W. M. Thomas, C. Wiesner, TWI, Cambridge, United Kingdom
In welded components the toughness of the joint is of great concern. Imperfections, especially surface breaking, can exist in the root region which can affect structural integrity. This paper describes results of impact testing friction stir welded joints containing root imperfections. The paper also looks at recent advances made in friction stir welding of steel using refractory metal tools, and describing a method of securing two different types of refractory materials to provide a composite FSW tool. The use of composite tools enables different ‘coupling' relationships to be made between the shoulder and the workpiece and the probe and the workpiece. Furthermore, this paper describes some of the feasibility work that has been carried out to develop self-reacting, (bobbin) friction stir welding of 25 mm thick aluminium alloy material.
Summary: In welded components the toughness of the joint is of great concern. Imperfections, especially surface breaking, can exist in the root region which can affect structural integrity
