Walk into any Asian die casting facility and the conversation is about ADC12. Walk into a North American one and it is all A380. Purchasing engineers routinely treat the two callouts as interchangeable on drawings, a reasonable simplification that hides measurable differences in fluidity, hot-tear resistance, machinability and corrosion behavior.
This guide compares the alloys properly, then extends the comparison to the two specialists (A360 and A413) that cover the applications the big two handle poorly.
1. Where Each Alloy Comes From
| Alloy | Standard | Regional Dominance |
|---|---|---|
| ADC12 | JIS H 5302 (Japanese) | Asia and global supply hubs |
| A380 | ASTM B85 / NADCA (North American) | North America; widely specified by US OEMs |
| A360 | ASTM B85 | Corrosion-critical applications worldwide |
| A413 | ASTM B85 | Thin-wall, pressure-tight, cosmetic-critical parts |
Both ADC12 and A380 are Al-Si-Cu alloys engineered for high-pressure die casting. The choice between them is largely a supply-chain decision (Asian foundries stock ADC12 ingots universally, while North American facilities default to A380) but the chemistry differences have real process consequences that matter at the margins.
2. Chemistry: The Devil Is in the Tolerances
| Element | ADC12 (JIS) | A380 (ASTM) |
|---|---|---|
| Silicon (Si) | 9.6 – 12.0% | 7.5 – 9.5% |
| Copper (Cu) | 1.5 – 3.5% | 3.0 – 4.0% |
| Iron (Fe) | ≤1.3% (typically held 0.8–1.0%) | ≤1.3% |
| Zinc (Zn) | ≤1.0% | ≤3.0% |
| Magnesium (Mg) | ≤0.3% | ≤0.10% |
Silicon is the fluidity element: it lowers melting point and lets molten metal navigate thin-walled sections without premature freezing. ADC12's higher silicon is why it fills complex geometry more reliably and resists hot tearing during rapid cooling.
Copper raises hardness and improves secondary machining characteristics, but it reduces natural corrosion resistance against harsh environments. A380's higher copper ceiling is part of why it machines with slightly better tool life, and part of why it is the wrong choice for coastal or chloride-exposed applications.
The recycling angle: A380's wider Cu and Zn ceilings tolerate a higher proportion of secondary (recycled) ingot in the melt charge, a real scrap-cost advantage that explains part of North America's historical preference. For programs requiring full traceability or corrosion-sensitive end use, the counter-move is to lock ADC12 or tighten the internal Cu control window rather than defaulting to the upper edge of the standard band.
3. Mechanical and Process Properties
| Metric | ADC12 | A380 |
|---|---|---|
| Tensile strength (UTS) | 240 – 310 MPa | 230 – 320 MPa |
| Yield strength | 140 – 170 MPa | 140 – 160 MPa |
| Elongation | 1 – 3.5% | 1 – 3.5% |
| Brinell hardness | 80 – 90 HB | 75 – 85 HB |
| Fluidity (spiral flow) | Favorable (high Si) | Moderate |
| Hot-tearing tendency | Lower | Moderate-to-higher |
| CNC tool wear | 10–15% faster (hard Si particles) | Better tool life |
| Chip formation (CNC) | Short, brittle chips | Long, continuous chips |
One honest caveat that applies to both alloys: neither delivers high elongation as-cast. That is an industry-wide reality of high-pressure die casting, not a design flaw of either grade. For structural load-bearing parts, design around the brittleness rather than expecting a heat treatment to fix it, standard HPDC parts cannot be safely T6-treated, because trapped injection gases expand aggressively at high temperatures and blister the surface.
4. The Specialists: A360 and A413
A360, The Corrosion Resister
A360 carries negligible copper. That single change delivers exceptional corrosion resistance and high pressure tightness, the reason marine hardware, outdoor telecom infrastructure and coastal-market products specify it. Where ADC12 or A380 would suffer salt-fog degradation, A360 holds. If your product lives outdoors near salt water, this is the alloy conversation to have before the tool is cut.
A413, The Thin-Wall Cosmetic
A413 pushes silicon to its near-eutectic maximum. The result is flawless cosmetic finishes and virtually zero solidification shrinkage. Engineers specify it for thin-walled parts where internal porosity would be catastrophic, hydraulic cylinders and pressure-containing components are the classic cases. The trade-off is lower mechanical strength, so it is a specialist, not a generalist.
5. Surface Treatment Behavior
- ADC12: its high silicon content makes conventional decorative anodizing produce uneven color and appearance. If a high-quality anodized finish is required, wrought aluminum (6061 and similar) is the better substrate, or plan on coating processes (powder coat, chromate conversion) instead of anodizing.
- A380: responds slightly better to post-casting chemical surface treatments; its balanced formulation allows consistent chromate conversion coating and reliable powder coat adhesion.
- Both: powder coating, wet painting, shot blasting, sand blasting, electroplating and chromate conversion are all standard and reliable.
6. Selection Logic
| Your Requirement | Recommended Alloy |
|---|---|
| Thin walls (<2.0 mm), complex geometry, high volume | ADC12, fluidity and hot-tear resistance win |
| Asian supply chain, cost-sensitive volume production | ADC12, universal ingot availability, ~5–10% material cost advantage |
| North American OEM drawing callout | A380, matching the spec avoids costly requalification |
| Maximum mechanical strength, thick sections | A380, higher Cu ceiling, more predictable shrinkage in heavy sections |
| Marine, coastal, outdoor corrosive exposure | A360, low copper, superior corrosion resistance |
| Thin-wall pressure-tight, cosmetic-critical | A413, near-zero shrinkage, excellent finish |
| Decorative anodizing required | None of the above, specify wrought 6061 or a coating process |
7. The Practical Answer
For most projects, ADC12 and A380 are functionally interchangeable, and the decision comes down to supply chain: manufacturing in Asia with thin-wall or complex geometry points to ADC12; supplying a North American OEM with a drawing callout points to A380. Switching between them rarely requires tooling changes, the shrinkage rates are nearly identical.
Where the choice genuinely matters is at the edges: corrosive environments (A360), thin-wall pressure boundaries (A413), and any part specified for decorative anodizing (neither, rethink the finish). Those decisions are cheap before the tool is cut and expensive after. If your part sits at one of those edges, flag it in the RFQ rather than assuming the default alloy will do.