Aluminum plate products are widely used in industries such as automobiles and construction. Improving the quality of aluminum products is the foundation of the survival of enterprises. Aluminum materials are extremely unstable in the air and easily generate oxide films that are difficult to identify with the naked eye. Due to the different processing methods of aluminum parts, such as casting, or directly cut from rolled sheets, or mechanically finely processed, or formed by different processes and then heat treated or welded, the surface of the workpiece will appear Different states, different degrees of dirt or traces, for this reason, the pre-treatment process must be selected according to the actual situation of the workpiece surface in the pre-treatment process.
It should be noted in the pretreatment process that not all surfaces of the cast molded parts have been mechanically processed. The unprocessed surface has an excessively thick oxide layer formed during the casting process, and some have a sand layer. In this case, the machine should be used first. The processing or sandblasting method first removes the original oxide film of this part, or processes it after alkaline washing. Only in this way can the original oxide layer of the unprocessed part be removed, and the change of the tolerance size of the machined part can be avoided.
Problems that need to be paid attention to in the pre-treatment process of finely processed parts: Although the natural oxide film on the surface of finely processed parts is only initially formed, which is easier to remove, it is greasy and heavy, especially in and around the holes. This kind of work must first be treated with organic solvents. For cleaning, if it is directly washed with alkali, it is not only greasy and difficult to remove, and the finely processed surface cannot withstand long-term strong alkali corrosion. As a result, it will also affect the roughness and tolerance of the workpiece surface, and it may eventually become a waste product.