Microstructurally and Mechanically Small Fatigue Crack Growth Behaviors of 316ln Stainless Steel in High-Temperature Pressurized Water

Abstract

Corrosion fatigue behaviors at different stages of microstructurally small crack (MSC) and mechanically small crack (MeSC) for 316LN stainless steel were investigated in high-temperature pressurized water by interrupted tests. An improved model about the proportion in total fatigue life and growth rate for the MSC and MeSC has been proposed. It is found that the proportion in total fatigue life for the MSC is lower and the crack growth rate is higher at a lower strain rate due to the high plastic deformation and dislocation density at grain boundary. Mechanism of crack growth in high-temperature pressurized water is discussed.

Keywords: stainless steel, SEM, TEM, Corrosion fatigue, high temperature corrosion