Straight Seam Welded Pipe Production Process

Straight seam welded pipe, commonly called ERW (Electric Resistance Welded) pipe, is manufactured from coiled steel strip (skelp). 

1. Uncoiling & Leveling: Steel coil is unwound and flattened.

2. Forming: Successive forming rolls progressively bend the strip into a cylindrical shape with the edges brought together.

3. Welding: High-frequency electric current (HFI ERW) or a laser beam is applied precisely at the meeting edges. Resistance heating instantly melts the edges, which forge together under pressure to create a continuous, solid-phase weld without filler metal.

4. Sizing & Cooling: Rolls calibrate the pipe to exact diameter and roundness, followed by cooling.

5. Cutting & Testing: The continuous pipe is cut to length. Non-destructive testing (e.g., ultrasonic) verifies weld integrity.

6. Finishing: Ends may be bevelled, and pipes undergo hydrostatic testing and coating if required. This efficient process produces pipes widely used in fluid conveyance, structural applications, and fencing.