Aluminum A357
AA A357 · UNS A13570 · EN AlSi7Mg0.6
A357 (A357.0 / AlSi7Mg0.6) is a beryllium-bearing, low-iron Al-7Si-0.6Mg hypoeutectic casting alloy with excellent fluidity and pressure tightness; after T6/T61 heat treatment its strength and elongation are clearly above A356.
A357 tempers and conditions
A357 is supplied in 5 conditions, soft to hard.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cooled from hot working and artificially aged | Low-cost stabilising temper when full solution treatment distortion cannot be tolerated; strength well below T6. | 150 | 205 | 3 | 65 HB | 42 % IACS |
Solution heat treated and artificially aged | Standard supply condition: best balance of strength and ductility for structural sand, permanent-mould and investment castings. | 276 | 345 | 6 | 100 HB | 39 % IACS |
hot isostatically pressed then solution treated and aged | For fatigue- and fracture-critical aerospace investment castings: HIP closes residual porosity and raises ductility and fatigue life at T6 strength. | 285 | 350 | 10 | 100 HB | 39 % IACS |
T6 variant, underaged | Pick when maximum strength/hardness is wanted from permanent-mould or chill castings and some ductility can be traded away. | 290 | 360 | 5 | 105 HB | 39 % IACS |
T6, heat treated by the user | Aerospace premium-quality castings (AMS-A-21180 class) with tightly controlled soundness and certified minimum properties. | 305 | 380 | 6 | 110 HB | 38 % IACS |
What is A357?
A357 (A357.0 / AlSi7Mg0.6) is a beryllium-bearing, low-iron Al-7Si-0.6Mg hypoeutectic casting alloy with excellent fluidity and pressure tightness; after T6/T61 heat treatment its strength and elongation are clearly above A356. It is specified for thin-wall, high-integrity sand, permanent-mould, investment and low-pressure castings in aerospace and motorsport. Iron must be held low and combined with rapid solidification or HIP to reach handbook strength, the beryllium content brings melting and grinding hygiene controls, high Si spoils clear anodizing, and the alloy softens in long-term service above about 150 °C. A357 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). A357 has a yield strength of 276 MPa (40 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 72% of aluminum grades. Elongation at break is 6% and the elastic modulus is 72 GPa (10.4 Msi).
What is A357 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
- UAV and missile structural brackets
- Low-pressure cast wheels
Limitations
- Limited formability — 10/100, worse than 80% of aluminum grades
A357 properties
Typical room-temperature values; bars are the position among aluminum grades.
Physical3
A357 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 has a yield strength of 276 MPa (40 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 72% of aluminum grades. Elongation at break is 6% and the elastic modulus is 72 GPa (10.4 Msi).
Thermal6
A357 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 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 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's machinability is good (65/100, better than 62% of aluminum grades); weldability very good (75/100); formability not recommended (10/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. A357 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A357
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.
Manufacturability
The process limits FabDigit applies to A357. Every A357 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better65 / 100 |
|---|---|
| ISO material group | N.1 |
| Cutting speed (rough / finish) | 350 / 420 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 8× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
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 |
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.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Passivation
Conversion Coating
PVD Coating
Equivalent designations
Standards and trade names that resolve to Aluminum A357 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A13570
- EN / DIN / Werkstoff-Nr.
- AlSi7Mg0.6
How much does A357 cost?
A357 is a standard-cost aluminum ($$), cheaper than about 80% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A357 — frequently asked
What is A357 used for?
A357 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?
A357 has a typical yield strength of 276 MPa (40 ksi) and a tensile strength of 345 MPa (50 ksi) — stronger than 72% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is A357 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 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?
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 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?
A357 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.
How much does A357 cost?
A357 is a standard-cost aluminum ($$), cheaper than about 80% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in A357?
Yes — A357 is available for CNC machining; every part is priced by an engineer rather than instantly. 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; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.