The effect of temperature on the SSRT behavior of austenitic stainless steels in SCW

The effects of temperature on the tensile properties and stress corrosion cracking (SCC) susceptibility of austenitic stainless steels AL-6XN, HR3C, and 316Ti in deaerated supercritical water were studied by performing slow-strain-rate tensile (SSRT) tests. The SSRT tests were carried out in deaerated supercritical water at temperatures of 550, 600, and 650 °C, a pressure of 25 MPa, and a strain rate of 9.26 × 10−7 s−1. The results show that AL-6XN exhibits the highest ultimate tensile strength and yield strength at each temperature, followed by HR3C and then 316Ti. Temperature has a large effect on the tensile properties of each material. The SCC susceptibility of AL-6XN increases with increasing temperature, whereas 316Ti exhibits the opposite trend. The fracture surfaces of all HR3C specimens and the 316Ti specimen tested at 550 °C are dominated by an intergranular fracture morphology, showing the high susceptibility of these specimens to SCC. Transgranular fracture was observed for specimens of AL-6XN strained at 600 and 650 °C.