Controlled-rolling and controlled-cooling high-strength pearlitic steel rail and production method thereof

A pearlitic rail, controlled rolling and controlled cooling technology, applied in the direction of temperature control, heat treatment process control, furnace type, etc., can solve the problem that the strength and hardness of pearlitic rail are difficult to further improve, and achieve easy popularization and application, good toughness and plasticity, The effect of increasing strength and hardness

Inactive Publication Date: 2021-03-16
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Based on the above prior art in the production of high-strength heat-treated rails, the rolling recrystallization behavior is not fully regulated, resulting in the difficulty of further improving the strength and hardness of pearlitic rails. The present invention provides a controlled-rolling and cooling-controlled high-strength steel rail and its production method. , by rationally setting the chemical composition, rolling process and post-rolling cooling process, the controlled rolling that regulates the recrystallization behavior can be realized, combined with the production method of controlled cooling after rolling, the strength and hardness of the rail can be improved while maintaining good toughness Plasticity

Method used

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  • Controlled-rolling and controlled-cooling high-strength pearlitic steel rail and production method thereof
  • Controlled-rolling and controlled-cooling high-strength pearlitic steel rail and production method thereof
  • Controlled-rolling and controlled-cooling high-strength pearlitic steel rail and production method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] According to conventional rail smelting and casting methods, the process includes converter smelting, LF refining, vacuum treatment, and continuous casting. Among them, the converter slag alkali is controlled at 2.5-3.8; when the steel water is about 1 / 4, the alloy and a carbonaceous agent such as silicon, manganese, vanadium, and steel flow are added to 3 / 4, alloy, and the carbonaceous compound. Add; LF furnace treatment time should be greater than 40 min; RH vacuum ≤90Pa, pure vacuum processing time should not be less than 20 min, the casting process should be carried out under full protection, preventing contact with air, while casting the steel blank should be cooled. The steel blank is sent to the stepped beam heating furnace heating and heats up, the heating temperature is 1170 ° C, the holding time is 160min, the gas is rolled into a rail, the temperature is 1060 ° C, the final rolling temperature is 860 ° C, and the rails after hot rolling And the rail bottom is car...

Embodiment 2-4

[0040] According to the method of Example 1, the difference is that the heating, rolling and heat treatment process parameters are shown in Table 2, respectively.

[0041] Table 2 Embodiments and contrast acceleration cooling process parameters

[0042]

[0043] The comparative example selects the most mature and application range in the current industry, and the tensile strength, stealing hardness, and broken elongation of the steel rails obtained in the comparative example are inspected in the current industry, according to the method specified in TB / T 2344-2012. Performance indicators such as rate, metallic tissue, cross-sectional rock hardness and fracture toughness, and results are shown in Table 3.

[0044] Table 3 Performance of the embodiment and the proportion

[0045]

[0046] It can be seen that the rail strength and hardness obtained by Example 1-4 is better than that of the U75V wire-heat-treated rail, and has better tough plasticity, and the metallographic tiss...

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Abstract

The invention discloses a controlled-rolling and controlled-cooling high-strength pearlitic steel rail and a production method thereof. The controlled-rolling and controlled-cooling high-strength pearlitic steel rail comprises the following chemical components in percentage by mass: 0.71-0.85% of C, 0.45-0.70% of Si, 0.35-0.70% of Mn, 0.2-1.0% of Cr, 0.05-0.1% of V, 0.005-0.08% of Nb, 0-0.025% ofP, 0-0.015% of S and the balance of Fe and inevitable impurities; and the tensile strength of the steel rail is larger than or equal to 1360 MPa, the ductility is larger than or equal to 12%, the railhead tread hardness is larger than or equal to 390 HB, the hardened layer depth is larger than or equal to 30 mm, the structure is thin-sheet pearlite, and the pearlite lamellar spacing away from theposition 30 mm deep away from the surface of the steel rail is smaller than or equal to 90 nm. The strength and hardness of the steel rail are improved, and meanwhile good toughness and plasticity are kept.

Description

Technical field [0001] The present invention relates to a coincidence-controlled cold and high-strength pearlite steel rail and production method thereof, which is well-fat, and its production method thereof. Background technique [0002] With the increase in railway trains, running speeds and riverside through total quality increases, especially in heavy load freight railways, rails are much more than passenger railways, and rails have become more demanding. . Under such service conditions, the problem of wear and fatigue injuries such as rails are more severe, so it is necessary to continuously improve the strength and hardness of the rails to improve its wear resistance and fatigue damage performance. [0003] Domestic androT rail manufacturers generally use the content of C, Si, Mn elements in the rail steel, and add all of the alloy in the steel, and the alloy reinforcing elements such as the steel, which use the steel rolling after rolling, and the gas is accelerated. To en...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/24C22C38/26C22C33/04C21D9/04C21D11/00B21B37/74
CPCC22C38/02C22C38/04C22C38/24C22C38/26C22C33/04C21D9/04C21D11/00B21B37/74
Inventor 周剑华费俊杰董茂松郑建国王瑞敏欧阳珉路
Owner 武汉钢铁有限公司
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