Bainite steel and bainite steel rail used for curve and heavy load steel rail, and production method thereof

A technology of bainitic steel and production method, applied in the fields of machinery manufacturing and metallurgy, can solve the problems of rail failure, short life of curved rails and heavy-duty rails, etc., and achieves lower production costs, high strength and hardness, and reduced Ni content Effect

Active Publication Date: 2010-12-22
BEIJING TEYE IND & TRADE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Similarly, the influence of superelevation of the curve and the influence of heavy load during heavy-duty transportation will also cause local damage to the rail, resulting in a shorter service life of the curved rail and the heavy-duty rail

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] Example 1 Bainite Steel 1

[0025] The raw materials go through converter smelting-ladle refining-vacuum treatment-continuous casting to obtain steel billets,

[0026] The chemical composition and weight percentage of the billet are: C 0.18-0.25, Si0.80-1.20, Mn 2.20-2.40, P≤0.025, S≤0.015, Cr 0.8-1.2, Ni 0.3-0.5, Mo 0.15- 0.25, and the rest are Fe and impurities.

[0027] Control objectives of process parameters in converter smelting process: C<0.08%; P<0.010%; S<0.030%; T≥1640°C.

[0028] The requirements for molten iron, the molten iron for smelting bainitic steel should reach: P<0.15%; S<0.025%; T≥1250℃.

[0029] Vacuum treatment process Vacuum treatment process parameters control objectives: vacuum degree <0.08KPa; deep vacuum time ≥ 15 minutes; soft blowing time ≥ 8 minutes.

[0030] Gas control: H<2.5p.p.m; 0<25p.p.m.

[0031] Continuous casting process: the blank shape is 280mm×380mm, the casting speed is 0.6-0.7m / min during continuous casting, and the elect...

Embodiment 2

[0032] Embodiment 2 Bainitic steel rail 1

[0033] The steel slab obtained in Example 1 is hot-rolled into a steel rail. The heating temperature of the steel slab is 1200-1250°C; the starting rolling temperature is 1180-1200°C; and the final rolling temperature is 880-920°C.

[0034] Rail type: 50kg / m, 60kg / m, 68kg / m, 75kg / m. Dimensional tolerance and straightness are in accordance with TB / T2344-2003 standard.

[0035]Properties of bainite rail after hot rolling: tensile strength 1200-1300MPa; elongation ≥ 10%; room temperature impact toughness ≥ 30J / cm 2 ;Low temperature impact toughness (-20℃)≥20J / cm 2 ; Brinell hardness ≥ 350HB.

[0036] The hot-rolled rails are then heat-treated. The process is: use a horizontal intermediate frequency heating furnace, heating temperature: 880-920°C; holding time: 1-3 hours; cooling process: use air cooling from 920-400°C, cooling speed; 13- 16°C / min, from 350°C to room temperature with air-cooling and natural cooling, and finally heat ...

Embodiment 3

[0038] Example 3 Bainite Steel 2

[0039] The difference from Example 1 is that the chemical elements contained in the bainite steel and their weight percentages are: C 0.18-0.25, Si 0.80-1.20, Mn 2.20-2.40, P≤0.025, S≤0.015, Cr 0.6- 1.0, Mo 0.15-0.25, the rest are Fe and impurities.

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Abstract

The invention discloses a bainite steel and a bainite steel rail used for a curve and a heavy load steel rail, and a heat treatment method thereof. The bainite steel contains the chemical elements by weight percent: 0.16-0.25% of C, 0.70-1.20% of Si, 2.10-2.40% of Mn, less than or equal to 0.025% of P, less than or equal to 0.015% of S, 0.6-1.2% of Cr, 0.15-0.40% of Mo, 0-0.7% of Ni and balance Fe and impurities which are treated by continuous casting, hot rolling and whole heat treatment. The invention can be used for the curve and the heavy load line steel rail, and prolongs the service life of the steel rail.

Description

technical field [0001] The invention belongs to the fields of metallurgy and machinery manufacturing, and in particular relates to a bainitic steel rail for curves and heavy-duty lines. Background technique [0002] With the continuous development of railway transportation in the direction of high speed and heavy load, higher and higher requirements are put forward for the performance of steel rails and turnouts. Railway is the main artery of transportation. In my country, the growth of railway mileage cannot meet the needs of rapid economic growth. Therefore, it is necessary to increase the speed of trains and increase the load to increase transportation capacity. As a result, the existing rails are frequently changed due to overloaded transportation capacity, and the burden of line inspection Intensified, especially in curved and heavy-duty lines, some rails were replaced due to increased wear after only half a year of use, which not only caused a huge waste of resources, b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/58C21D9/04
Inventor 张绵胜张志强张志勇张红娟
Owner BEIJING TEYE IND & TRADE
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