Aluminum A357 · temper
Aluminum A357-T6
Properties of the T6 condition, compared with the other A357 tempers.
Standard supply condition: best balance of strength and ductility for structural sand, permanent-mould and investment castings.
What is A357-T6?
A357-T6 is A357 in the T6 temper — standard supply condition: best balance of strength and ductility for structural sand, permanent-mould and investment castings. A357-T6 has a yield strength of 276 MPa (40 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 71% of aluminum grades. Elongation at break is 6% and the elastic modulus is 72 GPa (10.4 Msi). A357-T6 has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 555°C (1,031 °F).
Limitations
- Limited formability — 10/100, worse than 81% of aluminum grades
A357-T6 properties
Typical room-temperature values for A357-T6 — 13 properties are specific to this condition; the rest are grade-level values shared by every A357 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
A357-T6 has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 555°C (1,031 °F).
Mechanical12
A357-T6 has a yield strength of 276 MPa (40 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 71% of aluminum grades. Elongation at break is 6% and the elastic modulus is 72 GPa (10.4 Msi).
Thermal6
A357-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 152 W/m·K (87.8 BTU/hr·ft·°F), better than 66% of aluminum grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
A357-T6 conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of A357-T6 takes about 190 MJ of energy and emits 12.5 kg of CO₂ — less than 89% of aluminum grades. Typical recycled content is 20%.
Manufacturability8
A357-T6's machinability is good (65/100, better than 62% of aluminum grades); weldability very good (75/100); 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 A357 tempers and conditions
A357 is also supplied in 4 other conditions. The full side-by-side table is on the A357 overview.
- T62Aerospace premium-quality castings (AMS-A-21180 class) with tightly controlled soundness and certified minimum properties.305 MPa yield · 110 HB
- T61Pick when maximum strength/hardness is wanted from permanent-mould or chill castings and some ductility can be traded away.290 MPa yield · 105 HB
- T6Standard supply condition: best balance of strength and ductility for structural sand, permanent-mould and investment castings.276 MPa yield · 100 HB
Working with A357-T6
Is A357 easy to machine?
Machines freely with polished-flute carbide or PCD tooling at high speed; eutectic Si is abrasive so avoid HSS for production, and use flood coolant to prevent build-up on Mg-rich chips.
Can A357 be welded?
Readily TIG/plasma repair-welded with 4043 or 4047 filler; re-solution treat and age after major weld repair to restore T6 properties and avoid HAZ softening.
Can A357 be formed, bent or molded?
Excellent fluidity and low hot-tearing tendency — suits thin-wall sand, investment, permanent-mould and low-pressure casting; directional solidification plus Sr/Na modification and degassing are needed for full T6 ductility.
What surface finishes work on A357?
Takes hard (grey) sulfuric anodize, chromate/chrome-free conversion coating and paint well; clear decorative anodize is patchy because of the high Si, and Be-containing dust must be captured during grinding/polishing.
A357 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 |
| Mgmain strengthening addition (Mg2Si) | 0.4 – 0.7 | 0.55 |
| Tigrain refinement | 0.1 – 0.2 | 0.15 |
| Bemodifies Fe-phases and limits Mg oxidation; requires fume/dust control | 0.04 – 0.07 | 0.05 |
| Femax; low Fe essential for ductility | ≤ 0.2 | — |
| Cu | ≤ 0.2 | — |
| Mn | ≤ 0.1 | — |
| Zn | ≤ 0.1 | — |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
A357-T6 — frequently asked
What is A357-T6 used for?
A357-T6 is typically used for aerospace structural castings, helicopter gearbox and transmission housings, pressure-tight thin-wall housings, racing suspension uprights and knuckles, investment-cast impellers and pump bodies and UAV and missile structural brackets. In short: premium aero cast.
What is the yield strength of A357-T6?
A357-T6 has a typical yield strength of 276 MPa (40 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 71% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is A357-T6 easy to machine?
Reasonably — machinability is rated good (65/100, better than 62% of aluminum grades). Machines freely with polished-flute carbide or PCD tooling at high speed; eutectic Si is abrasive so avoid HSS for production, and use flood coolant to prevent build-up on Mg-rich chips.
Can A357-T6 be welded?
Yes — weldability is rated very good (75/100). Readily TIG/plasma repair-welded with 4043 or 4047 filler; re-solution treat and age after major weld repair to restore T6 properties and avoid HAZ softening.
What surface finishes work on A357-T6?
Takes hard (grey) sulfuric anodize, chromate/chrome-free conversion coating and paint well; clear decorative anodize is patchy because of the high Si, and Be-containing dust must be captured during grinding/polishing.
Can A357-T6 be formed, bent or molded?
Excellent fluidity and low hot-tearing tendency — suits thin-wall sand, investment, permanent-mould and low-pressure casting; directional solidification plus Sr/Na modification and degassing are needed for full T6 ductility.
What is the maximum service temperature of A357-T6?
A357-T6 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 A357-T6?
Yes — A357-T6 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)
- ASM Handbook, Vol. 2: Properties and Selection — Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Handbook, Vol. 15: Casting — ASM International (2008)
- ASTM B686 / ASTM B26 — Aluminum-Alloy Castings, High Strength / Sand Castings — ASTM International (2018)
- AMS-A-21180 — Aluminum-Alloy Castings, High Strength — SAE International (2019)
- MMPDS-17 aluminium casting alloy data — Battelle Memorial Institute (2022)
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.