Overview
ASTM B221/B221M-21 covers aluminum and aluminum-alloy extruded bars, rods, wire, profiles and general-purpose tubes in listed alloys and tempers. Procurement must combine alloy-temper with the exact extrusion drawing, form, unit document, tolerances, straightness, surface, heat treatment and pressure or structural exclusions.
Designation and acceptance
B221 is a broad general-purpose extrusion specification. A profile drawing controls geometry but does not select alloy, temper or acceptance properties; conversely an alloy-temper does not define die details, tolerances or finish. Tube listed under B221 is general-purpose and should not be assumed to meet B241 pressure integrity or B429 structural-pipe requirements.
Members and selection
| Designation | Selection context |
|---|---|
| Bar / rod / wire | Specify cross-section, temper, straightness and end-use machining or forming. |
| Solid profiles | Use a controlled drawing for wall, ribs, radii, tolerances and critical dimensions. |
| Hollow profiles | State seam/porthole-die acceptance, wall, cavity and pressure exclusion. |
| General-purpose tube | Order by exact OD/shape and wall; do not infer pressure-service integrity tests. |
Comparison framework
| Criterion | Decision context |
|---|---|
| B221 vs B241 | B221 tube is general-purpose; B241 covers seamless pipe and seamless extruded pressure tube. |
| Profile vs structural shape | A geometric profile is not automatically a code-listed structural product. |
| Alloy vs temper | Both form one material identity and affect extrusion, strength, forming and corrosion. |
| Standard vs die drawing | B221 governs material acceptance while the drawing controls unique geometry and critical dimensions. |
Performance
- Acceptance under ASTM B221 Aluminum Extrusions depends on the ordered product branch, delivered condition, geometry and specified test basis rather than the standard number alone.
- Die lines, twist, bow, wall variation, porthole seams and quench history can govern finished-part performance.
- Service suitability remains an engineering decision: a common 6061 or 6063 callout does not define profile geometry, temper evidence, finish or pressure/structural qualification.
Orderable product scope
- Solid and hollow extruded profiles cut to length.
- Extruded bar, rod and wire products.
- General-purpose round or shaped extruded tube.
Processing
- Coordinate die design, extrusion direction and critical dimensional capability before production.
- Qualify press quenching or later heat treatment for the specified temper.
- Define anodizing, powder coating, machining and joining allowances on the actual profile.
Applications
- Architectural, transportation and equipment profiles.
- Machined extruded bar and general-purpose tubular components.
- Frames, rails, heat sinks and custom sections after design qualification.
Selection
- Confirm that ASTM B221 Aluminum Extrusions 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 B221/B221M-21, unit document, exact alloy-temper and product form.
- Provide controlled profile drawing, critical dimensions, tolerances, length, quantity, straightness and twist.
- Define surface class, die-line limits, seam disclosure, heat-treatment evidence and fabrication/finish plan.
- Require inspection report, lot identity, protected contact surfaces, separators and bundle packaging.
Sources and review
ASTM International · 2021, active
ASTM International · Reapproved 2023, active
ASTM International · 2020a, active