RU2301841C2 - Method of forming metal ingot - Google Patents

Abstract

FIELD: special-purpose electrometallurgy; forming titanium ingots.

SUBSTANCE: melt is additionally heated in ingot mold and crust is simultaneously broken; melt is compacted for forcing out the gas component from pores by transfer of thermal and mechanical energy to melt through chemically neutral conducting rod and is mixed by electromagnetic action at passing the electric current through melt, thus creating the axial and radial magnetic fields in volume of melt. Rod is continuously kept at electromechanical contact with melt.

EFFECT: improved quality of ingot.

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Description

The invention relates to electric arc metallurgy and can be used to improve the quality of titanium ingots and alloys.

For the production of titanium and alloys based on it on an industrial scale, electric arc vacuum furnaces with a consumable electrode are used [1, 2]. Currently, two types of furnaces are used in industrial operation: a vacuum arc furnace (VDP), in which the consumable electrode is remelted directly in the mold (crystallizer), and a vacuum arc skull furnace (VDGP), where the consumable electrode is remelted (return skull) together with the skull is carried out in the crucible, and the melt from the crucible merges into an independent mold, in which an ingot is formed.

Unlike the VDP, the skull furnace does not require a powerful press for the manufacture of the consumable electrode, since the new electrode, along with the ingot, is obtained in each melting cycle, and waste is loaded into the crucible of the furnace, the dimensions of which can be commensurate with the internal dimensions of the crucible.

The formation of a large melt pool contributes to the completeness of the flow of physical and chemical processes in it, improving the chemical interaction of various components and averaging the chemical composition.

A significant drawback of the existing method for producing an ingot in VDGP is that the melt is poured into an independent water-cooled mold or into a mold with massive walls, where the ingot is formed without any external influences. With this method of producing the ingot, significant porosity occurs along the entire length of the ingot. Particularly, porosity increases in the area of shrinkage shell formation. One of the reasons for the formation of porosity is crystallization "from above", in which a crust forms.

The purpose of the invention is to improve the quality of the ingot is achieved by additionally heating the melt in the mold, at the same time destroying the crust, compacting the melt, displacing the gas component of the pore by transferring heat and mechanical energy through the chemically neutral electrically conductive rod to the melt and mixing it with electromagnetic action when passing electric current through the melt with the creation of an axial and radial magnetic field in the volume of the melt, while electromechanical contact is constantly maintained t rod with a melt.

The proposed method explains the diagram shown in the drawing.

The molten metal from the crucible (not shown) is discharged into the mold 1 through a trough 8. The water-cooled mold is made of ferromagnetic steel with a wall thickness of about 300 mm. The water-cooled mold is made of non-magnetic material. Ingot 2 is formed from the melt by intensive heat exchange between the melt and the mold wall. As a result of this ingot formation method, pores 3 and crust 4 are formed during crystallization from above, which prevents the gas component of the pores from escaping. With the axial part of the ingot and in the area of formation of the shrink shell, friability of the metal occurs, and as a result it becomes unsuitable for the manufacture of products. In order to prepare a consumable electrode from such an ingot for re-remelting in the VDP, it is necessary to cut the lower and head parts of the ingot into waste. In this case, up to 25% of the ingot metal can go.

To reduce the porosity of the ingot, the rod 9 is lowered below the melt mirror, additionally heated by a heater 10 with a power source 11 to a certain temperature that prevents the formation of crust 4. At the same time, the rod is subjected to mechanical vibrations by a device consisting of a magnetostrictive insert 16 of the rod, a solenoid 14, fed by an alternating current source 15 Mechanical vibrations from the insert are transmitted through the heat-insulating adapter 12 to the rod 9 and then to the melt 2. Mechanical vibrations of the rod at the same time ushayut crust densified melt and displace the gas composition pores. The current from the current source 7 is passed through the melt, and an axial and radial magnetic field is created by the solenoid 5 connected to the current source 6. As a result of electromagnetic interaction, the melt is mixed.

With the formation of a shrinkable shell, the mechanical, thermal, and electrical contact of the rod 9 with the melt 2 may be disturbed. The constant contact is stabilized by the device for the vertical movement of the rod 17 controlled by the electronic unit 18.

When the contact breaks on the resistance 13, the voltage rises to the electronic unit, which instructs the device 17 to move the rod down until a reliable contact is formed.

The proposed method is quite easily implemented in practice, does not require large costs for the manufacture of a device by this method, and its efficiency is high.

Information sources

1. A.Sh. Fridman, M. Kostantsi, F. Orella. Skull melting plant for the production of titanium ingots. Scientific and technical journal "Titan", 2002, No. 1 (11), pp. 7-10.

2. L.D. Volokhonsky. Vacuum arc furnaces. M., Energy Publishing House, 1985, 232 pp. (prototype).

Claims (1)

The method of forming a metal ingot, including an arc remelting of the skull in a crucible, draining the melt into a mold, characterized in that it further heats the melt in the mold, simultaneously destroys the crust, compacts the melt, displaces the gas component of the pore by transferring thermal and mechanical energy through the chemically neutral electrically conductive rod to the melt and mixed by electromagnetic action while passing an electric current through the melt with the creation of an axial and radial magnetic field in the volume of the Av, while constantly maintained electromechanical contact rod with the melt.