Cast Aluminum vs. Die Cast Aluminum: The Differences Explained

Cast aluminum” generally refers to aluminum castings made through the casting process, while “die-cast aluminum” refers to aluminum castings made through high-pressure die-casting. The primary difference between the two is the casting process used.

What’s The Difference Between Cast Aluminum And Die Cast Aluminum

In the casting process, methods such as sand casting, dewaxing casting, gravity casting, low-pressure casting, ceramic mold casting, and gypsum mold casting are used. The die casting process, on the other hand, is a type of high-pressure die casting produced using a cold chamber die casting machine.

The aluminum grades used in the two processes are different, with ZL representing cast aluminum alloys in China’s national standard GB and YL representing cast aluminum alloys.

Cast aluminum castings can typically be strengthened through heat treatment, with T6 heat treatment being the most common method. However, die castings are not suitable for T6 heat treatment due to the large amount of gas densely distributed within them. This is because the temperature of T6 heat treatment is close to the melting point of aluminum alloys and the gas in the die casting will expand and be forced out of the casting surface, leading to surface damage and rendering the casting unusable.

Due to the dot protrusion after the gas runs out, the appearance of the casting is seriously damaged and cannot be used.

Aluminum alloy gravity casting and aluminum alloy low-pressure casting belong to the metal mold casting process and are used to produce aluminum castings. The molds are made of hot work die steel, such as H13.

These casting processes can produce the same brand of cast aluminum alloy, with similar pouring temperature and mold opening time, as well as compactness, strength, and other mechanical properties of the aluminum castings.

However, there are still differences between aluminum alloy gravity casting and aluminum alloy low-pressure casting in terms of forming principle, aluminum casting structure, labor intensity, batch number, development time, etc., as shown in the figure below.

 Forming principleAluminum casting structurelabour intensityMinimum batchDevelopment timeMold cost
Aluminum alloy gravity castingUsing gravityComplex and diversehigh100shortless
Aluminum alloy low pressure castingUsing air pressuresinglecommonly500longHigher

According to the comparison shown above, aluminum alloy gravity casting is ideal for producing products with multiple varieties, small batch sizes, short development cycles, and high quality requirements, while aluminum alloy low-pressure casting is ideal for products with large batch sizes, thin walls, and structures that are suitable for the low-pressure casting process.

The long development cycle of the latter benefits the improvement of production technology throughout the manufacturing process.

A typical product produced through aluminum alloy low-pressure casting is an automobile wheel rim. Its structure is well-suited for the low-pressure casting process and the high volume of production allows sufficient time to improve production technology.

In contrast, typical products produced through aluminum alloy gravity casting are industrial robot castings. These aluminum castings require small production batches, high product quality, and a short development cycle. The aim is to produce high-quality aluminum castings without any pores or sand holes in a very short time.

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