Aiming at improving the anti-melting-loss property of the 8407 die steel, room-temperature hard anodization treatment was carried out for aluminized 8407 steel in order to form an oxide film on the surface. The influences of current density and oxidation time on the thickness and hardness of the film were discussed, and the optimum oxidation condition was obtained. The influence mechanism of oxidation condition on thickness and hardness of the film was analyzed. Furthermore, the sectional microstructure and surface morphology of the film were observed by means of OM and SEM, and the phases in the layer were determined by using XRD. The results show that a uniform, compact and tightly united Fe3O4·Al2O3 film has been obtained on the 8407 steel surface after aluminization and subsequent room-temperature hard anodization treatment. Its thickness is 24~67 μm and hardness is 335~382 HV. The optimum oxidation condition is as follows: current density being around 2.5 A/dm2, oxidation time being around 60 minutes and oxidation temperature being around 25 °C.
