Ask ten people for the melting point of aluminum and you’ll probably get the same answer: 660 degrees Celsius. Technically correct, but only if you’re talking about pure aluminum in a lab. The aluminum you actually work with on the shop floor (the bars, the profiles, the tubing, the sheet) almost never behaves at exactly 660°C, because it’s almost never pure aluminum. It’s an alloy, and every alloy has its own melting behavior that matters far more for real fabrication, welding, and machining decisions than the textbook number.

If you weld aluminum, machine it, anneal it, or spec it for high-temperature applications, this article gives you the practical picture: what the melting point actually is, why it varies, and how it shows up in everyday fabrication work.

The Melting Point of Pure Aluminum

Pure aluminum melts at 660.32°C (1220.58°F). This is the temperature at which the solid metal becomes liquid under standard atmospheric pressure. It’s a relatively low melting point compared to other common structural metals, which is part of why aluminum is so widely used: it can be cast, extruded, and recycled at temperatures far below those needed for steel.

A few related thermal properties worth keeping in mind:

• Boiling point: 2,470°C (4,478°F)
• Density at room temperature: 2.70 g/cm³
• Density when liquid: about 2.375 g/cm³
• Specific heat capacity: 0.897 J/g·K
• Thermal conductivity: 237 W/m·K (one of the highest among metals)
• Latent heat of fusion: 397 J/g

The high thermal conductivity is the reason aluminum is the go-to material for heat sinks. The relatively low melting point combined with the high specific heat is why aluminum extrusion is energy-efficient compared to steel.

Why Aluminum Alloys Melt at Different Temperatures

Here’s where things get interesting. Pure aluminum is too soft for most structural and fabrication work, so almost all the aluminum you encounter in industry is alloyed with elements like magnesium, silicon, copper, zinc, manganese, and chromium. These alloying elements change the melting behavior in ways that matter.

Alloys don’t have a single melting point. They have a melting range defined by two temperatures:

• Solidus temperature: The point at which melting begins
• Liquidus temperature: The point at which the alloy is fully liquid

Between these two temperatures, the alloy is partly solid and partly liquid (a slushy “mushy zone” that’s important for welding, casting, and heat treatment).

Here’s how the major aluminum alloy families compare:

Notice that 6063 melts in a narrower range, closer to pure aluminum, while alloys like 2024 and 7075 (used in aerospace) start melting at significantly lower temperatures because of their copper or zinc content. This is part of why these high-strength alloys are tricky to weld and require specialized techniques.

For most of the structural and architectural aluminum extrusions we produce at Exalum, you’re working with 6063 and 6061, both of which melt in the 580-655°C range. That’s a practical range that’s easy to control during extrusion, but you should never expose finished profiles anywhere close to it in service.

What This Means for Welding Aluminum

Welding aluminum is where the melting point story gets practical. Three rules every fabricator learns the hard way:

Aluminum doesn’t change color before it melts. Steel glows red, orange, then white as it heats. Aluminum stays silver-gray right up until it suddenly slumps and pools. There’s no visual warning that you’re approaching the melting point, which is why aluminum welding takes more skill than steel welding.

The heat-affected zone (HAZ) loses strength. Even areas that don’t melt during welding lose strength because the heat ages or anneals the alloy. For 6061-T6, the HAZ can lose 40 percent of its yield strength. Designers need to account for this with thicker sections at weld joints or post-weld heat treatment.

Filler metal selection depends on the alloy and the melting range. 4043 filler (with silicon) is common for 6xxx series alloys because it lowers the melting range and reduces cracking. 5356 filler (with magnesium) is the choice for stronger joints on 5xxx and 6xxx alloys. Match the filler to the alloy and the application.

Why Melting Point Matters for Extrusion

Aluminum extrusion (the process that produces the bars, profiles, channels, and tubes Exalum manufactures) doesn’t actually melt the aluminum. Billets are preheated to around 450-500°C, which is well below the melting point but soft enough to be forced through a steel die under enormous pressure.

This temperature window is critical. Heat the billet too little and the die won’t fill properly, producing surface defects and undersized profiles. Heat it too much, especially close to the solidus temperature, and the billet starts to develop hot tears, surface cracking, and internal porosity.

The control of this temperature window is one of the reasons consistent extrusion quality is harder than it looks. At our 20,000 m² vertically integrated facility, we maintain billet temperature within tight tolerances throughout extrusion runs to deliver the surface finish and dimensional consistency that fabricators expect.

When Operating Temperature Becomes a Design Constraint

Most aluminum fabrication never gets close to melting temperature in service, but designers still need to respect aluminum’s thermal behavior:

• Strength drops significantly above 200°C. A 6061-T6 part loses about half its yield strength at 200°C and most of it by 300°C.
• Continuous service above 100°C can cause gradual softening (overaging) in heat-treated alloys.
• Thermal expansion is roughly twice that of steel, which matters in long spans, mixed-material assemblies, and tight-tolerance work.
• Fire performance is generally non-combustible, but structural integrity is lost well below the melting point. This is why fire-rated aluminum cladding now uses specific tested systems rather than generic profiles.

For applications running near these limits (heat exchangers, motor housings, lighting fixtures, automotive parts), the alloy choice and the profile design matter more than headline strength numbers.

How Aluminum’s Melting Point Connects to Exalum’s Products

Almost everything we manufacture at Exalum involves working with aluminum near, but never at, its melting point. The extrusion press, the anodizing baths, the powder coat cure ovens all operate in temperature windows that are dictated by aluminum’s thermal behavior.

The product range that comes out of this controlled process covers most of what serious fabricators source:

• Square Hollow and Rectangular Hollow for structural framing
• Tubing Pipes and Decorative Tubing Pipes for railing, furniture, and architectural work
• Equal Angle and Unequal Angle for cross-bracing and brackets
• Unequal Channel for edge reinforcement and channel mounting
• Flat Bars and Round Bars for precision plates, spacers, and shaft stock
• Heat Sinks that exploit aluminum’s high thermal conductivity for electronic and motor cooling
• Curtain Wall, Casement Windows, Doors, and Sliding Doors for architectural projects
• Louvers, Partition, and Diffusers for ventilated and modular installations
• Handle, Door Jamb, and Showcase for finishing and retail applications

Each of these is extruded from alloys with melting behavior we control carefully through every step of production, then finished with in-house anodizing or powder coating that protects the metal across decades of service.

Sourcing Aluminum Profiles With Confidence

The melting point of aluminum is a starting point for understanding the material, not the destination. What actually matters in fabrication is the alloy you choose, the temper it’s delivered in, and the manufacturer who controls the temperatures from billet to finished profile.

Exalum Metal has supplied aluminum extrusion to fabricators since 2009 from our vertically integrated facility in Indonesia. The advantage of vertical integration is straightforward: we control the temperatures, the alloy chemistry, and the finishing process under one roof, which means the material that leaves our facility behaves exactly the way the spec sheet says it should.

Whether you need standard profiles or custom cross-sections designed for your specific fabrication requirements, Exalum Metal has the capacity and expertise to deliver.

Ready to place an order or discuss your requirements? Get in touch with the Exalum Metal team directly:

Email: [email protected] WhatsApp: +62 811 9429 970 Website: www.exalummetal.com

Your next fabrication project deserves material you can count on. Make aluminum profiles from Exalum Metal your standard.