2PP/3PP anti-corrosion steel pipe

Published:2025-03-31 | Last Updated: 2025-06-13    Views: 36

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 Corrosion-Resistant Steel Pipe Manufacturing Process

Pre-treatment: The SSAW Steel Pipes undergo sandblasting and rust removal to eliminate surface rust, scale, and impurities, achieving the specified rust removal grade.

Adhesive Coating: Using electrostatic spraying or extrusion winding technology, a layer of adhesive (AD) is applied to the steel pipe surface, with a thickness of approximately 250–400 microns.

Polypropylene (PP) Layer Coating: A polypropylene (PP) layer is applied over the adhesive layer, with a thickness of 1.4–4.0 mm, typically using an extrusion winding process.  

Curing: The coating is cured through natural cooling or heating to ensure it adheres firmly to the steel pipe surface.  

Inspection and Packaging: The finished product undergoes quality inspection, and upon passing, it is packaged.  

ii. 3PP Corrosion-Resistant Steel Pipe Manufacturing Process

Pre-treatment: Similar to 2PP carbon steel welded pipes undergo sandblasting rust removal to ensure a clean surface.  

Epoxy powder coating: Using an electrostatic spraying process, an epoxy powder (FBE) layer is uniformly applied to the steel pipe surface, with a thickness of approximately 50–100 μm.

Adhesive Coating: An adhesive layer (AD) is applied over the epoxy powder layer, with a thickness of approximately 250-400 μm.  

Polypropylene Coating: A polypropylene (PP) layer is applied over the adhesive layer, with a thickness of 1.4-4.0 mm, typically using an extrusion winding process.

Curing and cooling: Curing is performed through natural cooling or heating to ensure the coating adheres firmly to the steel pipe surface.  

Inspection and packaging: The finished 3PE reinforced anti-corrosion steel pipes undergo quality inspection to ensure coating thickness, adhesion, and other indicators meet packaging requirements.

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.

VI. Common spiral steel pipe specifications table