Aluminum casting alloys (or aluminium alloys; see spelling differences) are alloys in which aluminum (Al) is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon, tin and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories heat-treatable and non-heat-treatable. About 85% of aluminum is used for wrought products, for example rolled plate, foils and extrusions. Cast aluminum alloys yield cost-effective products due to the low melting point, although they generally have lower tensile strengths than wrought alloys. The most important cast aluminum alloy system is Al–Si, where the high levels of silicon (4.0–13%) contribute to give good casting characteristics. Aluminum alloys are widely used in engineering structures and components where light weight or corrosion resistance is required.
Aluminum castings are lightweight and able to withstand the highest operating temperatures of all die cast alloys. Aluminum’s strength, corrosion resistance, and heat dissipating properties offer mechanical designers significant advantages. And our proprietary Thin Wall Aluminum Technology has made aluminum die casting an option for even more applications.
Interested in Learning More About the Die Casting Process?
Check out our other die casting resources here. One of the most significant benefits of aluminum die casting is that it creates lighter parts—with more surface finishing options than other die cast alloys. Aluminum can also withstand the highest operating temperatures of all the die cast alloys. Moreover, cast aluminum is versatile, corrosion resistant; it retains high dimensional stability with thin walls and can be used in almost any industry.
Aluminum Casting Alloy Applications
Aluminum castings improve automotive fuel efficiency by contributing to weight saving requirements. Aluminum is used in a broad range of networking and infrastructure equipment in the telecom and computing industries because RF filter boxes and housings require heat dissipation. In handheld devices, aluminum castings provide EMI/RFI shielding, rigidity, and durability with minimal weight. Because of aluminum’s excellent electrical performance and shielding properties, even in high-temperature environments, die cast aluminum is ideal for electronic connectors and housings.
There is very little functional difference between primary (extracted or pure) and secondary (recycled) aluminum when it refers to die casting. Secondary aluminum alloys are derived from mixing and melting pure aluminum with other materials such as magnesium, iron, and copper. The use of pure aluminum in casting is quite rare due to the cost of extraction. The ease of use in die casting combined with lighter weight and durability make aluminum alloys a top choice for designers from nearly any industry.
Secondary aluminum casting alloys are more economical to produce than primary aluminum because it only requires 5 percent as much energy to produce. Most of the energy consumption in aluminum die casting is used to heat and re-melt the metal during fabrication.