[en] Corrosion tests of martensitic and austenitic steels were performed in a forced liquid eutectic Pb-Bi circulation loop. Experiments were carried out at 470 deg C and 600 deg C. Two oxygen concentrations in Pb-Bi were studied: 10^-6 wt % and 10^-7-10^-8 wt %. The results showed that at 470 deg C, all the tested steels have a satisfying corrosion behaviour for both oxygen contents. An oxide layer is formed on martensitic steels (T91 and EM10); its thickness depends on the oxygen content. It is constituted of an outer layer of magnetite and an inner (Fe, Cr)₃O₄ spinel layer. Austenitic steel 316L is protected by a very thin oxide layer (< 1 μm). At 600 deg C, martensitic steels (T91 and EM10) undergo an important oxidation for both oxygen contents (after 1000h, the thickness of the oxide layer varies from 10-15 μm to 20-25 μm depending on the oxygen content). The oxide layer is constituted of (Fe, Cr)₃O₄ spinel and appears porous. Austenitic 316L undergoes severe dissolution at the lowest oxygen content in Pb-Bi and partial dissolution and oxidation at the highest oxygen concentration. Erosion phenomena were observed on all the steels. (authors)