2PP/3PP anti-corrosion steel pipe

Update time：2025-03-31

I. 2PP/3PP anticorrosion steel pipe definition:

i.2PP anticorrosive steel pipe

Structural composition: it consists of two layers of structure, the first layer is adhesive (AD) with a thickness of 250-400μm; the second layer is polypropylene (PP) with a thickness of 1.4-4.0mm.

Characteristics: This structure is relatively simple, but still can provide good anti-corrosion performance, suitable for some relatively low requirements for anti-corrosion occasions.

ii. 3PP anti-corrosion steel pipe

Structural composition: composed of three-layer structure, the first layer is epoxy powder (FBE), with a thickness of 50-100μm; the second layer is adhesive (AD), with a thickness of 250-400μm; the third layer is polypropylene (PP), with a thickness of 1.4-4.0mm.

Characteristics: The three-layer structure provides better anticorrosion performance and mechanical protection performance, which can effectively resist corrosion and mechanical damage from the external environment, and is suitable for pipelines conveying higher temperature media and desert areas with higher surface temperature and longer sunshine time.

II. Performance characteristics of 2PP and 3PP anti-corrosion steel pipe

i. 2PP anti-corrosion steel pipe

Anti-corrosion performance: it has good chemical stability and can effectively prevent corrosion of soil, water and microorganisms.

Mechanical properties: the polypropylene layer is thicker and has a certain degree of impact resistance and abrasion resistance.

Construction performance: the coating is thin, the construction is relatively simple, but the ambient temperature requirements are high.

ii. 3PP anti-corrosion steel pipe

Anti-corrosion performance: three-layer structure enhances the anti-corrosion effect, epoxy powder bottom layer provides good adhesion, polypropylene outer layer provides excellent chemical resistance and weather resistance.

Mechanical properties: strong impact resistance, wear resistance, can effectively resist mechanical damage.

Construction performance: the construction process is more complicated, but the coating performance is more stable and adaptable.

III. Application Fields

i. 2PP anti-corrosion steel pipe

Application fields: 2PP anticorrosive steel pipe is mainly used for anticorrosive protection of general industrial pipelines, and is suitable for water transmission, gas transmission and other media transportation.

Environmental adaptability: due to its relatively simple structure, it is more suitable for use in areas with lower ambient temperature and weaker corrosivity.

ii. 3PP anti-corrosion steel pipe

Application areas: 3PP anticorrosive steel pipe is widely used in oil, natural gas, heating, water supply and other industries, especially suitable for pipelines conveying higher temperature media.

Special environment: in desert areas with high surface temperature and long sunshine time, 3PP anticorrosion steel pipe is widely used in buried water, gas and oil pipelines because of its excellent heat resistance and weather resistance.

IV. Manufacturing process of 2PP and 3PP anti-corrosion steel pipe

i. 2PP anti-corrosion steel pipe manufacturing process

Pre-treatment: sandblasting and descaling the steel pipe to remove the surface rust, oxidized skin and impurities, and reach the specified descaling grade.

Coating adhesive: use electrostatic spraying or extrusion winding to coat the surface of the steel pipe with a layer of adhesive (AD), with a thickness of about 250-400 μm.

Coating polypropylene layer: A polypropylene (PP) layer is coated on top of the adhesive layer, with a thickness of 1.4-4.0mm, usually by extrusion winding process.

Curing: Curing by natural cooling or heating, so that the coating is firmly attached to the surface of the steel pipe.

Inspection and packaging: quality inspection of the finished product, packaging after passing.

ii. 3PP anti-corrosion steel pipe manufacturing process

Pre-treatment: Same as 2PP, the steel pipe should be treated with sand blasting and rust removal to ensure the surface is clean.

Coating epoxy powder: using electrostatic spraying process, the surface of the steel pipe is evenly coated with a layer of epoxy powder (FBE), the thickness of about 50-100μm.

Adhesive coating: Coat the epoxy powder layer with a layer of adhesive (AD) with a thickness of about 250-400μm.

Polypropylene coating: A polypropylene (PP) layer is coated on top of the adhesive layer, with a thickness of 1.4-4.0mm, usually by extrusion winding process.

Curing and Cooling: Curing by natural cooling or heating, so that the coating is firmly attached to the surface of the steel pipe.

Inspection and packaging: quality inspection of the finished product to ensure that the coating thickness, adhesion and other indicators meet the requirements for packaging.

V. Execution standard of 2PP and 3PP anti-corrosion steel pipe

i. China

2PP anticorrosive steel pipe: China has not yet formulated a special industry standard for 2PP anticorrosive steel pipe.

3PP anticorrosive steel pipe: China has not yet formulated the industry standard for 3PP coating, and usually adopts the German DIN30678 "Polypropylene Coating for Steel Pipes" standard.

ii. International Standards

ISO 21809-1:2011: It specifies the technical requirements for three-layer polyethylene (3LPE) and three-layer polypropylene (3LPP) anti-corrosion coatings for welded steel pipes and seamless steel pipes used in pipeline transportation systems in the oil and gas industry.

ISO 12944: This is an international standard on corrosion protection of protective coating systems for steel structures. Although it is not a standard specifically for anti-corrosion steel pipes, the classification of corrosive environments and the recommendation of coating systems in it are also of some reference value for the design and application of anti-corrosion steel pipes.

iii. Germany

DIN30678: This is the German standard for polypropylene coatings for steel pipelines, which is widely used in the production and acceptance of 3PP anti-corrosion steel pipes.