US3684001A - Electroslag furnace eliminating magnetic stirring effect - Google Patents

Electroslag furnace eliminating magnetic stirring effect Download PDF

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Publication number
US3684001A
US3684001A US36147A US3684001DA US3684001A US 3684001 A US3684001 A US 3684001A US 36147 A US36147 A US 36147A US 3684001D A US3684001D A US 3684001DA US 3684001 A US3684001 A US 3684001A
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United States
Prior art keywords
electrode
crucible
head
conductor
base
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Expired - Lifetime
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US36147A
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English (en)
Inventor
Patrick J Wooding
Raymond John Roberts
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Consarc Corp
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Consarc Corp
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Assigned to COMMERCE BANK, N.A. reassignment COMMERCE BANK, N.A. NEGATIVE PLEDGE Assignors: WOODING TECHNOLOGIES LIMITED
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    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00—Heating by electric discharge
    • H05B7/02—Details
    • H05B7/10—Mountings, supports, terminals or arrangements for feeding or guiding electrodes
    • H05B7/101—Mountings, supports or terminals at head of electrode, i.e. at the end remote from the arc
    • H05B7/102—Mountings, supports or terminals at head of electrode, i.e. at the end remote from the arc specially adapted for consumable electrodes

Definitions

  • This invention relates to a power connection for an electroslag furnace. More particularly this invention relates to a power connection which is the equivalent of a coaxial conductor so as to eliminate the various deleterious effects of magnetic fields.
  • the present invention relates principally to apparatus for distributing the current in an electroslag furnace to eliminate the stirring effects of the magnetic field on the pool of molten metal.
  • One of the primary advantages of consumable melting is the progressive solidification of the ingot.
  • the typical consumable electrode furnace first forms a pool of fused metal which enlarges to a determined volume and thereafter remains fairly constant while progressive solidification takes place at the bottom of the pool.
  • Another factor which has been found to influence greatly the quality of the resultant ingot is the degree of stirring or agitation of the molten metal pool. It has been found that for many materials, particularly those with high alloy contents which are subject to alloy segregation, the most uniform ingot structure and the highest ingot quality are obtained when the molten metal pool is completely or almost completely quiescent.
  • the objects of the present invention are achieved by providing a coaxial conductor or the equivalent thereof for supplying power to an electroslag furnace.
  • the purpose for using a coaxial conductor design can best be understood by analyzing the nature of the magnetic forces produced in a typical electroslag furnace.
  • the electrode which is to be melted in such a process must be smaller in diameter than the crucible which will contain the forming ingot and its associated molten slag and molten metal pool.
  • this diameter difference inevitably results in horizontal components of current flowing radially outwards towards the perimeter of the mould or radially inward towards the electrode depending on the polarity of the applied voltage.
  • the skin effect (for alternating current) is much more pronounced in the molten metal pool than in the slag pool, because of the difference in their electrical resistances. This means that the tendency of the alternating current to flow on the outside is much more pronounced in the molten metal pool than it is in the molten slag pool.
  • displacement of the electrode is provided for, by the incorporation of a sliding contact system.
  • a number of discrete conductors are used to obtain the effect of a coaxial return conductor. It has been found in practice that four or more conductors are required to give the same effect as a continuous return conductor but the use of three or even two conductors represents an improvement over the conventional system.
  • the object of the present invention is directed to providing an electroslag furnace for use with alternating or direct current having the requisite equivalent of a coaxial conductor system to eliminate deleterious magnetic stirring of the molten slag and metal pools.
  • a further object of the present invention is directed to providing an electroslag furnace having the requisite equivalent of a coaxial conductor system which results in a high operating power factor when used with alternating current.
  • Yet another object of the present invention is directed to providing an AC electroslag furnace having the requisite equivalent of a coaxial conductor system of fixed length in which the reactive voltage drop remains substantially unchanged as the electrode is consumed.
  • a further object of the present invention is directed to providing an AC electroslag furnace having the equivalent of a coaxial conductor system which substantially eliminates eddy current heating of the steel support structure of the furnace and adjacent equipment.
  • an electroslag furnace with a power connection equivalent to a coaxial conductor. This is accomplished by providing a return conductor extending substantially vertically from the base of the crucible.
  • the return conductor which is preferably a zone by the flexible conductors used to make an electrical connection between the coaxial configuration and the electrical power supply.
  • FIG. 1 is a side elevation view of the furnace with the head rotated out of alignment with the crucible.
  • FIG. 2 is a partial sectional view of the furnace showing an electrode and a partially fonned ingot within the furnace.
  • FIG. 3 is a plan view of the furnace illustrated in FIG. 1.
  • FIG. 4 is a partial sectional view of a second embodiment of the furnace.
  • the drawings show a consumable electrode furnace of the electroslag type designated generally as 10.
  • the furnace has been greatly simplified for purposes of describing this invention. Thus, such parts as the control console, slag feeder, and process starting equipment have not been shown since they form no part of the present invention.
  • an electroslag furnace having a crucible l2 resting upon a base 14.
  • the crucible is fixed adjacent its top by a steel box frame 16.
  • the crucible 12 includes an outer water jacket 18 for cooling the walls thereof.
  • the crucible also includes an appropriate water cooled stool 20 at its base which is conventional in such crucibles.
  • a furnace head 22 is reciprocably and rotatably supported above the crucible 12 by means of a large pin 24 extending through the head and fixed within an appropriate bearing 26 fixed to the block 28.
  • the pin 24 also extends through a sleeve 30 which provides additional support for the furnace head 22.
  • the block 28 and the sleeve 30 are supported by column 32.
  • the pin 24 can be lifted by hydraulic cylinder 97 to provide reciprocal as well as rotational motion of the head 22.
  • a water cooled conductor34 is supported on the head 22 by hydraulic cylinders 36 which are fixed to the plate 38. Hydraulic cylinders 36 provide a means of rams 40 and 42 which are reciprocated by hydraulic pressure applied to pistons fixed at their ends within the cylinders 44 and 46. Thus, the water cooled conductor 34 can be reciprocated with respect to the head 22, and also the crucible 12, by appropriate control of the position of the rams 40 and 42.
  • the water cooled conductor 34 supplies current from one terminal of a power supply 200 to the electrode 50 to be remelted within the furnace.
  • the electrode itself is supported at the end of the water cooled conductor by an electrode clamp 48. This is best illustrated in FIG. 2 wherein the electrode 50 is shown fixed in position on the clamp 48.
  • Electric power is supplied to the water cooled conductor 34 by a sliding contact assembly 52 mounted within the head 22.
  • the sliding contact assembly 52 is connected to a power supply 200 by a pair of water cooled conductors 54.
  • each of the return conductors 58-64 is divided into two sections. The first section is the lower or crucible section identified as 66, 68, 70 or 72. Each crucible section is electrically connected to the stool by means of appropriate connecting blocks 74, 76 and 78.
  • the upper portion of each return conductor 58-64 is defined by one of the head sections 82, 84, 86 and 88. The upper or head sections of the return conductors are fixed within the head 22 and connected to a pair of water cooled conductors 90 which in turn are connected to the power supply.
  • the head sections of the return conductors are shown in FIG. 1 disconnected from the crucible sections so that the head 22 can be rotated out of alignment with the crucible 12. This is the position of the head 22 illustrated in FIG. 3.
  • the head is rotated to the illustrated position so that a completed ingot can be removed from the crucible 12. This also permits removal and replacement of the crucible 12.
  • a fresh electrode is positioned within the crucible and the head 22 thereafter rotated into position over the crucible 12.
  • the electrode 50 is then fixed to the electrode clamp 48 so that it is properly aligned within the crucible.
  • the head 22 is lowered so that each head section 82-88 mates with a corresponding crucible section 66-72 of the return conductors 5.
  • FIG. 2 This is illustrated in FIG. 2 wherein a male fitting 92 protruding from each of the head sections 82-88 is fitted within a cup-like female fitting 94 fixed to the end of the crucible section 66-72.
  • Appropriate locking means 96 fix the fittings in mating relationship and provide good electrical contact.
  • the sections of the return conductors 58-64 provide a return for completing the electrical circuit of the furnace 10.
  • the return conductors 58-64 are spaced at equal distances about the circumference of the crucible 12. Moreover, they extend upwardly parallel to the axis of the crucible 1'2 and are preferably kept as close to the crucible as possible. As thus positioned, they form the equivalent of the outer sheath of a coaxial cable.
  • the water cooled conductor 34 and clamp 48 may be regarded as the internal concentric conductor. Also included in the internal conductor in an operating furnace are the molten slag pool 98, the molten metal pool 56, and ingot 53.
  • the return conductors 58-64 provide a magnetic field which is equal and opposite to the magnetic field generated by the conductor 34, clamp 48, electrode 50, molten slag 98, molten metal 56, and ingot 53.
  • the magnetic field external to the furnace is cancelled.
  • the coaxial positioning of the return conductors 5 to the internal concentric conductor (34, 48, 50, 98, 56, 53) eliminates all vertical components of magnetic flux and hence all stirring forces.
  • return conductors are provided. However, it should be noted that three conductors may suffice. Moreover, it may also be desirable to provide more than four return conductors. Four conductors, however, sufficiently control the magnetic field to provide the requisite equivalent of a coaxial configuration for all practical purposes.
  • the coaxial effect is carried well above the melt zone 56 all the way into the head 22. It is only at the top of the head that conductors 54 and are displaced horizontally with respect to the furnace. Since the conductors 54 and 90 are kept close together, that is, they are laced their magnetic fields produced in the region of the melt zone are mutually cancelling. The net result is that there is very little reactive voltage drop in the circuit when AC power is used for melting. Indeed, a furnace constructed in accordance with the principles of this invention will have a much better power factor than other furnaces.
  • the water cooled conductor 34 and electrode clamp 48 are used as a means to make electrical connection to the electrode 50.
  • Power is supplied to the conductor 34 through the sliding contact 52.
  • the foreshortening of the electrode 50 is taken up by the displacement of the conductor 34 downwardly toward and into the crucible 12.
  • the length of the current carrying internal conductor of the coaxial configuration does not decrease as the electrode 50 is melted. Since the length of the coaxial configuration remains fixed even though the electrode is being consumed, the reactive voltage drop in the entire circuit is fixed at any selected current level. Accordingly, there is no requirement for adjusting or compensating the power supply voltage to maintain thermal and electrical equilibrium in the melt zone.
  • the crucible itself can be used as a return conductor as shown in FIG. 4.
  • the crucible 18 is electrically connected to the base 20' as well as to the head 22.
  • the connection to the head may be by conductor means which are coaxial with the electrode 50'.
  • the electrode 50' is connected to the power supply by conductors 54' and a sliding contact similar to contact 52 in FIG. 2. These conductors are electrically insulated from head 22'.
  • the head 22 may be connected to the power supply by return conductors 90.
  • a power connection for an electroslag furnace said furnace including a crucible, a crucible base, an electrode support and positioning means, and means to make connections to the electrode and the base from a power supply
  • the improvement comprising a return conductor electrically connected to the base, said return conductor being coaxially disposed around the crucible and the power connection to the electrode, the electrode, the molten slag pool, the molten metal pool, and the ingot to define a coaxial configuration, said coaxial configuration being continued to a point sufficiently above the molten slag and molten metal pools that negligible vertical components of magnetic fields will be generated in the melt zone by a conductor loop 7 used to make an electrical connection between the coaxial configuration and an electrical power supply.
  • a power connection in accordance with claim 1 rent-carrying coaxial configuration does not decrease as the electrode is melted.
  • a power connection in accordance with claim 4 wherein said return conductor comprises at least three discrete conductors substantially equally spacedabout the perimeter of the crucible.
  • said furnace including a crucible, acrucible base, an
  • electrode support and positioning means a power supply, and means to make power connections to the electrode and the base, the improvement comprising a return conductor electrically connnected to the base,
  • said return conductor being coaxially disposed around the crucible and the power connection to the electrode, the electrode, the molten slag pool, the molten metal pool, and the ingot to define a coaxial configuration
  • said furnace including a crucible, a crucible base, an
  • the improvement comprising a return conductor electrically connected to the base, said return conductor being coaxially disposed around the-power connection to the electrode the electrode, e
  • said return conductor including the wall of said crucible extending generally vertically upward from said base,'a separable head, means for making and unmakingelectrical connection between said head and said crucible wall so that said head may be displaced to permit loading and unloading of crucibles, electrodes and ingots, said head defining a second conductor means to continue the return conductor vertically upwards to a first terminal point located on said head, said electrode support and positioning means passing through said head, sliding contact means for making an electrical connection between the electrode support means and a second tenninal point insulated from said first terminal point, and laced, flexible power cables for making electrical connection between said terminal points and said power supply.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Furnace Details (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
US36147A 1970-05-11 1970-05-11 Electroslag furnace eliminating magnetic stirring effect Expired - Lifetime US3684001A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US3614770A 1970-05-11 1970-05-11

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US3684001A true US3684001A (en) 1972-08-15

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US (1) US3684001A (enrdf_load_stackoverflow)
AT (1) AT314108B (enrdf_load_stackoverflow)
CA (1) CA938646A (enrdf_load_stackoverflow)
DE (1) DE2123368B2 (enrdf_load_stackoverflow)
FR (1) FR2091475A5 (enrdf_load_stackoverflow)
GB (1) GB1312035A (enrdf_load_stackoverflow)
SE (1) SE382739B (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2833695A1 (de) * 1978-08-01 1980-02-14 Leybold Heraeus Gmbh & Co Kg Elektroschlackeumschmelzanlage mit koaxialen strompfaden
US4280550A (en) * 1980-02-11 1981-07-28 Consarc Corporation Electroslag remelting furnace with improved power connection
GB2343242A (en) * 1998-08-29 2000-05-03 Ald Vacuum Techn Gmbh Electroslag melting plant
US8110772B1 (en) * 2009-06-03 2012-02-07 Bong William L System and method for multi-pass computer controlled narrow-gap electroslag welding applications

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2746256C3 (de) * 1977-10-14 1981-08-13 Institut elektrosvarki imeni E.O. Patona Akademii Nauk Ukrainskoj SSR, Kiev Ringförmige Kokille für Anlagen zum Elektroschlacke-Umschmelzen bzw. Auftragschweißen von Metallen
FR2420575A1 (fr) * 1978-03-22 1979-10-19 Heurtey Metallurgie Perfectionnement apportes aux installations de refusion sous laitier electroconducteur
DE2902095C2 (de) * 1979-01-19 1986-07-17 Skw Trostberg Ag, 8223 Trostberg Einbrennlack auf Basis einer Polyvinylidenfluoridlösung, Verfahren zu seiner Herstellung und dessen Verwendung zum Beschichten von Kunststoffen
AT373802B (de) * 1981-11-13 1984-02-27 Ver Edelstahlwerke Ag Vorrichtung zum elektroschlacke-umschmelzen
DE3912928A1 (de) * 1989-04-20 1990-10-25 Leybold Ag Geschlossener umschmelzofen mit einer elektrischen verbindung von ofenoberteil und ofenunterteil

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2951890A (en) * 1957-04-11 1960-09-06 Ici Ltd Method of operating an electric arc furnace
US3067473A (en) * 1960-03-29 1962-12-11 Firth Sterling Inc Producing superior quality ingot metal
US3072982A (en) * 1953-07-13 1963-01-15 Westinghouse Electric Corp Method of producing sound and homogeneous ingots
US3379238A (en) * 1965-05-26 1968-04-23 Lectromelt Corp Polyphase electric furnace for molding ingots
US3439103A (en) * 1967-04-28 1969-04-15 Boehler & Co Ag Geb Electrode assembly for electric slag melting
US3476171A (en) * 1967-02-14 1969-11-04 Reactive Metals Inc Method for melting refractory metal
US3510562A (en) * 1968-09-17 1970-05-05 Qualitats Und Edelstahl Kom Ve Equipment for electroslag remelting of metals

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3072982A (en) * 1953-07-13 1963-01-15 Westinghouse Electric Corp Method of producing sound and homogeneous ingots
US2951890A (en) * 1957-04-11 1960-09-06 Ici Ltd Method of operating an electric arc furnace
US3067473A (en) * 1960-03-29 1962-12-11 Firth Sterling Inc Producing superior quality ingot metal
US3379238A (en) * 1965-05-26 1968-04-23 Lectromelt Corp Polyphase electric furnace for molding ingots
US3476171A (en) * 1967-02-14 1969-11-04 Reactive Metals Inc Method for melting refractory metal
US3439103A (en) * 1967-04-28 1969-04-15 Boehler & Co Ag Geb Electrode assembly for electric slag melting
US3510562A (en) * 1968-09-17 1970-05-05 Qualitats Und Edelstahl Kom Ve Equipment for electroslag remelting of metals

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2833695A1 (de) * 1978-08-01 1980-02-14 Leybold Heraeus Gmbh & Co Kg Elektroschlackeumschmelzanlage mit koaxialen strompfaden
US4262159A (en) * 1978-08-01 1981-04-14 Leybold-Heraeus Gmbh Electroslag remelting apparatus with coaxial current paths
US4280550A (en) * 1980-02-11 1981-07-28 Consarc Corporation Electroslag remelting furnace with improved power connection
GB2343242A (en) * 1998-08-29 2000-05-03 Ald Vacuum Techn Gmbh Electroslag melting plant
DE19839432C2 (de) * 1998-08-29 2000-12-07 Ald Vacuum Techn Ag Elektro-Schmelzanlage
GB2343242B (en) * 1998-08-29 2002-12-04 Ald Vacuum Techn Gmbh Electric melting plant
US8110772B1 (en) * 2009-06-03 2012-02-07 Bong William L System and method for multi-pass computer controlled narrow-gap electroslag welding applications

Also Published As

Publication number Publication date
FR2091475A5 (enrdf_load_stackoverflow) 1972-01-14
DE2123368A1 (de) 1971-12-23
CA938646A (en) 1973-12-18
AT314108B (de) 1974-03-25
SE382739B (sv) 1976-02-09
DE2123368B2 (de) 1977-03-03
GB1312035A (en) 1973-04-04

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AS Assignment

Owner name: COMMERCE BANK, N.A., NEW JERSEY

Free format text: NEGATIVE PLEDGE;ASSIGNOR:WOODING TECHNOLOGIES LIMITED;REEL/FRAME:009790/0719

Effective date: 19990111