WORK-HARDENED PSEUDOELASTIC GUIDE WIRES

摘要

The present invention provides a medical guide wire and a method of making same in which, an elongated solid core wire is made of NiTi alloy with a Ni content of about between 55.0 and 56.5 wt% and a reverse martensitic transformation start temperature (As) in the fully annealed state of not more than 55 DEG C. The wire has been thermomechanically processed to exhibit a work-hardened pseudoelasticity. After the last full annealing to regain workability, the wire is cold drawn with a significant amount of cold reduction of greater than 35%, but preferably greater than 38% The entire guide wire is subjected to the same heat treatment. The wire is formed into an elongated solid core. The heating step includes passing the wire through a tube furnace at substantially 280 DEG C to 370 DEG C. The entire guide wire is subjected to the same heat treating step. The guide wire has centerless grinding performed at an appropriate stage to provide a taper section and a distal section. There may be a coil attached around the distal section of the guide wire and which is made of a deformable material so that it may be deformed to a different radius or angle. Later, an outer jacket is provided which surrounds the core.