The surface of the steel drum is most likely to be oxidized and corroded prior to painting. The scale and rust on the surface of the drum are mainly ferrous oxide, iron oxide, iron oxide hydrate, triiron tetroxide and the like. Before the drum coating, if the scale and rust on the surface are not removed, the adhesion, decorative and service life of the paint film on the drum surface will be affected. Because the rust structure is loose, the surface of the steel drum is not firmly attached, and it easily falls off with the coating. The oxide scale will generate trihydrate iron trioxide under the effect of hydrazine, and the volume will increase to cause foaming, cracking and shedding of the paint film. The oxide under the paint film and the corrosion of the metal iron in the steel drum are the cathodes in the battery. It promotes the continued corrosion of the metal on the surface of the drum, and the coating is quickly destroyed.
The method of removing rust on the surface of steel drums falls into two major categories: chemical methods and mechanical methods.
Chemical rust removal is the use of chemical melon or electrochemical melon to dissolve the general rust, oxide scale and various corrosion products from the surface of the steel drum without affecting the metal of the steel drum base. The most commonly used method of chemical rust removal is pickling, which uses organic or inorganic acids to cause the oxide and yellow rust on the surface of the drum to fold off the surface of the drum.
Mechanical rust removal is the use of friction, hammering, erosion and other mechanical forces, so that the abrasive particles on the surface of the drum to remove rust, high-temperature oxide and other dirt. The most commonly used mechanical rust removal method for steel drum enterprises is manual grinding. The mechanical polishing is used to remove rust. It is a simple tool to remove rust with human power. The method is simple and easy, but the labor intensity is large, the production efficiency is low, and the quality of rust removal is poor. Generally only loose or lighter rust can be removed.
Steel barrel outer surface derusting machine and inner surface derusting machine