Assembling of aluminum components in automotive: a comparison between Resistance Spot Welding and Static Shoulder friction Stir Welding
By Antonino Squillace (University of Naples Federico II), Filomena Impero (University of Naples Federico II), Fabio Scherillo (University of Naples Federico II), Carlo Verde (Proma s.p.a.), Renzo Casarin (FPT Industrie SpA), Renzo Vezzaro (FPT Industrie SpA), Ciro Sinagra (Laminazione Sottile s.p.a.)

In this work a comparison is proposed between two welding techniques suitable in automotive: the conventional Resistance Spot Welding (RSW) and the innovative Static Shoulder Friction Stir Welding (SSFSW).
Two sheets of AA 5182-O, with a thickness of 2 mm each, were lap welded using the two techniques. Joints were characterized in terms of microstructure, Vickers microhardness and surface microgeometry.
Pores and cracks are evident in the whole cross section of the RSW joint; the SSFSW joint shows a thin continuous hook defect. Through microscopy observations the transition from weld zone to partially melted zone up to heat affected zone and then parent material is evident for RSW joints, while the intermetallic flux shows distinctly the advancing side and retreating side for SSFSW joints. Finally, the latter joint showed a microstructure with considerably smaller and homogeneous grains than the former and microhardness values very constant along the whole weld bead