7075-O
Fully annealed. The softest condition, used for cold heading, coiling and forming. The finished part is then solution treated and aged to T6 or T73 under AMS 2770 or the customer process.
Aerospace · High-strength wire
7075 Aerospace Aluminium Wire
7075 aluminium wire is the high-strength Al-Zn-Mg-Cu wire used for aerospace fasteners, pins, cold-headed parts and small machined components where steel would be too heavy. Metline supplies 7075 wire in the annealed (O), as-fabricated (F), T6 and over-aged T73/T7351 tempers to AMS 4122, AMS 4124 and ASTM B211, in coils or straight lengths, to aerospace buyers worldwide.
- Alloy
- 7075 (Al-Zn-Mg-Cu)
- Tempers
- O, F, T6, T73, T7351
- Diameter
- About 1 – 12 mm wire; larger as rod
- Specs
- AMS 4122 · AMS 4124 · ASTM B211
What 7075 wire is and why aircraft use it
7075 is the classic high-strength aerospace alloy. In wire form it gives a tensile strength above 500 MPa in the T6 temper at roughly one third of the density of steel, which is why it is drawn into wire for rivets, pins, screws, cold-headed blanks and spring clips in airframes, missiles and satellites.
Wire is produced by extruding or rolling 7075 rod, then cold drawing it through successive dies with intermediate anneals. Because 7075 work-hardens quickly and is less ductile than 2xxx or 6xxx alloys, it is usually drawn in the annealed condition and heat-treated to T6 or T73 after the final draw or after the part has been cold headed. The result is a fine-grained, accurately sized wire with a clean surface suitable for heading, thread rolling and anodising.
The key design decision is temper. T6 gives the highest strength but is susceptible to stress-corrosion cracking (SCC) when loaded in the short-transverse direction or in sustained tension. The over-aged T73 family gives up about 10 – 15 % of strength in exchange for very high SCC resistance, so it is the usual choice for fasteners and parts that stay loaded for decades. For rivets, many designs have moved to 7050-T73 because it can be driven without the rivet cracking, while 7075 remains common for pins, screws and machined wire parts.
7075 chemical composition (wt %)
7075 wire follows the registered Aluminum Association limits, which AMS 4122, AMS 4124, ASTM B211 and EN 573-3 (EN AW-7075, AlZn5.5MgCu) all use. The mill test certificate reports the actual cast analysis.
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | — | 0.40 | Impurity; kept low for toughness |
| Iron (Fe) | — | 0.50 | Impurity; forms coarse particles that start fatigue cracks |
| Copper (Cu) | 1.2 | 2.0 | Raises strength and improves stress-corrosion resistance |
| Manganese (Mn) | — | 0.30 | Minor grain control |
| Magnesium (Mg) | 2.1 | 2.9 | Forms MgZn2 precipitates with zinc |
| Chromium (Cr) | 0.18 | 0.28 | Controls recrystallisation and grain shape |
| Zinc (Zn) | 5.1 | 6.1 | Main strengthening element |
| Titanium (Ti) | — | 0.20 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 87 – 91 % |
7175 is a higher-purity version of the same chemistry (Si ≤ 0.15, Fe ≤ 0.20) used where better toughness and fatigue life are needed, mainly in forgings and extrusions.
Mechanical properties of 7075 wire by temper
Typical values show what the wire usually achieves. Specified minimums are what AMS 4122, AMS 4124 and ASTM B211 guarantee, and they vary slightly with diameter, so always design to the minimum on the certificate.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation | Shear strength | Hardness |
|---|---|---|---|---|---|
| O, typical | 228 MPa / 33 ksi | 103 MPa / 15 ksi | 16 – 17 % | 152 MPa | 60 HB |
| O, specified maximum | 276 MPa / 40 ksi | 145 MPa / 21 ksi | ≥ 10 % | — | — |
| T6, typical | 572 MPa / 83 ksi | 503 MPa / 73 ksi | 11 % | 331 MPa | 150 HB |
| T6, specified minimum (ASTM B211) | 531 MPa / 77 ksi | 455 MPa / 66 ksi | 7 % | — | — |
| T73 / T7351, typical | 505 MPa / 73 ksi | 435 MPa / 63 ksi | 13 % | 303 MPa | 135 HB |
| T73, specified minimum (ASTM B211) | 469 MPa / 68 ksi | 386 MPa / 56 ksi | 10 % | — | — |
Typical values from ASM and Aluminum Association data. Minimums summarised for cold-finished wire and rod; check the size band in the standard you order to.
Physical properties (T6)
- Density
- 2.81 g/cm³ (0.101 lb/in³)
- Modulus of elasticity
- 71.7 GPa (10,400 ksi)
- Thermal conductivity
- 130 W/m·K (T6); about 155 W/m·K (T73)
- Electrical conductivity
- About 33 % IACS (T6); about 40 % IACS (T73)
- Coefficient of thermal expansion
- 23.4 µm/m·°C (20 – 100 °C)
- Melting range
- 477 – 635 °C
Which 7075 wire temper should you order?
7075-F
As fabricated, with no guaranteed properties. Bought as stock for further drawing or forging. AMS 4186 covers F-temper bar, rod and wire, with O available on request.
7075-T6
Solution heat-treated and artificially aged. Maximum strength for pins, shafts and machined wire parts. Avoid it for parts under sustained tensile load in humid or salt environments.
7075-T73
Solution treated and over-aged in two steps. Strength drops to about 470 MPa minimum, but stress-corrosion resistance is excellent. Standard for fasteners and long-life loaded parts.
7075-T7351
T73 with a controlled stretch to relieve quench stresses; applies mainly to larger rod and bar. AMS 4124 covers rolled or cold-finished T7351 bar, rod and wire up to 6 in diameter.
Electrical conductivity check
Over-aged tempers are verified by eddy-current conductivity as well as hardness, because conductivity confirms that the over-ageing step was done correctly.
7075 wire specifications and international equivalents
Most aerospace drawings call up an AMS specification. Commercial and defence orders often use ASTM. Tell us the specification and revision on your drawing and we will supply and certify to it.
| Specification | Scope |
|---|---|
| SAE AMS 4122 | 7075-T6 / T651 bars, rods and wire, rolled, drawn or cold-finished |
| SAE AMS 4124 | 7075-T7351 bars, rods and wire, rolled or cold-finished, up to 6.000 in |
| SAE AMS 4186 | 7075 bars, rods and wire in the F temper (O on request) |
| ASTM B211 / B211M | Aluminium and aluminium-alloy rolled or cold-finished bar, rod and wire |
| ASTM B316 / B316M | Aluminium and aluminium-alloy rivet and cold-heading wire and rod |
| EN 573-3 / EN 754 | EN AW-7075 [AlZn5.5MgCu] chemistry and cold-drawn rod, bar and wire |
| System | Designation |
|---|---|
| Aluminum Association / ASTM | 7075 |
| UNS | A97075 |
| European (EN) | EN AW-7075 / AlZn5.5MgCu |
| German Werkstoff | 3.4365 |
| ISO | AlZn5.5MgCu |
| Japan (JIS) | A7075 |
| China (GB) | 7075 (close to 7A09) |
7075 wire sizes and weights
Supply range
- Diameter
- Wire from about 1 mm up to 12 mm; larger diameters supplied as drawn or extruded rod
- Inch sizes
- Fractional and rivet sizes such as 1/16, 3/32, 1/8, 5/32, 3/16, 1/4 and 5/16 in
- Form
- Coils, spools or straight cut lengths
- Surface
- Bright drawn; lubricant-free or coated for cold heading on request
- Processing
- Cut-to-length, straightening and centreless grinding of rod on request
Weight per metre is calculated from the 7075 density of 2.81 g/cm³:
| Diameter (mm) | kg per metre | metres per kg | Inch equivalent |
|---|---|---|---|
| 1 | 0.0022 | 453 | 0.039 |
| 1.6 | 0.0056 | 177 | 0.063 |
| 2 | 0.0088 | 113 | 0.079 |
| 2.5 | 0.0138 | 72 | 0.098 |
| 3 | 0.0199 | 50 | 0.118 |
| 3.2 | 0.0226 | 44 | 0.126 |
| 4 | 0.0353 | 28 | 0.157 |
| 4.8 | 0.0508 | 20 | 0.189 |
| 5 | 0.0552 | 18 | 0.197 |
| 6 | 0.0795 | 13 | 0.236 |
| 6.35 | 0.0890 | 11 | 0.250 |
| 8 | 0.1412 | 7 | 0.315 |
| 9.5 | 0.1992 | 5 | 0.374 |
| 10 | 0.2207 | 5 | 0.394 |
| 12 | 0.3178 | 3 | 0.472 |
Tolerances, surface and inspection
Diameter tolerances follow the tables in ASTM B211 and ANSI H35.2 unless the order states tighter limits. Rivet and cold-heading wire to ASTM B316 has closer diameter tolerances and stricter surface requirements, because seams, laps or die scratches open up into cracks when the head is upset.
Typical inspection plan
- Dimensions
- Diameter and ovality checked along the coil or on every bundle
- Surface
- Visual inspection for seams, scratches and pick-up; eddy-current testing on request
- Mechanical
- Tensile test per lot; shear and upset (heading) tests for rivet wire
- Over-aged tempers
- Electrical conductivity and hardness to confirm T73 condition
- Certification
- EN 10204 3.1 mill test certificate with chemistry, properties and lot number
Cold heading, machining and finishing
Cold heading
Head in the O or freshly quenched (W) condition, then age. Heading T6 wire risks cracking. Freshly quenched wire must be headed within a short window or held refrigerated to delay natural ageing.
Machining
In T6 and T73 tempers 7075 machines very well: short chips, good finish and accurate threads. Use sharp carbide or HSS tools and plenty of coolant.
Thread rolling
Rolled threads add fatigue life. They are normally rolled after heat treatment for best fatigue performance.
Welding
Not suitable for arc welding. Fusion welds crack and lose strength. Join by fastening, swaging or adhesive bonding.
Anodising
Takes sulphuric and chromic acid anodising; aerospace fasteners are often anodised and primed. Hard anodising adds wear resistance on pins.
Corrosion protection
Always protect 7075 parts in service: anodise, apply chemical conversion coating and primer, and wet-install fasteners with sealant to avoid galvanic attack.
Where 7075 aerospace wire is used
- Fasteners: screws, pins, lockbolt collars and special rivets made from cold-headed wire
- Pins and shafts: hinge pins, clevis pins and small shafts in control systems
- Spacecraft and satellites: lightweight standoffs, inserts and machined fittings
- Missiles and UAVs: small structural pins, fin hinge pins and fasteners
- Interiors and equipment: seat and galley hardware where strength per gram matters
- Sporting and precision goods: spokes, archery parts and high-strength clips
A typical example is a hinge pin for an access panel: drawn 7075 wire is cut, machined and heat-treated to T73, anodised and greased. It carries the hinge load for the life of the aircraft without the stress-corrosion risk that a T6 pin would bring.
7075 wire compared with 2024, 2117 and 7050
| Property | 7075-T73 | 7050-T73 | 2024-T4 | 2117-T4 |
|---|---|---|---|---|
| Typical tensile strength | 505 MPa | About 500 MPa | 470 MPa | 295 MPa |
| Typical shear strength | 303 MPa | About 300 MPa | 283 MPa | 196 MPa |
| Stress-corrosion resistance | Very good | Very good | Fair | Good |
| Rivet driving | Not usually driven | Driven as received (E rivets) | Ice-box rivets (W) | Driven as received (AD) |
| Typical use | Pins, screws, special fasteners | High-strength rivets | High-strength rivets | General rivets |
If your part is a solid rivet, compare 7075 with 7050 and 2117 first. For screws, pins and machined parts, 7075 in T73 is usually the best balance. Our 7075 rivet wire guide and 7050 rivet wire guide cover the rivet case in detail.
How to order 7075 aerospace wire
- SpecifyAlloy and temper, diameter, coil or length, surface condition, quantity and the governing specification with its revision letter (AMS 4122, AMS 4124, ASTM B211 or B316). Add any customer or prime-contractor material specification that sits on top of the AMS.
- ConfirmWe confirm the specification can be met, the tolerance class, any extra tests (ultrasonic class, conductivity, fracture toughness, grain flow) and the delivery terms (EXW, FOB, CIF or DAP).
- InspectMaterial is checked for dimensions, surface condition and marking; tests named on the order are carried out or arranged with an independent laboratory.
- DocumentEach lot ships with a mill test certificate to EN 10204 3.1 giving chemistry, mechanical results and heat-treatment lot, traceable to the cast number.
- Pack and shipExport packing in sealed, moisture-protected wooden cases or on pallets, shipped by sea or air to your port or door.
References and standards
- SAE AMS 4122 – Bars, Rods and Wire, 7075-T6 / T651
- SAE AMS 4124 – Bars, Rods and Wire, 7075-T7351
- SAE AMS 4186 – Bars, Rods and Wire, 7075-F
- ASTM B211 – Rolled or Cold-Finished Bar, Rod and Wire
- ASTM B316 – Rivet and Cold-Heading Wire and Rods
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
7075 aerospace aluminium (aluminum) wire: FAQ
What is the difference between 7075-T6 and 7075-T73 wire?
Both are solution heat-treated. T6 is aged for peak strength (about 572 MPa typical tensile). T73 is over-aged in two steps, which lowers tensile strength to about 505 MPa but gives much better resistance to stress-corrosion cracking. Choose T73 for parts under sustained load.
Can 7075 wire be cold headed?
Yes, but heading is done in the annealed (O) or freshly quenched condition, and the parts are aged afterwards. Heading wire that is already in T6 usually cracks the head.
Which specification covers 7075-T6 wire?
SAE AMS 4122 covers 7075-T6 and T651 bars, rods and wire. ASTM B211 is the general commercial standard, and ASTM B316 covers rivet and cold-heading wire.
Is 7075 wire weldable?
Not by arc welding. 7075 is prone to hot cracking, and the weld zone loses most of its strength. Use mechanical fastening or adhesive bonding.
Why are 7075 rivets less common than 7050 rivets?
7075 rivets are hard to drive without cracking in the aged condition. 7050-T73 rivets can be driven as received and still offer high shear strength, so they replaced 7075 in many airframe uses.
Do you supply 7075 wire outside India?
Yes. Metline supplies 7075 wire worldwide from Mumbai, with EN 10204 3.1 certificates, export packing and sea or air shipment.
Need 7075 wire for aerospace parts?
Send diameter, temper, specification and quantity. We will confirm availability, certification and a delivered price.
