STEEL PIPE FOR FUEL INJECTION PIPE, AND FUEL INJECTION PIPE EMPLOYING SAME

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)

Application Number:

PCT/JP2020/005434

Publication Date:

August 20, 2020

Filing Date:

February 13, 2020

Export Citation:

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Assignee:

NIPPON STEEL CORP (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

Attorney, Agent or Firm:

BRIGHTAS IP ATTORNEYS (JP)

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