LSAW Steel Pipes

LSAW straight seam submerged arc welded steel pipe is a large-diameter welded steel pipe made from wide and thick steel plates through JCOE/UOE cold bending and double-sided submerged arc welding processes. It features a large pipe diameter, a wide range of wall thicknesses, high structural strength, and excellent dimensional accuracy. It is the core main material for offshore pipelines, pile foundations, risers, and platform structures, and is widely used in marine engineering fields with high pressure and high reliability requirements. 

Application scenario

1. All types of offshore pipelines, underwater gathering and transportation pipelines, long-distance submarine oil and gas transmission trunk pipelines;

2. Load-bearing structural components such as risers for offshore wind power and oil and gas platforms, substructure main legs, and steel pipe piles;

3. Pipeline and foundation materials for large-scale offshore wind power and grid connection projects like BalWin2 in the UK;

4. Pressure-bearing fluid pipelines, process pipelines under high/low temperature conditions;

5. Heavy steel structures and transportation pipelines for coastal areas such as ports and cross-sea projects. 

Main structure

The structure is made by rolling steel plates and forming with double-sided submerged arc welding. The welds are longitudinal straight welds, ensuring stable welding quality. The conventional outer diameters range from 508 to 1422 mm, with wall thicknesses ranging from 8 to 40 mm, and the maximum wall thickness can reach 60 mm. The single pipe length is 12 to 18.3 meters. Customized special pipe fittings such as variable-diameter pipes, elbows, and tees can be provided according to requirements. The pipe ends are processed with standard welding grooves or flange connection structures. The steel pipe body can be prefabricated with external and internal anti-corrosion coatings, and subsequent painting treatment can also be provided. Special steel grade pipe materials certified by DNV, such as IFD 450, can be produced. 

Corresponding product standards

International mainstream pipe material standards

- API Spec 5L: Pipeline-specific steel pipes, grade L245 to X80

- ISO 3183: Steel pipes for pipeline transportation systems, grade L245ME to X70ME

- EN 10219-1: Cold-formed structural pipes of non-alloy and fine-grained steels

- EN 10217 series: Pressure-bearing welded steel pipes (classification by normal temperature, high temperature, and fine-grained alloy steel)

DNV offshore pipeline steel certification specification