Aerospace Aluminum Extrusions: Profiles, Specs, Dies and Lots

Updated October 13, 2026

Extrusion types and where they are used

Extrusions give you a constant cross section in long lengths, which is why they show up as stringers, rails, frames and channels. The Aluminum Association's terms guide sorts them by cross section, and the categories matter because they change how the die is built and what defects to look for.

Hollow profiles and tubes made on a porthole or bridge die carry longitudinal extrusion seams where the metal split around the mandrel and welded back together inside the die. The guide notes these seams are usually invisible until the surface is etched or anodized. Seamless hollows and tubes, with no such line junctures, are a different product, and that distinction is central on our aerospace tubing page.

Standard profiles versus custom profiles

Use a standard profile when one exists that the design can live with; use a custom profile when the part count, weight saving or machining saved pays for a die and a production run. That is mostly a quantity and schedule decision.

• Standard profiles are angles, channels, tees, zees, I and H sections, bar and tube in common sizes. A die already exists, so the question is whether the alloy and temper you need are produced on it and whether any stock is certified to your spec.
• Custom profiles need a new die. Expect a one-time die charge, a die design review, a trial run and first article inspection of the profile before production. The cost and time depend on the size of the circle that contains the profile, wall thickness, tongue ratios on semi-hollows and whether it is hollow, since a porthole or bridge die is more complex than a solid die.
• Die ownership and changes. Settle who owns the die, how long the extruder keeps it, and what happens when the drawing changes. A dimension change that moves a wall usually means a new die, not a correction.
• Minimum runs. Extruders run by billet and press time, so a custom profile often comes with a minimum quantity by weight or length. Surplus from earlier runs of the same profile, with intact certs, can bridge a small need.

Before committing a custom profile, ask a machinist whether the same part is cheaper from plate or bar. Our plate and sheet and bar and rod pages cover those routes.

Have a part like this?Send it in under a minute. A person replies within 1 business day.

The specifications that govern aerospace extrusions

Buy extrusions to the spec on the drawing. The structure is a general specification plus alloy detail documents, with AMS detail specs for the common aerospace tempers. Status below is what we found on SAE's site and on EverySpec copies of DLA cancellation notices.

A drawing that still cites a federal QQ-A-200 sheet needs a decision from your engineering authority on the AMS replacement before you buy. Do not let a supplier pick the substitute.

Tempers for extrusions: T6, T6510 and T6511

Heat-treated extrusions are stress relieved for the same reason plate is, and the temper suffix tells you which relief the material received. AMS 4154 covers 7075 extrusions in T6, T6510 and T6511 and describes the relief as stretching when required. T6 has no stress relief step. Of the two relieved tempers, the T6511 version may also be straightened after stress relief, which is how long profiles are brought back within straightness tolerance.

• For profiles that will be machined heavily, a stretched temper reduces movement after machining.
• For long, thin profiles, T6511 is often the practical choice because a little straightening after stretch keeps the profile within straightness tolerance.
• Where stress corrosion governs, the drawing may call an overaged temper instead. The aluminum alloys page explains the stress corrosion side, so it is not repeated here.

The Aluminum Association guide also describes two extrusion-specific effects worth knowing. The extrusion effect raises longitudinal properties in some alloys because the core stays unrecrystallized. Peripheral coarse grain is a recrystallized band at the surface that can have lower properties than the core. Both are reasons to machine extrusions with the drawing's grain direction in mind and to let the spec, not habit, decide the temper.

Tolerances: ANSI H35.2 and what to tighten

Standard extrusion tolerances come from ANSI H35.2, the Aluminum Association's dimensional tolerance standard for mill products, which aerospace and government specs use as their basis. Extrusion tolerances cover more than wall thickness: cross section dimensions, straightness, twist, flatness of surfaces, angularity and corner radii all have tables, and the allowed values depend on the size of the profile and whether a dimension is across metal or across a void.

• Identify the dimensions that matter. Mark functional features on the profile drawing so the extruder and the inspector know which tolerances to hold tighter, and accept the standard table elsewhere.
• Precision profiles cost more. The Aluminum Association guide calls a profile that meets special form and dimension tolerances a precision profile. Tightening every dimension raises die and run cost.
• Twist and straightness show up on long parts. Specify them per foot or per length on the drawing if a stringer or rail must sit flat in an assembly.
• Cut length. Extrusions ship in mill lengths or cut lengths. State cut length and tolerance, and whether ends need to be square for fit-up.

Heat treatment lots and traceability

Extrusion test results apply to a heat treatment lot, so the cert must identify the lot, and every piece in your bundle must trace to it. The Aluminum Association guide defines a heat treatment lot as product of the same alloy, form and size processed the same way in one furnace load, and notes that for continuous furnaces the output over a set time can be treated as one lot.

• Ask for the cast or heat number and the heat treatment lot on the cert and on the material.
• Mixed lots in one bundle are common on long runs. Accept them only if each piece is marked and each lot has results.
• Extrusions cut to length by a distributor need the lot transferred to every piece, the same discipline described for bar and plate.
• Falsified extrusion test results have caused real launch failures; the case is summarized on our certified material page, and it is the reason to buy extrusions only from sources with a traceable quality system.

Materials and the trade-offs

Finishes change dimensions and appearance, and hollow seams can show after anodizing. Coating choices are covered in the anodizing and chemical conversion coating references.

Ordering checklist for extrusions

• Profile drawing or standard profile designation, with critical dimensions identified
• Alloy, temper and specification with revision, for example 7075-T6511 to AMS 4154
• Tolerance basis, ANSI H35.2 or drawing, plus any straightness, twist or flatness limits
• Mill length or cut length with tolerance and end condition
• For custom profiles: die charge, die ownership, trial run and first article of the profile
• Cert with cast number and heat treatment lot, lot marking on every piece, and the cutter's C of C
• Seamless or porthole construction for hollows and tube where the drawing specifies it
• Packaging that protects long lengths from bending and surface damage; see crating and packaging

Counterfeit and quality risks, and how to receive extrusions

The risks are falsified mechanical results at the source, wrong temper, commercial alloys sold as aerospace alloys and look-alike profiles from a different die. Check the profile against the drawing at several points along the length, verify temper with conductivity and hardness, confirm the lot on every piece matches the cert, and inspect hollows for seam defects after any etch or anodize. Our receiving inspection guide and counterfeit avoidance process cover the rest.

How we source aluminum extrusions

We do not hold extrusions, own dies or publish prices. For standard profiles we source certified stock through mills, service centers and distributors, or certified surplus when the paperwork supports it. For custom profiles we take your drawing to extruders whose capability fits the size and alloy, manage the die, trial and first article steps, and flow down the spec, temper, tolerance and lot requirements.

Extrusions usually become machined or welded parts, so the material, cut, machining and finishing can sit on one purchase order. GSE frames built from extrusions are covered on our ground support equipment page. The rest of the stock family is on the raw material category.

Request aluminum extrusions

Send the profile drawing or standard designation, alloy, temper, specification, lengths and quantities through the certified material request form. For a custom profile, include annual quantity and which dimensions are critical, since that is what decides whether a die makes sense. A person replies within one business day, and rush requests are prioritized. Use our confidentiality process for proprietary profile drawings.

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Part, quantity and date are enough to start. Drawings and the mutual NDA follow by reply, and controlled programs never send technical data through this site.

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Related

• Aerospace Plate and Sheet: Thresholds, Tempers, Tolerances and Blanks
• Aerospace Tubing: Seamless and Welded Tube by Specification
• Buying Certified Aerospace Material and Surplus Drops
• Ground Support Equipment Fabrication for Launch and Spacecraft Programs

Sources

• SAE AMS-QQ-A-200: Aluminum Alloy, Bar, Rod, Shapes, Structural Shapes, Tube and Wire, Extruded: General Specification
• EverySpec: QQ-A-200/11E Notice of Cancellation
• EverySpec: QQ-A-200/3F (2024 extruded), cancelled
• SAE AMS 4150: Aluminum Alloy Extrusions and Rings, 6061-T6
• SAE AMS 4154: Aluminum Alloy Extrusions, 7075-T6, T6510, T6511
• Aluminum Association GAG Guidance Document 001: Terms and Definitions
• ANSI H35.2 overview (aluminum mill product tolerances)
• Xometry: 6061 T651 vs T6 and T6511