Overview
ASTM B241/B241M-22 covers aluminum and aluminum-alloy seamless pipe and seamless round extruded tube intended for pressure applications. The buying identity includes pipe versus tube, alloy-temper, hollow-ingot die-and-mandrel route, NPS or exact OD/wall, length, heat treatment, leak testing, ends and code requirements.
Designation and acceptance
B241 distinguishes standard-size seamless pipe from seamless extruded tube, including nonstandard alloy-temper-size combinations. Both are produced through a hollow-ingot die-and-mandrel route, but pipe and tube use different dimensional conventions. Material compliance does not provide fittings, weld procedures, corrosion allowance or pressure-system design approval.
Members and selection
| Designation | Selection context |
|---|---|
| Seamless pipe | Order by standard pipe size and wall basis accepted by the design. |
| Seamless extruded tube | Order by exact OD and wall for pressure use, including nonstandard combinations. |
| Heat-treatable alloys | State T temper and heat-treatment evidence; consider welding effects. |
| Non-heat-treatable alloys | State O/H temper, forming needs and service-corrosion basis. |
Comparison framework
| Criterion | Decision context |
|---|---|
| Pipe vs tube | Dimensional identity and tolerances differ even when alloy and extrusion route match. |
| B241 vs B221 | B241 supplies seamless pressure-product controls; B221 tube is general-purpose. |
| Extruded vs drawn | B241 is extruded; B210 adds drawing and its own dimensions/test branches. |
| Material vs system | B241 does not qualify valves, fittings, welds, design pressure or fluid compatibility. |
Performance
- Acceptance under ASTM B241 Aluminum Pipe and Tube depends on the ordered product branch, delivered condition, geometry and specified test basis rather than the standard number alone.
- Extrusion defects, wall variation, temper loss at welds and unsuitable fluid chemistry can govern integrity.
- Service suitability remains an engineering decision: seamless construction and mill tests do not replace system pressure design, joining qualification or corrosion assessment.
Orderable product scope
- Standard-size seamless aluminum pipe.
- Round seamless extruded pressure tube by OD and wall.
- Cut or random lengths with plain, bevelled or specified ends.
Processing
- Qualify bending, flaring and welding for alloy, temper and wall thickness.
- Protect the bore from chips, steel contamination, moisture and aggressive cleaning residues.
- Track heat/lot and heat-treatment identity through cutting and pressure-system fabrication.
Applications
- Aluminum pressure and fluid-transfer piping where B241 is approved.
- Seamless extruded pressure tube for process or equipment assemblies.
- Lightweight corrosion-resistant systems after media and code qualification.
Selection
- Confirm that ASTM B241 Aluminum Pipe and Tube covers the required product form and manufacturing or coating route before comparing quotations.
- Select the grade, alloy, temper, coating or delivered condition from service, fabrication and the required acceptance evidence; never infer it from a trade name.
- Require a written technical comparison and responsible-engineer approval before substituting another standard, product route or condition.
Procurement
- State ASTM B241/B241M-22, seamless pipe or seamless extruded tube, alloy and temper.
- State NPS or OD, nominal/minimum wall basis, length, quantity, tolerances and ends.
- Define heat treatment, tensile and leak/pressure tests, surface/bore cleanliness and supplementary examination.
- Require inspection report, heat/lot traceability, capped ends and contamination-safe dry packing.
Sources and review
ASTM International · 2022, active
ASTM International · Reapproved 2023, active
ASTM International · 2020a, active