A stochastic study of the effect of the phase ratio on the corrosion resistance of duplex stainless steel

The effect of the phase ratio of austenite and ferrite on the pitting potential (Epit) and passive current density of ASTM A890 grade 3A duplex stainless steel (DSS) was investigated using a stochastic method. The cumulative probability of the Epit value of DSS at different potential sweep velocities was linear, indicating that the pitting potential obeyed a normal distribution. In addition, the relationship between the pitting potential and the potential sweep velocity at various phase ratios was fitted by Epit proportional to log(v). The increase in ferrite promoted the sensitivity of the DSS to the potential sweep velocity. When the phase ratio of austenite and ferrite was 1:1, it showed better corrosion resistance. The phase ratio affected the passive current density more significantly than pitting potential.