Multi-section faced shoulderless retractable variable penetration friction stir welding tool

Abstract

A method of friction stir welding and a non-consumable multi-section faced retractable shoulderless variable penetration friction stir welding tool. The tool includes a substantially cylindrical body portion, a head portion, and a tip section, each integral to the tool. The body portion has a longitudinal axis about which it is rotable, a diameter, a sidewall substantially parallel to the longitudinal axis, a proximal end, and a distal end. The head portion is located at the distal end of the body portion. The head portion includes a multi-section face, having a first face section and a second face section, that converges to the tip section. The tool is retractable, reduces overheating, improves weld quality by reducing internal voids and lack of fusion, and facilitates variable penetration welds.

1 . A non-consumable multi-section faced retractable shoulderless variable penetration friction stir welding tool for use in joining a first workpiece, having a first thickness, and a second workpiece, having a second thickness, by friction stir welding, comprising:
 a substantially cylindrical body portion, a head portion, and a tip section, each integral to the tool, the body portion having a longitudinal axis about which it is rotable, a diameter, a sidewall substantially parallel to the longitudinal axis, a proximal end, and a distal end; and   the head portion located at the distal end of the body portion having a base with a diameter substantially equal to the diameter of the body portion forming a transition between the body portion and the head portion, and the head portion having a multi-section face with a first face section nearest the body portion and a second face section nearest the tip section wherein the multi-section face converges to the tip section having a diameter and a center wherein the center is located substantially on the longitudinal axis, a height from the distal-most portion of the tip section to the base along the longitudinal axis and the first face section having a first section horizontal projection component with a magnitude of less than fifteen percent of the body portion diameter and the first face section converges at a first face opening angle to the second face section thereby forming a substantially frustoconical shape.   
   
   
       2 . The tool of  claim 1 , wherein the second face section forms a substantially frustoconical shape with the second face section converging to the tip section at a second face opening angle between approximately 70 degrees and approximately 160 degrees. 
   
   
       3 . The tool of  claim 1 , wherein the first face opening angle is between approximately 40 degrees and approximately 120 degrees. 
   
   
       4 . The tool of  claim 1 , wherein the first section horizontal projection component has a magnitude of less than eight percent of the body portion diameter. 
   
   
       5 . The tool of  claim 1 , wherein the first face section is curved having a radius of curvature of less than fifteen percent of the body portion diameter. 
   
   
       6 . The tool of  claim 1 , wherein the portion of the rotating non-consumable multi-section faced shoulderless variable penetration friction stir welding tool that is plunged into the joint is a portion of the head portion such that a portion of the first face section is within the first and second workpieces and a portion of the first face section is outside the first and second workpieces. 
   
   
       7 . A non-consumable multi-section faced retractable shoulderless variable penetration friction stir welding tool for use in joining a first workpiece, having a first thickness, and a second workpiece, having a second thickness, by friction stir welding, comprising:
 a substantially cylindrical body portion, a head portion, and a tip section, each integral to the tool, the body portion having a longitudinal axis about which it is rotable, a diameter, a sidewall substantially parallel to the longitudinal axis, a proximal end, and a distal end; and   the head portion located at the distal end of the body portion having a base with a diameter substantially equal to the diameter of the body portion forming a transition between the body portion and the head portion, and the head portion having a multi-section face with a first face section nearest the body portion and a second face section nearest the tip section wherein the multi-section face converges to the tip section having a diameter and a center wherein the center is located substantially on the longitudinal axis, a height from the distal-most portion of the tip section to the base along the longitudinal axis and the first face section having a first section horizontal projection component with a magnitude of less than approximately eight percent of the body portion diameter.   
   
   
       8 . The tool of  claim 7 , wherein the second face section forms a substantially frustoconical shape with the second face section converging to the tip section at a second face opening angle between approximately 70 degrees and approximately 160 degrees. 
   
   
       9 . The tool of  claim 7 , wherein the first face section forms a substantially frustoconical shape with the first face section converging to the second face section at a first face opening angle. 
   
   
       10 . The tool of  claim 9 , wherein the first face opening angle is between approximately 40 degrees and approximately 120 degrees. 
   
   
       11 . The tool of  claim 7 , wherein the first face section is substantially orthogonal to the longitudinal axis. 
   
   
       12 . The tool of  claim 11 , wherein the first section horizontal projection component has a magnitude of less than approximately five percent of the body portion diameter. 
   
   
       13 . The tool of  claim 7 , wherein the first face section is curved. 
   
   
       14 . The tool of  claim 7 , wherein the portion of the rotating non-consumable multi-section faced shoulderless variable penetration friction stir welding tool that is plunged into the joint is a portion of the head portion such that a portion of the first face section is within the first and second workpieces and a portion of the first face section is outside the first and second workpieces.