MEDICAL GUIDE WIRE USING WIDE STRAIN RANGE HIGH- ELASTICITY NI-TI ALLOY WIRE

摘要

PROBLEM TO BE SOLVED: To provide a medical guide wire formed by using an Ni-Ti alloy wire exhibiting high elasticity over a wide strain range. SOLUTION: At least either of the guide wire consisting of a main body side and a front end side is composed of an Ni-Ti alloy wire. The Ni-Ti alloy wire is subjected to mechanical straightening to a rectilinear shape without being subjected to a heat treatment after cold drawing. The wire does not exhibit stress induced martensite transformation and the stress-strain characteristics by tension tests are as follows: (1) The stress increases monotonously without having a yield point and inflection point up to the strain 4%; (2) the apparent modulus of elasticity at the strain 4% is >=3000 kgf/mm2; (3) the stress difference at the time of loading and at the time of load removal at the strain 2% when the strain is added and removed down to 4% is <=15 kgf/mm2 and (4) the residual strain when the wire is deformed to the strain 4% and the strain is removed is <=0.15%.