TWI

With regard to the dependence of welded joint properties on tool probe shape during friction stir welding (FSW) of dissimilar butt joints between aluminium and steel, an investigation was undertaken into the interface formation mechanism by conducting extensive microstructure observations. The materials studied were AA 6061 aluminium alloys and S45C carbon steel. FSW was performed at a rotational speed of 2000 rpm, welding speed of 500 mm/min and tool offset of 0.05 mm. Fracture surfaces of the weld interface after tensile testing were observed by SEM and energy dispersive spectroscopy in order to determine the adhesion state of the Al alloy on the steel surface. The hardness of aluminium, the thickness of the reaction layer and the maximum temperature during welding were measured along the weld interface in the depth direction. The influence of strong material flow on the weld interface and build-up edge around the probe is discussed.

10th International Symposium, 20-22 May 2014, Session 2B: Dissimilar I, Paper 03