The domestic execution standard for 3PE anticorrosive steel pipes is SY/T0413-2002, which was implemented on August 1, 2002. This standard primarily regulates the use of polyethylene and high-density polyethylene, with a Vicat softening point set at no less than 110°C. The thickness of the external anticorrosive layer is determined according to the German standard DIN30670-1991, which focuses on low- and medium-density polyethylene, significantly enhancing the impact strength of the 3PE anticorrosive layer. SY/T0413-2002 significantly raises the peel strength and impact resistance indicators of the 3PE anticorrosive layer, and clearly specifies the carbon black content of some special materials, ensuring the mechanical strength and weather resistance of the 3PE anticorrosive layer. Additionally, it increases the frequency of spot checks for the peel strength of the joint coating (i.e., the peel strength of the heat shrinkable sleeve and tape to the primer-coated steel).
Anticorrosive Structure for Steel Pipe Outer Wall
The 3PE anticorrosion system generally comprises three layers:
1st Layer: Epoxy Powder (FBE > 100um)
2nd Layer: Adhesive (AD) 170~250um
3rd Layer: Polyethylene (PE) 1.8~3.7mm
In practical operations, these three materials are blended and integrated, processed to form a strong bond with the steel pipe, creating an excellent anticorrosive layer. The processing methods generally include winding and circular die coating.
The 3PE anticorrosive coating for steel pipes, also known as the three-layer polyethylene anticorrosive coating, is a new type of coating that ingeniously combines the 2PE anticorrosive coating from Europe with the widely used epoxy powder anticorrosive coating (FBE) for steel pipes in North America. This coating has been recognized and used worldwide for over a decade.
The coating of 3PE anticorrosive steel pipes consists of an epoxy powder anticorrosive coating in contact with the steel pipe surface as the bottom layer, a copolymer adhesive with functional groups and a branched structure as the middle layer, and a high-density polyethylene anticorrosive coating as the top layer.
The 3PE anticorrosive coating integrates the high impermeability and excellent mechanical properties of both epoxy resin and polyethylene materials. It is globally recognized as the most effective and high-performance anticorrosive coating for pipelines, thus widely applied in numerous engineering projects.
