Microstructural Observation of Carbon Manganese Steel During Underwater welding

Welding is a principal industrial process which is used for joining metal. Welding is a versatile method which is widely used because of its high productivity and low cost in the industries. Due to its abundant source, carbon steel is widely used in the industries.
Carbon steel is also widely used in the industries due to its low cost, and excellent mechanical properties. The aim of this study is to identify the formation of weld bead and also weld defects comparing carbon manganese steel welded on air and carbon manganese steel welded underwater using the Shielded Metal Arc Welding (SMAW) process. Carbon Manganese steel is the type of carbon steel used in this research. The welding electrode used in this research is the Barracuda wet underwater welding electrode. The welding parameters for the welding process are 180 Ampere welding current and 37.41 mm/s welding speed. The base metal measurement is 150 mm x 50 mm × 6 mm. For characterization process, an optical microscope was used to study the weld bead formation, porosity formation in weld metal, the formation of other weld defects, and the heat affected zone. On air welding shows a larger weld bead size, penetration depth, and reinforcement height. Underwater welds show to have more porosity than on air welds. The heat affected zone for on air weld metal is larger than underwater welded metal.
Keywords: SMAW, Porosity, Weld defects, HAZ