TWI

The application of suitable friction stir welding (FSW) tools and procedures to common structural geometries in industry, with emphasis of FSW of hard metals including steel, titanium and nickel based alloys in butt, T-joint, corner joint and circumferential geometries is discussed. A variable penetration tool (VPT) design developed by EWI is referenced as an effective geometry for the FSW of hard materials. Aluminium structures including a hull with challenging T and corner joints, and the front quarter of a combat vehicle, joined primarily using FSW as well as GMAW and TIG welding, are illustrated. Key considerations highlighted during the production of these components include the fixturing and controlling the penetration of the tool and the finish surface of the part. Examples of titanium alloy (Ti, 6%Al, 4%V) structures include a stabiliser arm for a gun cradle, and a prototype combat vehicle hull which required hybrid laser arc welding as well as GMAW and FSW. FSW in additive manufacturing of titanium alloys into discs is also discussed and developments of a bobbin tool for welding a 6.35 mm titanium alloy plate are outlined. Steel examples include two flat X-70 HSS plates joined using FSW to simulate the construction of ship panelling and girth welding of a X-80 HSS pipe. Preliminary work on FSW of Inconel 718 is outlined for 0.125 inch plate to demonstrate the feasibility of using the DuraStir line of FSW tools.

8th International Symposium, 18-20 May 2010, Session 3B: Titanium, Paper 01