CA1128281A - Electromagnetic casting method and apparatus - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A method and apparatus for electromagnetic continuous or semicontinous casting of metals and alloys. In one embodiment a variable coolant application system is used to control the rate of heat extraction from the casting to properly position the solidification front at the surface of the casting without otherwise influencing the ?
process through modification of the magnetic field. Prefer-ably both embodiments are combined.

Description

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This application is a division of ~pplication Ser. No. 323,493, filed March 15, 1979.
BACKGROUND OF T~IE INVE TION
This invention relates to,an impr~ved process and apparatus for electromagnetically casting metals and alloys particularly heavy metals and alloys such as copper and copper alloysO The electromagnetic casting process has been known and used for many years for continuously and semi-continuously casting metals and alloys, The process has been employed commercially for casting aluminum and aluminum alloys.
PRIOR ART STATEMENT
The electromagnetic casting apparatus comprises a three part mold consisting of a water cooled inductor, a non-magnetic screen and a manifold for applying cooling water to the ingotO Such an apparatus is exemplified in U.S. Patent ~o. 3,467,166 ~o Getselev et al. Containment of the molten metal is achieved without direct contàct between the molten metal and any component of the mold.
Solidification of the molten metal is achieved by direct - applica-tion of water from the cooling manifold to the ingot shell.
The cooling manifold may direct the water against the ingot from above, from within or from below the inductor as exemplified in U. SO Patent Nos. 3,735,799 to Karlson and 3,646,988 to Getselev, In some prior art approaches the inductor is formed as part of the cooling mani~old so that the cooling manifold supplies both coolin~ to solidify the casting and to cool the inductor as exemplified in U.S.
Patent Nos. 3,773,101 to Getselev and 4,004,631 to Goodrich et al.

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The non-magnetic screen is utilized to properl~ shape the magnetic field for containing the molten metal as exemplified in U.S. Patent No. 3,605,865 to Getselev. A
variet~ of approaches with respect to non-magneki¢ screens are exemplified as well in the Karlson '799 patent, and ln U.S. Patent No. 3~985,179 to Goodrich et al. Goodrich et al.
'179 describes the use of a shaped inductor to shape the field. Similarly, a variety of inductor designs are set forth in the aforenoted patents and in U.S. Patent No.

3,741~280 to Kozheurov et al.
While the above described patents describe electro-( magnetic casting molds for casting a single strand or ingot at a time the process can be applied to the casting of more than one strand or ingot simultaneously as exemplified in U.S. Patent No. 3,702,155. In addition to the aforenoted patents a further description of the electromagnetic casting process can befound by reference to the following articles:
"Continuous Casting with Formation of Ingot by Electro-magnetic Field", by P.P. Mochalov and Z.N. Getselev, Tsvetnye I~Iet., August, 1970, ~.3, pp. 62-63; "Formation of Ingot Surface During Continuous Casting", by G.A. Balakhontsev et al., Tsvetnye Met.~ August, 1970, 43, pp. 64-65; "Casting in an Electromagnetic Field!', by Z.N. Getselev, J. Of Metals, October, 1971, pp. 38-59; and "Alusuisse Experience with Electromagnetic Moulds", by H.A. Meier, G.B. Leconte and A.
M. Odok, Light Metals, 1977, pp. 223-233.
In U.S. Patent No. 4,014,379 to Getselev a control system is descr-bed for controlling the current flowing through the inductor responsive to deviaticns in the dimen-sions of the liauid zone (molten metal head~ of the ingot from a prescribed value.

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The invention herein is particularly concerned with the apparatus for applying cooling water to the ingot for solidification. It is known for electromagnetic casting that the solidification front be~ween the molten metal and the solidifying ingot at the ingot surface should be maintained within the zone of high magnetic field strength. Namely, the solidification front should be located within the inductor.
If the solidification front extends above the inductor, cold folding is likely to occur. On the other hand, if it recedes to below the inductor, a bleed out or decantation of the liquid metal is likely to result.
It is known in the art of Direct Chill casting in a water cooled mold to utilize a coolant application arrange-ment wherein the cooling water applied to the mold and ingot is periodically interrupted or pulsed on a cyclic basis. By varying the ratio of water "on" to water "off" time, good control over the rate at which the coolant removes heat from the ingot can be achieved. This pulse cooling process is amply illustrated by reference to U.S. Patent No. 3,441,079 ;20 to Bryson and to an article entitled"Direct Chill Casting Process for Aluminum Ingots - A Ne~ Cooling Technique", by N.B. Bryson, Canadian Metallurgical Quarterly, Vol. 7, No.l, Pages 55-59.
In Getselev et al. t 166 the coolant application manifold is assciated with the screen pcrtion of the mold and they are arranged for simultaneous movement relative to the ~; inductor. This is not a suita~le system for adjusting the water application plane since movement of the coolant manifold entails corresponding movement of the screen which results 3 in undesira~le modification in the field shape of the mold ~z~

and hence, in the resulting ingot shape. In Getselev '988 there is disclosed a moveable manifold mounted below the inductor. This system would appear adequate for hiyh con-ductivity alloys especially where low castiny speeds are used. However, the apparatus described provides a minimurn separation between the plane of water application and the inductor mid plane comprising one-half the height of the inductor. If this apparatus were applied to copper alloys of moderate or fairly low conductivity, then in order to properly position the plane of coolant application, it would be necessary to use an impractically short inductor height unless restrictively low casting speeds were employed.

SUMMARY OF THE INVENTION
In accordance with an alternative method and apparatus of this invention the above-noted deficiencies are overcome by providing a water cooling means that may be adjustably positioned to control the solidification front at the surface of the ingot without otherwise influencing the containment process through modification of the magnetic field. The water cooling means of this invention is arranged to direct the water stream onto the surface of the ingot from a manifold situated essentially above the inductor and which extends between the inductor and the non-magnetic screen. The manifold is capable of movement in a direction axially of the casting to adjust the location of the plane o~ water impact.
In accordance with a particular embodiment of the invention there is provided in an apparatus for continuously or semicontinuously casting metalso means for electro-magnetically containing molten metal and for forming saidmolten metal into a desired casting, said electromagnetically z~

containing and forming means including: an inductor for applying a magnetic field to said molten metal, and a non-magnetic screen means for shaping said magnetic field, said screen means being arranged coaxially with said inductor, said apparatus further including means for apply-ing coolant to said casting for solidifying said molten metal, said coolant applying means including a manifold and at least one coolant discharge port connected to said manifold for directing said coolant against said casting;
said inductor and said coolant applying means being coaxially arranged about an axis o said casting w~ich defines a desired axial direction, the improvement wherein, said apparatus further includes: means for controlling the position of a solidification front in said axial direction at a surface of said castLng, said.means for controlling said position of sald solidification front comprising means for adjustably supporting said at least one coolant dis-charge port for movement in said axial direction between said inductor and said non-magnetic screen means independ-ently of said electromagnetically containing and forming : means' whereby the position at which the coolant is applied to said surface of said casting can be adjusted to control the position of said solidification front without modifying said magnetic field ~: From a different aspect, and in accordance with the invention, there is provided, in a method for contin-uously and semicontinuously casting metals, the steps comprising: electromagnetically containing and forming ~` molten metal into a desired casting, said electromagnetically containing and forming step including the steps of:

providing an inductor for applying a magnetic field to .

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molten metal and providing a non-magnetic screen for shap-ing said magnetic field; and applying said magnetic field to said molten metal; said method further comprising:
applying coolant to said casting for solidifying said mol~en metal, said coolant applying step including the step of providing a coolant discharge port for directing said coolant against said casting; and controlling the position of a solidification front at a surface of said casting, said controlLing step including the step of adjusting the position of said coolant discharge port without substan-tially modifying said magnetic field by moving said dis-charge port between said non-magnetic screen and said inductor and independently thereof.
Accordingly, it is an ob]ect of this invention to provide an improved method and apparatus for the electro-magnetic casting of metals and alloys~
It is a further object of this invention to pro-vide an improved method and apparatus as above for control-ling the position of the solidification front.
These and other objects will become more apparent from the following description and drawings.
BRIEF DESCRIPTION OF THE DRA~INGS
Figure 1 is a schematic representation of an electromagnetic casting apparatus in accordance with one embodiment of this invention; and Figure 2 is a schematic representation of an electromagnetic casting apparatus in accordance with a different em~odiment of this inv~ntion - ~a -i~2~ZI~

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to Figure 1 there is shown by way of example an electromagnetic casting appara-tus in accord-ance with one embodiment of this invention, The electromagnetic casting mold 10 is comprised of an inductor 11 which is water cooled; a coolant manifold 12 in accordance with this invention for applying cooling water to the peripheral surface 13 of the metal being cast C, and a non-magnetic screen 14. Molten metal is continuously .
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introduced into the mold lO during a casting run, in the normal manner using a trough 15 and down spout 16 and conventional molten metal head control. The inductor ll ls excited by an alterna'cing currenk from a suitable pow~r source ~not shown).
The alternating current in ~he inducotr ll produces a magnetic field whlch interacts with the molten metal head l~
to produce eddy currents therein. These eddy currents in turn interact with the magnetic field and produce forces which apply a magnetic pressure to the molten metal head 19 to contain it so that it solidifies in a desired ingot cross , section.
An air gap exis's during casting, between the molten metal head l9 and the inductor ll. The molten metal head l9 is formed or molded into the same general shape as the inductor ll thereby providing the desired ingot cross section.
The inductor may have any desired shape including circular or rectangular as required to obtain the desired ingot C
cross section.
The purpose of the non-magnetic screen 14 is to fine tune and balance the magnetic pressure with the hydrostatic pressure of the molten metal head 19. The non-magnetic screer.
14 can comprise a separate element as shown, or it may comprise a part of the manifold 12 for applying the coolant as desired.
Initially, a conventional ram 21 and bottom block 22 is held in the magnetic containment zone of the mold lO to allow the molten metal to be poured into the mold at the start of the casting run. The ram 21 and bottom block 22 are then uniformly withdrawn at a desired casting rate.

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Solidification o~ the molten metal which is magneticall~
contained in the mold 10 is achieved by direct application of water from the cooling manifold 12 to the ingot sur~ace 13. In the embodiment which is shown in Figure 1 the ~rate~
is applied to the ingot surface 13 within the confines of the inductor 11. The water may be applied to the ingot surface 13 ~rom above, within or below the inductor 11 as desired.
The solidification front 25 of the cast~ng comprises the boundary between the molten metal head 19 and the solidified ingot C. It is most desirable to maintain the ( solidification front 25 at the surface 13 of the ingot C at or -close to the plane of maximum magnetic flux density which usually comprises the plane passing through the electrical centerline 26 of the inductor 11. In this way, the maximum magnetic pressure opposes the maximum hydrostatic pressure of the molten metal head 19. This results in the most efficient - use of power and reduces the possibility of cold folds or bleed outs.
The location of the solidification front 25 at the ingot surface 13 results from a balance of the heat input from the superheated liquid metal 19 and the resistance heating from the induced currents in the ingot surface layer, with the longitudinal heat extraction resulting from the coollng water application. The location of the front 25 can be characterized ~rith regerence to its height "d" above the location of the coolant applicat~on plane 27. Hence~ the plane o~ coolant water appllcation 27 can be referenced to the electrical centerl~`ne 26 o~ the inductor. That distance 3 "d" depends on a multiplicity of factors. "d" decreases with 9036-~B
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increasing: latent heat of solidification of the alloy being cast; specific heat of the alloy; electrical resistivi~y of the alloy; molten metal head height; inductor heigh~; melt superheat; lnduc~or current amplitude; indu¢'cor cu~ren~
~requency; casting speed; and with decreasing alloy conductivity and visa versa.
For a given alloy, the physical properties, latent heat of solidification, specific heat, thermal conductivity, and electrical resistivity are more or less fixed. Normal ; 10 electromagnetic casting practice would fix the inductor 11 current frequency within limits, the geometrical arrangement of the inductor 11 and its height, the molten metal head 19 height and ~he inductor 11 current amplitude. It follows, therefore, that the onl~ remaining major process control - variable affecting the position of the solidification front 25 at the surface 13 of the ingot C is the casting speed.
There~ore, it would be necessary to adjust the casting speed in order to adjust the position of the solidification front 25 to the favorable location corresponding to the plane - ( l20 through the centerline 26 of the inductor 11. However, in practice other factors such as cracking and formation of undesirably coarse microstructures limit the range of casting speeds which can be used.
In accordance with this invention the problem of maintaining the solidification front at its desired position is overcome by controlling the ra~e at which heat is extracted from the solidifying ingot and/or by ad~usting the plane of water application with respect to the inductor. These techniques allow adjustment of the position of the solidifi-cation front 25 location independent of casting speed and alloy properties.

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In the embodiment of Figure 1 a solenoid valve 30 has been inserted in the inlet pipe 31 to the coolant application manifold 12. The solenoid valve 30 is connected to an ad~ustable timer 32 which actuates it interm~t~entl~. ~he timer 32 and solenoid valve 30 arrangement rnay be similar to that as described in the Bryson patent and article set forth in the background of the application. The timer 32 and solenoid valve 30 allow discontinuous application of the coolant to the ingot surface 13 which provides intermittent high and reduced levels of heat transfer leading to an over-all reduction in the average rate of heat removal from the solidifying ingot C as compared to a continuous flow. This has the effect of retarding the onset of solidification as compared to the continuous application of coolant and thereby lowers the position of the solidification front 25. Any changes in the flow rate of continuity of water àpplication affect the position of the solidification front 25 without -influencing the electromagnetic field.
In the apparatus 10 of this invention the coolant is applied directly to the ingot C surface 13 and the ingot never comes in contact with the inductor 11 or coolant application manifold 12~ Therefore, by controlling the duratic of the periods of the coolant application pulses and the duration of the periods between coolant application pulses one can e~fectively regulate the rate of heat extraction from the solidifying ingot.
The ti~er 32 comprises an adjustable timer of conven-tional design which is ærranged to actuate via wires 33 the electrically opera~ed solenoid ~al-~e 30 in the input cGnduit 31 to the coolant application manifold 12. The timer _9_ 27~

sequentially and repetltivel~ controls the period the valve 30 is open and the period between valve openings when lt is closed, to provide intermittent operation of khe valve so as to cause the coolant applied to the ingo~ surfa~e 13 ~o be pulsed. The respective periods when the valve is open or closed may be set as desired ko obtain the desired rate o~
heat extraction which will properly position the solidification front 25 in the solidifying ingot C.
Alternatively, if desired, instead of using an on/off valving arrangement 30 as described by reference to the ; embodiment of Figure l one could employ an arrangement wherein the pulsed ~low of the coolant is provided by intermittently applying two different levels of coolanc flow.
Referring to Figure 2 this can be readily accomplished through ~` the use of a servo-controlled valve 40 in the input conduit 41 of the manifold 42 and a conventional servo-amplifier and controller 43 for adjustably controlling the actuation of the valve 40 over its range of actuakion between its fully open and fully closed positions. Normally such control for pulse cooling operations would be between valve positions intermediate the fully open and fully closed positions. The servo-amplifier and controller 43 actuate the servo-controlled valve 40 to provide a pulsed output between two different le~els of coolant flow~ The valve 40 is adapted to rapidly change between iks respective high and low coolant flow positions. The respective periods o~ high and low flow may be set as desired by adjustment of the servo-amplifier 43 to provide the desired heak transfer rate to properly position the solidification front 25.

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Therefore, in accordance with this invention means are provided for controlling the position of the solidification front Z5 during the electromagnetic casting which comprise adjusting the coolant application means 12 or 42 to provide increased or reduced rates of heat e~trac~ion from the in~ot C in order to raise or lower the axial position, respecti~ely, of the solidification front. This is accomplished by any of a number of means including the intermittent pulsed appli-cation of the coolant or by intermittently changing the flow rate of the cool~nt in a pulsed manner.

The ac~ual adjustment o~ the respective periods of on/off ~ ~ operation of the valve 30 or of the periods of high and low - flow of the valve 40 usually occurs prior to a casting run.
However, if desired, the adjustment may occur during a casting - run to correct a mispositioning of the solidification front In the embodiment of Figure 2 it is also possible to utilize in conjunction with or in place of the solidification front 25 position control system 30 or 40 the first embodi-; 20 ment of this invention a solidification front position control system 50 in accordance with an alternative embodiment now to be described. The use of both systems in conjunction should provide a wider range of adjustment and increase the sensitivity of the adjustment.
In accordance with the alternative embodiment of the invention as shown in Figure 2 the coolant manifold 42 is arranged above the inductor and includes at least one dis-charge port 51 for directing the coolant against the surface - 13 of the ingot or casting ~ The discharge port 51 can 3 comprise a slot or a plurality of individual orifices for l~Z~

directing the coolant against the surface 13 of the ingot C about the entire peripher~ of that sur~ace~
In order to provide a means in addition or in place Or pulse cooling for controlling the solidification ~'ron~ 25 at the surface 13 of the ingot C without inf'luencing the containment of the molten metal through modification of the magnetic field~ the coolant manifold 42 with its dischar~e ; port 51 is ar:ranged for movement axially of the ingot C.
The coolant manifold 42, the inductor 11 and the non-magnetic screen 14 are all arranged coaxially about the longitudinal : axis 52 of the ingot C~ In the preferred embodiFient shown (~ i the coolant manifold 42 includes an extended portion 53 which includes the discharge port 51 at its free end. The extended portion 53 of the coolant manifold 42 is arranged for movement between the non-magnetic screen 14 and the : inductor 11 in the direction defined by the axis Or the ingot C.
The inductor 11 and the non-magnetic screen 14 are supported by conventional means known in the art (not shown).
{ `20 The coolant manifold 42 is supported for movement independ~
ently of the inductor 11 and the non-magnetic screen 14 so that the position of the discharge port 51 can be adjusted axially of the ingot without a concurrent movement of the non-magnetic screen 14 or the inductor 11. This is a sign-ficant departure lrom the approaches described in the prior art wherein the non-magnetic screen 14 is supported by the coolant manifold 12 and both are arranged for simul-taneous movement in the axial sense.

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By moving the discharge port 51 of the coolant manifold independently of the non-magne~ic screen 14 in accordance with this invention it is possible to ad~us~ the posi~lon the solidification fron~ 25 without modi~ying the rnagne~ic containment field. In the preferred embodiment sho~n in Figure 2 the discharge port 51 is arranged for axial movement ~etween the non-magnetic screen 14 and the inductor 11 along the path 62 as shown in phantom.
Another feature of this embodiment of the present inven~
tion is that the coolant manifold or at least that portion of the manifold which enters the magnetic field is formed ' of a material which will not modify the magnetic field.
Preferably, it is formed of a non-conductive material such as plastic or resinous materials including phenolics.
- In the embodiment shown in F~gure 2 the coolant manifold 42 includes three chambers 54~ 55 and 56. The coolant enters the manifold 42 in ~he first chamber 54. A slot or a plurality of orifices 57 arranged in the wall 58 between the first chamber 54 and the second chamber 55 serve to enhance ( ) the uniformity of the distribution of the coolant in the manifold 42. Similarly, slots or orifices 59 between the second 55 and the third chamber 56 further enhance the uniformity of distribution of the coolant in the manifold 42. The coolant is discharged from the axially extended third chamber 56 via the discharge port 51. The manifold 42 including the extended third chamber 56 is arranged for movement along vertically extending rails 60 so that the e~tended portion 53 of the manifold can be moved between the inductor ll and the screen 14 along the path 62 as shown in phantom.

Axial adjustment of the discharge port 51 position is provided by means of cranks 63 mounted to screws 64. The screws are rotatably secured to the manifold 42 at one end and are held in threaded engagement in support blocks 65 which are mounted to the rails 60. In this manner turnln~
the cranks 63 in one direction or the other will move the - manifold 42 and discharge port 51 axially up or down.
;- The coolant is discharged against the surface of the ' casting in the direction indicated by arrows 66 to define the plane of coolant application. By moving the discharge port 51 up or down in the manner described above the plane ( of coolant application 27 is also moved up or down respectively with respect to the centerline 26 of the inductor 11 to thereby change the distance "d".
Copper alloy ingots are typically cast in 6" x 30"
cross sections at speeds at from about 5 to 8" per minute.
Over this restricted speed range the preferred and most ; preferred water application zones ~cr three common copper alloys have been calculated as follows:
~ 20 TABLE I
- Calculated Water Cooling Application Zone Alloy Preferred Most P~eferred C 11000 - 1/2" ~ - 2" - 3/~ 2"
C 26000 ~ - 1 1/4" - 1/4" ) - 1"
C 51000 +3/8" ~ _ 3/4" + 1/8" t - 1/2"
The measurements provided in Table I are for the distance from the centerline of the inductor to the plane of the coolant application. The values are negative or positive, respectively~ depending on whether the plane of coolant ~pplication is arranged beloN or above the centerline of the

3 inductor.

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While it is most preferred in accordance with this embodiment of the invention to form the entire manifold 42 from a non-conductive material one could, i~ desired, forra only that portion of the manifold 42 whlch would lnteract with the magnetic field from the non-conductl~e material while using other materials such as mekals for the remaining portion of the manifold 42. For example, if desired, only the chamber need be formed from non-conductive material, whereas the chambers 54 and 55 could be formed from any desired material. The chamber 56 would then be ~oined to the chambers 54 and 55 in a conventional manner. Therefore, in accordance with this embodiment of the invention it is only necessary that the portion of the coolant application means which would interact with the magnetic field be formed from a non-conductive material.
The method of continuously or semicontinuously casting metals and alloys in accordance with this embodiment of the present invention involves the adjustment in an axial sense of the position of the manifold 42 and in particular, the discharge port 51 therein, prior to the beginning of a casting run in order to position the solidification ~r~nt 25 at an appropriate axial position lor the alloy being cast. It is preferred that this ad~ustment take place prior to the beginning of the casting run. However, if desired, the ad~ustment can be refined during a casting run. The discharge port 51 must be moved independently of the inductor 11 and screen 14 so that its change in position does not affect the magnetic field or the containment process~

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It should be apparent from the foregoing description ~ that as compared to cooling with a continuous full flow, pulse `~ cooling is only e~fective to lower the solidification fron~
25. However~ in accordance with this inven~ion when ope~a~ing . ~
in a pulse cooling mode within the ranges of the periods of coolant application or non-application or the periods of high or low flow it should be possible to raise or lower the - solidification front over a range of positions with the highest position comprising that corresponding to non-pulsed application of the coolant. The embodiment of the invention with respect to ~igure 2 is~ therefore~ particularl~ adapted , to increase the range of adjustment while using the pulsed coolant application. If it is necessary to raise the solidification front 25 above a maximum level achievable by adjustment of the pulsed cooling, this can be accomplished ;
by raising the position at which the coolant is applied to -~ - the ingot surface.
With respect to the embodiment of the invention wherein the pulsed coolant comprises periods of high and low coolant flow it is preferred that the lower flow rate be selected so that a steam film is generated which has the effect of markedly reducing the rate of heat transfer. This embodiment of the invention is particularly preferred because it should provide less abrupt changes in heat transfer at the ingot surface due to the steam film formation. In such a high/low pulsed flow mode heat transfer at the high flow periods is by nucleant boiling; whereas, in the low flow periods heat transfer is by film boiling. ~his provides marked differences in heat transfer between the pulses of high flow and low flow thereby allowing for the variation in the rate of heat 9036-~B
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extraction as described above in order to control the position of solidification ~ront 25.
The actual flow rates of the coolant in either of the pulsed cooling embodiments set forth above ~ay be set a~
desired. They will be a function of a number o~ variables including the alloy composition; the latent heat of the solidfication of the alloy being cast; the specific heat of the alloy; the melt superheat; the casting speed, etc.
The method and apparatus of this invention is particularly adapted to the continuous or semicontinuous casting of metals and alloys. Further details of the apparatus and method o~ electromagnetic casting can be gained from a considerationof the various patents and publications cited in this application, which are intended to be incorporated by reference herein.
While the invention has been described with reference to copper and copper base alloys it is believed that the apparatus and method described above can be applied to a wide range of metals and alloys including nickel and nickel alloys, ( 2~ steel and stèel alloys, aluminum and aluminum alloys, etc.
It is apparent that there has bee provided in accordance with this invention an electromagnetic casting apparatus and method which fully satisfies the ob~ects, means and advantages set ,orth herein before. While the invention has been described in combination with specific embodiments thereof, it is evident that many alternatives, modilications and variations will be apparent to those skilled in the art in light of the ~oregoing description.
Accordingly, it ls intended to embrace all such alternatives~
modi~ications and variations as fall within the sp~it and 3 broad scope of the appended claims.

Claims (11)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. In an apparatus for continuously or semicontinuously casting metals comprising:
means for electromagnetically containing molten metal and for forming said molten metal into a desired cast-ing, said electromagnetically containing and forming means including: an inductor for applying a magnetic field to said molten metal; and a non-magnetic screen means for shaping said magnetic field, said screen means being arranged coaxially with said inductor; said apparatus further including means for applying coolant to said casting for solidifying said molten metal, said coolant applying means including a manifold and at least one coolant discharge port connected to said manifold for directing said coolant against said casting; said inductor and said coolant apply-ing means being coaxially arranged about an axis of said casting which defines a desired axial direction; the improve-ment wherein, said apparatus further includes:
means for controlling the position of a solidifi-cation front in said axial direction at a surface of said casting, said means for controlling said position of said solidification front comprising means for adjustably sup-porting said at least one coolant discharge port for move-ment in said axial direction between said inductor and said non-magnetic screen means independently of said electro-magnetically containing and forming means; whereby the position at which the coolant is applied to said surface of said casting can be adjusted to control the position of said solidification front without modifying said magnetic field.

2. An apparatus as in claim 1 wherein at least a portion of said manifold which interacts with said magnetic field is formed of a material which will not substantially modify said field.

3. An apparatus as in claim 2 wherein said entire manifold is formed of said material.

4. An apparatus as in claim 2 wherein said material is substantially electrically non-conductive.

5. An apparatus as in claim 4 wherein said material comprises a plastic.

6, An apparatus as in claim 2 wherein said portion of said manifold includes said coolant discharge port.

7. An apparatus as in claim 1 wherein said manifold is arranged above said inductor and wherein said screen means is arranged coaxially with said coolant application means.

8. An apparatus as in claim 1 wherein said manifold includes an axially extended portion including said coolant discharge port and wherein said extended portion is arranged for said movement between said inductor and said non-magnetic screen means.

9. In a method for continuously and semicontinuously casting metals comprising:
electromagnetically containing and forming molten metal into a desired casting, said electromagnetically con-taining and forming step including the steps of:

providing an inductor for applying a magnetic field to molten metal and providing a non-magnetic screen for shaping said magnetic field; and applying said magnetic field to said molten metal; said method further comprising:
applying coolant to said casting for solidifying said molten metal, said coolant applying step including the step of providing a coolant discharge port for directing said coolant against said casting; and controlling the position of a solidification front at a surface of said casting, said controlling step including the step of adjusting the position of said coolant discharge port without substantially modifying said magnetic field by moving said discharge port between said non-magnetic screen and said inductor and independently thereof.

10. A method as in claim 9 wherein said inductor, said non-magnetic screen and said discharge port are coaxially arranged about an axis of said casting which defines an axial direction and wherein said discharge port is moved in said axial direction.

11. A method as in claim 10 including the step of forming said discharge port from a material which will not interact substantially with said magnetic field,