Corrosion Resistant Pipe (Petroleum Industry)
Standard
GB/T23257-2009: Specification for PE anti-corrosion layer of underground steel pipes
The corrosion resistant pipe is a buried steel pipe coated with multi layers of polyethylene. The polyethylene is an ideal material for anti-corrosion of petroleum pipelines. It can be used with epoxy paint for both external and internal coating.
Specifications:
Diameter: DN50-DN1420mm
Anti-corrosion layer: three-layer PE, two-layer PE, single-layer FBE, two-layer FBE
Technology:
3PE coating process is an advanced steel pipeline anti-corrosion technique introduced from abroad in the late 1990s. This process is used to form a great three-layer corrosion resistant layer including FBE layer, PE copolymer adhesive layer and PE layer. The FBE layer is the key anti-corrosion layer and the PE layer is used to protect the FBE layer. The two layers are bonded by adhesive.
The 3PE coating technology integrates the remarkable interface characteristic and chemical resistance of FBE layer and the great mechanical protection performance of PE layer. It provides excellent mechanical strength, and high resistance to wear, corrosion, heat and cold for oil pipelines. Therefore, 3PE coating is ideal for external protection of underground pipelines.
Main Technical Indexes of the Corrosion Resistant Pipe| Steel pipe nominal diameter DN mm | FBE coating thickness a /μm | Adhesive thickness /μm | PE coating thickness /mm | |
| Common level( G) | Reinforced level( S) | |||
| DN≤100 | ≥120 | ≥170 | 1.8 | 2.5 |
| 100 ＜ DN≤250 | 2.0 | 2.7 | ||
| 250 ＜ DN ＜ 500 | 2.2 | 2.9 | ||
| 500≤DN ＜ 800 | 2.5 | 3.2 | ||
| DN≥800 | 3.0 | 3.7 | ||
| a: not suitable for 2-layer PE coating | ||||
| Items | Properties | ||
| Two-Layer | Three-Layer | ||
| Peel strength( N/cm) | 20±10℃ | ≥70 | ≥100( cohesive failure) |
| 50±5℃ | ≥35 | ≥70( cohesive failure) | |
| Cathodic disbanding (65℃ 48h) / mm | ≤15 | ≤6 | |
| FBE curing degree/ % | -- | ≥95 | |
| Impact strength( J/mm) | ≥8 | ||
| Bending strength( -30 ℃ 2.5°) | No cracking of PE coating | ||
