1. Steel Pipe Inspection: Sort out any base pipes with quality issues to prevent them from entering the next production step and reduce raw material waste.
2. External/Internal Sandblasting: Sandblasting removes dirt, oxide scales, welding slag, and other impurities from the inner wall of the steel pipe. It smoothens the inner surface of the steel pipe and reduces internal surface stress. This effectively enhances the service life of the steel pipe, reduces internal corrosion, and improves both the internal and external quality of the steel pipe.
3. Internal Blowing: Blow out the steel grit and dust inside the steel pipe to avoid affecting internal spray coating.
4. Medium Frequency Heating (Internal Spraying): Heat the steel pipe to a certain temperature while removing moisture to prepare for internal spray coating.
5. Internal Spray Coating: With the help of pressure, the coating material is dispersed into uniform and fine droplets and applied to the inner surface of the steel pipe to achieve a uniform coating layer.
6. Medium Frequency Heating (External Spraying): Heat the steel pipe to a certain temperature while removing moisture to prepare for external spray coating.
7. External Spray Coating: With the help of pressure, the coating material is dispersed into uniform and fine droplets and applied to the outer surface of the steel pipe to achieve a uniform coating layer.
8. Extrusion Wrapping: Plastic particles are fully mixed, melted, and heated through a screw extruder. The molten material is extruded from a slot-shaped die and then wrapped and coated onto the surface of the steel pipe through a rotating roller. At the same time, the steel pipe advances in a spiral manner, driving the extrusion of the plastic film, thereby achieving continuous production.
9. Spray Cooling: The purpose of cooling is to fully solidify the polyethylene layer and improve its mechanical properties.
10. Pipe End Treatment: According to welding process requirements, a reserved length of 100 to 150mm is left at the ends of the corrosion-resistant pipes for pipe end treatment and connection.
11. Electric Spark Testing: Inspecting for leakage points in the corrosion protection layer can reduce the outflow of defective products and improve product quality.
12. Inkjet Coding: Coding is done according to national requirements.
13. Packaging: Makes product information visible and traceable.
