Abstract:This research presents observation of the microstructure of 1018 mild steel in the heat affected zone (HAZ) region. For SAW process various parameters are chosen such as current, voltage and welding speed. The welding experiments were conducted as per the Taguchi L9 method. The samples of 1018 MS were welded by submerged arc welding (SAW), followed by sample preparation and observation under Nikon microscope. Sample was prepared by cutting, mounting, polishing and etching method. It was observed that the microstructure of the centre of weld zone is completely different from the heat-affected zone. The few defects such as porosity, inclusion due to slag and the variation in microstructure due to temperature difference and cooling rate are observed through microscopic analysis.