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Title:
STEEL WITH FINELY DISPERSED INCLUSION SUPERIOR IN FATIGUE LIFE
Document Type and Number:
Japanese Patent JP2004277777
Kind Code:
A
Abstract:

To provide a steel which has the adequate fatigue life and superior sound characteristics, by resolving the adverse effect of oxide-based inclusions.

A steel with finely dispersed inclusions superior in the fatigue life includes, by wt.%, 0.05% or less (including 0%) Al, 0.005% or less T.O, and REM in such an amount as to satisfy expression (1): -30<REM (ppm)-T.O (ppm)×280/48<50; includes REM-containing inclusions (oxides, sulfides, oxysulfides, nitrides and composite inclusions thereof ) by such a number proportion with respect to all inclusions (oxides, sulfides, oxysulfides, nitrides and composite inclusions thereof ) having a grain size of 1 μm or larger by an equivalent circle diameter, as to satisfy expression (2): (REM-containing inclusions number)/(all inclusions number)>0.8; and satisfies a condition that the concentration of Al2O3 contained in the REM-containing inclusions is 30 wt.% or lower (including 0%).


Inventors:
HIRATA HIROSHI
ISOBE KOICHI
Application Number:
JP2003068541A
Publication Date:
October 07, 2004
Filing Date:
March 13, 2003
Export Citation:
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Assignee:
NIPPON STEEL CORP
International Classes:
C21D7/04; C21D7/06; C22C38/00; C22C38/18; F16C33/30; C22C38/28; C23C; (IPC1-7): C22C38/00; C22C38/18; C22C38/28; F16C33/30
Attorney, Agent or Firm:
Takashi Ishida
Jun Tsuruta
Hiroshi Kamematsu
Masaya Nishiyama