Patent ID: 8052620

Claim:
A guide wire comprising: a distal core member made of a ferrous alloy which has shape memory properties and superelasticity, includes two phases having a γ phase and a γ′ phase, and has a difference of 100° C. or less between a reverse transformation finish temperature and a martensitic transformation start temperature in a thermal hysteresis of martensitic transformation and reverse transformation, the ferrous alloy including from 30 to 50% by mass of iron; an abundance of a specific crystal orientation in a working direction of a worked portion for the ferrous alloy is at least 2.0; a proximal core member which is made of an iron-containing alloy and has a higher modulus of elasticity than the distal core member; and wherein the distal core member and the proximal core member are joined together by welding to form a core of the guide wire; and wherein the guide wire is configured for insertion into a living body lumen in order to reach a target site.