Line Pipe

Pipe formed without a weld seam by piercing and elongating a heated solid billet, offering uniform circumferential properties favored for higher-pressure and sour-service lines. Common in smaller and intermediate diameters where seamless mills are economical.

Pipe made by cold-forming flat skelp into a cylinder and joining the longitudinal seam with electric resistance (high-frequency) welding without filler metal. Widely used for small- to mid-diameter gathering and transmission lines under API 5L.

Large-diameter pipe formed from plate (UOE or JCOE process) with a straight longitudinal seam joined by submerged-arc welding, typically double-sided (DSAW). Used for high-pressure, large-bore transmission trunk lines.

Pipe produced by helically forming a continuous coil or strip and submerged-arc welding the spiral seam. Economical for large-diameter, lower-to-moderate-pressure water, gathering, and transmission service.

Standard carbon and carbon-manganese steel line pipe in API 5L grades B through X80, selected by yield strength for non-corrosive or inhibited service. The baseline product for most oil, gas, and water transmission.

Line pipe built from or internally lined with corrosion-resistant alloys (such as stainless or nickel-based alloys) as metallurgically bonded clad or mechanically lined pipe for highly corrosive, CO2, or sour fluids. Combines a carbon steel structural backing with a CRA wetted layer.

Corrosion-resistant alloy line pipe covered by API 5LC (CRA pipe) and API 5LD (CRA-clad or -lined pipe) for service in corrosive production environments. Used where carbon steel with inhibition cannot meet life-of-field corrosion requirements.

Fabricated structural steel pipe produced to API Spec 2B for fixed offshore platform tubular members and other load-bearing structures, distinct from pressure-transmission line pipe. Sized and welded for structural loading rather than internal fluid pressure.