Title:
AS-ROLLED TYPE ELECTRIC-RESISTANCE-WELDED STEEL PIPE FOR LINE PIPES
Document Type and Number:
WIPO Patent Application WO/2018/179169
Kind Code:
A1
Abstract:
An as-rolled type electric-resistance-welded steel pipe for line pipes wherein: the chemical composition of the base metal section comprises, in mass%, C: 0.01-0.10%, Si: 0.01-0.40%, Mn: 0.50-2.00%, P: 0-0.030%, S: 0-0.0015%, Al: 0.010-0.050%, N: 0.0030-0.0080%, Nb: 0.010-0.050%, and Ti: 0.005-0.020%; the balance comprises Fe and impurities; for the metal structure of the base metal section, the area ratio of polygonal ferrite is 80-98% and the balance is bainite and/or pearlite; the yield strength in the axial direction of the pipe is 415-550 MPa; the tensile strength in the axial direction of the pipe is 461-625 MPa; and the maximum Vickers hardness of the inner surface layer of the base metal section is 248 HV or less and is at least 5 HV less than the maximum Vickers hardness of the outer surface layer of the base metal section.
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Inventors:
TASHIMA KENZO (JP)
SAKAMOTO SHINYA (JP)
ISHITSUKA TETSUO (JP)
FUKUSHI TAKAAKI (JP)
ASAHI HITOSHI (JP)
SAKAMOTO SHINYA (JP)
ISHITSUKA TETSUO (JP)
FUKUSHI TAKAAKI (JP)
ASAHI HITOSHI (JP)
Application Number:
PCT/JP2017/013013
Publication Date:
October 04, 2018
Filing Date:
March 29, 2017
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; C21D8/10; C21D9/08; C22C38/58
Domestic Patent References:
| WO2013027779A1 | 2013-02-28 | |||
| WO2013153819A1 | 2013-10-17 | |||
| WO2016143270A1 | 2016-09-15 |
Foreign References:
| JP2012241273A | 2012-12-10 | |||
| JP2013011005A | 2013-01-17 | |||
| JP2016068749A | 2016-05-09 |
Other References:
See also references of EP 3546610A4
Attorney, Agent or Firm:
TAIYO, NAKAJIMA & KATO (JP)
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