What is line pipe?, Sunny Steel Enterprise Ltd.
Home > About Us> Tech & Service

What is line pipe?

A Line Pipe is a high strength carbon steel pipe used for transporting crude oil, petroleum products, natural gas and water. It is a pipeline which carries only one type of fuel.

These pipes are made as per metallurgical specifications developed by API (American Petroleum Institute). Line pipes are manufactured in a wide range of pipeline diameter size ranging from 2 inches to 48 inches.

Line Pipes are manufactured under regulations specified by API. The standard used worldwide in the manufacturing of line pipes is API Specification 5L. This specification defines that the pipeline will be used to transport crude oil, petroleum products, natural gas or water. The pipeline manufacturing industries produce two types of line pipes, i.e., seamless line pipe and welded line pipe.

Welded line pipe are widely used for interstate natural gas pipelines. These pipelines are generally large diameter pipelines produced by forming steel plate into cylindrical shape and seam is closed by welding process. The quality of the welded seam is checked by using ultrasonic or radiological inspection method and pressure test is performed at each joints.

Seamless line pipes are manufactured from a cylindrical bar of steel and are heated to very high temperatures. When the pipe becomes red hot, it is then pierced with a probe to create necessary holes into it. This red hot cylindrical bar is run through rollers to produce proper wall thickness and diameter.

The American Petroleum Institute specification API 5L covers seamless and welded steel line pipe. This is steel pipe for pipeline transportation systems in the petroleum and natural gas industries. API 5L is suitable for conveying gas, water, and oil. Size range is limited only by manufacturer’s capabilities.

Specifications for API 5L adhere to the International Organization for Standardization ISO 3183, which standardizes pipeline transportation systems within the materials, equipment and offshore structures for petroleum, petrochemical, and natural gas industries. The technical committee authoring the standards recognized that there are two basic Product Specifications Levels (PSL) of technical requirements and therefore developed PSL 1 and PSL 2. PSL 1 is a standard quality for line pipe where PSL 2 contains additional chemical, mechanical properties, and testing requirements.

Inspection and Tests Performed:

Line pipes once manufactured undergo quality and inspection checks for steel chemistry, dimensional characteristics, strength and toughness.

  • API SPEC 5L – Chemical composition, Mechanical properties, Hydrostatic test, Dimensional testing, Visual inspection, Nondestructive inspection
  • API SPEC 5CT – Specification 5CT/ISO 11960, Specification for Casing and Tubing, Eighth Edition, Petroleum and natural gas industries-Steel pipes for use as casing or tubing for wells.



English Inglés SpanishEspañol
Sunny Steel Blog
Recommended products
Pipe fittings
Pipe fittings are used to connect pipes.
Welded steel pipes Weld steel pipes
We produce an extensive selection of weld steel pipe
Welded steel pipes Anti corrosion pipe
Anti-corrosio pipe is processed through the preservation
Ceramic-Lined Pipes
from a single spool piece to complete piping systems.
Pipe flanges
Pipe flange are a method of connecting pipes, valves.
Pipe Fitting Accessories
We are passionate in Stub Ends, Bolt Sets, Fasteners


About Sunny Steel

Our team are highly trained and experienced in servicing and producing all types of steel supplies. Whether you've got a large construction project, or need parts for industrial machinery, our team of steel fabrication consultants will ensure that your project is provided with the parts you need, when you need them.

Link exchange