Resistance Spot Welding of 7075 Aluminium Alloy
New generations of high strength aluminium alloys are widely used in automotive industry. 7075 (AlZn5.5MgCu) is an aluminium alloy with zinc as the primary alloying element (according to EN 485-2 standard). The 7075 has outstanding strength properties, but the elongation is limited between 5 and 11%. This means an obstacle when this alloy is aimed to use in car body elements. The goal of the present research work is to analyse the weldability of this alloy through resistance spot welding (RSW) tests. Experiments are performed on 1 mm thick 7075 sheets in T6 condition with different surface pre-treatment methods and the weld lobe was determined for constant electrode force. A Tecna 8007 RSW equipment with a TE 550 control unit was applied, which has been recently developed with a tool for the application of post pressing force. The spot welded joints were examined by macro testing, tensile shear and hardness tests. The properties of RSW joint from 7075 were compared with the 6082 alloy.
KeywordsHigh strength aluminium 7075 Resistance spot welding (RSW) Tensile-shear test Weld lobe
The authors thank the European Commission for their support on the H2020 project “Low Cost Materials Processing Technologies for Mass Production of Lightweight Vehicles (LoCoMaTech)”, Grant No: H2020-NMBP-GV-2016 (723517).
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