Comparison of critical flow velocity for erosion-corrosion of six stainless steels in 3.5 wt% NaCl solution containing 2 wt% silica sand particles.

Abstract Critical flow velocity (CFV) is one of the valid parameters to evaluate the erosion-corrosion performance of passive materials. The comparison of CFV for common passive materials is significant for the engineering applications. This study focuses on the comparison of CFV for different types of stainless steel (SS), including the pearlitic 2Cr13 SS, austenitic 304 SS, 316 SS, 254 SMO SS, and two duplex stainless steels (DSS) (2205 DSS and 2507 DSS) in 3.5 wt% NaCl solution containing 2 wt% silica sand particles using the impingement jet apparatus. Different methods (potentiostatic polarization tests, mass loss measurements and surface roughness measurements) were used to determine the CFV and the values of CFV derived from different methods showed a good consistency. The 254 SMO SS exhibited the highest CFV, followed by 2507 DSS, 2205 DSS and 316 SS, and 304 SS and 2Cr13 SS. Compared with the mass loss method which is normally time-consuming, comprehensive evaluation based on the critical flow velocity and current density at flow velocity higher than the critical value by using potentiostatic polarization tests is more effective and efficient for the material selection for erosion-corrosion. Highlights • The critical flow velocity (CFV) of six stainless steels is compared. • The CFV determined by different testing methods is consistent. • CFV is a valid parameter to evaluate erosion-corrosion behavior of passive materials. [ABSTRACT FROM AUTHOR]