Fretting Corrosion Behavior of 316L Stainless Steel Heat Exchanger Tube in NaCl Solution

The heat exchanger tube of pressurized water reactor (PWR) steam generator is the key component between primary circuit and secondary circuit. Due to the flow induced vibration (FIV) of the heat exchanger tube bundle, fretting corrosion will occur between the heat exchanger tubes and the supports. Under the synergism between wear and corrosion, it would be accelerated that the failure of heat exchanger tubes. Therefore, in this study, the self-designed fretting corrosion experimental equipment was used to conduct fretting corrosion experimental studies on 316L stainless steel, commonly used as steam generators tube in nuclear power plants, in sodium chloride (NaCl) solutions with different concentrations (mass fraction of 1%, 3.5% and 5%), respectively. The corrosion tendency and corrosion rate of the tube were analyzed by electrochemical technology. The fretting corrosion behaviors of 316L stainless steel in NaCl solution and the effects of ion concentration on fretting corrosion behaviors were studied, and the synergism between corrosion and wear was quantitatively analyzed. The surface of the wear scars were analyzed by Scanning Electron Microscope (SEM) and white light confocal three-dimensional profilometer. Combined with these test results, the damage mechanism of fretting corrosion was analyzed. The research results reflect the synergistic mechanism between wear and corrosion, but considering the difference between the experimental setting and the operating conditions of PWR steam generator, the experimental results can’t be directly used to predict the wear of heat exchanger tubes.