2A11 Aluminium Bar and Rod

What is 2A11 aluminium?

2A11 belongs to the original family of duralumin alloys: about 4 % copper with smaller amounts of magnesium and manganese, strengthened by solution treatment and natural ageing. Under the older naming system it was called LY11, which is still printed on many drawings and certificates.

The alloy fills the middle ground of the 2xxx bar range. It is stronger than 6061 and far stronger than the 5xxx alloys, but a little below 2A12 and 2024, which carry more magnesium. In exchange it is slightly more ductile in the freshly quenched state, which is why it has long been used for rivets, bolts and parts that are upset or formed before ageing.

As bar and rod, 2A11 is mainly bought for machining: turned shafts and pins, bushings, hydraulic and pneumatic fittings, instrument parts, brackets, jigs and moulds. It cuts cleanly with short chips in the T4 temper, holds thread form well and takes anodising for protection. Like all high-copper alloys, it has only fair corrosion resistance and should be protected when it will see moisture or salt.

2A11 chemical composition (wt %)

Limits below follow GB/T 3190. The 2017 and 2017A columns show how close the international alloys are; the main difference is that 2A11 allows a slightly higher copper range.

2A11 contains no lead, bismuth or tin. Free-machining additions belong to alloys such as 2011 and 2011B, not to 2A11. If a supplier sheet mentions them, check it against GB/T 3190.

2A11 mechanical and physical properties

Specified minimum tensile, yield and elongation values for 2A11 extruded bar are set in GB/T 3191 and vary with diameter and temper; the mill test certificate reports the values for your lot. The table below gives typical values for orientation only. Because the chemistry is so close, published typical data for 2017-T4 is a good guide.

For the annealed O temper, the standard caps tensile strength rather than setting a minimum, because the purpose of the condition is softness for forming. A certificate showing a high tensile figure for O bar would indicate incomplete annealing.

2A11 tempers and heat treatment

2A11 standards and international equivalents

These are nearest equivalents, not identical alloys. Copper limits differ slightly, so a drawing that specifies 2A11 should be supplied as 2A11 unless the design authority accepts 2017 or 2017A in writing. Where both are acceptable, dual certification is often possible because many lots fall inside both sets of limits.

2011 is sometimes quoted as an equivalent to 2A11. It is not: 2011 is a free-machining alloy with lead and bismuth and a different strength profile. Use 2017 / 2017A as the comparison.

2A11 bar forms, sizes and weights

Standard lengths are typically 2.5 – 6 m, or cut to your length. Weights for solid round 2A11 bar at about 2.80 g/cm³:

Tolerances, coarse grain ring and inspection

Two quality points matter most on extruded 2A11 bar. The first is the coarse grain ring: a band of recrystallised, coarse grains near the surface that forms during extrusion and solution treatment. It lowers fatigue strength and can show as orange peel after anodising. Aerospace and fastener orders normally set a maximum ring depth, and machining allowance should remove it from critical surfaces. The second is straightness, which stretch straightening after quenching controls and which also relieves residual stress.

• Diameter tolerances to GB/T 3191, EN 755-3 or ASTM B221 for extruded bar; cold-finished bar is held tighter to EN 754-3 or ASTM B211
• Chemical analysis by spectrometer for each cast
• Tensile testing and hardness to confirm temper
• Coarse grain ring depth by macro-etching a cross-section, where specified
• Ultrasonic testing for internal discontinuities on larger diameters or when the order calls for it
• Visual and dimensional checks, with heat and lot traceability on every bundle

Machining, joining and finishing 2A11

2A11 compared with 2A12, 2017, 2024 and 6061

Choose 2A11 when you need more strength than 6061 in a machined part that will not be welded and the drawing calls for the GB alloy. Move up to 2A12 or 2024 for higher fatigue-critical loads, or to 7075 for maximum strength. Where weldability and corrosion resistance matter more than strength, 6061 is the practical choice.

Where 2A11 bar is used

• Fasteners: bolts, screws and medium-strength rivets
• Hydraulics and pneumatics: fittings, unions, valve bodies and pistons
• Aerospace and defence: secondary structural fittings and brackets
• Machinery: shafts, pins, spacers, bushings and gear blanks
• Tooling: jigs, fixtures and light mould components
• Instruments and transport: housings, frames and machined parts

Related grades and products

How to order 2A11 bar from Metline

1. SpecifyAlloy 2A11, temper (T4, O or H112), shape and size, length or cut pieces, and quantity.
2. Confirm the standardGB/T 3191 for extruded bar, or a dual 2A11 / 2017A certification if your drawing allows it; add coarse grain ring and ultrasonic limits where required.
3. QuoteWe confirm availability, tolerance class, certification and delivery terms (EXW, FOB, CIF or DAP) for your destination port or site.
4. Process and inspectBar is cut to length, checked for diameter, straightness and surface, and tested to the order requirements.
5. Document and shipEach lot ships with an EN 10204 3.1 mill test certificate and packing list. Bars are bundled or cased in seaworthy wooden boxes with moisture protection; third-party inspection can be arranged on request.

2A11 aluminium (aluminum) bar: frequently asked questions