Continuous Observation of Stress Corrosion Cracking Propagation in SUS304 Stainless Steel by Using Differential Strain Transformer

The effect of the deformation-induced martensite (α′) on stress corrosion cracking (SCC) for SUS304 austenitic stainless steel was investigated by measurements of the time to failure of stress corrosion cracking for the specimens which contains (α′) martensite under a loaded stress of 0.2% proof stress and the creep strain during the SCC test in 1×10−2 kmol⁄m3HCl+35 mass%MgCl2 solution at 358 K.The main results obtained from the experiments are summarized as follows:(1) The time to failure of stress corrosion cracking of the specimens are decreased with increasing volume fraction of martensite below 57%. However, there is no effect on the time to failure of stress corrosion cracking of the specimens at the volume fraction of martensite higher than 57%.(2) The effects HCl concentration and loaded stress on the time to failure are little for the specimens martensite contained.(3) The crack propagation of stress corrosion of the specimens proceeds at two stages. The crack propagation rates at the first stage and the second stage increase with increasing volume fraction of martensite in SUS304 stainless steel under the same experimental condition. However, the rate is almost constant at the volume fraction of martensite higher than 33%.