Because of the large mass of spiral welded pipes, they must be stacked outdoors, but it is difficult to avoid being exposed to the sun and rain, so the problem of rust has been plaguing the storage time and conditions of spiral welded pipes. Therefore, it is necessary to provide a comprehensive answer to the knowledge of rust prevention for spiral welded pipes.
The cleaning and preheating of spiral welded pipes can remove loose or raised oxidized skin, rust, and weld slag. The rust removal by hand tools can reach Sa2 level, and the rust removal by power tools can reach Sa3 level, but if the steel surface is firmly coated with oxidized iron, the effect of rust removal by tools is not satisfactory, and the depth of anchor pattern required for anti-corrosion construction cannot be achieved.
Acid cleaning uses solvents and emulsions to clean the surface of welded steel pipes (welded tubes) for low pressure fluid transmission to remove oil, grease, dust, lubricants and similar organic substances, but it cannot remove rust, oxidized skin, welding flux, etc. on the steel surface, so it is only used as an auxiliary means in the production of corrosion prevention.
Chemical and electrolytic pickling are generally used, but only chemical pickling is used to remove oxidation, rust, and old coatings, and is sometimes used as a retreatment after spray* rust removal. Although chemical cleaning can achieve a certain degree of surface cleanliness and roughness, it has a shallow anchor pattern and is prone to pollution of the spiral welded pipe stacking environment.
The proper use of tools for rusted pipe *processing ensures that the pipe will remain in service for a long time and create more production benefits.