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Choosing Between Aluminum 6063 or 6061 for Extrusions

May 7, 2024

Aluminum 6063 and 6061 are two of the most common extrusion materials, due to their affordability and long list of advantages. Depending on the exact application, one aluminum grade may be better suited than the other. Learn more about each material’s key properties, common applications, and how to decide between them.

Key Characteristics

Aluminum 6061 and 6063 are members of the 6000 series of aluminum alloys, wherein the numeral “6” denotes higher levels of magnesium and silicon than other aluminum alloys. Both grades are heat-treatable to enhance their material properties.

Aluminum 6061

The composition of aluminum 6061 includes more copper, silicon, chromium, and iron than aluminum 6063. The exact composition of most aluminum 6061 alloys is:

  • 97.9% Aluminum
  • 1.0% Magnesium
  • 0.6% Silicon
  • 0.28% Copper
  • 0.2% Chromium
  • 0.02% Zinc and other elements

Aluminum 6061 features good weldability, but it requires using the proper filler material to prevent solidification cracks. It also has good mechanical properties and greater basic strength than aluminum 6063. Other benefits of aluminum 6061 include moderate corrosion resistance and a decent machinability rating of 50%.

Aluminum 6063

Aluminum 6063 contains more aluminum and less magnesium and silicon than aluminum 6061. Its overall composition is less complex, typically containing only:

  • 98.9% Aluminum
  • 0.7% Magnesium
  • 0.4% Silicon
  • Trace amounts of copper, iron, and chromium

Aluminum 6063 is a more popular choice for aluminum extrusions, largely due to its greater aesthetic appeal. Anodized aluminum 6063 is such a common architectural material that many simply refer to it as “architectural aluminum.”

Good corrosion resistance further makes aluminum 6063 suitable for outdoor use, and its high weldability and brazability make it easier to assemble. While easier to shape and form than aluminum 6061, aluminum 6063 is less machinable than 6061.

Applications

Aluminum 6061 is a superior choice for applications that need greater strength and durability, such as:

  • Aerospace parts
  • Structural braces
  • Machinery components
  • Electrical fittings
  • Durable consumer goods
  • Scuba tanks
  • Food contact applications, such as:
    • Aluminum cans
    • Food container foil
  • Transportation components for:
    • Truck beds
    • Trailers
    • Yachts
    • Motorcycles
    • Bicycle frames

Aluminum 6063, by contrast, supports many more architectural and decorative applications, for instance:

  • Roofs
  • Window and door frames
  • Furniture
  • Stairs
  • Shelving
  • High-end casework
  • Face nosing
  • Signage
  • Trim
  • Architectural channels

Other common applications for aluminum 6063 include round tubing and pipes, such as irrigation tubes, electrical conduits, and other rounded extrusions.

Deciding Between Aluminum 6061 and 6063

Both 6000-series aluminum alloys make good choices for extrusions, but the better choice depends on their exact form and application. The following should serve as a useful shorthand when comparing the two for extrusion projects:

  • Alloy Composition:
    • 6061: Higher amounts of iron, copper, silicon, and chromium, resulting in higher strength and versatility.
    • 6063: Lower amounts of copper, making aluminum 6063 more corrosion-resistant.
  • Mechanical Properties:
    • 6061: Higher overall strength and hardness, with a Brinell hardness value of 95. Greater utility for more significant structural demands.
    • 6063: Moderate strength and lower durability (Brinell hardness value 73). Easy to shape and form, and amenable to attractive finishing options like soft anodizing.
  • Corrosion Resistance:
    • 6061: Good, but slightly less corrosion-resistant than 6063.
    • 6063: Superior corrosion resistance; withstands harsh weather.
  • Workability and Weldability:
    • 6061: Workable and, with added precautions, weldable.
    • 6063: Easier to weld and form, making more complex shapes possible.
  • Applications:
    • 6061: More suitable for structural applications.
    • 6063: Preferred for architectural projects and those requiring more visual appeal.
  • Heat Treatment:
    • 6061 and 6063 can both be heat-treated to improve certain mechanical properties.
  • Extrusion:
    • 6061: An effective choice for more durable and less complex extrusion shapes.
    • 6063: Generally the first pick for extrusions, and usually necessary for more intricate designs.

Contact PSI Extrusions for All Your Aluminum Extrusion Needs

PSI Extrusions has extensive experience extruding aluminum 6061 and 6063 for a variety of fabrication projects. Our in-house quality control labs and ISO 9001:2015-certified quality management system ensure customers receive nothing but the finest extrusions, made to their exact design specifications. In addition to extrusion services, we also offer turnkey fabrication capabilities through CNC machining, powder coating, anodizing, assembly, special packaging, and more.

For further assistance comparing the advantages of aluminum 6063 and 6061, contact us today. To get started on your extrusion project, request a quote.

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