Contribution of anodic dissolution to the corrosion fatigue crack propagation of X80 steel in 3.5 wt.% NaCl solution

The relation curves between the current density increment and the strain at crack tip of X80 steel in 3.5% NaCl under different strain rates were obtained. A formula that expresses the relationship between crack propagation rate caused by anodic dissolution, (da/dN)AD, and strain rate was established. The corresponding (da/dN)AD under different ΔK were calculated using the corrosion fatigue test results and the formula for calculating the strain rate at crack tip. A difference of three orders of magnitude between (da/dN)AD and the total da/dN was observed. Anodic dissolution was not the main cause of corrosion fatigue crack propagation of X80 steel in 3.5% NaCl.

► A formula was set up that expresses the relationship between (da/dN)AD and strain rate. ► The corresponding (da/dN)AD were calculated under different range of stress intensity factor. ► The (da/dN)AD is three orders of magnitude smaller than the total da/dN. ► Anodic dissolution is not the main crack propagation mechanism of X80 steel in 3.5% NaCl.