Aluminum 712 · temper
Aluminum 712-T1
Properties of the T1 condition, compared with the other 712 tempers.
Self-aging Al-Zn-Mg sand casting alloy 712.0 in the as-cast, naturally aged T1 condition — develops near-T5 strength without solution treatment, with good machinability and dimensional stability.
What is 712-T1?
712-T1 is 712 in the T1 temper — self-aging Al-Zn-Mg sand casting alloy 712.0 in the as-cast, naturally aged T1 condition — develops near-T5 strength without solution treatment, with good machinability and dimensional stability. 712-T1 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 57% of aluminum grades. Elongation at break is 4% and the elastic modulus is 71 GPa (10.3 Msi). 712-T1 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 570°C (1,058 °F).
712-T1 properties
Typical room-temperature values for 712-T1 — 26 properties are specific to this condition; the rest are grade-level values shared by every 712 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
712-T1 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 570°C (1,058 °F).
Mechanical10
712-T1 has a yield strength of 170 MPa (24.7 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 57% of aluminum grades. Elongation at break is 4% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
712-T1 is rated for continuous service to 150°C (302 °F). It conducts heat at 159 W/m·K (91.9 BTU/hr·ft·°F), better than 74% of aluminum grades. Thermal expansion is 23.6 µm/m·K (13.1 µin/in·°F).
Electrical3
712-T1 conducts electricity at 35 % IACS, better than 52% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (50/100), worse than 56% of aluminum grades.
Sustainability4
Producing a kilogram of 712-T1 takes about 195 MJ of energy and emits 12 kg of CO₂ — less than 86% of aluminum grades. Typical recycled content is 50%.
Manufacturability6
712-T1's machinability is very good (70/100, better than 72% of aluminum grades); weldability good (55/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 712 tempers and conditions
712 is also supplied in 3 other conditions. The full side-by-side table is on the 712 overview.
- T5Choose when the natural-aging waiting period is unacceptable or dimensional stability before machining is required; a short low-temperature age gives essentially the naturally aged property level.175 MPa yield · 78 HB
- FStandard supply condition: strength develops by self-aging over ~2–4 weeks at room temperature, no solution treatment or quench needed.172 MPa yield · 75 HB
- T1Self-aging Al-Zn-Mg sand casting alloy 712.0 in the as-cast, naturally aged T1 condition — develops near-T5 strength without solution treatment, with good machinability and dimensional stability.170 MPa yield · 75 HB
Working with 712-T1
Is 712 easy to machine?
Machines well with sharp carbide or PCD tooling, high speed and light feed; free-flowing chips, good surface finish, and it holds size well because no quench stresses are present.
Can 712 be welded?
Fair-to-good with GTAW/GMAW using 5356 or 5183 filler; the Zn–Mg matrix re-ages naturally so strength recovers near the weld, but keep heat input low to limit hot cracking and porosity.
Can 712 be formed, bent or molded?
Sand casting is the practical route — fluidity is only moderate and the alloy is hot-tear sensitive, so use generous fillets, directional solidification and chills; avoid permanent-mould/die casting.
What surface finishes work on 712?
Anodizes well (clear or hard coat) and takes chromate/conversion coatings and paint; polish to a moderate lustre only, since sand-cast porosity limits mirror finishes.
712 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 | ≤ 0.3 | — |
| Fe | ≤ 0.5 | — |
| Cu | ≤ 0.25 | — |
| Mn | ≤ 0.1 | — |
| Mg | 0.5 – 0.65 | 0.58 |
| Cr | 0.4 – 0.6 | 0.5 |
| Zn | 5 – 6.5 | 5.8 |
| Tigrain refiner | 0.15 – 0.25 | 0.2 |
| Others (each)0.20 total max | ≤ 0.05 | — |
| Al | balance | — |
712-T1 — frequently asked
What is 712-T1 used for?
712-T1 is typically used for decorative castings, hardware and light brackets. In short: cast Al-Zn-Mg.
What is the yield strength of 712-T1?
712-T1 has a typical yield strength of 170 MPa (24.7 ksi) and a tensile strength of 240 MPa (34.8 ksi) — weaker than 57% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is 712-T1 easy to machine?
Yes — machinability is rated very good (70/100, better than 72% of aluminum grades). Machines well with sharp carbide or PCD tooling, high speed and light feed; free-flowing chips, good surface finish, and it holds size well because no quench stresses are present.
Can 712-T1 be welded?
Yes — weldability is rated good (55/100). Fair-to-good with GTAW/GMAW using 5356 or 5183 filler; the Zn–Mg matrix re-ages naturally so strength recovers near the weld, but keep heat input low to limit hot cracking and porosity.
What surface finishes work on 712-T1?
Anodizes well (clear or hard coat) and takes chromate/conversion coatings and paint; polish to a moderate lustre only, since sand-cast porosity limits mirror finishes.
Can 712-T1 be formed, bent or molded?
Sand casting is the practical route — fluidity is only moderate and the alloy is hot-tear sensitive, so use generous fillets, directional solidification and chills; avoid permanent-mould/die casting.
What is the maximum service temperature of 712-T1?
712-T1 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 712-T1?
Yes — 712-T1 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- 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 (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- ASM Handbook Vol.15 — Casting — ASM International (2008)
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.