Investigation on the effect of auxiliary vibrations on microstructure and mechanical properties of SMAW butt welded joints

Abstract

In this study, an attempt has been made to investigate the effect of inducing auxiliary vibration into the weld pool during welding and aimed to understand the fundamental role of vibration in controlling the weld pool microstructure and mechanical properties. A vibratory set-up has been used to transfer the mechanical vibration in the molten weld pool during shielded metal arc welding (SMAW) process. Vibratory welding is performed on 6 mm thick mild steel plate with various material combinations using bead on plate technique. A comparative investigation between conventional welding and vibratory welding technique is conducted. The mechanical strength is evaluated using micro-hardness and transverse tensile tests. The result shows the enhancement in yield strength by 28%, 25% and 48% for the combination of WB_MS/MS, WB_SS/MS and WB_ST/MS, respectively. The metallographical studies show that induced vibration during welding increased the nucleation rate and steeper thermal gradients across the heat affected zone (HAZ) is found. Comparatively finer grain microstructures are observed in the vibratory welding condition.