Mechanical properties of plasma arc welded AISI304LN austenitic stainless steel at various temperatures

AISI 304 grade austenitic stainless steels are widely used in a wide variety of fields such as chemical, automobile, food industries, etc. due to their good mechanical properties and corrosion resistivity. In this study, AISI 304LN austenitic stainless-steel couples were joined with plasma arc welding. The effect of temperature on the mechanical properties, formability and fracture morphologies of joints was evaluated. For this purpose, tensile testing of the joints was carried out in the temperature range of -50 degrees C, and 25 degrees C-850 degrees C. Thus, the ultimate tensile strength, (UTS), yield strength, (YS) and elongation (EL%) amounts of welded joints were determined. The fracture morphologies of the tensile test samples were examined. It was observed that the rupture (except 850 degrees C) occurred from the weld metal. The highest formability was obtained in the samples tested at 850 degrees C. In addition, the existence range of dynamic strain aging (DSA) of the plasma arc welded samples was also investigated. The unsteady plastic flow between the yield and the ultimate tensile of the sample subjected to the tensile test at 250-550 degrees C are evaluated as signs of DSA.