抄録
During potentiostatic corrosion fatigue test, fluctuation of polarization current which is synchronized with the cyclic tension-compression loading was observed. This current fluctuation means that the corrosion rate was accelerated by the cyclic loading. Using Fourier transformation, we separated the current component of this accelerating which is synchronized with the cyclic loading from the polarization current. We named this component of the current "Stress Synchronized Polarization Current (SSPC)" and compared it with the fatigue life.
Corrosion fatigue test for high tension steel HT60 was carried out in artificial seawater solution and in borate solution under the condition of bend type specimen potentiostatically. In the artificial seawater, except the potential range where prominent general corrosion or hydrogen embrittlement occurred, there was a good correlation between SSPC and the fatigue life. Under the potential where SSPC was low, corrosion fatigue damage was also small and then fatigue life was longer. This correlation is further clear in the borate solution in which the passive film formed. The result suggests that the SSPC, which can be measured at the early stage of fatigue test, is useful to estimate the corrosion fatigue damage quantitatively.
