The mechanism of erosion and corrosion of steels in lead–bismuth eutectic (45Pb–55Bi) flow was investigated. Nine
steels were simultaneously exposed to the Pb–Bi flow at the temperature of 550C, the loop temperature difference of
150C, and the flow velocity of 2 m/s for 1000 h. The liquid metal corrosion, or Pb–Bi penetration into steels occurred
in all the steels, and severe erosion took place in some of the steels under low oxygen concentration of 2·10
^-9 wt% in Pb–Bi. The corrosion layer penetrated by Pb–Bi was deeper in the steels containing a lower content of Cr. It was con-firmed that the erosion was caused by hydrodynamic carrying away of weakened surface materials due to Pb–Bi pen-etration. The large-scale erosion could be caused by the detachment of lumps of corroded materials that had defects
formed by dissolution of alloying elements.