Manual Rust Removal
Tools for manual rust removal include hammer, spatula, scraper, wire brush, etc. Generally thick rust spots are loosened with a hammer and then removed with a spatula. The labor intensity is high, the rust removal efficiency is low, generally 0.2~0.5m2/h, the environment is bad, it is difficult to remove the oxide scale and other dirt, the rust removal effect is not good, and it is difficult to achieve the specified cleanliness and roughness. Fang Hanhe replaced by chemical methods. However, this method is often used in the process of repairing ships, especially for repairing local defects; for parts that are difficult to reach by mechanical rust removal, such as small cabins, corners and edges of section steel, etc., manual rust removal is often used.

Mechanical Derusting
There are many tools and techniques for mechanical rust removal, of which the following four are the main ones:
1. Small air or electric rust removal. It is mainly powered by electricity or compressed air, equipped with a suitable rust removal device, and performs reciprocating or rotating motion to meet the rust removal requirements of various occasions. Such as angle grinders, wire brushes, pneumatic needle beam rust removers, pneumatic rust hammers, toothed rotary rust removers, etc., are semi-mechanized equipment with light tools and high mobility, which can completely remove rust. , Old coating, etc., can roughen the coating, the efficiency is greatly improved than manual rust removal, up to 1~2m2/h, but can not remove the oxide scale, the surface roughness is small, and the high-quality surface treatment cannot be achieved The quality and efficiency are lower than spray treatment. It can be used in any part, especially in the process of ship repairing.
2. Shot blasting (sand) to remove rust. It is mainly composed of particle jet erosion to achieve surface cleanliness and suitable roughness. The equipment includes open shot blasting (sand) rust remover, closed shot blasting (sand chamber), and vacuum shot blasting (sand) machine. The open shot blasting (sand) machine is widely used, and can more thoroughly remove all impurities on the metal surface, such as oxide scale, rust and old paint film. The rust removal efficiency is 4~5m2/h, the mechanical degree is high, and the rust removal quality it is good. But because abrasives generally cannot be recycled, it affects other homework and is troublesome to clean up the site. Therefore, the environmental pollution is serious, and its use has been gradually restricted recently.
3. High pressure water abrasive for rust removal. The impact of high-pressure water jets (plus the grinding action of abrasives) and the action of water skids are used to destroy the adhesion of rust and coating to the steel plate. It is characterized by no dust pollution, no damage to the steel plate, greatly improving the rust removal efficiency, up to 15m2/h, and good rust removal quality. However, the steel plate after derusting is easy to return to rust, and special wet derusting paint must be painted, which has a greater impact on the coating of general functional paint.
4. Shot blasting to remove rust. Shot blasting rust removal is the use of high-speed rotating impellers to throw abrasives on the surface of steel to achieve the purpose of rust removal. It is a mechanical treatment method that improves the rust of ship hull steel. It not only has high production efficiency, but also low cost. , High degree of automation, can realize assembly line operation, less environmental pollution, but only operate indoors.

Chemical Rust Removal
A rust removal method that mainly uses acid to react with metal oxides to remove the rust products on the metal surface, that is, the so-called pickling and rust removal, can only be operated in the workshop.