Development and Application of Repairing and Protection Technologies for Desulfurization Pump

摘要

Gypsum and slurry with high content of Cl~- lead to the damage of desulfurization pump caused by erosion and corrosion. Gas tungsten arc welding (GTAW) and shield metal arc welding (SMAW) were employed to develop weld repairing technology. High-velocity oxygen fuel (HVOF) spraying was employed to prepare NiCr cermet coating and WC cermet coating against erosion and corrosion. Microstructures and mechanical properties of the weld and the protective coatings were tested. The mechanical properties of the weld joints with duplex microstructure were in accordance with related standards. The technology of HVOF sprayed NiCr cermet coating was selected to prolong the service lifetime and was applied on the pump casing and impeller repaired by using the weld repairing procedures developed in this study. The integrity of the pump parts after 30 months in-field service confirmed the reliability of the repairing technology and the protection technology.