Title:
STEEL PIPE FOR FUEL INJECTION PIPE, AND FUEL INJECTION PIPE EMPLOYING SAME
Document Type and Number:
WIPO Patent Application WO/2020/166637
Kind Code:
A1
Abstract:
In this steel pipe for a fuel injection pipe: the chemical composition of the steel pipe is, by mass, C: 0.17 to 0.27%, Si: 0.05 to 0.40%, Mn: 0.30 to 2.00%, P: 0.020% or less, S: 0.0100% or less, O: 0.0040% or less, Ca : 0.0010% or less, Al: 0.005 to 0.060%, N: 0.0020 to 0.0080%, Ti: 0.005 to 0.015%, Nb: 0.015 to 0.045%, Cr: 0 to 1.00%, Mo: 0 to 1.00%, Cu: 0 to 0.50%, Ni: 0 to 0.50%, V: 0 to 0.15%, remainder: Fe and impurities; the metallographic structure substantially comprises tempered martensite, or tempered martensite and tempered bainite; the prior austenite grain size number is at least equal to 9.0; the hardness is 350 to 460 HV1; and if the maximum value of the square root of the surface area of inclusions observed in a cross section perpendicular to the longitudinal direction of the steel pipe is an (n=1 to 20), a maximum value amax of an is at most equal to 30.0 μm, and an average value aav of an is at least equal to 40% of amax.
Inventors:
MAKINO TAIZO (JP)
YAMAZAKI MASAHIRO (JP)
ARAI YUJI (JP)
ENDO OSAMU (JP)
SERIZAWA NAOKI (JP)
MASUDA TATSUYA (JP)
YAMAZAKI MASAHIRO (JP)
ARAI YUJI (JP)
ENDO OSAMU (JP)
SERIZAWA NAOKI (JP)
MASUDA TATSUYA (JP)
Application Number:
PCT/JP2020/005434
Publication Date:
August 20, 2020
Filing Date:
February 13, 2020
Export Citation:
Assignee:
NIPPON STEEL CORP (JP)
USUI CO LTD (JP)
USUI CO LTD (JP)
International Classes:
B21B23/00; C21D9/08; C22C38/00; C22C38/58
Domestic Patent References:
WO2015129617A1 | 2015-09-03 | |||
WO2016038809A1 | 2016-03-17 | |||
WO2016103538A1 | 2016-06-30 | |||
WO2007119734A1 | 2007-10-25 | |||
WO2009008281A1 | 2009-01-15 | |||
WO2015129617A1 | 2015-09-03 |
Foreign References:
JP2010106353A | 2010-05-13 | |||
JP2011084813A | 2011-04-28 | |||
JP2010024503A | 2010-02-04 | |||
JPH0957329A | 1997-03-04 |
Other References:
EISUKE NAKAYAMAMITSUO MIYAHARAKAZUO OKAMURAHIROKI FUJIMOTOKIYOYUKI FUKUI: "Prediction of Fatigue Strength of Spot-Welded Joints Based on Local Material Strength Properties Measured by Small Specimen", J. SOC, MAT. SCI., JAPAN, vol. 53, no. 10, October 2004 (2004-10-01), pages 1136 - 1142
TATSURO KUNITAKE, HEAT TREATMENT, vol. 41, 2001, pages 164
See also references of EP 3925715A4
TATSURO KUNITAKE, HEAT TREATMENT, vol. 41, 2001, pages 164
See also references of EP 3925715A4
Attorney, Agent or Firm:
BRIGHTAS IP ATTORNEYS (JP)
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