Hot Dip Coating Process: This involves using a fluidized bed dipping method for plastic coating, with a one-time film formation technique. It is also known as corrosion prevention for steel-plastic composite pipes with polyethylene on both the inner and outer surfaces.
Internal and External Spray Coating Process: Based on the theory of electrostatic adsorption, a spray gun is used to apply polyethylene or epoxy resin powder onto the steel pipe after pretreatment, forming an internal and external epoxy composite steel pipe.
Curtain Coating Process: Also known as the curtain method, this process involves sprinkling powder through a sieve onto the heated outer wall of the steel pipe, resulting in an outer polyethylene and inner epoxy composite steel pipe.
Fusion Bonding and Winding Process: This process employs a hot fusion bonding and winding method, where hot melt adhesive and polyethylene are wound around a heated steel pipe to form a three-layer protective layer, namely the fusion-bonded epoxy/extruded polyethylene structural protective layer.
