Methods for counteracting rebounding effects during solid state resistance welding of dissimilar materials

摘要

The present disclosure is directed to methods for joining initially separate members of different metallic materials, e.g., as in joining segments of a multi-segment intravascular guide wire, as well as multi-segment intravascular guide wires so formed. Initially separate members are provided, which members comprise different metallic materials relative to one another (e.g., stainless steel and nitinol). The members are aligned with one another, and a first force is applied to the members while delivering electrical current through the members to solid state weld the separate members to one another. A follow up force that is greater than the first force is applied as solid-state deformation occurs and a weld nugget forms between the members. The weld nugget so formed is thinner and of a larger transverse cross-sectional area than would be produced without application of the follow up force.

主权项

1. A method for joining members of different metallic materials, the method comprising:
(a) providing multiple initially separate members, which members comprise different metallic materials wherein one member comprises nitinol and another member comprises stainless steel; (b) aligning the initially separate members so that the member comprising nitinol abuts the member comprising stainless steel to result in abutting aligned members; (c) applying a first axial baseline force to the abutting aligned members to press the abutting aligned members together, the abutting aligned members remaining rotationally stationary relative to one another, while delivering electrical current through the abutting aligned members to weld the abutting aligned members to one another; and (d) increasing the amount of applied axial force from a value of the first axial baseline force in (c) to an increased amount of applied axial force in (d) of 175,000 psi to 350,000 psi to join the members of different metallic materials to one another, the increased axial force being a follow up axial force that is greater than the first axial baseline force so as to produce a weld nugget that is thinner and of a larger transverse cross-sectional area than would be produced without application of the follow up axial force), a heat affected zone corresponding to the weld nugget having a thickness of less than about 0.2 mm.