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Production method capable of reducing fatigue crack growth rate of bainite steel rail

A technology of fatigue crack growth and production method, which is applied in the production field of reducing the fatigue crack growth rate of bainitic rails, can solve the problems of long production cycle, unsatisfactory production rhythm, high production cost, etc., and achieve high tensile strength and reduce fatigue Crack growth rate, effect of reducing center segregation

Active Publication Date: 2017-10-03
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

The disadvantage of this method is that the production process is too complicated, the actual rolling production cannot meet the production rhythm, the production cycle is long, and the output is low, resulting in high production costs.

Method used

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  • Production method capable of reducing fatigue crack growth rate of bainite steel rail

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0016] A production method for reducing the fatigue crack growth rate of a bainite rail, comprising the following steps:

[0017] 1) When smelting and deoxidizing, the basicity of the slag refined outside the LF furnace is controlled at 1.87, and the slag inclusions are controlled at calcium plagioclase (CaO·Al 2 o 3 2SiO2 2 ) plastic region;

[0018] 2) During continuous casting, the temperature of the tundish is controlled at 12°C above the liquidus line, and the casting speed is controlled at 0.5m / min; the 280*380mm bloom is continuously cast by liquid core pressing and electromagnetic stirring technology, and the current intensity is 750A , frequency 8Hz; the terminal liquid core is lightly pressed down by 10mm, the equiaxed grain rate of the cast slab is 98%, and the cast slab is stacked in the slow cooling pit and the heat preservation cover for 48 hours.

[0019] In the rolling step, the heating process is 1087°C for slab heating zone I, 1242°C for slab heating zone ...

Embodiment 2

[0022] A production method for reducing the fatigue crack growth rate of a bainite rail, comprising the following steps:

[0023] 1) When smelting and deoxidizing, the basicity of the slag refined outside the LF furnace is controlled at 2.2, and the slag inclusions are controlled at calcium plagioclase (CaO·Al 2 o 3 2SiO2 2 ) plastic region;

[0024] 2) During continuous casting, the temperature of the tundish is controlled at 18°C ​​above the liquidus line, and the casting speed is controlled at 0.3m / min; the 280*380mm bloom is continuously cast by liquid core pressing and electromagnetic stirring technology, and the current intensity is 600A , frequency 8Hz; the terminal liquid core is lightly pressed down by 10mm, the equiaxed grain rate of the slab is 96%, and the slab is stacked in the slow cooling pit and the heat preservation cover for 48 hours.

[0025] In the rolling step, the heating process is 1052°C for slab heating zone I, 1211°C for slab heating zone II, 1229°...

Embodiment 3

[0028] A production method for reducing the fatigue crack growth rate of a bainite rail, comprising the following steps:

[0029] 1) When smelting and deoxidizing, the basicity of the slag refined outside the LF furnace is controlled within the range of 2.0, and the slag inclusions are controlled within the calcium plagioclase (CaO·Al 2 o 3 2SiO2 2 ) plastic region;

[0030] 2) During continuous casting, the temperature of the tundish is controlled at 15°C above the liquidus line, and the casting speed is controlled at 0.3m / min; the 280*380mm bloom is continuously cast by liquid core pressing and electromagnetic stirring technology, and the current intensity is 600A , frequency 8Hz; the terminal liquid core is lightly pressed down by 10mm, the equiaxed grain rate of the cast slab is 98%, and the cast slab is stacked in the slow cooling pit and the heat preservation cover for 48 hours.

[0031] In the rolling step, the heating process is 1132°C for slab heating zone I, 1243°...

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Abstract

The invention discloses a production method capable of reducing the fatigue crack growth rate of a bainite steel rail. The production method specifically comprises the steps as follows: during smelting and deoxidation, the slag basicity of refining slag is controlled in the range of 1.8-2.3, and slag inclusions are controlled in the plastic range of anorthite; the temperature of a continuous casting tundish is 10-20 DEG C higher than the liquidus, and the pulling rate is controlled to range from 0.3 m / min to 0.5 m / min; a casting blank is obtained with a liquid core reduction technology, and the equiaxial crystal ratio of the casting blank is controlled to be higher than 95%. The composition and the size of the inclusions are controlled with the technology, tiny total-equiaxial crystal continuous casting is formed, the center segregation is reduced, in the later period, the bainite steel rail produced finally with the heating technology, the proper cooling technology and the heat treatment technology is higher in strength than a bainite steel rail prepared with a conventional smelting method, the fracture toughness KIC at subzero 20 DEG C is up to 102 MPa*m<1 / 2>, and for the fatigue crack growth rate, when deltak is equal to 13.5 MPa*m<1 / 2>, da / dn is as low as 11 m / Gc.

Description

technical field [0001] The invention belongs to the production technical field of steel rails, and in particular relates to a production method for reducing the fatigue crack growth rate of bainite steel rails. Background technique [0002] Rail rolling contact fatigue (RCF) is a common problem in the world's railway transportation. It not only affects the safety of railway transportation, but also shortens the service life of the rail and increases the maintenance cost of the line. Aiming at the rolling contact fatigue damage of rails, the railway transportation departments of various countries have carried out a lot of research, mainly including the research of damage mechanism, the research of new anti-contact fatigue rail materials and the research of rail grinding technology. In terms of research on new rail materials, bainitic steel is known as "the rail steel of the 21st century" for its excellent strength and toughness. The United States, Germany, Japan and other co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/06B22D11/16C21D9/04C21D8/00
CPCB22D11/009B22D11/16C21C7/0087C21C7/06C21D8/005C21D9/04C21D2211/002
Inventor 徐志东朱敏周剑华郑建国吴杰费俊杰王瑞敏叶途明苏尚飞
Owner 武汉钢铁有限公司
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