The microstructural evolution of Duplex Stainless Steel 2205 was investigated during Gas Tungsten Arc Welding with three types of protective atmosphere: (a) Ultra- high purity Ar, (b) 98% Ar- 2% N-2 mixture, and (c) 95% Ar- 5% N-2 mixture. The microstructural evolution was also characterized for three different heat inputs: low, medium, and high (0.5, 1.5, and 2.5 J mm (1). In terms of the effect of fatigue resistance and corrosion leading, the best performance was seen at values of 0.5 and 2.5 J mm (1), respectively. The decrease of the (Austenite) phase in Ar welding was associated with low performance in terms of resistance to fatigue and corrosion. On the other hand, the N2 content had a slight effect on the fatigue strength, tension, and impact resistance. A ductile fracture, which is desirable in this type of testing, was consistently observed. Protection with 2% and 5% N2 atmospheres and the control of heat input in the plasma process enabled a 45-fold lowering of the corrosion rate, increasing the life of the welded joint. (C) 2017 Elsevier Ltd. All rights reserved.