Method for twisting a hollow metal tube

Abstract

A method for twisting a hollow metal tube includes the steps of (a) filling a predetermined section of the hollow metal tube between two opposite end sections of the hollow metal tube with a solid reinforcing member, and (b) holding and turning the two opposite end sections of the hollow metal tube relative to each other so as to twist the predetermined section of the hollow metal tube.

1 . A method for twisting a hollow metal tube, comprising the steps of: 
 a) filling a predetermined section of said hollow metal tube between two opposite end sections of said hollow metal tube with a solid reinforcing member, said solid reinforcing member filling said predetermined section of said hollow metal tube and further extending into said opposite end sections of said hollow metal tube; and    (b) holding and turning said two opposite end sections of said hollow metal tube relative to each other so as to twist said predetermined section of said hollow metal tube.    
     
     
         2 . The method as claimed in  claim 1 , further comprising a step (c) of removing said solid reinforcing member from said hollow metal tube after the step (b).  
     
     
         3 . The method as claimed in  claim 2 , wherein said solid reinforcing member is a material having a melting point lower than that of said hollow metal tube, the step (c) being conducted by melting said solid reinforcing member so as to enable said melted reinforcing member to flow out of said hollow metal tube.  
     
     
         4 . The method as claimed in  claim 3 , wherein said solid reinforcing member has a Vickers-hardness not less than 60.  
     
     
         5 . The method as claimed in  claim 3 , wherein said solid reinforcing member is a plastic material.  
     
     
         6 . The method as claimed in  claim 1 , further comprising a step of forging said predetermined section of said hollow metal tube and said solid reinforcing member between the step (a) and the step (b), wherein said solid reinforcing member and said hollow metal tube are made of the same material.  
     
     
         7 . The method as claimed in  claim 6 , wherein the cross-section of said predetermined section of said hollow metal tube is reduced after the step of forging.