Abstract:
A method for compounding an alloy includes the step of forming a first batch of the base metal and tracking the first batch through the process. The master alloy is added to the first batch based on the weight of the base metal. In one embodiment, the master alloy is added to meet a desired percentage. In another embodiment, the master alloy is added to meet a desired total weight. When the total weight criteria is used, a computer tracks the weights of the batches and compensates for heavy batches with light batches and compensates for light batches with heavy batches in order to maintain the average weight of the batches at the desired total weight. The batches are briquetted and the composition of the briquettes are tracked. The briquettes are added to an electrode formation device and the position of the briquettes in the device is tracked so that the composition of the electrode can be identified.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention generally relates to methods for compounding alloys and, more particularly, to a process that divides a large batch of alloy materials into a plurality of accurately-measured smaller batches that each have the proper percentages of alloy materials in order to control and track the percentages of materials throughout the process of compounding the materials. The weight of small titanium batches are tracked by a computer that subsequently controls the addition of master alloy material to compensate for different amounts of titanium in the batches. The small mixed batches of titanium and master alloy are then briquetted and used to form an electrode ingots, slabs, pucks, or any manufactured near net shaped or net shaped products. 
     2. Background Information 
     Titanium alloy is currently produced by dividing a large amount of titanium material and master alloy material into a plurality of small batches that are briquetted and formed into an electrode. For instance, a 3000 pound batch of titanium and master alloy components may be processed in ten 300 pound batches. Although the 3000 pound batch included the proper percentages of materials, the percentages of materials in the 300 pound batches may be significantly different than the desired mixture of materials. When the mixture is off, the resulting electrode will include portions that have too much titanium and other portions that include too much master alloy. Forming electrodes in this way is undesirable because of the varying percentages of materials. The art thus desires a method of forming a titanium alloy electrode wherein the mixture of titanium and master alloy is tightly controlled to provide a uniform electrode. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is an objective of the present invention to provide a method for processing titanium alloys that mixes the alloy components in small batches. 
     Another objective of the present invention is to provide a method of processing titanium alloy that ensures each small batch of alloy materials has substantially the same composition of materials as all of the other small batches. 
     Another objective of the present invention is to provide a method of processing titanium alloy that ensures accurate compositions while enabling components to be reused if measured inaccurately. 
     Another objective of the invention is to provide a method of processing titanium alloy wherein the content of a series of small batches is tracked so that the contents of subsequent batches may compensate for earlier batches to maintain the overall consistency of the resulting electrode. 
     Another objective of the invention is to provide a method for processing an alloy having at least two components that must be mixed by a given percentage wherein the weight of the first material is measured and the second material is then added based on the weight of the first material and the given percentage. 
     Another objective of the present invention is to provide a method for processing an alloy whereby the contents of the alloy are divided into small batches and tracked throughout the entire process of mixing the components to forming an electrode. 
     These and other objectives and advantages ofthe invention are achieved by a method for compounding a base metal with a master alloy comprising the steps of: (a) providing a quantity of the base metal; (b) providing a quantity of the master alloy; (c) creating a first batch of the base metal; (d) identifying the weight of the first batch of base metal; (e) adding master alloy to the first batch of base metal to form a mixture batch; and (f) basing the weight of the master alloy added to the first batch of base metal on the weight of the first batch of base metal. 
     Other objectives and advantages of the invention are achieved by a method for compounding a base metal with a master alloy comprising the steps of: (a) providing a quantity of the base metal; (b) providing a quantity of the master alloy; (c) creating a first batch of the base metal; (d) identifying the weight of the first batch of base metal; (e) adding master alloy to the first batch of base metal to form a mixture batch; (f) creating a second batch of the base metal; and (g) basing the weight of the base metal in the second batch on the weight of the base metal in the first batch. 
     Further objectives and advantages of the invention are achieved by an apparatus for compounding a base metal with a master alloy; the apparatus comprising: a scale; a supply of base metal adapted to deliver base metal to the scale; a supply of master alloy adapted to deliver master alloy to the scale; a computer in communication with the scale; a computer adapted to identify the weight of material in the scale and store the weight in its memory; and a mixing conveyor adapted to selectively receive material from the scale. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The preferred embodiment of the invention, illustrative of the best mode in which applicant has contemplated applying the principles of the invention, is set forth in the following description and is shown in the drawing and is particularly and distinctly pointed out and set forth in the appended claims. 
     The drawing FIGURE is an overall schematic view of the processing line for accomplishing the method of the present invention. 
    
    
     Similar numbers refer to similar elements throughout the specification. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The method of the present invention is achieved by the processing line indicated by the numeral  10  in the accompanying drawings. The method of the present invention allows titanium alloy materials to be mixed in small batches while controlling the components ofthe small batches. To maintain consistency, the method of the present invention will base the contents of each small batch based on the contents of the immediately-preceding batch or a summary of proceeding batches. The small batches are tracked by a computer  12  so that the percentages of materials in the resulting electrode can be identified. 
     In the preferred embodiment of the invention, five base metal hoppers  14  are provided to initially hold the base metal to be alloyed. In the exemplary embodiment, the metal is titanium. The titanium may be in any of a variety of known forms when it resides in hoppers  14 . For example, the titanium may be a plurality of titanium chips or titanium sponge. 
     Hoppers  14  are positioned above a conveyor mechanism  16 . In the preferred embodiment of the invention, conveyor mechanism  16  is a vibratory feeder configured to slowly move material deposited on its upper surface  18  off of its feed end  20 . Other types of conveyor mechanism  16  may be used in alternative embodiments of the invention. 
     Feed end  20  of conveyor mechanism  16  is positioned above the inlet of a scale  22  that includes a conveyor outlet  24  and a reuse outlet  26 . Scale  22  is in communication with computer  12  so that computer  12  can identify and store the weight of the titanium material disposed in scale  22 . Computer  12  also assigns a batch number to the material in scale  22  so that the material may be tracked throughout the process. 
     If computer  12  determines that the weight of the material in scale  22  exceeds a limit set by the user of the method, computer  12  causes scale  22  to empty its contents through reuse outlet  26 . In the preferred embodiment, reuse outlet  26  empties into a reuse hopper  28 . Reuse hopper  28  may be periodically emptied back into hoppers  14  or may be continuously connected to hoppers  14  by a conveyor that automatically empties hopper  28  back into hoppers  14 . 
     When computer  12  determines that the weight of the material in scale  22  is in an acceptable range, computer  12  causes scale  22  to empty its contents through conveyor outlet  24  into a holding hopper  30 . Holding hopper  30  is positioned above a mixing conveyor  32  that includes a plurality of buckets  34 . In the preferred embodiment of the invention, buckets  34  are identified as buckets  34 A through  34 Z so that computer  12  may identify and track buckets  34  as they move along conveyor  32 . Buckets  34  may be identified by any of a variety of identifying indicia as known in the art. 
     Processing line  10  further includes a plurality of master alloy hoppers  40 . In the preferred embodiment of the invention, five master alloy hoppers  40  are provided to initially hold the master alloy to be mixed with the metal from hoppers  14 . In the exemplary embodiment, the master alloy is one of vanadium aluminum, aluminum molybdenum, aluminum zirconium sponge, or a variety of other known master alloys. 
     Hoppers  40  are positioned above a conveyor mechanism  42 . In the preferred embodiment of the invention, conveyor mechanism  42  is a vibratory feeder configured to slowly move material deposited on its upper surface  44  off of its feed end  46 . Other types of conveyor mechanism  42  may be used in alternative embodiments of the invention. 
     Feed end  46  of conveyor mechanism  42  is positioned above the inlet of a scale  48  that includes a conveyor outlet  50  and a reuse outlet  52 . Scale  48  is in communication with computer  12  so that computer  12  can identify and store the weight of the master alloy disposed in scale  22 . Computer  12  also assigns a batch number to the material in scale  48  so that the material may be tracked throughout the process. 
     If computer  12  determines that the weight of the material in scale  48  exceeds a determined value, computer  12  causes scale  48  to empty its contents through reuse outlet  52 . In the preferred embodiment, reuse outlet  52  empties into a reuse hopper  54 . Reuse hopper  54  may be periodically emptied back into hoppers  40  or may be continuously connected to hoppers  40  by a conveyor that automatically empties hopper  54  back into hoppers  40 . 
     When computer  12  determines that the weight of the material in scale  48  is in an acceptable range, computer  12  causes scale  48  to empty its contents through conveyor outlet  50  into a holding hopper  56 . Holding hopper  56  is positioned above mixing conveyor  32 . 
     In another embodiment of the invention, scale  22  may be used to measure both materials. In this embodiment, conveyor mechanisms  16  and  42  are controlled to stop placing material in scale  22  while the other conveyor is moving. 
     Processing line  10  further includes a collection hopper  60  positioned below the end  62  of mixing conveyor  32 . Collection hopper  60  empties into a mixer  64  that throughly mixes the titanium with the master alloy. Mixer  64  may be a rotary-type mixer or another suitable mixer as is known in the art. The outlet of mixer  64  is positioned to empty the contents of mixer  64  onto a conveyor  66  that moves the mixed materials into a briquetter  68 . 
     Briquetter  68  forms pucks  70  that are fed into a rotary screw drum  72  that feeds a device  78  that forms a consumable electrode out of pucks  70 . Computer  12  is in communication with rotary screw drum  72  so that computer  12  can track the position of the screw  74 . Computer  12  may thus identify the individual flights  76 A- 76 F within screw drum  72  and track the position of pucks  70  within screw drum  72 . 
     Having now described the components of the present invention, the method performed by processing line will now be described. In accordance with the objectives of the present invention, the method allows the consistency of the titanium and master alloy to be tightly controlled throughout the process so that the resulting consumable electrode has a consistent and identifiable composition. 
     The method starts at hoppers  14  where titanium is deposited onto conveyor  16 . Conveyor  16  slowly moves the titanium into scale  22  where computer  12  continuously (or periodically) weighs the contents of scale  22 . The user of the method defines the desired amount of titanium for each bucket  34 . For instance, the user may desire that each bucket  34  includes ten pounds of titanium. In this example, computer  12  continues to weigh the material in scale  22  until the weight reaches ten pounds. If ten pounds is not exactly reached, computer  12  compares the actual weight against an acceptable range to determine if the material in scale should be emptied into holding hopper  30 . If the range is exceeded, computer  12  directs the material in scale  22  into reuse hopper  28 . 
     When computer  12  empties the material in scale  22  into holding hopper  30 , computer  12  stores the exact weight of the batch in a manner that allows the weight to be readily identified. Holding hopper  30  holds the material until conveyor  32  positions an empty bucket  34  below hopper  30 . Hopper  30  then empties the material into bucket  34 . In this example, the bucket holding this material shall be referred to as bucket  34 A. Computer  12  then matches the identifying indicia of bucket  34 A with the weight recorded for the material emptied into bucket  34 A. 
     Once bucket  34 A is filled, conveyor  32  advances and the process of filling scale  22  and the next successive bucket  34 Z is repeated. Conveyor  32  then advances until bucket  34 A is positioned to receive the master alloy from holding hopper  56 . In the embodiment of the invention using one scale, bucket  34 A remains in place until loaded with master alloy. 
     The process of weighing the master alloy is essentially the same as the process of weighing the titanium except that the target weight is based on the weight of the batch of titanium in the target bucket. The mixing methodology must be selected by the user. The mixing methodology may require that each bucket  34  includes a target percentage of materials or that each bucket meets a target weight. In the first embodiment, the user may desire that each bucket includes 75 percent (by weight) master alloy and 25 percent (by weight) titanium without regard to the total weight of material in the bucket. In the other embodiment, the total weight of material in the bucket must equal a target weight (such as forty pounds) without regard to the percentages of materials. It is understood that essentially any percentage or any target weight may be used instead of these examples. 
     For example, the first mixing methodology requires computer  12  to base the target weight in scale  48  using the percentage method based on the weight of the base metal in bucket  34 A. If bucket  34 A has 9.5 pounds of titanium, computer  12  loads 28.5 pounds of master alloy into scale  48  before emptying into holding hopper  56 . The 9.5/28.5 mixture results in the target percentage. The method then continues by basing the next batch weight of base metal without any reference to the total weight of the previous batch. 
     In another embodiment, computer  12  records the total weight of the batch in bucket  34 A and compensates for the weight in the next successive batch or successive batches. For example, batch  34 A was thirty-eight pounds based on the percentage method. If the target weight for each batch is forty pounds, computer  12  measures the titanium for the next successive batch to be 10.5 pounds so that the master alloy will be 31.5 pounds causing the total batch weight to be forty-two pounds. The combination of batches  34 A and  34 B thus totaling eighty pounds. If the weight in bucket  34 B does not result in a perfect compensation to the target, computer  12  continues the compensation with bucket  34 C, and so on. 
     In the other mixing methodology, computer  12  only bases the weight of batches in buckets  34 A- 34 Z by a total target weight without measuring the percentage. In the above example, batch  34 A included 9.5 pounds of titanium. In this embodiment, computer  12  would then add 30.5 pounds of master alloy into bucket  34 A to make the total weight of bucket  34 A equal forty pounds. If the exact target weight is not achieved, computer  12  compensates by adding more weight or subtracting weight in the next successive bucket  34 B. For example, if bucket  34 A has 40.3 pounds of material, computer  12  loads bucket  34 B with 39.7 pounds of material. Again, if exact compensation cannot be achieved, computer  12  continues to compensate with the next successive bucket. In this methodology, computer  12  may also track the weights of base metal and master alloy so that a target percentage may also be met. 
     Another method for mixing the base metal and master alloy involves the step of defining a target weight of the base metal for each batch and determining the weight of a batch of base metal based on the weight of the base metal in a previous batch and the target weight. In this embodiment, the method does not involve the use of a target weight ratio. Specifically, the weight of the base metal in the first batch is compared to the target weight. The difference between the target weight and the weight of the base metal in the first batch is compensated for in the weight of the base metal added to the second batch so that the average of the weight of the base metal in the first and second batches is substantially equal to the target weight. The process can be repeated such that, for instance, a third batch of the base metal can be created where the weight of the base metal in the third batch is based on the weight of the base metal in the second batch and the target weight. 
     And yet another mixing methodology, an average error over the previous four batches is taken such that the target weight is adjusted by a small percentage based on the weight of each of the last four batches. In this manner, a tight target weight tolerance is followed similar to the percentage weight variance set forth above. 
     Buckets  34  are emptied into mixer  64  and mixed. Mixed batches are briquetted to form pucks  70  which are fed into a flight  76  of screw  74 . The batch from bucket  34 A is thus fed into flight  76 A which is also tracked by computer  12 . Computer  12  can thus identify the specific composition of the consumable electrode after the electrode is formed. Computer  12  can thus identify areas of the electrode where a higher percentage of titanium resides. 
     Accordingly, the improved method for compounding titanium is simplified, provides an effective, safe, inexpensive, and efficient device and method which achieves all the enumerated objectives, provides for eliminating difficulties encountered with prior devices and methods, and solves problems and obtains new results in the art. 
     In the foregoing description, certain terms have been used for brevity, clearness, and understanding; but 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 by way of example, and the scope of the invention is not limited to the exact details shown or described. 
     Having now described the features, discoveries, and principles of the invention, the manner in which the method and apparatus is constructed and used, the characteristics of the construction, and the advantageous new and useful results obtained; the new and useful structures, devices, elements, arrangements, parts, and combinations are set forth in the appended claims.