Definition of Pipe
ERW pipe is produced using the electric resistance welding method. During this process, the edges of steel plates or coils are heated and fused together to form a seamless joint. ERW pipe is more durable than SAW pipe. Defects are also less likely to occur compared to the solvent process used in SAW pipe, and straight weld defects can be easily detected using ultrasonic reflection or visual inspection.
SSAW pipe, also known as spiral submerged arc welded pipe, is made using a spiral welding process. This method ensures a consistent and uniform weld, which contributes to the structural integrity of the pipeline. And the spiral welding process can create large diameter options.
LSAW pipe is made using a longitudinal welding process. The technology involves using a large plate that is cold formed into the desired shape before welding. The main difference between LSAW and SSAW pipe is the direction of the seam weld, which affects the pressure bearing capacity and the ease of manufacturing. LSAW is used for medium and high voltage services.
Forming process
ERW (straight seam resistance welding): ERW steel pipe is welded by melting steel strip by medium frequency heating. Hot-rolled wide steel coil is usually used as raw material, and it goes through pre-bending, continuous forming, welding, heat treatment, sizing, straightening, cutting and other processes.
SSAW (spiral submerged arc welding): SSAW steel pipe is welded by spirally curled steel plate, and the weld is spiral. Its forming process includes steel plate pretreatment, curling, welding, internal and external welding and other steps.
LSAW (straight seam submerged arc welding): LSAW steel pipe is made by unfolding and welding steel plate into straight seam, and then expanding the diameter. Its forming process includes steel plate pretreatment, curling, welding, expanding the diameter and other steps.
Weld seam form
ERW: The weld is straight, the weld is short, the dimensional accuracy is high, the wall thickness is uniform, the surface quality is good, and the pressure resistance is large.
SSAW: The weld is spiral and the weld is long, usually used for large diameter pipes.
LSAW: The weld is straight, similar to ERW, but the forming process is different.
LSAW steel pipe
