Environmentally-Assisted Cracking of Type 316L Austenitic Stainless Steel in Low Pressure Hydrogen Steam Environments

A low pressure, superheated hydrogen-steam system has been used to accelerate the oxidation kinetics while keeping the electrochemical conditions similar to those of the primary water in a pressurized water reactor. The initiation has been investigated using a Constant Extension Rate Tensile (CERT) test. Tests were performed on flat tapered specimens made from Type 316L austenitic stainless steel with strain rates of 2x10(-6) and 2x10(-8) ms(-1) at room temperature and at an elevated temperature of 350 degrees C. R = 1/6 was chosen as a more oxidizing environment and R = 6 was selected as a more reducing environment, where the parameter R represents the ratio between the oxygen partial pressure at the Ni/NiO transition and the oxygen partial pressure. Different exposures (1 day and 5 days) prior to loading were investigated post-test evaluation by scanning electron microscopy. (C) 2019 The Authors. Published by Elsevier B.V.