Online Exporter Tianjin Youfa Brand Spiral Welded Steel Pipe

Spiral Welded Steel Pipes Manufacturing Process

Material Selection:

Steel Coils: High-quality steel coils are selected, typically made from low-carbon or medium-carbon steel, to meet required mechanical properties and chemical composition.

Uncoiling and Slitting:

Uncoiling: The steel coils are uncoiled and flattened into a sheet form.
Slitting: The flattened steel is slit into strips of the required width. The width of the strip determines the diameter of the final pipe.

Forming:

Spiral Formation: The steel strip is fed through a series of rollers that gradually form it into a spiral shape. The edges of the strip are brought together in a helical pattern to form a pipe.

Welding:

Submerged Arc Welding (SAW): The spiral seam of the pipe is welded using the submerged arc welding process. This involves the use of an electric arc and a granular flux, which provides a strong, high-quality weld with minimal spatter.
Weld Seam Inspection: The weld seam is inspected for quality using non-destructive testing methods such as ultrasonic or radiographic testing.

Sizing and Shaping:

Sizing Mills: The welded pipe passes through sizing mills to achieve the precise diameter and roundness required.
Expansion: Hydraulic or mechanical expansion may be used to ensure uniform pipe dimensions and to enhance material properties.

Non-Destructive Testing:

Ultrasonic Testing (UT): Used to detect internal defects in the weld seam.
Hydrostatic Testing: Each pipe is subjected to hydrostatic pressure testing to ensure it can handle the operating pressures without leaking.

Finishing:

Beveling: The ends of the pipes are beveled to prepare for welding at the installation site.
Surface Treatment: Pipes may receive surface treatments such as cleaning, coating, or galvanizing to enhance corrosion resistance.

Inspection and Quality Control:

Dimensional Inspection: The pipes are checked for compliance with diameter, wall thickness, and length specifications.
Mechanical Testing: Pipes are tested for tensile strength, yield strength, elongation, and toughness to ensure they meet required standards.

Marking and Packaging:

Marking: Pipes are marked with important information such as the manufacturer’s name, pipe specifications, grade, size, and heat number for traceability.
Packaging: Pipes are bundled and packaged according to customer requirements, ready for transportation and installation.