ERW Pipe vs. LSAW Pipe

ERW (Electric Resistance Welded) and LSAW (Longitudinally Submerged Arc Welded) are both types of straight seam welded pipes. Their main difference lies in the welding process.

ERW steel pipe:

Definition: ERW is a general term for electric resistance welded steel pipes, which are high-frequency resistance welded straight seam welded pipes.
Process characteristics: High-frequency resistance welding is used, and hot-rolled wide-band steel coils are used as raw materials.

Advantages and Disadvantages: It has high dimensional accuracy, uniform wall thickness and good surface quality. The welding process makes the welds shorter and able to withstand greater pressure. However, this process is usually only suitable for small and medium-sized thin-walled pipes.

Application fields: Widely used in urban gas, crude oil and refined oil transportation and other fields.

LSAW steel pipe:

Definition: LSAW refers to Submerged Arc Welded Steel Pipe.
Process characteristics: Adopt submerged arc welding process, using a single medium-thick plate as raw material.

Advantages and Disadvantages: High weld quality, high production efficiency, no arc light and less smoke pollution. It can produce large-diameter, thick-walled steel pipes with good high-pressure resistance, low-temperature resistance and corrosion resistance.
Application fields: Widely used in high-strength, high-toughness long-distance oil and gas pipeline projects such as pressure vessels, pipe fittings manufacturing, beams and columns, low-pressure fluids, and steel structure engineering.

In general, ERW steel pipes focus on small and medium diameter, thin-walled applications, while LSAW steel pipes are suitable for high-end needs of large diameters and thick walls.

Core Performance

Comparison Items	ERW pipe	LSAW pipe
Pipe diameter range	Mostly small and medium caliber (usually ≤610mm)	Mainly large diameter (≥1422mm)
Pressure resistance	Medium and low pressure (design pressure ≤ 10MPa)	Medium and high pressure (≥16MPa, depending on steel grade)
Weld toughness	The toughness of the weld area is slightly lower than that of the parent material	After heat treatment, the toughness of the weld is closer to that of the parent material.
Production efficiency	Continuous production, high efficiency, suitable for batches of small and medium diameter pipes	Single pipe production, low efficiency, suitable for customizing large diameter pipes

How to choose between ERW pipe and LSAW pipe

ERW pipes and LSAW pipes have their own advantages and disadvantages. How to choose in practical applications? This requires comprehensive consideration of many factors. If it is for urban gas transmission, the pipe diameter requirement is not large, and it is more sensitive to cost, and at the same time requires high dimensional accuracy and a certain pressure, then ERW pipe is a good choice; in large-scale oil and gas pipeline projects, if large diameter, thick wall, and high pressure and harsh environment pipes are required, LSAW pipes are more suitable.

When choosing, we must first clarify the pipe diameter required for the project. ERW pipes are generally suitable for small and medium diameters, while LSAW pipes perform well in large diameters. Secondly, we must consider the pressure that the pipeline is subjected to. When the pressure is high, the high-pressure resistance of LSAW pipes is more reliable. Furthermore, the environment is also an important factor. For example, in extreme environments such as high cold and seabed, the low-temperature resistance and corrosion resistance of LSAW pipes can better ensure the safety of the pipeline. In short, only by weighing the advantages and disadvantages of the two according to specific needs and working conditions can we make the most appropriate choice.

Read more: ERW Pipe vS Seamless Pipe: what's the Difference?