Steel rail with excellent contact fatigue performance and production method thereof

Abstract

The invention relates to a steel rail with excellent contact fatigue performance and a production method thereof. The steel rail with excellent contact fatigue performance comprises the following elements in percentage by weight: 0.68-0.75% of C, 0.2-0.8% of Si, 0.4%-1% of Mn, 0.3%-0.7 % of Cr, 0.04%-0.12% of V, less than or equal to 0.01% of S, less than or equal to 0.02% of P and the balance of Fe and inevitable impurities. The production method comprises the following steps of carrying out LF refining and RH vacuum treatment in a converter to obtain a square billet, rolling the square billet to form a steel rail of which the cross section is 50-75kg / m, and carrying out accelerated cooling on the rail head part by using the waste heat of the steel rail and adopting a water spray mixed gas with a cooling speed of 5-8 DEG C / s; and when the temperature of the surface of the rail head is cooled to 500-550 DEG C, continuously cooling the rail head by virtue of compressed air with a cooling rate of 2-4 DEG C / s until the temperature of the surface of the rail head is cooled to below 400 DEG C, stopping the accelerated cooling and carrying out air-cooling to room temperature. According to the steel rail disclosed by the invention, the interlamellar spacing in pearlite colonies located at a position from the steel rail head tread to 20mm beneath is 0.07-0.1mu m, the tensile strength of the steel rail is greater than or equal to 1200MPa, the elongation of the steel rail is greater than or equal to 12% and the steel rail has excellent rolling contact fatigue resistance.

Description

technical field [0001] The present invention relates to a steel rail, more specifically, to a steel rail with excellent contact fatigue performance and a production method thereof. Background technique [0002] The rapid development of high-speed and heavy-duty railways has greatly facilitated people's daily travel and efficient transportation of bulk goods. Railway transportation has gradually become the most cost-effective and indispensable transportation mode in the transportation field. The technical problem that has been difficult to solve in the railway industry is wheel-rail rolling contact fatigue. Scientific researchers and technicians have adopted various methods and measures to reduce its hazards, such as developing new materials for wheel-rail and optimizing wheel-rail profile matching to reduce The wheel-rail contact stress and the structural performance of the track and the vehicle are improved to reduce the dynamic effect between the wheel-rail and prolong the...

AI Technical Summary

Problems solved by technology

However, the obvious disadvantage of pearlitic rails is the low ductility and plasticity, which leads to low rolling contact fatigue resistance of the rails. Defects such as injuries and other defects endanger the driving safety of trains. Although the defects can be found in advance and relevant measures can be taken through line inspection or flaw detection, the problem of a sudden fracture of the rails is still a serious problem.

For this reason, the researchers tried another new material --- bainitic steel rail, which has higher fatigue strength but faces a series of problems such as insufficient wear resistance, complicated production process, and high alloying cost. So far, it has not been widely used

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