Aluminum A356.2 · precip hard
Aluminum A356.2-T71
Properties of the T71 condition, compared with the other A356.2 tempers.
Softest heat-treated condition; picked for best machinability, minimum residual stress and long-term thermal stability.
What is A356.2-T71?
A356.2-T71 is A356.2 in the T71 condition — softest heat-treated condition; picked for best machinability, minimum residual stress and long-term thermal stability. A356.2-T71 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 207 MPa (30 ksi) — weaker than 68% of aluminum grades. Elongation at break is 3% and the elastic modulus is 72.4 GPa (10.5 Msi). A356.2-T71 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; T71 is available on request or by drawing note.
Advantages
- High service temperature — 205°C (401 °F), better than 95% of aluminum grades
- High electrical conductivity — 43 % IACS, better than 83% of aluminum grades
- Conducts heat well — 160 W/m·K (92.4 BTU/hr·ft·°F), better than 75% of aluminum grades
Limitations
- Limited formability — 10/100, worse than 81% of aluminum grades
- Limited ductility — 3%, worse than 79% of aluminum grades
A356.2-T71 properties
Typical room-temperature values for A356.2-T71 — 8 properties are specific to this condition; the rest are grade-level values shared by every A356.2 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
A356.2-T71 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).
Mechanical12
A356.2-T71 has a yield strength of 145 MPa (21 ksi) and a tensile strength of 207 MPa (30 ksi) — weaker than 68% of aluminum grades. Elongation at break is 3% and the elastic modulus is 72.4 GPa (10.5 Msi).
Thermal6
A356.2-T71 is rated for continuous service to 205°C (401 °F). It conducts heat at 160 W/m·K (92.4 BTU/hr·ft·°F), better than 75% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
A356.2-T71 conducts electricity at 43 % IACS, better than 83% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (65/100), better than 71% of aluminum grades.
Sustainability4
Producing a kilogram of A356.2-T71 takes about 195 MJ of energy and emits 12 kg of CO₂ — less than 86% of aluminum grades. Typical recycled content is 10%.
Manufacturability8
A356.2-T71's machinability is good (58/100, worse than 53% of aluminum grades); weldability very good (80/100); formability not recommended (10/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other A356.2 tempers and conditions
A356.2 is also supplied in 5 other conditions. The full side-by-side table is on the A356.2 overview.
- T6DefaultDefault structural temper: best balance of strength, ductility and fatigue life for wheels, knuckles and housings.186 MPa yield · 80 HB
- T61Choose when maximum strength and hardness are needed from permanent-mold castings and some ductility loss is acceptable.207 MPa yield · 90 HB
- T7Use where dimensional stability at elevated temperature and reduced residual stress matter more than peak strength.200 MPa yield · 75 HB
- T71Softest heat-treated condition; picked for best machinability, minimum residual stress and long-term thermal stability.145 MPa yield · 65 HB
- T51Low-cost temper for stability and modest strength gain without the distortion of solution quenching.138 MPa yield · 60 HB
- FPick for low-stress, dimensionally sensitive castings where heat-treat distortion or cost is unacceptable.83 MPa yield · 55 HB
Working with A356.2-T71
Is A356.2 easy to machine?
Machines cleanly in T6 with polished-flute carbide or PCD tooling and high speed; eutectic Si is abrasive so avoid HSS for production runs.
Can A356.2 be welded?
Readily TIG/MIG welded or repaired with 4043/4145 filler; re-solution and re-age welded structural castings to restore T6 properties.
Can A356.2 be formed, bent or molded?
Excellent fluidity and low hot-tearing for sand, permanent-mold, low-pressure and investment casting; Sr modification plus Ti-B refinement and directional solidification are needed for high-elongation T6 parts.
What surface finishes work on A356.2?
Takes hardcoat anodize and chromate/paint well but decorative sulfuric anodize turns grey; shot peening is common to raise fatigue life.
A356.2 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 | 6.5 – 7.5 | 7 |
| Mgaging element; Sr/Na modification typical | 0.3 – 0.45 | 0.35 |
| Fetight Fe limit distinguishes A356.2 from 356.2 | ≤ 0.12 | 0.08 |
| Cu | ≤ 0.1 | — |
| Mn | ≤ 0.05 | — |
| Zn | ≤ 0.05 | — |
| Tigrain refinement, usually with B | ≤ 0.2 | 0.12 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
A356.2-T71 — frequently asked
What is A356.2-T71 used for?
A356.2-T71 is typically used for aerospace castings, aircraft wheels, gearbox and accessory housings, structural airframe brackets, pump and valve bodies and automotive suspension components. In short: aerospace-spec A356; tight Mg/Fe control; heat-treatable.
What is the yield strength of A356.2-T71?
A356.2-T71 has a typical yield strength of 145 MPa (21 ksi) and a tensile strength of 207 MPa (30 ksi) — weaker than 68% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is A356.2-T71 easy to machine?
Reasonably — machinability is rated good (58/100, worse than 53% of aluminum grades). Machines cleanly in T6 with polished-flute carbide or PCD tooling and high speed; eutectic Si is abrasive so avoid HSS for production runs.
Can A356.2-T71 be welded?
Yes — weldability is rated very good (80/100). Readily TIG/MIG welded or repaired with 4043/4145 filler; re-solution and re-age welded structural castings to restore T6 properties.
What surface finishes work on A356.2-T71?
Takes hardcoat anodize and chromate/paint well but decorative sulfuric anodize turns grey; shot peening is common to raise fatigue life.
Can A356.2-T71 be formed, bent or molded?
Excellent fluidity and low hot-tearing for sand, permanent-mold, low-pressure and investment casting; Sr modification plus Ti-B refinement and directional solidification are needed for high-elongation T6 parts.
What is the maximum service temperature of A356.2-T71?
A356.2-T71 is rated for continuous use to about 205°C (401 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A356.2-T6 and A356.2-F?
T6 is the default condition — default structural temper: best balance of strength, ductility and fatigue life for wheels, knuckles and housings. F: pick for low-stress, dimensionally sensitive castings where heat-treat distortion or cost is unacceptable. Yield strength is 186 MPa in T6 versus 83 MPa in F.
Can FabDigit make parts in A356.2-T71?
Yes — A356.2-T71 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM B179 — Aluminum Alloys in Ingot and Molten Forms for Castings — ASTM International (2022)
- ASTM B26/B26M and B108/B108M — Aluminum-Alloy Sand and Permanent Mold Castings — ASTM International (2022)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Aluminum Association Registration Records (Teal Sheets / Pink Sheets) — The Aluminum Association (2018)
- GB/T 1173 (ZL101A ) — SAC (2013)
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.