US2912476A - Casting furnace - Google Patents

Description

NOV, 10, 1959 w A7 sc p 2,912,476

CASTING FURNACE 3 Sheets-Sheet 1 Filed April 22, 1957 mmvron Mill's HJIschaff Z1 5" M W Nov. 10, 1959 w. A. ASCHOFF CASTING FURNACE 3 Sheets-Sheet 2 Filed April 22, 1957 S m km. WM d W k m c A m S Q\ V m u m L: S m \Q\ W Y R k w& a NQ mw 6% vi n n v 0 \Q\ Q \LQW 5: h a AN 4 R mm mm Q mi N1 NOV. 10, 1959 w, ASCHQFF 2,912,476 V CASTING FURNACE 3 Sheets-Sheet 3 Filed April 22. 1957 l2? Willis .Qfl'schoff fi a! CASTING FURNACE -Willis A. Aschotr, Albany, reg., assignor to Oregon Metallurgical Corporation, Albany, 0reg., a corporation of Oregon Application April 22, 1957, Serial No. 654,292 13 Claims. (Cl. 13-

This invention relates to casting furnaces and more particularly to casting furnaces useful for the production of metal castings from refractory metals wherein the metal castings are prepared under carefully controlled operating conditions. I e

In preparing castings frommetals such as titanium and zirconium, the conditions under which the metal is reduced to a molten state, and subsequently cooled, must be carefully controlled to eliminate contamination ofthe metal and/or destruction of the apparatus employed. While relatively stable at lower temperatures, titanium, for example, quickly reacts with such materials as oxygen and nitrogen at elevated temperatures with the formation of compounds which deleteriously affect the properties of the metal. Consequently, titanium is usually handled at elevated temperatures either in a vacuum or in the presence of an inert gas such as argon or helium.

In addition to the atmospheric conditions. employed, the materials and temperatures of the vessels and equipment used during a melt must also be carefully selected. Many of the ordinary metals, for instance, react with titanium at elevated temperatures contaminating the metal and impairing its physical properties. Further, the relatively high melting point of titanium, which is approximately 1800 (3., requires that some form of cooling be supplied any vessel holding the molten metal if the vessel is comprised of material having a melting point lower than that of titanium.'

A methodpresently used for preparing titanium and zirconium castings comprises heating the metal by means of an electric arc in a sealed furnace chamber from which air has been evacuated. Considering titanium, for example, the titanium isfirst formed into, an elongated bar which functions as one of the pair of electrodes necessary for producing an electric arc. The electric arc is generated between the end of the titanium bar which is melted or consumed during the process and the vessel in which the molten titanium is collected, this vessel constituting the other of the pair of electrodes in the process. Such a process uses relatively large amounts of electric current delivered at relatively low voltages, a typical operation employing a direct current of 10,000

amps. at a voltage of approximately 30 volts. I Molten metal is poured from the collecting vessel into appropriate molds as soon as possible after terminating the electric arc to prevent the metal from freezing within the vessel. The metal casting is then allowed to cool preferably with the introduction of an inert gas into the furnace chamber which facilitates cooling without reacting with hot titanium.

Because of the relatively large electrical current employed, the electrical components of the electrical circuit producing the arc in such a furnace preferably are made of a highly conductive material such as copper to eliminate power losses in these components. The rod or stinger normally used for lowering the titanium electrode into" the furnace also serves to'deliver current to between this vessel and one of the pair of power 2,912,476 Patented Nov. 10, 1959 ICE fore is conventionally comprised of copper. Similarly, the circuit for the other electrode in the furnace, comprising the vessel holding the melt and the connections pp y conductors in a plant, is also normally comprised of copper. Copper has a melting point considerably below that of titanium so a copper vessel holding molten titanium must be cooled to prevent destruction of the vessel. A water circulating system is normally used for this purpose. In practice, the initial titanium melt forms .a solidified hollow skull around the interior of the vessel which insulates the vessel from the pool of molten titanium collected in the skull. l

The creation intermittently of a vacuum withinthe furnace, the necessity for having an electrical path of low resistance for the current producing the arc in the furnace, and the requirement that the vessel holding the .melt be cooled during operation of the furnace, has

created a number of problems. The vessel or crucible holding the melt is normally pivotally mounted within a furnace chamber to enable a pour to be made by tilting the vessel. Furnace constructions heretofore have vused flexible conductors interconnecting the vessel and the power supply in a plant to accommodate pivotal movement of the vessel. The conduit systems employed for delivering coolant to the vessel have either used flexible hosing or resorted to swivel connections within the furnace to permitpivoting of the vessel. Further, the mechanism used for tilting the vessel has customarily been mounted within the interior of the furnace to eliminate difiiculties in maintaining a vacuum in the furnace. Such constructions, however, have been troublesome by reason of the operating conditions within the furnace. Molten metal splashings deposited upon the flexible electrical conductors cause the conductors to become brittle and, by so doing, severely limit the life of the conductors. Flexible hose connections delivering coolant to the vessel have been a constant source of potential leaks causing shutdowns and wasted man hours. The presence of swivel joints and moving mechanical parts has been undesirable since metal particles have tended to lodge themselves within the mechanisms, creating frequent failures. This latter problem is particularly acute because of the breathingaction which takes place in mechanisms such'as swivel joints created by sequentially creating a vacuum and then restoring atmospheric pressure within the furnace.

Generally, it is an object of this invention to provide a novel means for supporting and canting a ladle or crucible within a casting furnace which eliminates the necessity of using flexible conductors or hosing within the furnace. a

More specifically, it is an object of this invention to provide a casting'fur'nace for producing metal castings as described above, wherein the ladle or crucible collecting the molten metal for the castings iscanted or tilted within the furnace by means of a canting arm atthe titanium electrode carried atits lower end and therefixed tothe ladle and projecting outwardly to the exterior of the furnace, and to provide a novel means for rotating such a canting arm.

A further object of this invention is to provide such a furnace construction wherein the canting arm, together with the ladle, constitutes a portion of the electrical circuit for the production of the electric arc with,- in the furnace, the connection between the canting arm and the electrical power supply in a plant being established outside the furnace.

Further, it is an object of this invention to provide such an electric arc furnace wherein the canting arm includes passage means supplying a coolant to the ladle mounted within the furnace thereby eliminating the: need for swivel joints withm' the furnace.

'duc'ing an electric are within the portions is .comprised of a pair of furnacewherein the ladle'or crucible for'the furnace'is -rotatably supported within the furnace by means of a pair-ofaxially aligned, tubularshaft'sections disposed on either side of the ladle with opposite ends of the shaft sections protruding outside v.thefurnace, the shaft sections constituting a portion of the electric circuit profurnaee, providing discharge and'exhaust connections for coolant'supplied to the ladle, and providing a motion transmitting mechanism for imparting a tilt to-the ladle when a pouris to be made.

These and other objects and-advantages are attained thepresentinvention, various novel features of which will become more fully apparent asthefollowing description is read in conjunction with the accompanying drawings wherein:

Fig. -1 is aside'view ofa casting furnace embodying the present invention;

Fig. 2 is'asectionview-along the line *22"in'Fig. 1; "Fig. 3 is an enlarged section view along'the line33 in Fig. 2 showing the constructionused 'forraflixing one cfthe canting arms or shafts to the ladle "Within the furnace;

Fig. -4 is an enlarged section view-along'the line'44 in Fig. '1, illustrating a pressure seal employed in the "furnace;

Fig. 5 is an enlarged section view along the'line 5-5 in Fig. 1;and

Fig. "6 is a schematic view of'the means employedfor rotating the ladle or crucible within the furnace.

In the drawings, where an embodiment of this invention-is illustrated, 9 indicates generally an electric arc furnace comprising a' furnace body portion indicated at 10, a shielding sleeve or stack 11 aflixed to the top of the furnace body and projecting vertically upwardly therefrom, and a rod or stinger .12 mounted for reciprocation up and down in stack 11. Stinger 1'2'has a consumable metal electrode such as .a .titaniumelectrode '13 secured to and in electrical contact with the lower end of stinger '12. This connection may be made in a conventional manner such as by securing electrode '13 onto a threaded 'stud carried at the lower endof stinger 12. Stinger 12 provides a means for lowering the titanium electrode downwardly within the furnace as the electrode is progressively"meltedaawayby the heat gen- -erated in the electric are.

As illustrated, body portion of the furnaceiseomprised of furnace shell portions 16, 17,, andj18, which may be disassembled from each other to accommodate entry into the interior of the furnace. "Each of the shell metal jacketsillustrated by jackets 19 andflZl offurnacefishell 18. Jackets 19 and 21are spaced from each other ing structure disposed between the jackets. Chamber 23 defined betweenthe'jackets may be filled with water or other coolant when it is desired to reduce-oro'ther- Wise control the temperature within the furnace as for instance when cooling the furnaceprior to removing a finished casting. ,In the case .of a titanium casting, since titanium is reactive withairat temperaturesmuch above 800 .C., the interiorsof the furnace usually .is

lowered below this temperature before ..introducing tair into the furnace.

'Furnace shells .16, 17, ,and 118 :are secured together in substantially a pressure-tight relationship hymeans of clamping members '24. .Clampingmemhers24;.grip .the outer faces of flanges 22 -and .25 carried by v the. furnace by suitable bractrode is consumed, theelectrode is lowered "nace by lowering stinger1'2 in shield 11.

stinger 12,- which carries ing the arc in the furnace, from sleeve ll' and the'body trical connection sets of flexible cables 42 are water cooled to increase projects upwardly from center Shielding clamping together flanges 27 and 28 :carri d by :the stack and the turret, respectively, with a set of clamping members '29. Referring to Fig. "2, a pressure-tight seal between thesemembers is obtained by clamping the flanges together about an O-ring in a manner similar to the assembly of the furnace shells.

Shielding sleeve 11 is relatively long, enabling the useof a relativelylong titaniumelectrode. As theelecinto the fur Secured to the top of-sleeve 11, as by clamps '31,is a stinger guide element 32. Stinger 'guide 32 includes a hub section 33, encompassing stinger -12 and vertically aligning the stinger'in 'stack'll, andaflangeSS. During melting under vacuum, clamps 31 may be removed, enabling element to *serve as an explosion blow-off cap. "Interposed"-between flange shielding sleeve 11 is an: annular 38 and a flange 39 of electric insulating ring insulates stinger guide 32 and the electric current for produc- 41. Insulating ring 41 of-the furnace. In'the-ernbodiment illustrated, the elecbetweenthestinger and one of'thepair of power supply'conductors in a plant is made bytwo extending from diametrically opposed portions of stinger 12. The cables ordinarily their current capacity. By

7 using two sets of cables, movement of the cables bepans'ible ffluid motor -45 .having cylinder 48. suitable support structure .cylinder functions to lower pulley .51 raise the, stinger within furnace. body 110.

and sealing ring generally at 61. 'Theladle is mounted to be cause of any magnetic field to'be nullified. Cables 42 are secured at one end to the power supply conductor, which may'take theform 0f abus bar (not shown),.-an'd at their other end to a "clamp member 431clampe'd about and tightly contacting the upper end of stinger 12.

Stinger 12 is raised and loweredwithin the furnace andthe ,shieldingsleeve or stack by any suitable means and cable '47. In the casting of .ti-

set up in the cables tends relatively soon after the are within the furnaceiscut ofi and I before. appreciable cooling of the molten metal takes place.

Mechanism is included forrapidly withdrawingthe titanium electro'defrom the interior of the .furnace so as,to raise "the lower end of the electrode freeof the vessel containingmolten metal and thusenable the vessel ,to be tilted without striking the lower end of the electrode. This mechanism includesanlen aflixed to and a wpiston49 carrying a pulley 51 .riding on a horizontal portion of cable 347. Retraction of piston .49esharplydownwardly within the so as to abruptly ."Referringto .Fig. 4, stinger .12 is .slidably mounted within. stinger-guide, 32.by:means ofa packing gland "52 f 53. This construction accommodates slidable movement of the stinger while maintaining substantially pressure-tight seal around the stinger.

As can -be':best -seen"in:Fig. 2, positionejdbelow the lower'end -of electrode 13 is "a ladle means :indicated tilted or canted to either side of anupri'ght position when apour is ma'clefromthe ladle. .Molten titanium 'ispouredfrom the ladle. into a "conventional ,mold indicated by ,dotte 1 17 With-the interior ofturret 2.6 in com .munication with .the interior of the furnace. sleeveor stack'llissecuredwto the top of turret .26 by lines at 62 supported on a table 63 within the furnace chamber.

Ladle 61 is supported within the interior of the furnace chamber by a pair of tubular shaft sections or canting arms 64 and 66 axially aligned with one another and mounted for rotation about their longitudinal axes relative to the side walls of furnace shell 17. The shaft sections are made of electrically conductive material, such as copper, the shaft sections together with ladle 61 forming part of the circuit for the production of the electric arc in the furnace. The shaft sections are nonrotatably affixed at their inner ends to ladle 61, and the outer ends of the shafts project outside of furnace body 10. The ladle is tilted by rotating the shafts from a point outside the furnace, the shaft sections thereby functioning as a motion transmitting mechanism for canting the ladle within the furnace. Cooling water for the ladle is introduced into the interior of the shaft sections from an inlet point located outside the furnace. By the construction employed, the use within the furnace of flexible conductors, flexible hose connections, swivel connections, or motor mechanism for tilting the ladle may be done away with.

More specifically, ladle 61 comprises an inner container portion 67 and an outer jacket portion 68 spaced from each other to present thereinbetween a cavity 69. Inner container portion 67 and jacket portion 68 are comprised of copper, save for a lower portion 70which is comprised of steel and welded at 65 to the ladle. Ladle 61 provides a path for the current producing the arc in the furnace. Container portion 67 has walls which incline inwardly from the top of the container and a rounded bottom enabling the easy removal of the solidified skull of titanium which normally forms on the surface of the containerportion during the melting operation. Such a skull forms by reason of the fact that the walls of the container are cooled below the melting point of titanium to prevent the copper portions of the ladle from melting. The rounded bottom of container portion 67 more or less conforms to thecurvature of the skull which forms, thereby reducing the build-up of large deposits of solidified titanium in the skull.

To either side of packet portion 68 are a pair of copper tubular stub sections 71 and 72 which are connected at their outer ends to the inner ends of tubular shaft sections 64 and 66. With reference to Fig. 2, a conduit 73 connects intermediate portions of stub section 72 to the bottom of outer jacket 70. A wall 74 extends across the inner end of stub section 72 so that coolant introduced through the interior of shaft section 66 is deflected by wall 74 downwardly through conduit 73 into cavity 69. A baflie 76 directs the coolant upwardly and out of cavity 69, the coolant flowing around baflle 76 through stub section 71 and out of the furnace through shaft sec-, tion 64.

Shaft sections 64, 66 are connected to stub sections 71, 72 by the detachable connection best illustrated in Fig. 3. Referring to Fig. 3, each of the shaft sections carries at its inner end a flange 77, and each of the stub sections carries at its outer end a flange 78. These flanges are bolted together by bolts 79 in tight electrical contact with each other. Clamping rings 81 and 82, comprised of steel or some other such material, are included to insure adequate electrical contact between the relatively soft copper flanges. The interiors of the stub and shaft sections carry coolant for ladle 61 so a waterseal is included between the flanges. A groove 83 extending about the circumference of. flange 77 seats on an O-ring 84 which is compressed between the flanges when the flanges are juxtapositioned. Groove 83 is roughly two-thirds the depth of the O-ring so that the O-ring is resiliently deformed as shown in Fig. 3 when the flanges are pressed together. 1

I The inner ends of shaft sections 64 and 66 are rotatably supported within the furnace in hangerjbrackets 86, 87. Intermediate portions of the shaft sectionsare supported in the walls of the furnace in sleeve segments 88 and 89 aflixed to furnace body 10. A substantially pressure-tight seal is created between the shaft sections and sleeve segments by means of packing glands 91,' 92 and suitable packing material surrounding the shaft sections and compressed against the shaft sections by the packing glands.

A swivel joint, such as swivel joint 95, connects the outer end of each shaft section to suitable conduits supplying and discharging cooling "water to ladle 61. The swivel joint permits rotation of the shaft sections relative to the water supply and exhaust conduits and are conventional in construction. 6 j

Aflixed to each of the shaft sections inwardly from the swivel joints, and outside the furnace walls, are a pair of conductor clamps 99 and 100, respectively. Each clamp surrounds a shaft section and has a pair of ends which are pulled together by bolts 101. Flexible CQII'. ductors 102 connect each conductor clamp to the other of the pair of power supply conductors in a plant. The electric circuit for producing an arc in the furnace comprises, therefore, conductor 42 connected to one of the power supply conductors, stinger 12, electrode 13, ladle 61, shaft sections 64 and 66, and conductors 102 which are connected to the other of the supply conductors. By using diametrically opposed conductor connections to ladle 61, represented by shaft sections 64, 66, the are produced in the furnace tends to be centered in the ladle.

Referring again to Fig. l and Fig. 2, a sprocket 103 aflixed to shaft section 64 and a drive chain 104 provide a means for rotating the shaft segments about theirlongitudinal axes to either side of a base position for the shaft segments, ladle 61 carried by the inner ends of the shaft segments occupying an upright position when the shaft sections are in their base position. A motor 106 and a sprocket power the drive chain and sprocket 103.

Projecting inwardly from a plate 111 secured to rotate with sprocket 103 is a finger 112. In the path of finger 112 as it rotates with shaft section 64 are three switches, a basing switch 113 and a pair of limit switches 114, 115, spaced below switch 113. Limit switch 115 is obscured in Fig. 2. The basing switch operates to automatically turn off the power supply for electric motor 106 for a certain time interval when shaft section 64 is rotated into its base position from a position to either side of the base position. The two limit switches shut off the power supply for motor 106 when shaft 64 is rotated to either one of a pair of limit positions located to either side, respectively, of the base position for the shaft. The limit switches stop the tilting of the ladle at predetermined optimum pouring positions.

Referring to Fig. 6, wherein the control system for motor 106 is set forth schematically, powerfor motor 106 is delivered through a pair of conductors 121, 122. The motor is conventional, rotating counterclockwise in Fig. 6 when a switch 123 is closed and rotating clockwise in Fig. 6 when a switch 124 is closed. A pair of conductors 126, 127 supply the current controlling the operation of switches 123, 124.

Switch 113 connected to conductor 126 has a pair of switch contacts 128 and 129. Switch contact 129 is connected through a thermal element 131 to conductor 127, thermal element 131 closing a switch 132 after a predetermined time delay.

Connected by a conductor 135 to switch 132 are a pair of push button switches 133 and 134, respectively. When shaft 64 occupies its base position, switch point 137 of switch 113 engages switch contact 129 and thermal element 131 is energized. After the expiration of a time delay, switch 132 is closed and motor 106 may be driven either in a clockwise or counterclockwise direction by closing one of the pair of switches 133, 134. If switch 133 is closed, current flows through conductor 135, the solenoid ganged to switch 123, switch 114,-and

conductor .127, so that-switch .123 closes and rotation of motorrl06iis ina counterclockwise direction. .If switch .13:4.is-closed, currentflows .throughconductor 135, the solenoid gangedtoswitch 124, .switch 113,,and conductor 127, so that ,switch.124.closes and rotationof motor 106 is in acloc'kwise direction.

As long. as. either switch 133 .or 134 ,is .closed, rotation of the motor continues until finger 112 reaches one of the pair .of limit switches 114, 1.15. After :shaft64 is rotated away from its.base position, switch point .137 of switch 113-engages switch contact 128 which completes the circuit between .conductor .126 and conductor .135.

If shaft 64 is positioned to eithersideof-itsbase position and it is desired to return the shaft to.its basetposition,.return rotation ofthe shaftisbrought about by .closing.the;appropr iate oneof the ,pairof pushibutton switches 51.3 134. For: instance, if the shaft-should be rotated ina clockwise direction in order to return the shaft .to .its base position, :closing push button switch -1-34-brings about the desired rotation. Rotation of the shaft continuesin a c'lockwise.direction until the shaft reaches its base positionat 'Whicht-ime switch point 137 engages switch contact --129 of switch 113, thetsolenoid ganged to switch 124 isde-energizejd, and-switch v124 opens. ,If push button switch 1-34remains closed, rotationnf-shaft 64 continues afterswitch ;'132;is ,elosed by. thermal element. 131. The time delay in the. circuit enables an operatoraccurately "to ,:position shaft 64 in its .base position while :permitting the operator ,to 1 make pours toeither sideof the;base p,osition if desired.

pair ofswitches v138 and 139 connected-between conductor 135 and the solenoids controlling operation of switches 12-3, 124 .are included to provide a means for qremotelycontrolling :the operation of motor 106. These switches customarily wouldlbe located some distance awayfrom push button switches :133, :1-34.

Included -in' the furnace, aresa; pressure gauge '141 1 (Fig. :2.) and ;a conduit 142 for introducingan inert. gasinto thefurnace when it is desiredto reduce'the temperature within the furnace. .An exhausttconduitj-143 (Fig. 1) connected to asuitable vacuum generator (not shown) is :also :provided for evacuating the atmosphere from withinzthe furnace. A fanmay also be.included within the furnace to increase the coolingrate within the .furnace.

*Whiletherehasbeen. described anembodiment of this invention, itzis not intendedto belimited thereby, audit is;desired.to;.cover all modifications which .would be apparent :toztone skilled in the art and that come within theseope of the appended claims.

. Ittisgclaimed and desiredtorsecureiby Letters Patent:

1. An electric arc furnace for the production of metal castings comprising ;a furnace bodyx-having walls defining ancwenclosed furnacezchambena pair ofe'lectrodes .Within :the interior of :the furnace :for producing an arc therein, :one .'Of thelatter. taking. the form of ladle means, flndicantingtmeans for-tilting: said ladle means, said canting[;m.eans comprisinga cantingarm extending through azwall :of saidfurnace :body and mounted for rotation relative thereto, an inner portion of.-said. arm-being se- Cured to; and in. electrical contact with said ladle means and antoutereportionofvzsaidarm projecting outside of said furnace ,chamber, 1 said. canting warm :having a .conductor portion :providing an electrical path between said inner and outer portions of said arm,-said conductor:por. tionconstitutingapart of:.theelectrical .circuitifor the plioductioniofan electric arc in,said.-furnace,:rotation of said'routerzportionof said canting :arrn-tilting .saidladle 1168118.

.2. :Afurnacerfor .the-..pro;duction. of. metal castings. comprising a furnace ;body vhaving walls defining an :enclosed furnace rchamber,.a pairof'electrodes within the .interior of L'the, furnace for producing an are therein, one

pfrthe glatter rtaking the :form of ladle-:means, -said ladle ihaving .tcirculating :passage ,means :circuiating -a coolant for saidladlemeans, and canting means for tilting said ladle means, said canting means comprising .a canting arm extending through a wall of said furnace and mounted for rotation relative thereto, an inner portion of said arm being secured toand in electrical contact with said ladle means and an outer portion ofsaid arm'projecting outside ofvsaid furnace chamber, and fluid transfer passage means influid communication with said circulating passage means andextending Within said canting arm between said circulatingpassage means and said outer portion of said arm, said canting arm having a conductor portion providing an electrical path between said innerand outer portions of said arm, saidconductor portion constituting a part of the electrical circuit for the productionofan electric arm in said furnace, .rotation of said outer portion of said canting arm tilting said ladle means. 7

3. An electric arc furnace for the-production ofmetal castings comprising .a furnace body having walls defining an enclosed furnace chamber, a pair ofelectrodes within the interior of the furnace for,producing .anarc therein, one of the latter taking the form of ladlemeans, said ladle means having circulating passage meanstcirculating acoolant for said ladle means, and canting means fortilting said ladle means, saidlastcantingmeans comprising a canting arm comprised of electro-conductive material rotatably mounted in and extending through a wall of said furnace body, an,inner portion of said arm being secured to and in electrical contact with said ladle means .and an outer portion of said arm extending outside of said furnace chamber, fluid transfer passage means in fluid communication .with said circulating passage means and extending within said canting arm between .said circulating passage means and said outer portion of said arm, and electrical conductor means connected to said outer portion of said canting arm, said canting-arm andconductor means,constitutingapart of the electrical .circuit.for the.production ofan electric arc in said furnace, rotation of said outer portion of said canting arm tilting said ladle-means.

4. .Theelectricarc furnace of claim 3 which "further comprises power driven actuating means connected to said outer portion ofsaid canting arm operable to.-rotate said canting arm so as to tilt said ladle means, and means limiting rotation of said canting arm by said actuating means beyond a pair of limit positionslocatedto either side of a base position for said arm, respectively, said canting arm in said base position supportingsaid ladle, means in an upright position within said chamber.

5. A casting furnace for theproductionof metalcastings'comprising afurnacebody having walls defining an enclosed furnace chamber, ladle means within the in terior of said furnace chamber, said ladle means having circulating passage means circulating acoolantrfor said ladle means, and canting means for tilting said ladle means, .aid canting means comprising a canting armextending through a wall of said furnace. body and mounted for rotation relative thereto, an inner portion of said arm being secured to said ladle means and an outerportion of said arm projecting. outside of said-furnace chamber, fluid transfer passage means infiuid communication with said circulating passage means and extending'within said canting arm between said circulating passage means and said outer portion of. said-arm, power driven actuating means connected to said outer portion of said arm operable to rotate said canting arm .so.;as to. tilt said ladle'means, and means limitingrotation ofsaid canting armby. said actuating means beyond a pairof limit positions located to either side of a, base positionfor said arm, respectively,said canting arm in said baseposition supporting said ladle means in an upright position within said furnace chamber.

6. The casting furnace of claim 5 which further includes means for positioning said canting arm insaid base position. T

7. In an electric arc casting furnace having furnace wall portions defining an enclosed furnace chamber and ladle means disposed within the interior of said chamher, said ladle means having circulating passage means circulating a coolant for said ladle means, canting means for tilting said ladle means and enabling a pour to be made from said ladle means, said canting means comprising a pair of axially aligned tubular shaft sections nonrotatably affixed at their inner ends to opposite sides of said ladle means, respectively, outer end portions of said shaft sections projecting outside of said furnace chamber, the interior of each of said tubular shaft sections connecting with said circulating passage means and providing a fluid transfer passage for coolant circulated in said ladle means, rotation of said outer end portions of said shaft sections tilting said ladle means.

8. In an electric arc casting furnace having furnace wall portions defining an enclosed furnace chamber, a pair of electrodes within the interior of the furnace for producing an arc therein, one of the latter taking the form of ladle means, the improvement comprising canting means for tilting said ladle means and enabling a pour to be made from said ladle means, said canting means comprising a pair of axially aligned shaft sections nonrotatably affixed at their inner ends to opposite sides of said ladle means, respectively, outer end portions of said shaft sections projecting outside of said furnace chamber, at least one of said shaft sections being comprised of electro-conductive material, and electrical conductor means connected to the outer end portion of said one of said shaft sections, said one of said shaft sections and said conductor means constituting a part of the electrical circuit for the production of an electric arc in said furnace, rotation of said outer end portions of said shaft sections tilting said ladle means.

9. In an electric arc casting furnace having furnace wall portions defining an enclosed furnace chamber, a pair of electrodes within the interior of the furnace for producing an arc therein, one of the latter taking the form of ladle means, said ladle means having circulating passage means circulating a coolant for said ladle means, the improvement comprising canting means for tilting said ladle means and enabling a pour to be made from said ladle means, said canting means comprising a pair of axially aligned tubular shaft sections nonrotatably affixed at their inner ends to opposite sides of said ladle means, respectively, outer end portions vof said shaft sections projecting outside of said furnace chamber, the interior of each of said tubular shaft sections connecting with said circulating passage means and providing a transfer passage means in said ladle means, at least one of said shaft sections being comprised of electro-conductive material, and electrical conductor means connected to the outer end portion of said one of said shaft sections, said one of said shaft sections and said conductor means constituting a part of the electrical circuit for the production of an electric arc in said furnace.

10. The apparatus of claim 9 wherein each of said tubular shaft sections is affixed to said ladle means by means of a detachable connection.

11. The apparatus of claim 10 wherein said detachable connection comprises co-operating annular flange portions presented by the shaft section and said ladle means, respectively, oppositely disposed faces of said flanges abutting each other to provide electrical contact, one of said flange portions having an annular groove therein accommodating an annular sealing member disposed between said flange portions, said annular sealing member being resiliently deformed by juxtapositioning said flange portions.

for coolant circulated.

12. An electric arc casting furnace comprising a set of furnace shell sections secured together in substantially pressure-tight relationship and defining within said shell sections an enclosed furnace chamber, means for producing a vacuum within said chamber, apair of electrodes within the interior of the furnace chamber for producing an arc therein, one of the latter taking the form of ladle means, said ladle means having circulating passage means circulating a coolant for said ladle means, and canting means for tilting said ladle means while maintaining said chamber under vacuum, said canting means comprising a pair of axially aligned tubular shaft sections nonrotatably affixed at their inner ends to opposite sides of said ladle means, respectively, outer end portions of said shaft sections projecting outside of said furnace chamber, the interior of each of said tubular shaft sections connecting with said circulating passage means and providing a transfer passage means for coolant circulated in said ladle means, at least one of said shaft sections being comprised of electro-conductive material, and electrical conductor means connected to the outer end portion of said one of said shaft sections, said one of said shaft sections and said conductor means constituting a part of the electrical circuit for the production of an electric arc in said furnace.

13. An electric arc casting furnace comprising a set of furnace shell sections secured together in substantially pressure-tight relationship and defining within said shell sections an enclosed furnace chamber, means for producing a vacuum within said chamber, a pair of electrodes within the interior of the furnace chamber for producing an arc therein, one of the latter taking the form of ladle means, said ladle means having circulating passage means circulating a coolant for said ladle means, and canting means for tilting said ladle means While maintaining said chamber under vacuum, said canting means comprising a pair of axially aligned tubular shaft sections nonrotatably aflixed at their inner ends to diametrically opposed sides of said ladle means, respectively, said inner ends of said shaft sections being in tight electrical contact with said ladle means, outer end portions of said shaft sections projecting outside of said furnace chamber, means for rotating said outer end portions of said shaft sections, the interior of each of said shaft sections connecting with said circulating passage means and providing a transfer passage means for coolant circulated in said ladle means, each of said shaft sec tions being comprised of electro-conductive material, and electrical conductor means connected to the outer end portions of each of said shaft sections, said ladle means, shaft sections, and conductor means constituting a part of the electrical circuit for the production of an electric arc in said furnace, said shaft sections providing diametrica'lly opposed branches in said electrical circuit operable to center the arc in said furnace.

References Cited in the file of this patent UNITED STATES PATENTS 1,472,286 Townsend Oct. 30, 1923 1,848,249 Goldberg Mar. 8, 1932 2,528,571 Babcock et al. Nov. 7, 1950 2,675,414 Capita Apr. 13, 1954 2,726,278 Southern Dec. 6, 1955 2,752,409 Eaton June 26, 1956 2,800,519 Garmy July 23, 1957 2,845,293 Peckham July 29, 1958 FOREIGN PATENTS 129,779 Germany Apr. 17, 1902

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