Polishing Process and Its Affecting Factors of Chemical Milling for 2197 Al-Li Alloy

The solution formula of polishing process for 2197 Al-Li aluminum alloy was determined by orthogonal experiments, and the major influencing factors of material status, polishing temperature and polishing time were investigated. The results showed that the concentration of HNO3 and temperature were the main factors influencing the polishing effect. The second was CrO3, HF had the minimum influence. Different states of materials had great influence on the polishing, T8 state aging of aluminum lithium alloy had the minimum roughness after polishing, T6 state short aging aluminum lithium alloy had the maximum roughness after polishing. Under the conditions of HHO3 250 g/L, CrO3 10 g/L, HF 2 g/L, polishing temperature 25 ℃ and polishing time 2~3 min, good performance of surface polishing could be obtained.