RU2728142C1 - Melting-filling crucible with automatic discharge of melt through channel of siphon type - Google Patents

Abstract

FIELD: foundry.

SUBSTANCE: invention relates to foundry production, particularly, to melting potting crucibles, and can be used in vacuum installations for production of castings from metals and alloys with induction and resistive heating of crucible. Crucible with automatic discharge of melt through channel of siphon type, cavity of which is hydraulically connected to outlet channel, has outlet channel, having U-shape, which makes with crucible integral unit and consists of 2 vertical cavities, first of which for upward flow of metal by its lower part is hydraulically connected to internal bottom part of crucible by means of lower horizontal web, and by its upper part is hydraulically connected by means of upper horizontal web with upper part of second vertical cavity for downflow of metal, which lower end is outlet of crucible, besides, second vertical cavity for descending metal flow is structurally longer than first vertical cavity.

EFFECT: invention improves quality of obtained castings due to prevention of clogging with slag inclusions, and also prolongs crucible life due to absence of moving parts and mechanisms of inclination and rotation.

4 cl, 8 dwg

Description

The invention relates to the field of foundry, namely to the structures of melting and casting crucibles and can be used in vacuum installations for the production of castings from metals and alloys with induction and resistive heating of the crucible with the melt during batch melting and casting.

Known crucible for melting and pouring heat-resistant steels and alloys, containing a melting tank, equipped in the upper part with an extension made in the form of a sock. (Production of castings from non-ferrous metal alloys. Kurdyumov AV, Pikunov MV, Chursin VM, Bibikov EL: Textbook for universities. M. Metallurgy, 1986, S. 83).

Known crucible for a vacuum induction melting and casting installation for casting parts made of heat-resistant steels and alloys, containing a melting vessel equipped in the upper part with an extension made in the form of a drain tank, at the base of which a drain hole is made, while one of the walls of the extension is inclined at an angle β to the base of the melting tank (patent for PM RF No. 119081, IPC F27D 14/10).

Known is a melting and casting crucible containing a body, on which a cover is installed, made in the form of a plate in the form of a segment, the radius of which is equal to the outer radius of the upper part of the body, while the width of the cover is 0.7-1.3 of the outer radius of the upper part of the body, and a through groove is made in the lid, forming a drain hole in contact with the crucible body along the inner radius (patent for PM RF №148383, F27D 14/10).

The disadvantages of the known technical solutions are mechanical units located in a zone with a high temperature for discharging the melt from the crucible through the extension. Other disadvantages of these designs are the increased length of the path of the melt during its flow through the drain cavity, associated with the presence in the crucible of an extension in its upper part, or a cover with an opening, which leads to mixing of the slag into the flow of the poured melt and thus contamination of the castings.

Known crucible vacuum induction melting and casting installation, containing a melting tank, equipped in the upper part with an extension made in the form of a drain tank, at the base of which a drain hole is made, while one of the walls of the extension is inclined at an angle β to the base of the melting vessel (useful model of the Russian Federation No. 119081, IPC F27D 14/10).

The disadvantage of this design is that during the period when the crucible turns to drain, a turbulent flow is formed in it with mixing of slag inclusions into the melt, which are a source of defects in the castings.

Also known is a method of separating slag from metal in a stopper ladle at the end of metal pouring, in which a refractory of regular shape with a density of 3-4 g / cm ^{3 is} placed on the surface of the molten metal in the stopper ladle. The floating refractory is located under the slag layer and at the end of the metal casting it cuts off the slag, excluding it getting into the molds (RF patent for invention №2115510, B22D 41/08, publ. 20.07.1998).

The disadvantage of this method is the contamination of the melt and refractory and insufficient cut-off of the slag.

- металлотрактом выдачи металла, пристыкованным к нему индуктором бегущего магнитного поля, на входе в тракт выбрано углубление, размещенное в зоне действия того же индуктора. В углублении установлена параллельно дну перегородка, образующая полость с постоянным уровнем. Канал выдачи гидравлически соединен с углублением в зоне входного патрубка, а сливное отверстие его расположено на уровне верхнего торца параллельной перегородки (патент на изобретение РФ №2017579, B22D 39/00).The closest technical solution, chosen as a prototype, is a device for casting metal, in a refractory block of which, with

- a metal conduit for the delivery of metal, docked to it by an inductor of a traveling magnetic field, at the entrance to the conduit, a depression is selected, located in the zone of action of the same inductor. In the recess, a partition is installed parallel to the bottom, which forms a cavity with a constant level. The delivery channel is hydraulically connected to the recess in the area of the inlet pipe, and its drain hole is located at the level of the upper end of the parallel partition (RF patent No. 2017579, B22D 39/00).

The disadvantage of the known design is the inconvenience of the location of the drain hole, the short service life of the crucible.

The technical result of the invention is to improve the quality of the resulting castings by preventing clogging by slag and other foreign inclusions present in the melt and penetrating into the casting mold during its pouring, as well as extending the life of the crucible due to the absence of moving parts and the absence of tilt mechanisms and turning.

The technical result is achieved by the fact that the melting and pouring crucible with automatic discharge of the melt through a siphon-type channel, the cavity of which is hydraulically connected to the outlet channel, and the outlet channel, having a U-shape, constitutes a single whole with the crucible and consists of 2 vertical cavities , the first of which (for an upward flow of metal) with its lower part is hydraulically connected to the inner bottom of the crucible by means of a lower horizontal bridge, and its upper part is hydraulically connected by means of an upper horizontal bridge with the upper part of the second vertical cavity (for a descending metal flow), the lower end which is the outlet of the crucible, which allows automatic bottom discharge of the melt when it reaches a fluidity state, and the second vertical cavity (for a downward flow of metal) is structurally longer than the first vertical cavity.

2. The cavity of the siphon-type channel contains technological holes in the crucible wall, arising from the formation of the siphon-type channel, plugged with threaded plugs.

3. The melting-pouring crucible with automatic melt discharge through the siphon-type channel is made of a composite one.

4. A melting and casting crucible with automatic melt discharge through a siphon-type channel, consists of a material that conducts an electric current and has a resistance greater than the resistance of the electrodes supplying current (for example, graphite).

The proposed technical solution is illustrated by schematic drawings.

FIG. 1 shows the design of the crucible, where:

1 - crucible;

2 - loading cavity;

3 - the first vertical cavity (for an ascending metal flow);

4 - lower horizontal crosspiece;

5 - upper horizontal crosspiece;

6 - the second vertical cavity (for a downward flow of metal);

7 - crucible outlet.

FIG. 2 shows a crucible with loaded and not yet molten metal 8.

FIG. 3 shows a crucible with metal melt 9 beginning to appear.

FIG. 4-5 shows a crucible with automatically pouring out melt 9 of metal 8.

FIG. 6 shows a crucible with an automatically interrupted outlet of metal melt 9.

FIG. 7 shows the threaded plugs 10, plugging the technological holes remaining after the formation of the cavity of the siphon-type channel with the integral design of the crucible.

FIG. 8 shows an embodiment of a composite crucible, where horizontal sections A-A and B-B show possible connection lines of the composite parts of the crucible.

Structurally, crucible 1 is a loading cavity 2, with a side siphon, formed in the wall of the crucible 1 itself, a U-shaped channel starting at the bottom of the loading cavity 2, and representing a lower horizontal bridge 4 passing into the first vertical cavity 3 (for rising metal), connected by an upper horizontal bridge 5, with a second vertical cavity 6, (for a downward flow of metal and ending with an outlet 7.

The crucible works as follows.

In the loading cavity 2, crucible 1, the feedstock (metal, alloy) 8 is loaded, intended for melting. When the starting material (metal, alloy) 8 melts, the level of the melt 9 in crucible 1 begins to rise. At the same time, the melt enters the lower horizontal bridge 4 of the siphon U-shaped channel and then, according to the principle of communicating vessels, rises into the first vertical cavity 3 (for an upward flow of metal), overflows along the upper horizontal bridge 5, into the second vertical cavity 6, (for downward flow of metal), forming a U-shaped siphon channel and through the outlet 7 is supplied to its intended purpose (in the casting mold, mold, etc.). Due to the action of gravity, the effect of communicating vessels and the fact that the second vertical cavity 6 (for a downward flow of metal) is longer than the first one, which means that the mass of the melt in it is greater, then this part of the melt carries with it the rest of the melt in the siphon U-shaped channel.

When the level of the melt 9 drops to the level of the suction hole of the lower horizontal bridge 4 of the U-shaped siphon channel, the melt column breaks at the entrance to the U-shaped siphon channel. As a result, slag inclusions located on the surface of the melt mirror cannot penetrate into the siphon channel and remain at the bottom of the loading cavity 2. And subsequently they can be easily removed from there.

Moreover, the melt can pass through the siphon U-shaped channel only when it reaches the state of the required fluidity. Due to the design features of the crucible, the upper part of the melt mirror, as a rule, containing impurities and slags, cannot leave the crucible through the channel due to the rupture of the melt column at the entrance to the siphon channel with an insufficient level of melt at the bottom of the charging cavity and remains at the bottom of the charging cavity. from where it is easily removed.

The proposed technical solution allows, without the use of mechanization means, to carry out automatic discharge of the melt when it reaches optimal fluidity. This avoids too early discharge of the melt with insufficient fluidity for complete casting of the mold or too late discharge of the too overheated melt, which in this case may undergo undesirable structural and chemical transformations. The liquid melt moves through a U-shaped siphon-type channel located in the wall of the crucible itself and having the same temperature as it, which prevents overcooling and crystallization of the melt in the channel. Thanks to the bottom discharge of the melt from the crucible, there is no splashing of the melt and the ingress of slags and other foreign inclusions from the surface of the melt into the casting mold is excluded.

The design of the crucible prevents the ingress of slag and film inclusions present in the liquid metal by separating them from the melt in the crucible itself.

Due to the fact that the melt fills the siphon channel on its own, when it reaches the temperature of optimal fluidity, there is no need for high-precision measurement of the temperature of the melt to determine the exact moment for its discharge from the crucible.

The melting and casting crucible with automatic melt discharge through a siphon-type channel, the cavity of which is hydraulically connected to the outlet channel, can be manufactured in two versions - non-separable and composite.

1. Option of a non-separable crucible with a siphon channel.

Siphon U-shaped channel of a non-separable crucible (Fig. 7), is a drilled cavity in the side wall. The technological holes obtained in this case on the side surface of the crucible are plugged with screw plugs 10. With the screw plugs removed, access to the inside of the channel for cleaning it is possible in case of slag inclusions.

2. Option of a compound crucible with a siphon channel.

Composite crucible with a siphon channel (Fig. 8) where horizontal sections A-A and B-B show possible connection lines of the crucible components. In this case, the crucible is a set of elements with pre-made holes for the pouring cavity and the siphon channel, mounted vertically on top of each other and fastened with threaded fasteners to each other. By combining the number of elements, the crucible height can be changed. This makes it possible to use the crucible for different volumes of the charged charge. The stacked design of the crucible also makes it easier to clean it, and also makes it possible to replace only individual elements in case of damage. Due to the poor wettability of the crucible material by the melt and the tight fit of the structural elements to each other, the penetration of the melt into the joints between the elements is prevented and the tightness of the siphon channel is ensured, which is a prerequisite for the crucible to work. The melting processes, the movement of the melt along the siphon channel and the discharge of the melt are completely analogous to the processes for the one-piece crucible.

The principle of operation of a melting-pouring crucible with automatic discharge of the melt through a siphon-type channel is based on the well-known laws of physics. The melting and casting crucible itself with automatic discharge of the melt through the U-shaped channel of the siphon type is made as a composite or as a whole, from a single mass of graphite, ceramics or metal, using well-known technologies, on standard processing equipment, which indicates the industrial applicability of the proposed technical solutions. In the case of making a crucible from a solid volume of material, the channels are made by drilling and then closing the technological holes formed during drilling with threaded plugs that exit into the outer walls of the crucible or the filling cavity. The screw plugs can be removed if necessary to clean the channels.

The melting and casting crucible can be used both for the case of external heat supply, and for the case of using it as a heater when passing an electric current through it. The melting process will proceed similarly to the case of external heat supply. In this case, the melting and casting crucible is made of a material that conducts an electric current and has a resistance greater than the resistance of the current supplying electrodes (for example, from graphite).

Claims (4)

1. Melting and pouring crucible with automatic discharge of the melt through a siphon-type channel, the cavity of which is hydraulically connected to the outlet channel located in its side wall, characterized in that the outlet channel has a U-shape, constitutes a single whole with the crucible and consists of 2 -x vertical cavities, the first of which, for an upward flow of metal, is hydraulically connected with its lower part to the inner bottom of the crucible by means of a lower horizontal bridge, and its upper part is hydraulically connected by means of an upper horizontal bridge with the upper part of the second vertical cavity for a descending metal flow, the lower end which is the outlet of the crucible with the provision of automatic bottom discharge of the melt when it reaches the fluidity state, and the second vertical cavity for the downward flow of metal is structurally longer than the first vertical cavity. 2. The melting-pouring crucible according to claim 1, characterized in that the cavity of the siphon-type channel contains technological holes in the side wall of the crucible, obtained during the formation of the siphon-type channel, plugged with threaded plugs. 3. The melting and casting crucible according to claim 1, characterized in that it is made composite. 4. The melting and pouring crucible according to claim 1, characterized in that the crucible is made of a material that conducts an electric current and has a resistance greater than the resistance of the current supplying electrodes, for example, graphite.

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