Pure aluminum melts at 660.32°C (1220.58°F), often rounded to 660°C in the shop. That number only applies to pure aluminum. Add alloying elements and aluminum no longer has a single melting point—it melts over a range. When you buy material or plan a casting run, the number that matters is the range for your grade, not the 660°C round figure. Get the range right and you set melt temperature, fill behavior, and part quality correctly.
A que temperatura derrete o alumínio?
Pure aluminum melts at 660.32°C, which is 1220.58°F. In daily communication, most shops say 660°C or 1220°F. The value comes from the crystal structure of pure aluminum: at this temperature the atoms gain enough energy to break the metallic bonds, and the solid turns liquid.
Two practical points follow. First, 660.32°C is a benchmark, not a process setting—unless you are melting near-pure metal (the 1xxx series), your melt temperature is set by the alloy’s range. Second, purity shows up in melting behavior: high-purity aluminum melts over a window of only 1–2°C, and when the range stretches past about 5°C, the material almost certainly contains noticeable impurities. That makes the melting window a useful incoming-inspection signal. Recycled aluminum is a good example—mixed scrap widens the range, which is why it has to be sorted by grade before remelting.
Why Do Aluminum Alloys Melt Over a Range?
Aluminum alloys do not have one melting point. They have a solidus and a liquidus. The solidus is where melting starts; the liquidus is where melting is complete. The band between them is the mushy zone, and it matters in casting: metal in this band flows but does not feed well, so thick-to-thin transitions can develop shrinkage porosity if the casting is not handled right.
Solidus and Liquidus
Below the solidus the alloy is fully solid; above the liquidus it is fully liquid. The wider the range, the more carefully you have to control cooling and feeding during casting, otherwise solidification shrinkage goes uncompensated and the casting comes out with internal porosity.
Why Al-Si Alloys Dominate Casting
The eutectic temperature of aluminum-silicon alloys drops to about 577°C, among the lowest of the common aluminum systems. Lower melting means lower melt energy, longer tool life, and better die filling, which is why both gravity and low-pressure casting favor Al-Si grades.
Alloying changes the melting point in three main ways:
- Eutectic formation pulls the melting temperature down to the eutectic point of the composition, as with Al-Si at about 577°C
- Solid-solution formation turns melting into a range instead of a point
- Precipitate phases shift the solidus position, which is why heat-treatable grades like 6061 and 7075 behave differently from casting alloys
| Sistema | Characteristic temperature | Nota |
|---|---|---|
| Al-Si eutectic | ~577°C | Casting workhorse, low melt, good flow |
| Pure aluminum | 660.32°C | Single point, window of only 1–2°C |
| Common Al-Si casting alloys | 538–613°C | Grade dependent, see next section |
Factors That Affect Aluminum’s Melting Point
Alloy composition is the main factor: different grades melt over different ranges. Purity, impurities, and measurement method also affect the reading, but far less than the alloying elements.
Alloy Composition
Si, Cu, Mg, and Zn all lower or shift the melting temperature. Composition sets the position of the solidus and liquidus, so once the grade is fixed, the range is largely fixed too. This is why two similar-looking alloys, such as 6061 and 6063, still call for different melt and pour temperatures in the foundry.
Purity and Impurities
Purer metal has a narrower melting range, and impurities widen it—a pattern you can use as an incoming-inspection signal, especially when recycled aluminum is mixed.
Two smaller factors are still worth knowing when you read a value:
- Measurement method: DSC, dilatometry, and visual methods all depend on heating rate and sample size, so the method should be noted with the reading
- Pressure and grain structure: pressure changes melting behavior, and grain structure affects how uniformly the phase change happens
Melting Ranges of Common Aluminum Alloys
Grades differ by a lot, so check the range before you choose. Below are typical melting ranges for common casting and wrought aluminum alloys; use the supplier’s data sheet as the final word.
| Grau | Melting range (°C) | Typical use |
|---|---|---|
| A356 | 557–613 | Gravity and low-pressure structural castings |
| 356 | 550–620 | General-purpose castings |
| A380 | 538–593 | Die-cast housings |
| 383 | 538–593 | Die castings |
| 319 | 482–638 | Automotive parts, pump bodies |
| 6061 | 582–652 | Extrusions, machined parts |
| 2024 | 502–638 | Aerospace structures |
| 5052 | 607–650 | Sheet metal, tanks |
| 7075 | 477–635 | High-strength structures |
Two patterns stand out. Casting alloys such as A356 and A380 sit lower and narrower, which suits thin sections and complex molds. Wrought alloys like 6061 and 7075 sit wider and need more care in the foundry. Even the same grade can vary slightly between batches, so the supplier’s data sheet is what you should use to set melt and pouring temperatures.
Aluminum vs Steel, Copper, and Titanium
Aluminum sits on the low end among common metals, with a melting point roughly half that of steel. That is both an advantage and a limit.
| Metal | Melting point (°C) |
|---|---|
| Aluminum (pure and alloys) | 477–660 |
| Ferro fundido | 1127–1204 |
| Aço carbono | 1371–1593 |
| Titânio | 1668 |
A lower melting point means shorter time to temperature, lower energy bills per melt, and longer tooling life, because the mold sees less thermal stress per cycle. The same property caps service temperature—parts that run hot for long periods lose strength well before the metal melts, which is why aluminum is kept away from sustained high-temperature duty.
How Melting Point Shapes Aluminum Applications
The low melting point pays off across casting, extrusion, and welding: lower melt energy, longer tool life, better die filling, and controlled cost when recycling scrap. In gravity and low-pressure casting, the low pouring temperature means shorter cycle times and less thermal shock on permanent molds. In welding, heat input has to be managed tightly and filler selection follows the base alloy’s range.
A few operating limits are worth remembering:
- Aluminum exposed to about 150–200°C for long periods loses strength noticeably; check structural parts against their working temperature
- Melt temperatures that run too high speed up oxidation and gas pickup; control superheat by grade
- Scrap must be sorted—mixed material widens the melting range and throws composition off
Perguntas mais frequentes
What is the melting point of aluminum?
Pure aluminum melts at 660.32°C (1220.58°F); alloys melt over a range between solidus and liquidus.
Why doesn’t aluminum have a single melting point?
Alloying elements make melting happen between the solidus and liquidus, and the composition sets where that range sits.
Which aluminum alloy melts the lowest?
Of the common grades, 7075 has the lowest solidus (about 477°C); among casting alloys, A380 and 383 sit low overall at 538–593°C.
How does aluminum compare with steel?
Aluminum melts at about 660°C, carbon steel at 1371–1593°C—roughly double, which is why aluminum is not for high-temperature service.
Conclusão
Keep three numbers in mind: 660.32°C for pure aluminum, about 577°C for the Al-Si eutectic low point, and 477–660°C across common aluminum alloys. Decide the application first, check the grade range second, and set the process parameters from the range. The range, not the round number, is what you plan around.
If you have drawings or working conditions to evaluate for an aluminum grade, send us the service temperature and loading—we will recommend a grade for your actual case. Need fundição por gravidade ou fundição a baixa pressão help, or want to talk through aluminum alloy selection? We will take it from there.
