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When strength matters, cast aluminum is often the ideal solution. But how strong is cast aluminum, really—and how does it compare to other metals or casting methods? In this article, we’ll break down the strength of cast aluminum, the factors that affect it, and how to choose the right alloy and casting process for your application.
What Is Cast Aluminum?
Cast aluminum refers to aluminum that has been melted and poured into a mold to take a specific shape. The most common processes used are:
- Gravity Die Casting – Ideal for structural parts with high dimensional stability.
- Low Pressure Die Casting – Used for more complex shapes requiring good surface finish.
- High Pressure Die Casting – Fast, precise, but typically lower ductility.
Each process affects the strength and mechanical properties of the finished part.
How Strong Is Cast Aluminum?
The strength of cast aluminum depends on several factors:
- The alloy used (e.g., A356, 6061, 319)
- The casting method
- Heat treatment (e.g., T5, T6 condition)
- Part design and wall thickness
Typical Tensile Strength Ranges (MPa):
| Alloy | Casting Method | Heat Treatment | Tensile Strength (MPa) |
|---|---|---|---|
| A356 | Gravity / Low Pressure | T6 | 250–320 |
| 319 | Gravity Cast | As-Cast | 140–180 |
| 6061 (Wrought) | Not Cast | T6 | 290–310 |
| 7075 (Wrought) | Not Cast | T6 | 500+ |
Note: 7075 is very strong but not used in casting. A356 is one of the strongest castable aluminum alloys.
Cast Aluminum vs. Other Metals
| Material | Approx. Tensile Strength (MPa) | Notes |
|---|---|---|
| Cast Aluminum | 140–320 | Lightweight, corrosion resistant |
| Cast Iron | 150–400 | Heavier, brittle, excellent wear |
| Mild Steel | ~400 | Stronger but heavier and rust-prone |
| Magnesium Alloy | 150–250 | Lighter, but less corrosion-resistant |
Why Strength Isn’t the Only Factor
While strength is important, your material choice should also consider:
- Weight (density of aluminum is ~2.7 g/cm³)
- Corrosion resistance
- Machinability and weldability
- Thermal performance
- Cost and availability
Applications Where Cast Aluminum Strength Matters
- Automotive: Intercooler tanks, suspension arms, wheels
- Aerospace: Brackets, housings, engine components
- Industrial Equipment: Pump housings, enclosures, structural frames
Tips for Maximizing Cast Aluminum Strength
- Choose the right alloy – A356-T6 is often the best balance of strength and castability.
- Avoid sharp corners and thin walls – Reduce stress concentrations.
- Use proper heat treatment – T6 heat treatment can increase strength by 50% or more.
- Work with an experienced foundry – Proper gating and solidification control are essential.
Conclusion
Cast aluminum can offer excellent strength-to-weight ratio, making it a top choice for demanding structural components. By selecting the right alloy and process, you can achieve performance that rivals heavier metals—while saving weight, cost, and corrosion concerns.
💬 Looking for strong, reliable cast aluminum parts for your project?
We specialize in gravity casting and low-pressure die casting of high-strength aluminum alloys. Contact us today to discuss your project and get a free consultation.
📧 Joanna@endtanks.com
