API 5L steel line pipe delivery conditions

API 5L pipes, commonly used for oil and gas transportation, are available in various delivery conditions that influence their mechanical properties and suitability for specific applications.API 5L steel line pipe adopts different steel grades. As steel line pipes’ grades go higher, they have stricter control on the carbon equivalent control, and higher mechanical strength performance. The main delivery conditions for API 5L pipes include:

1. As Rolled (AR)

Pipes are produced by rolling without any additional heat treatment.

Typically has higher yield strength, but may have lower toughness compared to treated pipes.

2. Normalized (N)

The pipes are heated to a specific temperature and then air-cooled.

This improves the ductility, toughness, and uniformity of the material.

3. Quenched and Tempered (Q&T)

Pipes are heated to high temperatures, then rapidly cooled (quenched) and re-heated to a lower temperature (tempered).

Provides a higher strength-to-toughness ratio and is often used for higher grade pipes.

4. Thermo-Mechanical Controlled Process (TMCP)

Combines controlled rolling and cooling processes to enhance the strength and toughness of the steel without additional heat treatments.

Suitable for high-strength pipes with good weldability.

5. Cold-Expanded

Pipes undergo cold expansion after the final forming process, which can improve dimensional accuracy and increase yield strength.

6. Hot Finished

Pipes are formed at high temperatures and then cooled without further heat treatment, resulting in a product with less residual stress.

The delivery condition chosen depends on the specific requirements of the pipeline project, such as strength, toughness, and environmental factors.