RU2660784C2 - Device for vacuum melting of refractory and reactive metals - Google Patents

Abstract

FIELD: electrometallurgy.

SUBSTANCE: invention relates to special electrometallurgy and can be used for vacuum melting of refractory and reactive metals. In the method, the device comprises a melting chamber, a cooled crucible for melting the metallic charge and cleaning the resulting melt from heavy and light impurities, a crucible tilt mechanism, a electron-beam guns located at different angles with respect to the axis of the melting chamber casing, and a mold for forming an ingot. Said melting chamber is a horizontally arranged pipe with a vacuum branch pipe and a flange, closing it laterally through the sealing vacuum rubber, the crucible is in the form of a trough with drains for the purified melt into said mold, the crucible and the crystallizer are located in the melting chamber and are made with the possibility of alternating inclinations along or across the plane of the bath for stirring the melt. To form a plate or sheet, the mold is flat, and to form half-electrodes, it is semicircular. Also, the crystallizer can be made round with holes, located opposite the drains of the trough.

EFFECT: invention allows to expand technological possibilities due to saving energy costs, reducing the production cycle, as well as reducing the size of the equipment.

4 cl, 2 dwg

Description

The present invention relates to the field of foundry and can be used for casting any metals, including refractory and chemically active.

As an analogue of the invention, a method of electron beam remelting with a cold hearth [1] is adopted. In this method, the source material in the form of a charge, sponge, powder or granules moves with a certain speed from the charge hopper into the cooled crystallizer. In the mold, the metal melts, and the formed liquid metal drops or (with sufficient electron beam power) flows continuously into a sliding cooled mold, forming an ingot of the required size. This method of remelting can also be called electron beam remelting with an intermediate capacity. By purpose and implementation scheme, it is completely identical to plasma remelting widely used in industry. However, in contrast to plasma remelting, a deeper purification of metal from gas impurities is possible here, when the melt in vacuum is held for a sufficiently long time required for metal refining.

The closest technical solution adopted as a prototype is a plasma or electron beam method of melting in a flat crystallizer [2]. Melting in a flat crystallizer was developed by the American company "Frankel", where the furnace operates due to the fact that the charge fills the mold. The mold moves on wheels inside the chamber under the plasma torch, which can rotate and move up and down. After fusion of a certain portion of the charge, a second one is added until the ingot reaches the desired thickness. The resulting ingot is subsequently used for vacuum-arc remelting. Furnaces of this design with electron beam heating are produced by the Russian company Giredmet. The main advantage of the melting method in a flat crystallizer is the possibility of producing flat ingots, the main disadvantage is the complexity of the equipment, which uses a moving mold, a small penetration depth of the charge and a small possibility of averaging the chemical composition.

The task of the invention is to increase the efficiency of use and expand technical capabilities by reducing energy consumption, shortening the production cycle, increasing the mass of metal during melting, and reducing the dimensions of the equipment.

This object is achieved in that a device for melting in a swinging crucible containing a melting chamber, a crucible with a charge, an electron beam or plasma gun, an intermediate tank, a crystallizer, is characterized in that the crucible combines the functions of a container and an intermediate tank, representing a long swivel chute with one or more drain socks, placed above the mold inside the melting chamber, which is made in the form of a pipe, for intensive mixing of the melt, the crucible and the mold Gut be provided with the tilting mechanism in the space and for better averaging crucible chemical homogeneity can be provided with several drain toes instead of the mold can be fitted shape, which are placed under the drain for pouring sock.

The proposed method is carried out using the installation shown in figure 1. The installation contains an electron beam gun 1, which can be located at different angles with respect to the axis of the casing of the melting chamber 2, which is closed laterally by a flange 3 through sealing vacuum rubber. A copper cooled crucible 4 and a crystallizer 5 are placed in the melting chamber. A charge 6 of any kind is loaded into the crucible 4. After installing the crucible and the mold in the melting chamber, a vacuum is created through the nozzle 7. When the required vacuum depth is reached, the mixture is melted by the electron beam 8. The crucible for draining the melt is made inclined. The charge 6 will be melted by the beam due to its movement on the metal surface until a liquid bath 10 is formed on a certain surface area of the crucible. After a metal bath of a certain depth has formed in the crucible, the melt is drained into the crystallizer through the nose 9 due to the rotation of the crucible. There may be several socks 9 on the crucible.

During the formation of the molten metal bath 10, the crucible can incline alternately along or across the plane of the bath to mix the melt, and after the mixed melt can merge into the mold due to the inclination of the crucible. The electron guns 1 must be mounted in such a way on the housing 2 so that they can most effectively beam the surface of the charge being loaded in the crucible and the surface of the metal being poured into the mold.

On figa shows the installation, where as the mold 5 is a flat mold, which allows you to form plates or sheets.

On figb shows the installation, where the mold 5 acts as a semicircular mold, which allows the formation of semi-electrodes, from which it is subsequently possible to manufacture electrodes for VDP furnaces. This mold can be oscillating, this allows the melt to be further mixed inside the mold. The production of semi-electrodes, a quarter of the electrodes or individual sectors of the electrodes is especially relevant for the remelting of the charge, where you can determine its exact chemical composition. After smelting, for example, a semi-electrode, the exact chemical composition is determined, and if it needs to be adjusted, this charge or pure metal can be alloyed with the necessary chemical elements when loaded and fused into the second semi-electrode. Further, an electrode is formed from semi-electrodes by welding or other means for subsequent remelting, for example, vacuum-arc or electron-beam, where a given chemical composition of the final metal is created during the remelting process. In order to more efficiently average the chemical composition, it is possible to create an electrode from semi-electrodes, folding them with different ends. For example, if the end of the first half-electrode was formed on the left side of the crucible, then it is connected to the end of the half-electrode formed on the right side of the crucible. In semi-electrodes, metal storage is possible, where a code with full information is applied to the ingot. After receiving an order for the necessary alloy from a semi-electrode, it is possible to compose an electrode of the required chemical composition.

Figure 2 shows the installation with a round mold 5, in which several holes are made opposite the drain socks of the crucible 4, which allows the production of finished electrodes 11. For the subsequent vacuum arc melting, this mold can be made on the same frame with the crucible, therefore, due to one inclined mechanism in the mold and crucible metal can be mixed.

A feature of the proposed device is that it can produce an ingot at the lowest cost from various alloys of round, square or rectangular shape with one or more guns (or plasmatrons), without the use of filling, feeding and exhaust devices. Due to the compact device, which is an ordinary pipe, the furnace with a swinging crucible is very compact and does not require digging pits. Therefore, the cost, construction time and payback of the furnace will be small.

The equipment is compact due to the fact that the crucible simultaneously serves as a storage tank for the charge, an intermediate tank in which heavy and light impurities are cleaned, and a drain device. That is, the crucible combines the functions of a hopper, where the charge is loaded from the intermediate tank, where the metal and crucible are cleaned, due to the rotation of which the metal melt is drained into the mold. The charge loading is provided in the crucible without any special preparation. Loading the mixture is possible without mechanical mixing and special laying.

The metal merges from the crucible, being premixed due to its periodic tilts in the plane. Mixing is enhanced by the tilts of the mold.

The place of discharge of the molten metal from the crucible can be located above the mold in its center, as well as in the center and near the edges of the mold. This allows, due to the inclination of the crucible, to alternately drain the melt from it, first from one edge, then in the center and then from the other edge. So, for example, it is possible to melt the melt in one part of the crucible, and drain it in another part. The crucible can have two drain socks, which allows, due to the inclination of the crucible, to drain into the mold first, for example, on the right side, and then on the left.

There may be one toe on the crucible, but due to the inclination of the crucible and the crystallizer, the melt will mix intensively. Instead of a crystallizer, it is possible to use separate forms, which are filled in one tilt of the crucible. After filling one form, a new form is substituted under the drain sock, which is filled after the fusion of a new portion of the melt and the repeated inclination of the crucible.

To increase the productivity of the furnace, it is possible to supply it with a second crucible and a crystallizer, which are outside during melting of the furnace, while the second crucible is loaded with a new charge. As soon as the melting process is completed, the crucible and mold are removed from the furnace for cleaning and removing ingots, and a new crucible and mold are installed in their place.

The design of the furnace device for implementing the method has a minimum volume of the melting chamber and is a horizontal pipe located on the workshop area without a foundation pit. The internal configuration of the cavity of this chamber occupies space only for the placement of a horizontal crucible and a crystallizer. This feature allows you to reduce the cost of installation design, reduce the cost of the vacuum system and reduce the time for pumping air from the melting chamber. These advantages allow us to consider the present invention useful for industrial use.

LITERATURE

1. A.A. Andreev. Melting and casting of titanium alloys. - M .: Publishing house "Metallurgy", 1994, p.182-184.

2. A.A. Andreev. Melting and casting of titanium alloys. - M.: Publishing House "Metallurgy", 1994, p. 179-180.

Claims (4)

1. Device for vacuum melting of refractory and chemically active metals, containing a melting chamber, a cooled crucible for melting a metal charge and removing heavy and light impurities of the resulting melt, a crucible tilt mechanism, electron beam guns located at different angles with respect to the axis the case of the melting chamber, and the mold for forming the ingot, characterized in that the melting chamber is a horizontally arranged pipe with a vacuum pipe and a flange that closes it on the side cutting vacuum rubber, wherein the crucible is made in the form of a chute with drains for the purified melt into the said mold, the crucible and the crystallizer being placed in the melting chamber and made with alternating inclination along or across the plane of the bath to mix the melt. 2. The device according to claim 1, characterized in that for the formation of a plate or sheet, the mold is made flat. 3. The device according to claim 1, characterized in that for the formation of semi-electrodes, the mold is made semicircular. 4. The device according to p. 1, characterized in that the mold is made round with holes located opposite the drains of the said trough.

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