3PE coating Pipe has three layer PE antisepsis structure: the first layer with epoxy powder (FBE> 100um), the second layer with adhesive (AD), 170 – 250um, the third layer with polyethylene (PE) 2.5 – 3.7mm.

Diameter range 60mm-1420mm, wall thickness 2.5-18mm, which is a good anti-corrosion method, generally can improve the service life of 50 years, not only extended the replacement cycle of the underground plumbing, and significant cost savings for the provides a strong role in nation-building.

3PE anti-corrosion is the most commonly used method of anti-corrosion, in addition to 2PE, 2PP, 3PP, their manufacturing process is similar to but different raw materials, this anti-corrosion characteristics of the simple fabrication process, the preservative effect, inexpensive pipe manufacturing industry generally agree that corrosion.

3PE, we also called 3LPE. 3PE coated steel pipe is one kind of coating method which used in carbon steel pipe. No matter it is a seamless steel pipe of welded steel pipe, stainless steel pipe or alloy steel pipe, nickel alloy pipes or CRA clad or lined pipe, it can do 3PE coating for the pipes.

3PE coating is the most commonly used method of anti-corrosion, in addition to 2PE, 2PP, 3PP. The manufacturing process of these coating are similar, but raw materials are different. This 3LPE manufacturing process is very simple. And it has good corrosion resistance and excellent anti-corrosion effect.

ADVANTAGES OF THE THREE-LAYER COATING SYSTEM

Excellent corrosion resistance.
When exposed to either acid or alkaline media, an extended lifetime in highly corrosive soils is assured.
Strong steel adhesion: 20 times more adhesive than traditional plastic tape systems.
Excellent cathodic disbondment test results.
Excellent mechanical resistance.

High dielectric resistance : Superior bending ability for pipe laying applications

High impermeability: Both the high-density polyethylene and polypropylene have low water permeation characteristics that allow improved isolation from the surrounding sea water compared to other coating systems

3PE anticorrosive steel pipe characteristics:

very high tightness,which can greatly save energy, reduce costs, protect the environment in long-term operation.
strong corrosion resistance, the construction side simply speed, the service life can be up to 30-50 years.
with good resistance to corrosion and impact resistance, low water absorption, the PE (less than 0.01%) at low temperatures.
high strength epoxy, PE absorbent and hot melt adhesive softness, etc., have high corrosion reliability.

3PE anti-corrosion insulation steel pipe construction attention

3PE anti-corrosion insulation steel pipe because the closed cell rate of polyurethane foam can reach more than 92%, therefore, the use of polyurethane foam as the insulation layer of the direct buried pipeline, can not only play the role of thermal insulation, but also can effectively prevent water, moisture and other corrosive liquids, gas infiltration, to prevent the growth and development of microorganisms. Strong adaptability: Polyurethane foam does not have a strong bond with various materials, so as a direct buried pipe, the insulation layer hardly needs to be considered for the anti-corruption layer to adhere to it.

3PE anti-corrosion insulation steel pipe hard foam raw materials and proportions should be suitable for pouring construction, and the expansion force generated by polyurethane foam on the template after pouring construction should be as small as possible; In order to resist the large bulging force that may be generated by polyurethane foaming on the formwork during pouring construction, stiffeners can be installed outside the formwork to ensure the specifications of the outer layer after demolding. The mold can be removed after 30~40 minutes after the end of pouring. The polyurethane rigid foam insulation layer after pouring should be fully standing for 24 hours, and then carry out the construction of the next process, the outer scaffolding should be checked before the use of the scaffolding board whether there are voids, probe plates, protective rails, foot stops, confirmed qualified, can be used, during the operation of the scaffolding and the building between the pull, without the consent of the leader, it is strictly forbidden to dismantle.

3PE anti-corrosion insulation steel pipe if necessary by the rack worker responsible for taking reinforcement measures, can be removed, the tools and materials on the scaffolding should be scattered and stable, shall not exceed the allowable load, it is strictly forbidden to step on the protective railing of the scaffolding and balcony railings to operate, the use of hand-held power tools, must be equipped with leakage protector, before the operation of the test machine inspection, the operation should wear insulating gloves, quality control. Polyurethane storage and construction operation area should focus on fire prevention measures, the site is equipped with fire extinguishers, there should be no open flame within 20 meters of the perimeter, in case of strong wind and heavy rain above grade, outdoor high work should be stopped.

Material analysis of 3PE anti-corrosive steel pipe

3PE anticorrosive steel pipe base material includes seamless steel pipe, spiral steel pipe and straight seam steel pipe. The three-layer structure polyethylene (3PE) anticorrosive coating has been widely used in the petroleum pipeline industry due to its good corrosion resistance, water vapor permeability resistance, and mechanical properties.

Introduction to the anti-corrosion layer of 3PE anti-corrosion steel pipe

3PE anti-corrosion steel pipe-an anti-corrosion layer is crucial to the life of buried pipelines. Some pipes of the same material are buried in the ground for decades without corrosion, and some leak in several years. It is because they use different outer coatings.

3PE anti-corrosion generally consists of 3 layers of structure:

First layer of epoxy powder (FBE> 100um)
Second layer of adhesive (AD) 170 ～ 250um
The third layer of polyethylene (PE) 2.5 ～ 3.7mm

In the actual operation, the three materials are mixed into a whole, and after processing, it is firmly combined with the steel pipe to form an excellent anticorrosive layer. Its processing methods are generally divided into two types: winding type and round mold coating type.

Advantages of 3PE anti-corrosive steel pipe anti-corrosive layer

The coating of 3PE anti-corrosion steel pipe is an epoxy powder anti-corrosion coating which is in contact with the bottom layer and the surface of the steel pipe. The middle layer is a copolymerized adhesive with branch structure functional groups. The top layer is a high-density polyethylene anticorrosive coating. 3PE anti-corrosion steel pipe coating (three-layer polyethylene anti-corrosion coating) is a new type of anti-corrosion produced by skillfully combining 2PE anti-corrosion coating in Europe and epoxy powder anti-corrosion steel pipe coating (FBE) widely used in North America Steel tube coating. It has been recognized and used worldwide for more than a decade.

3PE anti-corrosion steel pipe inspection process

First, inspect the anti-corrosion steel pipe, and comprehensively inspect the steel pipe to meet the conditions for making insulated steel pipes. Check the steel pipe for corrosion, check and remove the embroidery on the steel pipe. The next step is to put the steel pipe after derusting and anticorrosion in a polyethylene casing to form a pipe. However, after the head is repaired, polyurethane foam is injected into it, and the gap must be fully filled to make it fully filled. Inspection of anti-corrosion steel pipes, and inspection of finished products of finished insulated steel pipes.

Before the 3PE anti-corrosive steel pipe base material is subjected to anticorrosive treatment, it is necessary to inspect and record the steel pipe entering the pipe entry platform, perform shot blasting and rust removal on the outer surface of the steel pipe, and then check whether the cleanliness of the outer surface of the steel pipe and the depth of the anchor pattern meet the requirements. Non-compliant grinding with hand wheel qualified, winding tape on the tube end, dust treatment, intermediate frequency heating to the required temperature, epoxy powder spraying, winding on the adhesive extruder side, entanglement on the PE extruder side, anti-corrosion The pipes are water-cooled, the qualified products are spray-labeled, and the lower pipe platforms and stacks are ready for shipment.

3PE anti-corrosion steel pipe use

Anti-corrosion steel pipe base material includes spiral pipe, straight seam pipe, seamless pipe, etc., which are widely used in long-distance water transmission, petroleum, chemical industry, natural gas, heat, sewage treatment, water sources, bridges, steel structures, marine water transmission piling and other pipeline engineering fields in China.

3PE anti-corrosion steel pipe cutting treatment problem

After the 3PE anti-corrosion steel pipe is straightened, the initial inspection and sootblowing should be carried out to determine the length of the cutting head and tail. The purpose of 3PE anti-corrosion steel pipe cutting is to remove the end with cracks, knots, scars, tears and uneven wall thickness, so as to obtain the required fixed length 3PE anti-corrosion steel pipe, and also remove defects that are difficult to save after inspection, such as inner folding, inner scarring, serious uneven wall thickness, etc. Generally, the former cut-off is carried out on the work line, while the latter is cut off offline

Control of heat preservation time of 3PE anti-corrosion steel pipe during heat treatment

The heat preservation time of 3PE anti-corrosion steel pipe should ensure that the steel pipe in the furnace can be completely burned through, so that its temperature is uniform, and the due tissue transformation is completed, so as to obtain uniform structure and performance. Generally, increasing the heating temperature can appropriately shorten the holding time. When performing low-temperature annealing (including softening, stress relief and recrystallization annealing), the closer the annealing temperature is to the lower critical point A1, the faster the recovery of the 3pe anti-corrosion steel pipe, the more complete the effect of eliminating work hardening, therefore, the holding time can also be appropriately shortened.

What is 3PE coating pipe?

3PE coating tube is short for “three layers anti-corrosion polyethylene structure steel tube coating”. There are three layers in this pipe coating structure:

The first: Epoxy layer (Thickness > 100um)
The second: Adhesive layer (Thickness: 170um-250um)
The third: Polyethylene layer (Thickness: 1.8 x 3.7 mm).

What is the characteristic of 3PE coating pipe

3PE coated pipe is the most advanced technology for pipe anti-corrosion. It brings together the advantage of 2PE coating pipe and FBE coating pipe, while avoiding their weaknesses. Each layer of the 3PE coated pipe has its unique function in the coating structure.

The epoxy layer is for the main function of anti-corrosion. It has a strong connection with the bare steel pipe surface, favorable cathodic debono property, wide temperature range (-40 oC-100 oC) and low water absorption quality.

The adhesive layer is to connect the epoxy layer and the PE layer, the main chemical composition of which is polyolefin. The polar functional group of polyolefin can generate a hydrogen bond or chemical bond with the epoxy group of the FBE layer, making a firm connection with the lower layer. At the same time, the nonpolar ethylene of polyolefin has affinity interaction with the PE layer, also generating a favorable adhesive property with the front layer.

PE layer has favorable electrical insulation property, low water absorption quality and strong resistance to mechanical damage. This layer mainly has mechanical protection and anti-corrosion function.

So 3PE coated tube is a kind of system composed of these three layers with different functions, so the whole system is full-featured to better protect the pipe.

What is the advantage of 3PE coating steel pipes

The normal bare pipe will corrode in the harsh environment and its service life will be reduced, making the construction and maintenance cost very high. But because each layer of the 3PE coating system has its good performance, the 3PE coated pipe can protect the pipe in the harsh environment and extend its service life to 30-50 years even more. It can significantly reduce the cost of construction and maintenance of the pipeline. At the same time, 3PE coated pipe has a favorable thermal insulation property, the thermal losses is only 25% of the traditional pipe, saving a lot of energy cost during operation. At last, 3PE coated pipe can be placed directly underground or in water, even directly in frozen earth due to its good anti-corrosion property and low temperature impact resistance property, no need to build trench.

What is the Use?

Due to the characteristic and advantage of 3PE coated pipe, it is widely used in many kinds of applications such as oil and gas, water transmission, heat transmission, mining, fire fighting, thermal power station, electric power, communication facilities, road, pharmaceutical chemical, printing and dyeing and agricultural applications. And with its further development, 3PE coated pipe will play an increasingly important role in global development.