SSAW Pipes offer cost-effective, large-diameter solutions compared to LSAW and ERW pipes, ideal for water, piling, and low-pressure applications. Below is a comparison of key features.

Spiral Submerged-arc Welded steel pipe technological process

Spiral welded pipe production by submerged arc method is based on using tandem welding technique for joining inside and outside coil edges, which have been trimmed and beveled by carbide milling for high quality weld structure.

Thermatool designs and manufactures Spiral Seam Annealing systems for producers of SAW (submerged arc welded) API line pipe.

Offering all the basic features and benefits of Thermatool seam annealing systems designed for operation on longitudinally welded API pipe, Thermatool Spiral Seam Annealing systems, however, require the installation of specially “shaped” inductors.

These are custom designed on CAD systems in order to precisely follow the helix angle for a specific pipe diameter.

The manufacturing process of the spiral steel tube (SSAW):

1. The raw materials are strip coil, welding wire and flux. They must undergo strict physical and chemical inspections before being put into use.
2. The head and tail of the strip are butted by single wire or double wire submerged arc welding, and automatic submerged arc welding is used for repair welding after rolling into a steel pipe.
3. Before forming, the strip is leveled, trimmed, planed, surface cleaned and conveyed and pre-bending.
4. The electric contact pressure gauge is used to control the pressure of the cylinder on both sides of the conveyor to ensure the smooth conveying of the strip.
5. Adopt external control or internal control roll forming.
6. The weld gap control device is used to ensure that the weld gap meets the welding requirements, and the pipe diameter, the amount of misalignment and the weld gap are strictly controlled.
7. Both internal welding and external welding use the American Lincoln welding machine for single wire or double wire submerged arc welding, so as to obtain stable welding specifications.
8. The welded seams are all inspected by an online continuous ultrasonic automatic flaw tester, which ensures 100% non-destructive testing coverage of the spiral welds. If there is a defect, it will automatically alarm and spray the mark, and the production workers can adjust the process parameters at any time accordingly to eliminate the defect in time.
9. Use an air plasma cutting machine to cut the steel pipe into single pieces.
10. After cutting into a single steel pipe, each batch of steel pipes must undergo a strict first inspection system to check the mechanical properties, chemical composition, fusion condition of the weld, the surface quality of the steel pipe and non-destructive testing to ensure that the pipe making process is qualified. Only then can it be officially put into production.
11. The parts with continuous sonic flaw detection marks on the welds shall be re-examined by manual ultrasonic wave and X-ray. If they are indeed defective, they shall be repaired and subjected to non-destructive inspection again until it is confirmed that the defects have been eliminated.
12. The tube where the strip butt welding seam and the T-joint intersecting with the spiral welding seam are located shall all be inspected by X-ray television or filming.
13. Each steel pipe is tested by hydrostatic pressure, and the pressure is radially sealed. The test pressure and time are strictly controlled by the water pressure microcomputer detection device of the steel pipe. The test parameters are automatically printed and recorded.
14. The pipe end is machined so that the verticality of the end face, the bevel angle and the blunt edge are accurately controlled.

Listing some notes You must know

• Oiled marking: Steel after passing wrer oiled to prevent corrosion,and according to user requirements for making.
• Leveling Milling: The flat steel anvil machine so that the origal curl,and then thouth the edge milling machine for two-sided steel milling,so as to meet the requirements of the plate width,plate edge parallelism and groove shape.
• Shear molding: The steel plate production line along the outer edge of the spiral curl into a tube.
• Butt cut: Double-sided submerged arc welding using advanced technology to pre-welding,internal welding,outside wilding.The welded steel pipe using a plasma-foot cut to specification length.

Why Choose our spiral welded pipe?