Quantitative characterization of Q235B steel electrochemical corrosion by acoustic emission

The mechanism of dissolving acoustic source of Q235B corrosion anode metal is the basis of acoustic emission (AE) source identification and corrosion site evaluation and analysis. In this paper, the local mechanical energy release and the characteristics of radiated elastic wave pulse in the process of metal dissolution are analyzed by using the principles of corrosion dynamics, damage thermodynamic energy conversion, local mechanical energy release and radiation elastic wave pulse characteristics of metal dissolving process, and the theoretical analysis is verified by atomic first numerical method. Combined with AE and electrochemical testing technology, the mechanism of Q235B steel corrosion acoustic source is studied experimentally. The characteristics of the metal dissolved acoustic source are obtained, and the energy conversion value of anode metal in the process of dissolution is extracted. The quantitative characterization formula of the corrosion behavior of the AE is established, which provides a basis for the assessment of the severity of the corrosion state of Q235B steel. •Under the action of electrochemical driving force, the breakage of crystal bonds triggered by the metal atoms leaving the lattice and the jumping mechanical motion of metal atoms in the phase boundary region are accompanied by the radiation of elastic wave pulses, forming the AE source.•The numerical results of the energy released by atoms during corrosion are obtained using atomic first nature numerical calculations. Dissolution of anode metal can be used as the basis for AE detection of Q235B steel corrosion.•A quantitative characterization formula of the corrosion behavior of the AE is established, which provides a basis for the assessment of the severity of the corrosion state of Q235B steel.