Solid state processing of hand-held knife blades to improve blade performance

Abstract

A system and method for friction stir processing of a hand-held cutting edge, wherein friction stir processing techniques are used to modify the properties of the hand-held cutting edge to obtain superior edge retention and superior resistance to chipping of the hand-held cutting edge.

1 - 20 . (canceled) 
     
     
         21 . A method for creating a metallic blade for a hand-held knife, said method comprising:
 providing a high melting temperature metallic workpiece that is to be formed into a hand-held knife blade;   providing a friction stir processing tool that includes a higher melting temperature material than the workpiece on a portion thereof; and   friction stir processing at least a portion of the workpiece using the tool to thereby modify characteristics thereof to form a friction stir processed region of the workpiece; and   forming the blade of the hand-held knife blade from the workpiece, such that a cutting edge of the blade is formed in the friction stir processed region such that the cutting edge comprises the friction stir processed material and will resist fracturing after repeated impacts thereon while also retaining a shaving sharpness, and wherein the cutting edge will retain these characteristics longer than a cutting edge on a conventional blade unmodified by friction stir processing which exhibits an inverse relationship between impact resistance and toughness in comparison to wear resistance and hardness.   
     
     
         22 . The method as defined in  claim 21 , wherein forming the blade of the hand-held knife blade from the workpiece comprises forming the blade such that a portion of the blade other than the cutting edge is formed in a portion of the workpiece outside the friction stir processed region of the workpiece. 
     
     
         23 . The method as defined in  claim 21 , wherein forming the blade of the hand-held knife blade from the workpiece comprises grinding the workpiece to form a blade after friction stir processing. 
     
     
         24 . The method as defined in  claim 21 , wherein the method further comprises the step of causing a substantially solid state transformation without passing through a liquid state of the base material. 
     
     
         25 . The method as defined in  claim 21 , wherein providing the high melting temperature base material includes selecting the high melting temperature base material from the group of high melting temperature materials including ferrous alloys, non-ferrous materials, superalloys, titanium, cobalt alloys typically used for hard-facing, and air hardened or high speed steels. 
     
     
         26 . The method of  claim 21 , wherein selecting the high melting temperature base material from the group of high melting temperature materials including ferrous alloys, non-ferrous materials, superalloys, titanium, cobalt alloys typically used for hard-facing, and air hardened or high speed steels comprises selecting ATS 34 steel or D2 steel. 
     
     
         27 . The method as defined in  claim 21 , wherein the method further comprises the step of synthesizing a new material from solid state processing of the workpiece, wherein the new material has characteristics that are advantageous to a hand-held knife blade. 
     
     
         28 . The method as defined in  claim 21 , wherein friction stir processing at least a portion of the workpiece using the tool to thereby modify characteristics thereof to form a friction stir processed region of the workpiece further comprises providing an additive material; and
 friction stir mixing the additive material into the workpiece to thereby modify at least one characteristic of the workpiece base material.   
     
     
         29 . The method as defined in  claim 28 , wherein providing an additive material comprises providing diamond particles, carbide or stainless steel. 
     
     
         30 . The method as defined in  claim 21 , wherein the method further comprises the step of modifying a microstructure of the workpiece. 
     
     
         31 . The method as defined in  claim 30 , wherein the method further comprises the step of modifying a macrostructure of the workpiece. 
     
     
         32 . The method as defined in  claim 31 , wherein modifying the microstructure includes increasing toughness of the base material. 
     
     
         33 . The method as defined in  claim 31 , wherein modifying the microstructure includes increasing or decreasing hardness of the base material. 
     
     
         34 . The method as defined in  claim 31 , wherein modifying the microstructure includes increasing or decreasing strength of the workpiece. 
     
     
         35 . The method as defined in  claim 31 , wherein modifying the microstructure includes friction stir processing the workpiece to thereby obtain superior edge retention on the hand-held knife blade that is formed therefrom. 
     
     
         36 . The method as defined in  claim 31 , wherein modifying the microstructure includes friction stir processing the workpiece to thereby obtain superior resistance to chipping on the hand-held knife blade that is formed therefrom. 
     
     
         37 . The method as defined in  claim 21 , wherein providing the friction stir processing tool further includes the step of providing the friction stir processing tool having a shank, a shoulder and a pin. 
     
     
         38 . The method as defined in  claim 37 , wherein friction stir processing at least a portion of the workpiece using the tool to thereby modify characteristics thereof to form a friction stir processed region of the workpiece comprises friction stir processing using a surface area of the pin to process at least a portion of the surface of the workpiece without plunging the pin into the workpiece. 
     
     
         39 . The method as defined in  claim 37 , wherein friction stir processing at least a portion of the workpiece using the tool to thereby modify characteristics thereof to form a friction stir processed region of the workpiece comprises friction stir processing with at least a portion of the pin plunged into the workpiece. 
     
     
         40 . The method as defined in  claim 21 , wherein providing the friction stir processing tool further comprises providing a friction stir processing tool having a shank and a shoulder, but having no pin. 
     
     
         41 . The method as defined in  claim 21 , wherein providing a friction stir processing tool that includes a higher melting temperature material than the workpiece on a portion thereof comprises providing a friction stir processing tool including a superabrasive material.