Briefly introduce the manufacturing process of plastic-coated spiral steel pipes with flange connections.

The processing technology of large-diameter epoxy coal tar anticorrosive steel pipes is divided into four methods: hot-dip galvanizing, high-pressure static spraying, rotational molding, and sheath molding. The process varies depending on the type of connection used. The raw materials required for this product are plastic powder and steel pipes. The entire production process begins with the procurement of raw materials, where the commonly used plastic powder for fire protection is epoxy resin. The steel pipes used are typically seamless, straight seam, or spiral pipes. After the raw materials are purchased, they undergo inspection, particularly for steel pipes and other organic materials that make up the steel-plastic composite pipes. These pipes not only possess the high strength, ease of connection, and resistance to water flow impact of steel pipes but also overcome the drawbacks of steel pipes, such as susceptibility to corrosion, pollution, scaling, and the low strength and poor fire performance of plastic pipes. The main drawback is that the pipes cannot be bent during installation. When performing operations like thermal processing and electric welding cutting, the cutting surfaces should be coated with the ambient temperature curing adhesive provided by the manufacturer.