A356 (Al-7Si-0.25Cu-0.2Fe-0.4Mg) and A319 (Al-6Si-3Cu-1Fe-1Zn) remain the two gravity-cast workhorses behind most industrial castings, while A380 (Al-8.5Si-3.5Cu-3Zn) and A383 (Al-10.5Si-2.5Cu-3Zn) cover the majority of high-pressure die-cast housings and covers [S4].
Specifying engineers usually choose on three axes: silicon content drives fluidity and wear resistance, copper raises strength at the cost of corrosion, and magnesium enables age-hardening response (T6/T7) for structural duty [S4].
Gravity-Cast Family: A356 and A319
A356 is one of two gravity-cast aluminum alloys, with the Al-7Si-0.25Cu-0.2Fe-0.4Mg chemistry, that account for most industrial applications, per the 'Cast Aluminum Alloy' overview on ScienceDirect Topics [S4]. Typical applications are automotive wheels, suspension knuckles, pump housings, and high-strength brackets where elongation and pressure tightness matter more than peak hardness.
A319 trades ductility for higher strength by lifting Cu to about 3% and adding 1% Fe and 1% Zn (Al-6Si-3Cu-1Fe-1Zn); it is the alloy of choice for engine blocks, cylinder heads, and gearbox cases that must handle elevated temperature and cyclic load without T6 treatment [S4]. When a casting must pass ASTM B686/B686M high-strength requirements for defense or aerospace structural parts, A356-T6 and A357-T6 are the most frequently qualified grades [S6].
High-Pressure Die-Cast Family: A380, A383, A384
For high-pressure die casting, the Aluminum Association 380-series is the default: A380 (Al-8.5Si-3.5Cu-3Zn) flows into thin walls and is used for non-structural covers, gear cases, motor housings, and telecom enclosures; A383 (Al-10.5Si-2.5Cu-3Zn) is a higher-strength variant favored where the die-cast part carries real structural load [S4]. Chinese die-casting suppliers such as Hechang Technology (Dongguan) Co., Ltd. routinely machine these alloys into electric motor products, communication-system components, power-tool bodies, and advanced home-appliance parts, with product lines explicitly listed across those industrial metal-part categories [S1].
Real-world pricing for finished die-cast aluminum components in 2026 sits in a wide band: a custom high-precision die-cast aluminum transmission housing for automotive use is listed at US$8,000–US$20,000 per set on Made-in-China.com, with 1-set MOQ and full customization available [S2]. That listing uses the designation "ap031" and confirms a high-precision tooling route typical for HPDC A380/A383 housings, not gravity-cast A356.
Secondary Cast Alloys and Specialty Grades
Beyond the four "big-volume" grades, several specialty cast alloys solve specific problems. A201 (Al-4.6Cu-0.3Mn-0.25Mg-0.2Ti) is a high-strength, room-temperature-aging sand/permanent-mold casting alloy used where tensile strength and fatigue resistance dominate, at the cost of castability. A390 (Al-17Si-4.5Cu-0.5Mg) is the standard wear-resistant grade: with ~17% Si it forms primary silicon particles that resist abrasion, so it goes into engine pistons, cylinder liners, and pump impellers [S4].
For higher-temperature structural parts, AMS-spec wrought equivalents like 2219-T8511 (Al-6.3Cu-0.30Mn-0.18Zr-0.10V-0.06Ti) cover structural service up to 500 °F (260 °C) per SAE AMS4162E-2014, although that specification covers extrusions, not castings — the point is that the same Cu-rich chemistry family (2xxx) reappears in cast form when elevated-temperature strength is required [S5].
Surface Treatment and Joining Considerations
Surface engineering of cast aluminum has moved well beyond anodizing. A 2021 ScienceDirect study on A356 used pulsed-laser hatch patterning plus nitriding (PLHN) in liquid-nitrogen atmosphere, varying laser wavelength between 532 nm and 1064 nm and nitrogen flow between 5 and 35 L/min, to build a surface nitride layer that hardens the cast skin [S3]. The same logic shows up in production: HPDC A380/A383 housings are typically machined, then either anodized, powder-coated, or chromate-conversion-coated depending on whether the part will see marine atmosphere, automotive underbody, or indoor telecom-rack duty [S1].
Joining is the other constraint engineers forget: high-Cu cast alloys (A319, A380, A390) are weldable but lose strength in the HAZ unless re-heat-treated; A356 and A357 are far more weld-friendly. For structural chassis and battery-tray applications on light vehicles, this is one reason the automotive OEM stack is moving away from high-Cu A380 toward low-Cu A356/Castasil-37 type chemistries that can be welded or friction-stir-welded without post-weld solution treatment.
Selection Criteria and Process Fit
The cleanest way to pick a cast aluminum alloy is to map the casting process against the duty cycle, not the other way around. Sand and permanent-mold gravity casting favor A356/A319, where heat treatment and weldability matter; high-pressure die casting overwhelmingly uses A380/A383 because their higher Si (8.5–10.5%) keeps the alloy fluid through long, thin die-cavity paths [S4].
For engineers comparing the main options, four criteria line them up: tensile/yield strength favors Cu-rich A319 and A380; ductility and weldability favor A356; wear and elevated-temperature stability favor A390; and pressure-tightness after T6 favors A356-T6 and A357-T6 [S4][S6]. Reference the cast aluminum alloy overview for the full property comparison, and the die-casting machine reference for the equipment side of the process.
Standards and Sourcing Signals
ASTM B686/B686M-2010 governs high-strength aluminum-alloy castings, covering alloys such as A356.0, A357.0, A201.0, and D357.0 in its Table 1, and is the standard defense/aerospace buyers ask for when a structural cast part enters qualification [S6]. At the sourcing level, China's HPDC capacity is now broad enough that automotive transmission housings, power-tool bodies, and home-appliance covers ship as stock or near-stock items: a die-cast aluminum transmission housing listing sits at US$8,000–US$20,000 per set with 1-set MOQ and customization [S2], while general casting suppliers in the same corridor list HPDC lines spanning communication, automotive, and new-energy categories [S1].
Two trackable signals to watch in the second half of 2026: (1) auto-OEM moves to lower-Cu, weldable Al-Si-Mg die-cast chemistries for battery enclosures and structural underbodies, which would shift HPDC demand away from A380/A383 and toward A356/A357 variants cast in HPDC presses; (2) wider use of laser-assisted surface nitriding on A356-type castings, building on the 5–35 L/min N₂ flow / 532–1064 nm laser process window already published for A356 [S3]. Related reference: Aluminum Sheet Suppliers 2026: China Capacity, Alloy Bands, and Sourcing Map and Metal Stamping Part Types, Spec Bands and 2026 Industrial Use Map.
The underlying component specifications are covered under cast iron.