Detailed explanation of the surface treatment and processing methods of thick-walled steel pipes

Detailed explanation of the surface treatment and processing methods of thick-walled steel pipes Thick-walled steel pipes come in a wide variety of steel types and specifications, and their performance requirements are also diverse. 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-making material, connection method, coating characteristics and uses, etc. Thick-walled steel pipes can be divided into round steel pipes and special-shaped steel pipes according to their cross-sectional shapes. 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, semi-circular pipes, hexagonal pipes, hexagonal inner circular pipes, and unequal hexagons. tube, equilateral triangle tube, pentagonal plum blossom tube, octagonal tube, convex tube, biconvex tube. Double concave tube, multi-concave tube, melon-shaped tube, flat tube, rhombus tube, star tube, parallelogram tube, ribbed tube, drop tube, inner fin tube, twisted tube, B-type tube, D Type tubes, multi-layer tubes, etc. Thick-walled steel pipes are further divided into constant-section steel pipes and variable-section steel pipes according to their longitudinal section shapes. Variable cross-section (or variable cross-section) steel pipes refer to steel pipes whose cross-sectional shape, internal and external diameters, and wall thickness change periodically or non-periodically along the length of the pipe. They mainly include outer tapered tube, inner tapered tube, outer stepped tube, inner stepped tube, periodic section tube, corrugated tube, spiral tube, steel tube with radiator, and gun barrel with multiple lines. To extend the service 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 electrolysis. However, only chemical pickling is used for the anti-corrosion of pipelines. Chemical pickling can achieve the highest cleanliness and roughness on the surface of the steel pipe, which facilitates subsequent anchor lines. Usually used as a post-processing after shot blasting (sand). 2. Shot blasting and rust removal: A high-power motor drives the blades to rotate at high speed so that abrasives such as steel sand, steel shots, iron wire segments, and minerals are sprayed on the surface of the steel pipe under the action of centrifugal force. On the one hand, rust, oxygen reactants, and dirt, on the other hand, the steel pipe achieves the required uniform roughness under the action of the violent impact and friction of the abrasive. 3. Cleaning of thick-walled steel pipes: To remove grease, dust, lubricants, and organic matter adhered to the surface of thick-walled steel pipes, solvents, and emulsions are usually used to clean the surface. However, the rust, oxygen reaction skin, and welding slag on the surface of the steel pipe cannot be removed, and other treatment methods are needed. 4. Use tools to remove rust from straight seam steel pipes: To remove oxygen-reactive skin, rust, and welding slag on the surface of the steel pipe, a wire brush can be used to clean and polish the surface. There are two types of tool rust removal: manual and power. The rust removal of manual tools can reach the Sa2 level, and the rust removal of power tools can reach the Sa3 level. If there is a particularly strong oxygen reaction skin attached to the surface of the steel pipe, it may not be possible to remove the rust even with the help of tools, so 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 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. This is a pressure process in which the steel metal blank is passed through the gap of a pair of rotating rollers (in various shapes). Due to the compression of the rollers, the material cross-section is reduced and the length of the thick-walled steel pipe is increased. Method, this is a commonly used production method for the production of steel, mainly used to produce steel profiles, plates, and pipes. Divided into cold rolling and hot rolling. Forging steel: A pressure processing method that uses the reciprocating impact of a forging hammer or the pressure of a press to change the blank into the shape and size we require. Generally divided into free forging and die-forging seamless steel pipes, steel pipes are still an indispensable material for various conventional weapons. Gun barrels, barrels, etc. are all made of steel pipes. Steel pipes can be divided into round pipes and special-shaped pipes according to different cross-sectional areas and shapes. Because the circumferences are equal and the circle area is large, circular tubes can transport more fluid. In addition, the ring section of thick-walled steel pipes is relatively evenly stressed when it bears internal or external radial pressure. Therefore, the vast majority of thick-walled steel pipes are round pipes. Steel pipes have hollow sections and are widely used as pipelines for transporting fluids, such as pipelines for transporting oil, natural gas, coal gas, water, and certain solid materials. Compared with solid steel materials 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 economical cross-section steel and are widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipes and automobiles. Drive shafts, bicycle racks steel scaffolding used in construction, etc. Post time: Jan-16-2024