2011 aluminum
Temper- and product-specific reference for free-machining 2011 aluminum, composition, property data and processing limits.
Tags: materials, aluminum, machining, wrought-alloys
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Specify alloy, temper and product together
Aalco lists 270 MPa minimum proof stress, 320 MPa minimum tensile strength and 10% minimum elongation A for its 2011-T3 bar range, up to 200 mm diameter or 60 mm across flats. It cites BS EN 755-2:2008 and labels the figures indicative. Kaiser's typical T3 values below use a separate basis. Aalco bar properties
2011 is a copper-bearing wrought aluminium alloy used for machined components, including repetition-turned parts. Its attractiveness is machining productivity and chip control, rather than a universal balance of corrosion resistance, forming and joining performance. Aalco identifies its T3 rod/bar product as a free-machining alloy suited to automatic lathes. Aalco 2011 T3 rod and bar
Temper describes the processing condition. T3 includes solution heat treatment, cold work and natural ageing; T8 includes solution treatment, cold work and artificial ageing. Additional digits can identify further processing variations. They are part of the material identity, not optional suffixes. Aalco temper glossary
Chemistry and sourcing implications
Kaiser's rod/bar technical sheet KA-RBH-2011-8.10 lists composition limits by mass: 5.00–6.00% copper, 0.20–0.40% lead and 0.20–0.60% bismuth, with limits on silicon, iron, zinc and other elements. These are composition ranges, not the measured chemistry of every delivered heat. Kaiser 2011 technical data, p. 2
The deliberate free-machining additions matter when purchasing. Conventional 2011 with that chemistry is not lead-free. If the drawing, customer or application imposes a substance restriction, obtain a lot-specific composition/certification and an application-specific supplier declaration. Do not interpret a generic catalog description as approval for a regulated end use.
Kaiser's sheet contains a historical statement that its lead maximum changed effective May 1, 2009, and directs readers to the material certificate when in doubt. That dated statement is not a current universal compliance determination. Specify the actual permitted composition and applicable customer requirements, including treatment of older stock, rather than purchasing on the phrase “compliant alloy” alone. Kaiser composition footnote
Typical properties versus required limits
Kaiser explicitly labels the following rod/bar values typical, with tensile data based on a 0.500-inch-diameter specimen:
| Temper | Ultimate tensile strength | Yield strength | Elongation over 4D |
|---|---|---|---|
| T3 | 379 MPa | 296 MPa | 15% |
| T8 | 407 MPa | 310 MPa | 12% |
These are reference values, not minimum acceptance values or design allowables. The sheet lists ASTM B211 and AMS-QQ-A-225/3 for cold-finished product; confirm the required specification and applicable revision for the purchase. The document identifier is reproduced as printed rather than assigning a publication date from a search result. Kaiser technical data, pp. 1–2
Design assessment also needs the actual load case, temperature, fatigue, geometry, manufacturing history and applicable design rules. A tensile-test value alone does not establish allowable stress for a notched, threaded or cyclically loaded part.
Machining and dimensional control
2011 is a candidate when extensive turning, drilling and detailed machining dominate the route. Validate chip evacuation, tool life, surface finish and burrs on representative stock and geometry. A favourable machinability rating supplies no universal cutting speed, feed or coolant recipe.
Keep temper and stock condition attached to the machining record. Changing to another temper or a nominally similar free-machining alloy is a material change requiring review of the finished part. Likewise, machining a thin wall from a larger bar needs a dimensional-stability plan; excellent machinability is not evidence that removal of material cannot distort a part.
For a meaningful trial, record supplier/heat, stock size, tooling, cutting conditions, coolant, operation order and inspection temperature. Check difficult features and the final released part, not just an early operation while it is constrained in the chuck.
Joining, corrosion and finish
Aalco describes 2011 as having poor corrosion resistance and extremely poor weldability, recommending against welding. Its use for a machined component should not silently expand into a welded assembly route. Select another material or develop an explicitly approved joining process where joining is essential. Aalco 2011 fabrication guidance
Aalco's broader fabrication guidance identifies 6262 T9 as a possible alternative where greater corrosion resistance is needed while retaining strong machining performance. Hydro also describes 6262 as a specialised machining alloy, with joining characteristics improved over 2011 but below 6061. Neither statement establishes a direct substitution: check strength, composition, finish, dimensions and application requirements. Aalco aluminium fabrication, Hydro 6262
Where a protective finish is required, specify the coating process, coverage, dimensional allowance and acceptance criteria. Anodising a sample successfully does not establish decorative colour consistency, sealing performance or suitability for an aggressive environment. Qualify the finished assembly, including contact with other materials, for its actual service.