Repair method for steel storage tank corrosion pit

The invention relates to a repair method for a steel storage tank corrosion pit and belongs to the technical field of welding. A pit after repair comprises three parts, including aluminum for filling up the pit, an aluminum-sprayed erosion resistant coating on the inner surface and a carbon fiber sheet back-up coat on the outer surface. In the repair method, the aluminum for filling up the pit plays the roles of smoothing tank wall and facilitating construction of the erosion resistant coating in later period and delaying of tank wall corrosion because the erosion resistant coating is used as a positive pole after corrosion perforation; the aluminum-sprayed erosion resistant coating on the inner surface can isolate direct contact between stored matter and steel of the tank wall and play the roles of delaying or even stopping further erosion and protecting the tank wall; the carbon fiber sheet back-up coat on the outer surface plays the roles of solidifying the tank body and shearing internal pressure so as to prevent discarding of the storage tank caused by the fact that the tank wall is thinned and cannot bear internal pressure. The combined use of the three parts can lastingly and effectively protect and solidify the storage tank.