Title:
SEAMLESS STEEL PIPE AND METHOD FOR PRODUCING SAME
Document Type and Number:
WIPO Patent Application WO/2018/025778
Kind Code:
A1
Abstract:
A seamless steel pipe which has a chemical composition that contains, in mass%, 0.10-0.20% of C, 0.05-1.0% of Si, 0.05-1.2% of Mn, 0.025% or less of P, 0.005% or less of S, 0.20% or less of Cu, 0.007% or less of N, 0.20-0.50% of Ni, 0.30% or more but less than 0.50% of Cr, 0.30-0.50% of Mo, 0.01-0.05% of Nb, 0.001-0.10% of Al, 0.0005-0.0020% of B, 0.003-0.050% of Ti, 0.01-0.20% of V and 0-0.025% in total of one or more elements selected from among Ca, Mg and REM, with the balance made up of Fe and unavoidable impurities, and wherein: Pcm = (C + (Si/30) + (Mn/20) + (Cu/20) + (Ni/60) + (Cr/20) + (Mo/15) + (V/10) + 5B) ≤ 0.30; the tempered martensite in the metal structure is 90% by area or more; the tensile strength is 980 MPa or more; and the Charpy impact value at -40°C as determined using a 2 mm V-notch test piece is 75 J/cm2 or more.
Inventors:
MIKI TAKESHI (JP)
ARAI YUJI (JP)
MIHARA YUSUKE (JP)
UCHIDA YOHSUKE (JP)
YAMAZAKI MASAHIRO (JP)
YAMAMOTO MASAYUKI (JP)
ARAI YUJI (JP)
MIHARA YUSUKE (JP)
UCHIDA YOHSUKE (JP)
YAMAZAKI MASAHIRO (JP)
YAMAMOTO MASAYUKI (JP)
Application Number:
PCT/JP2017/027529
Publication Date:
February 08, 2018
Filing Date:
July 28, 2017
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; C21D8/10; C21D9/08; C22C38/54
Domestic Patent References:
WO2008050628A1 | 2008-05-02 | |||
WO2010061882A1 | 2010-06-03 |
Foreign References:
JP2016094649A | 2016-05-26 | |||
JP2012193404A | 2012-10-11 | |||
JP2013139610A | 2013-07-18 | |||
JP2006283117A | 2006-10-19 | |||
JP2012107333A | 2012-06-07 |
Attorney, Agent or Firm:
BRIGHTAS IP ATTORNEYS (JP)
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