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API 5L Line Pipe Explained: Standards, Strength, and Comparison with ASTM A106

In the world oil, gas, and energy infrastructure industry, API 5L is one of the most cited standards for steel pipes. Many customers also are comparing it with ASTM A106 seamless pipe and they ask if they can be used interchangeably.
Here are four frequently asked questions about API pipe followed by a brief outline of how Royal Steel Group assists international customers find dependable steel pipe solutions.

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ASTM A671 STEEL PIPES (1)

What Is an API 5L Pipe?

API 5L refers to the American Petroleum Institute specification for line pipe. Pipelines are the main application for it to transfer oil, gas, water and other fluids.

An api 5l line pipe is good for:
Long Distance Oil & Gas Pipelines
Onshore and Offshore Oil and Gas Pipeline Projects
High-Pressure Fluid Transmission Length Distance Oil & Gas Pipelines Onshore and Offshore Oil and Gas Pipeline Projects

API 5L steel pipe can be provided in the way of:
Seamless or welded
Different grades such as X42, X52, X60, X65, X70
Different gradations: X42, X52, X60, X65, X70
More Standard Availability Mill Size Ready Stock Diameters

These are all typically supplied as black carbon steel pipe as none of these are alloyed they do have good strength, ductility and price.

What Is API 5L Equivalent To?

There is no perfect one-to-one equivalent, but API 5L is often compared with standards such as:

ASTM A106
ASTM A53
EN 10208
ISO 3183

For example:
API 5L Grade B ≈ ASTM A106 Grade B (similar chemical and mechanical ranges)
Higher grades like X52, X60, X65 do not have direct ASTM A106 equivalents

API pipe is specifically designed for pipeline transportation, while ASTM standards often focus more on pressure vessels, boilers, and general piping systems.

What Is the Yield Strength of API 5L Grade Pipe?

The yield strength depends on the grade.

Common examples:
API 5L Grade B: about 245 MPa (35,500 psi)
API 5L X42: about 290 MPa
API 5L X52: about 360 MPa
API 5L X60: about 415 MPa
API 5L X65: about 450 MPa
API 5L X70: about 485 MPa

Higher “X” grades mean higher minimum yield strength, making api 5l steel pipe suitable for high-pressure and long-distance pipeline projects.

Is API 5L the Same as A106?

No, they are not the same, although they are often compared.

Main Differences:
API 5L is mainly for pipeline transportation of oil and gas
ASTM A106 seamless pipe is mainly for high-temperature and high-pressure service in boilers, power plants, and refineries
API 5L includes both welded and seamless pipes
A106 steel pipe is only seamless

In practice, API 5L Grade B and astm a106 seamless pipe Grade B are sometimes used interchangeably in low-risk projects, but technically they are designed for different applications.

Royal Steel Group – API & ASTM Pipes is Your Trusted Supplier

Having more than decades of experience in the field of global steel export, Royal Steel Group is specialized in trading in:
API 5L line pipe
API 5L steel pipe in different grades
API pipe for oil and gas industry
Black carbon steel pipe for general industrial use
ASTM A106 seamless pipe
A106 seamless pipe for high temperature service

Royal Steel Group offers:
Stringent Quality Control From Raw Material To The End Pipe
MTC and Third party inspection
Export experience to the Middle East, South East Asia, Africa, and South America
Technical Assistance in Choosing Between API 5L and ASTM A106

If you are seeking an international partner to supply rugged and reliable products such as api 5l line pipe for pipelines or astm a106 seamless pipe for high-temperature service, Royal Steel Group can assist global customers in selecting the material, fulfilling standards and providing dependable steel pipe solutions worldwide.

Contact for More Details:

WhatsApp: +86 136 5209 1506
Email: sales01@royalsteelgroup.com
Website: www.royalsteelgroup.com

 

ROYAL GROUP

Address

Kangsheng development industry zone,
Wuqing district, Tianjin city, China.

E-mail

sales01@royalsteelgroup.com

Phone

Sales Manager: +8613652091506

Hours

Monday-Sunday: 24-hour Service

Post time: Jan-21-2026