抄録
Effect of yield strength on stress corrosion cracking (SCC) of stainless steels in high temperature water environments was investigated experimentally and theoretically. In the experiment, warm forging in 200-290℃ range was used to raise the yield strength of mill annealed Type 304 steel to different levels but keep the same phase constitute. The SCC crack growth in oxygenated pure water at 288℃ was examined by using disk-shaped compact tension specimens with trapezoidal wave loading. The specimen with higher yield strength exhibited higher crack growth rate. Theoretical approach based on Shoji's model showed quantitatively that higher yield strength caused higher strain rate at SCC crack tip and subsequently higher crack growth rate. The theoretical results were in good agreement with the experimental results. The theoretical approach also showed that the yield strength effect was more significant in the situation where the materials had higher repassivation ability such as sensitized steels in oxygenated environments or had lower strain hardening ability.
