In super duplex stainless steels (SDSS) the properties of both phases, ferrite and austenite, depend strongly on their chemical composition. The main alloying elements chromium, molybdenum, nickel and nitrogen are not equally distributed in ferrite and austenite. Chromium and molybdenum are enriched in the ferrite phase, whereas nickel and nitrogen are enriched in the austenite. The partitioning of these elements influences the corrosion resistance of the alloy, since the resistance to localised corrosion is known to be controlled by the weaker phase. The resistance of the commercially available super duplex stainless steel SAF 2507 to localised corrosion can be enhanced by increasing the alloying elements nitrogen and molybdenum. To increase the nitrogen solubility some manganese is added. The aim of the present investigation was to check the effect of an increased nitrogen and molybdenum content with respect to precipitation behaviour, austenite/ferrite volume fractions and corrosion resistance. A solution annealing temperature is determined, where minimal precipitation occurs, and equal corrosion resistance of both phases leads to optimised corrosion. The experimental results were step by step compared with thermodynamical calculations. A guideline for further alloy development is given.