Sheet metal joining and distortion measurement of aluminium alloy and steel in cold wire GTAW process

Abstract

Abstract The dissimilar metal joining of aluminium alloy and steel sheets is an essential aspect of weight reduction in the automobile industry to increase the strength-to-weight ratio. The large gap in thermo-physical properties, development of intermetallic compounds (IMC) layer at the interface, and severe distortions make it challenging to produce an acceptable joint. In this study, the low heat input cold wire gas tungsten arc welding (GTAW) process is used to successfully join the 1 mm thick Al6061-T6 alloy sheet to galvannealed sheet using AC welding current. The weld-braze joint is developed in lap joint configuration, and various mechanical and physical aspects of the weld bead like weld thermal cycle, micro-hardness, IMC layer thickness, and severe surface and edge distortions are shown. This work's novelty is to report the accurate surface and edge distortions of the joined sheets by a novel technique using a 3-D scanner and CAD model of the workpiece. An overall successful joint is produced using a cold wire GTAW process and the 3-D scanner technique to measure surface and edge distortion found to be precise and accurate.