Precise Calculation Of Body E-coating Films And Research On Influence Of E-coating Holes

Being the foundation of body anti-corrosion, the e-coat film has high corrosion resistance. While surfaces in cavities are more difficult to be coated than outside surfaces because of the more complex structures, which could lead to corrosion problems.The “trial and error” method is often taken to solve engineering corrosion problems, This method is expensive and hard to solve the problems completely. The numerical analysis technology for e-coating process has been developed rapidly in recent years, making it possible to predict the film thicknesses in cavity. But present works are limited to simple simulation and verification, and valuable conclusions have not been proposed to be applied in structure design.According to solve the problems mentioned above, the ‘overall and local’ method is introduced and the precise calculation for the thicknesses of body e-coating film is accomplished. And a strategy for conventional design of body e-coating holes is firstly proposed, which is called regional analysis method.Firstly the electric field information in e-coating process is obtained and the electrochemical simulation environment is established. The basic deposition parameters of paint are also obtained by experiments and simulations.Then a e-coating simulation model of a body is built based on previous work, and the simulation results and measured results match well. The growth of film in cavity is deduced based on the numerical analysis.Then a fully coupled electrochemical e-coating simulation model of the simplified regional structure of frame was built based on this work. The sizes and shapes of e-coating holes were taken as variables to do the research by electrochemical analysis method. The results show that the sizes have great effects on film thickness while the shapes almost have no influence on film thickness. Numerical disciplines of film decay were found, and the safety factor of film decay was then deduced. The safety factor of pitch of holes was deduced by analyzing the situation of two holes.The quantized results were applied in structure improvement of a frame and the corrosion was successfully eliminated, proving that the method is of great practicality.