Cast aluminum and die cast aluminum refer to materials used in different aluminum alloy casting processes. Cast aluminum is usually used in gravity casting, sand casting, or low-pressure casting processes. Due to process limitations, the finished product has lower strength and precision. Die cast aluminum is usually used in high-pressure die casting processes. After proper process control, the finished product has better stability and precision than sand or low-pressure casting products.
This article will introduce the definitions of cast aluminum and die cast aluminum, material properties, usage conditions, common grades, common applications, main differences, and the advantages of CEX Casting. Please read on to help you choose the most suitable cast aluminum material for your next project.
Die Cast Aluminum
Definition
Die cast aluminum is a type of aluminum alloy material specially used for high-pressure die casting.
It uses aluminum as the matrix element and usually contains a high proportion of silicon (generally 7%–12%).
Depending on the alloy system, copper, magnesium, zinc, iron, and other elements can also be added.
Aluminum Die Casting
Material Properties
Die cast aluminum materials usually contain alloying elements such as silicon and copper, and have good fluidity and thermal cracking resistance.
Under rapid solidification conditions, its structure is fine and uniform, and the grains are fine.
Due to its dense structure and uniform distribution, the material exhibits excellent strength, hardness, and dimensional stability.
Conditions of Use
Die cast aluminum materials are suitable for high-pressure, rapid solidification molding environments and need to be used with special die casting equipment and steel die casting molds.
Its performance depends on rapid cooling and die casting die precision, and requires high process control.
The material itself is not suitable for welding and heat treatment, and the product structure and functional requirements should be determined in advance during the design stage.
Common Die Cast Aluminum Grades
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A380: Balanced performance, strong fluidity, dimensional stability, and thermal cracking resistance, suitable for structural parts.
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A383 (ADC12): More suitable for die casting parts with complex shapes or thin-walled structures than A380, with better fluidity.
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A360: Mechanical properties and corrosion resistance are better than A380, suitable for high environmental tolerance.
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AlSi9Cu3: With high strength and good machinability, suitable for die casting products with extensive post-machining and high precision requirements.
Common Applications
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Automotive Industry: transmission housing, motor bracket, gearbox, motor housing, and other structural and functional parts.
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Consumer Electronics: laptop frames, mobile phone frames, camera housings, and other appearance and structurally integrated parts.
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Electrical and Lighting: LED light housings, electronic device enclosures, power supply covers, circuit board enclosures, light fixtures, and heat sinks.
Cast Aluminum
Definition
Cast aluminum refers to a type of aluminum alloy material specially used for gravity casting, sand casting, or low-pressure casting processes. It is based on aluminum and usually contains 6%-12% silicon.
Depending on the grade, it contains a certain proportion of magnesium, copper, and other elements to meet different mechanical properties and processing requirements.
Aluminum Sand Casting
Material Properties
Cast aluminum alloys have a high silicon content and have excellent thermal conductivity and corrosion resistance; magnesium-containing grades such as A356 and AlSi10Mg have good processability and weldability.
This type of material is often used in traditional casting processes with slow cooling and low pressure, resulting in limited performance.
However, the material itself is not weak and can show higher strength and density in advanced die casting processes such as squeeze casting.
Conditions of Use
Cast aluminum materials are suitable for casting processes under low pressure or no pressure, with low requirements for mold rigidity, and are suitable for molding large-sized and thick-walled parts.
The material is stable under slow cooling conditions, has low dependence on equipment and processes, and is suitable for small and medium-sized batches or customized production.
Common Cast Aaluminum Grades
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A356 (AlSi7Mg0.3): strong versatility, good balance of casting performance and strength, suitable for sand molds and low-pressure casting.
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AlSi12: good fluidity and wear resistance, suitable for thin-walled structural parts or complex appearance parts.
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AlSi10Mg: high strength and good ductility, suitable for structural parts or parts requiring post-machining.
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AlSi7Mg: low thermal cracking tendency and stable organization, often used for large shells and industrial castings.
Common Applications
Cast aluminum is mainly used for parts with low precision requirements, simple structure, or large volume:
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Automotive Industry: engine block, intake manifold, chassis bracket, etc.
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Industrial Equipment: large equipment housing, foundation base, support structure, etc.
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Outdoor and Marine: light poles, railings, decorative parts, marine corrosion-resistant parts, etc.
Key Differences Between Cast Aluminum and Die Cast Aluminum
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Property Categories |
Cast Aluminum (paired with Gravity / Low-Pressure / Sand Casting) | Die Cast Aluminum (paired with High-Pressure Die Casting) |
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Alloy System Composition |
Al-Si based, often with magnesium (e.g., A356, AlSi10Mg) | Al-Si based, often with copper, magnesium, zinc (e.g., A380, AlSi9Cu3) |
| Typical Silicon Content | Generally 6%–12%, some as high as 13% |
Typically 7%–12%, precisely controlled for flow and demolding |
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Thermal Conductivity |
Relatively high; suitable for heat-dissipating structures | Slightly lower; some alloys are optimized for thermal performance |
| Corrosion Resistance | Naturally good; suitable for outdoor and humid environments |
Varies by copper content; can be improved by alloy adjustment |
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Weldability |
Excellent for Mg-containing alloys (e.g., A356, AlSi10Mg) | Poor due to high copper; better for mechanical fastening |
| Machinability | Good; supports milling, tapping, and welding |
Easy to machine, but not suitable for welding |
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Material Property* |
Stable at the material level, but casting processes affect the final part quality | Highly consistent when paired with the die casting process; ideal for complex-shaped parts |
| Common Grades | A356, AlSi12, AlSi10Mg, AlSi7Mg |
A380, A383, A360, AlSi9Cu3 |
*Note: Material properties such as strength, density, and porosity rate are greatly affected by the casting process. The table shows the material properties of the material under a typical casting process.
Advantages of CEX Casting
Full Coverage of Aluminum Alloy Materials
CEX Casting is familiar with mainstream die cast aluminum and cast aluminum alloys, including A380, A383, A360, AlSi9Cu3, A356, AlSi10Mg, AlSi12, AlSi7Mg, etc.
We can accurately recommend suitable materials to customers based on indicators such as strength, thermal conductivity, and machinability.
Raw Material Quality Control
Equipped with a spectrometer, the raw materials are tested for chemical composition before entering the factory to ensure that the content of each alloy element meets the standard range.
Equipped with a tensile testing machine, some key materials can be tensile tested to verify whether their mechanical properties meet the requirements.
Squeeze Casting Process
Advanced Process
Cast aluminum materials (such as A356, AlSi10Mg) are prone to defects such as coarse finished grains, shrinkage, and pores in traditional gravity or low-pressure casting, resulting in lower mechanical properties than aluminium die casting components.
This makes many people mistakenly believe that cast aluminum is not as good as die cast aluminum. The root cause lies in the molding process.
CEX Casting uses advanced squeeze casting technology to apply high pressure during the solidification process of the alloy to densify the casting and significantly improve the mechanical properties.
High Mechanical Strength
The tensile strength of aluminum parts formed by squeeze casting can reach 320 MPa, and the yield strength can reach 260MPa, which is far higher than conventional aluminium alloy die casting parts.
At the same time, the material has almost no pores inside, which is suitable for structural parts with extremely high requirements for strength, safety, and sealing.
Request the Squeeze Casting Case Study
Conclusion
Cast aluminum and die cast aluminum are materials used in different aluminum alloy casting processes. Both have their advantages in strength, precision, and output requirements.
As a professional aluminum die casting manufacturer, CEX Casting provides high-quality one-stop aluminium die casting and squeeze casting solutions.
Welcome to contact us to get customized solutions for your next aluminum alloy casting project.