Dilute hydrochloric acid. Be careful not to soak rusty things in it for too long, otherwise after removing the surface rust, the substances inside will also react. For example, after removing the rust, it will react with the iron using sandblasting. Shot blasting is also possible, see the following instructions for details: 1. Small pneumatic or electric rust removal. It is mainly powered by electricity or compressed air, equipped with appropriate rust removal devices, and performs reciprocating or rotating motion to adapt to 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. They are semi-mechanized equipment. The tools are lightweight and maneuverable, and can remove rust more thoroughly. , old coatings, etc., the coating can be roughened, and the efficiency is much higher than manual rust removal, up to 1~2m2/h, but the oxide scale cannot be removed, the surface roughness is small, and high-quality surface treatment quality cannot be achieved. , the work efficiency is lower than that of spray treatment. It can be used in any position, especially in ship repair process. 2. Shot blasting (sand) rust removal. It is mainly composed of particle jet erosion to achieve surface cleanliness and appropriate roughness. The equipment includes open shot blasting (sand) rust remover, closed shot blasting (sand chamber), and vacuum shot blasting (sand) machine. Open shot blasting (sand) machines are widely used and can more thoroughly remove all impurities on the metal surface, such as oxide scale, rust and old paint films. The rust removal efficiency is high at 4~5m2/h, the mechanical level is high, and the rust removal quality is high. good. However, since abrasives generally cannot be recycled, they will have an impact on other operations and make cleaning the site troublesome. Therefore, the environmental pollution is serious, and its use has been gradually restricted recently. 3. High-pressure water abrasive rust removal. The impact of high-pressure water jets (plus the grinding effect of abrasives) and the action of water skids are used to destroy the adhesion of rust and coating to steel plates. Its characteristics are no dust pollution, no damage to the steel plate, greatly improving the rust removal efficiency, which can reach more than 15m2/h, and the rust removal quality is good. However, the steel plate after rust removal is easy to rust back, so it must be coated with special wet rust removal paint, which has a great impact on the coating of general performance paint. 4. Shot blasting to remove rust. Shot blasting uses a high-speed rotating impeller to throw abrasives onto the steel surface to achieve the purpose of rust removal. It is a relatively advanced mechanical processing method for rust removal of ship hull steel. It not only has high production efficiency, but also is low-cost and automated. It has a high degree of efficiency and can realize assembly line operation with less environmental pollution, but it can only be operated indoors. (3) Chemical rust removal is mainly a rust removal method that uses acid to react with metal oxides to remove rust products on the metal surface. It is commonly known as pickling and rust removal, and can only be operated in the workshop