Three Layers Polyethylene External Coating for Steel Pipes and Fittings

Why external 3PE coating?

In long distance conveyance of crude oil, natural gas or refined oil, the pipeline usually need to be buried underground. When steel pipes or pipe fittings are in contact with soil and waters, we must consider its external anti-corrosion performance to ensure a durable lifespan of the pipeline. The three layers polyethylene(3PE/3LPE) external coating perfectly solves this problem. It consists of a high performance fusion bonded epoxy(FBE) layer, an adhesive layer and an outer layer of high density polyethylene. The three layers external coating has excellent resistance to abrasion, wear, acid, alkali and cathodic disbonding, etc.

The production process of three layers polyethylene external coating

Unless otherwise specified by the purchaser, the 3PE(also called 3LPE) coating will be produced and inspected as per EN DIN 30670: Polyethylene coatings for steel pipes and fittings.

Three Layers Polyethylene External Coating Flow Chart

As illustrated in the flow chart above,

1)All bare pipes or fittings should be preheated first then clean the external surface by sand-blasting and grinding.

2) After surface inspection, qualified pipes will be conveyed to the facility to take final surface treatment to remove even tiny dust from the pipe external surface.

3) Mid-frequency induction heating.

4) Fusion Bonded Epoxy coating.

5) Extrude or spray copolymer adhesive.

6) Extrude the polyethylene layer. Make sure it's wounded onto the adhesive layer correctly.

7) Quenching by circulating cold water.

8) Standard inspection as per EN DIN 30670.

9) Packaged and stocked.

Views: Author：hbmetals Date:15/02/06