Capped tundish bottom permeable ring and tundish slag tapping control method using capped tundish bottom permeable ring

Abstract

The invention discloses a capped tundish bottom permeable ring and belongs to the technical field of steel continuous casting. A device is arranged around a tundish pocket block. The permeable ring isof a cylindrical structure. The upper end face of the permeable ring is in an annulus shape. The value of 1.5 times of maximum section span of the tundish pocket block is less than or equal to the radius of the annulus of the upper end face which is less than or equal to two times of maximum section span of the tundish pocket block, and the height of the permeable ring is equal to the height of the tundish bottom. The slag tapping control method comprises the steps that (1) the capped tundish bottom permeable ring communicates with an air blowing device; (2) at the last tundish pouring stage,when the ratio of the molten steel liquid level height in the tundish to the tundish height is 1:4-5, gas is pumped into the tundish through the permeable ring, a circular convex area with molten steel being exposed is formed at a steel slag interface of the upper portion of a tundish steel tapping hole, and tundish slag tapping is controlled; and (3) after tundish pouring is stopped, the gas isstopped being pumped in. Slag tapping caused by conflux vortex can be eliminated, slag tapping caused by drainage sunken pit is effectively suppressed, the molten steel pouring remain in the tundish is reduced, and the molten steel yield is increased.

Description

technical field [0001] The invention belongs to the technical field of continuous casting of iron and steel, and in particular relates to a breathable ring at the bottom of a tundish with a cover and a method for controlling slag in the tundish. Background technique [0002] The slag control of the tundish in the continuous casting process has always been one of the problems that plague the production of economical and clean steel. At the end of tundish pouring, as the tundish liquid level drops, tundish slag caused by confluence vortices and drainage sinkholes will not only reduce the cleanliness of the slab, but also easily cause accidents such as breakouts. At present, the tundish steel retention operation is generally adopted, that is, a large amount of molten steel is retained in the tundish by techniques such as tundish weighing to prevent slag from the tundish, which will cause a large amount of molten steel in the tundish to be poured and reduce the yield of molten s...

AI Technical Summary

Problems solved by technology

This patent is mainly aimed at the problem of removing inclusions. This patent has the following deficiencies: the purpose of this patent is to remove the inclusions in the molten steel during the casting process of the tundish, and it does not consider solving the problem of slag at the end of the casting process of the tundish; it does not clearly provide The pressure control parameter of argon blowing is difficult to control the pressure of argon blowing in actual production; the flow rate of blowing is controlled based on the slight fluctuation of the liquid steel level, which increases the difficulty of manual operation control; it stops immediately after the ladle stops pouring Blowing argon can not suppress the slag phenomenon in the tundish that occurs at the end of the tundish pouring

The patent has the following deficiencies: the patent is mainly aimed at the cleaning of molten steel in the upper nozzle area of ​​the tundish, and promotes the floating and removal of inclusions; but because there is no clear flow control parameter, the effect of removing inclusions is difficult to guarantee; the diameter of the ceramic venting rod is too small , is not conducive to gas circulation, and cannot effectively prevent the problem of vortex (vortex) slag entrainment; the influence of drainage sinkholes on ladle slag is not considered, and control measures cannot be proposed for slag caused by drainage sinkholes, and there is no fundamental solution The problem of slag in the tundish; the number of breathable ceramic rods is too large and the length is too long, and the production cost of the nozzle seat brick is high; the argon blowing in the whole pouring process of the tundish is too expensive, and the argon blowing for a long time will inevitably lead to a drop in the temperature of the molten steel large, making it difficult to achieve low superheat steady pouring in the tundish; large-scale production of this process is difficult to apply

This patent has the following disadvantages: large air blowing time is long, the cost is high, and the temperature drop of molten steel in the tundish is large, which is not conducive to the low superheat steady state pouring of the tundish

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