Aluminum A390
AA A390 · UNS A13900 · EN AlSi17Cu4Mg hyper
A390 is a hypereutectic Al–17Si–4.5Cu–0.55Mg casting alloy whose microstructure contains primary silicon crystals, giving exceptional wear resistance, high stiffness, low thermal expansion and good elevated-temperature strength.
A390 tempers and conditions
A390 is supplied in 4 conditions, soft to hard.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Cooled from hot working and artificially aged | Low-cost stabilising age of permanent-mould or die castings to relieve stress and steady dimensions with a small strength gain. | 195 | 200 | 1 | 110 HB | 26 % IACS |
As fabricated | Standard high-volume condition: die-cast A390/B390 parts used as-cast for wear surfaces and thin-wall housings. | 240 | 280 | 1 | 120 HB | 25 % IACS |
Solution heat treated and overaged (stabilized) | Choose when dimensional stability and property retention at 150–230 °C matter more than peak strength. | 240 | 250 | 1 | 125 HB | 28 % IACS |
Solution heat treated and artificially aged | Pick for maximum hardness and strength on permanent-mould/low-pressure castings, e.g. pistons and pump bodies. | 275 | 285 | 0.8 | 145 HB | 27 % IACS |
What is A390?
A390 is a hypereutectic Al–17Si–4.5Cu–0.55Mg casting alloy whose microstructure contains primary silicon crystals, giving exceptional wear resistance, high stiffness, low thermal expansion and good elevated-temperature strength. It is the classic linerless engine-block, compressor-body and piston alloy, cast by die casting or permanent mould and usually run in F, T5, T6 or T7. The trade-offs are essentially zero ductility (elongation <1 %), very abrasive machining that demands PCD/diamond tooling, poor weldability and only moderate corrosion resistance because of the 4–5 % Cu. A390 has a density of 2.73 g/cm³ (0.0986 lb/in³), heavier than 61% of aluminum grades. It melts at 507°C (945 °F). A390 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 280 MPa (40.6 ksi) — stronger than 63% of aluminum grades. Elongation at break is 1% and the elastic modulus is 81 GPa (11.7 Msi).
What is A390 used for?
- Linerless engine cylinder blocks
- Compressor pistons
- Air-conditioning compressor bodies
- Pistons and wear sleeves
- Pump housings with abrasive service
- Small-engine cylinders
- Dimensionally stable machine components
Advantages
- Stiff — 81 GPa (11.7 Msi), better than 96% of aluminum grades
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
Limitations
- Limited formability — 3/100, worse than 100% of aluminum grades
- Low fracture toughness — 12 MPa·√m (10.9 ksi·√in), worse than 99% of aluminum grades
- Limited ductility — 1%, worse than 95% of aluminum grades
- Low electrical conductivity — 25 % IACS, worse than 92% of aluminum grades
- Difficult to machine — 30/100, worse than 92% of aluminum grades
A390 properties
Typical room-temperature values; bars are the position among aluminum grades.
Physical3
A390 has a density of 2.73 g/cm³ (0.0986 lb/in³), heavier than 61% of aluminum grades. It melts at 507°C (945 °F).
Mechanical14
A390 has a yield strength of 240 MPa (34.8 ksi) and a tensile strength of 280 MPa (40.6 ksi) — stronger than 63% of aluminum grades. Elongation at break is 1% and the elastic modulus is 81 GPa (11.7 Msi).
Thermal6
A390 is rated for continuous service to 200°C (392 °F). It conducts heat at 134 W/m·K (77.4 BTU/hr·ft·°F), worse than 60% of aluminum grades. Thermal expansion is 18 µm/m·K (10 µin/in·°F).
Electrical3
A390 conducts electricity at 25 % IACS, worse than 92% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 69% of aluminum grades.
Sustainability4
Producing a kilogram of A390 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 55%.
Manufacturability8
A390's machinability is poor (30/100, worse than 92% of aluminum grades); weldability poor (20/100); formability not recommended (3/100).
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. A390 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A390
Is A390 easy to machine?
Highly abrasive primary Si — use PCD or diamond-coated tooling, high speed / light feed, copious coolant; carbide life is very short and honed bores need diamond stones.
Can A390 be welded?
Essentially not weldable for structural joints (hot cracking, Cu content, gas porosity); repair only by TIG with 4145/4047 filler on non-critical areas.
Can A390 be formed, bent or molded?
Die casting or permanent-mould casting only; melt at 730–790 °C with phosphorus refinement and controlled cooling to keep primary Si fine and dispersed — no cold forming.
Manufacturability
The process limits FabDigit applies to A390. Every A390 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Good30 / 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 |
A390 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 |
|---|---|---|
| Siprimary silicon crystals give wear resistance | 16 – 18 | 17 |
| Cu | 4 – 5 | 4.5 |
| Mg | 0.45 – 0.65 | 0.55 |
| FeA390.0 limit; 390.0/B390.0 allow up to 1.3 | ≤ 0.5 | 0.3 |
| MnB390.0 allows 0.50 | ≤ 0.1 | |
| ZnB390.0 allows 1.5 | ≤ 0.1 | |
| Ti | ≤ 0.2 | |
| NiB390.0 limit | ≤ 0.1 | |
| Padded as refiner for primary Si (not always a spec element) | 0 – 0.01 | 0.01 |
| Others (each)total 0.20 max | ≤ 0.1 | |
| Al | balance |
What surface finishes work on A390?
Hard-anodize (Type III) for bore wear surfaces, otherwise chromate/phosphate conversion or paint; decorative anodizing and bright polishing look grey and blotchy from the Si phase.
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 A390 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A13900
- EN / DIN / Werkstoff-Nr.
- AlSi17Cu4Mg hyper
- Similar grades
- ZL109
How much does A390 cost?
A390 is a standard-cost aluminum ($$), cheaper than about 81% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A390 — frequently asked
What is A390 used for?
A390 is typically used for linerless engine cylinder blocks, compressor pistons, air-conditioning compressor bodies, pistons and wear sleeves, pump housings with abrasive service and small-engine cylinders. In short: hypereutectic Al-Si wear cast.
What is the yield strength of A390?
A390 has a typical yield strength of 240 MPa (34.8 ksi) and a tensile strength of 280 MPa (40.6 ksi) — stronger than 63% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is A390 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 92% of aluminum grades). Highly abrasive primary Si — use PCD or diamond-coated tooling, high speed / light feed, copious coolant; carbide life is very short and honed bores need diamond stones.
Can A390 be welded?
Not readily — weldability is rated poor (20/100). Essentially not weldable for structural joints (hot cracking, Cu content, gas porosity); repair only by TIG with 4145/4047 filler on non-critical areas.
What surface finishes work on A390?
Hard-anodize (Type III) for bore wear surfaces, otherwise chromate/phosphate conversion or paint; decorative anodizing and bright polishing look grey and blotchy from the Si phase.
Can A390 be formed, bent or molded?
Die casting or permanent-mould casting only; melt at 730–790 °C with phosphorus refinement and controlled cooling to keep primary Si fine and dispersed — no cold forming.
What is the maximum service temperature of A390?
A390 is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does A390 cost?
A390 is a standard-cost aluminum ($$), cheaper than about 81% 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 A390?
Yes — A390 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/Teal Sheets) — The Aluminum Association (2018)
- ASTM B85 / B108 — Aluminum-Alloy Die Castings and Permanent Mold Castings — ASTM (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys (390.0/A390.0/B390.0 data) — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
- Hypereutectic Al-Si die casting alloy datasheets (engine block / compressor applications) — Foundry alloy producers (2020)
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.