LOW-TEMPERATURE FATIGUE OF 316L AND 316LN AUSTENITIC STAINLESS-STEELS

This article is concerned with the cyclic properties of 316L-type austenitic stainless at 300 and 77 K. The role of nitrogen alloying and of the temperature decrease is examined during low-cycle fatigue (LCF) and fatigue crack propagation. Fatigue resistance is enhanced by the addition of nitrogen in steel at both test temperatures. The results are discussed on the basis of microstructural observations. Planar slip of dislocations is found in the nitrogen-containing steel and is favored by a decrease in test temperature. To some extent, the influence of interstitial nitrogen on the fatigue properties is related to its role in stabilizing austenite observed during cooling as well as during straining.