COATED PIPES
Pipes may be coated externally to be protected from corrosion, erosion and possible mechanical stress. Pipe coating consists of the application of metallic, or non-metallic, materials on the external surface of the pipe (either seamless or welded). External pipe coatings are used to protect the metal from corrosive environments (3LPE coated pipes are the most common choice).
Most Common Coat Pipes Externally Materials:
Non-metallic pipe coating: Paints, varnishes, lacquers, bituminous coatings, resins, plasticizers, Greases, waxes, oils, Plastics (polyurethane, polyethylene, Rilsan, PTFE, PVC), Elastomers (various types), Vitreous enamel, Cement mortar
Organometallic pipe coating: Paints pigmented with metals in powder form (aluminum, zinc, lead, stainless steel), Paints containing zinc ethyl-silicate
Chemical modification: Phosphating, Chromatin, phosphating, Black finishing, and browning
Cementation (physiochemical modification)
3LPE COATED PIPES
3LPE coated pipes feature a three-layer polyethylene coating consisting of:
a high-performance fusion bonded epoxy (FBE),
a copolymer adhesive
an outer layer of polyethylene which provides tough, durable protection against corrosion and erosion.
3LPE pipe suit medium to high operating temperatures.
Pipe Coating Materials and Advantages/disadvantages:
| Pipe Coating Type | Advantages | Disadvantages |
| Three-layer Polyethylene (3LPE) and 3 layers Polypropylene (3LPP) | Low material and application cost |
Application of flame in pipeline environments has traditionally been the cause of workplace fires and explosions Requires application of flame to create adhesion Limited heat resistance. Maximum 225°F to 250°F. Limited dimensional stability Features just a borderline hardness Shows poor resistance to sulfur, amines, oxygen, and other oxidants. |
| Polypropylene (PUR) | Recommended for deep sea applications with relatively high temperature and pressures | Polypropylene is liable to chain degradation from exposure to heat and UV radiation such as that present in sunlight. |
| Fusion Bonded Epoxy (FBE) | Excellent chemical resistance and great dimensional stability with minimized hysteresis |
Rather expensive application cost per meter FBE materials are expensive The pipe and the coating materials must be heated to approx 250°F Long lead times |
| Asphalt enameled and polyurethane (PUR) | Cheap and superior to coal enamelReduces the hysteresis Fast treatment |
Modest resistance to chemical aggression Strict temperature ranges Limited dimensional stability |
HT PIPE is a supplier of carbon steel, stainless steel, and nickel alloy materials. If you have any needs about carbon steel, nickel alloy, stainless steel pipes, steel plates, round bars, pipe fittings, and flanges, contact us for free information!
