Heat Treatable Aluminum Alloy Series

We wouldn’t be able to enjoy our world without aluminum. From cans holding vegetables to cars and aerospace technologies, aluminum alloys are a significant part of our world. When we think of aluminum, the reflective and light material comes to mind.

Yet aluminum is very strong, durable and malleable, especially when combined with other elements. When we take the base element of aluminum and combine it with other elements such as magnesium, zinc or copper, it is then considered to be an aluminum alloy.

The reason why we combine aluminum with these other elements is often to strengthen the metal based on its application. There are typically two ways that can be used to strengthen the metal. One process is through heat treatment and the other is through cold working.

Heat Treatable Alloys

Heat treatable aluminum alloys consist of pure aluminum that is heated up to a certain point. Then the alloy elements are homogeneously added as the aluminum takes on a solid form. The heated aluminum is then quenched as the rapidly cooling atoms of the alloy elements are frozen in place.

The precipitate is formed when the aluminum atoms and alloy element atoms combine during a natural aging process done at room temperature or through artificial aging in a furnace set at a low temperature.

The Aluminum Association administers a designation for aluminum alloys that have been combined with an alloy element as they are classified into specific groupings. These designations consist of a 4-digit number. The first digit in the number identifies the alloy element that was added.

The second digit will tell you if there were any modifications to the base alloy during the heat treatment process. The last two digits in the designation provide information about the minimum aluminum content that is present.

Each designation is grouped into a specific series based on their composition, characteristics and added alloy element. Heat treatable alloys usually fall into 3 designation groupings: 2xxx series, 6xxx series and 7xxx series.

Heat Treatable 2xxx Aluminum Alloys

Aluminum in this series have up to 15% copper as the alloying element. This type of aluminum alloy has an incredible toughness and high strength. The drawback is that this alloy has low resistance to atmospheric corrosion. So the metal may be painted or clad with another high-purity alloy. Aluminum alloys in this series are commonly used for small aircrafts, appliances, fasteners and other applications.

Heat Treatable 6xxx Aluminum Alloys

Silicon and magnesium are combined with aluminum and heat treated to make a weldable metal that is versatile and possesses moderately high strength. This aluminum alloy has greater corrosion resistance, and will often be used to clad 2xxx series aluminum alloys.

Due to having good weldability properties, aluminum alloys in the 6xxx series are commonly used in manufacturing automobile parts, truck components, pipelines, and marine frames as well as structural applications.

Heat Treatable 7xxx Aluminum Alloys

For aluminum alloys in the 7xxx series, zinc is commonly the alloying agent although small quantities of copper, magnesium and chromium may also be added to make it heat treatable. These alloys, when combined with aluminum, make an extremely strong material used primarily in commercial aircraft structures. It is also found in mobile equipment, recreational equipment and ordinances.

Based on the type of application, heat treatable aluminum alloys can be used during your manufacturing processes to create a range of products and structures. Here at Belmont Metals, our metallurgical experts can provide you with additional technical information regarding heat treatable aluminum alloys and their possible applications. We can also provide advice about special alloys and custom alloys that may fit into your manufacturing needs and varied specifications.