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A kind of ultra-low phosphorus bainite steel and its bainite steel rail

A technology of ultra-low phosphorus bainite steel and ultra-low phosphorus bainite, applied in heat treatment equipment, furnaces, heat treatment furnaces, etc., can solve the problem of incomplete matching between alloy composition design and heat treatment process, and accelerate rail microcrack propagation and Surface peeling, insufficient stability of retained austenite, etc., to avoid insufficient stability, improve resistance to contact fatigue damage, and good strength and toughness

Active Publication Date: 2017-06-16
BEIJING JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the service process, the unstable retained austenite will induce transformation into martensite and release hydrogen even under a small strain, which will accelerate the expansion of rail microcracks and surface spalling, so the service life of the rail The performance is extremely unfavorable, so it is of key significance to control the retained austenite in the bainite rail and improve its stability
[0005] The inventor of the present application took the bainitic steel rail used for the Shuohuang Railway as an example to investigate and found that the alloy composition design and heat treatment process of the steel rail could not be completely matched, resulting in problems such as grain boundary weakening and insufficient stability of retained austenite , which in turn induces contact fatigue damage (such as nuclear damage, peeling damage, etc.) of the rail, resulting in unstable performance of the rail

Method used

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  • A kind of ultra-low phosphorus bainite steel and its bainite steel rail
  • A kind of ultra-low phosphorus bainite steel and its bainite steel rail
  • A kind of ultra-low phosphorus bainite steel and its bainite steel rail

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Example 1 Ultra-low phosphorus bainitic steel 1

[0037] An ultra-low phosphorus bainitic steel comprising:

[0038] C: 0.15wt%, Mn: 2.35wt%, Si: 0.6wt%, Cr: 0.6wt%, Ni: 0.6wt%, Mo: 0.48wt%, P: 0.012wt%, S: 0.020wt%, contained The ratio of the mass percent of Mo to P is equal to 40, and the remainder of the composition is Fe and unavoidable impurities.

[0039] After smelting in converter or electric furnace, compound refining by RH+LF, and continuous casting, the billet is obtained.

Embodiment 2

[0040] Example 2 Ultra-low Phosphorus Bainite Rail 1

[0041] The Bs, Bf, Ms, and Mf of the slab produced in Example 1 were measured: the Bs point was 450°C, the Bf point was 380°C, the Ms point was 380°C, and the Mf point was 200°C.

[0042] hot-rolling the above-mentioned steel billets into rails;

[0043] Cool the rail to 480℃ naturally;

[0044] Cool the rail tread to 240°C at 4°C / s; then raise the temperature of the rail tread to 400°C, stay at 400-380°C for 10 minutes, and then naturally cool to room temperature;

[0045] Finally, the integral rail was tempered at 200°C for 10 hours to obtain an ultra-low phosphorus bainite rail.

[0046] The properties of the obtained ultra-low phosphorus bainite rail: tensile strength 1300-1600MPa, elongation 15-18%, impact value at -40℃ low temperature 80-100J / cm 2 , -40℃ low temperature K IC 60-70MPam -1 / 2 .

Embodiment 3

[0047] Example 3 Ultra-low phosphorus bainitic steel 2

[0048] An ultra-low phosphorus bainitic steel comprising:

[0049] C: 0.18wt%, Mn: 2.25wt%, Si: 1.2wt%, Cr: 0.5wt%, Ni: 0.4wt%, Mo: 0.32wt%, P: 0.007wt%, S: 0.011wt%, contained The ratio of Mo to P by mass is equal to 45.7, and the remainder of the composition is Fe and inevitable impurities.

[0050] After smelting in converter or electric furnace, compound refining by RH+LF, and continuous casting, the billet is obtained.

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Abstract

The invention discloses ultra-low-phosphorus bainite steel which includes the following alloy elements, by mass, 0.15-0.22% of C, 2.15-2.35% of Mn, 0.6-1.5% of Si, 0.3-0.6% of Cr, 0-0.6% of Ni, 0.04-0.48% of Mo, 0.001-0.012% of P and 0.001-0.020% of S, and the balanced being Fe and unavoidable impurities. The ratio of Mo to P is not less than 40. When the bainite steel being low in phosphorus content and reasonable in alloy component design is used for producing steel rails, grain boundary weakening is avoided in the steel rail. The invention also discloses ultra-low-phosphorus bainite steel rail produced from the ultra-low-phosphorus bainite steel.

Description

technical field [0001] The invention relates to the technical field of railway steel. More specifically, it relates to an ultra-low phosphorus bainitic steel and its bainitic rail. Background technique [0002] Heavy-duty high-speed railway transportation has been widely valued by railway departments around the world because of its large capacity, high efficiency and low transportation cost. With the rapid development of my country's social economy and the gradual implementation of medium and long-term railway network planning, my country's heavy-duty high-speed The railway has gradually entered a new period of rapid development. In order to further improve the carrying efficiency and reduce the carrying cost, the axle load, running speed and frequency of the heavy-duty train continue to increase. In this case, the wear and contact fatigue between the wheel and the rail will become more serious. The requirements are getting more and more demanding. Due to insufficient stre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/58C21D9/04C21D8/00C21D1/06
Inventor 高古辉桂晓露谭谆礼张永健惠卫军白秉哲翁宇庆
Owner BEIJING JIAOTONG UNIV