3PE anti-corrosion steel pipes should meet the standards, mainly polyethylene and high-density polyethylene, with a Vicat softening point of not less than 110; the thickness of the external anti-corrosion layer is determined according to German standards, mainly composed of low-density and medium-density polyethylene. The impact strength of 3PE anti-corrosion coating is greatly improved. The mechanical strength and weather resistance of the 3PE anti-corrosion layer are clearly specified, and the sampling frequency of the peel strength of the joint is increased. 3PE anti-corrosion pipes are usually composed of roll forming, high frequency welding, extrusion, cooling, sizing, flying saw cutting, etc. The front end of the unit is provided with a material storage looper, and the rear end of the unit is provided with a steel pipe turning frame. According to the yield effect and proximity effect, the butt weld produces a strong concentrated heat effect at the opening of the tube blank, the tube blank can be quickly heated to the temperature required for welding, and the inter-grain bonding is achieved by pressing the roller. 3PE anti-corrosion steel pipe has the characteristics of large circulation capacity and low engineering cost. The inner wall of the pipe is lubricated and there is relatively little scaling. The equivalent roughness ratio inside and outside the PE pipe is 1/20 of that of the steel pipe. Under the same diameter, length and pressure, the flow capacity of PE pipe is about 30% larger than that of steel pipe, so its economic advantage is quite high.

In the actual operation of 3PE anti-corrosion steel pipe, the three materials are mixed into one, and after treatment, they are firmly combined with the steel pipe to form an excellent anti-corrosion coating. Its processing methods are generally divided into two types: winding type and circular die coating type. Main equipment for manufacturing 3PE anti-corrosion steel pipes: steel pipe buffer platform, extubation device, traction machine, pipe threading machine, high pressure gun launcher, maintenance platform, transmission line, steel pipe preheating furnace, shot blasting machine main maintenance platform, bifurcated steel pipe return Transmission line, fast-forward roller set, fast-out roller, maintenance platform, etc. The anti-corrosion steel pipe anti-corrosion production line is suitable for the anti-corrosion operation of single-layer FBE, double-layer FBE, double-layer polyethylene, double-layer polypropylene and 3PE steel pipes. The processing pipe diameter is as small as 104 mm (4'), and the processing pipe diameter is 1600 mm (63'), and the processing capacity is more than 350 m2/h. The production line includes steel pipe conveying system, surface treatment system, pipe dust removal system, steel pipe heating system, electrostatic spraying system, painting system, water cooling system, end cutting system, hydraulic and pneumatic system, detection system and electrical control system, etc. 3pe anti-corrosion coatings combine the high impermeability and high mechanical properties of epoxy resin and polyethylene. So far, it is a globally recognized anti-corrosion coating for steel pipes, with good application effect and good performance, and has been used in many projects.