RU2585581C2 - Method and device for electron beam melting of metal with bottom drain for moulding ingots with complex configuration - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy and can be used in electron beam remelting of metal with a floor drain for forming castings of complex configuration. Method includes forming a preform and fusing an electron beam of molten metal bath in penetrating workpiece and its bottom drain into shape upon reaching a predetermined volume of molten bath, with formation of preform is carried out in form of a washer of refiner charge on anechoic bottom ring support and fusing to form a skull to hold predetermined volume of molten bath until its bottom drain, while molten bath exposed to an alternating electromagnetic field with a solenoid. Formation of workpiece is carried out in ring support, muted cooled or bottom sheet of remelted metal washer. Silencing device comprises an annular support bottom to form a preform remelted washers, solenoid, located beneath crucible, and set top and bottom ring support torque sensors for fixing bottom of melt and drain to determine required volume of deposited molten bath.

EFFECT: invention can improve efficiency and expand technical capabilities by producing complex shapes of refractory and reactive metals.

6 cl, 2 dwg

Description

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

As an analog of the method of disk bottom discharge, skull molding with skull-consumable electrode (GRE) is adopted [1], in which melting takes place in a cooled copper crucible, from which the obtained melt is poured into a crystallizer. The remaining skull during re-melting is used as an electrode. This method does not require the preparation of special electrodes and can remelt both small-sized and large-sized charge.

The closest technical solution is the method of stamping and pulsed processing of liquid metal - “pulsed volumetric stamping” [2], in which the melt is produced in a melted billet, which then enters the stamp, where the melt is subjected to gas pressure, pressing and forging pressure through a punch , and during crystallization, mechanical and electromagnetic vibrations are imposed on the melt. To obtain a bath of melt, a previously deposited disk is laid in the installation during melting of which the melt is drained into a mold. Pressure crystallization casting methods provide a high density of castings, close to the density of deformable workpieces, and a fairly uniform structure.

The aim of the invention is to increase the efficiency of use and expand technical capabilities by obtaining products of a particularly complex shape from any metals, including refractory and chemically active ones.

This goal is achieved by the fact that the known method of electron beam bottom discharge (ELDS) is that the set volume of the molten metal bath is made in a melted billet installed in the crucible due to electron beam remelting, while the melt is drained into the mold due to melting of the bottom of the billet bath, characterized in that the billet is formed from a pre-melted mixture in this muffled crucible or by installing a sheet washer in the crucible with loading the required mass of the mixture in the washer, in p The billet is formed on the billet, where the melt bath is held, at the moment of discharge of which a predetermined volume is required, which is necessary for high-quality casting formation, the crucible is a support without a bottom where the billet is installed. Due to electromagnetic stirring with the help of a solenoid in the melt bath during the formation of the preform and before its discharge into the mold, it is possible to qualitatively average the chemical elements in the charge in the main melt, reduce the evaporation of the substance from the bath, provide more economical smelting and increase the volume of the melt being melted, melt metal during discharge and crystallization can be processed by vibration and an alternating electromagnetic field. The device of electron beam bottom discharge consists in the fact that a molten metal is deposited in a vacuum chamber by an electron beam gun in a billet formed of a charge that is held in a crucible above a mold mounted on a stand, characterized in that the crucible is made in the form of an annular support, where a washer of remelted metal can be installed, onto which a charge of the required mass is poured, or a cooled bottom is installed, onto which a charge is remelted into the workpiece, the bottom of the crucible is equipped with saline idom melt mixing, which can cover the shape and influence the melt during the crystallization of the casting, the form is mounted on sample catcher, allowing to transmit the mechanical vibrations of the melt, the electron beam gun in the lower part can be provided with individual of the exhaust pipe to further control the volatile impurities.

The proposed method implements the installation shown in figure 1, which consists of a vacuum chamber 1; electron beam gun 2, which melts a metal billet 4 with a beam 3, in which a molten bath is created 5. The billet is held on a support 6. Under the workpiece is a mold 7 mounted on a stand 8, which is equipped with a vibration device 9. A solenoid 10 and a lower one are located under the support a tracking sensor 11, a tracking sensor 12 is located on top. To create a vacuum in the melting chamber, a nozzle 13 is installed, for more reliable operation of the gun, another pump nozzle 14 can be installed below it.

Figure 1 shows the first stage of operation of the device. To create a bath of melt 5 of the required volume, a workpiece 4 is installed on the support 6, which is a circle made of a sheet. The necessary amount of charge can be loaded onto the workpiece by weight to melt the required mass of the melt bath 5 before pouring it into mold 7. The gun 2 by the beam 3 melts the charge, and a melt bath 5 is formed and a skull forms in the form of the workpiece 4, due to cooling of the melt support 6. Support 6 may be made of refractory material, such as graphite, or may be made of cooled copper.

To average the ligature in the melt bath, a solenoid 10 is installed under the support, when a current is applied to it, the melt bath will rotate. The current can be supplied in different directions, with different intervals, thereby the melt pool can rotate in different directions.

The lower tracking sensor 11 monitors the bottom of the workpiece in which the molten bath is held. According to the strength of the glow and the diameter of the light spot, a specialized program can determine the volume of the weld pool. A tracking sensor 12, mounted above the molten bath, also serves to determine the volume of the melt, tracking the beam deflection by moving and tracking the glow and diameter of the molten bath. During melting over the bath of the melt, vapors of various chemical elements take off, which are captured by the vacuum system, flying through the nozzle 13. But part of the vapor can get into the gun, violating the stability of its operation.

To eliminate this drawback, the gun can be installed not strictly along the axis of the melting chamber, but at an angle. Also, an additional nozzle 14 can be placed under the gun, which captures evaporating substances reaching the gun.

Figure 2 shows the time of the final operation of the device. After the metal bath reaches the bottom of the workpiece, it is drained in the form of a jet 15 into the mold 7. The moment of melt discharge is fixed by the lower sensor 11, relative to which the vibration device 9 is turned on, which transfers the vibration to the stand 8 and then to the mold 7. It is crushed by vibration grain casting and casting more thin-walled parts. The formation of a high-quality metal and the grinding of the casting structure can be carried out due to the electromagnetic field of the solenoid 10. By applying a pulsating or alternating current with varying periodicity to the solenoid, the emerging electromagnetic field, acting on the melt, causes multidirectional flows in it. If the exposure to the electromagnetic field does not stop during the crystallization of the casting, this also contributes to obtaining the finest-grained metal structure. For a more effective impact on the metal in the form of a solenoid 10, it is possible to make it longer in height so that it covers not only support 6, but also mold 7. Beam 3 heats the melt until it is completely merged into the mold, and the melt can also be heated in the form itself, providing directional crystallization in the casting. After crystallization of the casting 16 in the mold, the heating stops, after the casting cools to a predetermined temperature, the vacuum system is turned off and the device is depressurized to extract the mold with the casting. For re-melting on the support 6, you can again install a round sheet washer 4, on which a mixture of a certain mass is loaded. As a charge, you can use metal of any fraction, as well as waste from the previous smelting.

It is possible to make the washer 4 by depositing on the support 6, having previously drowned the support from the bottom with a cooled bottom, where the charge of the required mass is loaded. After melting the charge, a washer crystallizes on the support and the bottom, which subsequently re-melts, but already without a bottom for draining the molten bath into a mold.

It should be noted that this method of melting metals almost 100% allows you to draw waste from the previous melting into the same furnace, regardless of the source of heating. This feature allows you to drastically reduce the cost of production of metals, especially chemically active ones, and apply this design to newly mastered industries.

After manufacturing the part on the furnace, it does not need surface turning, since this surface is very smooth and clean. The technology has not only great productivity and compactness, but also the ability to produce products that are complex in configuration, including the production of plates, sheets, shaped products, etc. This technology does not require a particularly complex management system, large investments and production facilities.

This equipment can find its application in places of production and accumulation of waste, allowing to significantly reduce the cost of production, in addition, in the development of the production of casting parts by small enterprises.

LITERATURE

[one]. Andreev A.L. et al. - Titanium alloys. Melting and casting of titanium alloys. - M.: Publishing House "Metallurgy", 1994, pp. 172-178.

[2]. Volkov A.E. - RF patent No. 2194595 “Method of stamping and pulsed processing of liquid metal - Pulse volume punching”, - C2, ⁷ B22D 18/02, 03/10/2012,

Claims (6)

1. The method of electron-beam remelting of metal with a bottom discharge for forming castings of complex configuration, including the formation of a workpiece and electron beam fusion of a bath of molten metal in a melted workpiece and its bottom discharge into a mold when a predetermined volume of the molten bath is achieved, characterized in that the workpiece is formed in the form of a washer of remelted metal on the annular support plugged from below and by fusion, form a skull to hold a given volume of the molten bath until its bottom Lib, wherein the molten bath exposed to an alternating electromagnetic field with a solenoid. 2. The method according to p. 1, characterized in that for fixing the moment of bottom discharge and determining the volume of the weld pool of the melt using the upper and lower sensors. 3. The method according to p. 1, characterized in that the formation of the workpiece is carried out in an annular support, damped by a cooled bottom or sheet washer of remelted metal, and during the discharge of the molten metal and crystallization of the casting, they vibrate and are exposed to an alternating electromagnetic field. 4. A device for electron-beam remelting of metal with a bottom discharge for forming castings of complex configuration, containing a vacuum chamber with an electron-beam gun, which provides fusion of a bath of molten metal in the billet and the fusion of the bottom of the said billet, and a mold for crystallization of castings mounted on a stand with a vibration device characterized in that it comprises an annular support plugged from below for forming a remelted workpiece in the form of a washer, a solenoid located under the crucible, and installed e top and bottom ring support aid for fixing points in the bottom discharge of the melt and determining the volume of the deposited molten bath. 5. The device according to claim 4, characterized in that the solenoid is configured to mix the molten metal bath and to influence the molten metal during crystallization of the casting in the mold, and the plug of the annular support is a cooled bottom. 6. The device according to p. 4, characterized in that it is equipped with a pumping nozzle located under the electron beam gun for trapping volatile impurities, and the cap of the annular support is made in the form of a sheet washer from remelted material.

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