Improving the Corrosion Behavior of Ductile Cast Iron in Sulphuric Acid by Heat Treatment

In this investigation, the effect of heat treatment on the corrosion behavior of ductile cast iron (DCI) in H2SO4 environment has been conducted. Moreover, the effect of heat treatment on the mechanical properties has also been investigated. The change in microstructure of DCI is obtained by austenetising at 900°C for two hours followed by oil quenching and then heated to 700oC for different tempering times. The corrosion measurements were tested using anodic potentiodynamic polarization and cyclic polarization techniques. Here we show that the tempered specimens at different tempering times show better corrosion resistance in H2SO4 solution than that without heat treatment. Moreover, the polarization measurements showed that the Ecorr and ia of the different specimens increase with increasing H2SO4 concentration while both Epass and ipass were decreased.