Plastic deformation can induce the austenite transformation to martensite in metastable austenitic stainless steels. To analyze this issue, a metastable austenitic stainless steel grade AISI 301 LN was studied in two different conditions, i.e. annealed and cold rolled. In the first case, the steel was fully austenitic, whereas after cold rolling a significant proportion of α’-martensite was present. High cycle fatigue tests at high stress ratios were carried out on specimens from both steel conditions. Several characterization techniques, including optical microscopy, X-ray diffraction and electron back scattered diffraction (EBSD), were used to detect and quantify the martensite. The results showed an increase on the fatigue life for the cold rolled specimens as compared to the annealed ones. This fact is related with the presence of martensite originated by cold rolling, which limited the amount of new martensite formed during fatigue tests.

Peer Reviewed