Aluminum comes in several forms, and they all stand out for versatility, lightweight, and corrosion resistance. However, each form has a unique advantage over the other, and when considering cast aluminum vs aluminum, choosing one can be complex.
Cast aluminum is made by melting and pouring the metal into molds, allowing manufacturers to create complex aluminum parts. On the other hand, aluminum/wrought aluminum undergoes mechanical processes like rolling, forging, or extrusion, which makes it stronger and more ductile.
Choosing between both aluminum forms depends on the project. However, in terms of which is better, this article explores their properties, weighing their advantages and disadvantages to understand better which form of aluminum suits different industrial needs.
What is Cast Aluminium?
Cast aluminum refers to aluminum alloys made using metal casting techniques like die casting, sand casting, or permanent mold casting. The general template involves melting and pouring the molten aluminum alloys into molds and allowing them to solidify into the pre-designed shapes and designs.
Cast aluminum alloys often contain other elements like silicon, magnesium, or copper, which improve their castability and mechanical properties. The metal casting technique can also affect the final properties of the cast aluminum.
Characteristics of Cast Aluminium
- Like all aluminum, cast aluminum is lightweight
- Cast aluminum alloys, especially those containing silicon, have high corrosion resistance.
- Metal casting allows for complex shapes, including intricate internal geometries.
- Cast aluminum is strong, although it is weaker than wrought aluminum.
What is Wrought Aluminium?
Wrought aluminum refers to aluminum that has been mechanically processed through methods such as rolling, forging, extrusion, or drawing, which compresses the material and improves its structural integrity.
Wrought aluminum is often preferred for applications requiring strength and durability. The mechanical working process reduces internal defects that can form during casting, such as voids or porosity. As a result, wrought aluminum typically exhibits superior mechanical properties compared to its cast counterpart.
Characteristics of Wrought Aluminum
- Wrought aluminum is stronger than cast aluminum due to the absence of casting-related imperfections.
- The mechanical processes used to shape wrought aluminum give it greater flexibility, allowing it to bend without breaking.
- Wrought aluminum alloys resist cracking and breaking under repeated stress.
- Wrought aluminum is better suited for simpler shapes that require high strength.
Is Cast Aluminium Better Than Aluminium?
Choosing between cast aluminum vs aluminum depends on several factors, including mechanical properties, design flexibility, manufacturing costs, and environmental factors.
Mechanical Properties: Strength, Ductility, and Durability
Cast aluminum has lower ductility and mechanical strength than wrought aluminum due to the formation of micro-voids or imperfections during metal casting. The solidification of molten aluminum in molds can lead to porosity or internal flaws, which weaken the material.
On the other hand, wrought aluminum is mechanically formed through processes like rolling, extrusion, or forging. These processes compress the material, eliminating internal defects and increasing the toughness and fatigue resistance.
Verdict: In terms of mechanical properties such as strength, ductility, and durability, wrought aluminum alloys (e.g., 6061 and 7075) are better because they exhibit higher strength-to-weight ratios than cast aluminum.
Design Flexibility and Complexity
A primary advantage of cast aluminum over aluminum is its design flexibility. Metal casting allows for producing intricate shapes, including complex geometries, thin walls, and hollow structures. In contrast, wrought aluminum is more difficult to shape into elaborate forms, which is evident in its simplicity. However, wrought aluminum offers better performance for applications where strength and durability are more important than design intricacy.
Verdict: Cast aluminum leads in terms of design flexibility and complexity of final parts. As a result, it is suitable for high-design complexity applications such as engine components, decorative items, and automotive parts.
Corrosion Resistance
Both cast and wrought aluminum offer excellent corrosion resistance, which is one of aluminum’s defining characteristics. However, cast aluminum containing other alloying elements has better corrosion resistance.
Cast aluminum is ideal for marine and outdoor environments. Cast aluminum can also undergo anodizing and powder coating for surface finishing, resulting in a smooth, corrosion-resistant finish.
Verdict: Cast aluminum and its other alloying elements can resist corrosion better than wrought aluminum.
Manufacturing Processes and Costs
The manufacturing costs for cast aluminum are generally lower due to the high scalability of metal casting processes. Techniques like die casting and sand casting, allow for mass production of components with minimal material waste and reduced labor costs.
On the other hand, manufacturing wrought aluminum using processes like extrusion, rolling, and forging requires more energy input and machines. This results in higher costs, especially for small or custom production runs.
Cast aluminum is also subjected to other manufacturing processes, the most prominent of which is CNC machining. Wrought aluminum, on the other hand, is more compatible with sheet metal fabrication processes.
Verdict: Cast aluminum has a lower manufacturing cost due to the metal casting process, which makes it better for large-scale production runs where cost-efficiency is a priority.
Surface Properties
The surface properties of the cast aluminum depend on the metal casting techniques. Metal casting services often recommend die casting for a smooth surface and sand casting for a “sand” or matte finish. On the other hand, wrought aluminum has a smooth surface finish.
Applications and Industry Preferences
Cast aluminum is suitable for industries that require complex shapes and intricate designs. Common aluminum cast projects include automotive parts, machinery components, consumer goods, and decorative items.
Wrought aluminum is suitable for projects that require a high strength-to-weight ratio. Typical applications include aerospace structures, load-bearing components, building materials, and medical devices.
Cast Aluminum vs Aluminum
| Feature | Cast Aluminum | Wrought Aluminum |
| Strength | Lower due to potential casting imperfections | Higher due to work-hardening processes |
| Ductility | Less malleable, prone to brittleness in some alloys | More ductile and better for bending and shaping |
| Design Flexibility | Excellent for intricate shapes and complex geometries | Limited to simpler forms |
| Corrosion Resistance | High, particularly with silicon-rich alloys | High, but may require additional surface treatment |
| Cost | Lower due to efficient mass production | Higher due to energy-intensive manufacturing |
| Surface Finishing | Smooth and customizable for decorative purposes | Often requires additional finishing for smoothness |
| Applications | Ideal for automotive, consumer products, and machinery | Preferred for aerospace, structural, and medical components |
| Weight | Lightweight, but generally heavier than high-strength wrought alloys | Lightweight with superior strength-to-weight ratio |
Conclusion
Answering whether cast aluminum is better than wrought aluminum requires considering the project’s specific requirements. Cast aluminum is better for projects that require complex designs, while wrought aluminum excels in strength, durability, and ductility.
In conclusion, select the best form of aluminum, cast or wrought aluminum, by checking the one that aligns better with project-specific performance and long-term durability.