Variable thickness extrusion for variable extrudate product properties

Abstract

A method for solid phase processing (SPP) of a feedstock is provided. The method can include providing relative rotation and translation between an extrusion die and a feedstock, where the die has an extrusion aperture through which a tapered mandrel extends. A first and second extrudate portions can each be generated via the aperture. An axial position of the tapered mandrel can be adjusted relative to the die face during the rotation and translation such that a second extrudate portion is generated having a different inner dimension compared to the first portion, thereby varying a wall thickness between portions.

What is claimed is: 
     
         1 . A method for solid phase processing (SPP) of a billet or other feedstock, the method comprising:
 providing relative rotation and translation between an extrusion die and a feedstock, the die including an extrusion aperture through which a tapered mandrel extends;   generating a first extrudate portion via the aperture, a first outer dimension of the first extrudate portion established by an inner dimension of the aperture, and a first inner dimension of the first extrudate portion established by an outer dimension of the mandrel; and   adjusting an axial position of the tapered mandrel, relative to a face of the die, during the providing the relative rotation and translation to generate a second extrudate portion having a second inner dimension that is different from the first inner dimension of the first extrudate portion to thereby vary a wall thickness between the first extrudate portion and the second extrudate portion.   
     
     
         2 . The method of  claim 1 , comprising:
 slicing the first and second extrudate portions, lengthwise; and   compressing at least part of each of the lengthwise-sliced first and second extrudate portions to reduce a difference in wall thickness therebetween.   
     
     
         3 . The method of  claim 2 , wherein the compressing is such that the sliced and compressed first and second extrudate portions differ from each other in at least one mechanical property. 
     
     
         4 . The method of  claim 3 , wherein the first and second extrudate portions differ in ductility by at least 15%. 
     
     
         5 . The method of  claim 4 , wherein the first and second extrudate portions differ in tensile strength by at least 25%. 
     
     
         6 . The method of  claim 1 , wherein the second extrudate portion has an outer dimension that is within 2% of an outer dimension of the first extrudate portion. 
     
     
         7 . The method of  claim 6 , wherein the second extrudate portion is deposited from the extrusion die including a tubing wall thickness with a value greater than 150% a wall tubing wall thickness of the first extrudate portion. 
     
     
         8 . The method of  claim 1 , wherein adjusting the axial position of the tapered mandrel includes retracting the tapered mandrel an opposite direction of the extrusion. 
     
     
         9 . The method of  claim 8 , comprising axially advancing, following the retracting of the tapered mandrel in an opposite direction of the extrusion, the tapered mandrel toward the extrusion die and in a direction of the extrusion, the axially advancing performed during the providing relative rotation and translation. 
     
     
         10 . The method of  claim 1 , comprising placing the tapered mandrel into the extrusion aperture, including axially advancing the tapered mandrel in a direction of the extrusion, such that a maximum outer diameter of the mandrel is disposed within the aperture and at the face of the extrusion die. 
     
     
         11 . A processed, shear-assisted extrusion product, comprising:
 at least a portion of unfurled, flattened extrudate tubing, the at least a portion including:
 a first axial region extruded from a first portion of a feedstock; and 
 a second axial region extruded from a second portion of a same feedstock; 
 wherein:
 the first and second axial regions have a substantially similar thickness; and 
 the first region comprises different physical properties than the second region. 
 
   
     
     
         12 . The extrusion product of  claim 11 , wherein the first and second axial regions differ in ductility by at least 15%. 
     
     
         13 . The extrusion product of  claim 11 , wherein the first and second axial regions differ in tensile strength by at least 25%. 
     
     
         14 . A system for solid phase processing (SPP) of a billet or other feedstock, the system comprising:
 an extrusion die including:
 a die face configured to have relative rotational motion relative to a feedstock material; and 
 a die orifice arranged to establish an outer dimension of an extrudate tubing; 
   a first driver configured to apply an axial extrusion force to drive the feedstock material and the die face together, during the relative rotational motion;   a tapered mandrel extending through the die orifice and slidingly translatable therethrough, the tapered mandrel configured to establish an inner dimension of an extrudate tubing; and   a system controller configured to establish or adjust the rotation of the die face relative to the feedstock material and contemporaneously establish or adjust an axial position of the tapered mandrel, relative to a face of the die modulate an extrusion aperture defined between the die orifice and the tapered mandrel to thereby vary a wall thickness between a first extrudate portion and a second extrudate portion.   
     
     
         15 . The system of  claim 14 , comprising an extrudate compressor configured to compress at least part of the first and second extrudate portions to reduce a difference in wall thickness therebetween. 
     
     
         16 . The system of  claim 15 , wherein the extrudate compressor includes a rolling mill. 
     
     
         17 . The system of  claim 14 , wherein the system is configured to extrude the first and second extrudate portions such that the second extrudate portion has an outer dimension that is within 2% of an outer dimension of the first extrudate portion. 
     
     
         18 . The system of  claim 17 , wherein the system is configured to extrude the first and second extrudate portions such that the second extrudate portion is deposited from the extrusion die including a tubing wall thickness with a value greater than 150% a wall tubing wall thickness of the first extrudate portion. 
     
     
         19 . The system of  claim 14 , wherein the system controller is configured to retract the tapered mandrel an opposite direction of the extrusion. 
     
     
         20 . The system of  claim 19 , wherein the system controller is configured to axially advance, following the retracting of the tapered mandrel in an opposite direction of the extrusion, the tapered mandrel toward the extrusion die and in a direction of the extrusion.