RU2460608C1 - "gas dome" device for metal purification and pouring - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy. Device includes ladle (1) with bottom pouring shell (2) and dome (3) with holes (4), which is located above bottom pouring shell. Open part of dome (3) is fixed at bottom of ladle (1) or at bottom of ladle (1) and its wall. In upper part of dome (3) there is branch pipe (5) connecting the cavity of dome (3) by means of valve (6) to compressed gas source or to atmosphere. In dome (3) cavity above pouring shell (2) there located is shutoff fire-proof element (7) the density of which is less than density of liquid metal.

EFFECT: simplifying the device design, improving metal pouring reliability without stopper and damper, and improving metal quality.

2 dwg

Description

The invention relates to the field of metallurgy, to locking and sliding devices for pouring liquid metal from a ladle.

Known devices for casting metal (steel) - stoppers and gates, described, for example, in the book "Theory and Practice of Continuous Casting of Workpieces", Smirnov AN and others, Donetsk, 2000, p. 71, 159, have the following disadvantages.

During stop casting, a fairly quick mechanical breakdown of the stopper occurs due to its wear in the area of the slag belt and head, as well as breakage in the area of its fastening with the stopper bar. In addition, there is often warping of the fork connecting the rod and the locking mechanism.

The gate casting contains a complicated start-up scheme due to backfill of the gate gate channel, the reason for which is a significant lengthening of the steel outlet of the ladle to the mold (mold), which contributes to channel overgrowth with non-metallic and slag inclusions, violation of the casting regime and an increase in the number of rejects. Air leakage between the plates of the slide gate reduces the quality of the metal. The slide gate has a complex structure and high cost.

A common drawback of these casting methods is the need to use mechanisms that, experiencing the high temperature of steel casting, often break down, stopping the production process. In addition, due to the lack of refining of steel, there is no improvement in its quality, but, on the contrary, there is a decrease until the marriage is rejected and the machine for continuous casting of steel billets (CCM) is stopped. As a result of this, steel production decreases and the cost of casting increases.

The prototype of the invention is a device for casting metal from a ladle containing a pouring cup protruding into the bucket and an additional outer cup concentrically located above it with slots, the slots being made with a height equal to 0.3-0.6 from the protruding part of the main casting cup, and the cavity between glasses connected to the pneumatic system and the slide gate - ed. testimonial. USSR No. 727326, B22D 41/08, 1980

The disadvantages of this device are: the complexity of the design, the lack of reliability of the slide gate, gas leakage through the opening of the nozzle and between the plates of the slide gate, the large specific consumption of metal for casting and, as a result, the relatively high cost of casting.

The technical problem solved by the invention is to simplify the design of the device, increase the reliability of casting metal without stopper and gate, improve the quality of metal and reduce the cost of casting.

This problem is solved in a device for refining and casting metal, containing a bucket and a cap (gas cap) with holes - on the bottom of the bucket, located concentrically above the bottom pouring cup, while the cap with the open part is fixed on the bottom of the bucket or on the bottom of the bucket and its wall, forming a pocket (gas pocket), a pipe is made in the upper part of the cap connecting the cap cavity with a source of compressed gas or atmosphere using a valve; in the cap cavity above the pouring cup, the shut-off a refractory element whose density is less than the density of a liquid metal.

In the particular case of the invention, the shut-off refractory element is made in the form of a refractory ball.

The essence of the invention lies in the fact that instead of expensive, complex and having a very limited service life devices for casting metal from a ladle - stopper and gate, a simple device is created - a cap, which is a combined device: constipation - dispenser - lance.

Figure 1 shows a longitudinal section of a device containing a cap, figure 2 is a longitudinal section of a device containing a pocket.

The devices of FIGS. 1 and 2 contain a bucket 1, in the bottom of which a pouring cup 2 is installed, over which a cap 3 with holes 4 at its base is concentrically mounted on the bottom of the bucket with the open part. A nozzle 5 is attached to the upper part of the cap 3; it connects the cavity of the cap 3 through the valve 6 with a source of compressed gas or with the atmosphere. In the cavity of the cap 3 is in a free state locking element, made in the form of a refractory ball 7.

To increase the life of the pipe 5 by reducing its contact with liquid metal, the open part of the cap 3 can be fixed on the bottom of the bucket 1 and its wall with the formation of a pocket 8 - figure 2.

The device operates as follows.

Liquid metal enters the capacity of the bucket 1 and flows through the openings 4 into the cavity of the cap 3 when the valve 6 is closed, washing the base of the shut-off refractory ball 7, closing the filling opening of the cup 2 and locking the air in the cavity of the cap 3. Ball 7 is immersed under air pressure into liquid metal. With increasing level of metal in the capacity of the bucket 1 increases the metallostatic pressure on the locking ball 7, and the air pressure in the cavity of the cap 3 increases. Also, the heating of the air from the heat of the liquid metal contributes to the increase in pressure. An increase in gas temperature for every 273 ° C increases the pressure in the cavity of the cap 3 by about 1 atm. The excess air pressure in the cap 3 at 1500-1600 ° C is approximately 5 atm, acting on the shut-off ball 7. Together with the metallostatic pressure, the gas pressure compresses the shut-off ball 7, reliably closing the filling opening of the cup 2. With it, the magnitude of the lifting Archimedean force is small, those. insufficient to lift the ball 7 above the hole of the glass 2, since the ball 7 is immersed in the melt only with its base.

After filling the bucket 1 with liquid metal, open the valve 6, reducing the pressure in the cavity of the cap 3 to atmospheric level. Liquid metal under the action of metallostatic pressure rushes through the holes 4 into the cavity of the cap 3; at the same time, the magnitude of the Archimedean force increases, pushing the floating locking ball 7, on the base of which the upward pressure of the metal flow acts. As a result, under the influence of these forces, the locking ball 7 floats, freeing the opening of the glass 2, and the casting of metal begins.

To adjust the pouring of liquid metal, the gas pressure in the cavity of the cap 3 is changed using valve 6. When the pressure in the cap 3 is increased, the reaction of the metal-static pressure is increased, thereby reducing the height of the liquid metal column in the cavity of this device and reducing the rate of pouring of liquid metal until the filling hole is closed cup 2 ball 7, stop casting.

When reducing the gas pressure in the cap 3 increase the effect of metallostatic pressure, increasing the rate of casting of liquid metal.

When performing the design with pocket 8, all the described processes do not change, they are similar to the above.

For refining liquid metal, cap 3 is used as a shutter-dispenser and as a lance for purging liquid metal with gas, for example, oxygen and argon. The gas pressure in the cavity of the cap 3 is determined by the formula P >> Ratm. + QH, where q is the density of the liquid metal, N is the height of the liquid metal in the bucket 1. Having received the desired pressure in the cavity of the cap 3, in accordance with the specified formula, refine liquid metal through the holes 4 by sparging the metal with gas, while the ball 7 closes the hole of the pouring cup 2 and performs the function of a complex device - a slide gate.

As a result, the cap, which is a simple reliable device, provides refining of metal and its casting from the ladle, eliminating the use of expensive, complex and unreliable devices - stopper and gate.

The use of the device can significantly simplify the process of production and casting of steel, increase the utilization of production capacity - KIMP and reduce the cost of casting and rolling.

Claims (2)

1. A device for refining and casting metal, containing a ladle with a bottom casting cup and a cap with holes located above the bottom casting cup, characterized in that the cap is open part mounted on the bottom of the bucket or on the bottom of the bucket and its wall, in the upper part of the cap is made a pipe connecting the cap cavity by means of a valve with a source of compressed gas or atmosphere, while a shut-off refractory is located in the cap cavity above the bottom pouring nozzle with the possibility of closing its pouring hole th element whose density is less than the density of the molten metal. 2. The device according to claim 1, characterized in that the shut-off refractory element is made in the form of a refractory ball.

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