Method for eliminating central looseness of casting blank and improving density of casting blank

Abstract

The invention discloses a method for eliminating central looseness of a casting blank and improving density of the casting blank. The method includes arranging a plurality of sets of hold-down rollers in the rear of the exit of a fan-shaped section of a continuous casting machine and allowing the linear speed of the hold-down rollers to be synchronous with the casting speed of the continuous casting machine. The hold-down rollers are arranged in the rear of the fan-shaped section of the continuous casting machine, so that deformation on the middle portion of the casting blank is larger than that of the surface by changing set positions of the hold-down rollers, central gaps of the casting blank are eliminated, the problem about central looseness of the casting blank is solved, and the central density of the casting blank is improved; the forming process of the casting blank and the matching relation between the hold-down rollers and hold-down quantities are controlled, so that surface cracks of the casting blank can be effectively prevented, densification in central tissue can be improved, quality of the interior of the casting blank can be improved, and control over the quality of the surface of the casting blank can be realized.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for eliminating porosity in the center of a slab and improving the density of a slab. Background technique [0002] The continuous casting process is accompanied by the solidification heat transfer process, and shrinkage is an inevitable phenomenon accompanied by the solidification process. If the solidification shrinkage can be replenished in time by the liquid phase, the formation of porosity can be prevented. Whether the feeding channel is unblocked during the solidification process is the key factor determining the formation of porosity. During the solidification process, the billet has to go through the process from the liquid phase to the two-phase region and then to the solid phase. The feeding channel of the liquid phase is unblocked, and no porosity will be formed in the liquid phase. In the two-phase region, due to the two sides of the billet Th...

AI Technical Summary

Problems solved by technology

[0004] Among the above three methods, controlling harmful elements or impurity elements in the smelting process is a very effective method, but the degree of reduction is often limited and the cost is relatively high

Electromagnetic stirring technology and low superheat casting technology can reduce central segregation by increasing the proportion of equiaxed grains in the two-phase region of the slab, but molten steel with enriched segregation elements between equiaxed grains will form semi-macro segregation and Loose; In addition, low superheat casting also has the problem of easy blockage of the nozzle, which makes it difficult for inclusions to float up and increases the risk of production accidents

Soft reduction is achieved by applying mechanical pressure to the slab during the solidification process to break the columnar crystals produced during the solidification process, trace back and mix the molten steel enriched in solute elements to eliminate slab center segregation At the same time, the amount of compression formed can make up for the solidification shrinkage of the slab, and can eliminate or reduce the voids or gaps formed inside the slab; although this method can make the interior of the slab more uniform and dense, it can eliminate or reduce the looseness of the center. , but the existing technological means and measures are not only unsatisfactory in eliminating center porosity and improving density, but also have problems such as high production cost, high production risk and increased maintenance, which greatly reduces production and economic benefits

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