Article
ASTM A106, ASTM A53 and API 5L all cover carbon steel pipe, and their Grade B versions have similar chemistry and strength. In a stockyard they can look identical. They are written for different jobs, though, and a project specification usually names one for a reason.
ASTM A106: high-temperature service
A106 covers seamless carbon steel pipe for high-temperature service. It is the usual specification for refinery, petrochemical and power plant process lines, boiler and steam piping. Grades A, B and C are available; Grade B is by far the most common.
- Seamless only.
- Grade B: tensile strength 415 MPa minimum, yield strength 240 MPa minimum.
- Requires a minimum silicon content (killed steel), which suits high-temperature use.
ASTM A53: general purpose
A53 covers seamless and welded pipe for mechanical and pressure applications and ordinary uses in steam, water, gas and air lines. It has three types:
- Type F: furnace butt welded. Grade A only, for low-pressure use.
- Type E: electric resistance welded.
- Type S: seamless.
A53 Grade B has the same minimum tensile and yield strength as A106 Grade B, but it is not intended for high-temperature service, and it is often used for structural and utility work.
API 5L: line pipe
API 5L is the specification for line pipe used to carry oil, gas and water in pipelines. It covers seamless and welded pipe across a wide range of strength grades, named by their minimum yield strength in thousands of psi: Grade B, X42, X52, X60, X65, X70 and above.
API 5L also has two product specification levels:
- PSL1: the standard quality level.
- PSL2: tighter chemistry and carbon equivalent limits, a maximum as well as a minimum yield strength, mandatory impact testing, and full traceability. Required for most gas and sour service pipelines.
Compared
| ASTM A106 Gr B | ASTM A53 Gr B | API 5L Gr B | |
|---|---|---|---|
| Main use | High-temperature process piping | General pressure and utility piping | Pipelines |
| Manufacture | Seamless | Seamless or ERW | Seamless or welded |
| Min. tensile | 415 MPa | 415 MPa | 415 MPa |
| Min. yield | 240 MPa | 240 MPa | 245 MPa |
Triple-certified pipe
Because the requirements overlap, many mills produce seamless carbon steel pipe that meets all three standards at once and certify it as ASTM A106 Gr B / ASTM A53 Gr B / API 5L Gr B. For a buyer, that pipe satisfies whichever of the three a drawing names. It does not satisfy API 5L PSL2 unless the certificate says so, because PSL2 has extra tests.
How to choose
- Process plant, steam or elevated temperature: A106.
- Utilities, water, air, structural: A53 is usually enough.
- Oil and gas pipelines: API 5L, with the grade and PSL from the pipeline specification.
- Low temperature, below about minus 29 °C: none of these; see ASTM A333.
See ASTM A106 Grade B seamless pipe and all pipes and tubes.
Frequently asked questions
What is the main difference between A106 and A53?
A106 is seamless pipe for high-temperature service, while A53 can be seamless or welded and is used for general and lower-temperature service.
Can one pipe meet A106, A53 and API 5L?
Yes. Triple-certified pipe meeting A106 Gr B, A53 Gr B and API 5L Gr B is common.
What is API 5L used for?
Line pipe for oil and gas transmission pipelines, with PSL1 and PSL2 levels.
Key takeaways
- A106 = seamless, high temperature; A53 = general purpose.
- API 5L = line pipe for pipelines.
- Triple-certified pipe can satisfy all three.
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Sawariya Metal Industries supplies stainless steel pipes, flanges and buttweld pipe fittings from Mumbai to buyers in India and overseas. Send your size, grade, standard and quantity through our enquiry form and we will reply with a clear quotation and the test documents you need. You can also browse our stainless steel pipes, flanges and buttweld fittings.