Guide wire with core having welded wire segments

Abstract

An intravascular guide wire having two core materials joined together without the use of a connector tube or sleeve, the core materials being stainless steel and psuedoelastic metal alloy, nitinol. The core materials are joined to each other through an intermediate transition piece made essentially of nickel, which is welded on either side to the two core materials. In a multi-segment intravascular guide wire, discrete, high modulus and medium modulus core portions of different materials are welded to a shapeable, low modulus distal core portion made of a third material having a flattened, shapeable section at a most distal end that is not welded to but made from the distal core portion, so the flattened, shapeable section can be deformed to create a steerable tip. Processes such as simultaneous resistance and friction welding can be used to join the core portions.

1 - 20 . (canceled) 
     
     
         21 . A method for joining a multi-segment core intravascular guide wire, comprising:
 providing a guide wire core comprised of a distal section made from cold-worked linear-elastic nitinol, an intermediate section made from superelastic nitinol, and a proximal section made from stainless steel;   axially aligning the discrete core sections;   rotating one section at a fixed speed;   butting one of the sections to the rotating section while applying a fixed axial force creating upset material to create joined core sections with a butt joint;   applying resistance weld energy;   terminating resistance weld energy; and   abruptly stopping rotational speed to zero.   
     
     
         22 . The method of  claim 21 , wherein the butt joint contains no melted and re-solidified material. 
     
     
         23 . The method of  claim 21 , wherein the method further comprises removing the upset material from the periphery of the butt joint of the joined core sections. 
     
     
         24 . The method of  claim 23 , wherein removing the upset material from the periphery of the butt joint includes grinding the upset material. 
     
     
         25 . The method of  claim 23 , wherein removing the upset material from the periphery of the butt joint includes passing the joined core sections through a die to shear away the upset material. 
     
     
         26 . The method of  claim 21 , wherein the resistance weld energy is applied only when the one section is being rotated.