Production Process of Spiral Steel Pipe

Spiral steel pipe is a common form of welded steel pipe widely used in water supply, oil and gas transmission, municipal engineering, and structural engineering. Spiral steel pipe refers to a type of steel pipe made by continuously forming and welding steel coils into a spiral shape, which can produce large-diameter pipes from narrow-width steel strips. The forming and welding quality of spiral steel pipe is very important for the service life and safety of the pipeline, which is crucial when we choose the supplier.

The production process of spiral steel pipe includes several key stages: raw material preparation, forming, welding, sizing, and inspection. Each step is precisely controlled to ensure the dimensional accuracy, mechanical performance, and anti-corrosion potential of the finished pipe.

1.Raw Material Preparation

The first and most basic step is the preparation of steel coil. High-quality hot-rolled steel coils are selected according to the required specifications, grade, and wall thickness. The coil is then uncoiled, leveled, and cleaned to remove surface contaminants, rust, and oil. Edge trimming and beveling are also performed to ensure the edges are straight and ready for welding.

2.Continuous Forming

The prepared steel strip is fed into the forming machine at a controlled angle. The strip is continuously bent into a spiral shape by a series of forming rollers. The forming angle is precisely adjusted according to the required pipe diameter, which allows the production of various diameters from the same width of steel strip. This process ensures the pipe has a uniform roundness and wall thickness.

3.Submerged Arc Welding

The formed pipe seam is then welded using the submerged arc welding (SAW) process. This is typically done with both an internal weld and an external weld. The welding parameters, including current, voltage, and travel speed, are strictly controlled to ensure a full penetration, defect-free weld. The use of flux protects the weld pool, resulting in a strong, high-quality weld with excellent mechanical properties.

4.Sizing and Straightening

After welding, the pipe is passed through a sizing and straightening machine. This process corrects any minor deviations in roundness and straightness caused by the forming and welding processes, ensuring the pipe meets the required dimensional tolerances. The pipe is then cut to the specified length using a flying cut-off machine.

5.Finishing and Quality Inspection

The cut pipe ends are deburred and prepared for inspection. Every finished spiral steel pipe undergoes comprehensive quality control before delivery:

Only pipes that pass all inspections are marked with specifications, batch numbers, and certification marks, then packaged for delivery. With mature production technology and strict quality control, spiral steel pipe provides a reliable, cost-effective solution for large-diameter pipeline projects worldwide.