Corrosion Behavior of 12Cr-F/M Steel in Supercritical Water

The mechanical properties of 12Cr-F/M steel at 550/650 ℃ and SCC performance at 550 ℃ in supercritical water (SCW) were studied using slow strain rate testing (SSRT). And the general corrosion behavior of 12Cr-F/M steel in SCW at 550 ℃ was studied. The results of SSRT showed that 12Cr-F/M steel had good mechanical properties in SCW at 550 ℃, and its mechanical strength decreased significantly when the temperature was 650 ℃, but its elongation was basically unchanged. The result of ex-situ scanning electron microscopy (SEM) showed that 12Cr-F/M steel had IGSCC susceptibility in SCW at 550 ℃. The result of general corrosion experiment in supercritical water showed that 12Cr-F/M steel had low resistance to general corrosion, and the weight gain was subject to Parabolic growth law. At 600 h, the rupture of oxide film occurred, and the oxide film suffered exfoliation at 1 000 h. It is assumed that this exfoliation resulted from the inconsistency of thermal expansion between the matrix and the oxide during the cooling period.