Low thermal expansion cast steel and method for producing same
AssigneeShinhokoku Material Corp.
InventorsNaoki SAKAGUCHI, Kotaro ONA
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Abstract
The present invention relates to a low thermal expansion cast steel having high strength, high rigidity, and low coefficient of thermal expansion. The low thermal expansion cast steel of the present invention comprises is characterized in that, the chemical composition comprises, by mass %, C: 0 to 0.040%, Si: 0.05 to 0.70%, Mn: 0.10 to 0.70%, Ni: 33.0 to 34.5%, Co: 4.40 to 6.20%, Ti: 1.00 to 2.50%, and the balance of Fe and unavoidable impurities, the average grain diameter of the austenitic structure is 200 μm or less, the tensile strength at 23° C. is 700 MPa or more, and the average coefficient of thermal expansion at 18 to 28° C. is 2.0×10−6/° C. or less.
Claims5
A low thermal expansion cast steel,
- the chemical composition of the cast steel, comprising, by mass %,
- C:
- 0 to 0.040%,
- Si:
- 0.05 to 0.70%,
- Mn:
- 0.10 to 0.70%,
- Ni:
- 33.0 to 34.5%,
- Co:
- 4.40 to 6.20%,
- Ti:
- 1.00 to 2.50%, and
- the balance of Fe and unavoidable impurities,
- an average grain size of an austenite structure of the cast steel is 200 μm or less,
- a tensile strength at 23° C. of the cast steel is 700 MPa or more,
- an average coefficient of thermal expansion at 18 to 28° C. is 2.0×10−6/° C. or less.
Dependencies are inferred from the claim text.