Electrochemical behavior and corrosion rate prediction study of alloy 690

Abstract

Alloy 690 is a material commonly used in heat transfer tubes of steam generators (SGTs). The electrochemical corrosion behavior in different volumes (V) of NaCl–Na2S2O3 solution for different surface roughness (Ra) of alloy 690 was studied, and a BPNN model for predicting electrochemical corrosion parameters of alloy 690 was established (CP and CCD). The results show that Ra on the surface of alloy 690 destroys the passivation film and changes the oxygen vacancies in the passivation film, so that Cl− is more easily attached to the passivation film. Finally, accelerated electrochemical reactions on the surface of SGTs. When the solution is Na2S2O3, with the increase of Ra on the metal surface (0.0977≤ Ra ≤ 1.1661), the corrosion potential gradually decreases. BPNN can accurately predict the electrochemical corrosion rate of alloy 690 under different conditions, and the relative error is less than 10%. In this paper, an artificial intelligence model is established for the first time to predict the relationship between Ra and electrochemical corrosion, and the conclusion can be used to schedule the maintenance process of the SG, thereby reducing the risk of structural failure and maintenance costs.