Method for producing rail
AssigneeJfe Steel Corporation
InventorsMinoru Honjo, Mineyasu Takemasa
Life of this patent
Estimating the term…
Abstract
Provided is a method for producing a rail, with which the sweep in the height direction of a rail before straightening can be suppressed when producing standard rails specified in JIS E 1101. The method includes subjecting a bloom having a chemical composition containing, in mass %, C: 0.60% or more and 0.85% or less, Si: 0.10% or more and 1.00% or less, and Mn: 0.10% or more and 1.30% or less, with the balance being Fe and inevitable impurities, to hot rolling to obtain a rail, subjecting the rail to accelerated cooling under conditions where a cooling start temperature T1 of rail head is 750° C. or higher and 850° C. or lower, a cooling stop temperature T2 of rail head is higher than 700° C., and T1−T2 is 20° C. or more, and then allowing the rail to be naturally cooled.
Claims2
A method for producing a rail, the method comprising
- subjecting a bloom to hot rolling to obtain a rail, wherein the bloom comprises a chemical composition containing, in mass %,
- C:
- 0.60% or more and 0.85% or less,
- Si:
- 0.10% or more and 1.00% or less, and
- Mn:
- 0.10% or more and 1.30% or less,
- with the balance being Fe and inevitable impurities,
- subjecting the rail to accelerated cooling under a set of conditions wherein
- a cooling start temperature of rail head, expressed as T1, is 750° C. or higher and 850° C. or lower,
- a cooling stop temperature of rail head, expressed as T2, is higher than 700° C., and
- T1-T2 is 20° C. or more, and
- then allowing the rail to be naturally cooled,
- wherein an average cooling rate of the surface temperature of the rail head during the accelerated cooling is 1.0° C./s or higher and 10° C./s or lower, and
- an average cooling rate of the surface temperature of the rail head during the natural cooling is 0.2° C./s or higher and 0.6° C./s or lower.
Dependencies are inferred from the claim text.