Large diameter LSAW steel pipe production process

Large Diameter LSAW Steel Pipe refers to a type of pipe used for transporting fluids and gases. "LSAW" stands for Longitudinal Submerged Arc Welding, which is a method of welding used to produce these pipes. Here are the key features and details about large diameter LSAW steel pipe production process.

Plate Probe:

After entering the production line, the large-diameter submerged arc welded steel pipe joints undergo full-board ultrasonic testing.

Milling:

A milling machine mills the edges of the plate on both sides to meet the required plate width, ensuring the plate sides are parallel and have the correct groove shape and degree.

Pre-curved Side:

A pre-bending machine is used to pre-bend the plate edges, ensuring the edges meet the required curvature.

Forming:

The pre-bent plate undergoes several pressing steps in a JCO forming machine. First, it is pressed into a "J" shape, then into a "C" shape, and finally into the "O" shape.

Pre-welding:

After forming, the straight seam welded steel pipe is continuously welded using gas welding (MAG).

Inside Weld:

A tandem multi-wire submerged arc welding system (up to four wires) is used to weld the inside of the straight seam welded steel pipe.

Outside Weld:

The outside of the LSAW steel pipe is welded using a tandem multi-wire submerged arc welding system.

Ultrasonic Testing:

100% inspection of the weld and both sides of the base material is conducted using ultrasonic testing on the inside and outside of the straight seam welded steel pipe.

X-ray Inspection:

An industrial TV inspection using an image processing system ensures 100% detection sensitivity for the welds on both the inside and outside.

Expansion:

The steel pipe undergoes expansion to improve size precision and stress distribution.

Hydraulic Test:

Each steel pipe is tested by a hydraulic test machine to ensure it meets the standard test pressure requirements. The machine has automatic recording and storage capabilities.

Chamfering:

After inspection, the steel pipe ends are processed to meet beveling size requirements.