2PE anti-corrosion and 3PE anti-corrosion

3PE anti-corrosion: The pipe features a three-layer PE anti-corrosion structure: the first layer is epoxy powder (FBE > 100um), the second layer is adhesive (AD) at 170–250um, and the third layer is polyethylene (PE) at 2.5–3.7mm. The three materials merge together and bond firmly with the steel pipe to form an excellent anti-corrosion layer. 　Pipe diameter range: Φ159～Φ1220. 2PE anti-corrosion treatment: The pipe features a two-layer PE anti-corrosion structure, with an adhesive layer (AD) as the first layer and polyethylene as the second layer; these two materials are fused together, and the thickness of each layer is the same as that in a three-layer PE structure. The difference lies in the fact that 3PE anti-corrosion treatment includes an additional epoxy powder layer. Epoxy powder offers excellent corrosion resistance, good mechanical properties, and strong resistance to cathodic disbonding. Although it requires strict surface treatment, has poor weather resistance, and a relatively high water absorption rate, it is suitable for use in buried and submarine pipelines. The thickness of its coating layer is only 0.3～0.5 millimeters, and its service life can reach 40～50 years.

Thank you. Is there any standard for PE anti-corrosion?

There is a **standard SY/T0413-2002

Currently, 3PE is used for the anti-corrosion treatment of steel pipes; the primer layer serves as an excellent transition layer. 2PE is also suitable for pipes made of other materials, such as fiberglass

SY/T0413-2002 is now expired. The latest **standard GBT 23257-2009 for polyethylene anti-corrosion coatings on buried steel pipelines should be adopted**

All the components in our unit are of 2PE type, with an anti-corrosion thickness of over 2.0 mm. The problem now is that cold winding tape is used for patching, and its performance is not satisfactory during winter construction

3PE anti-corrosion: The pipe features a three-layer PE anti-corrosion structure: the first layer is epoxy powder (FBE > 100um), the second layer is adhesive (AD) at 170–250um, and the third layer is polyethylene (PE) at 2.5–3.7mm. The three materials merge together and bond firmly with the steel pipe to form an excellent anti-corrosion layer. 　Pipe diameter range: Φ159～Φ1220. 2PE anti-corrosion treatment: The pipe features a two-layer PE anti-corrosion structure, with an adhesive layer (AD) as the first layer and polyethylene as the second layer; these two materials are fused together, and the thickness of each layer is the same as that in a three-layer PE structure. The difference lies in the fact that 3PE anti-corrosion treatment includes an additional epoxy powder layer. Epoxy powder offers excellent corrosion resistance, good mechanical properties, and strong resistance to cathodic disbonding. Although it requires strict surface treatment, has poor weather resistance, and a relatively high water absorption rate, it is suitable for use in buried and submarine pipelines. The thickness of its coating layer is only 0.3～0.5 millimeters, and its service life can reach 40～50 years. You can also refer to the **standard SY/T0413-2002 for further details**

After 10 years of collaboration between Mannesmann’s research institute and BASF Chemicals, the extruded polyolefin three-layer structure coating was introduced in the mid-1980s – namely the renowned MAPEC structure. The M A PEC structure consists of three layers of PE and three layers of PP; the three layers of PE are used for buried pipelines where the medium is transported at temperatures ranging from -20 to 70°C, while the three layers of PP are used for buried pipelines where the medium is transported at temperatures ranging from 70 to 100°C. The M A PEC structure takes advantage of the excellent properties of sintered epoxy, such as its high adhesion to steel pipes (resulting from a combination of physical and chemical bonds), as well as the advantages of polyolefins, including their good impact resistance, low water vapor permeability, and high insulation resistance. It represents a fairly effective external anti-corrosion coating for long-distance pipelines. According to a 1996 survey on pipeline coatings for natural gas pipelines published in the American \"Pipeline Digest\", three-layer polyolefin coatings ranked second in terms of usage

At present, polyethylene, adhesives, and epoxy powders are all produced domestically. Taking the ordinary-grade anti-corrosion coating for § 660 pipes as an example, the prefabrication cost has dropped from 106–108 yuan per öm2 to below 90 yuan per öm2, creating favorable conditions for the widespread use of such coatings in the West-East Gas Transmission project