Patent Publication Number: US-6983007-B2

Title: Method of manufacturing electrodes and a reusable header for use therewith

Description:
BACKGROUND OF THE INVENTION 
   1. Technical Field 
   This invention generally relates to a method of manufacturing electrodes and more particularly to a method of manufacturing electrodes in a vacuum arc remelting furnace. Specifically, the invention relates to a method of manufacturing titanium electrodes, which method includes the use of a reusable header for supporting the electrodes to be melted within the furnace. 
   2. Background Information 
   There is a need in industry for high metallurgical quality metals such as titanium, titanium alloys and superalloys. These products are utilized in the production of turbines for aircraft and ships and in various other industrial applications. Often, high quality titanium metal and its alloys are produced by a process known as vacuum arc remelting. In this process, an electrode, made of titanium material, is melted by a direct current arc into a water-cooled crucible or hearth under a vacuum. The electrode may be formed from scrap materials, titanium sponge compacts and bulk scrap pieces that are melted together by electron beam or plasma arc melting or are conventionally welded together. The electrode is then welded to a header or stinger that is connected to a ram. The welding of the electrode to the header is both time consuming and labor intensive and therefore adds to the production costs for the process. Once the electrode is welded to the header, a ram lowers the electrode into the crucible or hearth where it is melted by a direct current arc struck between the surface of the electrode and the crucible. Molten droplets of metal fall from the electrode onto the bottom plate of the crucible thereby forming a molten ingot pool. As the arc is struck between the electrode and the ingot pool, the depth of the ingot pool increases. The crucible or hearth is water-cooled and consequently the molten ingot pool gradually cools down and solidifies into an ingot. As the depth of the solidifying ingot increases, the ingot may either be slowly withdrawn from the crucible or will tend to gradually fill up the crucible. The process continues until the electrode is substantially consumed and an ingot of higher metallurgical quality has been formed. The newly formed ingot may be as long as 300 inches. The ingot is allowed removed from the crucible and is allowed to cool over a number of days. If a higher grade metal is required, the newly formed ingot is again welded to a header so that it may be used as a second electrode. The need to wait until the ingot has cooled and then to weld the second electrode to the header again adds to the production costs. The second electrode is remelted using the same process and a second ingot of still greater quality is produced. This cycle of forming an ingot, welding the ingot to the header so that it may be used as an electrode, and melting the electrode to form a new ingot of improved metallurgical quality is repeated until the desired metallurgical qualities are produced in the final ingot. 
   During production, the forming ingot may be contaminated by accidental arcing of the header. As the electrode is consumed, it is reduced in length. If, however, the length of the titanium electrode is reduced too much, accidental arcing of the header may cause some of the material from the header to melt and drop into the ingot pool. This tends to contaminate the titanium metal in the ingot pool and additionally causes damage to the header. In order to overcome this problem, it has been customary to stop the direct arcing of the electrode some distance from the weld between the header and the electrode. While this tends to resolve the problem of accidental contamination of the ingot and damaging the header, it also raises the cost of production. If, for example, the initial electrode is 300 inches in length and the direct arcing of the electrode must be ended around 3–5 inches from the weld of the electrode to the header, that 3–5 inches of electrode are waste material. The 3–5 inches of titanium may weigh around 500 lbs and the scrapping of this quantity of material from each phase of the melting process adds considerably to the costs of production. Furthermore, because accidental arcing and subsequent damage to the header may occur, there may be a need for the header to be periodically rebuilt or repaired. This again increases the cost of production. 
   There is therefore a need in the industry for a method of manufacturing electrodes in a more efficient and less expensive manner. 
   BRIEF SUMMARY OF THE INVENTION 
   An objective of the invention is to provide a reusable header for manufacturing electrodes and more specifically to provide a header that is easily attached and detached to an electrode. 
   A second objective of the invention is to provide a reusable header that will tend to reduce foreign material contamination of the electrode if the header is accidentally arced and partially melted during manufacture. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiments of the invention, illustrative of the best mode in which applicant has contemplated applying the principles, are set forth in the following description and are shown in the drawings and are particularly and distinctly pointed out and set forth in the appended claims. 
       FIG. 1  is a partial cross-sectional front view of a first embodiment of a furnace with a reusable header in accordance with the present invention; 
       FIG. 1A  is a partial cross-sectional front view of a furnace with a reusable header in which the electrode is welded directly onto the header; 
       FIG. 1B  is a partial cross-section front view of a furnace with a reusable header showing the crucible having a solid bottom plate onto which a starter stub is placed; 
       FIG. 2  is a partial cross-sectional front view of the furnace showing molten metal building up within the crucible; 
       FIG. 3  is front view of the reusable header in accordance with the present invention; 
       FIG. 4  is a bottom view of the reusable header of  FIG. 3 ; 
       FIG. 5  is a top view of the starter stub for engagement with the reusable header; 
       FIG. 6  is a front view of the starter stub that engages the reusable header; 
       FIG. 7  is a partial cross-sectional bottom view showing the starter stub engaged with the header; 
       FIG. 8  is a partial cross-sectional side view through line  8 — 8  of  FIG. 7 , showing the starter stub engaged with the header; 
       FIG. 9  is a partial cross-sectional front view of the furnace showing the second melt and the formation of a more refined ingot in the crucible; 
       FIG. 10  is a partial cross-sectional front view of the furnace showing the final melt and showing the remnant of the previously melted electrode attached to a starter stub being remelted in the crucible; 
       FIG. 11  is a front view of a second embodiment of the reusable header in accordance with the present invention; 
       FIG. 12  is a bottom view of the reusable header of  FIG. 11 ; 
       FIG. 13  is a top view of the starter stub for engagement with the reusable header of  FIG. 11 ; 
       FIG. 14  is a front view of the starter stub; 
       FIG. 15  is a partial cross-sectional bottom view showing the starter stub engaged with the header; 
       FIG. 16  is a partial cross-section side view through line  16 — 16  of  FIG. 15  showing the starter stub engaged with the header; 
       FIG. 17  is a partial cross-sectional front view of the second embodiment of the reusable header, wherein an ingot is being molded in a form disposed in the crucible; 
       FIG. 18  is a partial front view an electrode that has been molded in the form, the electrode being shaped to engage the reusable header of  FIG. 11 ; 
       FIG. 19  is a cross-sectional bottom view of the electrode engaged in the header; 
       FIG. 20  is a partial cross-sectional side view through line  19 — 19  of  FIG. 19  showing the electrode engaged in the header; 
       FIG. 21  is a partial cross-sectional front view of the furnace showing a second melt and the molding of a more refined ingot in the form; 
       FIG. 22  is a partial cross-sectional front view of the furnace showing a final ingot of the desired metallurgical quality being formed. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIGS. 1–10 , there is shown a vacuum arc remelting furnace, generally referred to by the number  10 , having a crucible  12  and a housing  14 . A reusable header  18  in accordance with the present invention is preferably detachably connected to a ram  20 . Header  18  may engage a plate or starter stub  70  that supports an electrode  16  as is shown in  FIG. 1 . Alternatively, electrode  16  may be directly welded onto header  18  as is shown in  FIG. 1A . Header  18  may be manufactured from a variety of materials including steel or titanium without departing from the spirit of the invention. Ram  20  moves header  18 , and therefore starter stub  70 , if provided, and electrode  16 , toward or away from a mold  30  in crucible  12 . Electrode  16  is heated by a direct current arc  56  to a temperature sufficient to melt electrode  16 . The molten metal  57  from electrode  16  falls onto a second starter stub  72  disposed within crucible  12 . The molten metal accumulates on second starter stub  72  and solidifies to form an ingot  32  that becomes integrally bonded with second starter stub  72 . As is shown in  FIG. 1 , ingot  32  and second starter stub  72  may be withdrawn from crucible  12  by lowering a ram  218  from the lower end  12   b  of crucible  12  and ingot  32  may then be used as an electrode  32 A ( FIG. 9 ) in further processing of the metal or in other industrial applications. Alternatively, as is shown in  FIG. 1B , the molten metal may accumulate on a second starter stub  72   a  that is placed on the bottom plate  219  of crucible  12 . Ingot  32 , once formed on second starter stub  72   a , may then be withdrawn from the upper end  12   a  of crucible  12  by a crane. Second starter stub  72   a , having recess  78   a  may then be engaged with a projection  80  on header  218  and ingot  32  may be used as an electrode  32 A. If ingot  32  is going to be used as electrode  32 A, the manufacturer may not need to allow ingot  32  to cool down completely before it can be attached to a header  18 ,  218 . This is because the attachment of ingot  32  to header  18 / 218  is made via second starter stub  72 . This possible reduction in cooling time may reduce both production time and the amount of energy needed to remelt electrode  32 A. 
   Furnace  10  includes a housing  14  disposed over crucible  12 . Housing  14  includes an outlet  22  that is connected to a vacuum system (not shown). The vacuum system evacuates air  58  from within housing  14 , thereby creating a vacuum within housing  14 . Crucible  12  may be generally cylindrical in shape, having an inner lining  24  and a coaxial outer wall  25  which together form a compartment  26 . Compartment  26  of crucible  12  includes a water inlet  34  and a water outlet  36 . Water  27  entering compartment  26  through inlet  34  is circulated through compartment  26  and exits through outlet  36 . The circulating water  27  cools the molten metal within crucible  12  and this accelerates solidification of the molten metal into an ingot  32 . 
   Inner lining  24  is engaged by a plate proximate the lower end  12   b  of crucible  12 . The plate effectively seals the lower end  12   b  of crucible  12  and thereby forms a chamber or mold  30  in which an ingot  32  may be molded. This plate may be a starter stub as in  70  or  72  as shown in  FIG. 1  (or may be a form  100  as shown in  FIG. 17 ). 
   The following description will refer to second starter stub  72  only for the sake of clarity, but the description applies to other stubs which may be used in furnace  10 , such as starter stub  70 . Starter stub  72  is manufactured from substantially the same metal as is to be melted within furnace  10 . So, for example, if the metal to be melted in furnace  10  is a titanium alloy, then starter stub  72  will be manufactured from the same titanium alloy. If a variety of metals are to be melted in furnace  10 , then a plurality of starter stubs may be provided, each starter stub being manufactured from a different metal. Additionally, if the metal to be melted in the furnace will be remelted several times so that the metallurgical properties of the metal will be substantially different from the beginning of the process to the end of the process, then a plurality of starter stubs may be provided, each starter stub having different metallurgical properties and being utilized for the different steps in the remelting process. Furthermore, if it is desired to be able to easily visually distinguish the metallurgical qualities of a particular electrode from others produced in a series of melts, a plurality of starter stubs, of different thicknesses or colors or having differently shaped connections for engaging various headers, may be provided for attachment to electrodes having different metallurgical properties. 
   Starter stub  72  preferably has a substantially flat upper surface  74  and a shaped lower surface  76 . Lower surface  76  includes a recess  78  that is adapted to engage a complimentarily shaped projection  80  on header  218  or projection  82  on header  18 . Starter stub  72  may be supported proximate the lower end  12   b  of crucible  12  by second reusable header  218 , or it may be supported by a second ram (not shown) or it may rest against an interior bottom wall (not shown) of crucible  12 . Starter stub  72  is adapted to engage either reusable header  18  or second reusable header  218 . Both reusable header  18  and second reusable header  218  are preferably manufactured from substantially the same metal that is to be melted in the vacuum arc furnace. So, for example, if the metal to be refined in the furnace is titanium, then header  18  and header  218  are preferably manufactured from titanium. A number of different reusable headers may be provided if furnace  10  is to be used to melt a variety of different metals or if different metallurgical quality metals need to be separated for easy identification. For example, if one type of metal, titanium for example, is to be melted several times in the furnace to obtain a final ingot of substantially different metallurgical quality from the initial material, then a number of reusable headers having differing metallurgical properties may be provided for use with furnace  10 . This decreases the possibility of contamination of the ingot  32  with a foreign metal or with a metal of substantially different metallurgical quality. However, a conventional steel header may also be utilized with starter stub  72  without departing from the spirit of the present invention. In this instance starter stub  72  may be considered to be a detachable section of the header where the header is made of steel and the starter stub  72  is made from substantially the same metal to be melted in furnace  10 . 
   The following description will reference header  218  only for the sake of clarity, but it applies equally to header  18 . Header  218  includes a base  218   a  that is preferably integrally formed with a coaxial shaft  218   b . Shaft  218   b  is substantially cylindrical in shape and is adapted to receive ram  20  ( FIG. 4 ) or another ram (not shown) either therein or thereover. Shaft  218   b  is connected to ram  20  by way of rivets, screws, interlocking components or any other suitable mechanism known in the art. Base  218   a  is provided with a dovetail-shaped projection  80  that is adapted to be received within the complimentarily shaped and configured dovetailed-shaped recess  78  in starter stub  72 . While projection  80  and recess  78  are shown as being a traditional dovetail, it will be understood by those skilled in the art that any other suitable complimentarily shaped and configured projection and recess combination may be utilized to link the header  218  to starter stub  72 . Screws extend through apertures  79  to force the walls of projection  80  into abutting engagement with the walls of recess  76 . 
   Furnace  10  is used in the following manner. Starter stub  70  and electrode  16  are attached to header  18  as shown in  FIG. 1 . Header  18  with attached electrode  16  is lowered into crucible  12  to allow the metal from electrode  16  to be melted by direct current arc  56 . Electrode  16  may be formed from scrap materials that are melted together in a plasma consolidation furnace by plasma arc melting or it may be formed by melting the scrap materials together with an electron beam. Alternatively, the scrap materials may be conventionally welded together. In the case of titanium or titanium alloys, electrode  16  may be formed by melting scrap pieces of metal such as titanium sponge compacts and bulk scrap pieces onto starter stub  70  in a plasma consolidation furnace (not shown). Starter stub  70  is placed into the plasma consolidation furnace and the scrap pieces are deposited into the furnace over starter stub  70  and the pieces are melted to a temperature just sufficient to bond them together and to starter stub  70 . Alternatively, the scrap pieces may be bonded together as previously described and then the bonded mass may be conventionally welded directly onto starter stub  70 . Starter stub  70  is then engaged with reusable header  18  by sliding the two components together so that dovetail-shaped projection  82  on header  18  engages the recess  84  on starter stub  70 . Screws  86  are utilized to force the walls of projection  82  into abutting engagement with the walls of recess  84 . Electrode  16  is lowered into the crucible by ram  20 . A direct current arc  56  is struck between a first end  16   a  of electrode  16  and upper surface  74  of starter stub  72 . Arc  56  heats electrode  16  to a temperature sufficient to melt the metal of electrode  16  and the molten metal  57  falls onto upper surface  74  of starter stub  72  and begins to accumulate. As the metal from electrode  16  falls onto starter stub  72 , the upper surface  74  of starter stub  72  is partially melted by the hot molten metal. The molten metal is slowly cooled by water  27  circulating through compartment  26  and it begins to solidify and form an ingot  32 . The ingot  32  becomes integrally attached to upper surface  74  as the metal solidifies. Molten metal continues to drip off first end  16   a  of electrode  16  onto the forming ingot  32 . As the molten metal is hot, it partially remelts the upper surface of ingot  32 , forming an ingot pool  38 . The direct current arc  56  is then struck between first end  16   a  of electrode  16  and ingot pool  38 . As electrode  16  melts and becomes smaller in size, ram  20  may be lowered in the direction of Arrow A ( FIG. 1 ) to more or less maintain the gap X between the first end  16   a  of electrode  16  and ingot pool  38 . Alternatively, ram  20  may be raised in the direction of arrow B to maintain the gap X between the first end  16   a  and ingot pool  38  as the ingot  32  increases in size. Alternatively, as the size of ingot  32  increases, starter stub  72  may be lowered out of crucible or hearth  12  in the direction of arrow C ( FIG. 2 ) by second reusable header  218  to keep the relative distance X fairly constant. Electrode  16  is melted substantially completely so that all that remains is header  18  and starter stub  70 . It will be understood by those skilled in the art that at least a part of starter stub  70  may be arced and melted into crucible  12 . This tends to result in minimal contamination of ingot  32  because starter stub  70  is made from substantially the same material as is present in electrode  16 . Eventually, ingot  32  solidifies completely and then starter stub  72  with attached ingot  32  may be withdrawn from crucible  12 . The withdrawal may be accomplished by removing the starter stub  72  and ingot  32  through the upper end  12   a  of crucible  12  in the direction of Arrow A by way of a crane or through the lower end  12   b  of crucible  12  in the direction of Arrow C. The latter instance may be accomplished by the second reusable header  218  being connected to a second ram (not shown) and then being withdrawn in the direction of Arrow C ( FIG. 2 ). Starter stub  72 , with integrally attached ingot  32 , may remain connected to second reusable header  218  for further processing. Second reusable header  218  with starter stub  72  and ingot  32  may be inverted and attached to ram  20  (as shown in  FIG. 9 ) and then lowered into crucible  12 . Ingot  32  is then utilized as an electrode  32 A and can be remelted to produce a more refined ingot  48 . Alternatively, header  218  with starter stub  72  and ingot  32  attached thereto may be shipped to another location for other industrial applications. Alternatively, starter stub  72  and integral ingot  32  may be detached from second reusable header  218  and then they may be attached to a different header for use in another crucible (not shown) or may be attached to reusable header  18 . It will be understood by those skilled in the art that starter stub  70  may be reused by welding a second amount of scrap materials, titanium sponge compacts and bulk scrap pieces to it and then re-engaging starter stub  70  with header  18 . 
   In the next step and referring to  FIGS. 9 and 10 , starter stub  72  with electrode  32 A is lowered by ram  20  into crucible  12 . A direct current arc  56  is struck between electrode  32 A and a third starter stub  90 . Electrode  32 A is heated to the until metal begins to melt off it and drop onto the upper surface  92  of starter stub  90 . The molten metal drips onto upper surface  92  and as the molten metal it is hot it partially melts upper surface  92 . The molten metal is cooled by water  27  circulating in compartment  26 . Eventually a second ingot  48  begins to solidify and it becomes integrally bonded with upper surface  92  of third starter stub  90 . As molten metal  57  continues to fall from electrode  32 A, an ingot pool  50  is formed. Second electrode  32 A may be melted down to the point that it is substantially consumed and only starter stub  72  remains connected to header  218 . Accidental arcing of starter stub  72  or header  218  may occur at this stage, but because starter stub  72  and possibly header  218  are manufactured from substantially the same metal as electrode  32 A, there will not be much contamination of ingot pool  50 . As the size of second ingot  48  increases the size of the gap Y between lowermost end  35  and ingot pool  50  is maintained fairly constant by adjusting the position of ram  20  or starter stub  90  as described with reference to  FIG. 1 . Header  218  is then raised in the direction of arrow D, screws  81  are disengaged and starter stub  72  may then be removed from header  218  and be repositioned in crucible  12  for reuse. 
   Second ingot  48  solidifies in the manner previously described and may then be withdrawn from mold  30  either by lifting it out of the upper end  12   a  of crucible  12  by crane or lowering it out of lower end  12   b  by a second ram (not shown). Second ingot  48  is integrally bonded with third starter stub  90 . Third starter stub  90  and ingot  48  may be shipped as a unit for other industrial applications, or they may be shipped with another reusable header  300  interlocked with third starter stub  90  or they may be connected to either reusable header  18  or reusable header  218 . As previously described, if second ingot  48  is to be used as an electrode, it does not need to be allowed to cool before being repositioned in crucible  12  for remelting. As shown in  FIG. 10 , third reusable header  90  may be interlocked with reusable header  218  and then ingot  48  may be used as an electrode  48 A to further refine the metal. In this instance, the projection  80  engages in recess  94  on third starter stub  90 . Screws  81  are engaged to force the walls of projection  80  into engagement with the walls of recess  94 . 
   Occasionally, starter stub  72  may include a remnant of ingot  32 A. In this instance, starter stub  72  and the attached remnant of ingot  32 A may be attached to a reusable header  300  and form the bottom wall of crucible. A direct current arc  56  is struck between the remnant of ingot  32 A and the lowermost end  96  of electrode  48 A. Electrode  48 A melts and the molten material  57  drips down and is deposited onto the remnant of ingot  32 A. The molten metal melts the surface  35  and part or all of the remnant of ingot  32 A. The molten metal cools and a final ingot  120  begins to form within mold  30 . Ingot  120  is integral with any metal remaining from the remnant of ingot  32 A and ingot  120  is attached either directly or indirectly to starter stub  72 . An ingot pool  122  forms as molten metal  57  continues to drip from ingot  48 A. Eventually, the final ingot  120  solidifies and it and starter stub  72  may be removed from crucible  12  as previously described. The final ingot  120  is of higher metallurgical quality than electrode  48 A, electrode  32 A and electrode  16  because additional impurities have been removed during the remelting of the ingot  48 A. Final ingot  120  may be utilized in other manufacturing processes as desired. 
   A second embodiment of the header  318  is shown in  FIGS. 11 through 22 . Referring to  11 – 16 , it will be seen that header  318 , a starter stub  320  and an electrode  322  may be attached to each other in a different manner. In this instance, header  318  is provided with a dovetail recess  324  and starter stub  320  is provided with a complimentarily shaped and configured dovetail projection  326 . Electrode  322  is integrally bonded with starter stub  320  in the same manner as was described with reference to  FIGS. 1 through 10 . Screws  328  extend through apertures  330  to force the walls of projection  326  into abutting engagement with the walls of recess  324 . In use, starter stub  320  is moved horizontally with respect to header  318  so that projection  326  slides into recess  324 . Screws  328  are engaged to lock starter stub  320  and header  318  together. Header  318  may then be engaged with ram  20  and lowered into crucible  12  where a direct current arc is struck to melt electrode  322 . When electrode  322  is essentially consumed, screws  328  are disengaged and starter stub  320  with a remnant of electrode  322  may be removed from header  318 . 
   Referring to  FIGS. 17 through 22 , the second embodiment of reusable header  318  may also be used to engage a specially molded electrode as hereinafter described. Initially, header  318  is connected to a starter stub  420  onto which a first electrode  16  is bonded as described with reference to the first embodiment. Recess  324  of header  318  engages with a projection  424  that extends from starter stub  420 . Screws  328  lock header  318  and starter stub  420  together. A form  100  is disposed proximate the lower end  12   b  of crucible  12  to effectively seal crucible  12  and thereby create a mold  30  for formation of ingots therein. Form  100  is supported proximate the lower end  12   b  by a third ram  102 . Form  100  includes a shaped upper surface  104  and a substantially flat lower surface  106  that rests on third ram  102 . Upper surface  104  includes a dovetail-shaped recess  108 . Form  100  is manufactured from a metal that preferably melts at a higher temperature than the metal to be melted in furnace  10  such as that of electrode  16 . Alternatively, form  100  may be manufactured from a composite material that does not melt when heated. A film  101  of a releasing agent may be applied to upper surface  104  and recess  108 . A direct current arc  56  is struck between the lowermost end  16   a  of electrode  16  and upper surface  104  of form  100 . As before, lowermost end  16   a  is heated to a temperature sufficient to melt the metal and drops of molten metal  57  fall onto upper surface  104 . Recess  108  is filled and then molten metal overflows recess  108  and covers upper surface  104 . As molten metal accumulates over form  100 , the water  27  in compartment  26  causes the same to cool and an ingot  132  begins to form on form  100 . Continued melting of electrode  16  causes the formation of an ingot pool  138 . Once ingot  132  is completely solidified, ingot  132  is removed from crucible  12  either through upper end  12   a  by way of a crane or through lower end  12   b  by the lowering of ram  102  as previously described. At this stage ingot  132  is interlocked with form  100 . The two components are moved horizontally with respect to each other and projection  110  on ingot  132  slides out of recess  108  on form  100 . Ingot  132  is then available for attachment to a reusable header such as header  318  or it may be shipped to another location for further industrial processing. As was previously described, while projection  110  and recess  108  are indicated to be dovetail-shaped, it will be understood by those skilled in the art that any other suitably shaped recess and projection may be utilized without department from the spirit of the present invention. Starter stub  420  may be removed from header  318  and ingot  132  may be attached to header  318 . This is achieved by moving the two components horizontally relative to each other so that projection  110  on ingot  132  slides into recess  324  on header  318 . Screws  328  are engaged to lock the walls of projection  110  in abutting relationship with the walls of recess  324 . Ingot  132  may then be used as an electrode  132 A ( FIG. 21 ) and may be lowered by ram  20  into crucible  12  for remelting. Form  100  may be reinserted into the lower end  12   b  of crucible  12  and a releasing agent film  101  applied thereto. A direct current arc  56  is struck between upper surface  104  of form  100  and lower surface  135  of electrode  132 A. A new ingot  148  and ingot pool  150  are formed in the manner previously described. Once ingot  148  is solidified, form  100  is removed from crucible  12  as previously described. Ingot  148  is released from form  100  and may then be engaged with header  318  by interlocking projection  210  on ingot  148  with recess  324  on header  318 . Ingot  148  may then be used as an electrode  148 A. Form  100  with releasing film  101  may then be reinserted into crucible  12  and a direct current arc  56  is struck between the lower surface  150  of electrode  148 A and upper surface  104  of form  100 . A final ingot  190  is produced as previously described. Final ingot  190  is of improved metallurgical quality with respect to electrodes  148 A,  132 A and  16 . It will be understood in the art that a plurality of differently shaped forms  100  may be utilized so that they may be attached to differently configured headers to allow the manufacturer to identify different metallurgical quality electrodes. 
   It will be understood by those skilled in the art that a manufacturer may use a combination of different starter stubs  72 , forms  100  and headers to producing differently shaped and configured electrodes. These different configurations will depend on the end use of the electrodes by the manufacturer and any customers of the manufacturer. For example, the same header may be utilized for attachment of a plurality of electrodes or, alternatively, a series of identical headers may be utilized throughout the remelting process or alternatively a series of different headers and complimentarily shaped electrodes or starter stubs may be utilized throughout the remelting process. It will be understood by those skilled in the art that it is possible to put together a series of reusable headers and/or bottom plates with molds to allow for a series of differently shaped ingots/electrodes to be created by the above-described process. Whatever the combination desired by the user, it will be understood by those skilled in the art that the reusable headers are made of a metal that is of similar metallurgical quality to the electrode to be melted. 
   In the foregoing description, certain terms have been used for brevity, clearness, and understanding. No unnecessary limitations are to be implied therefrom beyond the requirement of the prior art because such terms are used for descriptive purposes and are intended to be broadly construed. 
   Moreover, the description and illustration of the invention is an example and the invention is not limited to the exact details shown or described.