Stability of oxide layer formed on high-chromium steel in LBE under oxygen content and temperature fluctuation

鉛ビスマス中で高クロム鋼表面に形成する酸化物層の酸素濃度及び温度変動条件下の安定性

Weisenburger, A.*; 青砥 紀身 ; Mller, G.*; Heinzel, A.*; 古川 智弘  

Weisenburger, A.*; Aoto, Kazumi; Mller, G.*; Heinzel, A.*; Furukawa, Tomohiro

代表的な高Cr鋼であるP122とODSについてLBE中の保護的酸化皮膜の安定性を評価するために酸素濃度変動及び温度変動条件の浸漬試験を実施した。P122については溶接継手についても試験した。P122と継手に関する550C、800時間毎に酸素濃度が10 wt%と10 wt%に交互に変化する試験結果では酸素濃度が良好に110 wt%に維持された場合と同様スピネルの保護層は維持されていた。ODSについては10 wt%と10 wt%条件で800時間毎に550Cと650Cになる試験を行なった。前者では保護層が維持できたが後者では650C、10 wt%一定条件の場合と同様にLBE腐食が進行した。

The behaviour of protective oxide layers on P122 and its welds and of ODS steel in LBE is examined under conditions of changing temperatures and oxygen concentrations. P122 teel (Cr) and its welded joints are exposed to LBE at 550 C for 4.000 h with oxygen concentrations of 10 and 10wt% which change every 800 h. It is found that like in case f constant oxygen concentration of 10 wt% a protective spinel layer was maintained on P122 and also on its welded joint. Two experiments are conducted on ODS steel, both with temperatures changing from 550 to 650 C and back every 800 h, one experiment with 10 the other with 10 wt% oxygen in LBE. Like in the former test with constant emperature at 550 C no dissolution attack could be observed in experiments with temperature fluctuation. Contrary to this results is the observed dissolution attack on ODS with a onstant temperature of 650 C at 10 wt% oxygen in which formation of a protective layer was not allowed before reaching 650 C LBE temperature.