Flow Accelerated Corrosion of Stainless Steel 316L by a Rotating Disk in Lead-Bismuth Eutectic Melt

Abstract

Stainless steel 316L specimens were snug fitted into a rotating disk submerged in molten LBE and subjected to spatially varying local flow velocity along the radial position. The specimens experienced LBE flow velocity from 0.50 m/s to 3.14 m/s depending on their radial location. The test was conducted at 600 degrees C with an oxygen concentration of 2.87 x 10(-8) wt% for 150 h. Resulting microstructural characteristics of the corroded zone were found to be sensitively affected by local flow velocity and were categorized into four regimes. For linear disk velocity > 2.0 m/s, the affected zone thickness became increasingly less sensitive to flow velocity as the overall reaction became reaction rate controlled. At the velocity of similar to 3.0 m/s, erosion-corrosion started to take place. The flow effect on the affected zone thickness (l) agreed with the model based on the disk velocity (v) effect on the mass transfer of a rotating disk as 1/l similar to v(-0.792).