Thick-walled steel pipes have a wide variety of steel types and specifications, and their performance requirements are also various. All of these should be differentiated as user requirements or working conditions change. Usually, steel pipe products are classified according to cross-sectional shape, production method, pipe material, connection method, coating characteristics, and use. Thick-walled steel pipes can be divided into round steel pipes and special-shaped steel pipes according to their cross-sectional shape.
Special-shaped thick-walled steel pipes refer to various steel pipes with non-circular cross-sections, including square pipes, rectangular pipes, elliptical pipes, flat elliptical pipes, semicircular pipes, hexagonal pipes, hexagonal inner pipes, unequal hexagonal pipes, equilateral triangle pipes, pentagonal plum blossom pipes, octagonal pipes, convex pipes, and double convex pipes. Double concave tube, multi-concave tube, melon seed tube, flat tube, diamond tube, star tube, parallelogram tube, ribbed tube, drop-shaped tube, inner fin tube, twisted tube, B-type tube, D-type tube, multi-layer tube, etc.
Thick-walled steel pipes are divided into equal-section steel pipes and variable-section steel pipes according to the longitudinal section shape. Variable-section (or variable-section) steel pipes refer to steel pipes whose cross-sectional shape, inner and outer diameters, and wall thicknesses along the length of the pipe undergo periodic or non-periodic changes. They mainly include: outer conical tubes, inner conical tubes, outer step tubes, inner step tubes, periodic section tubes, corrugated tubes, spiral tubes, steel pipes with heat sinks gun barrels with double lines, etc.
To increase the life of oil and gas pipelines, surface treatment is usually required to facilitate the firm combination of thick-walled steel pipes and anti-corrosion layers. Common treatment methods include: cleaning, tool rust removal, pickling, and shot blasting.
1. Surface pickling of straight seam steel pipes: Common pickling methods include chemical and electrolytic methods. However, chemical pickling is only used for pipeline anti-corrosion. Chemical pickling can achieve the cleanliness and roughness of the steel pipe surface, which is convenient for subsequent anchor lines. It is usually used as a reprocessing after shot peening (sand).
2. Shot blasting and rust removal: The high-power motor drives the blades to rotate at high speed so that abrasives such as steel sand, steel shot, wire segments, minerals, etc. are sprayed on the surface of the steel pipe under the action of centrifugal force. On the one hand, rust, oxygen reactants, and dirt are removed, and on the other hand, the steel pipe is violently impacted and frictional by the abrasive to achieve the required uniform roughness.
3. Thick-walled steel pipe cleaning: Grease, dust, lubricants, and organic matter adhered to the surface of thick-walled steel pipes are usually cleaned with solvents and emulsions. However, the rust, oxygen reaction skin, and welding slag on the surface of the steel pipe cannot be removed, and other treatment methods are required.
4. Use tools to remove rust from straight seam steel pipes: The oxygen reaction scale, rust, and welding slag on the steel pipe surface can be cleaned and polished with a wire brush. There are two types of tool rust removal: manual and power. Manual tool rust removal can reach the Sa2 level, and power tool rust removal can reach the Sa3 level. If the surface of the steel pipe is attached to a particularly strong oxygen reaction scale, 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 treatment method for pipeline 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 for thick-walled steel pipes is rolling, which is a pressure processing method in which the steel metal billet passes through the gap (various shapes) of a pair of rotating rollers. Due to the compression of the rollers, the material cross-section is reduced and the length of the thick-walled steel pipe is increased. This is a common production method for steel, mainly used to produce steel profiles, plates, and pipes. It is divided into cold rolling and hot rolling. Forged steel: A pressure processing method that uses the reciprocating impact force of the forging hammer or the pressure of the press to change the blank into the shape and size we need. Generally divided into free forging and die-forging seamless steel pipes Steel pipes are still an indispensable material for various conventional weapons. Gun barrels, cannon barrels, etc. are all made of steel pipes. Steel pipes can be divided into round pipes and special-shaped pipes according to the different cross-sectional area shapes. Because the area of the circle is large under the premise of equal circumference, more fluids can be transported by round pipes.
In addition, the circular cross-section of thick-walled steel pipes is more evenly stressed when subjected to internal or external radial pressure. Therefore, most of the thick-walled steel pipes are round pipes. Steel pipes have hollow cross-sections and are widely used as pipelines for conveying fluids, such as pipelines for conveying oil, natural gas, coal gas, water, and certain solid materials. Compared with solid steel products such as round steel, seamless steel pipes are lighter in weight when the bending and torsional strength are the same. Thick-walled steel pipes are an economical cross-section steel product and are widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes, automobile drive shafts, bicycle racks, and steel scaffolding for construction.
Post time: Dec-30-2024