Effect of Cr Limits on Microstructure and Mechanical Properties of P/M 316L Austenitic Steel

This study investigated the effect of the Cr limits on the microstructure and mechanical properties of 316L alloy. Five 316L alloys with varying Cr contents (16.8, 17.1, 17.3, 17.8 and 18.8 wt.%) were produced by the powder metallurgy (P/M) method. Microstructure studies and phase analysis were performed with a scanning electron microscope (SEM), optical microscopy (OM), and energy dispersive spectrometry (EDS). Tensile tests and hardness measurements were performed to evaluate the hardness, strength, and ductility of the alloys. The results showed that Cr addition affected the porosity and grain size of the alloys, as well as the formation of precipitates. The ultimate tensile strength reached a maximum at 17.3 wt.% Cr and then decreased with further Cr addition. Ductility decreased with increasing Cr under the influence of precipitates formed and changes in microstructure. On the other hand, the hardness increased with increasing Cr inversely to the ductility.