Arrangement Structure of Submerged Nozzle for Shaped Billet Crystallizer

Abstract

The invention relates to an arrangement structure of submerged nozzles for a special-shaped billet crystallizer. In the special-shaped billet crystallizer, two submerged nozzles are respectively arranged in two triangular areas where the flange of the special-shaped billet and the web intersect and casting is performed simultaneously; the two nozzles The position is axially symmetrical along the vertical line of the web center of the profiled billet; the third holes of each nozzle are opposite and aligned with the center of the web, and the center line between the left and right sides of the third hole coincides with the center line of the web. The holes are distributed axially symmetrically along the centerline of the web. During pouring, the two nozzles are symmetrically arranged in the triangular area of ​​the profiled billet, the holes on the symmetrical sides of the nozzle are aligned with the two ends of the flange, and the third hole is aligned with the center of the web. The submerged nozzle and its arrangement can obviously disperse the impact force of molten steel, improve the thermal center of molten steel, promote the uniformity of temperature and composition in the cross-section of the crystallizer, facilitate the removal of inclusions and reduce cracks and segregation. Quality defects.

Description

technical field [0001] The invention belongs to the submerged nozzle device of the billet continuous casting crystallizer, and mainly relates to the arrangement structure of the submerged nozzle device for the mold of the special-shaped billet on the special-shaped billet. Background technique [0002] Continuous steel casting is the process of continuously cooling molten steel after smelting into a solid billet with a certain shape through a water-cooled copper crystallizer. During this process, the submerged nozzle device made of refractory material is usually used to continuously transport the molten steel in the upper station (tundish) into the crystallizer. The submerged nozzle can isolate the molten steel from the air, prevent the secondary oxidation of the molten steel, and ensure the purity of the molten steel; at the same time, by designing a suitable submerged nozzle structure size, a reasonable, stable and uniform mold flow field can also be obtained , to ensure ...

AI Technical Summary

Problems solved by technology

However, the impact depth of the straight-through nozzle is relatively large, and the thermal center of the molten steel moves downward, which is not conducive to the effective floating of inclusions and the growth of the primary shell. Moreover, the molten steel flowing out of the straight-through nozzle is mainly concentrated in the triangular area, making The temperature and composition of the entire profiled billet vary greatly in the transverse direction, which easily leads to quality defects such as cracks and segregation

The third method is to use a single submerged nozzle to pour in the triangular area on one side of the profiled billet section, which will make the flow field and temperature field of the molten steel in the mold extremely unreasonable, resulting in various surface and internal quality of the billet. Problems occur frequently, and in serious cases, steel leakage accidents may occur

However, the high-temperature molten steel at the outlet of the nozzle can only flow to the longitudinal ends of the web, and the two sides of the flange cannot be supplemented by high-temperature molten steel, so that the temperature and composition of the slab in the transverse direction are quite different. The wall distance of the web is very short, which is prone to "bridge", which is not conducive to the melting and lubrication of mold powder. In addition, in order to make the nozzle fit into the web, the wall thickness of the nozzle is usually reduced, which reduces the service life of the nozzle

[0006] Based on the above reasons, it can be seen that the submerged nozzle and its arrangement and pouring method of the shaped billet crystallizer in the prior art are difficult to fully meet the requirements of the complex section of the shaped billet, and the overall pouring effect is not very ideal.

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