Influence of nitrogen alloying on dynamic strain ageing regimes in low cycle fatigue of AISI 316LN stainless steel

摘要

The effect of nitrogen alloying (0.078% to 0.22%) in 316 LN stainless steel has been investigated for its Low Cycle Fatigue properties in the temperature range 300 to 873 K. The effect of dynamic strain ageing has been evaluated as a function of nitrogen content, temperature, strain amplitude and strain rate. The temperature range of operation of DSA has been found to be a strong function of the above parameters. Increase in nitrogen content shifted the range of operation of DSA to higher temperatures. For temperatures > 673 K, fatigue life is found to be maximum for a nitrogen content of 0.14 wt%, while it is found to saturate or increase with increasing nitrogen content at temneratures < 673 K.