7075-T6
Solution treated at about 465 – 480 °C, quenched and aged near 120 °C. Maximum strength; acceptable for thin, simple forgings without sustained short-transverse stress.
Highest-strength common forging alloy
7075 Aluminium Forgings
7075 aluminium forgings deliver the highest strength of the common forging alloys, with grain flow that follows the part for better fatigue life and toughness than machined plate. They are used for aircraft fittings, landing-gear and wing components, defence hardware and high-performance motorsport parts. Metline supplies 7075 die forgings, hand forgings, rolled rings and discs in T6, T73 and T7352, certified to AMS, ASTM and EN, to customers worldwide.
- Alloy
- 7075 (Al-Zn-Mg-Cu)
- Tempers
- T6, T73, T7352, T74
- Forms
- Die and hand forgings, rings, discs
- Standards
- AMS 4126 · AMS 4141 · ASTM B247
What are 7075 aluminium forgings?
7075 contains about 5.6 % zinc, 2.5 % magnesium and 1.6 % copper. In the peak-aged T6 condition it reaches tensile strengths above 500 MPa, so a 7075 forging can replace a steel part at roughly a third of the weight in many moderately loaded applications.
7075 is harder to forge than 6061 or 2014. Its forging window is narrow (roughly 380 – 440 °C), it needs higher press loads and it is sensitive to cracking if the metal cools on the dies. In exchange, forging gives what 7075 most needs: a refined, unrecrystallised grain structure aligned with the part, which improves fatigue strength and greatly reduces the short-transverse weakness that makes thick 7075 plate vulnerable to stress-corrosion cracking.
The temper decision matters more for 7075 forgings than for almost any other product. T6 gives maximum strength but poor resistance to stress-corrosion cracking (SCC) when residual or assembly stresses act across the grain. That is why most structural aircraft forgings in 7075 are ordered in the over-aged T73 family, and why newer designs often move to 7050 or 7175 in T74. Our job is to make sure the temper on the order matches how the part will actually be loaded and exposed.
7075 chemical composition (wt %)
Aluminum Association limits, used by AMS, ASTM B247 and EN 573-3 (EN AW-7075). The high-purity variant 7175 has tighter Fe and Si limits for better toughness in forgings.
| Element | Minimum | Maximum | What it does |
|---|---|---|---|
| Zinc (Zn) | 5.1 | 6.1 | Main strengthener with Mg |
| Magnesium (Mg) | 2.1 | 2.9 | Forms MgZn2 precipitates |
| Copper (Cu) | 1.2 | 2.0 | Adds strength and SCC resistance |
| Chromium (Cr) | 0.18 | 0.28 | Restricts recrystallisation during forging and heat treatment |
| Silicon (Si) | — | 0.40 | Impurity |
| Iron (Fe) | — | 0.50 | Impurity |
| Manganese (Mn) | — | 0.30 | |
| Titanium (Ti) | — | 0.20 | Grain refiner |
| Others, each / total | — | 0.05 / 0.15 | |
| Aluminium (Al) | Remainder |
Mechanical properties of 7075 forgings
Typical values below are for wrought 7075 in each temper and represent the longitudinal grain-flow direction. Forging specifications set lower guaranteed minimums that depend on section thickness and test direction; the second group of rows shows commonly cited ASTM B247 longitudinal minimums for thinner die forgings.
| Condition | Tensile strength | Yield strength (0.2 %) | Elongation |
|---|---|---|---|
| 7075-T6, typical | 572 MPa / 83 ksi | 503 MPa / 73 ksi | 11 % |
| 7075-T73, typical | 505 MPa / 73 ksi | 435 MPa / 63 ksi | 13 % |
| 7075-T6 die forging, minimum (up to about 25 mm) | 517 MPa / 75 ksi | 441 MPa / 64 ksi | 7 % |
| 7075-T73 die forging, minimum (up to about 75 mm) | 455 MPa / 66 ksi | 386 MPa / 56 ksi | 7 % |
Minimums for hand forgings and rolled rings, for thicker sections and for transverse directions are lower. The applicable values are stated in the order specification and on the certificate.
Physical properties
- Density
- 2.81 g/cm³
- Modulus of elasticity
- 71.7 GPa
- Electrical conductivity
- 33 % IACS (T6); about 40 % IACS or higher (T73)
- Thermal conductivity
- 130 W/m·K (T6); about 155 W/m·K (T73)
- Coefficient of thermal expansion
- 23.6 µm/m·°C
- Melting range
- About 477 – 635 °C
T6, T73, T7352 or T74?
7075-T652
T6 with 1 – 5 % cold compression before ageing to relieve quench stress; for hand forgings to be heavily machined.
7075-T73
Two-step over-ageing (lower then higher temperature). About 10 – 15 % less strength than T6 but high resistance to SCC and exfoliation. Standard for aircraft die forgings.
7075-T7352
T73 with compressive stress relief. The usual temper for 7075 hand forgings and rolled rings that will be machined deeply.
7075-T74
An intermediate over-aged temper with better strength than T73 and good SCC resistance; also used for 7175 and 7050 forgings.
Conductivity check
Over-aged tempers are verified by eddy-current conductivity together with hardness, because over-ageing raises conductivity measurably.
Specifications and equivalents for 7075 forgings
| Standard / system | Designation or scope |
|---|---|
| SAE AMS 4126 | 7075-T6 die forgings, hand forgings and rolled rings |
| SAE AMS 4141 | 7075-T73 die forgings |
| AMS-QQ-A-367 / AMS-A-22771 | General aluminium forging requirements and heat treatment of forgings |
| ASTM B247 / B247M | Die forgings, hand forgings and rolled ring forgings for general and aerospace use |
| EN 586-1/-2/-3 | Forgings, EN AW-7075 (AlZn5.5MgCu) |
| UNS / Werkstoff | A97075 / 3.4365 |
| JIS | A7075 forgings to JIS H4140 |
Aircraft forgings are usually bought to the airframer's own material specification, which references these documents. Tell us the full specification and revision; we will confirm compliance before quoting rather than assume equivalence.
7075 forging forms and sizes
Closed-die forgings
Near-net fittings, brackets, links and housings with grain flow following the contour.
Hand forgings and blocks
Rectangular and stepped blocks in T7352 for machining complex fittings.
Rolled rings
Seamless rings for engine mounts, gear blanks and frames.
Forged discs
Upset discs for wheels, flanges and covers.
Forged bar and shafts
Large-section bar and stepped shafts beyond the range of extruded bar.
Machined parts
Rough- or finish-machined forgings to drawing, with inspection reports.
Typical supply envelope
- Die forgings
- Plan areas from small fittings up to large structural parts, subject to die and press availability
- Hand forgings
- Sections from about 50 mm to several hundred millimetres
- Rings and discs
- Diameters from about 150 mm up to large rings and discs
- Condition
- As-forged, rough-machined or finish-machined
Feasible sizes depend on shape, temper and specification. Send a drawing for a forging proposal.
Testing and inspection of 7075 forgings
Typical inspection plan
- Chemistry
- Heat analysis of forging stock
- Tensile tests
- Longitudinal, long-transverse and short-transverse as required, from prolongations or sacrificial parts
- Hardness and conductivity
- On every forging, to verify heat treatment and over-aged temper
- Ultrasonic
- To AMS-STD-2154 class AA, A or B as ordered
- Grain flow and microstructure
- Macro-etch and micro-examination on first articles
- SCC testing
- Alternate-immersion stress-corrosion testing where the specification requires it
- Certification
- EN 10204 3.1; 3.2 with third-party witness on request
Machining, joining and protection
Machining
Excellent machinability with sharp carbide tools; stress-relieved T652 and T7352 forgings move least during deep pocketing.
Joining
Not fusion weldable. Use fasteners, interference fits or adhesive bonding.
Surface treatment
Sulphuric or chromic acid anodising, hard anodising for wear surfaces, conversion coating and primer for aircraft parts.
Shot peening
Commonly applied to fatigue-critical forgings to introduce compressive surface stress.
Where 7075 forgings are used
- Aircraft structure: wing and fuselage fittings, frames, landing-gear components, actuator housings
- Helicopters: rotor hub parts and transmission housings (to the OEM's specification)
- Defence: weapon mounts, missile bodies, armoured-vehicle components
- Motorsport and cycling: wheels, uprights, cranks and suspension parts
- Industrial: high-speed machine parts, robotic arms and lightweight tooling
7075 forgings compared with 7050, 2014 and 6061
| Property | 7075-T73 | 7050-T74 | 2014-T6 | 6061-T6 |
|---|---|---|---|---|
| Strength | High | Higher in thick sections | High | Medium |
| Quench sensitivity (thick sections) | High | Low | Moderate | Moderate |
| SCC resistance | Very good | Very good | Low – moderate | Very good |
| Forgeability | Fair | Fair | Good | Excellent |
| Relative cost | High | Very high | Medium | Low |
For forgings thicker than about 75 – 100 mm, 7050 keeps its strength through the section better than 7075 because it is less quench-sensitive. 2014 is a cheaper high-strength option for less critical parts, and 6061 is the right choice when corrosion resistance and weldability matter more than strength. See also the 6061 vs 7075 comparison.
How to order 7075 forgings
- SpecifyDrawing, alloy and temper (e.g. 7075-T7352), material specification and revision, test directions, UT class, SCC or conductivity requirements and quantity.
- ReviewWe propose the forging route, machining allowance, test locations and inspection plan.
- First articleFirst-article inspection with dimensional, mechanical and grain-flow results for new parts.
- DocumentEN 10204 3.1 certificate with chemistry, heat-treatment records and test results, plus UT and dimensional reports.
- ShipCorrosion-protected, crated for export and shipped EXW, FOB, CIF or DAP.
References and standards
- SAE AMS 4126 – Aluminum Alloy Forgings, 7075-T6
- ASTM B247 – Aluminum and Aluminum-Alloy Die Forgings, Hand Forgings, and Rolled Ring Forgings
- EN 586-2 – Aluminium and aluminium alloys: forgings, mechanical properties
- The Aluminum Association – International Alloy Designations and Chemical Composition Limits
- ASM Handbook, Vol. 2 – Properties of Wrought Aluminum and Aluminum Alloys: 7075
7075 aluminium (aluminum) forgings: frequently asked questions
Should I order 7075 forgings in T6 or T73?
Choose T73 (or T7352 for hand forgings and rings) whenever the part sees sustained tensile stress across the grain or a corrosive environment. T6 gives about 10 – 15 % more strength but is prone to stress-corrosion cracking in thick sections.
What is the difference between T73 and T7352?
Both are over-aged for SCC resistance. T7352 forgings are also cold-compressed after quenching to relieve residual stress, so they stay stable during machining.
Why are 7075 forgings stronger than parts machined from plate?
Peak strength is similar, but the forging's grain flow follows the part, which improves fatigue life, toughness and short-transverse properties. That often allows a lighter design.
Can 7075 forgings be welded?
No, not by conventional fusion welding. Design joints for fasteners or bonding.
When should I use 7050 instead of 7075 forgings?
For thick sections, usually above about 75 – 100 mm, where 7050's lower quench sensitivity gives higher strength and toughness at the centre of the part.
Can you supply 7075 forgings with ultrasonic inspection?
Yes. Ultrasonic inspection to AMS-STD-2154 class AA, A or B can be specified, with reports supplied alongside the mill certificate.
Need 7075 forgings?
Send the drawing, temper and specification. We will propose a forging route, inspection plan and delivered price.
