Title:
SEAMLESS STEEL PIPE FOR LINE PIPE, AND METHOD FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2015/019708
Kind Code:
A1
Abstract:
Provided is a seamless steel pipe for a line pipe, the seamless steel pipe having a chemical composition which contains, in terms of mass %, 0.03-0.10% of C, ≤ 0.50% of Si, 1.0-2.0% of Mn, ≤ 0.050% of P, ≤ 0.005% of S, 0.05-1.0% of Cr, 0.01-0.30% of Mo, 0.001-0.10% of Al, ≤ 0.01% of N, 0.04-2.0% of Ni, 0.0005-0.0050% of Ca, 0-2.0% of Cu, 0-0.05% of Ti, 0-0.05% of Nb and 0-0.10% of V, with the remainder consisting of Fe and impurities, and which satisfies the conditions Cu+Ni: ≥ 0.10% and Mo+V: ≤ 0.30%, wherein metal particles having an average circle-equivalent diameter of 0.1-5 μm and consisting mainly of Ni or Cu are present in scale formed on the surface of the steel pipe, and the distance from the boundary between the base material of the steel pipe and the scale to a region in which the metal particles are not present is 20 μm or higher.
Inventors:
ARAI YUJI (JP)
UEDA YUKIMASA (JP)
MURATA KEI (JP)
HIDAKA YASUYOSHI (JP)
UEDA YUKIMASA (JP)
MURATA KEI (JP)
HIDAKA YASUYOSHI (JP)
Application Number:
PCT/JP2014/065757
Publication Date:
February 12, 2015
Filing Date:
June 13, 2014
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; C21D9/08; C22C38/58; B21B3/00; C21D8/10
Foreign References:
| JP2007031769A | 2007-02-08 | |||
| JP2004176172A | 2004-06-24 | |||
| JP2013139630A | 2013-07-18 | |||
| JP2013082979A | 2013-05-09 | |||
| CN102581553A | 2012-07-18 | |||
| US20070089813A1 | 2007-04-26 | |||
| JP2004143593A | 2004-05-20 | |||
| JPS63143222A | 1988-06-15 | |||
| JPH02282427A | 1990-11-20 | |||
| JPH02243722A | 1990-09-27 |
Other References:
See also references of EP 3031943A4
Attorney, Agent or Firm:
CHIHARA, Kiyosei et al. (JP)
Kiyomasa Chihara (JP)
Kiyomasa Chihara (JP)
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