Aluminum 7129
AA 7129 · UNS A97129
7129 (A97129, AlZn4.5Mg1.5Cu(A)) is a medium-to-high-strength Al-Zn-Mg-Cu wrought alloy supplied in O, T4, T5, T6, T62 and the overaged T73/T76 tempers.
Reference datasheet — 7129 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the T6 condition
7129 tempers and conditions
7129 is supplied in 7 conditions, soft to hard. T6 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest condition for severe forming or re-solution-treating; not a service temper. | 110 | 230 | 17 | 60 HB | 38 % IACS |
Solution heat treated and naturally aged | Use when parts must be formed or bent after heat treatment and then allowed to age or artificially aged later. | 210 | 330 | 18 | 95 HB | 29 % IACS |
Solution heat treated and overaged for stress-corrosion resistance | Choose for humid, salty or sustained-tension service where stress-corrosion cracking must be avoided, accepting ~10-15 % lower strength. | 290 | 345 | 13 | 105 HB | 39 % IACS |
Overaged for exfoliation-corrosion resistance | Intermediate overage: better exfoliation/SCC resistance than T6 with less strength loss than T73. | 315 | 370 | 12 | 112 HB | 37 % IACS |
Cooled from hot working and artificially aged | Standard low-cost temper for press-quenched automotive bumper and structural extrusions where full T6 solution treatment is not needed. | 325 | 370 | 11 | 112 HB | 33 % IACS |
T6, heat treated by the user | Specified when a formed or annealed part is re-heat-treated to T6-level properties by the fabricator. | 345 | 395 | 10 | 118 HB | 32 % IACS |
T6Default Solution heat treated and artificially aged | Default stocked condition: peak strength for structural extrusions and machined parts in protected or coated service. | 350 | 400 | 11 | 120 HB | 32 % IACS |
What is 7129?
7129 (A97129, AlZn4.5Mg1.5Cu(A)) is a medium-to-high-strength Al-Zn-Mg-Cu wrought alloy supplied in O, T4, T5, T6, T62 and the overaged T73/T76 tempers. Default values are 350 MPa yield, 400 MPa tensile, 11 % elongation and 120 HB with machinability 62/100, and it is used for structural components that need strength with moderate formability. Copper limits fusion welding (weldability 30/100), corrosion resistance is 40/100 and maximum service temperature is 120 °C; T73/T76 improve stress-corrosion behaviour at reduced strength. 7204 or 7108A are the alternatives when welding is required. 7129 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 480°C (896 °F). 7129 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 83% of aluminum grades. Elongation at break is 11% and the elastic modulus is 70 GPa (10.2 Msi).
What is 7129 used for?
- Structural components
- Transport equipment brackets
- Bolted and riveted frame members
- Machined mounting blocks
- Hot-forged structural fittings
- Load-bearing extruded profiles
- Sporting goods tubing
Advantages
- High strength — 350 MPa (50.8 ksi), better than 83% of aluminum grades
- Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 76% of aluminum grades
Limitations
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
- Needs corrosion protection — 40/100, worse than 75% of aluminum grades
7129 properties
Typical room-temperature values for 7129-T6; bars are the position among aluminum grades.
Physical3
7129 has a density of 2.8 g/cm³ (0.101 lb/in³), heavier than 81% of aluminum grades. It melts at 480°C (896 °F).
Mechanical13
7129 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 83% of aluminum grades. Elongation at break is 11% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
7129 is rated for continuous service to 120°C (248 °F). It conducts heat at 155 W/m·K (89.6 BTU/hr·ft·°F), better than 71% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
7129 conducts electricity at 32 % IACS, worse than 63% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 75% of aluminum grades.
Sustainability4
Producing a kilogram of 7129 takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 25%.
Manufacturability7
7129's machinability is good (62/100, better than 55% of aluminum grades); weldability poor (30/100); formability fair (35/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. 7129 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 7129
Is 7129 easy to machine?
Machines freely in T5/T6 with sharp carbide tools, high speeds and flood coolant; chips are short and surface finish is good, keep tools honed to avoid built-up edge.
Can 7129 be welded?
Cu-bearing 7000 series — avoid fusion welding (hot cracking and severe HAZ/SCC loss); join by riveting, bolting, adhesive or FSW with qualified procedures.
Can 7129 be formed, bent or molded?
Extrudes and hot-forms well (typical 380-450 °C billet); cold bending should be done in O/T4 or with generous radii, as T6 bend limits are tight.
7129 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Si | ≤ 0.15 | |
| Fe | ≤ 0.3 | |
| Cu | 0.5 – 0.9 | 0.7 |
| Mn | ≤ 0.1 | |
| Mg | 1.3 – 2 | 1.6 |
| Cr | ≤ 0.1 | |
| Zn | 4.2 – 5.2 | 4.7 |
| Ti | ≤ 0.05 | |
| Others (each)each | ≤ 0.05 | |
| Others (total)total | ≤ 0.15 | |
| Al | balance |
What surface finishes work on 7129?
Takes clear/hard anodize and chromate or chrome-free conversion coatings well and paints readily; polish before anodizing since Zn-Cu content slightly dulls decorative anodic films.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum 7129 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A97129
How much does 7129 cost?
7129 is a premium-cost aluminum ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
7129 — frequently asked
What is 7129 used for?
7129 is typically used for structural components, transport equipment brackets, bolted and riveted frame members, machined mounting blocks, hot-forged structural fittings and load-bearing extruded profiles. In short: strength-formability balance; T73/T76 for SCC resistance; free-machining aged 7000 series.
What is the yield strength of 7129?
7129 has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 400 MPa (58 ksi) — stronger than 83% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 7129 easy to machine?
Reasonably — machinability is rated good (62/100, better than 55% of aluminum grades). Machines freely in T5/T6 with sharp carbide tools, high speeds and flood coolant; chips are short and surface finish is good, keep tools honed to avoid built-up edge.
Can 7129 be welded?
Not readily — weldability is rated poor (30/100). Cu-bearing 7000 series — avoid fusion welding (hot cracking and severe HAZ/SCC loss); join by riveting, bolting, adhesive or FSW with qualified procedures.
What surface finishes work on 7129?
Takes clear/hard anodize and chromate or chrome-free conversion coatings well and paints readily; polish before anodizing since Zn-Cu content slightly dulls decorative anodic films.
Can 7129 be formed, bent or molded?
Extrudes and hot-forms well (typical 380-450 °C billet); cold bending should be done in O/T4 or with generous radii, as T6 bend limits are tight.
What is the maximum service temperature of 7129?
7129 is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 7129-T6 and 7129-O?
T6 is the default condition — default stocked condition: peak strength for structural extrusions and machined parts in protected or coated service. O: softest condition for severe forming or re-solution-treating; not a service temper. Yield strength is 350 MPa in T6 versus 110 MPa in O.
How much does 7129 cost?
7129 is a premium-cost aluminum ($$$), cheaper than about 51% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials (aluminium alloys) — ASM International (2005)
- ASTM B221 — Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles and Tubes — ASTM International (2021)
- MMPDS-class typical property data for 7000-series extrusions — Battelle / FAA (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.