There are five main methods of derusting carbon steel pipes (CS Pipes): manual treatment, mechanical treatment, sandblasting, shot peening, chemical treatment and flame treatment.
(1) Manual processing
Manual treatment mainly uses spatula, wire brush, emery cloth, broken steel saw blade and other tools to remove rust by manual knocking, shoveling, scraping, brushing and sanding. This is the traditional method of rust removal for painters, and it is also the easiest method. , without any environmental and construction conditions restrictions, but due to the poor efficiency and effect, only a small range of rust removal can be applied.
(2) Mechanical derusting method
The mechanical rust removal method mainly uses some electric and pneumatic tools to achieve the purpose of removing rust. Commonly used electric tools such as electric brushes and electric grinding wheels; pneumatic tools such as pneumatic brushes. Electric brushes and pneumatic brushes use the rotation of a special round wire brush to remove rust or scale by impact and friction. Especially for carbon steel pipe surface rust, the effect is better, but it is difficult to remove deep rust spots. The electric grinding wheel is actually a portable grinder, which can be moved freely in the hand. The high-speed rotation of the grinding wheel is used to remove rust. The effect is better, especially for deeper rust spots. It has high work efficiency, good construction quality, and is easy to use.
(3) Sand blasting and shot peening treatment
Shot blasting treatment can directly process steel raw materials, replace the pretreatment line to pretreat the raw materials without the shot blasting pretreatment line, or pretreat the ultra-thick plates that are difficult to handle in the pretreatment line, and then match it with manual coating Shop primer. However, the shot peening treatment is mainly to carry out surface treatment on the sections, outfitting parts and structural parts composed of steel materials that have not been pretreated by raw materials, and it is equipped with hand-painted anti-rust paint. In addition, shot peening is also an important process for secondary rust removal. Shot peening is generally carried out in the shot blasting room. The abrasive in the shot peening cylinder is driven by compressed air, and shot to the surface of the treated carbon steel pipe and steel through the shot peening hose and nozzle.
Sand blasting and shot peening are ideal rust removal methods. Sandblasting and rust removal requires certain operating skills, and requires a special sandblasting room and sandblasting device, but care must be taken during operation not to penetrate the metal skin.
(4) Flame treatment method
The flame treatment method is to use a gas torch to burn a small amount of deep rust spots that are difficult to remove by hand, and let the high temperature change the chemical composition of the rust oxides to achieve the purpose of rust removal. When using this method, care must be taken not to burn through the metal surface and to prevent thermal deformation of a large area of the surface.
(5) Chemical treatment method
The chemical treatment method is actually a pickling and rust removal method, which uses an acidic solution to chemically react with metal oxides (rust) to generate salts, which are separated from the metal surface. Commonly used acid solutions are: sulfuric acid, hydrochloric acid, nitric acid, phosphoric acid.
During the operation, the acidic solution is applied to the rust part of the metal to allow it to slowly react with the rust and remove it. After the rust is removed, it should be rinsed with clean water, and neutralized with a weak alkali solution, and then the pickled metal surface must be roughened or phosphating, mainly to increase the adhesion between the metal surface and the primer. When diluting concentrated sulfuric acid, slowly pour the sulfuric acid into the water in the container, and keep stirring, do not do the opposite, so as not to splash the sulfuric acid solution and hurt people.
Tips: In the application of submarine oil and gas pipeline engineering, oil drills and petrochemical companies use welded pipes for gasoline, kerosene, diesel and other pipelines. ERW welded pipes are safe and economical.