This master's thesis investigates plasma arc welding and activated plasma arc welding of a single square groove butt joint in 6 mm thick AISI 304 stainless steel plates, without edge preparation. Welding was performed at a travel speed of 15 cm/min. The weld cap was completed using the TIG welding process, and the welding parameters were recorded throughout the experiments. The study analyzes the effect of using an activating flux during plasma arc welding on the reduction of welding current intensity, weld geometry and dimensions, weld microstructure and mechanical properties. Mechanical testing was performed on both, the base material and welded specimens and included tensile, bending, and Charpy impact toughness tests. Plasma arc welding and activated plasma arc welding are more demanding to perform than TIG welding, due to the higher number of influential process parameters. The welding current, required to achieve full penetration of the material, was reduced when activating flux was applied. The welds exhibited a narrow heat-affected zone due to the higher welding speed. The weld microstructure was dendritic and fine-grained. Compared to the base material, the welded specimens showed lower elongation and impact toughness, while their average tensile strength and yield strength were higher.
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