Corrosion behavior of D32 steel for offshore platforms at the splash zone

The corrosion behavior of D32 steel for offshore platforms was studied at the splash zone with polarization curves and electric impedance spectroscopy (EIS). Scanning electron microscope (SEM) and energy dispersive spectrometer (EDS) were employed to analyze the corrosion rusts. Because of different microstructures, components and cover degrees of the corrosion rusts, the samples at the immersion zone corroded a little more seriously than those at the seawater, whereas the samples at the splash zone corroded much more seriously than those at the immersion zone. It was due to the rust layer and calcium magnesium layer formed on the surface of the steel that the Warburg impedance appeared in the Nyquist figure at the immersion zone and splash zone of Qingdao and Chengdao seawater.