TWI

An apparatus was developed to analyse the contact condition between the rotating tool and the workpiece during friction stir welding, and empirical tests were performed to determine the friction conditions (static, dynamic and the transition from one to the other) and the thermal contact resistance between two different cylindrical rotating samples at various temperatures (ambient to 1000 deg.C) and contact pressures (7-12 MPa). An inverse analytical method combined with an experimental rig was employed to determine the friction mechanism evolution for various pairs of materials and test conditions. The material combinations studied were steel and AA6063 + B₄C, AA6061-T6 and AA6063 + B₄C, and steel and AA6061-T6. The influence of relative displacement between surfaces on friction coefficient is discussed.

7th International Symposium, 20-22 May 2008, Poster Session, Paper 09