The dependence of fatigue crack growth on hydrogen in warm-rolled 316 austenitic stainless steel

摘要

The fatigue crack growth rate of warm-rolled AISI 316 austenitic stainless steel was investigated by controlling rolling strain and temperature in argon and hydrogen gas atmospheres. The fatigue crack growth rates of warm-rolled 316 specimens tested in hydrogen decreased with increasing rolling temperature, especially 400 degrees C. By controlling the deformation temperature and strain, the influences of microstructure (including dislocation structure, deformation twins and alpha' martensite) and its evolution on hydrogen induced degradation of mechanical properties were separately discussed. Deformation twins deceased and dislocations became more uniform with the increase in rolling temperature, inhibiting the formation of dynamic alpha' martensite during the crack propagation. In the cold-rolled 316 specimens, deformation twins accelerated hydrogen-induced crack growth due to the alpha' martensitic transformation at the crack tip. In the warm-rolled specimens, the formation of alpha' martensite around the crack tip was completely inhibited, which greatly reduced the fatigue crack growth rate in hydrogen atmosphere. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.