What pre-processing is required for seamless steel pipes?

Straight seam steel pipe is a type of welded steel pipe. It refers to a steel pipe with a weld seam parallel to the longitudinal direction of the pipe. Hot-rolled steel coils are formed into a cylindrical shape by a forming machine. Welding is performed using high-frequency current, the skin effect and proximity effect, or arc combustion beneath a flux layer. The edges of the pipe are heated and melted under a certain extrusion pressure, then cooled and formed. This type of pipe is widely used in industries such as petroleum, metallurgy, construction, coal mining, ports, and machinery for oil and gas transportation, low-pressure water and coal gas transportation, mine fluid transportation, belt conveyors, and automotive drive shafts.

 

 

Production Process for Piling Straight Seam Steel Pipes

 

1. Steel Plate Inspection: Before processing, the steel plates undergo ultrasonic testing to effectively prevent unqualified steel plates from entering the production line.

 

2. Cutting: The steel plates are milled on both sides using a milling machine. Since reducers are larger at one end and smaller at the other, the steel plates are also cut wider at one end and narrower at the other after cutting, ensuring the required plate width, edge parallelism, and groove shape.

 

3. Pre-bending: The plate edges are pre-bent using a pre-bending machine to meet curvature requirements. For thicker steel plates, a press can be used for pre-bending.

 

4. Forming: First, half of the pre-bent steel plate is rolled multiple times on a forming machine to form a "J" shape. The other half is then rolled into a "C" shape, and finally, an open "O" shape is created.

5. Pre-welding: After forming, the straight seam steel pipe for piling is welded using two-wire welding.

 

6. Internal Welding: Longitudinal multi-wire submerged arc welding (up to four wires) is used for welding the inside of large-diameter welded pipes.

 

7. External Welding: Longitudinal multi-wire submerged arc welding is used for welding straight seam steel pipes for piling.

 

8. Trimming: The entire welded steel pipe is trimmed to ensure the precise dimensions required by the customer and to improve the internal stress distribution of the pipe.

 

9. Testing: Based on customer requirements, the straight seam steel pipe for piling undergoes ultrasonic testing, X-ray testing, hydrostatic testing, and corrosion protection and coating.

 

Summary: This is a complete guide to seamless steel pipe applications. If you have any questions, please contact us immediately.