Methods of eliminating central shrinkage cavity and controlling central segregation of high carbon steel with 280mm×320mm section

Abstract

The invention discloses a method for eliminating central shrinkage cavity and controlling central segregation of high-carbon steel with a section of 280mm×320mm. The secondary cooling mode of continuous casting adopts a weak cooling mode, and the relationship between the reduction amount of the machine frame under light reduction and the solid phase ratio fs at the center of the slab is as follows: : When 0≤fs<0.55, the reduction is 0mm; when 0.55≤fs<0.70, the single-roll reduction is 2.0mm; when 0.7≤fs≤1, the single-roll reduction is 4~5mm; After solidification, the core temperature is lower than the solidification temperature of 110°C and the single-roll reduction is 4~5mm; when the core temperature is lower than the solidification temperature of 150°C after solidification, the single-roll reduction is 2mm; The internal temperature is lower than the solidification temperature of 180°C and the single roll reduction is 0mm. This method controls the reduction amount through the change of the solid phase ratio in the center of the slab and the temperature of the core of the slab after solidification, and eliminates the central shrinkage cavity. 0.5 level, center shrinkage cavity 0 level.

Description

technical field [0001] The invention relates to a continuous casting process, which can eliminate the central shrinkage cavity of the high-carbon steel with a rectangular billet with a large cross-section by dynamic light reduction, and effectively improve the center segregation and center porosity of the cast billet, and belongs to the continuous casting technical field of the metallurgical industry. Background technique [0002] For large-section high-carbon steel with a side length greater than 200 mm (including rectangles), the theory of central segregation is mainly the "solidification crystal bridge" theory. The shape of the end of the liquid-phase cavity inside the high-carbon steel slab is very sharp. Due to the accumulation of solute, the solute concentration at the tip of the liquid-phase cavity is very high. Sealing the tip of the liquid phase hole blocks the interdiffusion between the tip and other liquid phases, thus forming a solute-rich "small ingot" structure...

AI Technical Summary

Problems solved by technology

[0003] In order to solve the above slab production problems, the present invention provides a high-carbon steel rectangular slab continuous casting production process that can significantly eliminate the center shrinkage cavity and reduce defects such as center segregation and center porosity, and specifically proposes a high-carbon steel with a cross-section of 280mm×320mm The method of eliminating center shrinkage cavity and controlling center segregation. In this method, the secondary cooling of continuous casting adopts the weak cooling mode. When the solid phase ratio fs in the center of the slab is ≥ 0.55 and the core temperature of the slab is lower than 180°C after the slab solidifies Implement light reduction to solve defects such as shrinkage cavity and center segregation in the core of the slab

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