In general, the reduction in area is applied for the characterization of the hot working ability of Duplex steels. Up to now, the determination of this parameter at Böhler Edelstahl GmbH & Co KG was carried out by hot tensile tests in an external laboratory. An adjustment of the existing unit for hot forming simulation Gleeble 3800 TM makes it possible to do in - house tests. The theoretical part of the present study describes the microstructure formation and the precipitation behavior of Duplex steels and provides a summary of essential parameters influencing the hot formability. The effect of the relation between austenite and ferrite is shown in principle by means of three Super-Duplex steels 1.4501 (X2CrNiMoCuWN25-7-4), 1.4507 (X2CrNiMoCuN25-6-3) and the modified 1.4501 (Böhler A912). Furthermore, the investigation of the microstructure evaluates the influence of non - metallic inclusions, precipitations and intermetallic phases on the hot working behavior of these materials.