Degreasing: Use chemical solvents or alkaline solutions to clean the surface of the steel plates, removing contaminants such as oil and grease that the steel plates may have picked up during processing and storage, so as to ensure the adhesion of the subsequent coating to the surface of the steel plates.

Rust Removal: Remove rust and oxide scale on the surface of the steel plates through methods like shot blasting, sandblasting or chemical rust removal, making the surface of the steel plates reach a certain roughness, increasing the contact area between the paint and the steel plates, and improving the adhesion and anti-corrosion performance of the coating.

Phosphating Treatment: Conduct phosphating treatment on the steel plates that have undergone degreasing and rust removal treatment, forming a phosphate chemical conversion film on the surface of the steel plates to further improve the corrosion resistance of the steel plates and the adhesion of the paint.

Paint Mixing: According to the process requirements and the usage environment of the steel plates, select appropriate primer varieties, and mix and blend the paint, diluents, etc. in accordance with the specified proportions. Stir evenly to adjust the performance of the paint such as viscosity and drying speed to make it meet the spraying requirements.

Spraying: Use spray guns or automatic spraying equipment to evenly spray the mixed primer onto the surface of the steel plates. During the spraying process, control the pressure, distance, angle and moving speed of the spray gun to ensure that the primer coating has a uniform thickness and is free from defects such as missed spraying, sagging and blistering.

Drying: After spraying the primer, send the steel plates into the drying chamber for drying. The drying temperature and time are determined according to the types and properties of the primer. Generally, the temperature ranges from 60 °C to 150 °C, and the drying time ranges from 15 to 60 minutes, enabling the primer to dry and solidify quickly and form a bottom coating with a certain hardness and adhesion.

Grinding: If it is necessary to increase the thickness and fullness of the coating, after the primer has dried, grind the surface of the primer. Use tools such as sandpaper or grinding machines to grind the uneven areas and particles on the surface of the primer to make it smooth, providing a good surface basis for the spraying of the intermediate coating.

Intermediate Paint Spraying: According to a process similar to that of primer spraying, spray the intermediate paint onto the surface of the ground primer to further increase the thickness and anti-corrosion performance of the coating. After the intermediate paint has dried, it can be ground and sprayed again as required to achieve the desired coating effect.

Paint Mixing Again: According to the design requirements and customer needs, select appropriate finish coat colors and properties, and conduct paint mixing operations to ensure that the quality and performance of the finish coat meet the spraying standards.

Fine Spraying: Use more precise spraying equipment and techniques to evenly and meticulously spray the finish coat onto the surface of the steel plates. The spraying quality of the finish coat directly affects the appearance and weather resistance of the steel plates. Therefore, strictly control the spraying parameters to ensure that the finish coat has good glossiness, uniform color and integrity.

Leveling and Drying: After spraying the finish coat, let the steel plates level naturally under certain environmental conditions for a period of time to make the surface of the finish coat smoother and flatter. Then send the steel plates into the drying chamber for drying. Adjust the drying conditions according to the characteristics of the finish coat to make the finish coat fully dry and solidify and form the final protective and decorative coating.

Appearance Inspection: Conduct a comprehensive appearance inspection on the painted steel plates to check whether there are defects such as sagging, orange peel, blisters, pinholes and missed spraying on the surface of the coating, whether the color is uniform, and whether the glossiness meets the requirements.

Thickness Detection: Use coating thickness gauges and other tools to detect whether the thickness of the coating meets the design standards. Different usage environments and requirements have different regulations on the coating thickness, ensuring that the coating thickness is within the allowable tolerance range.

Adhesion Test: Use methods such as the cross-cut test and the pull-off method to detect the adhesion between the coating and the surface of the steel plates to ensure that the coating will not peel off or flake during use.

Performance Testing (Optional): According to the specific uses of the steel plates and customer requirements, some other performance tests may also be required, such as corrosion resistance tests, weather resistance tests, abrasion resistance tests, etc., to verify whether the coating meets various performance indicators under actual use conditions.

Cooling and Cleaning: After the inspected and qualified steel plates come out of the drying chamber or inspection area, first conduct natural cooling or forced cooling to lower their temperature to room temperature. Then clean the surface of the steel plates to remove dust, debris and other substances that may be attached.

Packaging: Package the steel plates according to customer needs and transportation requirements. Packaging methods can include wrapping with plastic film, bundling, adding corner protectors, etc., to protect the painted steel plates from damage during transportation and storage.

Warehousing or Shipment: Package the steel plates with the specified markings and batches for warehousing and storage, waiting to be shipped to customers; or directly load them onto vehicles for shipment and deliver them to users.