US 3749149 A
Description (OCR text may contain errors)
United States Patent [1 1 Paton et al. I
METHOD AND AN ELECTRON-BEAM FURNACE FOR INGOT PRODUCTION Filed: May 3, 1971 Appl. No.: 139,464
Foreign Application Priority Data June 15, 1970 U.S.S.R 439143 June 15, 1970 U.S.S.R 1439144 US. Cl 164/50, 118/495, 141/283,
[4 1 July 31,1973
 Int. Cl 822d 27/02  Field of Search 164/50, 250, 84, 164/85, 87, 88, 136, 276, 335; 219/60 A, 60
Primary Examiner.l. Spencer Overholser Assistant ExaminerJohn E. Roethel Attorney-l-Iolman & Stern [5 7 ABSTRACT The method of the present invention provides for melting a metal charge in an electron-beam furnace over a tundish and for solidifying molten metal in a mould the capacity of which is increased in a horizontal direction as it is filled with hot metal. The capacity of the mould is increased by moving its trough-shaped casing in a horizontal plane relative to its internal partition. In order to produce multi-layer ingots, the internal partition is lifted for a distance equal to the thickness of the previous solidified layer of the ingot. Electronbeam surface for realizing this method includes a vac uum chamber, a charger, and electron guns.
4 Claims, 1 Drawing Figure METHOD AND AN ELECTRON-BEAM FURNACE FOR INGOT PRODQCTION The present invention relates to methods for ingot production and to electron-beam furnaces for the realization of these methods.
In the prior art, there is known a method for ingot production by melting a metal charge in an electronbeam furnace over a constant-capacity tundish and a variable-capacity mould.
Also known in the prior art is an electron-beam furnace for the realization of this method, comprising a vertical mould whose capacity can be varied by moving or lowering a dummy-bar relative to the stationary mould. In these electron-beam furnaces, the metal charge is melted over either the mould r or a tundish from which the molten metal is transferred into the mould. n solidification, one obtains round or square ingots which have to be forged into flat slabs before they can be made into sheets. in electron-beam furnaces using these prior-art moulds, it is impossible to obtain ingots in the form of flat slabs and to avoid the expensive operation of forging or rolling the'ingots into flat slabs. Nor can these electron-beam furnaces produce multi-layer cast slabs. Furthermore, in the priorart methods, ingots are pulled out of the mould, and this results in tears and cracks on the surface of the ingot, impairing its quality.
It is an object of the present invention to avoid the above-mentioned disadvantages.
The present invention is directed to providing a method for ingot production and an electron-beam furnace for the realization of this method which will cut down the cost of slab production for sheets by producing cast slabs for sheets directly in the electron-beam furnace. The invention also aims to improve the surface quality of the resultant flat slabs, including multi-layer slabs.
With these objects in view, the present invention relates to a method for ingot production by melting a metal charge in an electron-beam furnace having a constant-capacity tundish and a variable-capacity mould, in which, according to the invention, the capacity of the mould is increased in a horizontal direction as it is filled with hot metal. This method cuts down the cost of slab production for sheets by eliminating the forging or rolling of ingots into flat slabs prior to sheet production.
It is preferable to increase the capacity of the mould by moving its trough-shaped casing in a horizontal plane relative to its internal partition. This improves the quality of the ingots by eliminating the formation of cracks and tears in the skin of the ingot.
To form the next layer of the ingot, the internal partition can be lifted for a distance equal to the thickness of the previous solidified layer of the ingot, and the mould can be brought back to its starting capacity, after which the feed of hot metal can be resumed. Thus it is possible to produce multi-layer slabs.
To realize the method, an electron-beam furnace has been designed, including a vacuum chamber fitted with a charger and enclosing electron guns, at water-cooled tundish, and a water-cooled mould, in which, according to the invention, the mouldis made in the form of a trough-shaped receiver mounted so that it can be moved in a horizontal plane relative to an internal partition fastened inside the vacuum chamber.
This type of furnace cuts down the cost of production of slabs for sheets, since cast slabs for sheets are produced directly in the furnace, so that the foregoing or rolling of ingots prior to sheet production can be dispensed with. This furnace also improves the quality of the ingot surface.
It is preferable to fasten the internal partition of the trough-shaped receiver in the vacuum chamber so that it can be lifted for a distance equal to the depth of the trough-shaped receiver thus making it possible to produce multi-layer cast slabs.
The invention will be more fully understood from the following description of a preferred embodiment of an electron-beam furnace for the realization of the method disclosed herein, when read in connection with the accompanying drawing which shows a perspective view in cross-section of an electron-beam furnace.
Referring to the drawing, there is shown an electronbeam furnace which has a vacuum chamber 1 fitted with a device not shown in the drawing to charge the metal 2 to be melted and enclosing electron guns 3, 4 and 5. Within the melting zone of the charge 2 there is a tundish 6 made fast to the vacuum chamber 1 of the electron-beam furnace. The bottom of the vacuum chamber 1 has a rail track 7 on which is riding a trolley 8 coupled by a tie-bar to a reciprocating mechanism-- not shown in the drawing-which actuates the trolley in a horizontal plane. The reciprocating mechanism can have a mechanical or a hydraulic drive. The trolley 8 carries a trough-shaped receiver 10 with a transverse internal partition 11 coupled by hollow tie-bars 12 to a lifting mechanism-not shown in the drawing-which lifts the partition. The lifting mechanism can have a mechanical or a hydraulic drive. Cooling water is fed into the tundish 6 by means of hollow tie-bars 13, into the trough-shaped receiver 10 by means of hollow tiebars 14, and to the internal partition 1 l by means of the hollow tie-bars 12.
The electron-beam furnace for realizing the method according to the invention operates as follows:
The charger-not shown in the drawing-feeds the source material 2 into the melting zone where it melts under the action of the electron gun 3. The molten metal 2 trickles into the tundish 6 where it is further heated by the electron gun 4 and from which it overflows into the horizontal trough-shaped receiver 10.
In the starting position of the trough-shaped receiver 10, its minimum initial capacity is limited by the internal partition 11 and the end wall 15 of the receiver 10, brought close to it.
The metal collected in the receiver 10 is heated by the electron gun 5. As the initial capacity of the receiver 10 is filled with hot metal, the trolley 8 carrying the receiver 10 is moved to the right, which, in the embodiment in question, is carried out by a reciprocating mechanism not shown in the drawing. The reciprocating mechanism may have a mechanical or a hydraulic drive. As a result of this movement, the distance between the internal partition 11 and the end wall is of the receiver 10 is increased, and molten metal fills the increased capacity of the receiver 10. On leaving the zone illuminated by the electron gun 5, the metal cools and begins to solidify away from the end wall 15 towards the partition 1 1 of the receiver 10. This produces the first layer 16 of an ingot. After the first layer 16 of the ingot has been formed, the electron guns 3, 4, and 5 are turned off, the internal partition is lifted for a distance equal to the thickness of the first solidified layer 16 of the ingot by a lifting mechanism-not shown in the drawing, and the receiver mounted on the trolley 8 in this embodiment is brought back to its starting position by the reciprocating mechanism-not shown in the drawing-so that the wall is brought close to the partition 11. Then the electron guns 3, 4, and 5 are turned on again, and a second layer 17 of the ingot begins to be formed. This second layer may be made of the same or any other metal, as desired.
The process described herein produces ingots in the form of flat slabs which can readily be rolled into sheets.
1. A method for the production of slab-like ingots, comprising the steps of melting metal in an electronbeam furnace over a tundish; transferring the molten metal from said tundish into a mold made in the form of a trough-like tray whose length is divided by a vertical partition extending transverse said tray; moving said mold horizontally lengthwise relative to said partition to increase the volume of the space to be filled with liquid metal; and pouring molten metal into said mold to form the slab-like ingot.
2. The method as claimed in claim 1, comprising the further steps of vertically moving said partition to a height equal to the thickness of a preceding slab-like ingot; returning said mold to its initial position; and again pouring molten metal therein to form another layer of the slab-like ingot.
3. An electron-beam furnace for the production of slab-like ingots comprising a vacuum chamber; charging means to supply said chamber with metal to be remelted; electron-beam guns to melt said metal within said electron-beam furnace; a water-cooled tundish for molten metal located within said vacuum chamber; a mold in the form of a trough-like tray adapted to move lengthwise in a horizontal direction; a vertical partition within said chamber adapted to enter the mold space of said mold and transversely divide it; and means for moving said mold lengthwise in a horizontal plane relative to said partition so as to increase the volume of the molding space.
4. The electron-beam furnace as claimed in claim 3, wherein said partition is adapted to move vertically relative to said mold, there being power means to accomplish this vertical movement.
i k III l