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Abstract
Stainless steels are having very important role in the industries, because of its good mechanical properties, better corrosion resistance and good weld ability. Samples of 304 austenitic stainless steel welds which were fabricated by TIG welding, are subjected to the sensitization heat treatment in the Muffle furnace at 690°C for 4 hours followed by cooling in furnace. Cryogenic treatment is done by dipping the weld bead into liquid nitrogen at -193°C. The soaking time and the temperature effects the mechanical properties, due to these significant changes appear in the mechanical properties of the austenitic stainless steel. Sensitization heat treatment shows the 4.6% increase in impact energy and considerable 6% decrease in hardness after treatment along with ditch type of structure which is observed after oxalic acid etching and in microstructural studies annealing twin are observed. On the other side, Cryogenic treatment results 22.14% increase in hardness of sensitized sample as well as 29.53% increases in non-sensitized sample. However, impact energy 22.3% is decreased in sensitized and non-sensitized sample is decreased by 27.7%. Isolated ferrite pools are observed on sensitized cryogenic treated sample and dual type structure