7075-T6511
Solution heat-treated, stretched about 1 – 3 % to relieve quench stress and straighten, then aged. The "1" means minor straightening is allowed after stretching. This is the normal temper for angle that will be machined.
High-strength extruded angle
7075 Aluminium Angle: Grades, Sizes and Design Guide
7075 aluminium angle is an extruded L-section in the strongest commonly available aluminium alloy, used where a light frame, stiffener or bracket has to carry loads that would overstress 6061. It is normally supplied in the T6511 temper to ASTM B221 and AMS-QQ-A-200/11, with a typical yield strength of about 500 MPa. This guide explains properties, standard sizes, weights, joining limits and when 7075 is (and is not) the right angle to specify.
- Alloy
- 7075 (Al-Zn-Mg-Cu)
- Tempers
- T6, T6511, T73511, O
- Legs
- 1/2 – 6 in (12 – 150 mm)
- Standards
- ASTM B221 · AMS-QQ-A-200/11
What is 7075 aluminium angle?
An angle is the simplest structural shape after the flat bar: two legs at 90°, either equal or unequal, extruded in one piece. Made in 7075, it offers roughly 1.8 times the yield strength of 6061-T6 angle at almost the same weight, which is why it appears in aircraft stringers and clips, racing chassis, drone frames and highly loaded machine brackets.
7075 is a 7xxx alloy strengthened by zinc and magnesium, with copper and chromium added for strength and resistance to stress-corrosion cracking. Extruding it is slower and more demanding than extruding 6xxx alloys: the billet must be pushed at low speed to avoid surface tearing, and the sections must be solution heat-treated and quenched separately before being stretched and aged. That is the main reason 7075 angle costs several times more than 6061 or 6063 angle and is offered in a narrower range of sizes.
The trade-off is clear. 7075 gives the highest strength-to-weight ratio of any widely stocked aluminium angle, excellent fatigue strength and very good machinability. It gives up weldability (fusion welding is not recommended), formability in the hard temper and some corrosion resistance compared with 6xxx alloys. Designers therefore use it for bolted or riveted structures where every gram matters.
7075 chemical composition (wt %)
Registered Aluminum Association limits, identical to EN 573-3 (EN AW-7075). The mill certificate reports the actual analysis of each lot.
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | — | 0.40 | Impurity; kept low for toughness |
| Iron (Fe) | — | 0.50 | Impurity; forms coarse constituents that cut fatigue life |
| Copper (Cu) | 1.2 | 2.0 | Adds strength and improves stress-corrosion behaviour |
| Manganese (Mn) | — | 0.30 | Minor grain control |
| Magnesium (Mg) | 2.1 | 2.9 | Combines with Zn to form the MgZn2 strengthening phase |
| Chromium (Cr) | 0.18 | 0.28 | Controls recrystallisation and stress-corrosion cracking |
| Zinc (Zn) | 5.1 | 6.1 | Main alloying element |
| Titanium (Ti) | — | 0.20 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder | About 87 – 91 % |
Mechanical properties and tempers of 7075 angle
For extruded angle, the specification gives minimum values by the thickness of the leg. Typical values are what the material usually achieves; design to the specified minimum shown on the certificate.
| Temper / basis | Tensile strength | Yield strength (0.2 %) | Elongation |
|---|---|---|---|
| O (annealed), typical | 230 MPa / 33 ksi | 105 MPa / 15 ksi | 16 – 17 % |
| T6 / T6511, typical | 572 MPa / 83 ksi | 503 MPa / 73 ksi | 11 % |
| T6511, minimum, legs under 6.3 mm (0.249 in) | 538 MPa / 78 ksi | 483 MPa / 70 ksi | 7 % |
| T6511, minimum, legs 6.3 – 12.6 mm | 558 MPa / 81 ksi | 503 MPa / 73 ksi | 7 % |
| T73511, typical | 505 MPa / 73 ksi | 435 MPa / 63 ksi | 13 % |
Minimum values summarised from ASTM B221 and AMS-QQ-A-200/11 for extruded shapes; thicker bands and T73511 minimums are listed on the order specification and certificate.
Physical properties (T6)
- Density
- 2.81 g/cm³ (0.101 lb/in³)
- Modulus of elasticity
- 71.7 GPa (10,400 ksi)
- Shear strength, typical
- 331 MPa (48 ksi)
- Fatigue strength (5×10⁸ cycles)
- 159 MPa (23 ksi)
- Brinell hardness
- 150 HB
- Thermal conductivity
- 130 W/m·K
- Electrical conductivity
- 33 % IACS
- Melting range
- 477 – 635 °C
Which temper to order? The options differ in stress relief and corrosion behaviour more than in shape:
7075-T6
Peak-aged but not stress-relieved by stretching. Seen on small sections and older drawings; it can move more during machining than T6511.
7075-T73511
Over-aged for much better resistance to stress-corrosion cracking and exfoliation, at a cost of about 10 – 15 % in strength. Specified for aircraft fittings in humid or salt environments.
7075-T76511
An intermediate over-aged temper with better exfoliation resistance than T6 and less strength loss than T73. Used for some aircraft stringers.
7075-O
Annealed and soft for forming. Parts are bent in O and then heat-treated to T6, which needs controlled furnaces and quenching.
Not available: H tempers
7075 is heat-treatable, so it is never supplied in strain-hardened H tempers. Drawings that show them should be queried.
Standards and international equivalents
| System | Designation | Extruded shape standard |
|---|---|---|
| Aluminum Association / ASTM | 7075 | ASTM B221 (ASME SB-221) |
| US aerospace | 7075-T6, T6511, T73511 | AMS-QQ-A-200/11, AMS 2772 (heat treatment) |
| UNS | A97075 | — |
| European | EN AW-7075 / EN AW-AlZn5.5MgCu | EN 755-1, -2, -9 (shapes) |
| German Werkstoff | 3.4365 | DIN EN 755 |
| Japan | A7075S | JIS H4100 |
| ISO | AlZn5.5MgCu | ISO 6362 |
| China | 7075 | GB/T 6892, GB/T 3191 |
EN 755-9 sets dimensional tolerances for extruded profiles, and ASTM B221 refers to ANSI H35.2 for the same purpose. Aerospace buyers normally also call for ultrasonic inspection, a conductivity check to confirm temper, and full lot traceability.
7075 angle sizes and weights
Typical supply range
- Leg length
- 1/2 – 6 in (about 12 – 150 mm), equal and unequal legs
- Leg thickness
- 1/16 – 3/4 in (about 1.6 – 19 mm)
- Corners
- Sharp-corner (machined-look) or radiused root and toe for structural use
- Length
- Random mill lengths or cut lengths of about 1 – 6 m
- Finish
- Mill finish, anodised, or primed for aerospace assembly
- Processing
- Saw-cut to length, drilled, CNC machined to drawing
Metric sizes follow EN 755-9 tolerances. Share a section drawing for non-standard legs or corner radii.
The cross-sectional area of an equal or unequal angle is t × (a + b − t), where a and b are the leg lengths and t is the thickness. Multiply by the density of 7075 (2.81 g/cm³) to get weight per metre. The table ignores corner radii, which add a few per cent on radiused sections. For any size, use the angle weight calculator.
| Angle (a × b × t) | Area (in²) | kg per metre | lb per foot |
|---|---|---|---|
| 1/2 × 1/2 × 1/8 in | 0.109 | 0.198 | 0.133 |
| 3/4 × 3/4 × 1/8 in | 0.172 | 0.312 | 0.209 |
| 1 × 1 × 1/8 in | 0.234 | 0.425 | 0.285 |
| 1 × 1 × 1/4 in | 0.438 | 0.793 | 0.533 |
| 1-1/4 × 1-1/4 × 3/16 in | 0.434 | 0.786 | 0.528 |
| 1-1/2 × 1-1/2 × 1/8 in | 0.359 | 0.652 | 0.438 |
| 1-1/2 × 1-1/2 × 1/4 in | 0.688 | 1.246 | 0.837 |
| 2 × 2 × 1/8 in | 0.484 | 0.878 | 0.590 |
| 2 × 2 × 1/4 in | 0.938 | 1.700 | 1.142 |
| 2 × 2 × 3/8 in | 1.359 | 2.464 | 1.656 |
| 2-1/2 × 2-1/2 × 1/4 in | 1.188 | 2.153 | 1.446 |
| 3 × 3 × 1/4 in | 1.438 | 2.606 | 1.751 |
| 3 × 3 × 3/8 in | 2.109 | 3.824 | 2.569 |
| 4 × 4 × 3/8 in | 2.859 | 5.184 | 3.483 |
| 4 × 4 × 1/2 in | 3.750 | 6.798 | 4.567 |
| 6 × 6 × 1/2 in | 5.750 | 10.424 | 7.004 |
Machining, cutting, joining and finishing
Cutting
Band saws and cold saws with fine-pitch carbide or bi-metal blades give clean ends. Use lubricant and keep feed steady; 7075 chips cleanly and does not smear like softer alloys.
Machining
Excellent in T6511: short chips, bright finish and good dimensional stability. Use sharp, high-rake carbide or PCD tools and generous coolant. Machine heavy cuts symmetrically to limit distortion on long legs.
Joining
Fusion welding (MIG/TIG) is not recommended: 7075 is prone to hot cracking and the weld zone loses most of its strength. Join with bolts, rivets (7050 or 2024 rivets are common) or structural adhesives. Friction-stir welding is possible in controlled production.
Bending
T6511 angle tolerates only gentle bends with large radii. For tight bends, form in O or freshly quenched W condition and age afterwards. Never bend after anodising; the hard coating cracks.
Corrosion protection
Lower general corrosion resistance than 6xxx alloys, and T6 can be sensitive to stress-corrosion cracking under sustained tension in the short-transverse direction. Anodise, chromate-free conversion coat and prime, or specify T73511 for humid or marine service.
Anodising
Takes clear and hard anodic coatings, although colour is slightly greyer and less uniform than on 6061. Sulphuric acid anodising with sealing is the usual finish for aerospace detail parts.
Where 7075 angle is used
- Aircraft structures: stringers, frame clips, floor-beam stiffeners and cargo-system brackets supplied to AMS-QQ-A-200/11
- Defence equipment: lightweight frames for shelters, weapon mounts and vehicle fittings that are bolted rather than welded
- Motorsport and performance vehicles: chassis brackets, roll-cage gussets and suspension mounts where fatigue matters
- Drones and robotics: arms, frames and stiffeners where stiffness per gram is critical
- Machinery: highly loaded brackets, guide rails and fixture frames that must not deflect
- Sports equipment: climbing and rescue hardware frames, archery and cycling components
7075 angle compared with 6061, 2024 and steel
| Property | 7075-T6511 | 6061-T6 | 2024-T3511 | Mild steel (S275) |
|---|---|---|---|---|
| Typical yield strength | 503 MPa | 276 MPa | 345 MPa | 275 MPa |
| Density (g/cm³) | 2.81 | 2.70 | 2.78 | 7.85 |
| Yield strength / density | 179 | 102 | 124 | 35 |
| Weldability | Not recommended | Good | Poor | Excellent |
| Corrosion resistance | Fair | Good | Fair–poor | Poor unless coated |
| Relative cost per kg | High | Low | High | Lowest |
A steel angle will always be cheaper per kilogram, but a 7075 angle can carry the same load at around one-third of the weight. Compared with 6061 angle, 7075 lets you drop one or two section sizes, which often recovers part of the material cost. 2024 angle has better fatigue-crack growth resistance and is preferred for some tension-dominated aircraft parts, while 7050 angle keeps its toughness in thicker legs.
How to order 7075 angle
- Define the sectionLeg lengths, thickness, corner type (sharp or radiused), and whether legs are equal or unequal. A drawing avoids misunderstandings.
- State temper and standardFor example 7075-T6511 to AMS-QQ-A-200/11 or ASTM B221, or EN AW-7075 T6 to EN 755-2.
- Add length and processingMill lengths or cut lengths, end squareness, holes or machining, and surface finish.
- Specify inspectionMill test certificate to EN 10204 3.1 as standard; ultrasonic, conductivity or third-party inspection when required.
- Agree deliveryEXW, FOB, CIF or DAP terms, with export packing in wooden crates that protect the legs from bending.
References and standards
- ASTM B221 – Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles, and Tubes
- SAE AMS-QQ-A-200/11 – Aluminum Alloy 7075, Bar, Rod, Shapes, Tube and Wire, Extruded
- EN 755-2 – Extruded rod/bar, tube and profiles: mechanical properties
- EN 573-3 – Chemical composition and form of wrought products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM International – Properties of Wrought Aluminum and Aluminum Alloys: 7075
7075 aluminium (aluminum) angle: frequently asked questions
Can 7075 aluminium angle be welded?
Conventional MIG or TIG welding is not recommended. 7075 is susceptible to hot cracking, and the weld zone drops to a fraction of the parent strength. Use bolts, rivets or adhesive bonding, or choose 6061 or 6082 angle if the design must be welded.
What is the difference between 7075-T6 and 7075-T6511 angle?
Both are peak-aged with the same strength. T6511 has been stretched after quenching to relieve residual stress, with minor straightening allowed afterwards, so it distorts less when machined. Most extruded 7075 angle is supplied as T6511.
How do I calculate the weight of a 7075 angle?
Area = t × (a + b − t), using leg lengths a and b and thickness t. Multiply the area in mm² by 2.81 and divide by 1,000 to get kg per metre. A 2 × 2 × 1/4 in angle weighs about 1.70 kg/m (1.14 lb/ft) before allowing for corner radii.
Is 7075 angle stronger than steel angle?
A 7075-T6511 angle has a higher yield strength (about 500 MPa) than common structural steel (about 275 – 355 MPa) at roughly one-third of the density. Steel is stiffer, so for deflection-limited designs the aluminium section usually needs to be deeper.
Does 7075 angle corrode?
It resists normal atmospheres but is less corrosion-resistant than 6061, and the T6 temper can suffer stress-corrosion cracking under sustained tension. Anodise or prime the parts, isolate them from steel and carbon fibre, and specify T73511 for humid or salt-laden service.
Can you cut 7075 angle to length and machine it?
Yes. Metline supplies 7075 angle in mill lengths or cut to size, with drilling and CNC machining to drawing on request, and ships worldwide with an EN 10204 3.1 certificate.
Need 7075 angle?
Send the section size, temper, standard, lengths and destination. We reply with availability, certification and a delivered price.
