Pay attention to rust prevention during daily storage of high-pressure boiler tubes, because most companies store them outside the factory, which is easy to get damp and rust.
Basic methods for rust removal of high-pressure boiler tubes:
1. Cleaning: Use solvents and emulsions to clean the surface of high-pressure boiler tubes to remove oil, grease, dust, lubricants and similar organic matter, but it cannot remove rust, scale, welding flux, etc. on the surface of high-pressure boiler tubes, so it is only used as an auxiliary means in anti-corrosion production.
2. Tool rust removal: Mainly use tools such as wire brushes to grind the surface of high-pressure boiler tubes, which can remove loose or raised scale, rust, welding slag, etc. Manual tool rust removal can reach Sa2 level, and power tool rust removal can reach Sa3 level. If the surface of the high-pressure boiler tube is firmly attached to the iron oxide scale, the tool rust removal effect is not ideal, and the anchor pattern depth required for anti-corrosion construction cannot be achieved.
3. Pickling: Generally, chemical and electrolytic methods are used for pickling. Pipeline anti-corrosion only uses chemical pickling, which can remove scale, rust, and old coatings. Sometimes it can be used as a re-treatment after sandblasting. Although chemical cleaning can make the surface reach a certain degree of cleanliness and roughness, its anchor pattern is shallow and it is easy to pollute the environment.
4. Spraying (blasting) rust removal: Spraying (blasting) rust removal is to use a high-power motor to drive the spray (blasting) blade to rotate at high speed, so that steel sand, steel shot, wire segments, minerals and other abrasives are sprayed (blasted) on the surface of the steel pipe under the action of centrifugal force. It can not only completely remove rust, oxides and dirt, but also the high-pressure boiler tube can achieve the required uniform roughness under the violent impact and friction of the abrasive.
After spraying (blasting) rust removal, it can not only expand the physical adsorption effect of the pipe surface, but also enhance the mechanical adhesion between the anti-corrosion layer and the pipe surface. Therefore, spraying (blasting) rust removal is an ideal rust removal method for pipeline anti-corrosion. Generally speaking, shot peening (sand) rust removal is mainly used for the inner surface treatment of high-pressure boiler tubes, and shot blasting (sand) rust removal is mainly used for the outer surface treatment of tubes. Several issues should be noted when using shot blasting (blasting) rust removal.
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