Method of manufacturing elongate members and workpiece therefor

Abstract

A method of forming an elongate composite product wherein a composite body formed of an internal billet and an external sleeve is assembled, the interior periphery of the sleeve being complimentary to the exterior periphery of the billet, the composite body then being formed as by extruding into an elongate product having an inner core and an outer sheath.

1 . A method of forming an elongate composite product comprising: 
 forming a billet of a first metallic material, said billet having an outer peripheral surface;    forming a sleeve of a second metallic material, said sleeve having an inner peripheral surface, said inner and outer peripheral surfaces being complimentary to one another;    shrink fitting said billet in said sleeve to form a composite body; and    forming said composite body into an elongate product.    
   
   
       2 . The method of  claim 1 , wherein said billet comprises a tubular member.  
   
   
       3 . The method of  claim 1 , wherein said billet comprises a solid member.  
   
   
       4 . The method of  claim 2 , wherein said tubular member comprises a corrosion prone material.  
   
   
       5 . The method of  claim 4 , wherein said sleeve comprises a corrosion resistant material.  
   
   
       6 . The method of  claim 3 , wherein said billet comprises a corrosion prone material.  
   
   
       7 . The method of  claim 6 , wherein said sleeve comprises a corrosion resistant material.  
   
   
       8 . The method of  claim 1 , wherein said sleeve has a first end and a second end and further comprising: 
 securing a first end cap to said sleeve on said first end;    securing a second end cap to said sleeve on said second end, said billet being confined by said sleeve and said first and second end caps to form a composite body.    
   
   
       9 . The method of  claim 8 , wherein said first and second caps are attached to said sleeve by welding.  
   
   
       10 . The method of  claim 8 , comprising removing said first and second end caps from said elongate product.  
   
   
       11 . A method of forming an elongate composite product comprising: 
 forming a billet of a first metallic material, said billet having an outer peripheral surface;    forming a sleeve of a second metallic material, said sleeve having a first end, a second end and an inner peripheral surface, said inner and outer peripheral surfaces being complimentary to one another; and    positioning said sleeve over said billet;    securing a first end cap to said sleeve on said first end;    securing a second end cap to said sleeve on said second end, said billet being confined by said sleeve and said first and second end caps to form a composite body; and    forming said composite body into an elongate product.    
   
   
       12 . The method of  claim 11 , wherein said billet comprises a tubular member.  
   
   
       13 . The method of  claim 11 , wherein said billet comprises a solid member.  
   
   
       14 . The method of  claim 11 , wherein said first and second ends are attached to said sleeve by welding.  
   
   
       15 . The method of  claim 8 , comprising removing said first and second end caps from said elongate product.  
   
   
       16 . The method of  claim 11 , comprising shrink fitting said billet in said sleeve.  
   
   
       17 . A workpiece for forming into an elongate product comprising: 
 a billet having an outer surface;    a sleeve having a first end and second end and an inner surface, said inner surface conforming to said outer surface, said billet being received in said sleeve;    a first end cap attached to said first end of said sleeve; and    a second end cap attached to said second end of said sleeve.    
   
   
       18 . The workpiece of  claim 17 , wherein said first and second end caps are attached by welding.  
   
   
       19 . The workpiece of  claim 17 , wherein said first cap comprises a body portion and a neck portion, said neck portion having a peripheral outer surface conforming to said inner surface, said neck portion being received in said first end of said sleeve.  
   
   
       20 . The workpiece of  claim 17 , wherein said billet comprises a solid member.  
   
   
       21 . The workpiece of  claim 17 , wherein said billet comprises a tubular member.  
   
   
       22 . The workpiece of  claim 20 , wherein said sleeve comprises a corrosion resistant material.  
   
   
       23 . The workpiece of  claim 20 , wherein said billet comprises a corrosion prone material.  
   
   
       24 . The workpiece of  claim 21 , wherein said tubular member comprises a corrosion prone material.  
   
   
       25 . The workpiece of  claim 22 , wherein said sleeve comprises a corrosion resistant material.  
   
   
       26 . The workpiece of  claim 13 , wherein said first and second end caps have a peripherally extending outer surface conforming to said outer surface of said sleeve.  
   
   
       27 . The workpiece of  claim 17 , wherein said billet is shrink fitted in said sleeve.  
   
   
       28 . A workpiece for forming into an elongate product comprising: 
 a billet having an outer surface;    a sleeve having a first end and second end and an inner surface, said inner surface conforming to said outer surface, said billet being shrink fitted in said sleeve.    
   
   
       29 . The workpiece of  claim 28 , wherein said billet comprises a solid member.  
   
   
       30 . The workpiece of  claim 28 , wherein said billet comprises a tubular member.  
   
   
       31 . The workpiece of  claim 29 , wherein said sleeve comprises a corrosion resistant material.  
   
   
       32 . The workpiece of  claim 31 , wherein said billet comprises a corrosion prone material.  
   
   
       33 . The workpiece of  claim 30 , wherein said tubular member comprises a corrosion prone material.  
   
   
       34 . The workpiece of  claim 33 , wherein said sleeve comprises a corrosion resistant material.  
   
   
       35 . The workpiece of  claim 28 , wherein said sleeve has first and second ends and, a first end cap being attached to said first end, a second end cap being attached to said second end.  
   
   
       36 . The workpiece of  claim 35 , wherein said first and second end caps have a peripherally extending outer surface conforming to said outer surface of said sleeve.  
   
   
       37 . The workpiece of  claim 35 , wherein said first end cap has a body portion and a neck portion, said neck portion having an outer peripheral surface conforming to said inner surface, said neck portion being received in said first end of said sleeve.  
   
   
       38 . The method of any of claims  1  or  11 , wherein said forming comprises extruding.