Friction Stir Welding of Thick Section Aluminium Alloys—New Techniques

Abstract

There are many applications for which joining of thick section aluminium components is required; these include aircraft wing spars, liquefied natural gas tanks, armour plate, and railway headstocks. Using conventional fusion welding techniques can be challenging. Recent innovations at TWI, using the unique twin headed capabilities of the PowerstirTM friction stir welding (FSW) machine, have demonstrated several techniques that have the potential to minimise production cycle times, making joining of thick section aluminium alloys both technically and commercially advantageous. This paper describes these techniques and the work undertaken at TWI to develop them. Process benefits and weld properties are discussed highlighting the potential benefits including reduce component processing times through quicker welding and minimal part handling; improve weld quality through use of reduced and uniform heat input and increase tool life leading to reduced tooling costs.