This presentation will describe recent developments at TWI on the joining of Ti alloys using the novel Stationary Shoulder Friction Stir Welding (SSFSW) method. In SSFSW, heat is generated by a rotating tool probe, which is separate from a non-rotating tool shoulder component. The tool shoulder component provides containment to the weld area, but adds no heat to the top surface of the joint.

The SSFSW approach is designed to provide uniform heat input throughout the thickness of the welded material, allowing very stable, high quality, solid-phase joints to be made in Ti alloys. SSFSW has been shown to be a valuable new development of the FSW process, which is particularly suitable for a range of high temperature, low thermal conductivity, materials.

This presentation will review the recent development of the SSFSW technique, and its application to Ti alloys. Examples will be shown of the specialist systems that have been produced to carry out this process, and possible applications will be illustrated via a range of demonstration weld samples.

The development and exploitation of SSFSW offers the potential for a reliable solid-phase welding method for Ti components. Possible applications of this technique include: joining of Ti components, additive manufacture of Ti prototypes and/or machining pre-forms, selective local reprocessing of Ti parts, and repair of damaged areas in Ti structures.

In summary this presentation will provide an overview of recent development work on the FSW of Ti alloys, including examples of demonstration parts produced using the new SSFSW approach.