An aircraft manufacturer was interested in linear friction welding as a way of lowering its buy/fly ratio, the difference between the cost of raw materials and turning them into operational flying components.
The objectives were to develop welding procedures for linear friction welding of AA7050-T7451 that had been subjected to a variety of thermo-mechanical processing operations, and to produce several dozen samples for testing and evaluation by the client.
TWI has three high-powered linear friction welding machines which are used to join titanium, stainless steel, aluminium, mild steel, and many nickel-based super alloys.
A series of trial welds was made specifically to determine the optimum welding parameters needed for high quality welds between sample blocks of AA7050 material provided by the client.
Five variables were considered: the friction and forge pressures, the burn-off, amplitude and frequency. With these values for 72 welds, TWI then tested their performance visually, metallographically and by tensile testing.
The results were; first, that high-integrity bonded interfaces were achieved in the experimental welds, and second, that the supplied material, which had been subjected to a 2% stretch before welding, required a higher forge force than unstrained material.
To learn more about TWI's friction welding capabilities in a variety of materials and applications, contact us.