API 5L is a more comprehensive specification mainly developed for line pipes used in oil and gas industry; the range of strength grades is much wider. While the lower strength grades grades A & B are comparable to A106, the other grades have much higher strengths (e.g. X42, X56, X60,…etc). Also, the quality grades are more stringent when API 5L Line Pipe PSL2 is applied where as rolled grades are not acceptable and rework is not allowed. Moreover, particular attention is given to toughness and toughness tests for sour services and higher pressure/ temperature classes.
What is the difference between A53 and A106 pipes? To answer this question, we need first to recap what these standards are all about:
A last pipe specification that often overlaps with A53 / A106 is the API 5L Gr. B, which covers linepipes. These three specs are very close in terms of chemical composition, mechanical properties: some manufacturers actually mark the same lenght / budle of pipe with the three standards at the same time to indicate their interchangeability. For the same reason, it is also quite common that suppliers quote alternatively API 5L or A106 pipes if they receive an enquiry for A53 pipes.
That said, the main differences among A106 and A53 pipes are in terms of:
As a rule of thumb, A106 pipes are supplied when seamless execution is requested, A53 when welded execution is preferred for cost reasons.
|Standard||Grade||Chemical Composition %|
|API 5L||B(PSL-1)||>414||≥241||As clause a||–|
|DIN 1629||St 37.0||350-480||≥235||≥23||–|
|DIN 2448||St 44.0||420-550||≥275||≥19||–|
A53 Pipe vs A106 Pipe – (1) Scope
ASTM A53 is Standard Specification for Pipe, Steel, Black and Hot-Dipped, Zinc-Coated, Welded and Seamless.
ASTM A106 is Standard Specification for Seamless Carbon Steel Pipe for High-Temperature Service.
A53 Pipe vs A106 Pipe – (2) Applied Type of Pipe
A 53 can be welded seam or seamless depending on how it is specificed for purchase. It is a general steel pipe spec and covers galvanized pipe as well as black pipe.
A106 is a similar pipe in chemical composition but is intened for high temperature service (up to 750 Degs F). It is a seamless pipe.
At least in the US, there is usually A53 for welded pipe while A106 is seamless. If you ask for A53 in the US they will quote A106 as an alternate.
A53 Pipe vs A106 Pipe – (3) Chemical Composition
For example when we compare between A106-B and A53-B seamless from chemical composition point of view, we find that :
1. A106-B contains silicon, min. 0.10% where A53-B has zero%, and silicon is the important element for improving the heat resistance criteria.
2. A106-B contains manganese 0.29-1.06%, where A53-B 1.2%.
3. A106-B contains low sulfur and phosphorus, max. 0.035% where A53-B contains 0.05 and 0.045% respectively.
A53 Pipe vs A106 Pipe – (4) Mechanical Properties
|Grade A||Grade B||Grade C|
|ASTM A53||Tenside strength, min, psi (MPa)||48000(330)||60000(415)|
|Yield strength, min, psi (MPa)||30000(205)||35000(240)|
|ASTM A106||Tenside strength, min, psi (MPa)||48000(330)||60000(415)||70000(485)|
|Yield strength, min, psi (MPa)||30000(205)||35000(240)||40000(275)|
Other difference for A53 Pipe vs A106 Pipe
Because they have different scope and specify different type of pipe, then the manufacturing process and required quality control test and inspection will be different to each other. Leave a comment if you have specified opinion.