The melting point of pure aluminum is a precise physical constant: 660.3°C (1220.5°F).
Yet, in manufacturing, construction, and aerospace, we almost never use pure aluminum but aluminum alloys. By adding elements such as silicon, magnesium, and copper, we greatly increase aluminum’s strength, durability, and workability, but we also change one of its core properties—its melting point.
The Benchmark: Pure Aluminum
As mentioned at the beginning, the melting point of 100% pure aluminum is 660.3°C (1220.5°F). This is a certain temperature point at which pure aluminum changes from solid to liquid. This value is the reference benchmark for the properties of all aluminum alloys.
Why Aluminum Alloys Have a Melting Range
Unlike pure metals, alloys are made by mixing two or more metallic elements. This mixture causes the alloy to not have a single melting point, but a melting range.
This range has two key points:
Solidus: The temperature at which the alloy begins to melt. Below this temperature, the alloy is completely solid.
Liquidus: The temperature at which the alloy completely melts into a liquid. Above this temperature, the alloy is completely liquid.
Between these two temperatures, the alloy is in a “paste” state where solid and liquid coexist. Understanding this range is critical for processes such as casting and welding.
Cheat Sheet: Melting Points of Common Aluminum Alloys
For engineers, designers, and purchasers, specific alloy melting point data is the most useful. The following table lists some of the most common aluminum alloys and their melting point ranges.
| Aluminum Alloy | Melting Point Ranges (°C) | Melting Point Ranges (°F) | Main Features and Applications |
| 1100 | 643 – 657 °C | 1190 – 1215 °F | Commercially pure aluminum, excellent corrosion resistance and formability. Used in chemical equipment and reflectors. |
| 3003 | 643 – 654 °C | 1190 – 1210 °F | The most common general-purpose alloy, medium strength. Used for cookware, storage tanks, and pipes. |
| 5052 | 607 – 649 °C | 1125 – 1200 °F | One of the strongest non-heat-treatable alloys, with excellent resistance to seawater corrosion. Used in ships, fuel tanks. |
| 6061 | 582 – 652 °C | 1080 – 1205 °F | The most versatile heat-treatable alloy with high strength and good weldability. Used in building structures, bicycle racks. |
| 7075 | 477 – 635 °C | 890 – 1175 °F | One of the strongest aluminum alloys, comparable to steel. Used in aerospace components and high-strength molds. |
Note: The above values are typical ranges and may vary slightly due to slight differences in alloy composition.
A special case: the melting point of aluminum oxide
Aluminum has a very interesting property: it reacts immediately with oxygen in the air, forming a very thin but very dense protective layer on the surface – aluminum oxide (Al₂O₃).
This aluminum oxide has a melting point of 2072°C (3762°F). This explains why aluminum products are so corrosion-resistant. During hot processes such as welding, this high-melting oxide layer must be destroyed before the aluminum underneath can fuse.
Why is melting point important to manufacturing and engineering?
Understanding aluminum’s melting point is more than just an academic question; it directly affects manufacturing costs, product quality, and final performance.
Casting and die casting: Precisely controlling the temperature between the solidus and liquidus is critical to ensure complete mold filling and avoid casting defects.
Welding: Welding requires providing enough heat to melt the parent metal, but not too high a temperature to degrade the material or burn through.
Heat treatment: Heat treatment processes such as annealing, solution treatment, and aging are performed at carefully controlled temperatures that are below the alloy’s solidus but high enough to change its microstructure to improve strength.
High temperature applications: When designing products for use in high temperature environments, such as engine components or cookware, it is important to consider that aluminum alloys can begin to lose mechanical strength well below their melting point.
How to Choose the Right Aluminum Alloy for Your Project
Choosing the right aluminum alloy requires balancing performance, processability, and cost. The melting point is just one of many considerations.
At Huaxiao Metal, we not only provide high-quality aluminum but also provide professional knowledge support. If you have questions about the selection of aluminum alloys for a specific application or need more detailed performance data to meet the needs of your project, our team of experts is ready to help you.
