The most common materials to coat pipes externally are:
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)
The main types of non metallic pipe coating materials, and their advantages/disadvantages, are summarized in the table below:
Pipe Coating Type
Three-layer Polyethylene (3LPE) and 3 layers Polypropylene (3LPP)
Low material and application cost
Recommended for deep sea applications with relatively high temperature and pressures
for deep sea
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
Asphalt enameled and polyurethane (PUR)
Cheap and superior to coal enamelReduces the hysteresis
Hunan Gaoxing Steel Development Zone, No.1888 Purui South Rd, Wangcheng District,Changsha, Hunan, China