Pre-painting surface treatment knowledge

Pre-painting surface treatment knowledge

Common surface treatment methods are:
Manual treatment: such as scraper, wire brush or grinding wheel. The rust and scale on the surface of the workpiece can be removed by hand, but the manual treatment is labor intensive, the production efficiency is low, the quality is poor, and the cleaning is not thorough.
Chemical treatment: It mainly uses acidic or alkaline solution to chemically react with oxides and oil stains on the surface of the workpiece to dissolve it in acidic or alkaline solution to achieve the purpose of removing rust scale and oil stain on the surface of the workpiece. The chemical treatment is suitable for the cleaning of thin plates, but the disadvantage is that if the time is not properly controlled, even if a corrosion inhibitor is added, the steel can be over-etched. For more complicated structural parts and perforated parts, after acid pickling by acidic solution, the residual acid immersed in the gap or cavity is difficult to be completely removed. If improperly treated, it will become a hidden danger of corrosion after the workpiece, and the chemical is volatile, and the cost is low. High, the chemical discharge after treatment is difficult, if not handled properly, it will cause serious pollution to the environment. As people's environmental awareness increases, this treatment is being replaced by mechanical treatment.
Mechanical treatment: mainly includes shot blasting and shot peening. Shot blasting is a method of accelerating the projectile by centrifugal force and projecting it to the workpiece for rust removal. However, the flexibility of shot blasting is poor, limited by the site, and there is some blindness when cleaning the workpiece. It is easy to produce a dead angle that cannot be cleaned on the inner surface of the workpiece. The structure of the equipment is complicated, and there are many wearing parts, especially the parts such as blades are worn out quickly, the maintenance man-hours are many, the cost is high, and the one-time investment is large.
Shot peening is divided into shot peening and sand blasting. The surface treatment is carried out by shot peening, and the impact force is large, and the cleaning effect is obvious. However, the treatment of the sheet metal workpiece by the shot peening is easy to deform the workpiece, and the steel shot hits the surface of the workpiece (whether shot blasting or shot peening) to deform the metal substrate. Since Fe3O4 and Fe2O3 have no plasticity, the stripping after peeling, and the oil film and The substrate is deformed together, so the shot blasting and shot peening cannot completely remove the oil stain on the workpiece with oil stains. In the existing surface treatment method of the workpiece, the best cleaning effect is blast cleaning. Sand blasting is suitable for cleaning surfaces with high surface requirements. However, the current general blasting equipment in China is composed of original bulky sand transporting machinery such as hinges, scrapers and bucket elevators. The user needs to build a deep pit and make a waterproof layer to install the machine. The construction cost is high, the maintenance workload and maintenance cost are great, and a large amount of dust can not be removed during the sand blasting process, which seriously affects the health of the operator and pollutes the environment. .
With the continuous improvement of science and technology, with the constant demand for product quality, with the high-tech equipment continuously applied in the enterprise, with the improvement of people's environmental awareness, the strict requirements of the environmental protection department, the control of dust pollution and noise The environment is no longer a matter of urgency. The competition of enterprises is becoming more and more fierce, so how to gain advantages in the fierce competition becomes the key to determining the development of the enterprise. The facts tell us that strict production links are the premise to ensure the quality of enterprise products. It is the responsibility of each of us to control environmental pollution.