Different manufacturing types of API 5L pipes

The API 5L specification outlines two main manufacturing methods for pipes: welded and seamless. This article will introduce different manufacturing typesandmanufacturing evolutionof API 5L pipes.

Welded Pipes:

- ERW (Electric Resistance Welded): Primarily used for pipes with diameters under 24 inches. It is a cost-effective method for producing medium to small-diameter pipes.

- DSAW/SAW (Double Submerged Arc Welded / Submerged Arc Welded): These methods are typically employed for larger diameter pipes, offering an alternative to ERW for increased strength.

- LSAW (Longitudinal Submerged Arc Welded): Suitable for pipes with diameters up to 48 inches, often produced using the JCOE process for precise pipe formation.

- SSAW/HSAW (Spiral Submerged Arc Welded / Helical Submerged Arc Welded): Commonly used for larger diameter pipes, up to 100 inches, where the spiral welding technique offers flexibility in pipe sizes.

Seamless Pipes:

- Hot Rolled and Cold Rolled Seamless Pipes:

Seamless pipes are typically used for smaller diameters, especially under 24 inches. However, larger seamless pipes can also be produced through hot rolling, with diameters reaching up to 20 inches (508 mm). For pipes larger than this, a hot-expanding process allows diameters up to 40 inches (1016 mm).

API 5L Pipe Manufacturing Evolution:

Historically, in addition to seamless and ERW, furnace lap-welded pipes were also produced under the API 5L standard, though this method was phased out in 1962. As technology has advanced, improvements in steel plate manufacturing and welding processes have made ERW and SAW pipes the dominant methods for pipeline construction. Especially for large-diameter applications, SAW pipes offer cost efficiency and uniformity, making them highly favored in oil and gas pipelines.