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.