Corrosion Behavior of Steels in Lead-Bismuth Eutectic - In Stagnant LBE Test at Low Oxygen Partial Pressure -

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古川 智弘  ; 古川 智弘*; 吉田 英一; 青砥 紀身 

Furukawa, Tomohiro; Furukawa, Tomohiro*; Yoshida, Eiichi; Aoto, Kazumi

極低酸素ポテンシャル下停留鉛ビスマス中にて2.25Cr-1Mo,Mod.9Cr-1Moおよび12Cr鋼の550-2,000h浸漬試験を実施した。3鋼種ともに、本試験条件下では良好な耐食性を示した。腐食深さは数ミクロンであり、構成元素であるCrのLBE中への溶出が観察された。試験片表面には、部分的にクロム酸化物の形成しており、同部には腐食が観察されなかった。これらの腐食挙動は10-710-8wt%-O2下で試験した試験片の挙動と同様であった。

Corrosion test of three chromium-molybdenum steels -2.25Cr-1Mo, Mod.9Cr-1Mo and 12Cr-steel (ASME P122) - has been performed in stagnant lead - bismuth eutectic (LBE) at low oxygen partial pressure at 550C up to 2,000 hours. After the test, the specimens were metallurgically examined using a scanning electron microscopy.All steels had good resistance to LBE under this test condition, and the difference of the effect of chromium concentration in the steels on corrosion behavior was not observed. Corrosion depth of the steels was a few microns, and chromium solution into LBE was observed on the surface. Very thin chromium oxide layer was partly observed on the surfaces of all steels. At the area, no corrosion was occurred. The behavior was the same as the results of martensitic steels tested in stagnant LBE containing 10-7 wt% to 10-8 wt% of oxygen.