SU753527A1 - Method of producing ingots - Google Patents

Description

The invention relates to metallurgy and can be used in the preparation of ingots by layer-by-layer metal buildup. There is a known method for producing blanks, which uses the method of layer-by-layer crusting. The disadvantage of this method is the occurrence of boundaries between frostbone metal layers, in which various kinds of contaminants are collected, coming from the poured metal in the form of liquidation elements: sulfur, phosphorus and others, as well as contaminants falling from the pressure tool. . Also known is a method of casting metals, which consists in the fact that before freezing the next layer on the surface of the ingot a stream of liquid metal is fed and the metal layer of the previously frozen frost 2 melts. The disadvantage of this method is that it is difficult to maintain the working surface of the tool / free from skardovin, which makes it difficult to form a good quality ingot. The purpose of the invention is to exclude segregation and to produce ingots with a homogeneous fine-grained metal structure throughout the cross section and lacking a liquoritel, due to the fact that the layer-by-layer buildup of the ingot is made from crushed and cooled to a solid-liquid state of metal cleaners, while after building up each layer its surface is blown off. neutral gas until solidified. The method is explained in the drawing. From the tank 1, the liquid metal is supplied through the metal conduit 2 by ejecting it with an inert gas fed through the tube 3. In the ejector 4, made, for example, of refractory material, the metal is crushed into small droplets of a given fraction and ejected with a torch 5 also with a given opening angle in particular, depending on the required size of the sprayed area. The torch 5 is closed in the cooled jacket 6, which removes heat from the torch radiation. The torch 5, consisting of small droplets of metal, reaches at the beginning of the surface of the seed 7, and then the ingot 8 as it expands and is drawn into a cooled crystallization e 9. Before the torch enters the crystallizer it is formed with a collimator (not shown) after which the torch of the point is recorded in the profile of the ingot. By the time the end of the ingot 8 is reached, the droplets are cooled by an inert gas which, escaping through the hole in the casing G, absorbs heat, and also due to radiation heat, is absorbed by the coolant circulating in the casing . Both of these heat removal paths are regulated to achieve the necessary heat removal from the metal droplets. In these cases, the heat of its overheating can be removed from the metal, as well as a part or completely hidden heat of crystallization. Thus, the particles of the metal, dispersed by gas to the required speed, reaching a supersonic one, are welded into a dense, monolith, and the subsequent heat transfer from it flows in the crystallizer. The ingot is formed according to the proposed method under the conditions of complete: - suppression of segregation, processes with a uniformly distributed fine-grained structure of the cast metal.

The spreading angle of the spray gas jet is regulated within wide limits (from 45 to 5 °). Due to the high speed of flight, the length of the torch can reach three meters, while maintaining sufficient kinetic energy. These two circumstances ensure the fabrication of metal parts by spraying a complex configuration with an absolutely uniform uniform cast structure without shrink holes and without metal residues on the sprue.

Argon and nitrogen are used as neutral gas. In some cases, ordinary air is used, for example, in the preparation of individual castings from cast iron.

The buildup is carried out on the lower surfaces, as well as on the upper (ceiling) and side surfaces of the ingots.

When producing ingots of some metals and alloys, for example, highly heat-conducting, the torch is cooled to a limited extent or even heated, using, in particular, reflective ones. surface heat. This makes it possible to equalize the temperature over the cross section of the flame, while its outer layers turn out to be quite hot and, at the entrance to the mold, provide a high quality ingot surface.

The prb5 crude method for producing ingots is implemented as follows.

Upon receipt of the ingot of carbon steel having a liquidus temperature of 1520 ° C, and solidus, the metal is superheated to a temperature above the liquidus and is fed from the tank

1 through a metal conduit 2 with inert gas to the ejector 4. Neutral gas (nitrogen or argon) is fed at a speed that reaches and exceeds sound speed (hundreds of meters per second). In the ejector, the metal jet is regulated -. This creates torch accuracy with well-defined boundaries, as well as regulates the size of the sprayed metal particles obtained. The form is set at a certain distance from the ejector, depending on the temperature state in which the formation of the surface layers on the end face of the ingot takes place. The limits of this distance are determined from the following data.

It is known that when spraying a liquid metal, a particle size of 0.05 m in diameter is obtained.

There are reports of thinner powders ranging in size from 0.1 to 0.001 mm. At the same time, their cooling rate reaches 10 - 10®grad / s

Assuming an average velocity of the sputtered particles of 300 m / s and an average particle cooling rate of 10 degrees / s, the reduction in the temperature of the particle plume is determined.

To form the surface layers of the ingot face at temperature in the solid-liquid state, the bottom of the mold must be installed within 1 meter of the ejector. In this case, the overheating of the steel and a part of the latent heat of crystallization are selected.

In accordance with the above calculation, even at a distance of 1 m, the crystallization heat is removed almost completely from the ejector (since cooling at 30 ° C is almost equivalent to removing the latent heat of steel crystallization).

Thus, within 1 m of the ejector, it is possible to freeze metal layers with different degrees of selection of the latent heat of crystallization. The exact distance is established empirically. To preserve the identity of the ingot formation conditions, as the thickness of the ingot layers increases, the shape is lowered so that the ingot face is at a given constant distance:

Claims (2)

In order to achieve a layer-by-layer build-up of an ingot from metal particles crushed and cooled to a solid-liquid state, the mold is moved in a horizontal direction. For this, a spray plume delivers to the bottom of the mold to one of its edges. At the same time, the torch area takes from 1/2 to 1/10 of the cross-sectional area of the mold (mold). Moreover, from the moment the spray torch is supplied, the form moves horizontally until the edge of the torch reaches the opposite wall of the form ,. After this, the form changes its direction, and thus the form moves cyclically at a certain speed, and successively the movement of the metal plume is followed by a flame of neutral gas directed onto the surface of the newly applied layer in order to cool it. At each cycle, a layer of solid metal is imparted at the end of the ingot. In this connection, the mold is lowered in accordance with the rate of growth of metal layers at the end of the ingot and, after cooling, the ingot is removed from the mold of the mold. A modification of the method is the creation of layers of particles with a completely removed latent heat of crystallization and having a temperature up to the values used during conventional plastic deformation of the stage (12001250 ° C). In this case, the distance of the cooling zone of the torch increases and is within 1 -3 meters from the ejector. This zone is established empirically. Calculations show that at temperatures of solid steel particles from the highest to 1200-1250 ° C, the pressure generated by the flying particles is sufficient for plastic deformation and to obtain a dense preform or ingot from freshly solidified particles. This way of creating an ingot completely eliminates any undesirable redistribution of segregation beyond the limits of a single particle. A modification of the method of layer-by-layer build-up of an ingot is also in that the metal torch is moved along the end of the ingot, and the jet is followed by a cooled jet of neutral gas. A modification of the method is also the fact that in order to obtain a bimetallic casting, it is built up with two torches, spraying metal of different compositions in turn. When creating sufficiently powerful metal fvelos by the proposed method, large metal buildings were made complex. Pipe blanks are especially well worn in this way. At the same time, its extension is carried out from the end by one or several shafts, for example, when rotating the gauges around its axis with the blowing of areas with a torch of neutral gas, the Proposed method is special; useful in the manufacture of ingots and castings of hard metals, tool steels of tungsten, molybdenum, their alloys, light metals of their alloys, iron and his: alloys. The method allows to obtain finished parts with minimal machining or with its complete exclusion. Claims The method of producing ingots, including its layer-by-layer extension, characterized in that, in order to eliminate likvadiya and obtain a homogeneous fine-grained structure over the entire section of the ingot, the layer-by-layer build-up of the ingot is made from crushed and cooled to solid state mettshla, while after building each layer its surface is blown with neutral gas until it is completely hardened, and information sources, taken into account during the examination 1.Certificate of certificate; USSR No. 231070, cl. In 22 D 11/00, 1964. 2. USSR author's certificate number 475115, cl. In 22 D 11/00, 1971 (prototype).