Steel coils are use to make ERW pipes; the coil is first uncoiled, followed by smoothing, cutting, and finally, electrically joining its two extremities to form a pipe.
Due to the advanced welding techniques used by ERW pipe manufacturers in recent years. ERW pipes have effectively replaced seamless pipes as an affordable and high-performing alternative (for example HFI and HFW, high-frequency welding). The technical advantage of seamless pipes over ERW pipes has gradually diminished as a result of these advancements in welding technology, making them interchangeable in at least some applications (low/medium pressure and temperature). Naturally, the inherent superior mechanical strength of steel billets over coils and plates will always be advantageous for seamless pipes.
LSAW PIPE (LONGITUDINAL SUBMERGED ARC WELDING)
Steel plates are cut, bent, and welded to form LSAW pipes (submerged arc welding) (JCOE process).
In the size range of 16 to 24 inches, LSAW pipes compete with seamless and ERW pipes, but are a “must-go” choice for pipelines larger than 24 inches (as 24 inches is the maximum size for commercial seamless pipes).
The longitudinal (with a single or double straight seam weld, DSAW). Spiral types of LSAW pipes are the two primary types (called, HSAW, SSAW, or SAWL pipe). As a result, DSAW and LSAW pipes differ in that DSAW pipes have seam welds on both the inside and outside of the pipe. Whereas LSAW pipes only have a seam weld on the outside surface.
The distinction between LSAW and ERW pipes is that while ERW pipes are Manufacture from steel coils, LSAW pipes are produce using steel plates.
Large-diameter API 5L LSAW pipes are use to efficiently move hydrocarbons over long distances in the oil and gas industry.
For non-critical applications, such as water transmission and distribution, HSAW/SSAW spiral weld pipes are use (not for oil & gas).