SSAW Steel Pipe

The head and tail ends of steel strips are joined using single-wire or double-wire submerged arc welding to ensure continuous production, and any pipe body repair welding is also performed using automatic submerged arc welding.

3. Pre-Forming Preparation

Before forming, the steel strip undergoes leveling, edge trimming, milling, surface cleaning, conveying, and pre-bending processes to ensure stable forming quality and welding performance.

4. Hydraulic Pressure Control System

An electric contact pressure gauge is used to control the pressure of hydraulic cylinders on both sides of the conveyor system, ensuring smooth and stable strip feeding during the forming process.

5. Spiral Forming Process

The steel strip is formed into a spiral pipe using either external control or internal control roll forming systems, ensuring precise spiral angle and consistent pipe geometry.

6. Weld Gap Control

A weld gap control system is applied to precisely regulate the welding seam opening, ensuring that pipe diameter, misalignment, and weld gap meet strict welding process requirements.

7. Submerged Arc Welding (SAW)

Both internal and external welds are performed using single-wire or double-wire submerged arc welding equipment (such as Lincoln welding systems), ensuring stable arc performance, deep penetration, and high weld strength.

8. Online Ultrasonic Inspection

All weld seams are subjected to 100% online continuous ultrasonic testing (UT), and the system automatically detects defects, triggers alarms, and marks defect locations for immediate process adjustment.

9. Pipe Cutting

The continuously formed pipe is cut into individual lengths using air plasma cutting machines with high precision and clean cutting edges.

10. First Article Inspection

Each batch of pipes undergoes a strict first-piece inspection covering mechanical properties, chemical composition, fusion condition, weld surface quality, and non-destructive testing results to ensure process stability before full production release.

11. Offline Re-Inspection and Repair

Sections marked during online ultrasonic testing are re-inspected using manual ultrasonic testing and X-ray radiographic inspection; any detected defects are repaired and re-tested until full qualification is confirmed.

12. T-Joint and Weld Crossing Inspection

Strip seam welds and intersections between spiral welds and T-joints are inspected using X-ray television or radiographic film testing to ensure weld integrity at critical stress points.

13. Hydrostatic Testing

Each steel pipe is subjected to a full hydrostatic pressure test using radial sealing systems, where test pressure and duration are strictly controlled by computerized systems, with automatic recording and printing of test results.

14. End Processing

Pipe ends are machined with precise control over squareness, bevel angle, and root face dimensions to ensure accurate field welding and installation performance.


Applications
Oil and gas transmission pipelines
Water and sewage transportation
Structural and heavy-duty applications

Advantages
Cost-Effective for Large Diameter Pipes
Flexible Size Production from Steel Coils
Suitable for Long-Distance Pipeline Projects
High Production Efficiency
Good Welding Strength and Stability
Wide Range of Applications
Ideal for Piling and Structural Use