Friction crush welding of aluminium, copper and steel sheetmetals with flanged edges

The implementation of friction crush welding (FCW) offers a versatile application in the welding of sheet metals. Three materials (EN AW 5754H22, DC01 and Cu-DHP) were analysed by applying the method with flanged edges. The additional material required to form the weld is provided by the flanged edges of the parent sheet metal. The joint is formed by the relative motion between a rotating disc, which is applied with a crushing force, and two sheet metal parts. The fundamental process variables and the requirements of the welding preparation are shown. Bond strengths, as a percentage of the yield strength of the parent material, of around 95% (DC01) 90% (EN AW 5754H22) and 62% (Cu-DHP) are achieved. Microstructural investigations reveal that a dynamic solid-state deformation and recrystallization of the additional flanged material results in a fine grain microstructure in the weld region. Reduced metallurgical changes along with minimized distortion and residual stresses in the parent material indicate low heat input. By creating a fine grain microstructure in the welding line, the friction crush welding method reveals great potential, especially for welding steel.