Mechanical component and method for manufacturing mechanical component
AssigneeKomatsu Ltd.
InventorDaigo KANAZAWA
Life of this patent
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Abstract
A spur gear as a mechanical component is made of steel containing 0.12 mass % or more and 0.28 mass % or less of carbon, 0.15 mass % or more and 0.70 mass % or less of silicon, 0.20 mass % or more and 0.95 mass % or less of manganese, and 0.85 mass % or more and 1.90 mass % or less of chromium, with the balance being iron and inevitable impurities, and having a martensitic structure, and includes a carburized layer disposed so as to constitute at least a part of a surface and having a higher carbon concentration than the other portion. The carburized layer includes a composite oxide film disposed so as to constitute the surface, having a thickness of 1 μm or more and 25 μm or less, and containing magnetite and hematite.
Claims20
A mechanical component made of steel containing 0.12 mass % or more and 0.28 mass % or less of carbon, 0.15 mass % or more and 0.70 mass % or less of silicon, 0.20 mass % or more and 0.95 mass % or less of manganese, and 0.85 mass % or more and 1.90 mass % or less of chromium, with the balance being iron and inevitable impurities, and having a martensitic structure, the mechanical component including a carburized layer disposed so as to constitute at least a part of a surface and having a higher carbon concentration than the other portion, wherein
- the carburized layer includes a composite oxide film disposed so as to constitute the surface, having a thickness of 1 μm or more and 25 μm or less, and containing magnetite and hematite.
A mechanical component made of steel containing 0.12 mass % or more and 0.28 mass % or less of carbon, 0.15 mass % or more and 0.70 mass % or less of silicon, 0.20 mass % or more and 0.95 mass % or less of manganese, 0.85 mass % or more and 1.90 mass % or less of chromium, and at least one selected from the group consisting of 0.15 mass % or more and 0.45 mass % or less of molybdenum, 0.01 mass % or more and 2.00 mass % or less of nickel, and 0.04 mass % or more and 0.08 mass % or less of niobium, with the balance being iron and inevitable impurities, and having a martensitic structure, the mechanical component including a carburized layer disposed so as to constitute at least a part of a surface and having a higher carbon concentration than the other portion, wherein
- the carburized layer includes a composite oxide film disposed so as to constitute the surface, having a thickness of 1 μm or more and 25 μm or less, and containing magnetite and hematite.
A method for manufacturing a mechanical component comprising:
- preparing a steel material containing 0.12 mass % or more and 0.28 mass % or less of carbon, 0.15 mass % or more and 0.70 mass % or less of silicon, 0.20 mass % or more and 0.95 mass % or less of manganese, and 0.85 mass % or more and 1.90 mass % or less of chromium, with the balance being iron and inevitable impurities;
- forming the steel material, thereby obtaining a compact;
- heating the compact in an oxidizing atmosphere, thereby forming a composite oxide film containing magnetite and hematite on a surface of the compact;
- heating the compact, on which the composite oxide film is formed, in a carburizing atmosphere at a pressure of 1 kPa or less, thereby forming, on the surface of the compact, a carburized layer having a higher carbon concentration than the other portion with a thickness thicker than the composite oxide film;
- and
- quench-hardening the compact having the composite oxide film and the carburized layer formed thereon.
A method for manufacturing a mechanical component comprising:
- preparing a steel material containing 0.12 mass % or more and 0.28 mass % or less of carbon, 0.15 mass % or more and 0.70 mass % or less of silicon, 0.20 mass % or more and 0.95 mass % or less of manganese, and 0.85 mass % or more and 1.90 mass % or less of chromium, and at least one selected from the group consisting of 0.15 mass % or more and 0.45 mass % or less of molybdenum, 0.01 mass % or more and 2.00 mass % or less of nickel, and 0.04 mass % or more and 0.08 mass % or less of niobium, with the balance being iron and inevitable impurities;
- forming the steel material, thereby obtaining a compact;
- heating the compact in an oxidizing atmosphere, thereby forming a composite oxide film containing magnetite and hematite on a surface of the compact;
- heating the compact, on which the composite oxide film is formed, in a carburizing atmosphere at a pressure of 1 kPa or less, thereby forming, on the surface of the compact, a carburized layer having a higher carbon concentration than the other portion with a thickness thicker than the composite oxide film;
- and
- quench-hardening the compact having the composite oxide film and the carburized layer formed thereon.
Dependencies are inferred from the claim text.