A383 Aluminum Alloy: Composition, Properties & Die Casting Applications
A383 is an aluminum-silicon die casting alloy — a modified version of A380 — engineered for improved die-filling and better resistance to hot cracking. It is one of the most widely used aluminum die casting alloys for thin-walled, complex or high-fill parts, balancing castability, strength and economy. Where A380 is the general-purpose workhorse, A383 is chosen when a casting has intricate geometry, thin sections, or a tendency to crack as it solidifies.
Typical Composition (indicative)
A383 is an Al-Si-Cu alloy; its slightly higher silicon (vs A380) improves fluidity and fill while controlled copper supports strength.
| Element | Typical range (indicative, wt%) |
|---|---|
| Silicon (Si) | ~9.5–11.5 |
| Copper (Cu) | ~2.0–3.0 |
| Iron (Fe) | ≤~1.3 |
| Magnesium (Mg) | ≤~0.10 |
| Manganese (Mn) | ≤~0.50 |
| Zinc (Zn) | ≤~3.0 |
| Aluminum (Al) | Balance |
Composition ranges are indicative and must be verified against the applicable specification (Aluminum Association / ASTM B85) and the supplier's certified chemistry.
Mechanical and Physical Properties (indicative)
In the as-cast (F) condition A383 offers properties similar to A380, trading a little peak strength for superior castability.
| Property | Typical value (indicative) |
|---|---|
| Ultimate tensile strength | ~310 MPa (~45 ksi) |
| Yield strength (0.2%) | ~150 MPa (~22 ksi) |
| Elongation | ~3.5% |
| Brinell hardness | ~75 HB |
| Density | ~2.74 g/cm³ |
| Melting range | ~516–582 °C |
Values indicative for typical die-cast sections; vary with wall thickness, process and cooling. Verify against datasheets and standards.
A380 vs A383: What's the Difference?
A383 typically carries slightly more silicon (better fluidity and die-fill for thin/complex sections); it resists hot tearing better during solidification; A380 offers marginally higher strength and hardness. Choose A380 for broad general use; choose A383 when castability, thin walls or crack-sensitivity drive the decision. In short, A383 trades a small amount of strength for meaningfully better castability and hot-crack resistance.
Typical Die Casting Applications
A383's fill characteristics suit detailed, thin-walled, pressure-tight housings: electronic/electrical enclosures and connector housings; telecom and lighting housings; pump, motor and gearbox housings; automotive brackets, covers and structural parts; thin-walled or intricately cored parts where A380 may underfill or crack.
Why Choose A383
A383 is selected when a part demands clean, complete fills and crack-free castings without sacrificing the economy and machinability of aluminum die casting. It runs well in high-pressure die casting, holds tight detail and delivers consistent, pressure-tight parts.
Frequently Asked Questions
What is the difference between A380 and 383? A383 is a modified A380 with slightly higher silicon, giving better die-fill and stronger hot-crack resistance, at a small cost in peak strength. A380 is the general-purpose default; A383 is preferred for thin-walled or complex, crack-prone parts. Verify exact chemistries against the applicable specification.
Is A383 good for thin-wall die casting? Yes — its improved fluidity and fill suit thin sections and intricate geometries where lower-fluidity alloys may underfill.
Does A383 need heat treatment? A383 is typically used as-cast (F) for die casting and not normally heat treated, partly due to gas content inherent in high-pressure die casting. Confirm with your caster.