PROCESS FOR PRODUCTION OF COMMON RAILS AND PARTIALLY STRENGTHENED COMMON RAILS

Title:

PROCESS FOR PRODUCTION OF COMMON RAILS AND PARTIALLY STRENGTHENED COMMON RAILS

Document Type and Number:

WIPO Patent Application WO/2009/064013

Kind Code:

A1

Abstract:

The invention provides a common rail which can be produced by using an inexpensive steel product and has excellent fatigue strength and a process for the production of the common rail. The process comprises using as the material a high-strength steel for liquid phase dispersion welding excellent in toughness and fatigue strength which contains by mass C: 0.01 to 0.3%, Si: 0.01 to 0.5%, Mn: 0.01 to 3.0%, Cr: 1.0 to 12.0%, Mo: 0.1 to 2.0%, V: 0.01 to 1.0%, B: 0.0003 to 0.01%, Ti: 0.01 to 0.05%, N: 0.001 to 0.01%, P: 0.03% or below, S: 0.01% or below, O: 0.01% or below, and embrittling elements segregated in grain boundaries, As, Sn, Sb, Pb and Zn: 0.015% or below in total with the balance being unavoidable impurities and Fe and subjecting the steel to liquid phase dispersion welding. The process comprises laser -peening a zone in and around the boundary between an inside face (21) of a branch hole (6) around the opening of the hole (6) and an inside face (22) of a rail hole (5) by irradiation with a pulsed laser beam with a transparent liquid existing in the zone and then removing the surface layer around the opening.

Inventors:

SUGIHASHI ATSUSHI (JP)
HIRANO KOJI (JP)
HASEGAWA YASUSHI (JP)

Application Number:

PCT/JP2008/070971

Publication Date:

May 22, 2009

Filing Date:

November 12, 2008

Export Citation:

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Assignee:

NIPPON STEEL CORP (JP)
SUGIHASHI ATSUSHI (JP)
HIRANO KOJI (JP)
HASEGAWA YASUSHI (JP)

International Classes:

F02M55/02; B23K26/00; C21D1/34; C21D7/06; C22C38/00; C22C38/38; C22C38/58; C25F3/16; B23K20/00; B23K103/04

Foreign References:

JP2007040244A	2007-02-15
JP2006322446A	2006-11-30
JP2003214291A	2003-07-30
JP2007237192A	2007-09-20
JP2006218541A	2006-08-24
JP2004083979A	2004-03-18
JP2007040244A	2007-02-15
JP2004020417A	2004-01-22
JP2004027968A	2004-01-29
JP3373638B2	2003-02-04
JP2006322446A	2006-11-30
JPH02151377A	1990-06-11
JP2008119744A	2008-05-29
JPH07276066A	1995-10-24
JPH09323175A	1997-12-16
JP2004114157A	2004-04-15

Other References: