Flexible, Durable, Reciclable…
Just Aluminum!

It’s impossible for aluminum to be 100% pure, but aluminum in this wrought series category contains at least 99% aluminum. For all intents and purposes, 1xxx alloys are considered pure aluminum. Notably, this alloy is the exception to the wrought series naming rule — in 1xxx alloy names, the last two digits stand for the minimum percentage of aluminum above 99. For example, Alloy 1350 consists of at least 99.50% aluminum.

Pure aluminum has great corrosion resistance and workability, plus high electrical and thermal conductivity. For this reason, this alloy is often used for electrical and chemical applications. Pure aluminum is not very strong and is seldom used for structural applications, but strain hardening can moderately increase material strength.

This wrought series alloy offers high strength and performance over a wide range of temperatures and is regularly used in aerospace applications. One well-known aircraft aluminum alloy is Alloy 2024. However, some copper aluminum alloys are susceptible to heat and stress corrosion cracking and are considered non-weldable, whereas other 2xxx alloys can be welded using the right methods. 2xxx decreases the elongation and tensile strength of aluminum and doesn’t offer as good corrosion resistance as other alloys in the wrought series.

3xxx aluminum alloys were first used only in pots and pans, but are now widely used in heat exchanger components for vehicles and power plants. With good temperature stability and corrosion resistance, alloys in this category are suitable for use in extreme conditions. 3xxx also allows for good formability and workability. 3003 is a popular manganese alloy used for moderate strength applications that require complex shapes.

Silicon reduces aluminum’s melting point and improves its fluidity when molten. For this reason, 4xxx alloys are often used in fusion welding wire and as brazing alloys. Silicon on its own is non-heat-treatable, but a number of 4xxx alloys respond well to heat treatments thanks to added copper or magnesium.

Aluminum alloys in this category are easily weldable and widely used for applications in shipbuilding, transportation, bridge building, and construction. 5xxx alloys offer good corrosion resistance in marine environments and have the highest strength of all non-heat-treatable alloys. However, 5xxx alloys with more than 3 to 3.5% magnesium are not recommended for elevated temperature service above 65.6°C (150°F) due to the possibility of stress corrosion cracking.

6xxx alloys usually consist of around 1.0% magnesium and silicon each, which produces magnesium-silicide. Magnesium-silicide can support solution heat treatments that improve strength, formability, and corrosion resistance. This wrought series number is used throughout the welding fabrication industry, primarily incorporated into structural components and extrusions.

These alloys are sensitive to solidification cracks, which means they should not be welded without filler materials — oftentimes, 6xxx is welded with 4xxx or 5xxx filler materials to increase weldability. A major magnesium-silicide alloy is 6061, which is one of the most versatile heat treatable aluminum alloys.

This wrought series number contains some of the highest strength aluminum alloys that are best-suited for high-performance applications in competitive sporting equipment or the aircraft and aerospace industries. Zinc additions range from 0.8 to 12% in 7xxx alloys and can be coupled with smaller percentages of magnesium, copper, and chromium for heat treatability.

Like 2xxx, 7xxx contains alloys both suitable and non-suitable for welding — one commonly welded alloy is 7005, which is primarily used with 5xxx alloy fillers. One of the highest-strength aluminum alloys available is 7075, which is often used in air-frame structures and for other high-stress applications.

It’s important to note which aluminum alloys are heat treatable and which are non-heat-treatable. This will help product teams determine appropriate applications for specific aluminum alloys, and protect components from high temperatures when necessary.

• 2xxx, 6xxx, and 7xxx series alloys are heat treatable.
• 1xxx, 3xxx, and 5xxx series wrought aluminum alloys are non-heat-treatable and only allow for strain hardening.
• 4xxx series contains some heat-treatable alloys, but mostly non-heat-treatable alloys. However, most 4xxx non-heat-treatable alloys can respond to heat treatments when mixed with other heat-treatable alloys.