A steel rail with excellent contact fatigue performance and its production method

Abstract

The invention relates to a steel rail with excellent contact fatigue performance and a production method thereof. Steel rail with excellent contact fatigue performance, containing 0.68-0.75% C, 0.2-0.8% Si, 0.4%-1% Mn, 0.3%-0.7% Cr, 0.04%-0.12% V, S≤0.01% by weight percentage , P≤0.02%, the balance is Fe and unavoidable impurities. After the billet is rolled to 50-75kg / m section by converter, LF refining, and RH vacuum treatment, the waste heat of the rail is used, and the cooling rate is 5-8 The water mist mixture at ℃ / s accelerates the cooling of the rail head. When the surface temperature of the rail head drops to 500-550°C, it is replaced by compressed air with a cooling rate of 2-4°C / s to continue cooling until the surface temperature of the rail head is low. Stop accelerated cooling at 400°C and air-cool to room temperature. The distance between the rail head tread and the 20mm below the pearlite sheet is 0.07-0.1μm, the tensile strength is ≥1200MPa, the elongation is ≥12%, and it has good 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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