To improve the service life of oil and gas pipelines, surface treatment is usually carried out to facilitate the firm combination of thick-walled steel pipes and anti-corrosion layers. Common treatment methods are: cleaning, tool de-rusting, pickling, spray shot blasting, and de-rusting.
1. Pickling on the surface of
thick-walled steel pipe: common pickling methods include chemical methods and electrolytic methods. However, only chemical pickling is used for pipeline corrosion protection. Chemical pickling can achieve the cleanliness and roughness of the steel pipe surface, which is convenient for subsequent anchor lines. Usually as a reprocessing after shot peening (sand).
2. Shot peening and de-rusting of thick-walled steel pipe: The high-power motor drives the blades to rotate at high speed so that abrasives such as steel sand, steel shot, iron wire segment, minerals, etc. are sprayed and projected onto the surface of the steel pipe. The effect of centrifugal force. On the one hand, rust, oxygen reactants, and dirt, on the other hand, the steel pipe reaches the required uniform roughness under the severe impact and friction of abrasives.
3. Cleaning of thick-walled steel pipes: Grease, dust, lubricants, and organic matter attached to the surface of thick-walled steel pipes are usually cleaned with solvents and emulsions. However, the rust, oxygen reaction skin, welding slag, etc. on the surface of the steel pipe cannot be removed, and other treatment methods are required.
4. Use tools to de-rust thick-walled steel pipes: steel wire brushes can be used to clean and polish the oxygen reaction skin, rust, welding slag, and other surfaces on the steel pipe surface. There are two types of rust removal tools, manual and electric. The de-rusting of hand tools can reach the Sa2 level, and the de-rusting of electric tools can reach the Sa3 level. If there is a layer of skin that is particularly reactive to oxygen attached to the surface of the steel pipe, it may not be cleaned with the help of tools, and other methods need to be found.
Among the four surface treatment methods for thick-walled steel pipes, shot blasting is the ideal method for pipe rust removal. Generally, shot blasting is mainly used for the inner surface treatment of steel pipes, and shot blasting is mainly used for the outer surface treatment of steel pipes.
The main processing method of thick-walled steel pipes is rolling, which is a pressure process in which steel metal blanks pass through the gap (various shapes) of a pair of rotating rolls. Due to the compression of the rolls, the cross-section of the material is reduced and the length of the thick-walled steel pipe is increased. The production method is a common production method for the production of steel, mainly used for the production of profiles, plates, and pipes. Divided into cold rolling and hot rolling. Forging steel: It is a pressure processing method that uses the reciprocating impact force of the forging hammer or the pressure of the press to make the blank into the shape and size we need. It is generally divided into free-forging and die-forging seamless steel pipes. Steel pipes are still an indispensable material for various conventional weapons. Barrels, gun barrels, etc. must be made of steel pipes. Steel pipes can be divided into round pipes and special-shaped pipes according to the shape of the cross-sectional area. Because under the premise that the circumferences are equal, the area of the circle is large, and more fluid can be transported with a round tube. In addition, the circular section of the thick-walled steel pipe bears relatively uniform force when it bears internal or external radial pressure. Therefore, most thick-walled steel pipes are round pipes. Steel pipes have a hollow cross-section and are widely used as pipes for conveying fluids, such as pipes for conveying oil, natural gas, gas, water, and certain solid materials. Compared with solid steel such as round steel, seamless steel pipes are lighter in weight under the same bending and torsional strength. Thick-walled steel pipe is an economical cross-section steel that is widely used in the manufacture of structural and mechanical parts, such as oil drill pipes, transmission shafts for automobiles, bicycle frames, and steel scaffolding for building construction.
