Corrosion fatigue behavior and life prediction of butt-welded joint considering loading frequency

Corrosion fatigue (CF) experiments of G20Mn5QT cast steel and Q355D steel butt-welded joint are conducted with loading frequencies of 1 Hz and 10 Hz. The decrease of loading frequency resulting in a reduction in the CF life of specimens. The average percentage of CF life reduction are 6.4% (S = 300 MPa), 53.5% (S = 260 MPa), 17.5% (S = 220 MPa), 34.3% (S = 190 MPa), 38.6% (S = 160 MPa) and 80.5% (S = 130 MPa), respectively. The CF failure mechanism remains unchanged regardless of the loading frequency. Based on continuum damage mechanics (CDM), a novel CF life prediction model is proposed, in which the effect of loading frequencies is introduced by the evolution of corrosion pits. The prediction model considers the coupling effect of fatigue and corrosion, and it achieves the prediction of CF life of the butt-welded joints using experiment data at higher loading frequency. The accuracy and universality of the prediction model are verified by predicting the CF life of other specimens.