01Three grades that are not interchangeable
When a buyer asks for an aluminum die-cast part, the alloy line on the drawing often looks simple: ADC12, A380, or A360. In production, it is not. The alloy affects filling, soldering, porosity risk, machining, corrosion, temperature capability, surface finishing, and process cost. The most expensive mistake is to treat the three grades as interchangeable because they have similar names, similar density, or similar catalogue strength. They are different alloy systems and different designation systems. A380 and A360 are North American Aluminum Association designations commonly used with NADCA guidance. ADC12 is a JIS designation widely used in Asian die-casting supply chains. A supplier can often cast all three, but the die design, shot profile, metal control, inspection plan, and acceptance criteria should not be copied from one alloy to another. The practical question is not “Which alloy has the highest tensile strength?” It is “Which alloy gives this geometry, service environment, and secondary process a repeatable cost and quality outcome?”
02What the alloy designation really controls
According to the 2024 NADCA Product Specification Standards, aluminum die-casting alloys are built mainly from silicon, copper, magnesium, iron, manganese, and zinc. Each element changes the alloy both independently and in combination with the others. Silicon supports fluidity and castability; copper generally increases strength and hardness but can reduce corrosion resistance; magnesium can improve strength and elevated-temperature performance; iron helps reduce soldering to the die but can increase brittle intermetallic phases when excessive. NADCA also notes a specific gravity of approximately 2.7 g/cm³. That low density supports lightweight housings, brackets, motor components, heat-management parts, and automotive structures. The decision must include the casting process and finished-part condition, not only ingot analysis.
03Composition comparison
The following ranges are useful for a first engineering comparison. Single values are maximum limits unless a range is shown. According to the JIS-style composition tables in the die-casting handbooks, ADC12 also controls manganese, nickel, tin, lead, and titanium at small percentages, with aluminum as the balance. The purchase specification should name the governing standard and full element limits. “ADC12 equivalent” is not a complete material specification. According to NADCA Table A-3-1, A380.0 contains more copper than A360.0, while A360.0 contains substantially more magnesium. A380 is usually selected for robust general production and balance; A360 is considered when corrosion resistance, ductility, or elevated-temperature strength matters more than easy filling. ADC12 may sit between them in a quotation, but it is not a formal one-to-one substitute.
| Alloy | Silicon (Si) | Copper (Cu) | Magnesium (Mg) | Iron (Fe) | Zinc (Zn) | Practical reading |
|---|---|---|---|---|---|---|
| ADC12 | 9.6–12.0% | 1.5–3.5% | ≤ 0.3% | ≤ 1.3% | ≤ 1.0% | 高硅 JIS 合金，着眼于流动性与通用压铸 / High-silicon JIS alloy aimed at fluidity and general-purpose die casting |
| A380.0 | 7.5–9.5% | 3.0–4.0% | ≤ 0.10%（E380 允许 0.30%）/ max. 0.10% (0.30% permitted for E380) | ≤ 1.3% | ≤ 3.0% | 北美通用合金，生产记录成熟 / General-purpose North American alloy with a strong production record |
| A360.0 | 9.0–10.0% | ≤ 0.6% | 0.40–0.60% | ≤ 1.3% | ≤ 0.5% | 高镁低铜，着眼于耐蚀与耐温 / Higher magnesium, low copper, for corrosion and temperature capability |
← Swipe sideways for all columns →
04Typical material performance
According to NADCA Table A-3-2, typical as-cast properties from separately die-cast specimens are shown in the table. These are typical reference values, not design minimums. NADCA states that the specimens are separately die cast, not cut from production castings. Production properties can vary with wall thickness, gate location, solidification, trapped gas, inclusions, heat history, and machining location. ADC12 should be evaluated with the same discipline. Reported values may be broadly comparable with general-purpose A380-class castings, but that is not permission to substitute alloys. For a load-bearing or pressure-containing part, approve the test method, coupon location, and minimum value for the production condition. NADCA's characteristic ratings add important context. A380 has a die-filling rating of 2 and A360 a rating of 3, where 1 is most desirable. A360 is rated better for corrosion resistance and strength at elevated temperature. A380 is described as the most widely cast aluminum die-casting alloy and as a good choice for general-purpose applications. NADCA describes A360 as more difficult to cast even though it offers higher corrosion resistance, superior elevated-temperature strength, and somewhat better ductility.
| Alloy | Ultimate tensile strength | Yield strength, 0.2% offset | Elongation | Density |
|---|---|---|---|---|
| A380.0 | 324 MPa | 159 MPa | 3.5% | 2.71 g/cm³ |
| A360.0 | 317 MPa | 165 MPa | 3.5% | 2.63 g/cm³ |
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05Why this matters in real production
The alloy changes the process window. ADC12's relatively high silicon can support flow into ribs, bosses, and thin sections, but tool wear, chip behavior, and surface response still depend on full chemistry and process. A380's production history can reduce start-up risk for a general housing, but its copper level may be a poor fit for corrosive service without a validated coating. A360 may suit corrosion or elevated temperature, but usually demands tighter control of metal temperature, die temperature, filling, and soldering. The effect becomes visible after machining. Die casting creates a relatively dense outer skin and a more defect-sensitive interior. If a bore, sealing face, or threaded feature is machined too deeply, it can expose porosity that was not visible on the as-cast surface. Alloy selection, gate and overflow design, vacuum performance, and machining allowance therefore need to be reviewed together. Surface treatment is also alloy-dependent. NADCA lists painting, powder coating, chromating, iridite, anodizing, and electrochemical finishing. “Black anodized aluminum” is incomplete unless the alloy, pretreatment, cosmetic zone, and acceptance sample are identified. Material availability and remelt practice also affect results. A chemistry certificate does not describe cleanliness, hydrogen control, melt filtration, or return-metal history. For a repeat program, approved alloy source and change control matter as much as the alloy name.
06From our experience: the order of questions, and what changing grade involves
In our experience three questions, asked in order, usually narrow the choice. First: will the part live in a damp, corrosive or hotter environment? If so, start by evaluating a low-copper, higher-magnesium alloy such as A360. Second: does it carry many bores and a lot of machining? If so, lean towards a general-purpose alloy with good machinability and a long production record, such as A380. Third: if neither applies and the part is thin-walled, complex, high-volume and cost-driven, ADC12 is often the starting point. The order matters — fixing the grade on cost first and discovering the service requirement afterwards leaves only a die change or a specification change. At quotation we state the standard and the grade actually being poured, rather than a vague “aluminum die casting”. When a customer asks to change grade mid-programme, our procedure is a new process sheet, a small trial lot with full dimensional and property verification, and a return to volume only after written approval from the customer. The three grades shrink by similar but not identical amounts, so running a different grade in the same die means a fresh first article with a full dimensional check; pour temperature, die temperature, shot velocity and hold time also have to be re-established rather than carried over.
07Common mistakes
Treating ADC12, A380, and A360 as interchangeable. Similar strength numbers do not mean identical filling, corrosion, temperature, or finishing behavior. Copying a catalogue property into the drawing as a guaranteed minimum. NADCA's values are typical values from separately cast specimens. A production requirement needs a defined test specimen and acceptance plan. Choosing the alloy before reviewing geometry. A long thin wall, deep machined pocket, pressure boundary, and cosmetic exterior create different risks. Review alloy, gating, vacuum, and machining stock as one system. Ignoring the service temperature and corrosion environment. A380 may be economical and easy to produce, but A360 or another alloy may be more appropriate for hot, humid, salt-spray, or chemically exposed service. Asking only for a mill certificate. It confirms chemistry, not porosity distribution, pressure tightness, dimensional capability, or coating performance. Letting the supplier change the alloy without written approval. “Equivalent” should mean equivalent against an agreed standard, composition range, process condition, and validation result, not simply a similar commercial label.
08Our typical approach
An experienced supplier starts from failure modes and total cost, then selects alloy and process together. The recommendation may be ADC12 for a general enclosure, A380 for a proven high-volume program, A360 for corrosion or heat exposure, or a different high-integrity alloy for welding or heat treatment. It should be justified by the drawing, service conditions, volume, and inspection plan. First, translate the requirement. We identify load direction, pressure or leak requirements, operating temperature, corrosion exposure, cosmetic zones, critical machined features, and annual volume before discussing price. Second, compare alloy-process combinations. We compare ADC12, A380, and A360 against filling length, wall transitions, die layout, expected porosity, machine size, surface finish, and machining depth. If the alloy on the drawing is not essential, we show the technical and commercial trade-off rather than making an unexplained substitution. Third, review the die and machining plan together. Gate location, overflow, vacuum, cooling, ejector layout, parting line, and machining datums are reviewed before steel is released. Critical bores and sealing faces receive a porosity-risk review, not only a dimensional review. Fourth, define validation on production-representative samples. We use first-article dimensional inspection, chemistry verification, mechanical test coupons where required, leak or pressure testing, and sectioning or X-ray for risk areas. The acceptance criteria are agreed before the first sample is judged. Fifth, control change. Alloy source, remelt ratio, shot profile, vacuum settings, die temperature, gate repair, heat treatment, and machining depth are treated as controlled changes. A stable process is part of the material specification in practice.
09Questions buyers should ask
1. Which standard governs the material: JIS for ADC12, Aluminum Association or ASTM for A380/A360, or a customer-specific specification? 2. What are the full chemical limits, including Fe, Mn, Zn, Ni, Sn, Pb, and “other” elements? 3. Is the quoted mechanical property typical data, a design minimum, or a tested minimum from this production condition? 4. Where will the test coupon be taken, and does it represent the thick and thin sections of the actual part? 5. What is the intended service temperature, corrosion environment, and surface-treatment system? 6. Which features will be machined, how much stock will be removed, and how will the supplier control porosity below the casting skin? 7. Is pressure tightness required? If yes, what test pressure, duration, orientation, and leak limit apply? 8. What alloy source, remelt practice, melt-cleaning controls, and change-notification process are included? 9. Which dimensions are cast dimensions and which are post-machined dimensions? What datum scheme will be used? 10. What evidence will be provided at first article and during serial production: chemistry, capability, leak results, X-ray or sectioning, and coating samples? These questions expose more risk than asking for the lowest material price and make quotations easier to compare.
SOURCES AND NOTE
- [1]North American Die Casting Association (NADCA). NADCA Product Specification Standards for Die Castings: Aluminum, Aluminum-MMC, Copper, Magnesium, Zinc and ZA Alloys, 12th edition, revised for 2024. Section 3, Aluminum Alloys, pp. 3-7 to 3-10; Tables A-3-1, A-3-2, and A-3-3.
- [2]North American Die Casting Association. 2021 NADCA Aluminum Die Casting Alloys (2021). Alloy selection, chemical composition, typical material properties, and die-casting characteristics.
- [3]吴春苗 主编.《压铸技术手册》. 广州: 广东科技出版社, 2006（ISBN 978-7-5359-3901-2）. 铝合金及 ADC12 / JIS 成分部分。
- [4]江昌勇 主编.《压铸成形工艺与模具设计》（第 2 版）. 工艺与模具设计背景。
This is a technical introduction and design guide, drawing on the sources listed above and on Jinxiong's many years of production practice. It is for reference only and is not a commitment for any specific project. For a specific project, the technical agreement between both parties governs.
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