Manufacturing method for improving low-temperature toughness of hot-rolled U75V steel rail through rare earth elements

Abstract

The invention discloses a manufacturing method for improving the low-temperature toughness of a hot-rolled U75V steel rail by using rare earth elements, which is used for optimizing components and processes of the hot-rolled U75V steel rail and further improving the low-temperature toughness of the steel rail, so that the steel rail has excellent strength, hardness and welding performance at the same time. The rare earth Ce element is added for the hot-rolled U75V steel rail, so that the effects of refining grains, purifying steel and uniformly transforming structures can be achieved, and the low-temperature toughness of the steel rail is further improved while various mechanical properties of the steel rail are ensured. Therefore, low-temperature road steel rail service safety is improved, and line steel rail maintenance cost is reduced.

Description

technical field [0001] The invention relates to the field of metallurgical materials, in particular to a method for manufacturing a rare earth element to improve the low-temperature toughness of a hot-rolled U75V rail. Background technique [0002] At present, domestic freight lines for high-altitude and low-temperature areas mainly use U75V rails with excellent wear resistance, and hot-rolled and quenched rails are used for different sections. The chemical composition of domestic U75V rails is basically the same, and the mechanical properties are basically at the same level, all of which meet the requirements of the "TB / T 2344.1-2020 Rails Part 1 43kgm ~ 75kgm Rails" standard, but the standard does not make specific provisions on the low temperature performance of the rails. [0003] When the rails are used in a low temperature environment for a long time, the problem of brittle fracture may occur, which directly affects the safety of railway transportation. Combined with ...

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Problems solved by technology

[0006] The notification number is CN105238917A. The Chinese patent discloses a method for improving the low-temperature fracture toughness of rails and the obtained rails and their applications. The method for improving the fracture toughness of the rails is that the center of the rail head tread, the two sides of the rail head and the bottom of the rail The central part is subjected to accelerated cooling treatment, the accelerated cooling start temperature is 650-900°C, the cooling rate is 1-5°C / s, the final cooling temperature is 400-550°C, and the fracture toughness at -20°C can be achieved up to 35MPa·m 1 / 2 Above, the above-mentioned invention is through the accelerated cooling treatment of the steel rail, which belongs to the heat-treated steel rail, and the cost of steel per ton of the steel rail increases by 150-200 yuan after the on-line heat treatment

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