TWI

Friction stir welding (FSW) trials were carried out for thin HSLA-65 steel plate (6 mm thickness) to evaluate the potential benefits of using induction preheat. Other studies including tool design and multi-run welding are also evaluated as methods to demonstrate increased tool life and travel speed. Initial trials were aimed at measuring distortion associated with induction heating, independent of FSW at relatively low temperatures of 480 deg.C. Induction heating was then combined with FSW and changes were monitored in response load and weld surface morphology. Metallographic examination of samples was performed to show flow patterns associated with induction heating. Hardness measurements were also taken of samples welded with and without induction preheating. Further induction heating trials used ceramic insulation between the plate and the anvil. Effects of tool speed were investigated also using grade MS80 PCBN tools, at speeds from 5.1, 5.9 and 6.8 mm per second. Partial penetration welding with a short PCBN tool, with two overlapping runs, one from each side was also investigated. In addition to butt joint studies FSW was performed to evaluate the ability to create a T joint in the HSLA-56 steel.

8th International Symposium, 18-20 May 2010, Session 2A: Steel, Paper 01