Patent Publication Number: US-6904657-B2

Title: Brittle wire extrusion method and apparatus

Description:
CROSS REFERENCE TO RELATED PATENT APPLICATIONS 
     There are no related pending patent applications filed by me. 
     BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention is in the general field of manufacture of metallic wires; 
     The invention is more particularly in the field of manufacture of wire and other elongate members from high performance brittle alloys; 
     The invention is even more directly in the field of manufacture of such products by specialized, novel, unique and useful variations involved in the filled billet extrusion technique. 
     II. Description of the Prior Art 
     There is considerable prior art in this field. The following United States Patents reveal the state of the art prior to my present invention:
         U.S. Pat. No. 4,209,122 discloses a method of making high performance alloy wire;   U.S. Pat. No. 3,788,820 discloses the making of high performance alloy members by the Filled Billet Extrusion Method;   U.S. Pat. No. 3,394,213 discloses the production of fine filaments through an interesting process involving some of the known extrusion processes and an acid solution process;   U.S. Pat. No. 4,606,884 combines a number of pressing, machining and acid solution steps;   U.S. Pat. No. 2,050,298 defines a process for reducing rods, wires, etc. by surrounding preforms with a brittle filler and performing a number of physical steps without using acid;   U.S. Pat. No. 4,209,122 defines a process to produce high performance alloy wires, etc. utilizing the principles set forth in many of the foregoing patents;   U.S. Pat. No. 4,777,710 includes the features of U.S. Pat. No. 4,209,122 particularly utilizing a chromium filler powder in the process; and   U.S. Pat. No. 6,308,392 B1, of which I am a co-inventor, represents a major step forward in this art.       

     None of the prior art has solved a particularly costly deficiency in this art which is the bursting of the can used in this art due to collapse of the block nose during the extrusion. 
     SUMMARY OF THE INVENTION 
     High performance brittle alloy wires and the like are used extensively in various critical manufacturing processes and the like. They are particularly used in critical welding of various sensitive items, such as in aircraft welding and the like. 
     As will be understood by those skilled in the art, critical components must be addressed with the highest regard for performance and reliability since safety is a prime consideration. As a result, those engaged in production of high performance brittle alloy items are constantly seeking even the most minute improvement and innovation in manufacturing methods and the like. 
     I have previously mentioned some of the most important prior art in this field. Considering all of the innovations and improvements heretofore developed, I have still found deficiencies in the processes concerned. Particularly, the processes disclosed in the patents mentioned above, including U.S. Pat. No. 6,308,392 B1 of which I am a co-inventor fail to solve some severe deficiencies in this particular field. Those deficiencies include frequent bursting of the can used in this art due to collapse of the block nose during the extrusion; low yield of actual usable final product as compared to amount of untreated product actually required; excessive labor and operations required to finish the product of the co-extrusion process; danger of injury to personnel and machinery; excessive cost of finished product produced; and associated deficiencies. I have conceived and perfected solutions to these problems which are disclosed in this specification. The solutions are primarily related to unobvious, novel, unique and useful can design and product assembly and processing techniques. 
     It is an object of this invention to provide an improved and economical method for the manufacture of brittle alloy elongate shapes by the brittle wire co-extrusion method wherein the tendency of the can used in this process to burst during the extrusion is eliminated; 
     Another object of this invention is to eliminate excessive waste in collapse and bursting of cans used in this extrusion process; 
     Another object of this invention is to avoid injury to persons and materials due to release of molten metal and impurities involved in collapsing and bursting of cans used in this extrusion process; 
     Another object of this invention is to provide such methods and means wherein there is a minimum of lost product due to the necessity of machining or other treatment of surfaces of salvaged material after collapsing and bursting of cans used in this extrusion process; 
     Another object of this invention is to minimize labor requirements in such method; 
     Another object of this invention is to maximize the quality of the brittle alloy products produced; 
     Another object of this invention is to maximize the quantity of the brittle alloy products produced; 
     Another object of this invention is to minimize the cost of the brittle alloy products produced. 
     The foregoing and other objects and advantages of this invention will be clear to those skilled in the art upon reading the following description of preferred embodiments in conjunction with a review of the appended drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a broken away schematic section of a billet according to the prior art about to enter an extrusion die; 
         FIG. 2  is a broken away schematic section of the nose of the billet of  FIG. 1  according to the prior art showing bursting after passing through the extrusion die; 
         FIG. 3  is a broken away schematic section of a billet according to my present invention about to enter an extrusion die; 
         FIG. 4  is a schematic section of the billet of  FIG. 3  according to my present invention after passing through the extrusion die; 
         FIG. 5  is a schematic broken away perspective of the rear of the billet of  FIG. 3  showing vent holes according to this invention; and 
         FIG. 6  is a block diagram of a method in accordance with the present invention. 
     
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     The items having reference numerals in the drawings are: 
     
       
         
           
               
               
             
               
                   
               
               
                 Numeral 
                 Item 
               
               
                   
               
             
            
               
                 10 
                 extrusion die 
               
               
                 11 
                 die orifice 
               
               
                 12 
                 chamfered entry to die orifice 
               
               
                 20 
                 billet according to prior art 
               
               
                 21 
                 can 
               
               
                 21a 
                 ruptured can wall 
               
               
                 22 
                 front end plate 
               
               
                 22a 
                 burst front end plate 
               
               
                 23 
                 rods and powder 
               
               
                 23a 
                 reduced diameter rods 
               
               
                 23b 
                 molten rods exiting ruptured can 
               
               
                 24 
                 area immediately behind front end plate 
               
               
                 25 
                 molten material 
               
               
                 50 
                 extrusion die 
               
               
                 51 
                 die orifice 
               
               
                 52 
                 chamfered entry to die orifice 
               
               
                 60 
                 billet according to present invention 
               
               
                 61 
                 can 
               
               
                 61a 
                 reduced diameter can 
               
               
                 62 
                 concave front end plate 
               
               
                 62a 
                 collapsed front end plate 
               
               
                 63 
                 rods and powder 
               
               
                 63a 
                 reduced diameter rods 
               
               
                 64 
                 front of billet behind collapsed concave front end plate 
               
               
                 65 
                 chamfered can front end 
               
               
                 66 
                 cropped rear end of billet 
               
               
                 66a 
                 crop line 
               
               
                 67 
                 rear end plate 
               
               
                 68 
                 vent holes 
               
               
                 69 
                 vent holes 
               
               
                 70 
                 chamfered edge and weld of rear end plate 
               
               
                   
               
            
           
         
       
     
     This invention consists of improvements and innovations in the filled billet extrusion method, which method, prior to the invention disclosed in the previously mentioned U.S. Pat. No. 6,308,392 B1 is well known to those skilled in the art. For this reason and in the interests of expediency, full details of the filled billet extrusion method will not be listed, but only those portions necessary for a complete understanding of the novel features of my invention. 
     In  FIG. 1  a portion of a billet  20  including a nose plate  22  about to enter a die  10  for extrusion through the die orifice  11  a customary manner. The entry to the die orifice is chamfered  12 . The entire billet  20  will be forced through the die orifice an hydraulic ram or the like as is known to those skilled in the In extruding the billet in this manner the goal is that the meter of the can  21  will be reduced  21   a  and elongated and that rods  23  in metallic and other powder will likewise be reduced and elongated  23   a.    
       FIG. 2  shows what actually happens in a great number of cases. The front plate  22  is distorted and bursts  22   a  causing the virtual explosion of the front end with dangerous and costly release of gases and molten material  25 . Additionally the can will rupture along its length  21   a  and rods and other material  23   b  will be discharged. Such items are ruined and cannot be reclaimed. Additionally, there is great danger to personnel, buildings and equipment since these forces are very great and become totally explosive. 
       FIGS. 3 ,  4 , and  5  illustrate the features of my new invention. The invention consists of special shaping of the front end of the can and the front end closure, and special venting at the rear of the can. 
     The die  50  and die orifice  51  are unchanged from the prior art. However, the new billet  60 , can  61 , and the concave front end plate  62  have revolutionized this procedure. I have chamfered  65  the front end of the can  61  to match the chamfer of the entry  52  to the die orifice. I have also secured (by welding or the like) the concave front plate  62  to the interior of the can and at a slight distance behind the front chamfer  65  of the can. I also provide a defined space filled with metallic powder or the like  64  between the front end plate and the ends of the rods  63 . 
     The result of these novel, unique and useful inventions is that the front end of the billet collapses as shown at  62   a  with the powder  64   a  forming a buffer to the rods now reduced and elongated  63   a  within the reduced and elongated can  61   a . The successfully extruded elongated rods  63   a  and can  61   a  are now cropped, or severed at  66   a  adjacent the die orifice as is known to those skilled in the art from the small length  66  of the rear of the original billet. 
     The rods  63   a  are now removed from the can as described in U.S. Pat. No. 6,308,392 B1 or other suitable manner as is known to those skilled in the art. 
     In addition to my new process involving the front end of the billet as previously described, I have discovered that special formation of vent holes at the rear of the billet gives additional benefits and improves the performance, yield, and safety of this process. It has been customary to provide a single vent hole in the rear plate  67  of the can. However, I have carefully calculated the formation of gases within the billets and have found that much better venting and performance can be achieved by spacing three vent holes  68  in the rear end plate  67  around the perimeter and near the inner surface of the can as shown in FIG.  5 . Also, two vent holes  69  (one vent  69  indicated by an arrow is not visible) through the can  61  provide additional beneficial results. All of these vents can be of varying sizes which can be determined empirically to accommodate the exact conditions of size and make up of the cans, rods, powders, and the like for any particular extrusion. 
     It is to be understood that the loading, preparation, treatment and the like of the rods and other matter into the can as well as the removal after extrusion are, except as otherwise described above, routine and known to those skilled in the art and exemplified in the various patents referenced above. 
     The claims and abstract which follow are incorporated herein as a part of the disclosure the same as though fully set forth again. 
     While the embodiments of this invention shown and described are fully capable of achieving the objects and advantages desired, it is to be understood that they have been shown for purposes of illustration only and not for purposes of limitation. 
     In the claims which follow if I should omit to claim patentable feature of this invention such failure is due to inadvertence an not due to any intent to dedicate or abandon such feature. In such event upon learning of such omission I shall immediately take any appropriate and authorized action to cure such omission, and claim such feature.