Propagation of fissures by fatigue in metastable austenitic steels

Many works discuss martensitic transformation in austenitic stainless steels, and especially transformations induced by temperature or monotonic charges. Some studies have focused on the propagation of fissures by fatigue in metastable austenitic test pieces, which display reduced propagation speed of fissures when martensite is induced at the end of the fissure. However, controversy still persists with regard to the role of different parameters in the fatigue behavior of these steels. This work presents preliminary analysis results of fissure propagation by fatigue using test pieces obtained from 1 mm thick sheets of austenitic steel EN 1.4318 (AISI 301LN) with 17% Cr, 7% Ni, low C and alloyed with N. The tests were performed at R charge relations (relation between minimum and maximum charge) of 0.1, 0.3, 0.5 and 0.7. The results were analyzed applying the concepts of the two driving forces concept (cw)