Fusion-bonded epoxy coated steel pipes, also known as coated steel pipes, steel-plastic composite pipes, and coated steel-plastic composite pipes, are steel pipes with a plastic anti-corrosion layer fused onto their inner surface or both inner and outer surfaces through spray, roll, dip, or vacuum coating processes. The main inspection methods for coated steel pipes include visual inspection, pinhole testing, bending tests, flattening tests, and low-temperature tests, each with its own focus. Coated steel pipes are based on welded or seamless steel pipes, with the inner and outer walls coated with epoxy resin or polyethylene powder, making them anti-corrosive, erosion-resistant, non-toxic, and radiation-free green environmental protection pipes, suitable for various fluid conveyances.

Steel pipes with longitudinal seam welding should comply with the requirements of GB/T3091-2008 for steel pipes. Seamless steel pipes should meet the requirements of GB/T8163-2008 for steel pipes. Spiral seam submerged arc welded steel pipes should adhere to the specifications of SY/T5037-2000 for steel pipes. The coated steel pipes retain the stiffness and strength of traditional metal pipes, far superior to plastic and aluminum-plastic pipes. They offer non-scaling friction resistance, lightweight, good flexibility, impact resistance, and high pressure-bearing strength. They are suitable for a wider temperature range of -30℃ to 100℃. The steel strips in the perforated steel pipe are pierced with many holes, allowing the inner and outer layers of PE to integrate into a single unit, thereby solving the compatibility issue between steel and plastic. However, this sacrifices the oxygen-blocking performance of the steel-plastic pipes. Moreover, the presence of the perforated steel strip significantly reduces the pressure-bearing strength of this type of steel-plastic pipe, leading to potential localized pipe bursting under high-pressure conditions.