Longitudinal Submerged Arc Welded (LSAW) steel pipe is a type of welded steel pipe used in various applications, including in the oil and gas industry, construction, and infrastructure projects.
Large steel plates are cut into specific dimensions based on the desired pipe size.
The edges of the plates are then prepared for welding. This often involves beveling to create a V-shaped groove for the weld.
The prepared plates are shaped into a cylindrical form through a process called cold forming or UOE (U-ing, O-ing, and expanding).
In the UOE process, the plate is first U-shaped, then O-shaped, and finally, the edges are expanded to achieve the desired diameter.
The longitudinal seam of the pipe is welded using the submerged arc welding (SAW) process. This involves placing the welding electrode beneath a layer of granular flux to create a protective environment for the welding arc.
The arc melts the edges of the plates, and the molten material solidifies to form a strong welded joint along the length of the pipe.
Various quality control measures, including non-destructive testing (such as ultrasonic or X-ray inspection), are conducted to ensure the integrity of the weld and the overall quality of the pipe.
Some LSAW pipes may undergo heat treatment to relieve residual stresses and improve the mechanical properties of the steel.
The resulting LSAW steel pipe has a longitudinal seam weld, distinguishing it from other types of welded pipes like ERW (Electric Resistance Welded) pipes or SSAW (Spiral Submerged Arc Welded) pipes. LSAW pipes are known for their high-strength and ability to withstand high pressures, making them suitable for applications such as oil and gas transportation, structural components, and water pipelines. The longitudinal seam provides a more consistent wall thickness along the pipe's length, contributing to its structural integrity.
