Method for controlling center porosity of large section heavy rail steel casting blank

A technology of center loose, heavy rail steel, applied in the field of iron and steel metallurgy, can solve the problems of shrinkage porosity and segregation, and achieve the effects of center porosity control, shrinkage elimination, and improvement of nucleation rate

Inactive Publication Date: 2016-01-06
PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, some key specific technologies for the control of porosity in the center of heavy rail steel continuous casting slabs with large cross-sections (320mm×410mm) have not been involved.
[0005] Chinese patent CN102806330A discloses a method for improving the internal quality of continuous casting slabs with thick and large sections, which can solve the problems of shrinkage cavity porosity and segregation in the center of continuous casting slabs with medium and large sections in the prior art

Method used

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Examples

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Effect test

Embodiment 1

[0031] In this embodiment, a steelmaking plant adopts the technical method of the present invention to produce large-section (320mm×410mm) heavy rail steel U75V continuous casting slabs. The actual control of the production process is as follows: after the vacuum treatment, the exit temperature is 56°C-65°C higher than the liquidus temperature, and the exit temperature of the first heat of the tundish is 74°C. The actual superheat control range of the tundish is 24°C to 33°C, with an average of 30°C. During the pouring process, the normal casting speed is controlled at 0.68m / min~0.72m / min, and the ratio of 0.71m / min (constant speed pouring) is up to 81.1%. The actual depression at the end of solidification is 17.2mm. The stirring intensity of the electromagnetic stirring of the crystallizer is set to 300A, and the stirring frequency is 2.4Hz; the stirring intensity of the electromagnetic stirring at the end of solidification is set to 350A, and the stirring frequency is 7.0Hz...

Embodiment 2

[0034] This embodiment is that a steelmaking plant adopts the technical method of the present invention to produce large-section (320mm×410mm) heavy rail steel U71Mn continuous casting slabs. The actual control of the production process is as follows: after the vacuum treatment, the exit temperature is 57°C to 67°C higher than the liquidus temperature, and the exit temperature of the first batch of tundish is 73°C. The actual superheat control range of the tundish is 26°C to 35°C, with an average of 31°C. During the pouring process, the normal casting speed is controlled at 0.68m / min~0.71m / min, and the ratio of 0.70m / min (constant speed pouring) is up to 77.7%. The actual depression at the end of solidification is 16.8mm. The stirring intensity of the electromagnetic stirring of the crystallizer is set to 400A, and the stirring frequency is 2.4Hz; the stirring intensity of the electromagnetic stirring at the end of solidification is set to 350A, and the stirring frequency is ...

Embodiment 3

[0037] This embodiment is that a steelmaking plant adopts the technical method of the present invention to produce large-section (320mm×410mm) heavy rail steel U78CrV continuous casting slabs. The actual control of the production process is as follows: after the vacuum treatment, the outbound temperature is 57°C to 66°C higher than the liquidus temperature, and the outbound temperature for the first heat of the tundish is 74°C. The actual superheat control range of the tundish is 26°C to 33°C, with an average of 31°C. During the pouring process, the normal casting speed is controlled at 0.69m / min~0.71m / min, and the ratio of 0.70m / min (constant speed pouring) is up to 81.8%. The actual depression at the end of solidification is 17.5mm. The stirring intensity of the electromagnetic stirring of the crystallizer is set to 350A, and the stirring frequency is 2.4Hz; the stirring intensity of the electromagnetic stirring at the solidification end is set to 350A, and the stirring fre...

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Abstract

The invention relates to the technical field of ferrous metallurgy, in particular to a method for controlling the center porosity of a large section heavy rail steel casting blank. The method comprises the following steps of controlling the superheat degree of medium-package molten steel; controlling the pulling speed in the normal pouring process; pressing down the final solidification end in the pouring process; setting the stirring strength and stirring frequency of electromagnetic stirring of a crystallizer; setting the stirring strength and stirring frequency of electromagnetic stirring at the final solidification end; controlling the cooling water yield and the secondary cooling specific water yield of the crystallizer. The center porosity of the large section heavy rail steel casting blank produced by adopting the method can be effectively controlled, and the remaining internal quality of the casting blank can be effectively guaranteed.

Description

technical field [0001] The invention relates to the technical field of iron and steel metallurgy, in particular to a method for controlling looseness in the center of a large-section heavy rail steel slab. Background technique [0002] Steel rails are the main components of railway tracks. During railway transportation, to provide effective support and guidance for locomotives, they need to bear huge vertical pressure from wheels. Based on the development needs of my country's infrastructure construction, railway transportation is developing at a rapid speed, and it is becoming more and more high-speed and heavy-duty. The size of rails is also gradually increasing. In order to reduce welded joints and ensure higher integrity of railway rails, the length of large-size rails is also increasing. The rolling of large-size and long-length rails with smaller cross-section slabs undoubtedly requires longer slab lengths, which requires a major transformation of subsequent heat trea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/18
Inventor 陈亮李红光陈天明
Owner PANZHIHUA IRON & STEEL RES INST OF PANGANG GROUP
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