Environmental compatibility evaluation of extra high purity stainless steel (EHP alloy)
江藤 淳二 Junji ETOH 芦田 高規 Takaki ASHIDA 落合 孝正 Takamasa OCHIAI 木内 清 Kiyoshi KIUCHI 滝沢 真之 Masayuki TAKIZAWA 中山 準平 Junpei NAKAYAMA
Austenitic stainless steelCorrosionEnvironmental assisted crackingExtra high purity
An elemental factor on the crack propagation mechanism of SCC observed in LWRs component materials made of non-sensitization stainless steels is examined with respect to the local steam corrosion in cracks by atomic oxygen formed at the wall surface under the irradiation of γray. The excellent oxidation resistance of type 25Cr-35Ni EHP steel with forming the protective double layer oxides is observed up to 600℃. On the other hand, the oxidation of type 316L steel with non-protective single oxide is accelerated at the high temperature region accompanied with the internal oxidation due to dissolved oxygen. The oxidation of type 316L steel in crevices is markedly accelerated with increasing the oxygen atom density excited byγray .