Continuous casting crystallizer covering slag special for extra-thick slab peritectic steel and preparation method thereof

Abstract

The invention discloses continuous casting crystallizer covering slag special for extra-thick slab peritectic steel and a preparation method thereof. In the covering slag, a peritectic reaction is performed in the process of solidifying the peritectic steel, and the overquick or overlarge volume contraction of the peritectic steel leads to the surface quality problems such as casting blank cracks, and causes dangers in a continuous casting process. In consideration of the characteristics of the peritectic steel, the covering slag for the extra-thick slab peritectic steel shall be cooled slowly and has higher alkalinity and melting points so as to increase the heat resistance of a slag membrane of the covering slag, reduce the speed of transferring heat outwards by casting blanks, and increase the uniformity of heat transfer.

Description

technical field [0001] The invention belongs to the technical field of steel-making auxiliary materials, and in particular relates to a mold slag for continuous casting molds specially used for extra-thick slab peritectic steel and a preparation method thereof. technical background [0002] The extra-thick slab continuous casting machine refers to the slab continuous casting machine that can cast slab thickness ≥ 350mm. Due to the high requirements for the compression ratio of extra-thick steel plate products, in fact, the slab thickness that the extra-thick slab continuous casting machine can produce Should reach about 400mm. [0003] With the development of shipbuilding, boilers, high-pressure vessels, nuclear energy, armor, and heavy equipment manufacturing worldwide, the demand for extra-thick plates is also increasing. Thick steel plates can no longer meet the needs of the market. Therefore, as the "world steel base", major domestic steel mills have launched extra-thi...

AI Technical Summary

Problems solved by technology

Due to the large cross-section and long solidification time of extra-thick slabs, center porosity and segregation are prone to occur inside. In order to ensure better internal quality of cast slabs, the casting speed is usually low, but the mold slag consumption is higher when the casting speed is low. Large, it may cause defects such as pits and depressions. At the same time, due to the low casting speed, the slab stays in the mold for a long time, and the temperature of the slab after it exits the mold is low, and the straightening in the brittle temperature zone It is easy to have defects such as transverse cracks at the vibration marks and corner cracks at the corners of the slab

On the other hand: casting difficulty caused by peritectic reaction

Peritectic steel generally refers to a type of steel with a carbon content of 0.08% to 0.18% in molten steel. Due to the peritectic reaction in the solidification process of this type of steel, coupled with the large section of the extra-thick slab continuous casting , under the conditions of large volume shrinkage and linear shrinkage due to peritectic reaction, it is easy to produce uneven shrinkage of the primary solidified shell, which affects the uniform distribution of the mold slag film, which in turn affects the uniformity of heat transfer and the lubricating performance of the mold slag , may produce thermal stress cracks and large friction caused by poor lubrication.

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