Preliminary Study on Mn-Related Corrosion of Condenser Stainless Steel Tubes

A lot of pitting of condenser stainless steel(SS) tubes induced by MnO2 took place in USA and some other countries. With the increase of SS condenser quantities and service time in our country, the similar problem may also take place. But no research reports in this field were published. The formation of MnO2 on SS tubes has two main ways, microorganism oxidation and chemical oxidation. The open circuit potential(OCP) value will rise dramatically to around 400 mV(vs.SCE) no matter how MnO2 forms on stainless steel surface. The noble shift can elevate OCP above the critical pitting potential and induce pitting of 304, 316L SS tubes.