Submersed nozzle for high-casting-speed continuous casting crystallizer

Abstract

The invention relates to a submersed nozzle for a high-casting-speed continuous casting crystallizer. The submersed nozzle comprises a side wall and a back cover; slag lines are arranged on the outer surface of the side wall; the back cover is mounted at the lower end of the side wall; the side wall forms an inner cavity with an upper opening in the vertical direction; more than one side hole are formed on the side wall and are positioned close to the upper part of the back cover; the side holes are communicated with the inner cavity of the side wall; the upper surface of the bottom of the inner cavity of the side wall is lower than the lower edge of any one side hole, so that the bottom of the inner cavity of the side wall is concave; and steel liquid flows in the inner cavity of the side wall from the upper opening, impacts the bottom of the inner cavity of the side wall, bounces and flows out from the side holes of the side wall. By adoption of the technical scheme, the bottom of the inner cavity of the side wall can effectively buffer the speed of the steel liquid, so as to dissipate kinetic energy of the steel liquid considerably, reduce the impact strength of the steel liquid at high casting speed, reduce impact of the steel liquid on the blank shell of the wall surface of a crystallizer as well as interference of the steel liquid with the liquid level, and avoid excessive fluctuation and slag entrapment of the liquid level.

Description

technical field [0001] The invention belongs to the technical field of continuous casting of steel, and in particular relates to a slab and a submerged nozzle of a high-speed continuous casting crystallizer for a bloom continuous casting crystallizer whose section size is greater than 200mm×200mm. Background technique [0002] Continuous casting of steel is the process of continuously cooling molten steel with a certain degree of superheat into a solid billet shell with a certain shape through a water-cooled crystallizer. In the continuous casting process of steel, a very important step is to use refractory materials. The submerged nozzle device continuously injects the molten steel in the tundish into the mold. The submerged nozzle is a refractory sleeve installed at the bottom of the tundish and inserted below the liquid level of the mold. Its main function is to prevent secondary oxidation of the molten steel. , nitriding, and splashing, while avoiding slag rolling on the...

AI Technical Summary

Problems solved by technology

The above characteristics lead to the following unfavorable factors during pouring of the submerged nozzle: First, because the bottom surface of the nozzle inner cavity is a smooth plane or inclined surface, after the molten steel hits the bottom surface, it will cause a relatively strong impact rebound, regardless of whether the bottom of the nozzle is convex. , flat bottom or concave bottom, the buffering and kinetic energy consumption of molten steel are relatively small, and the impact of molten steel is strong when pouring at high casting speed, so that the outlet stream has a greater impact on the primary solidified shell, and at the same time, the liquid level fluctuates violently , which is not conducive to the normal growth of the billet shell; secondly, because the wall surface around the side hole of the nozzle is also a smooth plane or slope, the contact area between the side hole wall surface and the molten steel is limited, and the gap between the side wall and the molten steel cannot be well utilized. The friction effect between them reduces the impact kinetic energy of the molten steel, which makes the impact of the molten steel on the billet shell and the liquid surface greater, resulting in quality problems of the billet. At the same time, the stability of the stream flowing out of the side hole is also poor, which is not conducive to the billet shell uniformity of growth

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