Velocity effect on general corrosion and pitting of Ni-resist D-2 in 3.5% NaCl

General corrosion and pitting rates of an austenitic Ni-Resist cast iron Type D-2 (ASTM A439-80) was evaluated in aerated 3.5% NaCl at different fluid velocities using potentiodynamic test and rotating electrode. It is found that, within the range of Reynolds numbers investigated, corrosion and pitting rates are directly related to the velocity, the former with a linear relationship and the latter with an exponential relationship of the type mpy pitt =2.45 (V) 0.25 . In both cases, corrosion rates were lower than those quoted for Ni-Resist Type 2. The results were explained an a basis of the difference in graphite morphology