Formation Mechanism And Process Improvement Of Black Spots On High-quality Anodized Strip Surface Of 5252 Alloy

The formation mechanism of black spot on high-quality anodized aluminum strip surface of 5252 alloy and the improvement of the process quality of the cold rolling and cleaning process were studied in this paper.The mechanism of black spots was analyzed by macro and micro morphology observation and SEM analysis,and the influencing factors of cold rolling process and cleaning process were analyzed.The effects of roll roughness,process parameters and outlet side purging on aluminum surface oil stain and aluminum powder in cold rolling process were discussed.The influence of high pressure roller brush,nozzle angle,plate filter and squeeze roller set on black spots in cleaning process were discussed.The research found that by properly raising the rolling oil temperature,adopting the continuous rolling process and the outlet side purging optimization,the residual oil on the surface of the rolled coil can be effectively controlled and improved,thereby reducing the aluminum powder;properly improving the roll roughness and optimizing the pass times.The amount of pressing can effectively reduce the production of aluminum powder;the brushing area adjustment by high-pressure roller brush can effectively improve the surface cleanliness;the optimization of the filter aid can effectively improve the effect of the plate filter system and improve the cleanliness of the filtered water;The optimization of the roller unit effectively reduces the accumulation of aluminum powder on the roller surface.Through the cold rolling and cleaning processes,the number of black spots is reduced from 9000 to less than 400.The black spots are effectively controlled and the surface quality stability of the products is improved.