Aluminum AL4-T7
Temper
T7 = solution heat treated and overaged (stabilized)
Overaged for dimensional stability and service above ~150 °C, trading some strength for toughness and stability.
Values for the T7 condition
Other AL4 tempers and conditions
AL4 is listed in 6 conditions; see the grade overview at AL4.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | Cheapest condition for lightly loaded, dimensionally stable housings where strength is not critical. | 90 | 165 | 3 | 55 HB | 43 % IACS |
Solution heat treated and naturally aged | Choose when maximum ductility and impact toughness matter more than yield strength (e.g. crash-loaded brackets). | 110 | 205 | 8 | 60 HB | 37 % IACS |
Cooled from hot working and naturally aged | Simple low-cost ageing that raises strength and stabilises dimensions without a quench, so distortion is minimal. | 140 | 205 | 2 | 70 HB | 41 % IACS |
Cooled from hot working and artificially aged | Low-temperature ageing used mainly to relieve casting stresses and stabilise dimensions with a modest strength gain. | 140 | 180 | 2 | 60 HB | 43 % IACS |
T7This page Solution heat treated and overaged (stabilized) | Overaged for dimensional stability and service above ~150 °C, trading some strength for toughness and stability. | 160 | 220 | 5 | 70 HB | 40 % IACS |
T6Default Solution heat treated and artificially aged | Standard structural condition: best combination of strength, fatigue life and acceptable ductility for loaded castings. | 180 | 240 | 4 | 75 HB | 39 % IACS |
What is AL4-T7?
AL4-T7 is AL4 in the T7 temper — overaged for dimensional stability and service above ~150 °C, trading some strength for toughness and stability. AL4-T7 has a yield strength of 160 MPa (23.2 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 61% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72.4 GPa (10.5 Msi). AL4-T7 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 557°C (1,035 °F). T6 is the default condition FabDigit quotes; T7 is available on request or by drawing note.
Advantages
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
Limitations
- Hard to polish — 45/100, worse than 76% of aluminum grades
AL4-T7 properties
Typical room-temperature values for AL4-T7; 21 are specific to this condition. Other listed values are AL4 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
AL4-T7 has a density of 2.68 g/cm³ (0.0968 lb/in³), lighter than 72% of aluminum grades. It melts at 557°C (1,035 °F).
Mechanical13
AL4-T7 has a yield strength of 160 MPa (23.2 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 61% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72.4 GPa (10.5 Msi).
Thermal6
AL4-T7 is rated for continuous service to 200°C (392 °F). It conducts heat at 158 W/m·K (91.3 BTU/hr·ft·°F), better than 74% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
AL4-T7 conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 71% of aluminum grades.
Sustainability4
Producing a kilogram of AL4-T7 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 55%.
Manufacturability8
AL4-T7's machinability is good (56/100, worse than 55% of aluminum grades); weldability very good (80/100); formability not recommended (14/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with AL4-T7
Is AL4 easy to machine?
Machines cleanly in T6 with PCD or coated-carbide tools and high speeds; free silicon abrades HSS quickly, so use flood coolant and sharp positive-rake geometry.
Can AL4 be welded?
Readily TIG/MIG welded with ER4043 (or ER4047) filler; re-solution treat and age locally welded structural parts, and preheat/clean thoroughly to avoid porosity.
Can AL4 be formed, bent or molded?
Excellent fluidity and low hot-tearing tendency for sand, permanent-mould and low-pressure casting; Sr/Na modification plus Ti-B grain refinement and directional solidification give best properties.
What surface finishes work on AL4?
Takes hard/protective anodising and chromate conversion well but the finish is grey and mottled; for cosmetic parts use powder coat or paint, and shot blast plus impregnation for pressure-tight housings.
AL4 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 |
|---|---|---|
| Sieutectic-forming element; Sr or Na modification usual | 8 – 10.5 | 9 |
| MgMg2Si precipitation hardening | 0.17 – 0.3 | 0.25 |
| Mnneutralises Fe needles | 0.2 – 0.5 | 0.35 |
| Felower limit (≈0.6 max) applies to sand/permanent-mould castings | ≤ 1 | 0.5 |
| Cuimpurity | ≤ 0.3 | — |
| Znimpurity | ≤ 0.3 | — |
| Tigrain refinement (Al-Ti-B) | ≤ 0.15 | 0.1 |
| Beoptional, restricts Mg oxidation | ≤ 0.1 | — |
| Al | balance | — |
AL4-T7 — frequently asked
What is AL4-T7 used for?
AL4-T7 is typically used for engine housings, gearbox casings, pump and valve bodies, intake manifolds, wheels and aircraft and structural fittings. In short: weldable Al-Si-Mg workhorse; best thermal conductivity here; pressure-tight T6 castings.
What is the yield strength of AL4-T7?
AL4-T7 has a typical yield strength of 160 MPa (23.2 ksi) and a tensile strength of 220 MPa (31.9 ksi) — weaker than 61% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is AL4-T7 easy to machine?
Reasonably — machinability is rated good (56/100, worse than 55% of aluminum grades). Machines cleanly in T6 with PCD or coated-carbide tools and high speeds; free silicon abrades HSS quickly, so use flood coolant and sharp positive-rake geometry.
Can AL4-T7 be welded?
Yes — weldability is rated very good (80/100). Readily TIG/MIG welded with ER4043 (or ER4047) filler; re-solution treat and age locally welded structural parts, and preheat/clean thoroughly to avoid porosity.
What surface finishes work on AL4-T7?
Takes hard/protective anodising and chromate conversion well but the finish is grey and mottled; for cosmetic parts use powder coat or paint, and shot blast plus impregnation for pressure-tight housings.
Can AL4-T7 be formed, bent or molded?
Excellent fluidity and low hot-tearing tendency for sand, permanent-mould and low-pressure casting; Sr/Na modification plus Ti-B grain refinement and directional solidification give best properties.
What is the maximum service temperature of AL4-T7?
AL4-T7 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between AL4-T6 and AL4-F?
T6 is the default condition — standard structural condition: best combination of strength, fatigue life and acceptable ductility for loaded castings. F: cheapest condition for lightly loaded, dimensionally stable housings where strength is not critical. Yield strength is 180 MPa in T6 versus 90 MPa in F.
Sources
- ГОСТ 1583-93 Сплавы алюминиевые литейные (АК9ч / АЛ4) — Межгосударственный совет по стандартизации (1993)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings (356.0) — ASTM International (2018)
- GB/T 1173 (ZL101A) (2013)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Aluminum Association Pink Sheets — Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot — The Aluminum Association (2018)
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.