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US 10,995,396 B2Granted
Rail
AssigneeNippon Steel Corporation
InventorsMasaharu Ueda, Teruhisa Miyazaki
Life of this patent
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Abstract
A rail according to an aspect of the present invention is manufactured by melting steel using an electric furnace, satisfies a predetermined range as a chemical composition and particularly includes Pb: 0.0003% to 0.0020%, 95 area % or more of a region from an outer surface of a head portion to a depth of 20 mm is a pearlite structure, and a hardness in the region from the outer surface of the head portion to the depth of 20 mm is in a range of Hv 300 to Hv 500.
Claims4
A rail manufactured by melting steel using an electric furnace comprising, as a chemical composition, by unit mass %:
- C:
- 0.75% to 1.20%;
- Si:
- 0.10% to 2.00%;
- Mn:
- 0.10% to 2.00%;
- P≤0.0250%;
- S≤0.0250%;
- Ph:
- 0.0003% to 0.0020%;
- a group a:
- one or two of Cr:
- 0% to 2.00% and Mo:
- 0% to 0.50%;
- a group b:
- Co:
- 0% to 1.00%;
- a group c:
- B:
- 0% to 0.0050%;
- a group d:
- one or two of Cu:
- 0% to 1.00% and Ni:
- 0% to 1.00%;
- a group e:
- one or two or more of \′:
- 0% to 0.50%, Nb:
- 0% to 0.0500%, and Ti:
- 0% to 0.0500%;
- a group f:
- one or two or more of Mg:
- 0% to 0.0200%, Ca:
- 0% to 0.0200%, and REM:
- 0% to 0.0500%;
- a group g:
- Zr:
- 0% to 0.0200%;
- a group h:
- Al:
- 0% to 1.0000%;
- a group i:
- N:
- 0% to 0.0200%;
- and
- a remainder including Fe and impurities,
- wherein 95 area % or more of a region from an outer surface of a head portion to a depth of 20 mm is a pearlite structure,
- a hardness in the region from the outer surface of the head portion to the depth of 20 mm is in a range of dv 300 to 500,
- an impact value is 10.0 J/cm2 or more, and
- the hardness in the region from the outer surface of the head portion to the depth of 20 mm is obtained by measuring the Vickers hardness at 10 or more points under a load of 98 N at each of the measurement position of a depth of 2 ram from the outer surface of the head portion and the measurement position of a depth of 20 mm from the outer surface of the head portion, and calculating the average value thereof.
46 more elements
Dependencies are inferred from the claim text.