Hypereutectoid Rail Waist On-Line Heat Treatment Method and Constraint Device

Abstract

The invention discloses an on-line heat treatment method of a rail web for a hypereutectoid steel rail and a restraint device thereof, and belongs to the technical field of metal heat treatment. The on-line heat treatment method comprises the following steps of firstly, controlling the temperature of the steel rail to be at 700 DEG C to 800 DEG C, and detecting the content, in percentage by mass,of carbon in the steel rail; next, sending the steel rail into the restraint device, and applying, by utilizing the restraint device, an accelerative cooling medium to the center of a tread of a railhead of the steel rail, two sides of the railhead and the center of a rail bottom; and finally, when the temperature of the steel rail is decreased to 450 DEG C to 500 DEG C, sending out the steel railfrom the restraint device. The on-line heat treatment method has the beneficial effects that the steel rail is stabilized by utilizing the restraint device; afterwards, the accelerative cooling medium under different pressures is applied to the railhead and the rail bottom of the steel rail according to the content of the carbon in the steel rail; the temperatures of the railhead and the rail bottom are rapidly decreased; the heat at the position of the rail web is caused to rapidly conduct towards two ends; thus, the residual stress of the rail web of the steel rail is decreased; the contentof secondary cementite of a high-carbon steel rail is inhibited; and finally, the overall performance of a weak position of the steel rail is improved.

Description

technical field [0001] The invention relates to the technical field of metal heat treatment, in particular to an on-line heat treatment method for a hypereutectoid rail waist and a constraint device thereof. Background technique [0002] With the gradual development of railways to heavy-haul freight and high-speed passenger transportation, heavy-duty lines have put forward higher requirements for the wear resistance and excellent performance of rails. In order to meet the requirements of heavy-duty lines, hypereutectoid steel rails with a carbon content of ≥0.9% have been developed successively at home and abroad. This steel type has higher strength and toughness, but because it contains secondary cementite, it needs to complete the heating and cooling process. Suppresses the precipitation of reticular secondary cementite content. At present, the cooling of hypereutectoid rails is still in the stage of operation based on the experience of researchers. There is no standardiz...

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Problems solved by technology

At present, the cooling of hypereutectoid rails is still in the stage of operation based on the experience of researchers. There is no standardized operation process and clear control indicators, resulting in a large amount of secondary cementite precipitation and uneven quality of rail waists in hypereutectoid rails. Uneven, poor quality control

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