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1. (WO2017154652) STEEL MATERIAL FOR BEARING HAVING EXCELLENT ROLLING FATIGUE CHARACTERISTICS, METHOD FOR MANUFACTURING SAME, AND BEARING COMPONENT

Pub. No.:    WO/2017/154652    International Application No.:    PCT/JP2017/007620
Publication Date: Fri Sep 15 01:59:59 CEST 2017 International Filing Date: Wed Mar 01 00:59:59 CET 2017
IPC: C22C 38/00
C21D 6/00
C21D 8/00
C22C 38/28
F16C 33/62
Applicants: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)
株式会社神戸製鋼所
Inventors: SHIMAMOTO, Masaki
島本 正樹
KIMURA, Sei
木村 世意
OHTA, Hiroki
太田 裕己
IWASAKI, Katsuhiro
岩崎 克浩
OWAKI, Akihiro
大脇 章弘
SUGIMURA, Tomoko
杉村 朋子
Title: STEEL MATERIAL FOR BEARING HAVING EXCELLENT ROLLING FATIGUE CHARACTERISTICS, METHOD FOR MANUFACTURING SAME, AND BEARING COMPONENT
Abstract:
This steel material for a bearing comprises a steel component containing C, Si, Mn, Cr, P, S, Al, Ti, N, and O, the remainder being iron and unavoidable impurities, oxide-based inclusions having a minor axis of 1 µm or greater which are present in the steel material containing Al2O3, SiO2, and TiO2, the remainder comprising unavoidable impurities, the total percentage by mass of Al2O3, SiO2, and TiO2 being 60% or greater, the mass ratio of TiO2 with respect to the total mass of Al2O3 and SiO2 being 0.10 to 1.50, and the percentage of composite inclusions in which TiN is present at the interface with a parent phase of the steel material among the oxide-based inclusions with respect to the total number of oxide-based inclusions being 30% or greater.