(1) internal and external spraying process: using electrostatic adsorption theory, through pre-treatment of steel pipes, spray polyethylene or epoxy resin powder with a spray gun. also known as the second-generation anti-corrosion plastic-coated steel pipe, epoxy composite steel pipe inside and outside.
(2) curtain coating process: also known as the curtain method, it is coated on the outer wall of the heated steel pipe using curtain coating through a sieve filled with powder.
(3) melting and winding process: using the hot melting and winding method, hot melt adhesive and polyethylene are wound on the heated steel pipe in the form of an extruder, and react to form a three-layer structure. the full name is fusion bonded epoxy/extrusion plastic polyethylene structural protective layer.
(4) hot dipping adopts fluidized bed dipping, a one-time film-forming method. also known as the first generation of anti-corrosion plastic-coated steel pipes, polyethylene inside and outside.
(5) plastic-coated steel pipes are divided into the hot-dipping process, internal and external spraying process, rotational molding process, shower coating process, suction coating process, fusion winding process, etc.