RU2228962C2 - Vacuum melting furnace with cold hearth - Google Patents

Abstract

FIELD: special-purposed electrometallurgy; production of ingots and slabs of high-reaction metals of commercial purity. SUBSTANCE: proposed furnace has working chamber, independent heating sources, cold hearth on which water-cooled melting and refining crucibles are mounted, three or more independent burden loading units located concentrically relative to melting crucible made in form of polyhedron. Melting crucible is so positioned that one of its walls is located under each loading unit perpendicularly relative to its axis. EFFECT: enhanced efficiency; continuity of melting process. 1 dwg

Description

The invention relates to the field of special electrometallurgy and may find application for the production of ingots and slabs of highly reactive metals of commercial purity.

A known design of an electronic melting furnace patented in the USA in 1965 by the company Temescal Metallurgical Corp. (Smelyansky M.Ya. Electronic furnaces. - M .: Energy, 1971, p. 34). The design of the furnace includes a working chamber in which independent heat sources are installed, a cold under and a loading device.

The disadvantages of the furnace are: low productivity of the furnace (when reloading the remelted billet the furnace stops), the possibility of melting only a monolithic billet, the difficulty of introducing alloys into the melt.

A known method of electron beam remelting of titanium sponge and installation for its implementation (RF patent No. 94037492, publ., 07.20.97), containing a consumable titanium container, feed device, electron guns with deflecting systems, an intermediate tank and a mold.

The disadvantages of the installation are the necessity of manufacturing a consumable container, filling it with a charge, loading it into the furnace and feeding it into the remelting zone, and stopping the furnace during reboot.

Known design of the furnace EMO-1200 (Smelyansky M.Ya. Electronic furnaces. - M .: Energia, 1971, p. 42-43), consisting of a working chamber, two conveyors for feeding the melting rods, located on one axis and directed towards each other friend, independent heating sources and a copper water-cooled crystallizer - a prototype.

The design disadvantages are large overall weight parameters due to the location of the feed conveyors, the inability to use bulk materials as a charge, the need to stop the furnace during reboot, which significantly reduces the useful life of the furnace.

The problem to which this invention is directed is to increase furnace productivity and optimize the smelting process.

The technical result of the invention is the creation of a vacuum melting furnace with a cold hearth, in which the operation of loading into the furnace of the mixture and alloying elements with their subsequent supply to the working area are carried out independently from each other and without stopping the melting process.

The technical result is achieved in that in a cold hearth vacuum melting furnace containing a working chamber, charge devices for the charge, independent heat sources, a cold hearth on which water-cooled melting and refining crucibles and a crystallizer are installed, the furnace has three or more independent loading devices, placed concentrically with respect to the melting crucible, made in the form of a polyhedron, and the melting crucible is installed in such a way that under each loading device perpend angles to its axis disposed to one of its walls.

The invention is illustrated in the drawing, which shows a top view of the furnace.

The melting furnace contains a melting crucible 1, refining crucibles 2 and 3, a mold 4, a working casing 5, loading devices 6, consisting of a feeding device 7 and a lock chamber 8.

The operation of the furnace is as follows.

In the working casing 5 creates a vacuum. The mixture is loaded into the lock chamber 8 of the loading devices 6 and then using the feeding devices 7 is fed to the melting crucible 1.

As the crucible is filled, the liquid metal through the overflow threshold enters the refining crucibles 2 and 3, and then into the mold 5, where it is formed into an ingot. Melting and maintaining the temperature in the furnace are carried out using independent heating devices. The mixture during melting is fed to the first boot device. After the charge is completely consumed in this loading device, the charge is supplied from the second device, and the first device is loaded through the lock chamber with the charge. It is also possible the simultaneous filing of the ligature on the third boot device in the melting zone, as well as the operation of all devices simultaneously. The use of three independently working loading devices significantly increases the functionality of the furnace. It becomes possible to continuously introduce into the melting zone a heterogeneous mixture and ligature in the optimal ratio both in chemical composition and in geometric dimensions. The geometric shape of the crucible is selected in the form of a polyhedron based on the following conditions:

1. When loading, ensure that the charge is placed directly in the zone of operation of an independent heating source (for example, an electron beam of an electron beam installation). The movement of the charge from the zone of direct influence of the heating source is limited by the wall of the crucible, perpendicular to the axis of the loading device.

2. The rational placement of boot devices, guaranteeing their independent and reliable operation, as well as ease of operation and repair.

Example. A cold hearth plasma arc furnace was manufactured for smelting titanium alloys with a capacity of 450 sq. A and a capacity of 2500 tons per year. The furnace is equipped with three independent loading devices having lock chambers and placed concentrically above an octagonal melting crucible. The axis of each loading device is perpendicular to one side of the crucible. The axes of the devices themselves are placed at an angle of 45 ° relative to each other. Loading devices can be in three operating modes: loading, feeding of melting material or standby. Each device is capable of loading any type of charge: bulk, pressed or cast. By regulating the operation of these mechanisms, it is possible to feed a mixture into the melting zone in various combinations in accordance with the requirements of the technology in terms of chemical composition, size of fractions and volume.

Claims (1)

A cold hearth vacuum melting furnace containing a working chamber, charge loading devices, independent heating sources, a cold hearth on which water-cooled melting and refining crucibles and a crystallizer are installed, characterized in that the furnace has three or more independent loading devices placed concentrically in relative to the melting crucible, made in the form of a polyhedron, and the melting crucible is installed so that under each loading device perpendicular to its axis is located the wife of one of its walls.