A kind of high-strength bainitic steel rail and its production method

Abstract

The invention relates to a rail material, in particular to a high-strength bainite rail and a production method thereof. The technical problem to be solved by the present invention is to provide a high-strength bainitic steel rail and a production method thereof. In the present invention, the steel containing 0.15-0.30% C, 1.00-1.80% Si, 1.50-2.50% Mn, 0.20-0.60% Cr, 0.05-0.10% Mo, and the balance is Fe is heated and rolled into the required section After the rail, using the waste heat of the rail, when the rail head tread is naturally cooled to 450-500°C, adopt a cooling rate of 3.0-6.0°C / s to accelerate the cooling of the rail head of the rail. When the center temperature of the rail head tread drops to 220- Stop accelerated cooling at 300°C and air cool to room temperature to obtain carbide-free bainite + a small amount of martensite + a small amount of retained austenite composite phase steel. This steel has excellent wear resistance and is suitable for heavy-duty railway applications.

Description

technical field [0001] The invention relates to a rail material, in particular to a high-strength bainite rail and a production method thereof. Background technique [0002] The rapid development of railway technology puts forward higher requirements for the service performance of rails. At present, my country's railway rails are mainly pearlite series carbon rails with a carbon content of 0.60% to 0.85%, microalloyed rails and high-strength heat-treated rails, and a small amount of bainite rails are also used. Pearlitic steel rail has the characteristics of simple production process, low production cost, stable structure and performance. However, pearlitic rails also have certain deficiencies, such as low contact fatigue strength at the same strength level, and the rail head is prone to peeling off pieces, cracks, nuclear damage and other damages under the reciprocating stress of the wheels, which is not conducive to the development of railway longevity , especially in re...

AI Technical Summary

Problems solved by technology

However, pearlitic rails also have certain deficiencies, such as low contact fatigue strength at the same strength level, and the rail head is prone to peeling off pieces, cracks, nuclear damage and other damages under the reciprocating stress of the wheels, which is not conducive to the development of railway longevity , especially in recent years, with the continuous increase of railway traffic density and vehicle axle load, the service environment of rails has become more and more harsh, and some road sections, especially curved parts, have been in service for less than a year or even a few months due to serious damage or wear to the limit, etc. The reason is to replace the lower track in advance, which reduces the driving efficiency and brings hidden dangers to the safety of railway transportation

Taking my country as an example, the proportion of 100m long rails has exceeded the previous 25m fixed length. For bainite rails, tempering treatment is required, and the conditions for tempering 100m long rails are not yet available under the current conditions. Limits the large-scale application of bainite rail

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