Abstract: A rail cooling device configured to forcibly cool a rail by jetting a coolant includes a porous plate nozzle including a plurality of nozzle holes configured to jet the coolant to an underside of the base of the rail to cool the underside of the base of the rail. Ends in a width direction of the porous plate nozzle correspond to ends of the underside of the base of the rail. Nozzle holes of the porous plate nozzle at the ends of the width direction are smaller than nozzle holes of the porous plate nozzle at a central part in the width direction, and a maximum value of a distance between centers of the nozzle holes at both ends in the width direction is 30% or more of a width of the underside of the base.

Abstract: A rail cooling device configured to forcibly cool a rail by jetting a coolant includes a porous plate nozzle including a plurality of nozzle holes configured to jet the coolant to an underside of the base of the rail to cool the underside of the base of the rail. Ends in a width direction of the porous plate nozzle correspond to ends of the underside of the base of the rail. Nozzle holes of the porous plate nozzle at the ends of the width direction are smaller than nozzle holes of the porous plate nozzle at a central part in the width direction, and a maximum value of a distance between centers of the nozzle holes at both ends in the width direction is 30% or more of a width of the underside of the base.

Abstract: A rail cooling method for forcibly cooling a rail by jetting a coolant includes jetting the coolant to a foot back part of the rail from a porous plate nozzle in which a nozzle hole at an end in a width direction is smaller than a nozzle hole at a central part in the width direction and causes a cooling capacity for the end in the width direction of the underside of the base of the rail to be lower than a cooling capacity for the central part in the width direction of the underside of the base of the rail.

Abstract: A rail heat treatment device includes a cooling header, an oscillation mechanism, and a control system including: a storage unit that stores therein at least information required for a oscillation control; and a control unit that obtains a permissible range of required cooling time for a rail that satisfies a permissible range of hardness of the rail based on a correlation expression representing a correlation between the cooling time for the rail with the cooling header and the hardness of the rail after cooling, controls a stroke and a speed of relative reciprocation of the rail and the cooling header based on the permissible range of the required cooling time, and causes the oscillation mechanism to perform the relative reciprocation of the rail and the cooling header by the stroke and at the speed.

Abstract: A rail cooling method includes: calculating, based on a relation between temperatures and an amount of warp of the rail cooled to ambient temperature after the forced cooling, the temperatures including a cooling start temperature of the head, a cooling end temperature of the head, a cooling start temperature of the foot and a cooling end temperature of the foot, a target value or a target value range for each of the temperatures so that the amount of warp of the rail at ambient temperature falls within a permissive range; and setting a cooling condition in accordance with the target value or the target value range to perform the forced cooling on the head and the foot.

Abstract: A pearlite rail contains, by % by mass, 0.70 to 1.0% C, 0.1 to 1.5% Si, 0.01 to 1.5% Mn, 0.001 to 0.035% P, 0.0005 to 0.030% S, and 0.1 to 2.0% Cr by mass with the balance being Fe and inevitable impurities, wherein a ?+? temperature range is 100° C. or lower.

Abstract: A rail restraining method for restraining a hot-rolled rail in an upright position at a time of forced cooling of a head portion and a foot portion of the rail includes defining a predetermined position within 2 meters from each of both end faces of the rail along a longitudinal direction of the rail as a first restraining position, defining a predetermined position 3 to 10 meters from the first restraining position in a direction toward center of the rail along the longitudinal direction of the rail as a second restraining position at the time of forced cooling, and restraining displacement of the rail in a vertical direction at the first restraining position and the second restraining position by a restraining force F (kN) that satisfies following Expression (1): F?100/L2??(1) where L2 (m) is a distance between the first restraining position and the second restraining position.

Abstract: A rail cooling method for forcibly cooling a rail by jetting a coolant includes jetting the coolant to a foot back part of the rail from a porous plate nozzle in which a nozzle hole at an end in a width direction is smaller than a nozzle hole at a central part in the width direction and causes a cooling capacity for the end in the width direction of the underside of the base of the rail to be lower than a cooling capacity for the central part in the width direction of the underside of the base of the rail.

Abstract: A rail heat treatment device includes a cooling header, an oscillation mechanism, and a control system including: a storage unit that stores therein at least information required for a oscillation control; and a control unit that obtains a permissible range of required cooling time for a rail that satisfies a permissible range of hardness of the rail based on a correlation expression representing a correlation between the cooling time for the rail with the cooling header and the hardness of the rail after cooling, controls a stroke and a speed of relative reciprocation of the rail and the cooling header based on the permissible range of the required cooling time, and causes the oscillation mechanism to perform the relative reciprocation of the rail and the cooling header by the stroke and at the speed.

Abstract: A rail cooling method includes: calculating, based on a relation between temperatures and an amount of warp of the rail cooled to ambient temperature after the forced cooling, the temperatures including a cooling start temperature of the head, a cooling end temperature of the head, a cooling start temperature of the foot and a cooling end temperature of the foot, a target value or a target value range for each of the temperatures so that the amount of warp of the rail at ambient temperature falls within a permissive range; and setting a cooling condition in accordance with the target value or the target value range to perform the forced cooling on the head and the foot.

Abstract: A high-strength, damage-resistant rail characterized by essentially consists of 0.60 to 0.85 wt. % of C, 0.1 to 1.0 wt. % of Si, 0.5 to 1.5 wt. % of Mn, not more than 0.035 wt. % of P, not more than 0.040 wt. % of S, and not more than 0.05 wt. % of Al, a balance being Fe and indispensable impurity. The rail comprises corner and head side portions having a Brinell hardness H.sub.B of 341 to 405 and a head top portion having a hardness which is not more than 0.9 of the Brinell hardness of the corner and head side portions.

Abstract: A method for manufacturing a high strength rail with good toughness, comprises cooling a rail to Ar.sub.3 transformation point or less after hot rolling; heating said cooled rail at a temperature of an austenite temperature zone ranging from Ac.sub.3 transformation point to 950.degree. C.; and cooling the heated rail. The chemical composition of the rail consists of 0.50 to 0.85 wt. % C, 0.50 to 1.50 wt. % Mn, 0.035 wt. % S or less, 0.10 to 1.00 wt. % Si, 0.035 wt. % P or less, 0.050 wt. % Al or less and the balance of Fe and inevitable impurities.