Influence of shielding gas flow rate on residual stresses in GMAW weld beads using L_CR waves

Welding is a widely used manufacturing process for permanently joining components. In fusion welding processes, high temperatures generate residual stresses (RS), which make the welded and thermally affected regions susceptible to failure. These stresses can superimpose on externally applied loads, making it crucial to determine RS to assess the forces borne by the component and prevent failures. Welding parameters, including the shielding gas flow rate (GFR), significantly influence the magnitude of RS. However, GFR has received limited attention in the literature regarding its overall impact. This study investigated the effect of GFR on RS in AWS ER70S-6 weld beads deposited on DIN EN 10025–2 S275JR steel plates using gas metal arc welding (GMAW) and critically refracted longitudinal waves (L_CR) for stress measurement. Weld beads were deposited with GFR values of 12, 15, and 20 l/min, while other parameters were kept constant. Longitudinal RS distribution profiles were obtained for each specimen. The results showed a significant impact of GFR on the RS profile, with the highest RS values observed at 15 l/min. These findings can aid the industry in selecting welding parameters that minimize RS, thus improving the prediction of structural integrity and failure of welded components. The study emphasizes the importance of evaluating the influence of welding parameters on RS in welded joints and shows the viability of employing L_CR technique to control the stresses in welds.