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What is the production process of Dacromet screws


(Substrate, degreasing, derusting, coating, preheating, curing, cooling )
Note: The above coating and curing process can be repeated
1. Degreasing: The surface of the workpiece with grease must be degreasing. There are generally three methods: organic solvent degreasing, water-based degreasing agent degreasing, and high-temperature carbonization degreasing. Whether the degreasing is complete and effective will directly affect the adhesion and corrosion resistance of the coating.
2. Derusting and deburring: It is strictly forbidden to directly coat the workpiece with rust or burrs, and must go through the derusting and deburring process. This process is best to use mechanical methods to avoid pickling to prevent hydrogen embrittlement, and pickling to remove rust , The corrosion resistance of Dacromet coating is affected by pickling.
3. Coating: The clean workpieces that have been degreasing and derusting must be coated as soon as possible by dipping, spraying, and brushing. When the workpiece is coated, the specific gravity, ph, viscosity, cr6 content, temperature and flow condition of the coating liquid will directly affect the coating effect of the workpiece and affect the performance of the coating. Therefore, during the coating process, the relationship between the temperature, the solution index and the speed of the centrifuge in the dip coating should be adjusted.
4. Pre-drying: Dacromet's wet film work piece must be pre-baked at a temperature of 120±20℃ for 10-15 minutes (according to the heat absorption of the work piece) as soon as possible to evaporate the water in the coating liquid and level it evenly.
5. Sintering: The pre-baked workpiece must be sintered at a high temperature of about 300°C, and the sintering time is 20-40 minutes (according to the heat absorption of the workpiece). The temperature can also be appropriately increased to shorten the sintering time.
6. Cooling: After the workpiece is sintered, it must be fully cooled by the cooling system for subsequent processing or finished product inspection.

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