汽车车身用钢板可分成内用板和外用板，所要求的性能是不同的，车门等袋状结构部的内部难以涂料，所以要求钢板不涂涂料具有非常好的耐蚀性。而车身外部用钢板因为眼睛直观得到，要求涂上美丽的涂料。目前汽车用钢板原板是镀Zn—Ni钢板，大多数只在内表面镀一层铬酸盐和一层透 Automotive body steel plate can be divided into internal and external panels, the required performance is different, such as the interior of the door pocket structure is difficult to paint, so the requirements of the steel plate is not coated with a very good corrosion resistance. The outer body with a steel plate because the eyes get intuitive, require the application of beautiful paint. At present, automotive steel plate is Zn-Ni steel plate, most of the inner surface only coated with a layer of chromate and a layer of through