Processing technology for improving corrosion resistance of iron casting

The invention discloses a processing technology for improving the corrosion resistance of an iron casting. The method has the beneficial effects that the iron casting is processed and modified by adopting a processing mode of combining two times of salt bath treatment, two times of graded polishing treatment and single time of oxidation treatment, on one hand, a compact oxidation layer can be formed on the surface of the iron casting, and the oxidation layer is prepared by firstly performing salt bath treatment, carburizing and nitriding and then performing oxidation; therefore, the corrosion resistance and the wear resistance of the iron casting are greatly improved, the defect that the iron casting is easy to corrode and wear in the using process is effectively avoided, the service life of the iron casting is prolonged, and the service life of the iron casting is prolonged. And on the other hand, the uniformity of an oxide layer on the surface of the finally prepared iron casting can be ensured through a ma