Secondary cooling nozzle arranging method for improving surface plasticity of casting blank and secondary cooling control method

A technology of control method and arrangement method, which is applied in the field of metallurgy, can solve the problems of failure to completely eliminate the defects of transverse cracks at the corners of the slab, and the insufficient improvement effect of transverse cracks, and achieve the goal of eliminating crack defects, improving high-temperature plasticity, and inhibiting precipitation behavior Effect

Inactive Publication Date: 2015-05-13
CISDI ENG CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its improvement effect on the transverse cracks deviated from the corner is insufficient, and the transverse crack defects in the corner area of ​​the slab cannot be completely eliminated

Method used

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  • Secondary cooling nozzle arranging method for improving surface plasticity of casting blank and secondary cooling control method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] A steel factory uses a vertical curved continuous casting machine to produce billets with a section of 190mm×1650mm. The steel type is ordinary carbon steel Q235, the casting speed is 1.1m / min, and the specific water volume of the conventional secondary cooling is 0.6L / kg. The layout of the nozzles in the vertical section is transformed, and the wide and narrow secondary cooling circuits in this area are transformed into an independent control mode, and the nozzles are all-water nozzles. After the slab exits the crystallizer, the cooling water flow rate on the wide surface is 25m 3 / h, the flow of cooling water on the narrow side is 8m 3 / h.

[0025] During the production process, the cracks on the surface of the slab were first observed manually, and then the surface cracks of the slab were detected by flame cleaning and hot acid corrosion after the slab was cooled. No cracks were found on the surface of the slab.

Embodiment 2

[0027] A steel factory uses a vertical curved continuous casting machine to produce billets with a cross-section of 230mm×1870mm. The flow of cooling water on the wide surface after the crystallizer is 28m 3 / h, the flow of cooling water on the narrow side is 10m 3 / h.

[0028] After the slab was off-line and cooled, the surface cracks of the slab were detected by hot acid corrosion method, and no crack defects were found on the surface of the slab.

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Abstract

The invention relates to a secondary cooling nozzle arranging method for improving surface plasticity of a casting blank and a secondary cooling control method. In the secondary cooling nozzle arranging method, wide nozzles and narrow nozzles are formed in the vertical section of a continuous casting machine, and the wide nozzles and the narrow nozzles are controlled by independent loops respectively; after a continuous casting blank is discharged from a crystallizer, by the secondary cooling nozzle arranging method, the casting blank is forcibly cooled with the amount of secondary cooling water of 15-40m<3>/ h to rapidly reduce the surface temperature of the casting blank to below 750 DEG C; narrow corner nozzles and wide corner nozzles in a lower area of the vertical section are closed to rapidly raise the surface temperature of the casting blank to about 1100 DEG C, and from the bent section to the horizontal section, a conventional cooling mode is adopted with the amount of the secondary cooling water of 2-10m<3>/ h. In the secondary cooling nozzle arranging method, the changing course of the surface temperature of the casting blank enables the surface tissue of the casting blank to experience once heat treatment, so that the surface tissue of the casting blank is greatly thinned; after rewarming, a dense austenitic tissue is formed on the surface of the casting blank, the precipitation amount of a grain boundary ferrite film is inhibited at the same time, and the high-temperature plasticity of the surface of the casting blank is radically improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and relates to a secondary cooling nozzle arrangement method and a secondary cooling control method for improving the surface plasticity of a slab. Background technique [0002] In the process of continuous casting, surface crack defects of slabs have always troubled metallurgists at home and abroad. Various production enterprises, universities and scientific research institutions have conducted a lot of research work on this problem, and formed control measures suitable for their respective enterprises. , well inhibited the occurrence of crack defects on the surface of the continuous casting slab. [0003] After a lot of research, metallurgists have proposed a conventional method to alleviate the defects of transverse cracks at the corners of microalloyed steels—to avoid the brittle temperature zone of microalloyed steels. This method includes two ideas: "hot operation" and "cold operation". ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/124B22D11/22
Inventor 韩志伟孔意文毛敬华刘强
Owner CISDI ENG CO LTD
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