Aluminum 707.0-T7
Temper
AA 707.0 · UNS A07070 · also ZG42A
T7 = solution heat treated and overaged (stabilized)
Choose for dimensional stability at temperature and reduced stress-corrosion sensitivity; permanent-mold T7 also gives the alloy's highest strength combination.
Values for the T7 condition
Other 707.0 tempers and conditions
707.0 is listed in 4 conditions; see the grade overview at 707.0.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Pick for machining stock or when parts will subsequently be aged; strength is still climbing at room temperature. | 140 | 205 | 3 | 60 HB | 32 % IACS |
Cooled from hot working and naturally aged | The signature temper of this alloy: full room-temperature aging (weeks) gives near-T5 strength with no furnace cycle and minimal distortion. | 165 | 228 | 3 | 68 HB | 33 % IACS |
T5Default Cooled from hot working and artificially aged | Standard stocked condition: a short low-temperature age accelerates and stabilizes precipitation for peak strength without solution treating. | 193 | 240 | 2 | 75 HB | 35 % IACS |
T7This page Solution heat treated and overaged (stabilized) | Choose for dimensional stability at temperature and reduced stress-corrosion sensitivity; permanent-mold T7 also gives the alloy's highest strength combination. | 220 | 275 | 2 | 85 HB | 37 % IACS |
What is 707.0-T7?
707.0-T7 is 707.0 in the T7 temper — choose for dimensional stability at temperature and reduced stress-corrosion sensitivity; permanent-mold T7 also gives the alloy's highest strength combination. 707.0-T7 has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 59% of aluminum grades. Elongation at break is 2% and the elastic modulus is 70.5 GPa (10.2 Msi). 707.0-T7 has a density of 2.9 g/cm³ (0.105 lb/in³), heavier than 98% of aluminum grades. It melts at 599°C (1,110 °F). T5 is the default condition FabDigit quotes; T7 is available on request or by drawing note.
Advantages
- Easy to machine — 80/100, better than 92% of aluminum grades
- Polishes to a fine finish — 70/100, better than 87% of aluminum grades
- High service temperature — 175°C (347 °F), better than 83% of aluminum grades
Limitations
- Limited ductility — 2%, worse than 87% of aluminum grades
- Limited formability — 10/100, worse than 80% of aluminum grades
707.0-T7 properties
Typical room-temperature values for 707.0-T7; 11 are specific to this condition. Other listed values are 707.0 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
707.0-T7 has a density of 2.9 g/cm³ (0.105 lb/in³), heavier than 98% of aluminum grades. It melts at 599°C (1,110 °F).
Mechanical13
707.0-T7 has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 59% of aluminum grades. Elongation at break is 2% and the elastic modulus is 70.5 GPa (10.2 Msi).
Thermal6
707.0-T7 is rated for continuous service to 175°C (347 °F). It conducts heat at 138 W/m·K (79.7 BTU/hr·ft·°F), worse than 55% of aluminum grades. Thermal expansion is 23.6 µm/m·K (13.1 µin/in·°F).
Electrical3
707.0-T7 conducts electricity at 37 % IACS, better than 58% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 71% of aluminum grades.
Sustainability4
Producing a kilogram of 707.0-T7 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 40%.
Manufacturability8
707.0-T7's machinability is very good (80/100, better than 92% of aluminum grades); weldability fair (40/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 707.0-T7
Is 707.0 easy to machine?
One of the best-machining cast aluminums — free-cutting chips, good surface finish with polished-flute carbide and moderate feeds; machine after natural aging has stabilized to avoid dimensional drift.
Can 707.0 be welded?
Fusion welding is possible with 5356 filler but the Al-Zn-Mg composition is hot-crack sensitive and the HAZ re-ages unevenly; re-age or T7 stabilize after welding, and avoid welds in SCC-critical areas.
Can 707.0 be formed, bent or molded?
Poor foundry alloy: low fluidity, long freezing range and high hot-tear tendency — needs generous fillets, directional solidification, chills and good gating; sand and permanent mold only, not for die casting.
What surface finishes work on 707.0?
Takes clear and dyed anodizing better than Si-bearing cast alloys; chromate/anodize plus paint recommended for humid or marine service to limit SCC and pitting.
707.0 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 | ≤ 0.2 | 0.1 |
| Fe | ≤ 0.8 | 0.4 |
| Cu | ≤ 0.2 | 0.1 |
| Mn | 0.4 – 0.6 | 0.5 |
| Mg | 1.8 – 2.4 | 2.1 |
| Cr | 0.2 – 0.4 | 0.3 |
| Zn | 4 – 4.5 | 4.25 |
| Tigrain refiner, max | ≤ 0.25 | 0.15 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
707.0-T7 — frequently asked
What is 707.0-T7 used for?
707.0-T7 is typically used for structural castings, ordnance parts and machinery housings. In short: self-aging cast aluminum; stronger than 705.0; free-cutting cast alloy.
What is the yield strength of 707.0-T7?
707.0-T7 has a typical yield strength of 220 MPa (31.9 ksi) and a tensile strength of 275 MPa (39.9 ksi) — stronger than 59% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is 707.0-T7 easy to machine?
Yes — machinability is rated very good (80/100, better than 92% of aluminum grades). One of the best-machining cast aluminums — free-cutting chips, good surface finish with polished-flute carbide and moderate feeds; machine after natural aging has stabilized to avoid dimensional drift.
Can 707.0-T7 be welded?
With care — weldability is rated fair (40/100). Fusion welding is possible with 5356 filler but the Al-Zn-Mg composition is hot-crack sensitive and the HAZ re-ages unevenly; re-age or T7 stabilize after welding, and avoid welds in SCC-critical areas.
What surface finishes work on 707.0-T7?
Takes clear and dyed anodizing better than Si-bearing cast alloys; chromate/anodize plus paint recommended for humid or marine service to limit SCC and pitting.
Can 707.0-T7 be formed, bent or molded?
Poor foundry alloy: low fluidity, long freezing range and high hot-tear tendency — needs generous fillets, directional solidification, chills and good gating; sand and permanent mold only, not for die casting.
What is the maximum service temperature of 707.0-T7?
707.0-T7 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 707.0-T5 and 707.0-F?
T5 is the default condition — standard stocked condition: a short low-temperature age accelerates and stabilizes precipitation for peak strength without solution treating. F: pick for machining stock or when parts will subsequently be aged; strength is still climbing at room temperature. Yield strength is 193 MPa in T5 versus 140 MPa in F.
Sources
- Registration Record of Aluminum Association Alloy Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot (Pink Sheets) — The Aluminum Association (2018)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- ASTM B108/B108M — Aluminum-Alloy Permanent Mold Castings — ASTM International (2019)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.