A Production Method for Improving the Uniformity of Residual Stress in Full Section of F-rail

Abstract

The invention discloses a production method for improving the uniformity of residual stress in the full section of an F-shaped rail, comprising: dividing the F-shaped rail into three cooling areas according to different positions of the section, and adopting Cooling at different cooling rates. Among them, the starting cooling temperature is controlled at 520-600°C, the cooling rate of the first cooling zone is 0.2-0.7°C / s; the cooling rate of the second cooling zone is 0.8-1.3°C / s; the cooling rate of the third cooling zone is 1.4-2.0°C / s, when the surface temperature of the first cooling zone drops to 60-100°C, stop the accelerated cooling, and carry out straightening and finishing. The method provided by the invention reduces the temperature difference across the entire section of the F-rail by reasonably controlling the cooling intensity at each position of the F-shaped rail section after rolling, and the absolute value of the residual stress fluctuation of the entire section is controlled within 100 MPa.

Description

technical field

[0001] The invention relates to a treatment method in the production process of steel rails, in particular to a production method for improving the uniformity of residual stress on the full section of an F-shaped rail, and belongs to the field of metal material production and application. Background technique

[0002] Medium and low-speed maglev trains are an important direction for the development of urban rail transit at present. They have many characteristics such as fast speed, safety, energy saving, and environmental protection. my country has built and operated two medium- and low-speed maglev lines. With the rapid development of urban transportation in my country, the development of maglev railways Showing a momentum of leaps and bounds.

[0003] F-rails are used to manufacture tracks and magnetic poles of maglev railways, to support and guide trains, and their product performance has an important impact on the stability and safety of trains. The shape...

Examples

Embodiment 1

[0039] The chemical composition of F-rail is: C: 0.07%, Si: 0.26%, Mn: 0.90%, Cr: 0.10%, Nb: 0.05%, P: 0.016%, S: 0.008%, and the rest are Fe and impurities element. The production method is as follows: according to the conventional section steel smelting and casting methods, the process includes converter smelting, LF refining, vacuum treatment and continuous casting. Among them, molten iron desulfurization adopts magnesium powder desulfurization process, converter smelting adopts top-bottom combined blowing process, LF refining slag alkalinity is controlled at 1.8-2.3, RH vacuum treatment time is not less than 15 minutes, tundish temperature in continuous casting process It is controlled at 15-20°C above the liquidus line, and the casting speed is 0.6-1.0m / min. The continuous casting process should be carried out under full protection to prevent contact with air. At the same time, the cast billets should be naturally stacked and cooled to room temperature. A walking beam h...

Embodiment 2

[0041] The chemical composition of F-rail is: C: 0.09%, Si: 0.27%, Mn: 1.15%, Cr: 0.13%, Nb: 0.02%, P: 0.011%, S: 0.010%, and the rest are Fe and impurities element. The production method is carried out according to the method of Example 1, the difference is that the rolling process and post-rolling accelerated cooling process parameters are as shown in Table 1.

Embodiment 3

[0043] The chemical composition of F-rail is: C: 0.05%, Si: 0.22%, Mn: 0.85%, Cr: 0.09%, Nb: 0.03%, P: 0.013%, S: 0.009%, and the rest are Fe and impurities element. The production method is carried out according to the method of Example 1, the difference is that the rolling process and post-rolling accelerated cooling process parameters are as shown in Table 1.

technical field

[0001] The invention relates to a treatment method in the production process of steel rails, in particular to a production method for improving the uniformity of residual stress on the full section of an F-shaped rail, and belongs to the field of metal material production and application. Background technique

[0002] Medium and low-speed maglev trains are an important direction for the development of urban rail transit at present. They have many characteristics such as fast speed, safety, energy saving, and environmental protection. my country has built and operated two medium- and low-speed maglev lines. With the rapid development of urban transportation in my country, the development of maglev railways Showing a momentum of leaps and bounds.

[0003] F-rails are used to manufacture tracks and magnetic poles of maglev railways, to support and guide trains, and their product performance has an important impact on the stability and safety of trains. The shape...

Examples

Embodiment 1

[0039] The chemical composition of F-rail is: C: 0.07%, Si: 0.26%, Mn: 0.90%, Cr: 0.10%, Nb: 0.05%, P: 0.016%, S: 0.008%, and the rest are Fe and impurities element. The production method is as follows: according to the conventional section steel smelting and casting methods, the process includes converter smelting, LF refining, vacuum treatment and continuous casting. Among them, molten iron desulfurization adopts magnesium powder desulfurization process, converter smelting adopts top-bottom combined blowing process, LF refining slag alkalinity is controlled at 1.8-2.3, RH vacuum treatment time is not less than 15 minutes, tundish temperature in continuous casting process It is controlled at 15-20°C above the liquidus line, and the casting speed is 0.6-1.0m / min. The continuous casting process should be carried out under full protection to prevent contact with air. At the same time, the cast billets should be naturally stacked and cooled to room temperature. A walking beam h...

Embodiment 2

[0041] The chemical composition of F-rail is: C: 0.09%, Si: 0.27%, Mn: 1.15%, Cr: 0.13%, Nb: 0.02%, P: 0.011%, S: 0.010%, and the rest are Fe and impurities element. The production method is carried out according to the method of Example 1, the difference is that the rolling process and post-rolling accelerated cooling process parameters are as shown in Table 1.

Embodiment 3

[0043] The chemical composition of F-rail is: C: 0.05%, Si: 0.22%, Mn: 0.85%, Cr: 0.09%, Nb: 0.03%, P: 0.013%, S: 0.009%, and the rest are Fe and impurities element. The production method is carried out according to the method of Example 1, the difference is that the rolling process and post-rolling accelerated cooling process parameters are as shown in Table 1.

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