Aluminum 357 · temper
Aluminum 357-T6
Properties of the T6 condition, compared with the other 357 tempers.
Standard high-strength condition for structural sand, permanent-mould and investment castings.
What is 357-T6?
357-T6 is 357 in the T6 temper — standard high-strength condition for structural sand, permanent-mould and investment castings. 357-T6 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 70% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72 GPa (10.4 Msi). 357-T6 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).
Advantages
- Readily welded — 85/100, better than 79% of aluminum grades
Limitations
- Limited formability — 10/100, worse than 81% of aluminum grades
357-T6 properties
Typical room-temperature values for 357-T6 — 13 properties are specific to this condition; the rest are grade-level values shared by every 357 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
357-T6 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
357-T6 has a yield strength of 275 MPa (39.9 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 70% of aluminum grades. Elongation at break is 5% and the elastic modulus is 72 GPa (10.4 Msi).
Thermal6
357-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
357-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 357-T6 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability7
357-T6's machinability is good (68/100, better than 68% of aluminum grades); weldability excellent (85/100); 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 357 tempers and conditions
357 is also supplied in 4 other conditions. The full side-by-side table is on the 357 overview.
- T62Choose when the highest static strength is required and elongation can be traded down; common for HIPed/densified premium castings.310 MPa yield · 105 HB
- T61Aerospace peak-aged condition (typically A357 with Be/Ti refinement) for maximum strength with useful ductility.290 MPa yield · 100 HB
- T6Standard high-strength condition for structural sand, permanent-mould and investment castings.275 MPa yield · 90 HB
- T7Pick for dimensional/thermal stability and best toughness at slightly reduced strength (elevated-temperature service).235 MPa yield · 80 HB
- T51Use for moderate strength with minimum distortion/residual stress, since no solution quench is applied.150 MPa yield · 65 HB
Working with 357-T6
Is 357 easy to machine?
Machines cleanly in T6 with sharp positive-rake carbide or PCD tooling and high speeds; eutectic Si is abrasive, so avoid HSS for volume work and flood-cool to prevent built-up edge.
Can 357 be welded?
Very good gas-tungsten/laser weldability and weld-repairable per AMS/AWS practice with 4043 or 4047 filler; re-solution + re-age locally welded T6 parts to restore properties.
Can 357 be formed, bent or molded?
Foundry alloy with excellent fluidity for thin-wall sand, permanent-mould, low-pressure and investment casting; Sr/Na modification plus Ti-B refinement and controlled solidification (or HIP) maximize elongation — not a cold-forming alloy.
What surface finishes work on 357?
Takes chromate/anodic protective coatings and paint well; hard anodize is practical but decorative anodizing turns grey and blotchy from the Si phase, so most parts are painted, chem-filmed or powder coated.
357 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 |
| Mgraised vs A356 for higher aged strength | 0.45 – 0.6 | 0.52 |
| Felow Fe required for ductility | ≤ 0.15 | — |
| Cu | ≤ 0.05 | — |
| Mn | ≤ 0.03 | — |
| Zn | ≤ 0.05 | — |
| Tigrain refinement | ≤ 0.2 | 0.12 |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
357-T6 — frequently asked
What is 357-T6 used for?
357-T6 is typically used for aerospace structural castings, helicopter gearbox and transmission housings, investment-cast brackets and fittings, low-pressure cast wheels, pump and valve housings and thin-wall pressure-tight enclosures. In short: premium sand cast.
What is the yield strength of 357-T6?
357-T6 has a typical yield strength of 275 MPa (39.9 ksi) and a tensile strength of 330 MPa (47.9 ksi) — stronger than 70% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is 357-T6 easy to machine?
Reasonably — machinability is rated good (68/100, better than 68% of aluminum grades). Machines cleanly in T6 with sharp positive-rake carbide or PCD tooling and high speeds; eutectic Si is abrasive, so avoid HSS for volume work and flood-cool to prevent built-up edge.
Can 357-T6 be welded?
Yes — weldability is rated excellent (85/100). Very good gas-tungsten/laser weldability and weld-repairable per AMS/AWS practice with 4043 or 4047 filler; re-solution + re-age locally welded T6 parts to restore properties.
What surface finishes work on 357-T6?
Takes chromate/anodic protective coatings and paint well; hard anodize is practical but decorative anodizing turns grey and blotchy from the Si phase, so most parts are painted, chem-filmed or powder coated.
Can 357-T6 be formed, bent or molded?
Foundry alloy with excellent fluidity for thin-wall sand, permanent-mould, low-pressure and investment casting; Sr/Na modification plus Ti-B refinement and controlled solidification (or HIP) maximize elongation — not a cold-forming alloy.
What is the maximum service temperature of 357-T6?
357-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 357-T6?
Yes — 357-T6 is available for CNC machining with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- Aluminum Association Teal Sheets — Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot — The Aluminum Association (2015)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- ASTM B108/B108M — Aluminum-Alloy Permanent Mold Castings — ASTM International (2019)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- GB/T 1173 (ZL101A comparable grade) — 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.