Key Differences of 6061 vs 6063 Aluminum Alloys

The 6000 aluminum series are some of the most popular aluminum alloys primarily alloyed with magnesium and silicon. As a class, they are sometimes thought of as ‘architectural’ or ‘structural’ aluminum. Two alloys in this class stand out due to how common they are: 6061 and 6063 aluminum.

These metals are found in just about every use of cut-to-size aluminum plate and bar stock, making everything from bicycle frames to decorative windows. They combine their lightweight with medium-to-high strength and excellent workability, making them very versatile.

In spite of being in the same class and sharing many of the same properties, many still wonder about the differences in 6061 vs 6063 aluminum.

They are differentiated in their use cases—some are merely aesthetic, while others are more integral to their strength. The alloying elements in each alloy contribute to these differences, impacting their applications as structural aluminum.

Mechanical Properties of 6061 vs 6063 Aluminum Alloys

Comparing 6061 and 6063 aluminum isn’t straightforward because each alloy is used in different tempers. These alloys are available in naturally aged T4 and artificially aged T6 tempers. The artificially aged versions, which undergo a heat treatment process, are much stronger than their T4 equivalents.

A complete comparison of the mechanical properties of 6061 vs 6063 aluminum can be viewed in the table below:

Mechanical Properties	6061 Aluminum		6063 Aluminum
Property	T4 6061	T6 6061	T4 6063	T6 6063
Brinell Hardness	65	95	46	73
Tensile Strength	35,000 psi	45,000 psi	25,000 psi	35,000
Yield Strength	21,000 psi	40,000	13,000 psi	31,000
Modulus of Elasticity	10,000 ksi	10,000 ksi	10,000 ksi	10,000 ksi
Shear Modulus	3,770 ksi	3,770 ksi	3,740 ksi	3,740 ksi
Shear Strength	24,000 psi	30,000 psi	16,000 psi	22,000
Anodization Reaction	Good	Good	Good	Good
Composition	6061		6063
Aluminum	95.8 – 98.6%		<=97.5%
Chromium	.04-.35%		<=.10%
Copper	.15-.4%		<=.10%
Iron	<=.7%		<=.35%
Magnesium	.8-1.2%		.45-.90%
Manganese	<=.15%		<=.10%
Silicon	.4-.8%		<=.2-.6%
Titanium	<=.15%		<=.10%
Zinc	<=.25%		<=.10%

As the table demonstrates, 6061 aluminum alloy, in its most common tempers, is significantly stronger than its near equivalent, 6063 aluminum. Untempered naturally aged 6061 is roughly on par with heat-treated 6063 aluminum and actually exceeds 6063 T6 aluminum’s shear strength.

With the strength of 6061’s aluminum significantly outclassing 6063, some may wonder why anyone would choose anything but 6061 aluminum over 6063. The answer lies in the two aluminum alloys’ composition.

Aluminum alloy 6063 is purer and contains fewer additional metals. While this reduces its strength and makes it less workable than 6061, it does enhance the aluminum’s appearance, making it more amenable to aesthetic coating processes, such as anodizing.

This is why 6063 aluminum is often used in architectural aluminum applications, such as door frames and aluminum extrusion projects.

Additionally, 6063 aluminum is prized for its excellent corrosion resistance, making it a preferred aluminum grade for decorative and architectural uses where both appearance and better corrosion resistance are critical.

Applications of 6061 vs 6063 Aluminum

When it comes to aluminum alloys, 6061 and 6063 stand out for their unique properties and strengths. These versatile materials are essential in various applications, from heavy-duty structural components to intricate architectural designs.

Understanding the differences between 6061 and 6063 can help you choose the right alloy for your next project.

6061 Aluminum Alloy

6061 aluminum is widely recognized for its high strength and versatility. It is commonly used in structural applications where durability and strength are paramount. This includes automotive and aerospace parts, where the material’s ability to withstand stress and impact is crucial.

Additionally, 6061 aluminum is used in machinery and equipment manufacturing, making parts such as frames, hydraulic pistons, and heat sinks. Its excellent machinability makes it a favorite in welding and fabrication projects, including welded assemblies and heavy-duty construction components.

6063 Aluminum Alloy

On the other hand, 6063 aluminum is often referred to as architectural aluminum due to its superior surface finish and excellent corrosion resistance. It is ideal for applications where appearance and aesthetic appeal are important, including door frames, window frames, and other architectural materials.

The alloy’s good corrosion resistance and ability to be easily extruded into complex shapes make it a preferred choice for aluminum extrusion products, such as pipes, tubing, and other profiles. Additionally, 6063 resists corrosion and is used to manufacture furniture, lighting fixtures, and sports equipment, where both form and function are essential.

While 6061 vs 6063 aluminum offers a comparison of strength and structural capabilities versus superior corrosion resistance, both alloys share the same magnesium and silicon alloying elements.

6063 aluminum, with its higher thermal conductivity and corrosion-resistant properties, excels in applications requiring a high-quality finish and durability against environmental factors.

Custom Solutions with Exceptional Service From Industrial Metal Services

Any fabricators or machinists who commonly work with aluminum will need a supply of 6061 around for general projects or shop use. In contrast, 6063 is most widely used in prefab architectural trim, where strength is often secondary to appearance.

It is commonly said that 6061 aluminum is a structural metal, while 6063 is an architectural metal. Although 6063 aluminum alloy possesses significant strength, it excels in various applications, such as making impact-resistant window frames that withstand hurricanes. However, it isn’t suitable for building bridges or other structures that require the strength of 6061 aluminum alloy.

Industrial Metal Service specializes in providing process-ready, cut-to-order 6061 aluminum to machine shops and fabricators nationwide. With our speed of delivery, top-notch customer service, and out-of-the-box thinking, we ensure you receive the best solutions for your aluminum needs.

Contact us to secure 6061 and 6063 aluminum alloys cut-to-size for complex shapes at a fair price anywhere in the continental United States.