Cyclic Oxidation Behaviour of Heat Resistance Cast Steel

The oxidation behaviour of niobium and titanium enriched, heat resistant cast steel 30Ni-18Cr has been evaluated under cyclic conditions. Cyclic testing was carried out in the air, at temperature of 800, 900 and 1000°C. The alloys underwent oxidation in 5 cycle tests. Characterization of the corrosion products was performed using SEM and X-ray examinations. The cross section and the surface of tested alloys were examined. It has been found that the oxidation resistance of cast steel 30Ni-18Cr in thermal cycling is higher when niobium or especially titanium are added to chemical composition of the alloy. The formation of scale rich in titanium oxides TiO2 was contributed to better oxidation behaviour.