The function of the pipeline is mainly to transport liquids or other solids. It can be said to be the most commonly used equipment in our lives. 3 treatment methods for pipeline anti-corrosion.

1. What are the treatment methods for pipeline anti-corrosion?

1. Pipeline external anti-corrosion design Petroleum asphalt is the oldest pipeline anti-corrosion layer, which is well used in most dry areas. At present, epoxy coal tar, zinc-rich coatings, etc. have replaced petroleum asphalt as anti-corrosion coatings for steel water pipelines, and epoxy coal tar series coatings have excellent anti-corrosion performance and low prices.

2. The anti-corrosion coating on the outer wall of the pipeline is evenly and densely applied on the surface of the rust-removed metal pipeline to isolate it from various corrosive media. It is one of the most basic methods for pipeline anti-corrosion. Since the 1970s, laying pipelines in harsh environments such as polar regions and oceans, and heating and transporting oil products to increase the temperature of the pipeline, have put forward more requirements on the performance of the coating.

3. Pipeline inner wall anti-corrosion coating Surface treatment of the inner wall of the pipe can ensure that the coating is firmly bonded to the pipe wall. Since the 1970s, the trend has been to use the same material for the inner and outer wall coatings of the pipe so that the inner and outer wall coatings can be carried out simultaneously. Before the pipeline is treated for corrosion, the surface of the pipeline substrate must be treated to remove moisture, oil, dirt, pollutants, rust and scale on the surface of the substrate. There are many methods for surface treatment, and manual rust removal, sandblasting or chemical rust removal are generally used. When removing rust manually, the quality standard should reach St3 level; when sandblasting or chemical rust removal, the quality standard should reach Sa2.5 level, and the surface roughness of 30 to 50µm is more appropriate. The treated surface should be primed within 4 hours.

2. What is the role of pipeline anti-corrosion?

1. Prevent the pipeline from being corroded by soil, air, medium, etc. Nowadays, pipelines are mostly used to transport gasoline, natural gas and other substances. These substances have a very large corrosive effect on the soil of the environment, and pipelines can effectively prevent the environment from being polluted by these substances, and greatly improve the transportation efficiency.

2. Pipeline anti-corrosion can prevent the leakage of natural gas, oil, etc., and has a very good protection and prevention effect on fire and the environment.

3. What are the precautions during pipeline anti-corrosion construction?

1. The ambient temperature should be higher than 5℃ and the air humidity should be lower than 80% during the construction of the anti-corrosion layer.

2. The diluent ratio is 5%, the glass cloth is pressed 20-25mm, and the overlap length of the cloth head is 100-150mm.

3. Anti-corrosion layer voltage inspection: ordinary level 2000V; reinforced level 2500V; extra reinforced level 3000V.

4. Anti-corrosion layer inspection: every 10km leakage point ≯5, use a low-voltage audio signal leak detector to measure.

The buried pipeline uses plastic-coated steel pipe for the transmission line tower, which is composed of towers connected by tower pole devices. The pole tower is made of steel. The surface of the tower pole steel and the inner and outer surfaces of the tower pole are hot-dipped with a modified polyethylene plastic layer. The plastic-coated steel pipe is a steel pipe coated with red modified epoxy resin powder inside and outside. It is a new type of steel pipe made on the basis of steel pipe, through sandblasting chemical pretreatment, preheating, inner and outer coating, curing, post-treatment and other processes.

It successfully solves the problems of burial, rust, scaling and other problems of plastic-coated steel pipe. There will be no pipe blocking and spray blocking, which improves the service life of fire water supply pipelines. The plastic-coated steel pipe mainly focuses on the excellent mechanical properties of steel and the excellent chemical corrosion resistance of polymer materials. The product has excellent anti-static, high-pressure and flame-retardant properties, and can withstand harsh use environments. Its super corrosion resistance greatly improves the service life of the pipeline.

This steel pipe has good pressure resistance and thermal insulation properties. It mainly protects the wires, so leakage will not occur at all. So far, plastic-coated steel pipe manufacturers are changing these advantages. The pipe wall is relatively smooth and burr-free. It is suitable for crossing cables or wires during construction.

Fire buried pipe plastic-coated steel pipe has the advantages of smooth wall thickness, good drainage performance, low fluid resistance, and no scaling, which can greatly reduce losses compared with other pipes. At the same time, the linear expansion coefficient of large-diameter plastic-coated pipes is very small, making it very advantageous as a main pipeline, greatly overcoming the defects of other plastic pipes and ordinary pipes with large linear expansion coefficients.

Plastic-coated steel pipe is an upgraded product of traditional steel-plastic pipes and galvanized pipes. It has comprehensive properties such as high strength, high elongation, good low-temperature brittleness, low expansion coefficient, corrosion resistance, wear resistance, and low fluid resistance. It belongs to a new type of water supply and drainage, anti-corrosion green large-diameter pipeline, which is more and more widely used in domestic industry.

The transmission line tower of the buried pipeline adopts plastic-coated steel pipe, which is composed of towers connected by tower pole devices. The pole tower is made of steel. The surface of the tower pole steel and the inner and outer surfaces of the tower pole are hot-dipped with modified polyethylene plastic layer. The plastic-coated steel pipe is a steel pipe coated with red modified epoxy resin powder inside and outside. It is a new type of steel pipe made of steel pipe through sandblasting chemical pretreatment, preheating, inner and outer coating, curing, post-treatment and other processes.

It successfully solves the problems of burial, rust and scaling of plastic-coated steel pipe. There will be no pipe blocking and spray blocking, which improves the service life of fire water supply pipelines. Plastic-coated steel pipes mainly focus on the excellent mechanical properties of steel and the excellent chemical corrosion resistance of polymer materials. The product has excellent anti-static, high-pressure and flame-retardant properties, and can withstand harsh use environments. Its super corrosion resistance greatly improves the service life of the pipeline.

This steel pipe has good pressure resistance and thermal insulation performance. It mainly protects the wires, so leakage will not occur at all. So far, plastic-coated steel pipe manufacturers are changing these advantages. The pipe wall is relatively smooth and burr-free. It is suitable for crossing cables or wires during construction.

Fire-fighting buried pipe plastic-coated steel pipe has the advantages of smooth wall thickness, good drainage performance, low fluid resistance, and no scaling, which can greatly reduce losses compared with other pipes. At the same time, the linear expansion coefficient of large-diameter plastic-coated pipes is very small, making it very advantageous as a main pipeline, greatly overcoming the defects of other plastic pipes and ordinary pipes with large linear expansion coefficients.

Plastic-coated steel pipe is an upgraded product of traditional steel-plastic pipes and galvanized pipes. It has comprehensive properties such as high strength, high elongation, good low-temperature brittleness, low expansion coefficient, corrosion resistance, wear resistance, and low fluid resistance. It belongs to a new type of water supply and drainage, anti-corrosion green large-diameter pipeline, which is more and more widely used in domestic industry.

3PE anti-corrosion steel pipe spraying technology, most domestic 3PE anti-corrosion steel pipe production technology adopts the production and processing technology of “epoxy powder spraying, adhesive and polyethylene lateral extrusion, winding rolling”, because the powder and electrostatic thermal spraying method does not require rolling system, thus solving the problem of thin weld coating of spiral structure welded steel pipes, saving a large amount of plastic extruders and other mechanical equipment on the production line, and reducing production energy consumption.

Specific construction: The steel pipe after shot blasting and rust removal is heated to 210°C to 220°C at a moderate temperature, and the epoxy powder is still in a molten state. The adhesive and PE are extruded into thin sheets with an extruder, sprayed and wrapped around the steel pipe, and then flattened with a roller; the epoxy powder is in powder form, and the adhesive and PE are in granular form, and only electrostatic spraying and plasticization can be used Extrusion wrap.

There are many reasons for the bending of steel pipes, such as the thermal impact of the welding seam, eccentricity during forming, compression force, imbalance of bending force, etc. But fundamentally speaking, bending is the result of internal stress in the steel pipe. Simply put, bending is stress imbalance. So, does a straight steel pipe have no internal stress? no. Straight steel pipes also have internal stress, but the internal stress of straight pipes is smaller. ​

What is internal stress? Temperature, an interaction force between molecules that causes deformation due to the influence of external forces. When steel pipes are formed and welded, they will also be affected by external forces such as welding temperature and forming bending, resulting in internal stress. The cross-section of the steel pipe is an annular shape, and two basic stresses will be generated in this annular area: a force parallel to the annular shape and a force perpendicular to the annular shape. Parallel stresses will cause the tube to become out of round; vertical stresses will cause the tube to bend. Therefore, there is a cold diameter expansion process in the production process of straight seam steel pipes. The purpose is to eliminate the internal stress of the steel pipe and increase the strength of the straight seam steel pipes. ​

The pipe that needs to be straightened is fed into the lower roller of the straightening machine from the feeding device at the left end (or right end) of the machine. The upper roller moves downward to press the pipe and stop after reaching the corresponding position. The upper and lower rollers are respectively inclined at a certain angle with the axis of the straightened pipe. The hyperbolic generatrix of the rollers matches the outer diameter of the pipe and forms an envelope shape.

The three upper rollers are pressed against the pipe under the action of their respective hydraulic cylinders, and the two lower rollers are driven to rotate by their respective hydraulic motors, driving the pipe to both rotate around the axis and move along the axial direction. Changing the rotation direction of the hydraulic motor can change the rotation direction and axial movement direction of the pipe to achieve reversible straightening. The straightened pipe is then sent to the material rack through the discharging device at the other end. For pipes with large local bending deformation, the punches at both ends can be used to perform partial straightening first, and then perform overall straightening.

I believe many people have doubts about the storage of anti-corrosion steel pipes. Let’s take a look at the storage of anti-corrosion steel pipes.

1. The appearance of anti-corrosion steel pipes entering and leaving the warehouse needs to be inspected as follows:

① Inspect each root to ensure that the surface of the polyethylene layer is flat and smooth, with no dark bubbles, pitting, wrinkles, or cracks. The overall color needs to be uniform. There should be no excessive corrosion on the surface of the pipe.

② The curvature of the steel pipe should be <0.2% of the length of the steel pipe, and its ovality should be ≤0.2% of the outer diameter of the steel pipe. The surface of the entire pipe has local unevenness <2mm.

2. The following points need to be paid attention to when transporting anti-corrosion steel pipes:

① Loading and unloading: Use a hoist that does not damage the pipe mouth and do not damage the anti-corrosion layer. All construction tools and equipment must comply with regulations during loading and unloading. Before loading, the anti-corrosion grade, material, and wall thickness of the pipes should be checked in advance, and mixed installation is not advisable.

②Transportation: A thrust baffle needs to be installed between the trailer and the cab. When transporting anti-corrosion pipes, they need to be tied firmly and measures to protect the anti-corrosion layer should be taken in a timely manner. Rubber plates or some soft materials should be installed between the anti-corrosion pipes and the frame or columns, and between the anti-corrosion pipes.

3. What are the storage standards:

① Pipes, pipe fittings, and valves need to be properly stored according to the instructions. Pay attention to inspection during storage to avoid corrosion, deformation, and aging.

② There are also materials such as glass cloth, heat-wrap tape and heat-shrinkable sleeves that need to be stored in a dry and well-ventilated warehouse.

③ Pipes, pipe fittings, valves and other materials can be classified and stored in the open air. Of course, the storage site selected must be flat and free of stones, and there must be no accumulation of water on the ground. The slope is guaranteed to be 1% to 2%, and there are drainage ditches.

④ Anti-corrosion pipes in the warehouse need to be stacked in layers, and the height needs to ensure that the pipes do not lose their shape. Stack them separately according to different specifications and materials. Soft cushions should be placed between each layer of anti-corrosion pipes, and two rows of sleepers should be laid under the lower pipes. The distance between stacked pipes should be >50mm from the ground.

⑤ If it is on-site construction, there are some storage requirements for pipes: two support pads need to be used at the bottom, the distance between them is about 4m to 8m, the anti-corrosion pipe must not be less than 100mm from the ground, the support pads and anti-corrosion Pipes and anti-corrosion pipes must be padded with flexible spacers.