Polyethylene, due to its favorable mechanical and chemical properties for several decades is used in corrosion protection of buried and submerged pipelines for transporting gas, oil or water. To be resistant to the heat and UV it is stabilized with antioxidants.
Polyethylene coating is designed for operating temperatures up to 50˚C by using low density polyethylene (LDPE), and up to 70˚C for medium-density polyethylene (MDPE) and high-density polyethylene (HDPE). With increasing the density it is improved mechanical properties of polyethylene.
Preparing the surface of the tube is performed by grit/shot blasting to ensure Sa 2½ degree of cleanliness (with a steel shot and steel grit).
Coating consist of two layers:, namely:
- Layer of electrostatic powdering adhesive applied to heated pipe about 180˚C
- Layer of polyethylene applied with the sleeve extrusion process.
Outside diameter of pipe (D): from 88.9 mm to 813mm
Standard for coating application: DIN 30670, HF49704, EN10288
Types of coatings:
- N-n, N-v, S-n, and S-v (DIN 30670);
- class 1, class 2 and class 3 (N F 49 704)
100% porosity test – test voltage 25KV
Cut back: 130mm to 150mm
Protective caps or steel rings – at the request of the customer
Pipe length: 6 m to 12.2 m
Each pipe has written text that contains a trademark and company name, size and quality of materials, the standard by which the pipe is made and the type and standard of making the external coating. When pipes are packaged in bundles (diameter less than 219mm), marking text is on the label fixed to each package.
