Rust and acid resistant steels under complex loading

With corrosion fatigue investigations under different loadings (R 0,27, -1 and 10) and with inner pressure tests a duplex steel (1.4462) and a super austenitic steel (1.3974) are compared. The investigations were carried Out in 10% HNO3, artificial seawater according to DIN 50905 and in two very important liquids for application (artificial seawater according to DIN 50905 with H2S aerated and water with chloride, fluoride, bromide, iodide). For comparison the same tests under only mechanical loads were done in acid free oil. The results show that the super austenitic steel has an significantly higher resistance against corrosion fatigue as the duplex steel under one- and three dimensional loads up to 10(7) cycles. The proportion between the results in the corrosive liquids and the oil can be described by a factor. In artificial seawater factors between 0,67 and 0,92 and in 10% HNO3 between 0,67 and 0,83 were determined depending from the loading for the duplex With the super austenitic steel factors between 0,86 and 1 in artificial seawater and between 0,7 and 1,0 in 10% HNO3 were received.