Effect of variation in oxygen concentration in static Pb-Bi eutectic on long-term corrosion performance of Al-alloyed austenitic steels at 500 degrees C

Aluminium-alloyed austenitic steels Fe-14Cr-2Mn-20Ni-0.5Cu-3Al and Fe-14Cr-5Mn-12M-3Cu-2.5Al were tested at 500 degrees C in static Pb-Bi eutectic for 10,000 h. The concentration of oxygen in the liquid metal was changed in a controlled way over the course of the test from similar to 10(-)(6) to similar to 10(-9) mass% which provided conditions for oxidation and dissolution, respectively. Both steels showed slight oxidation of surface. Steel with higher Ni content revealed also initiation of dissolution corrosion in the view of rare pit-type damages. The structural and compositional features of oxide films, sub-oxide zones and corrosion damages are discussed.