Title:
ELECTRIC RESISTANCE-WELDED STEEL PIPE FOR TORSION BEAM
Document Type and Number:
WIPO Patent Application WO/2018/066249
Kind Code:
A1
Abstract:
An electric resistance welded steel pipe for a torsion beam, wherein: a base metal section comprises, in mass%, C: 0.04–0.12%, Si: 0.03–1.20%, Mn: 0.30–2.50%, Ti: 0.08–0.24%, Al: 0.005–0.500%, Nb: 0.01–0.06%, and N: 0.0005–0.0100% and the balance comprises Fe and impurities; Vc90 defined by equation (i) and equation (ii) is at least 200; the content mass ratio of Ti to C is 0.85–5.00; and in the center of the wall thickness of an L cross-section of the base metal section, the ferrite area ratio is at least 80%, the average crystal grain size of the ferrite crystal grains is 10 µm or less, and the average aspect ratio of the ferrite crystal grains is 2.0 or less.
Equation (i): log V c90=2.94−0.75(βa−1)
Equation (ii): βa=2.7C+0.4Si+Mn+0.45Ni+0.8Cr+Mo
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Inventors:
FUKUSHI TAKAAKI (JP)
SHINOHARA YASUHIRO (JP)
HAMATANI HIDEKI (JP)
SHINOHARA YASUHIRO (JP)
HAMATANI HIDEKI (JP)
Application Number:
PCT/JP2017/030205
Publication Date:
April 12, 2018
Filing Date:
August 23, 2017
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C22C38/00; C22C38/58; C21D9/46
Domestic Patent References:
| WO2011145234A1 | 2011-11-24 |
Foreign References:
| JP2003321746A | 2003-11-14 | |||
| JP2003321747A | 2003-11-14 | |||
| JP2003321748A | 2003-11-14 | |||
| JP2009019265A | 2009-01-29 | |||
| JP2011038155A | 2011-02-24 |
Other References:
See also references of EP 3521475A4
Attorney, Agent or Firm:
TAIYO, NAKAJIMA & KATO (JP)
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