Which aluminum alloys are most common in automotive die casting?

A380 and ADC12/A383 families are among the common choices for general automotive high-pressure die-cast housings, covers, brackets, and modules. A360, A413, and AlSi12-type alloys are also screened where their filling, corrosion, pressure, thermal, or machining balance fits. A356, AlSi7Mg, and AlSi10Mg families appear in automotive castings through gravity, low-pressure, vacuum-assisted, structural, additive, or other routes. The exact process and condition must be stated; these grades are not interchangeable.

Define the component before the alloy

State whether the part is a transmission case, engine cover, pump or valve body, motor housing, inverter enclosure, battery structure, body node, bracket, heat sink, steering or suspension component, interior hardware, or service part. Add load, fatigue, crash, vibration, pressure, temperature, fluid, thermal, electrical, corrosion, joining, machining, finish, recycling, and product-safety requirements.

Material selection follows the dominant failures. A thin electronics enclosure prioritizes filling, dimensions, shielding, thermal paths, and coating. A pressure body adds boundary integrity and machining breakout. A structural node adds ductility, crash, fatigue, joints, repair, and local-defect controls. No alloy name approves all three.

Screen general-purpose HPDC alloys

A380 is widely encountered in North American die casting, and ADC12/A383-type grades are common in other supply chains. They are often selected for a practical balance of filling, mechanical behavior, machining, finish, availability, and cost in repeat production. Chemistry and regional specifications differ, so “equivalent” substitution requires customer engineering approval.

These families can fit cases, covers, brackets, appliance-like vehicle modules, and other integrated parts when finished requirements are demonstrated. They should not be described as automatically structural or pressure tight. Gate, vent, vacuum, section, porosity, oxide films, machining, and tests determine the part result.

Screen A360, A413, and AlSi12 by function

A360 may be considered where corrosion response, filling, and pressure-related behavior are important, but actual casting integrity and finish system remain project-specific. A413 and AlSi12-type high-silicon alloys may be considered for filling, pressure boundaries, wear, thermal expansion, or selected thin geometry, subject to exact chemistry and route.

Higher silicon can affect machining, ductility, anodized appearance, joining, and wear. Define seal lands, threads, bores, thermal interfaces, cosmetic surfaces, coating, and adhesive or weld requirements before selecting. A nominal alloy advantage can be lost if downstream operations or assembly are incompatible.

Separate A356 and AlSi10Mg from conventional HPDC assumptions

A356, AlSi7Mg, and AlSi10Mg-type alloys can offer useful strength, ductility, fatigue, corrosion, joining, or heat-treatment directions in suitable casting processes and conditions. They are common references for wheels, suspension, structural castings, body nodes, and other demanding components, but the route may be gravity, low pressure, squeeze, vacuum-assisted, semi-solid, or another controlled process.

Do not quote a T6 or additive-manufacturing property against a conventional high-pressure die casting. Entrapped gas can affect thermal-treatment feasibility; section and solidification affect local properties. Require route-specific chemistry, condition, porosity, material specimens, heat-treatment, dimensions, joining, and component test evidence.

Use a route-aware screening table

Control material and melt identity

Specify governing standard, grade, chemistry, approved alternatives, recycled-content requirements where applicable, ingot and return policy, melt handling, sampling, condition, and traceability. Incoming certificates do not prove poured chemistry when returns, holding, transfer, or contamination can change the melt. Define sampling and reaction.

Regional equivalents need clause-level comparison, not a sales statement. Differences in copper, iron, magnesium, zinc, silicon, restricted elements, and impurities can affect castability, mechanical behavior, corrosion, machining, joining, and finish. Record the approved material on drawing, purchase order, control plan, and PPAP evidence.

Verify the finished part, not only a test bar

Use published properties to screen when grade, route, condition, section, specimen source, orientation, temperature, and method match. Separately cast bars may not reproduce a gate, thin rib, heavy boss, machined seal, or oxide film. Cut specimens also represent only their sampled zones.

Select chemistry, hardness, tensile, microstructure, fatigue, leak, pressure, corrosion, thermal, electrical, dimensional, joining, and component tests by the product risk. Define specimen source and acceptance. No single material row proves crash, durability, pressure integrity, or corrosion in the assembled vehicle.

What buyers should request

Provide the controlled design, function, failure consequence, loads and environment, exact material or property targets, allowed casting routes, demand, special characteristics, internal-integrity zones, machining, joining, heat treatment, finish, tests, APQP/PPAP, traceability, capacity, and change requirements. Ask the supplier to identify exceptions before tooling.

The aluminum die-casting supplier should return exact grade, standard, route, condition, approved alternatives, melt plan, tool and cavity concept, property basis, porosity controls, downstream work, validation, sub-tiers, and open risks. A common alloy is only a starting point; the right alloy is the approved one that remains suitable after casting, machining, joining, coating, and vehicle testing.