US3894573A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Installation and method for plasma arc remelting of metal
Assignee: Individual
•
Filing: 1972-06-05
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Granted: 1975-07-15
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Expires: 1992-06-05
Abstract
Abstract Improvements in apparatus for and the method of plasma arc remelting of a metal charge are disclosed and claimed. A plurality of plasma torch means are adjustably mounted in a plasma remelting chamber. These torches may be adjusted in order to change the position of the plasma arcs with respect to each other and to the mold contained in the chamber. The metal charge to be melted can be in the form of a metal blank which is moved axially into the plasma arcs for melting and which is rotated with respect to the plasma arcs during melting. From two to six adjustable torch means are employed for use within the plasma chamber.
Inventors
- 👤 Boris Evgenievich Paton
- 👤 Victor Iosifovich Lakomsky
- 👤 Anatoli Ivanovich Chvertko
- 👤 Grigori Bogratovich Asovants
- 👤 Oleg Semenovich Zabarilo
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:08
CPC Classifications
C; C22; C22B; C22B9/00; C22B9/16; C22B9/22; C22B9/226; H; H05; H05B; H05B7/00
Claims Analysis
Total Claims: 41
Claim 1
Independent Claim
133 words
A plasma arc remelting installation for producing ingots comprising a hermetically sealable chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means carried by said chamber and positioned above said mold, and means mounting at least one of said plasma arc torch means in said chamber for adjustable positioning of the torch means along its axis and for selective universally rockable positioning about a given fixed point on its axis to enable movement of the plasma arc therefrom during remelting with respect to said mold; an electric power supply source, said torch means connectable to so as to supply plasma to melt metal; and a metal charge arranged to be melted in the plasma arcs and the molten metal therefrom solidified in said mold to form an ingot.
Claim 2
Dependent Claim
133 words
A plasma arc remelting installation for producing ingots comprising a hermetically sealable chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means carried by said chamber and positioned above said mold, and means mounting at least one of said plasma arc torch means in said chamber for adjustable positioning of the torch means along its axis and for selective universally rockable positioning about a given fixed point on its axis to enable movement of the plasma arc therefrom during remelting with respect to said mold; an electric power supply source, said torch means connectable to so as to supply plasma to melt metal; and a metal charge arranged to be melted in the plasma arcs and the molten metal therefrom solidified in said mold to form an ingot.
Claim 3
Dependent Claim
49 words
A plasma arc remelting installation as defined by claim 1 wherein said plurality of plasma arc torch means is arranged about the axis of said mold and positioned within said chamber to direct their plasma arcs in a direction at an acute angle to the axis of the mold.
Claim 4
Dependent Claim
21 words
A plasma arc remelting installation as defined by claim 1 wherein said mold is connectable to said electric power supply source.
Claim 5
Dependent Claim
30 words
A plasma arc remelting installation as defined by claim 1 wherein said metal charge comprises a metal blank, and wherein said blank is positioned coaxially with and above said mold.
Claim 6
Dependent Claim
24 words
A plasma arc remelting installation as defined by claim 1 wherein said metal charge comprises metal particles released within said chamber from a hopper.
Claim 7
Dependent Claim
47 words
A plasma arc remelting installation as defined by claim 1 wherein said adjustably mounted torch means includes means enabling positioning to direct its plasma in a direction having at least a tangential component so as to cause horizontal rotary motion in the molten metal in said mold.
Claim 8
Dependent Claim
27 words
A plasma arc remelting installation as defined by claim 1 wherein a coolant system is provided for said mold and said plurality of plasma arc torch means.
Claim 9
Dependent Claim
28 words
A plasma arc remelting installation as defined by claim 7 wherein up to about 80% of the heat released by the solidifying ingot is removed by said mold.
Claim 10
Dependent Claim
19 words
A plasma arc remelting installation as defined by claim 1 wherein said mold forms an ingot of circular cross-section.
Claim 11
Dependent Claim
21 words
A plasma arc remelting installation as defined by claim 1 wherein said mold forms an ingot of rectangular or square cross-section.
Claim 12
Dependent Claim
21 words
A plasma arc remelting installation as defined by claim 1 wherein said mold forms an ingot of nonrectilinear or polyhedral cross-section.
Claim 13
Dependent Claim
30 words
A plasma arc remelting installation as defined by claim 1 wherein the number of plasma arc torch means positioned above said mold is between the numbers of 2 to 9.
Claim 14
Dependent Claim
33 words
A plasma arc remelting installation as defined by claim 1 wherein said electric power supply source comprises one or more three phase alternating current transformers having secondary coils arranged in a star winding.
Claim 15
Dependent Claim
21 words
A plasma arc remelting installation as defined by claim 13 wherein the neutral points of said transformers are insulated from ground.
Claim 16
Dependent Claim
50 words
A plasma arc remelting installation as defined by claim 13 wherein there are six plasma arc torches radially arranged within said chamber above said mold and alternately connected to the secondary windings of two transformers and the neutral points of said two transformers being electrically connected and insulated from ground.
Claim 17
Dependent Claim
20 words
A plasma arc remelting installation as defined by claim 1 wherein said electric power supply source operates on direct current.
Claim 18
Dependent Claim
113 words
A plasma arc remelting installation for producing ingots comprising a hermetically sealable chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means carried by said chamber and positioned above said mold; an electric power supply source connectable to said torch means so as to supply plasma to melt metal; a metal blank arranged to be melted in the plasma arc and the molten metal therefrom solidified in said mold; and a feeding mechanism for moving said metal blank into the plasma arcs, said feeding mechanism adapted to selectively rotate said blank axially with respect to the plasma arcs and move said blank in the direction of its axis.
Claim 19
Dependent Claim
113 words
A plasma arc remelting installation for producing ingots comprising a hermetically sealable chamber; an ingot-forming mold contained in said chamber; a plurality of plasma arc torch means carried by said chamber and positioned above said mold; an electric power supply source connectable to said torch means so as to supply plasma to melt metal; a metal blank arranged to be melted in the plasma arc and the molten metal therefrom solidified in said mold; and a feeding mechanism for moving said metal blank into the plasma arcs, said feeding mechanism adapted to selectively rotate said blank axially with respect to the plasma arcs and move said blank in the direction of its axis.
Claim 20
Dependent Claim
37 words
A plasma arc remelting installation as defined by claim 17 wherein at least one of said torch means is adjustably mounted in said chamber to enable movement of the plasma arc therefrom with respect to said mold.
Claim 21
Dependent Claim
37 words
A plasma arc remelting installation as defined by claim 18 wherein said one plasma arc torch means is adjustable for movement along its axis and for variable axial positioning about a given fixed point on its axis.
Claim 22
Dependent Claim
48 words
A plasma arc remelting installation as defined by claim 17 wherein said feeding mechanism comprises a rod for attachment to said metal blank and a control mechanism adapted for feeding said rod axially downward and for selectively rotating said rod with respect to said plasma arc torch means.
Claim 23
Dependent Claim
45 words
A plasma arc remelting installation as defined by claim 17 wherein said feeding mechanism comprises a cable means for moving said blank in the direction of its axis and a rotation drive means for selectively rotating said blank axially with respect to the plasma arcs.
Claim 24
Dependent Claim
26 words
A plasma arc remelting installation as defined by claim 17 wherein said feeding mechanism comprises a train of spur gears, worm gears, and a control device.
Claim 25
Dependent Claim
77 words
A plasma arc remelting installation as defined by claim 17 wherein six plasma arc torch means are positioned above said mold, and wherein a carriage for supporting the ingot formed within said mold is provided, and further provided with an ingot extracting motor mechanism attached to said carriage, a system for evacuating said chamber and a system for recycling cleaned gas through said chamber, and a water cooling system for said torches, said mold, said sealable chamber.
Claim 26
Dependent Claim
35 words
A plasma arc remelting installation as defined by claim 17 wherein said electric power supply source, and said feeding mechanism are controlled by a remote control system which is physically removed from said sealable chamber.
Claim 27
Dependent Claim
119 words
A plasma arc remelting method for producing ingots comprising the steps of: suspending a metal blank within a hermetically sealable chamber from a feeding mechanism, removing the air in the chamber to create a vacuum in the order of 10 2mmHg., scavaging the chamber with an inert gas, supplying electric power to a plurality of plasma arc torch means positioned above a mold contained in the chamber, melting liquid metal from the metal blank and solidifying the melted metal in the mold, rotating and feeding the metal blank axially downwardly as it is melted by the plasma arcs, simultaneously extracting from the mold the formed ingot while maintaining the liquid metal level at a constant position within the mold.
Claim 28
Dependent Claim
119 words
A plasma arc remelting method for producing ingots comprising the steps of: suspending a metal blank within a hermetically sealable chamber from a feeding mechanism, removing the air in the chamber to create a vacuum in the order of 10 2mmHg., scavaging the chamber with an inert gas, supplying electric power to a plurality of plasma arc torch means positioned above a mold contained in the chamber, melting liquid metal from the metal blank and solidifying the melted metal in the mold, rotating and feeding the metal blank axially downwardly as it is melted by the plasma arcs, simultaneously extracting from the mold the formed ingot while maintaining the liquid metal level at a constant position within the mold.
Claim 29
Dependent Claim
57 words
A plasma arc remelting method as defined by claim 25 comprising the additional step of adjusting the position of one or more of the plasma arc torch means with respect to the mold and the metal blank to allow even heat distribution and uniform melting of the metal blank and solidification of the ingot within the mold.
Claim 30
Dependent Claim
56 words
A plasma arc remelting method as defined by claim 25 comprising the preliminary steps of opening a side hatch in the hermetically sealable chamber, loading the metal blank into the chamber through the side hatch while in a vertical position, and extRacting the spent metal blank stub through the same side hatch following the remelting operation.
Claim 31
Dependent Claim
24 words
A plasma arc remelting method as defined by claim 25 wherein flux is added to the mold during melting from a hermetically sealed hopper.
Claim 32
Dependent Claim
41 words
A plasma arc remelting method as defined by claim 25 wherein viewing ports located in the wall of the sealable chamber are cleaned of condensed materials during melting in order to provide viewing for adjustment of the plasma arc torch positions.
Claim 33
Dependent Claim
52 words
A plasma arc remelting method as defined by claim 25 wherein the heating of the molten metal pool contained within the mold by the plasma arcs generates free-convection macroflows resulting in stirring of the metallic bath, thereby promoting chemical homogenization of the molten metal and lower inclusion content in the ingot metal.
Claim 34
Dependent Claim
44 words
A plasma arc remelting method as defined by claim 25, wherein the molten metal melted by the plasma arcs is formed as a flat shallow bath within said mold having a maximum depth dimension to maximum cross sectional dimension of about 1/5 to 1/10.
Claim 35
Dependent Claim
32 words
A plasma arc remelting method as defined by claim 31, wherein the molten metal bath formed in said mold is maintained with a temperature gradient of up to about 200*C. per centimeter.
Claim 36
Dependent Claim
30 words
A plasma arc remelting method as defined by claim 25, wherein said plasma arc torch means are operated within an operating current range of about from 500 to 6000 amperes.
Claim 37
Dependent Claim
27 words
A plasma arc remelting method as defined by claim 25, wherein said plasma arc torch means are operated at potentials of about from 40 to 250 volts.
Claim 38
Dependent Claim
30 words
A plasma arc remelting method as defined by claim 25, wherein said plasma arc torch means are each operated at a power level of about from 150 to 3,000 kilowatts.
Claim 39
Dependent Claim
36 words
A plasma arc remelting method as defined by claim 25, wherein said method produces a plasma arc remelted ingot having low inclusion content and in a weight range of about from 50 kg. to 5,000 kg.
Claim 40
Dependent Claim
154 words
A plasma arc remelting method for producing ingots comprising the steps of: suspending a metal blank within a hermetically sealable chamber from a feeding mechanism, removing the air in the chamber to create a vacuum in the order of 10 2mmHg., scavaging the chamber with an inert gas, supplying electric power to a plurality of plasma arc torch means positioned above a mold contained in the chamber, melting liquid metal from the metal blank and solidifying the melted metal in the mold, rotating and feeding the metal blank with a rotational oscillation about its vertical axis as it is melted by the plasma arcs, the oscillatory movement of the metal blank being over an angular increment equal to or greater than 360*/n, where n is the number of plasma arc torch means, and simultaneously extracting from the mold the formed ingot while maintaining the liquid metal level at a constant position within the mold.
Claim 41
Dependent Claim
154 words
A plasma arc remelting method for producing ingots comprising the steps of: suspending a metal blank within a hermetically sealable chamber from a feeding mechanism, removing the air in the chamber to create a vacuum in the order of 10 2mmHg., scavaging the chamber with an inert gas, supplying electric power to a plurality of plasma arc torch means positioned above a mold contained in the chamber, melting liquid metal from the metal blank and solidifying the melted metal in the mold, rotating and feeding the metal blank with a rotational oscillation about its vertical axis as it is melted by the plasma arcs, the oscillatory movement of the metal blank being over an angular increment equal to or greater than 360*/n, where n is the number of plasma arc torch means, and simultaneously extracting from the mold the formed ingot while maintaining the liquid metal level at a constant position within the mold.
References Cited (Backward Citations)
US2762093A
Cited
US3237254A
Cited
US3312566A
Cited
US3344839A
Cited
US3625660A
Cited
US3496280A
Cited
US3683997A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-14 | 1979-01-13 | 1979-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-14 | 1983-01-13 | 1983-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-14 | 1987-01-13 | 1987-07-15 | $7700.00 | Window Closed / Lapsed |