wall thickness, of the heat affected zone of the welded portion; the steel structure in a position 1 mm, in the wall thickness direction, from the outer surface of the heat affected zone of the welded portion is such that the average crystal grain diameter in the bainitic ferrite phase and/or the bainite phase is at most equal to 20 μm; and the average crystal grain diameter in the bainitic ferrite phase and/or the bainite phase in the position 1 mm, in the wall thickness direction, from the outer surface of the heat affected zone of the welded portion, is at least 0.5 times and at most 2 times the average crystal grain diameter in the bainitic ferrite phase and/or the bainite phase in the central portion, in the wall thickness, of the heat affected zone of the welded portion.
Inventors:
MATSUMOTO ATSUSHI (JP)
NAKAZAWA RYO (JP)
YASUDA JUN (JP)
URAHATA EIICHI (JP)
NAKAZAWA RYO (JP)
YASUDA JUN (JP)
URAHATA EIICHI (JP)
Application Number:
PCT/JP2020/042132
Publication Date:
June 03, 2021
Filing Date:
November 11, 2020
Export Citation:
Assignee:
JFE STEEL CORP (JP)
International Classes:
B21C37/08; B21C37/30; C21D8/02; C21D9/08; C21D9/50; C22C38/00; C22C38/14; C22C38/58
Domestic Patent References:
| WO2016103624A1 | 2016-06-30 | |||
| WO2019131100A1 | 2019-07-04 | |||
| WO2018216638A1 | 2018-11-29 |
Foreign References:
| US6364968B1 | 2002-04-02 | |||
| US20140299236A1 | 2014-10-09 | |||
| JPH0551648A | 1993-03-02 | |||
| JP4105796B2 | 2008-06-25 | |||
| JPS578723B2 | 1982-02-18 |
Other References:
See also references of EP 4043114A4
Attorney, Agent or Firm:
KUMASAKA Akira et al. (JP)
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