Technology And Mechanism Of Chemical Milling For DD6 Casting

Chemical milling process is a technology that uses chemical solutions dissolve the surface of workpiece and the theory of chemical and electrochemical corrosion. Chemical milling protective coating also called stripping coating, is a temporary protective coating during chemical milling process, after which must be wiped off. Despite a temporary protection during the chemical milling process, the coating plays a very important role.This paper aims to study a environmentally chemical milling protective coating with a good use of performance and good resistance to corrosion, which does not contain toxic solvent and is easy to dives after solidify. The environmentally chemical milling protective coating is formulated with acrylate modified organosiliane as the main film-forming agent, talcum powder and white carbon black as fillers, antioxygen 1010 and methylsilicone oil as additives, methyl carbonate and absolute ethyl alcohol as non-toxic solvent mixture. The coating shows good acid resistance, on the whole meets the requirements of chemical milling. To study the optimum technology of DD6 casting, using the Orthogonal experimental method to determine the formula of acid-based hemical milling solution with moderate milling speed and higher surface finish,The experimental results show that when the temperature is 30℃,the optimized formula is as follows:chromic anhydride 20 g/L,nitric acid 120 ml/L, hydrochloric acid 150 ml/L and hydrofluoric acid 185 ml/L, Under this formula the sample surface shows good uniformity and that the chemical milling process is stable and controllable.