US 2015/0147223 A1Published application

Bearing steel material with excellent rolling fatigue property and bearing part

AssigneeKabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)

InventorsMasaki Shimamoto, Yosuke Shindo, Masaki Kaizuka, Akihiro Owaki, Sei Kimura, Tetsushi Deura, Tomoko Sugimura

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Abstract

A bearing steel material which contains 0.8-1.1 mass % C, 0.15-0.8 mass % Si, 0.1-1.0 mass % Mn, 1.3-1.8 mass % Cr, up to 0.05 mass % P (0 mass % is excluded), up to 0.015 mass % S (0 mass % excluded), 0.0002-0.005 mass % Al, 0.0002-0.0020 mass % Ca, 0.0005-0.010 mass % Ti, up to 0.0080 mass % N (0 mass % is excluded), and up to 0.0025 mass % O (0 mass % is excluded). The steel material contains oxide inclusions which have an average composition that comprises, in terms of mass %, 20-50% CaO, 20-50% Al2O3, 20-70% SiO2, and 3-10% TiO2.

Claims6

Dependent claims

A bearing steel material, comprising:

iron,
from 0.8 to 1.1 mass % of C,
from 0.15 to 0.8 mass % of Si,
from 0.1 to 1.0 mass % of Mn,
from 1.3 to 1.8 mass % of Cr,
more than 0 mass % and 0.05 mass % or less of P,
more than 0 mass % and 0.015 mass or less of S,
from 0.0002 to 0.005 mass % of Al,
from 0.0002 to 0.0020 mass % of Ca,
from 0.0005 to 0.010 mass % of Ti,
more than 0 mass % and 0.0080 mass % or less of N, and
more than 0 mass % and 0.0025 mass % or less of O,
wherein the steel material comprises oxide inclusions, and the oxide inclusions comprise, on the mass % basis,
from 20 to 50% of CaO,
from 20 to 50% of Al2O3,
from 20 to 70% of SiO2, and
from 3 to 10% of TiO2.

14 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/406,347Filed 17 Jul 2013
Priority: JP 2012-16362324 Jul 2012
Published: 28 May 2015
Term ends: Not estimatedThe source records don’t support an estimate.

Classification20 codes

C22C 38/002
Ferrous alloys, e.g. steel alloys: containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
C21D 9/36
Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor: for balls; for rollers
C21D 9/38
Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor: for roll bodies
C21D 9/40
Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor: for rings; for bearing races

Family

US 9,359,661 B2Related patent
US 2015/0147223 A1This patent

From the US filing history. Foreign family members aren’t listed.

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