Corrosion fatigue of a manganese-nitrogen stabilized austenitic stainless steel

Austenitic chromium-manganese-nitrogen stabilized stainless steels have been developed to replace chromium-nickel-nitrogen stainless steels in certain applications. in comparison, chromium-manganese-nitrogen steels have improved mechanical properties and acceptable corrosion resistance in hot, high chloride containing media. In this paper, corrosion fatigue investigations of a solution annealed and for practice more relevant 14% cold worked high alloyed chromium-manganese-nitrogen steel have been done. Inert glycerine was used as reference media and 62% calcium chloride solution as corrosive media, both aerated at a temperature of 120 degrees C. The stress ratio between upper and lower stress levels was 0.05 (tension-tension loading) to avoid the destruction of the fracture surfaces. As testing frequency for the dynamic experiments, 20 Hz was chosen considering possible application areas. Maximum stress versus number of cycles curves were recorded and representative specimens were investigated in a scanning electron microscope. in addition, electrochemical tests, exposure tests and constant load tests were done. This paper shows results on the corrosion fatigue of a manganese-nitrogen stabilized austenitic steel in a hot high chloride containing salt solution and helps to get a better understanding of occurring failure mechanisms.