7150-T77511
Solution heat-treated, stretched, straightened and aged by the T77 three-step cycle. Covered by AMS 4345 for extrusions 2.000 in (50.8 mm) and under in nominal diameter or least thickness.
Aerospace · Stringer extrusions
7150 Aerospace Aluminium Extrusions
7150 extrusions in the T77511 and T61511 tempers are high-strength, high-purity aluminium sections used for upper wing stringers, floor beams and other compression-loaded aircraft members. Metline supplies 7150 profiles and bar to SAE AMS 4345 and AMS 4307, with full test certification, to aerospace manufacturers worldwide.
- Alloy
- 7150 (Al-Zn-Mg-Cu-Zr)
- Tempers
- T77511, T61511
- Size
- Up to 50.8 mm (AMS 4345)
- Specs
- AMS 4345 · AMS 4307
What 7150 extrusions are used for
An upper wing is a stiffened panel: a skin with stringers running span-wise to stop it buckling under compression. Stringers are usually extruded, and when the skin is 7150 plate the stringers are often 7150 extrusions, so the panel has matched strength, corrosion behaviour and thermal expansion.
7150 is a derivative of 7050 with a little more zinc and magnesium and lower iron and silicon. Zirconium controls grain structure and keeps extrusions unrecrystallised through the section, which supports high longitudinal strength and good toughness. In extrusions the same tempers as plate are used, with the extra "1" for straightening: T61511 (stretched, near-peak aged) and T77511 (stretched and aged by the three-step T77 process).
Beyond wing stringers, 7150 sections appear in fuselage floor beams, seat-track supports, keel beams and frames where compressive and bending loads dominate. Where an extruded part must also resist high stress corrosion, T77511 is the normal choice.
7150 chemical composition (wt %)
Registered limits for 7150 (UNS A97150). AMS 4345 describes the alloy by its nominal chemistry, 6.4 Zn - 2.4 Mg - 2.2 Cu - 0.12 Zr.
| Element | Minimum | Maximum | Role in the alloy |
|---|---|---|---|
| Silicon (Si) | — | 0.12 | Kept very low for toughness |
| Iron (Fe) | — | 0.15 | Kept very low; fewer coarse particles |
| Copper (Cu) | 1.9 | 2.5 | Strength and SCC resistance |
| Manganese (Mn) | — | 0.10 | Minor |
| Magnesium (Mg) | 2.0 | 2.7 | Forms MgZn2 precipitates |
| Chromium (Cr) | — | 0.04 | Kept low; zirconium does grain control |
| Zinc (Zn) | 5.9 | 6.9 | Main strengthening element |
| Titanium (Ti) | — | 0.06 | Grain refiner |
| Zirconium (Zr) | 0.08 | 0.15 | Prevents recrystallisation; lowers quench sensitivity |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder |
Zinc in 7150 is 5.9 – 6.9 % and titanium at most 0.06 %. Data sheets that show higher zinc or titanium up to 0.25 % do not describe 7150.
Mechanical and physical properties
AMS 4345 and AMS 4307 specify minimum tensile properties by section thickness. MMPDS gives design values. The approximate typical values below compare 7150 with other aerospace extrusion alloys of similar thickness.
| Property (approx. typical) | 7150-T77511 | 7150-T61511 | 7050-T76511 | 7075-T73511 |
|---|---|---|---|---|
| Tensile strength | About 610 MPa | About 620 MPa | About 550 MPa | About 505 MPa |
| Yield strength (0.2 %) | About 570 MPa | About 580 MPa | About 490 MPa | About 435 MPa |
| Elongation | About 10 % | About 10 % | About 10 % | About 12 % |
| Exfoliation resistance | Good | Moderate | Good | Very good |
| SCC resistance | Good | Moderate | Moderate | Very good |
Physical properties
- Density
- About 2.82 g/cm³ (0.102 lb/in³)
- Modulus of elasticity
- About 71 – 72 GPa
- Electrical conductivity
- About 38 – 40 % IACS (T77511)
- Coefficient of thermal expansion
- About 23.5 µm/m·°C
7150 extrusion tempers
7150-T61511
Solution heat-treated, stretched, straightened and aged near peak strength. Ordered to AMS 4307 or an OEM specification. Use where the drawing calls for it.
Why T77 matters
T77 tempers use a three-step ageing cycle (age, brief high-temperature retrogression, re-age). The result keeps strength close to peak-aged T6 while giving exfoliation and stress-corrosion resistance close to the over-aged T76 condition.
Tempers to avoid confusing
AMS 4050 and AMS 4201 are 7050 plate specifications, not 7150 extrusion specifications. Check the alloy in the AMS title before ordering.
7150 extrusion shapes
| Shape | Typical use | Notes |
|---|---|---|
| J, Z, I and hat stringers | Upper wing and fuselage panels | Made to OEM die drawings |
| T and angle sections | Frames, clips and chords | Standard or custom dies |
| Floor and keel beam sections | Fuselage floor structure | Often machined after extrusion |
| Rectangular and round bar | Machined fittings | Up to the thickness limit of the specification |
7150 is a hard alloy to extrude: section complexity, minimum wall and length are limited by the extrusion press and stretcher, and are confirmed against your drawing. Weight per metre for a custom section is section area (mm²) × 2.82 / 1000 kg/m; for example a stringer with a 600 mm² cross-section weighs about 1.69 kg per metre.
| Section area (mm²) | kg per metre | kg per 6 m length |
|---|---|---|
| 200 | 0.56 | 3.4 |
| 300 | 0.85 | 5.1 |
| 400 | 1.13 | 6.8 |
| 600 | 1.69 | 10.2 |
| 800 | 2.26 | 13.5 |
| 1000 | 2.82 | 16.9 |
| 1500 | 4.23 | 25.4 |
| 2000 | 5.64 | 33.8 |
| 3000 | 8.46 | 50.8 |
Tolerances, testing and certification
Typical requirements
- Dimensional tolerances
- To ANSI H35.2 or the OEM drawing
- Tensile
- Longitudinal tests per lot; transverse tests on wider sections where required
- Corrosion
- Exfoliation (EXCO) and SCC lot acceptance per specification
- Conductivity
- Eddy-current conductivity on each lot
- Ultrasonic
- To AMS-STD-2154 on thicker sections when ordered
- Certification
- EN 10204 3.1 certificate with chemistry, properties and lot traceability
Machining, joining and protection
Machining
Machines cleanly. Stretch stress relief keeps long stringers straight when flanges are trimmed or pockets machined.
Forming
Limited cold forming. Joggles and contour bends are made in the freshly quenched condition or by age forming.
Joining
Riveted or bolted to skins and frames. Not fusion-welded.
Protection
Anodise or conversion coat and prime; seal faying surfaces and wet-install fasteners.
7150 extrusions compared with alternatives
Choose 7150-T77511 when the part is compression-critical and a 7150 or 7055 skin is used. Choose 7050-T76511 or T74511 where toughness and thicker sections matter more. Choose 7075-T73511 where maximum stress-corrosion resistance is required and lower strength is acceptable. For thick-walled fittings in an SCC-sensitive location, 7149-T73511 or 7175-T73511 are further options.
- Strength: 7055 > 7150 > 7050 > 7175 ≈ 7075 (T73)
- SCC resistance: 7075-T73 ≈ 7175-T73 ≈ 7149-T73 > 7050-T74 > 7150-T77
- Toughness: 7050 and 7175 lead; 7150 is good; 7075 is lowest
How to order 7150 extrusions
- SpecifyAlloy and temper, section drawing or die number, length, quantity and the governing specification with its revision letter (AMS 4345 or AMS 4307, plus any OEM specification). 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 4345 – Extrusions, 6.4Zn - 2.4Mg - 2.2Cu - 0.12Zr (7150-T77511)
- SAE AMS 4307 – Extrusions, 7150-T61511
- ANSI H35.2 – Dimensional Tolerances for Aluminum Mill Products
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits (Teal Sheets)
- MMPDS – Metallic Materials Properties Development and Standardization (successor to MIL-HDBK-5)
7150 aerospace aluminium (aluminum) extrusions: FAQ
What is 7150-T77511 used for?
Mainly upper wing stringers and other compression-loaded fuselage members such as floor and keel beams, often paired with 7150 or 7055 upper wing skins.
Which specification covers 7150-T77511 extrusions?
SAE AMS 4345, for extrusions 2.000 in (50.8 mm) and under in nominal diameter or least thickness. OEM material specifications often apply as well.
What does the T77511 temper mean?
Solution heat-treated, stress-relieved by stretching, straightened, and aged using the T77 three-step process that gives high strength with improved corrosion resistance.
Is 7150 stronger than 7075?
Yes. In comparable extruded sections 7150-T77511 has noticeably higher tensile and yield strength than 7075-T73511, though 7075-T73 has higher stress-corrosion resistance.
Can 7150 extrusions be welded?
No. They are joined by riveting or bolting.
Do you supply 7150 sections to customer dies?
Yes, subject to confirming that the section can be extruded and tested to the specification. We supply worldwide with full certification.
Need 7150 extrusions?
Send the section, temper, length and specification. We will confirm feasibility, testing and a delivered price.
