Method for manufacturing rail, and rail
AssigneeJfe Steel Corporation
InventorsNaoki Iizuka, Ryo Matsuoka, Minoru Honjo, Shigeo Okamoto
Life of this patent
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Abstract
Proposed are the welding conditions under which welds are always stably formed such that the difference in hardness between flash-butt welds and rail base metal and the deflection in a bending test are in better ranges. A plurality of pieces of rail base metal are joined via welds formed by flash-butt welding, where the rail base metal has a chemical composition containing C: 0.60 to 1.20 mass %, Si: 0.10 to 1.50 mass %, Mn: 0.10 to 1.50 mass %, and Cr: 0.10 to 1.50 mass %, with the balance being Fe and inevitable impurities, and the flash-butt welding is performed with an amount of welding heat input of 1.50×105 kA2×sec or more and 4.50×105 kA2×sec or less.
Claims4
A method of manufacturing a rail, comprising joining a plurality of pieces of rail base metal via welds formed by flash-butt welding, wherein
- the rail base metal comprises a chemical composition containing
- C:
- 0.60 mass % to 1.20 mass %,
- Si:
- 0.10 mass % to 1.50 mass %,
- Mn:
- 0.10 mass % to 1.50 mass %, and
- Cr:
- 0.10 mass % to 1.50 mass %,
- with the balance being Fe and inevitable impurities,
- the flash-butt welding is performed with an amount of welding heat input of 1.50×105 kA2×sec or more and 4.50×105 kA2×sec or less,
- an absolute value of difference in hardness between the rail base metal and the welds in a surface layer from a surface of a rail head to a depth of 2.5 mm after the welding is 20 or less in Vickers hardness, and
- deflection of the welds is 20 mm or more.
A rail in which a plurality of pieces of rail base metal are joined via welds, wherein
- the rail base metal comprises a chemical composition containing
- C:
- 0.60 mass % to 1.20 mass %,
- Si:
- 0.10 mass % to 1.50 mass %,
- Mn:
- 0.10 mass % to 1.50 mass %, and
- Cr:
- 0.10 mass % to 1.50 mass %,
- with the balance being Fe and inevitable impurities, and
- an absolute value of difference in hardness between the rail base metal and the welds in a surface layer from a surface of a head of the rail to a depth of 2.5 mm is 20 or less in Vickers hardness, and deflection of the welds is 20 mm or more.
Dependencies are inferred from the claim text.