Abstract: In view of the cleaning of the surface fouling of the valve external cooling radiator in the converter station, the existing industrial cleaning scheme has the following technical difficulties: 1)The main component of the valve external cooling fin is aluminum.The aluminum substrate is chemically active and sensitive to acidic or alkaline chemicals, which is easy to cause corrosion.2)The structure of the cold radiator outside the valve is complex, and the cleaning tooling is prone to leakage of cleaning fluid.With the analysis of the causes of fouling on the surface of the cold radiator outside the valve, based on the analysis results of the fouling sample composition, an improved circulating spray chemical descaling and cleaning method was proposed.A special cleaning agent and aluminum corrosion inhibitor for the radiator were developed, while effectively removing the fouling on the surface of the radiator, the fins were not corroded and the leakage was prevented.