To obtain the corrosion behavior of a widely-used boiler steel (15CrMo) exposing to saline gas and saline water with sodium sulfate (Na2SO4), the experiments were designed and implemented. The samples were analyzed by scanning electron microscopy/energy disperse spectrum (SEM/EDS) and X-ray diffraction (XRD). The results show the different corrosion behavior between liquid phase and gas phase. The particles among corrosion products in gas phase are larger than that in liquid phase corrosion. The crystal structures of Fe3O4 could fully form in gas phase. The corrosion products in liquid phase are complicated, including Fe, Fe2O3, Fe3O4. The corrosion behavior of 15CrMo in saline circumstances could deeply influence the efficiency and safety of the boilers.
Keywords Steam-injection boiler, Corrosion, Saline circumstances, 15CrMo steel