Melting Point of Aluminum: Here is the ANSWER!

Aluminum is a silvery-white metal used extensively in various industries. It is an essential material in modern manufacturing processes, such as casting and injection molding. Manufacturers melt this material, shape it, and make unique products. However, when it comes to the melting point of aluminum, many seem to be confused.

 

The aluminum melts at a temperature of 660.3°C (1220.5°F). At this temperature range, the bond between atoms of aluminum breaks. Those atoms start to move freely. So, aluminum fails to maintain its solid structure and changes into a liquid state. However, the melting of impure aluminum can vary from pure one.

 

The melting point seems to be a stand-alone term. However, when aluminum melts, many changes happen. In this article, I will explain everything related to the melting point of aluminum and explain why knowing it is crucial. So, let’s get started!

 

Why Is Knowing the Melting Point of Aluminum Important?

 

Before discussing the importance of melting point, let’s first look at this melting point!

 

The melting point is the temperature range at which a metal changes its state. By absorbing heat, it goes from a solid state to a liquid state. This shift from solid to liquid happens at a specific temperature called the melting point. Each metal or material has its unique melting point.

 

Knowing the aluminum melting point is very important. Why? Here are some key logics:

• During welding, the melting point helps in creating the right welds. We might overheat the material if we don’t know aluminum’s melting point. This will result in a wrong weld of very low quality. It might also create a bigger HAZ (Heat Affected Zone).
• First, aluminum is used in injection molding processes. In this process, this metal is melted and then put into a mold to create a product of a specific shape. Knowing the melting point of aluminum helps to know which temperature is best for its melting. If we don’t know, we may increase the temperature, affecting aluminum quality.
• Aluminum is used in different projects. If we don’t know its melting point, we will end up using it at the wrong temperature. Imagine you make an aluminum product that is used at a temperature over 700 degrees Celsius. This will result in the product getting melted. We can make the product under 600 degrees Celsius when we know the melting point.

 

What is the Melting Point of Aluminum?

 

The aluminum melts at a temperature of 660.3°C (1220.5°F). 

 

If temperatures are anything below this range, aluminum will remain in a solid state. It won’t undergo a shift in its state (solid to liquid). Let’s discuss the changes that happen when the aluminum melts. As you know, aluminum atoms are tightly held together in crystalline structures. When aluminum undergoes heating, the aluminum absorbs the kinetic energy.

 

However, this energy is insufficient to break the bond between aluminum atoms. When we increase the temperature, the aluminum’s atoms start to vibrate. However, this vibration is not violent. So, the bond between atoms does not break, and the crystalline structure of aluminum remains stable. 

 

However, as the temperature increases, the vibration of atoms becomes more violent. When the temperature reaches 660.3°C (1220.5°F), the aluminum atoms become aggressive. The bond between atoms is broken. These atoms move freely and destroy the stable solid structure. As a result, the aluminum melt shifts from a solid into a liquid state.  

 

Here is a table showing the melting point of aluminum at different scales: 

 

Temperature Scale	Melting Point of Aluminum
Celsius (°C)	660.3°C
Fahrenheit (°F)	1220.5°F
Kelvin (K)	933.5 K

 

Remember, the table above shows the melting range for pure aluminum. However, if the aluminum is impure, its melting point can vary from the table. Moreover, aluminum and other alloy elements will melt at different temperatures. Therefore, it is key to note the melting point of aluminum before using it for any application.

 

Melting Point of Aluminum Alloys

 

Aluminum alloys don’t have fixed melting points. Instead, they have a range between 463°C (865°F) and 700°C (1292°F). The melting point of alloys depends on the melting point of the alloy element. An alloy with a low melting point will reduce the overall alloy melting point and vice versa.

 

Let me explain the melting point of aluminum alloys with two simple examples. The melting point of aluminum beryllium alloy is higher than that of pure aluminum. Why? Because beryllium has a higher melting point of around 1287 degrees Celsius. So, when beryllium is present as an alloy element with aluminum, it increases the melting point. 

 

To melt the beryllium present in aluminum, you’ll have to provide more heat. Therefore, aluminum beryllium alloys melt around 700°C  instead of 660°C. On the other hand, the melting point of aluminum zinc alloy is lower than that of pure aluminum. The reason is that zinc has a melting point of 419.5°C. 

 

When this metal is present in alloy with aluminum, it melts quickly. So you won’t have to provide more heat. This results in lowering the melting point of the alloy. The aluminum zinc alloy melts at around 475 degrees Celsius. So, if the alloy element has a higher melting point, it would increase the melting point of the alloy combination.

 

Quick Highlight: The modern melting temperature of aluminum and alloy is beneficial. How? CNC machining of aluminum becomes smoother and less challenging. When tools cut the aluminum, it does not overheat due to its moderate melting range. Therefore, manufacturers consider aluminum suitable for CNC-based machine manufacturing.

 

Melting Point Comparison of Aluminum with Other Metals

 

The aluminum melting point is not very high. This makes it less suitable to use heat-resistant products. However, aluminum ranks somewhere in the midrange when it comes to comparison. There are many metals whose melting point is higher than aluminum. They are more suitable for heat-resistant parts and products. 

 

On the flip side, some metals are less resistant to heat. Their melting point is even lower than that of aluminum. Here is a table showing a comparison of aluminum with other metals:

 

Metal / Alloy	Melting Point (°C)	Metal / Alloy	Melting Point (°C)
Aluminum	660.3	Iron	1538
Zinc	419.5	Titanium	1668
Tin	231.9	Nickel	1455
Lead	327.5	Magnesium	650
Brass	~900–940	Bismuth	271.4
Bronze	~950–1050	Mercury	-38.83
Copper	1085	Gold	1064

 

Brass melts at around 900 degrees Celsius, depending on its composition. Similarly, the melting point of copper is around 1085 degrees. Both of these two materials are more heat resistant than the aluminum. So, manufacturers prefer using them when they make products that are used in high heat. 

 

However, aluminum is superior to many other metals with low melting points. What makes it stand out is its lightweight and corrosion resistance. Parts made with aluminum generally remain in good shape for many years. Moreover, aluminum is inexpensive, making it popular for many projects.

 

Factors that Affect the Melting Point of Aluminum

 

The aluminum melting point is not an independent property. Many factors highly influence it. Under different conditions, the melting point of aluminum changes from its pure form. Here is the list of factors that affect its melting point:

 

1- Alloying Elements

Alloy elements impact aluminum’s melting point. Elements with higher melting points increase aluminum’s melting point, and vice versa. In the above section, I mentioned examples of aluminum beryllium and aluminum-zinc alloys. Beryllium has a higher melting point, which increases the melting point of aluminum beryllium alloy. Similarly, aluminum-zinc alloy has a lower melting point due to zinc’s low melting point.

 

2- Purity of Aluminum

During production, some impurities can be mixed with the aluminum. Thus, it does not remain pure, and its melting point can vary from 660 degrees Celsius. The size and quantity of the impurity define its effect on the aluminum melting point. Moreover, if the melting point of the impurity is high, it would increase the melting point of aluminum and vice versa.

 

3- Pressure Condition

This is the most crucial factor that influences the melting of aluminum. If you keep the aluminum at a high temperature, it will take more heat to melt. Why? Because at higher pressure, the atoms of aluminum get very close together. So, breaking their bond becomes more challenging and requires more heat. So, you’ll have to provide a high temperature to break bonds and melt aluminum.

 

4- Grain structure

As you know, the structure of aluminum consists of multiple grains or crystals. The size of these grains plays a key role in defining the melting point. If aluminum has a smaller grain size, it will have a lower melting point. Why? Because breaking small grains is relatively straightforward. If the grain size is bigger, it provides extra stability to the aluminum. So, aluminum with a bigger grain will require more heat for melting. 

 

Frequently Asked Questions

 

At what temperature does aluminum melt?

Aluminum melts at 660.3°C (1220.5°F) for pure aluminum. If it has some impurity, its melting point will differ depending on the type of impurity.

 

Does aluminum melt or burn?

Aluminum melts when the temperature reaches around 660.3 degrees Celsius. Remember, even most of its alloys do not burn under normal conditions.

 

Why is aluminum difficult to melt?

Aluminum is not very difficult to melt. Its melting point is 660 degrees Celsius. Achieving this temperature is easier and can be done anywhere. However, some expertise and skill are required to get the job done.

 

Is aluminum melting reversible?

Yes, aluminum is one of those metals that can be melted and then solidified again. For example, you melt aluminum, and it becomes liquid. After you decrease the temperature to a very low level, the aluminum will be solid again. Its atoms will create bonds with each other.

 

Conclusion

 

Knowing aluminum’s melting point is crucial. It helps in selecting this metal for any application. If you don’t see the melting point of aluminum, you’ll end up using it for the wrong applications. Imagine making production with that for use in high-temperature conditions. 

 

It would result in damaging the part, wasting your time and energy. In this article, I have discussed the melting point of pure aluminum and its alloys. Moreover, you’ll also see the comparison of aluminum with other metals’ melting points. This will help you understand which metal is suitable for you.