Aluminum 384
AA 384 · UNS A03840 · EN AlSi11Cu3 · also SC114A
384 (384.0 / A384.0, broadly equivalent to JIS ADC12 and AlSi11Cu3) is a high-silicon, copper-bearing Al-Si-Cu high-pressure die-casting alloy and one of the highest-volume cast aluminium materials in use.
384 tempers and conditions
384 is supplied in one standard condition, F.
What is 384?
384 (384.0 / A384.0, broadly equivalent to JIS ADC12 and AlSi11Cu3) is a high-silicon, copper-bearing Al-Si-Cu high-pressure die-casting alloy and one of the highest-volume cast aluminium materials in use. The near-eutectic silicon content gives excellent fluidity and hot-tear resistance, while copper raises strength and hardness and keeps machinability good, suiting thin-wall, complex engine and electronics structures. Limits are low elongation (about 2-3 %), reduced corrosion resistance and poor anodized appearance from the copper, and internal gas porosity that makes castings effectively unweldable and not heat-treatable. 380 is the lower-silicon alternative. 384 has a density of 2.82 g/cm³ (0.102 lb/in³), heavier than 89% of aluminum grades. It melts at 482°C (900 °F). 384 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 58% of aluminum grades. Elongation at break is 2.5% and the elastic modulus is 71 GPa (10.3 Msi).
What is 384 used for?
- Engine cases and covers
- Transmission housings
- Electronic device housings and frames
- Thin-wall complex die castings
- Motor and pump housings
- Automotive brackets and covers
Advantages
- High service temperature — 175°C (347 °F), better than 83% of aluminum grades
Limitations
- Low electrical conductivity — 23 % IACS, worse than 97% of aluminum grades
- Poor heat conductor — 96 W/m·K (55.5 BTU/hr·ft·°F), worse than 95% of aluminum grades
- Limited formability — 5/100, worse than 94% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Limited ductility — 2.5%, worse than 83% of aluminum grades
384 properties
Typical room-temperature values; bars are the position among aluminum grades.
Physical3
384 has a density of 2.82 g/cm³ (0.102 lb/in³), heavier than 89% of aluminum grades. It melts at 482°C (900 °F).
Mechanical13
384 has a yield strength of 165 MPa (23.9 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 58% of aluminum grades. Elongation at break is 2.5% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
384 is rated for continuous service to 175°C (347 °F). It conducts heat at 96 W/m·K (55.5 BTU/hr·ft·°F), worse than 95% of aluminum grades. Thermal expansion is 21 µm/m·K (11.7 µin/in·°F).
Electrical3
384 conducts electricity at 23 % IACS, worse than 97% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (38/100), worse than 79% of aluminum grades.
Sustainability4
Producing a kilogram of 384 takes about 205 MJ of energy and emits 12 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 95%.
Manufacturability8
384's machinability is good (60/100, worse than 51% of aluminum grades); weldability poor (25/100); formability not recommended (5/100).
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. 384 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 384
Is 384 easy to machine?
Machines freely with sharp carbide or PCD tools and flood coolant; the hard eutectic Si is abrasive, so favour PCD for high-volume drilling/milling and expect short tool life with HSS.
Can 384 be welded?
Effectively non-weldable as a die casting (entrapped gas porosity blows out and 3–4 % Cu promotes hot cracking); join by mechanical fastening, self-piercing rivets or adhesive, use TIG only for cosmetic repair.
Can 384 be formed, bent or molded?
Excellent high-pressure die casting alloy — near-eutectic fluidity fills 1–2 mm walls, low hot-tear tendency and good die life; not heat-treatable and not cold formable.
Manufacturability
The process limits FabDigit applies to 384. Every 384 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better60 / 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 |
384 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 |
|---|---|---|
| Sinear-eutectic, drives fluidity | 10.5 – 12 | 11.2 |
| Cu | 3 – 4.5 | 3.8 |
| Fedie casting limit; 1.0 max for permanent mold | ≤ 1.3 | 0.9 |
| Mn | ≤ 0.5 | 0.25 |
| Mg | ≤ 0.1 | 0.05 |
| Ni | ≤ 0.5 | |
| ZnA384.0 limits Zn to 1.0 % | ≤ 3 | 1 |
| Sn | ≤ 0.35 | |
| Others (each)total others per ASTM B85 | ≤ 0.5 | |
| Al | balance |
What surface finishes work on 384?
Conversion coat (chromate-free), powder coat or paint for corrosion protection; anodizing gives a dark, mottled film, and porosity can bleed during plating so impregnate or use vacuum-assist casting first.
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 384 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A03840
- EN / DIN / Werkstoff-Nr.
- AlSi11Cu3
- Trade names
- SC114A
How much does 384 cost?
384 is a budget-cost aluminum ($), cheaper than about 90% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
384 — frequently asked
What is 384 used for?
384 is typically used for engine cases and covers, transmission housings, electronic device housings and frames, thin-wall complex die castings, motor and pump housings and automotive brackets and covers. In short: high-fluidity die cast.
What is the yield strength of 384?
384 has a typical yield strength of 165 MPa (23.9 ksi) and a tensile strength of 330 MPa (47.9 ksi) — weaker than 58% of aluminum grades.
Is 384 easy to machine?
Reasonably — machinability is rated good (60/100, worse than 51% of aluminum grades). Machines freely with sharp carbide or PCD tools and flood coolant; the hard eutectic Si is abrasive, so favour PCD for high-volume drilling/milling and expect short tool life with HSS.
Can 384 be welded?
Not readily — weldability is rated poor (25/100). Effectively non-weldable as a die casting (entrapped gas porosity blows out and 3–4 % Cu promotes hot cracking); join by mechanical fastening, self-piercing rivets or adhesive, use TIG only for cosmetic repair.
What surface finishes work on 384?
Conversion coat (chromate-free), powder coat or paint for corrosion protection; anodizing gives a dark, mottled film, and porosity can bleed during plating so impregnate or use vacuum-assist casting first.
Can 384 be formed, bent or molded?
Excellent high-pressure die casting alloy — near-eutectic fluidity fills 1–2 mm walls, low hot-tear tendency and good die life; not heat-treatable and not cold formable.
What is the maximum service temperature of 384?
384 is rated for continuous use to about 175°C (347 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 384 cost?
384 is a budget-cost aluminum ($), cheaper than about 90% 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 384?
Yes — 384 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
- ASTM B85/B85M — Aluminum-Alloy Die Castings — ASTM International (2018)
- 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 — ASM International (1990)
- NADCA Product Specification Standards for Die Castings — North American Die Casting Association (2018)
- JIS H 5302 (ADC12) / GB/T 15115 (YZAlSi11Cu3) — JISC / SAC (2009)
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.