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US 2012/0222778 A1Published application
Rolling/sliding part and production method thereof
AssigneeJtekt Corporation
InventorsKatsuhiko KIZAWA, Tsuyoshi Mikami
Life of this patent
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Abstract
A production method of a rolling/sliding part which includes applying a spherodizing annealing treatment to a steel to render an average particle diameter of the carbide of the surface layer portion in a range of 0.3 to 0.6 μm and a maximum particle diameter thereof 4 μm, to render the surface hardness 62 or more by Rockwell C hardness and to render a solid solution carbon amount in a residual austenite of the surface layer portion in a range of 0.95 to 1.15% by weight.
Claims1
A production method of a rolling/sliding part comprising:
- applying a spherodizing annealing treatment to a steel that contains C:
- 0.7 to 0.9% by weight, Si:
- 0.05 to 0.7% by weight, Mn:
- 0.05 to 0.7% by weight, Cr:
- 3.2 to 5.0% by weight, Al:
- 0.04% by weight or less, P:
- 0.03% by weight or less, S:
- 0.03% by weight or less, Ti:
- 0.005% by weight or less, O:
- 0.0015% by weight or less, at least one kind of Mo:
- less than 1.0% by weight and V:
- less than 0.50% by weight and a balance made of Fe and unavoidable impurities to make a lot of carbide precipitate;
- processing into a predetermined shape to produce a processed part raw material;
- heating in a carburizing atmosphere of which carbon potential is in a range of 1.0 to 1.5% at a temperature in a range of 870 to 950° C. to apply a first carburizing treatment followed by quenching;
- subsequently heating in a carburizing atmosphere of which carbon potential is in the range of 1.0 to 1.5% at a temperature in a range of 870 to 910° C. to apply a second carburizing treatment followed by quenching;
- and
- applying a tempering treatment to render an area ratio of a total precipitated carbide of the surface layer portion in a range of 15 to 25%, to render, 50% or more, by the area ratio, of the total precipitated carbide present in a surface layer portion a M7C3 type and/or M23C6 type, to render an average particle diameter of the carbide of the surface layer portion in a range of 0.3 to 0.6 μm and a maximum particle diameter thereof 4 μm, to render the surface hardness 62 or more by Rockwell C hardness and to render a solid solution carbon amount in a residual austenite of the surface layer portion in a range of 0.95 to 1.15% by weight.
14 more elements
Dependencies are inferred from the claim text.