SCC behavior of solid-HIPed and irradiated type 316LN-IG stainless steel in oxygenated or hydrogenated water at 423-603 K

423-603Kの酸化性又は還元性環境中でのHIP接合した316LN-IG鋼のSSC挙動

三輪 幸夫; 塚田 隆 ; 實川 資朗

Miwa, Yukio; Tsukada, Takashi; Jitsukawa, Shiro

照射及び非照射316LN-IGステンレス鋼の熱間等方圧接合材の応力腐食割れ感受性に及ぼす水化学の影響を調べた。中性子照射は約200Cで約1dpaまで行った。応力腐食割れ感受性を調べるために、溶存酸素を10ppm又は溶存水素を1ppm含む150330Cの高温水中で、低ひずみ速度試験を行った。非照射材では、溶存酸素又は溶存水素を含むいずれの高温水中でも、粒界型応力腐食割れが330Cで発生した。照射材では、水化学の影響が240Cと300Cで異なった。溶存水素を含む高温水中では、300Cでは照射誘起応力腐食割れが抑制された。

Effects of water chemistry on the stress corrosion cracking (SCC) susceptibility of a solid hot-isostatic pressed (solid-HIPed) type 316LN-IG stainless steel was studied in unirradiated or irradiated condition. Neutron irradiation was conducted at nominal temperature of 473 K to dose level of 1 dpa. Slow strain rate testing (SSRT) was performed at a temperature range from 423 to 603 K in oxygenated (DO = 10 ppm) and hydrogenated (DH=1ppm) water. In unirradiated condition, intergranular (IG) type SCC occurred at 603 K in the oxygenated and the hydrogenated water. In irradiated condition, effects of water chemistry on IASCC susceptibility were different at 513 and 573 K. In the hydrogenated water, IASCC was suppressed at 573 K.