RU2277133C2 - Method of casting metal into reservoirs at varying inclination and rotation - Google Patents

Abstract

FIELD: casting of refractory and chemically active metals.

SUBSTANCE: proposed method consists in preparation of melt in intermediate reservoir by molten-slag electric melting or by melting the burden by electron beam, plasma or laser beam. During rotation of inclined reservoir heavy refractory particles shift away from melt discharge. Change in rotational speed and angle of inclination of reservoir may ensure modes at which refractory particles are practically fully molten in melt and are used as master alloy. The same operations may be used for change of amount of burden batch loaded in reservoir. Melt to be poured off is additionally heated, acted on by vibration, magnetic field and ultra sound.

EFFECT: facilitated procedure of control of plant, enhanced efficiency; extended technical capabilities.

3 ck, 2 dwg

Description

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

An analogue of the proposed technical solution is a method of melting metal in an intermediate vessel with ingot casting, in which the melt is averaged well, it is cleaned of light and heavy impurities, and a defect-free crystalline structure is formed during casting. The method includes the preparation of the melt in a separate intermediate vessel with its subsequent transfusion and crystallization in the mold [1]. Melting methods in an intermediate tank with casting of ingots provide a high density of ingots, a uniform chemical composition and a fairly uniform crystalline structure. This method has found application for the manufacture of round and flat ingots of small cross section.

The closest technical solution is the method according to patent RU 2089633 C1 [2].

The aim of the invention is to increase the efficiency of use and expansion of technical capabilities.

The use of rotation of the intermediate tank allows you to increase the heating area of the melt bath. During the rotation of the intermediate tank, part of the melt rises due to the viscous properties, above the horizontal level of the main bath of the melt, providing good heat transfer due to the large heating area. In this case, a good removal of volatile and gaseous impurities from the melt occurs, intensive mixing and averaging of the composition.

Using the tilt and rotation of the intermediate tank allows the melt to be refined from heavy, volatile and insoluble impurities due to the centrifugal forces of rotation and the location of the drain hole in the center of the intermediate tank.

This goal is achieved in that the known method of casting metal in a tank with a variable inclination and rotation includes obtaining a melt in an intermediate rotating vessel and draining the melt through a central drain hole into a mold, characterized in that the melt is obtained in an inclined intermediate rotating vessel, and the metal is drained by increasing the depth of the melt pool, as well as by changing the angle of inclination and the speed of rotation of the tank. The melt being drained is heated by independent sources of heating, and the melt being crystallized is affected by vibration, magnetic field, and ultrasound.

The proposed method implements the installation depicted in figure 1. The installation includes the formed liquid bath of melt 1, a solid skull 2, the molded product (ingot; shaped casting; sheet; pipe) 3, the melt is formed by the electric arc 4, flowing down from the electrode 5. The bath is held in a rotating, spherical, inclined tank 6, neutral the atmosphere and exhaust gas evacuation is ensured by the nozzle 7, and a flexible connection 8 simplifies the design and reduces the weight of the rotary part of the installation. Water cooling 9 of the tank 6 provides heat dissipation, the solenoid 10 serves to focus or defocus the arc 4. The hinge joint 11 and the lifting-lowering device 12 provide rotation of the installation, which is mounted on the base 13. The rotation of the tank is provided by transmission 14 and the motor of rotation 16 through the seal 15. The seal 17 is used to seal the rod 22 connected to the actuator 18 of the electrode 5. The housing of the installation 20 is closed by a cover 19 on which the racks 21 of the actuator 18 are mounted. The installation may have a heating device 23, a cat An inductor, a plasma torch, an electric beam gun, and an electric resistance heater can serve as an alternative. Current is supplied to the tank 6 through sliding contacts 24. Water sealing is provided by sliding seals 25, and the casing 20 and the cover 19 are sealed by sealing 26. The force on the crystallizing melt is provided by a device 27 mounted on a mold, mold or mold 28 .

Figure 2 shows another modification of the installation, providing the implementation of the method, where the electric arc 4 is replaced by an electron beam, plasma, laser beam 4 *; the supply of raw materials is provided not due to the remelted electrode 5, but due to the lump-powder mixture 5 *; through the supply chute 18 *; the conductive rod 22 is replaced by one or more electron beam guns, plasmatrons, lasers 22 *; and the heating device may have a different arrangement 23 * with a variable axis of the heating direction; here, a plasma torch, an electron beam gun, and a laser can serve as a heater.

The method can be provided by the combined execution devices shown in FIGS. 1 and 2, where different heating sources can be used together or separately, and a combined metal feed can also be used.

When obtaining metal by melting in a dull tank or on a cold hearth, the path of a refractory poorly soluble particle in a liquid melt is limited in time. So in a solid mold, the path of a refractory particle depends on the depth of the liquid bath and the speed of rotation of the bath. The particle, spiraling at low rotation, is frozen into the skull plate closer to the center of the ingot, while at large - further from the center of the ingot. In a bath with a cold hearth, the total path of a refractory particle depends on the depth of the melt bath and its total length. In both cases, the path of a given particle cannot be infinite and sooner or later it freezes into the skull. Although in itself a refractory particle as an impurity for an alloy can be useful, only its size is harmful. If, for example, a particle of W, Mo or any refractory carbide exceeds a certain size, then stress concentrators are collected around this inclusion in the product, along which the destruction of parts occurs.

If these particles are evenly dissolved in the entire volume of the product so that they do not exceed critical sizes, then due to this, the alloy is hardened and does not have dangerous points with a stress concentration. The method according to patent RU 2089633 C1 [2], selected as a prototype, is designed to eliminate the ingress of refractory impurities into the crystallizable metal, which includes obtaining a melt in an intermediate rotating container and draining the melt through a central drain hole into a mold or mold. In contrast to it, the proposed method includes all the positive aspects of the prototype, but in contrast to it, it has a number of advantages due to the variable rotation and the angle of inclination of the container, since if it is required to more fully and efficiently prepare a certain volume of metal, then increasing the inclination from the vertical axis and rotation speed, you can get a well mixed melt. Then, if you want it to quickly drain into the mold or stamp to obtain a finer-grained structure, there is a decrease in the angle of inclination from the vertical axis and at the same time the speed of rotation. Due to a similar change in the slope and rotation, it is possible to increase the amount of loading of the batch charge into the tank, thereby simplifying the process of controlling the installation. In addition, by changing the slope and rotation, it becomes possible to change dies, molds and molds between castings without any loss of metal. At the end of melting, by translating the axis of the vessel into a vertical position and stopping rotation, it is possible to achieve a maximum decrease in the skull and a maximum discharge of the melt.

Additional heating in the drain hole area removes unnecessary accretions, and heating in the crystallization zone eliminates shrinkage shells.

An additional force effect on the crystallizing melt allows grinding grain, provides better filling of molds, improves the mechanical properties of metal.

Therefore, the proposed method can be successfully applied in production.

Information sources

1. Andreev A.L. and others. - Melting and casting of titanium alloys, - M.: Iz-in "Metallurgy". 1994 (p. 178-186).

2. The method of casting metal - RU 2089633 C1, C 22 V 9/18, 09/10/1997 g, 3 l.

Claims (3)

1. The method of casting metal, including obtaining a melt in an intermediate rotating container and draining the melt through a central drain hole into a mold, characterized in that the melt is obtained in an inclined intermediate rotating container, and the metal is drained by increasing the depth of the melt bath, as well as by changing the angle tilt and rotation speed of the tank. 2. The method according to claim 1, characterized in that the melt being drained is heated by independent sources of heating. 3. The method according to claim 1 or 2, characterized in that the crystallizable melt is affected by vibration, magnetic field and ultrasound.

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