A380 is the default aluminum alloy for high-pressure die casting. If you are quoting an aluminum die cast part and no alloy is specified, A380 is almost certainly what the supplier will assume. It accounts for the largest share of aluminum die casting production globally, and for good reason — it balances castability, mechanical strength, thermal performance, and cost better than any other single grade.
At Meituo, A380 and its equivalents (ADC10, ADC12) are the alloys we run through our die casting machines most often. This article covers the composition, properties, and practical applications of A380 based on what we see in actual production.
Chemical Composition of A380 Aluminum
A380 belongs to the Al-Si-Cu family of casting alloys. Silicon and copper are the two main alloying additions, each serving a specific purpose in the casting process.
| Element | Content Range (wt%) | Role |
|---|---|---|
| Silicon (Si) | 7.5 – 9.5% | Improves fluidity, reduces shrinkage, enhances wear resistance |
| Copper (Cu) | 3.0 – 4.0% | Increases tensile strength and hardness |
| Iron (Fe) | ≤1.3% | Prevents die soldering (sticking to mold), but excess reduces ductility |
| Zinc (Zn) | ≤3.0% | Minor contribution, generally kept low |
| Magnesium (Mg) | ≤0.1% | Trace level, limited effect in A380 |
| Manganese (Mn) | ≤0.5% | Converts harmful iron phases to less detrimental forms |
| Aluminum (Al) | Balance (~80–90%) | Base metal |
The high silicon content is what gives A380 its excellent fluidity during casting. Molten A380 flows easily into complex mold geometries and thin-wall sections with minimal risk of cold shuts or incomplete fills. The copper content adds strength but comes with a trade-off — it reduces corrosion resistance compared to copper-free alloys like A356.
Mechanical Properties
| Property | Typical Value (As-Cast) |
|---|---|
| Ultimate Tensile Strength | 325 MPa (47 ksi) |
| Yield Strength (0.2% offset) | 160 MPa (23 ksi) |
| Elongation at Break | 3.5% |
| Hardness | 80 HB |
| Fatigue Strength (10⁷ cycles) | 145 MPa |
| Shear Strength | 190 MPa |
A380 delivers solid strength for a casting alloy. The 325 MPa tensile strength is adequate for most structural and functional die cast parts — engine brackets, transmission housings, electronic enclosures, appliance components. The 3.5% elongation tells you this is not a ductile alloy. It will not bend much before it cracks. For parts that need to absorb impact or deform without breaking, A356 with its higher elongation after T6 heat treatment is the better pick.
Physical Properties
| Property | Value |
|---|---|
| Density | 2.71 g/cm³ |
| Melting Range | 540 – 595°C (1000 – 1100°F) |
| Thermal Conductivity | 96 W/m·K |
| Electrical Conductivity | 23% IACS |
| Coefficient of Thermal Expansion | 21.8 μm/m·°C |
The thermal conductivity of 96 W/m·K is decent for a die casting alloy and makes A380 a reasonable choice for heat dissipation applications like LED housings and electronic enclosures. If thermal management is the primary requirement, alloys with lower copper content (like A360) offer better conductivity, but A380 handles most general-purpose heat sink duties adequately.
A380 Equivalent Grades
The same alloy goes by different names depending on what standard system your customer or drawing uses.
| Standard | Designation | Notes |
|---|---|---|
| ASTM (US) | A380.0 (ASTM B85) | Primary designation |
| Aluminum Association (US) | AA 380.0 | Same as ASTM |
| JIS (Japan) | ADC10 | Closest equivalent, very similar composition |
| EN (Europe) | EN AC-46000 (AlSi9Cu3) | European standard equivalent |
| BS (UK) | LM24 | British standard equivalent |
| GB (China) | YL104 (YZAlSi9Cu4) | Chinese national standard |
ADC12 is sometimes listed as an A380 equivalent, but this is not precise. ADC12 has a narrower copper range (1.5–3.5% vs A380's 3.0–4.0%) and slightly higher silicon ceiling (9.6–12% vs 7.5–9.5%). In practice, ADC12 is closer to A383. For most applications the performance difference is minor, but if a drawing specifies one grade, do not substitute the other without checking with your customer.
Castability and Processing
A380 is processed by cold-chamber high-pressure die casting (HPDC). The alloy melts at around 595°C, which is too hot for the submerged injection components of a hot-chamber machine. Molten metal is ladled into a separate injection sleeve and then forced into the die cavity at high speed and pressure.
Key casting characteristics:
- Excellent fluidity — fills thin walls and complex geometries reliably
- Good resistance to hot cracking during solidification
- Good pressure tightness — suitable for parts that need to hold fluid or gas
- Relatively low die soldering tendency (iron content helps here)
- Short cycle times achievable due to fast solidification
One important note: A380 is not compatible with T6 heat treatment when produced by HPDC. The high-pressure process traps micro gas bubbles inside the casting. T6 treatment involves heating to around 500°C, which causes these bubbles to expand and blister the surface. Minor stress-relief (T5) is possible, but full solution heat treatment is limited to gravity or squeeze cast A380 parts.
Surface Treatment Options
A380 accepts most common surface treatments, but with some caveats:
- Powder coating and painting: The most reliable and widely used finishes for A380. Proper pre-treatment (chromate conversion or zirconium coating) is essential for adhesion.
- Electroplating: Possible with proper surface preparation, but the as-cast surface must be smooth and porosity-free in the plating area.
- Anodizing: Not recommended for decorative purposes. The high silicon content produces a dark gray, uneven anodic film. Functional anodizing for wear resistance is possible but cosmetically poor.
- Chromate conversion coating: Works well as a standalone corrosion barrier for internal parts.
Common Applications
A380's balanced properties make it a generalist alloy. The applications we see most often include:
- Automotive: engine brackets, transmission housings, valve bodies, intake manifolds, structural brackets
- Home appliances: motor housings, fan wheels, internal structural parts, compressor components
- Electronics: LED lamp housings, telecom equipment enclosures, connector housings, heat sinks
- Industrial equipment: pump housings, gear cases, pneumatic tool housings
At Meituo, a significant portion of our aluminum die casting production uses A380 and its equivalent grades. Our cold-chamber die casting machines range from 160T to 1250T, covering part sizes from small connectors to medium structural components.
When to Choose A380 — and When Not To
Choose A380 when you need a general-purpose die casting alloy with good strength, good castability, and competitive material cost. It is the safe default for most HPDC applications.
Consider a different alloy when:
- You need high ductility or impact resistance → A356 (with T6 heat treatment, gravity or squeeze cast)
- You need superior corrosion resistance → A360 or 518 (lower copper content)
- You need better filling of very thin or complex geometries → ADC12/A383 (higher silicon)
- You need decorative anodizing → 518 or 5000-series wrought alloys (not castable by HPDC)
Get the Right Alloy for Your Project
If you are unsure whether A380 is the right material for your part, send us your drawing and application requirements. Our engineering team will review the geometry, wall thickness, operating environment, and surface finish needs, then recommend the most suitable alloy and process combination.
