Erosion-corrosion of stainless steel at different locations of a 90° elbow

• Erosion-corrosion rate of stainless steel is higher at the outer wall of elbow outlet.
• The passive film at the outer wall of elbow outlet is less stable.
• There is galvanic effect at the different locations of stainless steel elbow.
• The outer wall of elbow outlet is anode with more negative potential.
• The outer wall of elbow inlet and the inner wall is cathode.

Erosion-corrosion (E-C) behaviour of stainless steel at different locations of a 90° elbow was studied by array electrode technique. It is demonstrated that more negative corrosion potential and pitting potential, higher passive current density, and higher E-C rate appear at the outer wall of elbow outlet. The electrodes at the outer wall of elbow inlet and at the inner wall act as cathodes while the electrodes at the outer wall of elbow outlet as anodes after coupling. The passivation behaviour and galvanic effect of stainless steel elbow are associated with the hydrodynamics and sand particles distribution at the elbow.