Development of a Novel Process of Corrosion Rate Estimation of Steel under Stray Current Interference: Q235A Pipe Steel as an Example

With the progress of urbanization, stray current corrosion has attracted numerous attention due to its safety threaten to buried metallic pipelines around the urban rail transit system, especially to gas pipelines. A method to monitor the corrosion rate of the gas pipeline is urgently needed in view of the existing indirect method of the long-life reference electrode. In this work, a novel process model of corrosion rate estimation steel under stray current interference was proposed. The electrochemical noise (EN) signal was studied in the frequency domain through combined analysis in terms of fast Fourier transform (FFT) and discrete wavelet transform (DWT). According to the energy value of each crystal, the active energy was proposed as a parameter for the estimation of the corrosion rate under the excitation of stray current. The results showed that there is a negative correlation relationship between corrosion rate rcorr and active energy Ea. Thus, the active crystal energy of EN signal may be applied as the possible monitoring method of corrosion hazard during the stray current corrosion process.