Effect of Welding Parameters on Mechanical Properties of Friction Stir Welded Aluminum Alloy and Coated Steel Sheet Lap Joint

摘要

Friction Stir welding has been attempted to evaluate joint strength of lap joint between aluminium sheet (AA6063) and zinc coated steel (HIF-GA) sheet under different combination of rotational speed and traverse speed. The shear strength decreases significantly when rotational speed increases from 700 rpm to 1500 rpm at a traverse speed of 30 mm/min. At traverse speed 50 mm/min, increasing rotational speed from 700 rpm to 1500 rpm, shear strength remains more or less same. However, at a traverse speed of 100 mm/min, the shear strength increases significantly with increasing rotational speed from 700 rpm to 1500 rpm. The different process parameters have been correlated with fracture load through heat input generated from recorded torque curve during welding. Essentially, higher fracture load of the lap joint is obtained within a certain range of heat input i.e1.26 to 2.1 KJ/mm. The results have been correlated with the microstructural characteristics at the bond interface using nanohardness test, EDS, EPMA and XRD. The results show little diffusion at the interface to form the intermetallic compound probably indicating that mechanical anchoring takes predominating role towards lap joint of Al and coated steel. Furthermore, force and torque data can be utilized as weld quality check.