In the process of pipeline anti-corrosion construction for oil and gas pipelines, the surface treatment of straight seam steel pipes is one of the key factors determining the service life of the pipeline anti-corrosion coating. It is the premise for the anti-corrosion coating to be firmly bonded to the straight seam steel pipe. According to research by professional institutions, the service life of the anti-corrosion coating is not only determined by the type of coating, the quality of the coating application, and the construction environment, but also by the surface treatment of the straight seam steel pipe, which accounts for about 50% of the influence. Therefore, strict compliance with the requirements for the surface treatment of anti-corrosion coatings should be strictly enforced, and continuous improvements should be made in the surface treatment methods for straight seam steel pipes.
ASME B36.10 A53 GR.B straight seam steel pipes
The main methods of removing rust from straight seam steel pipes are as follows:
1. Cleaning
The use of solvents and emulsions to clean the steel surface to remove oil,grease,dust,lubricants and similar organic matter,but it can not remove the rust,oxide,welding,etc,on the steel surface.So it is only used as an auxiliary means in the anti-government operation.
2. Pickling
Generally,chemical and electrolytic methods are used for pickling treatment and chemical pickling is only used for pipeline anti-corrosion which can remove the oxide,rust,and old coating.Although chemical cleaning can make the surface reach a certain degree of cleanliness and toughness its anchor pattern is shallow and it is easy to pollute the surrounding environment.
3. Tools to remove rust
Mainly use wire brush and other tools to polish the steel surface, which can remove loose oxide, rust, welding slag and so on. The rust removal of hand tools can reach Sa2 level, and the rust removal of power tools can reach Sa3 level. If the steel surface is firmly attached to the oxide scale, the rust removal effect of the tool is not ideal, and the anchor grain depth required for anti-corrosion construction is not reached.
4. Sandblasting removal
Jet rust removal is driven by a high-power motor jet blade high-speed rotation, so that steel balls, steel sand, iron wire segments, minerals and other abrades in the motor under the action of powerful centrifugal force on the surface of the straight seam steel pipe spraying treatment, not only can completely remove oxides, rust and dirt, and straight seam steel pipe in the abrasive impact and friction force, but also to achieve the required uniform roughness.
After spraying, not only can the physical adsorption effect of the pipe surface be expanded, but also the mechanical adhesion between the anti-corrosion layer and the pipe surface can be enhanced. Therefore, jet rust removal is an ideal way for pipeline corrosion protection.
