A Study of the Mechanisms and Kinetics of the Localized Corrosion Aggravation of Ductile Iron in a Harsh Water Quality Environment

Ductile iron is a high-strength cast material. The spherical graphite obtained by inoculation treatment effectively improves the mechanical properties of iron, resulting in higher strength than carbon steel. However, severe corrosion may occur under specific circumstances, especially thermal water pipelines. In this paper, mechanisms at main defective points ductile were investigated using microscopic morphological characterization after accelerated tests combined with numerical simulations. influence law each environmental factor on kinetics complex quality environment was studied dynamic potential polarization tests. results showed that causative factors leading to increased presence tail-like gaps its surface, and crescent-shaped shrinkage loosening organization around spheres. After applied eliminate obvious defects, number pits reduced 41.6%, depth slowed down 40% five days. By comparison, ten days, 51%, 50%. test show dissolved oxygen concentration has greatest simulated environment; meanwhile, hardness can slow iron. relative as follows: > temperature immersion time pH Cl−.