The corrosion of a low alloy steel in a steam turbine environment: The effect of oxygen concentration and potential scan rate on input parameters used to computer match the experimental polarization curves

The corrosion behaviour of A-470 low alloy steel in a simulated low pressure steam turbine environment at ambient temperature has been examined as a function of dissolved oxygen (DO 2) concentration. A computerized routine was used to synthesize, match and deconvolute experimental potentiodynamic polarization curves. The empirical relationships between the input parameters required to match the experimental polarization curves at different potential scan rate (v) and DO 2 levels has been established. The effect of increasing DO 2 level and v parallel one another. The DO 2 concentration resulting in spontaneous passivation was between 0.05 and 0.10 ppm whilst concentrations between 2.50 and 3.00 ppm led to instantaneous pitting.