ステンレス鋼の高温食塩水による応力腐食に及ぼす温度の影響

抄録

A study on the stress-corrosion cracking of austenitic stainless steels in high temperature sodium chloride solutions was carried out to estimate the effects of temperature, chloride concentration and dissolved oxygen contents on the susceptibility. Four types of stainless steels of AISI Type 304, 304L, 316 and 347 were corroded in high temperature sodium chloride solutions (temp.: 100°-350°C, Cl^-: 10-500ppm) for 300 hours under a bending stress of 20kg/mm². In deoxygenated solutions, no corrosion cracking was detected in any case. In oxygenated solution, pronounced cracking on 304, 304L and 347 steels was detected at the temperatures between 150°C and 300°C, but no cracking was detected at 350°C. The solution-treated 316 steel indicated no cracking in any case, while, on the contrary, the sensitized one indicated the cracking as well as the other three types of steels.