CORROSION BEHAVIOR OF STEELS IN LEAD-BISMUTH EUTECTIC - In Stagnant LBE Test at Low Oxygen Partial Pressure

摘要

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 550°C 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{sup}(-7) wt% to 10{sup}(-8) wt% of oxygen.