Method for improving internal quality of continuous casting and submerged nozzle for implementing method

Abstract

The invention relates to a method for improving the internal quality of a continuous casting and a submerged nozzle for implementing the method. The submerged nozzle mainly comprises a long-barrel flat annular body submerged nozzle body with the bottom sealed, two arc surfaces at the upper end of the bottom of the nozzle are provided with symmetrical side holes; the two opposite side surfaces and hollow surfaces respectively arranged at the periphery are connected in a closing way to form an integrated feeding guide pipe; each hollow surface is inclined downward and extends while a certain distance is kept with each side surface of the nozzle body, thus all the feeding guide pipe are communicated at the bottom and form an exit section at the bottom of the nozzle body. In a continuous casting process, granular or bead-like, piece-like and strap-like part steel or iron product is continuously fed from the feeding guide pipes of the submerged nozzle and creeps down to the center of a molten pool of a crystallizer, degree of superheat of molten steel can be reduced, the cooling speed at the center is increased, formation of a central isometric crystal is promoted, enrichment and segregation of solute element at the center of a cast blank are prevented, solidification structure at the center of the cast blank is effectively optimized, and the density at the center of the cast blank is strengthened.

Description

technical field [0001] The invention belongs to the technical field of continuous casting of steel, and mainly relates to measures for improving internal quality defects of continuous casting slabs and an accessory device. Background technique [0002] Continuous casting of steel is a process in which molten steel continuously transfers and releases heat in a continuous state, and gradually solidifies into a billet of a certain shape. During the transformation process of steel from liquid to solid state, various surface and internal quality defects are always unavoidable due to the external thermal stress coupling effect and its own solidification shrinkage characteristics. With the continuous improvement of continuous casting technology and control level, the surface quality of the slab has been greatly improved, and those residual surface quality defects can also be removed by surface grinding. Therefore, the current development of continuous casting technology The most i...

AI Technical Summary

Problems solved by technology

Since the rare earth wires fed into the crystallizer usually need to be evenly distributed in the mold under the impact of the flow field, and the addition amount is very limited, it has very little influence on the solidification structure and density of the slab center, and the effect of improving the internal quality of the slab very not obvious

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