The Influence of Critical Flow Velocity on Corrosion of Stainless Steel

Abstract

In order to find out the effect of fluid flow velocity on electrochemical reaction, the electrochemical parameters of super 13Cr stainless steel in 3.5% NaCl aqueous solution were measured by a jet flow system at different flow velocities. The electrochemical characters such as open-circuit potential and polarization curve were monitored online using a three-electrode electrochemical system. The results show that the increase in wall shear stress caused by the high flow velocity leads to the rupture of passive films and the exposure of fresh metal in the corrosive media, which cause the increase in corrosion rate. Meanwhile, the corrosion rate shows a significant growth when the flow velocity is less than 0–10.0 m/s. But it gradually decreases after reaching a maximum value.