7075-T6
Solution heat-treated and aged to peak strength. Normal for small cold-finished and extruded bars. Highest strength, but residual quench stress and the highest SCC sensitivity.
High-strength aerospace grade
7075 Aluminium Flat Bar
7075 aluminium flat bar is a rectangular bar in the zinc-magnesium-copper alloy that gives the highest strength of any common aluminium grade, close to many structural steels at about one third of the weight. It is used for highly stressed machined parts, tooling and aerospace fittings, where weldability and corrosion resistance matter less than strength. Metline supplies 7075 flat bar in T6, T651, T73 and T7351, extruded, rolled or saw-cut from plate, to customers worldwide.
- Alloy
- 7075 (Al-Zn-Mg-Cu)
- Tempers
- T6, T651, T73, T7351, O
- Typical UTS
- 572 MPa (T6)
- Standards
- ASTM B211/B221 · AMS 4122/4124
What is 7075 aluminium flat bar?
7075 is a 7xxx-series alloy in which about 5.6 % zinc and 2.5 % magnesium form fine MgZn2 precipitates during ageing. The result, in T6 temper, is a typical tensile strength of about 570 MPa: nearly twice that of 6061-T6, and higher than mild steel.
Developed in the early 1940s for aircraft structures, 7075 is still the reference high-strength alloy for wing and fuselage fittings, but most flat bar today goes into machined parts outside aerospace: mould and die components, jigs and fixtures, robotic arms, bicycle and motorsport parts, firearm components and climbing equipment. A flat bar is a practical starting shape for these, because it reduces the amount of material to be machined away compared with plate.
Flat bar in 7075 reaches the customer by three routes. Smaller sections are extruded (ASTM B221, AMS 4154) or rolled and cold finished (ASTM B211, AMS 4122/4124). Wide or thick flats are often saw-cut from 7075-T651 plate, which gives the same stretched, stress-relieved condition and is certified to the plate standard. Tell us which route your specification requires, because the certificate and tolerances differ.
7075 chemical composition (wt %)
Registered Aluminum Association limits, shared by ASTM, AMS and EN 573-3 (EN AW-7075). The certificate for each lot gives the actual analysis.
| Element | Minimum | Maximum | What it does |
|---|---|---|---|
| Zinc (Zn) | 5.1 | 6.1 | Main strengthening element with magnesium |
| Magnesium (Mg) | 2.1 | 2.9 | Forms MgZn2 precipitates |
| Copper (Cu) | 1.2 | 2.0 | Adds strength and improves resistance to stress-corrosion cracking |
| Chromium (Cr) | 0.18 | 0.28 | Controls grain structure, improves SCC resistance |
| Silicon (Si) | — | 0.40 | Impurity |
| Iron (Fe) | — | 0.50 | Impurity; lower in premium grades for toughness |
| Manganese (Mn) | — | 0.30 | Impurity |
| Titanium (Ti) | — | 0.20 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 87 – 91 % |
Mechanical properties of 7075 flat bar by temper
Typical values come from published handbook data and describe normal behaviour. Specified minimums depend on the product form (extruded, cold finished or plate-cut), the thickness and the test direction, and are the values to design with.
| Temper | Tensile strength | Yield strength (0.2 %) | Elongation | Brinell hardness |
|---|---|---|---|---|
| O, typical | 228 MPa / 33 ksi | 103 MPa / 15 ksi | 17 % | 60 HB |
| T6 / T651, typical | 572 MPa / 83 ksi | 503 MPa / 73 ksi | 11 % | 150 HB |
| T73 / T7351, typical | 505 MPa / 73 ksi | 435 MPa / 63 ksi | 13 % | — |
| T6 extruded bar, EN 755-2 minimum (≤ 25 mm) | 540 MPa | 480 MPa | 7 % | — |
| T6 extruded bar, EN 755-2 minimum (25 – 100 mm) | 560 MPa | 500 MPa | 7 % | — |
ASTM B211, B221 and the AMS specifications have their own minimum tables by size; the applicable values appear on the mill certificate for your lot.
Physical properties (T6)
- Density
- 2.81 g/cm³ (0.102 lb/in³), about 4 % heavier than 6061
- Modulus of elasticity
- 71.7 GPa (10,400 ksi)
- Shear strength
- 331 MPa (48 ksi)
- Fatigue strength (5×10⁸ cycles)
- 159 MPa (23 ksi)
- Thermal conductivity
- 130 W/m·K (T6); about 155 W/m·K (T73)
- Electrical conductivity
- 33 % IACS (T6); about 40 % IACS (T73)
- Coefficient of thermal expansion
- 23.6 µm/m·°C (20 – 100 °C)
- Melting range
- About 477 – 635 °C
T6, T651 or T7351: which 7075 temper?
7075-T651
T6 plus stretching to relieve quench stress. Stays straight and flat when machined. The usual choice for plate-cut flat bar and larger rolled bar.
7075-T6511
The extruded-bar version of T651: stretched, with minor straightening allowed afterwards.
7075-T73 / T7351
Over-aged to trade about 10 – 15 % of strength for much better resistance to stress-corrosion cracking and exfoliation. Specified for aerospace fittings loaded in the short-transverse direction. Conductivity is used to verify the temper.
7075-T76 / T7651
Intermediate over-age that improves exfoliation resistance with a smaller strength loss than T73. More common in plate and extrusions than bar.
7075-O
Annealed for forming. Rarely bought as flat bar except where it will be formed and then heat-treated.
7075 standards and international equivalents
| System | Designation | Bar specifications |
|---|---|---|
| ASTM | 7075 | ASTM B211 (cold-finished bar), ASTM B221 (extruded bar), ASTM B209 for plate-cut bar |
| SAE AMS | 7075-T6 / T651 / T7351 | AMS 4122, AMS 4123, AMS 4124 (rolled or cold-finished bar); AMS 4154 (extrusions); AMS-QQ-A-225/9 |
| UNS | A97075 | — |
| European (EN) | EN AW-7075 / EN AW-AlZn5.5MgCu | EN 754-2 (drawn), EN 755-2 (extruded), EN 573-3 |
| German Werkstoff | 3.4365 | DIN EN 754 / 755 |
| ISO | AlZn5.5MgCu | ISO 6362 |
| Japan (JIS) | A7075 | JIS H4040 |
| China (GB) | 7075 | GB/T 3191 |
UK aerospace and defence drawings sometimes call for the British L-series or DTD specifications, and some European programmes use the 7075 variant 7175 for forgings. If your drawing quotes a superseded specification, send it to us and we will propose the current equivalent for your approval rather than assume equivalence.
7075 flat bar sizes and weights
Supply range
- Thickness
- About 3 – 100 mm; thicker sections cut from plate
- Width
- About 10 – 300 mm; wider strips saw-cut from T651 plate
- Length
- Mill lengths up to about 3.6 – 6 m, or cut to length
- Imperial sizes
- 1/8 – 4 in thick, 1/2 – 12 in wide
- Edges
- Extruded/rolled edges, or saw-cut and deburred edges on plate-cut bar
- Processing
- Saw cutting, fly-cut or precision-milled faces on request
Because 7075 is denser than 6xxx alloys, its weight is width (mm) × thickness (mm) × 0.00281 kg per metre. Use the flat bar weight calculator for other sizes.
| Width × thickness (mm) | kg per metre | kg per 6 m length |
|---|---|---|
| 20 × 3 | 0.169 | 1.01 |
| 25 × 5 | 0.351 | 2.11 |
| 30 × 6 | 0.506 | 3.03 |
| 40 × 5 | 0.562 | 3.37 |
| 40 × 10 | 1.124 | 6.74 |
| 50 × 6 | 0.843 | 5.06 |
| 50 × 10 | 1.405 | 8.43 |
| 60 × 8 | 1.349 | 8.09 |
| 75 × 10 | 2.107 | 12.64 |
| 80 × 12 | 2.698 | 16.19 |
| 100 × 10 | 2.810 | 16.86 |
| 100 × 20 | 5.620 | 33.72 |
| 120 × 15 | 5.058 | 30.35 |
| 150 × 20 | 8.430 | 50.58 |
| 200 × 25 | 14.050 | 84.30 |
Tolerances, inspection and certification
Quality plan
- Tolerances
- ANSI H35.2 tables for ASTM and AMS orders; EN 755-5 (extruded) or EN 754-5 (drawn) rectangular bar for EN orders; plate-cut bar to agreed saw tolerances, typically ±0.5 – 1 mm
- Temper verification
- Hardness and electrical conductivity checks; conductivity is the standard way to confirm T73 / T7351
- Ultrasonic testing
- To AMS-STD-2154 or ASTM B594 class on request for aerospace and critical parts
- Mechanical tests
- Tensile results per lot, with test direction stated
- Certification
- EN 10204 3.1 mill test certificate; 3.2 with third-party witness on request
For aerospace work, the order should state the AMS specification and revision, the temper, grain direction requirements and any ultrasonic class. Leaving out the revision is a common reason for certificates being rejected at goods-in inspection.
Machining, joining, finishing and heat
Machining
Excellent. Hard tempers give short chips and fine finishes, and parts hold tolerance well. Use sharp carbide, high spindle speeds and good chip evacuation. T651 limits distortion when large volumes are removed.
Welding
Not recommended for fusion welding: hot cracking and severe strength loss. Join with fasteners, adhesives or friction stir welding. If a weldable 7xxx alloy is required, 7020 or 7005 are the usual alternatives.
Forming
Very limited in T6. Form in O or freshly quenched W condition, then heat-treat.
Anodising
Takes hard and decorative anodising, with a slightly yellow-grey tint compared with 6063. Hard anodise is common on wear surfaces.
Corrosion protection
Lower corrosion resistance than 5xxx and 6xxx. Anodise, chromate or paint parts in outdoor or marine service, and use T73 where SCC is a risk.
Temperature
Loses strength progressively above about 120 °C as the alloy over-ages. Not for sustained elevated-temperature service; consider 2xxx grades there.
Where 7075 flat bar is used
- Aerospace: wing and fuselage fittings, brackets, seat tracks, ground support equipment
- Tooling: mould plates, die components, jigs and fixtures where low weight eases handling
- Automation and robotics: arms, end-effectors and high-speed moving parts
- Defence: weapon components and equipment mounts
- Sport and leisure: climbing hardware, bicycle components, archery and motorsport parts
- Consumer electronics: machined housings and frames that need high stiffness-to-weight
7075 flat bar compared with 6061, 2024 and 7050
| Property | 7075-T651 | 6061-T651 | 2024-T351 | 7050-T7451 |
|---|---|---|---|---|
| Typical tensile strength | 572 MPa | 310 MPa | 469 MPa | About 525 MPa |
| Typical yield strength | 503 MPa | 276 MPa | 324 MPa | About 470 MPa |
| Fatigue performance | Good | Moderate | Very good | Very good |
| SCC resistance | Low (T6), good (T73) | Very good | Moderate | Good |
| Weldability | Poor | Good | Poor | Poor |
| Relative cost | High | Low | High | Very high |
Choose 6061 when strength needs are moderate and welding or cost matter. Choose 2024 for fatigue-critical tension parts. Choose 7050 for thick aerospace sections where through-thickness toughness and SCC resistance are specified. The 6061 vs 7075 and 2024 vs 7075 articles compare these grades in more depth.
How to order 7075 flat bar
- SpecifyTemper (T6, T651, T7351), width × thickness, length, quantity and the specification with revision (e.g. AMS 4124, ASTM B211, EN 755-2).
- QuoteWe confirm the supply route (extruded, cold finished or plate-cut), tolerance, testing and delivery terms (EXW, FOB, CIF or DAP).
- ProcessBars are sawn to length, deburred, marked with alloy, temper and heat number, and protected against handling damage.
- DocumentEN 10204 3.1 mill certificate with chemistry and mechanical results; ultrasonic reports where ordered.
- ShipPacked in sealed, moisture-protected wooden cases for sea or air freight.
References and standards
- ASTM B211 – Aluminum and Aluminum-Alloy Rolled or Cold-Finished Bar, Rod, and Wire
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- SAE AMS 4124 – 7075-T7351 rolled or cold-finished bars, rods and wire
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM International – Properties of Wrought Aluminum and Aluminum Alloys: 7075
7075 aluminium (aluminum) flat bar: frequently asked questions
How strong is 7075-T6 flat bar?
Typical tensile strength is about 572 MPa (83 ksi) and yield about 503 MPa (73 ksi). Guaranteed minimums are lower and depend on size and standard; for extruded bar up to 25 mm EN 755-2 requires 540 MPa tensile and 480 MPa yield.
What is the difference between 7075-T651 and 7075-T7351?
Both are stretched to relieve stress. T651 is aged to peak strength; T7351 is over-aged, giving roughly 10 – 15 % lower strength but far better resistance to stress-corrosion cracking. Aerospace fittings with short-transverse loads normally use T7351.
Can 7075 flat bar be welded?
Not by conventional MIG or TIG; the welds crack and lose most of their strength. Use mechanical fastening, bonding or friction stir welding, or switch to a weldable alloy such as 6061 or 7020.
Is plate-cut 7075 flat bar as good as extruded bar?
Mechanically, yes: strips sawn from 7075-T651 plate keep the plate properties and are stress-relieved. The differences are the certificate standard (plate rather than bar) and saw-cut edges that may need machining.
How much does 7075 flat bar weigh?
Width × thickness (mm) × 0.00281 gives kg per metre. A 50 × 10 mm bar weighs about 1.41 kg/m and a 100 × 20 mm bar about 5.62 kg/m.
Do you supply 7075 flat bar to AMS specifications?
Yes. We supply to AMS, ASTM and EN specifications with mill certificates, and ship worldwide on EXW, FOB, CIF or DAP terms.
Need 7075 flat bar?
Send temper, size, specification and quantity. We will confirm the supply route, certification and a delivered price.
