On-Line Measurement and Characterization of Electrochemical Corrosion of 304L Stainless Steel Pipe Wall in High-Speed Cl-Containing Solution

Abstract

Fluid-induced metal corrosion failure is one of the main causes of pipe wall damage. In this paper, aimed at the corrosion failure of stainless-steel pipe wall in high-speed flowing liquid, a self-made micro three-electrode electrochemical test system was used to test the electrochemical characteristics of the pipe under different flow rates and different Cl− concentrations. In the experiment, the changes of open circuit potential, polarization curve and impedance spectrum of 304L stainless steel surface were obtained. At the same time, the corrosion rate of the material under different conditions was obtained by fitting. The results show that the corrosion rate varied non-linearly with increasing flow velocities. In addition, with the increase of Cl− concentration, the corrosion rate increased at a slower rate. The material surface under high concentration and high flow rate conditions was subject to physical cutting and electrochemical reactions, showing an activated and easy pitting corrosion state. The results of this study can provide data for failure analysis and life extension of pipelines and equipment in service.