Effect of surface roughness on the fretting corrosion behavior of Inconel 690 alloy tube

Abstract Surface roughness which is an important index to evaluate a material’s surface properties, can strongly influence the service performance of steam generator tubes in nuclear power plants. This study used experimental tests and finite element analysis to investigate the fretting corrosion mechanisms of Inconel 690 alloy tubes of three roughness surfaces (Sa “Surface Roughness Average” ≈ 0.09, 0.25, and 0.50 μm) under 25 ℃ and 100 ℃ artificial sea water (3.5% NaCl solution) conditions. Results showed that surface roughness affected the fretting damage and electrochemical corrosion behavior of the alloy tubes significantly. This is mainly due to surface roughness also belongs to a kind of micro-defects, which would influence the fretting contact state and corrosive medium effect, and temperature influenced oxidation. All these conditions led to different fretting corrosion damage.