Before the production of color coated plate, it should be ensured that there is no dust and other foreign matters in the curing furnace, so as to avoid defects caused by falling on the surface of the coated plate during production. When the film absorbs moisture, it is easy to appear swelling, chalking and other abnormal phenomena. In addition, when the humidity is high, the volatilization of solvent in the film is prevented, which will affect the curing quality of the paint film, so the humidity in the curing furnace is required to be low. When epoxy resin (containing fatty ester), alkyd resin and melamine resin are used, the acid gas (hydrogen peroxide, sulfur dioxide, carbon dioxide) in the furnace will react with each other on the surface of the coating, resulting in wrinkle and deep crack. Curing process is a key process in color coating production. The control of temperature, time and temperature rise curve of steel plate directly affects the T-bend, pencil hardness, gloss, wear resistance, solvent resistance and other properties of color coated plate, and has different effects on color difference of different color coatings. In the actual production process, these factors will have a comprehensive effect on the product, increasing the difficulty of analysis and adjustment. In addition, due to the difference of process layout and coating system used in each production line, it is necessary to gradually explore the law in production and establish a certain corresponding relationship, so as to better control the quality of products. In the baking process, the temperature of the steel plate increases gradually, which causes the solvent in the coating to volatilize and gradually crosslink and solidify completely.Because the temperature of each section of the curing furnace can be controlled separately, the strip steel can finally reach the PMT value through different heating curves. However, the temperature of the first and second sections of the furnace is usually controlled to be slightly lower, so that the solvent in the paint film can be fully volatilized before the film is cured. If the temperature is raised too fast, the solvent in the coating overflows too quickly, or the solvent in the paint film does not volatilize in time, the paint film has solidified, which will cause defects such as bubbles on the surface. In the third and fourth sections of the furnace, the temperature of the strip steel is slightly higher than the curing temperature of the coating. When the strip enters the third section, the solvent has evaporated and the film begins to solidify. At this time, the main defects of the coating, such as high wind speed, will accelerate the formation of chemical wrinkle. Color difference is a special performance index of color coated board. The color difference between coating product and standard board is expressed by $e in CIE standard color system. The influence of curing temperature on color difference is different. For most coatings such as white gray and sea blue, the color difference is basically stable within a certain temperature range (usually 224 ~ 241 E). For the sensitive scarlet, the curing temperature has a great influence on the color difference. This is because organic pigment is usually added to the scarlet paint, which has poor stability and is sensitive to temperature. Therefore, it is necessary to strictly control the curing temperature in the production of scarlet paint.