Shoke, Lerato SMutombo, KalendaOlubambi, PZondi, MC2026-08-282026-08-282026-02979-8-3507-6175-72169-8767https://doi.org/10.46254/GC03.20250279http://hdl.handle.net/10204/14916This study explores the influence of Submerged Arc Welding (SAW) parameters on the microstructural evolution, mechanical properties, and residual stresses in dissimilar welds of A516 Gr70 and A106 GrB high-strength carbon steels. Through a comprehensive experimental approach, this study delineates the direct relationship between the welding heat input, determined by the voltage, current, and speed, and its profound impact on the heat-affected zone (HAZ) size, microstructure, and mechanical properties, such as hardness and tensile strength. The investigation revealed that the optimal welding parameters play a critical role in controlling the bead geometry and HAZ size, which in tum significantly affect the mechanical integrity and performance of the welded joint. Notably, this study revealed that a higher heat input does not necessarily lead to a larger HAZ, challenging the conventional assumptions in welding practices. Furthermore, this study delves into the effects of post-weld heat treatment (PWHT) techniques, including normalizing, quenching, and annealing, on reversing the microstructural alterations induced by welding and restoring the initial mechanical properties of the base metals. Microstructural analyses employing stereo microscopy, optical microscopy, scanning electron microscopy, and X-ray diffraction techniques provide insight into the granular details of the morphological changes across different regions of the weld, highlighting the formation of martensitic lathes in the weld bead region and variations in the pearlite-ferrite matrix. Mechanical testing and hardness profiles substantiate these findings, illustrating the significant influence of cooling rates and heat treatment methods on the mechanical properties of the weldments. This study highlights the importance of controlled heat treatment in enhancing material performance, suggesting avenues for further research into parameter optimization, fatigue assessments, and advanced heat treatment techniques to refine welding processes for industrial applications.FulltextenSubmerged arc weldingDissimilar steelsA516 Gr70A106 GrBMicrostructuresMechanical propertiesPost­weld heat treatmentResidual stressesHeat-affected zoneConference Presentationn/a