Normal method of metal surface treatment
First, manual processing: such as scraper, wire brush or grinding wheel. The rust and oxide on the surface of the workpiece can be removed by hand, but the manual treatment has high labor intensity, low production efficiency, poor quality and incomplete cleaning.
For more complex structural parts and parts with holes, after acid solution pickling, the residual acid immersed in the gaps or holes is difficult to completely remove, if improper treatment, will become a hidden danger of corrosion of the workpiece, and chemicals volatile, high cost, chemical discharge after treatment is difficult, if improper treatment, will cause serious pollution to the environment.
With the improvement of people's environmental awareness, this treatment method is being replaced by mechanical treatment. Shot blasting is divided into shot blasting and sand blasting, both use metal abrasives, like steel shot or Steel Grit or low carbon steel shot etc. Surface treatment with shot peening has great impact and obvious cleaning effect.
However, the treatment of the sheet workpiece is easy to deform the workpiece, and the steel shot or steel grit hits the surface of the workpiece (whether shot blasting or shot blasting) to deform the metal substrate, because Fe3O4 and Fe2O3 are not plastic, broken off, and the oil film deforms with the substrate, so for the workpiece with oil, shot blasting and shot blasting can not completely remove the oil.
Second, mechanical treatment method: mainly includes shot blasting method and shot peening method. Shot blasting method is a method of using centrifugal force with steel shots or steel grits to accelerate the projectile and throw it to the workpiece for rust cleaning. However, the flexibility of shot blasting is poor, limited by the site, some blindness when cleaning the workpiece, and it is easy to produce dead corners on the inner surface of the workpiece.
The equipment structure is complex, the wearing parts are many, especially the parts such as blades wear quickly, the maintenance hours are many, the cost is high, and the one-time investment is large.
Third, chemical treatment: mainly the use of acid or alkaline solution and the workpiece surface of the oxide and oil chemical reaction, so that it dissolved in the acid or alkaline solution, in order to remove the workpiece surface rust oxide and oil purposes. Chemical treatment is suitable for cleaning sheet parts, but the disadvantage is that if the time is not properly controlled, even if the corrosion inhibitor is added, the steel can produce overcorrosion.
