RU71413U1 - FIRE-RESISTANT COOKING TANK FOR ACCUMULATION OF LIQUID ELECTRIC SLAG METAL - Google Patents

Abstract

The utility model relates to special electrometallurgy, in particular to installations of electroslag remelting and metal casting. The proposed refractory crucible as well as the analogue contains: a metal body; installed in the bottom of the case, a water-cooled hearth electrode; a cylindrical shell mounted on a layer of bulk refractory material; laid between the inner wall of the crucible body and the cylindrical shell, a compacted layer of loose refractory material, bonded on top with a layer of liquid glass. But unlike the analogue, the proposed refractory crucible additionally contains at least one protective layer of refractory slag deposited during melting in the crucible of slag and metal, on the bottom, on the inner surface of the shell and on the upper surface of the bulk refractory material of the crucible. In the proposed design of the refractory crucible, the cylindrical shell may be made of several shell rings mounted on top of each other. Or, for example, a cylindrical shell may be made of a steel pipe or several steel shell rings.

1 n.a.s. and 2 z.p. f-ly, 1 ill.

Description

The utility model relates to special electrometallurgy, in particular to installations of electroslag remelting and metal casting.

The well-known "Method of manufacturing a refractory crucible" according to the description of the invention to the patent of the Russian Federation No. 2246670, IPC class 7 F27B 14/00, published on 02.20.2005 in Bull. No. 6 (1).

This method involves sequentially stuffing the bottom of the crucible and its wall with layers consisting of regular refractory materials and a material from a reactive mixture of exothermic composition. At the same time, stuffing and vibration ramming of the crucible layers is carried out using stationary and two movable templates, which are sequentially installed on the bottom and the semi-finished product of the two-layer bottom of the crucible.

In the process of the final operation, high-temperature firing of the obtained semi-finished product is carried out, including slow heating of the crucible according to a given schedule to a temperature of 850-950 ° C for 4-6 hours with a heating rate of 2-8 deg / min., Then at a rate of 10-15 deg / min accelerate heating to a temperature of the melt, which provides both ordinary diffuse sintering and welding-synthesis of refractory materials forming a multilayer structure of the crucible bottom and its wall.

The proposed technology for the manufacture of the crucible provides a significant 1.5-2 times or more compared with the known technologies, an increase in the life of the crucible and the melting furnace as a whole. This is achieved due to the high erosion and corrosion resistance to the effects of chemically active and molten media of the synthesized ceramic material of the crucible, its low porosity and non-wettability to the molten metal.

Fine metal powder of aluminum (and / or magnesium, and / or an alloy of aluminum with magnesium, and / or titanium, and / or zirconium) is used as a metal reducing agent, and an oxidizing agent is used

finely divided shungite and / or oxides of elements such as silicon (and / or magnesium, and / or titanium, and / or iron, and / or chromium, and / or manganese).

However, this refractory crucible when used in installations for electroslag remelting and metal casting has a number of design drawbacks, namely:

1. for example, when using iron or silicon oxides in the lining, the lining composition of the crucible becomes less heat-resistant than just a lining made of magnesium oxide, widely used in crucibles;

2. in addition, during electroslag remelting and accumulation of electroslag metal in a crucible with a lining in which chromium oxides are present, it is not allowed according to the technological parameters, since chromium is reduced from oxides and components of the slag and goes into the metal melt, which is categorically not allowed;

3. a protective layer of liquid glass deposited on the upper end surface of the crucible under the influence of alternating temperature expansion-compression compresses rather quickly and crumbles, and not loose-bound bulk refractory material spills out from the top of the crucible when the crucible overturns when the metal is drained from the crucible, and later internal cavities are formed in the crucible, into which liquid metal inevitably penetrates from the crucible melt and, as a result, shortens the electric current to the outer wall of the crucible, which leading to failure of the crucible.

The aim in the development of the proposed utility model is to create an effective design of a refractory crucible for accumulating liquid electroslag metal for electroslag remelting and casting plants.

The specified goal and technical result are implemented as follows.

The proposed refractory crucible as well as the analogue contains: a metal body; a water-cooled hearth electrode installed in the bottom of the case; mounted on a layer of bulk refractory material on the bottom of the body, made of refractory material, a cylindrical shell; laid between the inner wall of the crucible body and the cylindrical shell, a compacted layer of loose refractory material, bonded from above with a layer of liquid glass solution.

But unlike the analogue, the proposed refractory crucible contains

additionally at least one protective layer of refractory slag deposited during melting in the crucible of slag and metal, on the bottom, on the inner surface of the shell and the upper surface of the bulk refractory material of the crucible.

In the proposed design of the refractory crucible, the cylindrical shell may be made of several shell rings mounted on top of each other. Or, for example, a cylindrical shell may be made of a steel pipe or several steel shell rings.

As a close analogue of the proposed refractory crucible for the accumulation of liquid electroslag metal, you can take the technical solution according to the patent of the Russian Federation No. 246670 (1).

The drawing shows the design of the proposed refractory crucible for the accumulation of electroslag metal.

The proposed refractory crucible consists of the following structural units, parts and materials.

A water-cooled hearth electrode 2 is installed in the steel body 1 in its bottom. A layer of loose refractory material 3 is tightly laid on the bottom of the body 1 and around the hearth electrode 2, and a cylindrical shell 4 made, for example, of refractory material, is installed coaxially with the vertical axis of the crucible body 1. . When this shell 4 can be made of several rings, shells mounted on top of each other. In the proposed design of the refractory crucible, the shell 4 can be made not only of refractory material, but also of a solid steel pipe or several steel shell rings.

A layer of loose refractory material 3 is also laid between the inner wall of the crucible body 1 and the outer surface of the shell 4. A guide shell 5 is mounted on the upper end wall of the crucible body 1, designed to direct the flow of liquid slag and metal into the crucible drain 6.

On the outer upper part of the crucible body 1, under the drain nozzle 6, the axis of rotation of the crucible 7 is strengthened, around which the crucible rotates when the molten metal and slag from the crucible are drained. On the bottom of the melting tank in the cavity of the shell 4, on the inner surface of the shell 4 and on the upper surface of the loose refractory material 3 and on the drain nozzle 6, a skull 8 is formed (applied) (slag layer of refractory components of the slag and lining),

obtained in the process of the first melting in a crucible of slag and metal. In subsequent melts, the skull 8 continues only to be hardened due to the refractory components of the slag at the lining.

The proposed refractory crucible works as follows. Already at the first electroslag melting of the metal, the entire inner surface of the shell 4 is covered with a layer of skull 8, and to apply the skull 8 on the upper surface of the loose refractory material 3, melting is continued until the liquid slag overflows the entire inner volume of the shell 4, and then fills and the whole the upper surface of the bulk refractory material 3. And after that, the entire melt of slag and metal is drained from the crucible.

And on the above-mentioned surfaces of the crucible, a protective layer of the skull is already applied (formed).

If in the design of the refractory crucible the shell 4 is made of a steel pipe or several steel shell rings, then during the first electroslag melting, the material of the steel pipe or steel shell rings is smelted, and sintered with high temperature is formed on the inner surface of the tank formed from loose refractory material 3 (refractory) components of the slag heat-resistant layer of the skull 8, and during subsequent melting, this strong protective layer is preserved.

Thus, the proposed design of the refractory crucible for accumulating liquid electroslag metal in comparison with the analogue has the following advantages:

1. after the first melting on the inner surfaces of the crucible, a protective layer of a skull is formed of refractory components of the slag and lining, which prevent the pouring of loose refractory material from the cavity of the crucible;

2. Thanks to the protective layer on the inner cavity of the crucible, formed from the refractory components of the slag and the lining, the life of the crucible doubles.

A prototype of the proposed refractory crucible for the accumulation of liquid electroslag metal was made and tested with positive results in February-April 2007 in Omsk.

The source of information.

1. "A method of manufacturing a refractory crucible" according to the description of the invention to the patent of the Russian Federation No. 2266670, IPC class 7 F27B 14/10, published on 02/20/2005 Bull. No. 6.

Claims (2)

1. Refractory crucible for glowing liquid electroslag metal, containing a metal body; a water-cooled hearth electrode installed in the bottom of the case; mounted on a layer of bulk refractory material on the bottom of the body, made of refractory material, a cylindrical shell; laid between the inner wall of the crucible body and the cylindrical shell, a compacted layer of loose refractory material bonded on top with a liquid glass solution, characterized in that it further comprises at least one protective layer of refractory slag deposited on the bottom during melting of the slag and metal in the crucible , on the inner surface of the shell and the upper surface of the bulk refractory material of the crucible. 2. The refractory crucible according to claim 1, characterized in that the cylindrical shell is made of several shell rings mounted on top of each other.