Which Aluminum Alloys Are Used in High Pressure Die Casting?
Common alloys for conventional high pressure aluminum die casting include A380, A360, A413 and grades described as A383 or ADC12 in their respective designation systems. A380 is a frequent general-purpose starting point, A360 is often reviewed where its corrosion behavior or other specified properties matter, and A413 is associated with high fluidity. A383 and ADC12 are used for manufacturable production castings, but their names must not be treated as automatic equivalents.
The correct alloy is the grade that meets the drawing's chemical, functional, finishing and commercial requirements through the selected casting route. Buyers should approve a governing specification and material condition, not simply select a familiar name from an aluminum die-casting alloy list.
Compare the common HPDC options
A380 is widely considered for housings, covers, brackets and other general production parts because it provides a practical combination of castability, mechanical performance and machining response. It is not automatically suitable for every corrosion, ductility, thermal or cosmetic requirement. Confirm the exact specification and test the finished condition that matters.
A360 may be evaluated where corrosion behavior, strength at service conditions or another documented property justifies it. Its casting behavior and process implications must be reviewed with the supplier rather than inferred from one favorable property. Coating, exposure and geometry remain part of the corrosion system.
A413 is known for fluidity and may help difficult fill or pressure-containing designs. Fluidity cannot repair an unsuitable gate, blocked vent, abrupt section change or poor thermal plan. Pressure integrity still requires location-specific porosity control and a defined leak test after relevant machining.
A383 and ADC12 occur in different standards and supply chains. Their chemistry and permitted limits must be checked against the controlled specification. If a supplier proposes one as a substitute for the other, require a comparison of composition, material condition, casting behavior, properties, machining and finish, followed by formal buyer approval.
Alloy designation | Useful selection direction | Do not assume |
|---|---|---|
A380 | General HPDC housings, brackets and covers needing a balanced route | That common use proves the required property or finish |
A360 | Projects where its specified corrosion or performance profile is relevant | That alloy choice alone guarantees outdoor life |
A413 | Difficult fill or pressure-related parts where fluidity is valuable | That good flow guarantees leak-free castings |
A383 / ADC12 | Production HPDC after the exact standard and chemistry are agreed | That the designations are interchangeable without review |
Do not mix casting routes by alloy name
A356 is commonly associated with gravity or low-pressure casting and with heat-treated conditions such as T6. It should not appear as a routine conventional HPDC option merely because it is an aluminum casting alloy. If the drawing calls for A356 or a heat-treated property set, first define the casting route, material temper, specimen basis and validation plan.
Conventional HPDC can trap gas during rapid filling. Solution heat treatment may expand that gas and blister a casting. Welding can also be sensitive to internal gas, oxide films, alloy chemistry and surface contamination. Vacuum-assisted or specialized structural HPDC may change the risk, but only representative process evidence can qualify the proposed route.
Select for the finished part, not one property
Start with loads, service temperature, corrosion medium, thermal needs, pressure boundary and expected life. Then consider fill distance, section thickness, porosity-sensitive zones, machining and finish. Published material values may come from separate specimens or conditions that do not represent a thin wall, a thick boss, a pore-sensitive machined surface or the final coated casting.
For strength or ductility requirements, state the applicable standard, sampling route and condition. Decide whether testing uses separately cast specimens, specimens cut from a casting, or a functional part test; they are not interchangeable. For thermal performance, validate the actual heat path, interface flatness, contact material and coating rather than selecting an alloy from conductivity alone.
Include machining and finish in alloy approval
Alloy chemistry influences tool wear, chip behavior, burrs, surface response and coating preparation. Mark machining depth on sealing faces and ports because cutting can expose subsurface porosity. Approve the alloy with the actual CNC route where leakage, thread integrity or surface appearance matters.
Die-cast alloys with substantial silicon or copper may not anodize with the color uniformity of wrought aluminum. Powder coating, paint and conversion coatings also rely on cleaning, pretreatment and casting-surface condition. Use representative production-route coupons or parts to establish a visual range and performance test. An alloy change after finish approval may require renewed trials.
Lock the RFQ and material records
The RFQ should name the alloy, designation system, specification edition and any permitted alternatives. State certificate and traceability needs, mechanical or chemical verification, service exposure, machining, coating and restricted substances. Ask the supplier to disclose its melt-control method and any assumptions about return material. The broader buyer alloy comparison can support review, but the released drawing and purchase specification must control.
Approve substitutions only through documented change control. Compare chemistry and condition first, then determine which casting trials, dimensions, porosity checks, machining, finish or functional tests must be repeated. The lowest raw-metal quote is not a saving when an unreviewed grade shifts yield, tool behavior or final performance.
