6061 vs 6063 Aluminum: Choosing Between Two Exceptional Metals

6061 vs 6063 Aluminum- Choosing Between Two Exceptional Metals

Aluminum remains one of the most common materials for manufacturing and construction purposes. Its excellent mechanical and physical properties make it ideal for numerous applications.

It is lightweight yet offers considerable strength, amongst other essential features.

Aluminum alloys

However, like other alloys, aluminum alloys have mechanical properties superior to pure aluminum. Aluminum is alloyed using elements like magnesium, copper, zinc, silicon, etc. Among the numerous aluminum forms, 6061 and 6063 alloys are some of the most popular.

This article distinguishes 6061 vs 6063 aluminum. Also, we will provide detailed information and guide you on which to choose for your manufacturing needs.

What is 6061 Aluminum?

What is 6061 Aluminum

Aluminum 6061 is one of the most prevalent aluminum alloys, often preferred for its superior strength, versatility and durability. It is precipitation-hardened, suggesting that it is strengthened through heat treatment.

The process involves heating and cooling metals to increase strength and change their mechanical properties, including the grain structure.

Besides aluminum, the alloy contains magnesium and silicon. Other elements added to improve its quality include copper, iron, and zinc.

These elements enhances the natural aluminum machinability, corrosion resistance, formability, fatigue resistance, weldability, etc.

Since the development of aluminum 6061 in 1935, it’s become one of the most used aluminum alloys in areas where a strong metal is required.

It suits construction, aerospace, food packaging, automotive, firearms, etc. The alloy exists in different tempered variants: 6061-T6 and 6061-T651, including the pre-tempered variant 6061-O.

Characteristics of 6061 Aluminum

As briefly introduced, aluminum 6061 possesses excellent mechanical properties.

Let’s examine some of its chief characteristics:

  • Strength: Like all aluminum variants, it has an excellent strength-to-weight ratio. This feature makes this alloy highly valuable for fabrication, which must be lightweight but not compensate for strength.
  • Machinability: This alloy possesses top-tier machining properties, perhaps the reason for its vast industrial applications.
  • Surface Property: The AL 6061 has a good appearance and surface properties, limiting the need for excessive expenses for finishing, especially for aesthetically appealing products.
  • Heat Treatment: It responds well to high temperatures. This makes heat treatment a suitable post-processing operation to harden and strengthen a particular fabrication.

Besides the above-listed properties, other characteristics of the aluminum 6061 include resistance to corrosion, a good conductor of electricity, etc.

Advantages of 6061 Aluminum

The advantages of aluminum 6061 are a function of the features and properties of this alloy.

Some of its benefits to the manufacturing industry include:

  • Excellent strength-to-weight ratio
  • Good corrosion resistance
  • Recyclability
  • Excellent machinability
  • Responds well to anodizing

Applications of 6061 Aluminum

Aerospace

Aluminum 6061 has a vast application in various manufacturing sectors of the world.

It is a valuable raw material to the following industries:

  • Aerospace
  • Building and Constriction
  • Electronics
  • Automotive
  • Consumer goods
  • Medical products and devices
  • Sports
  • Shipbuilding, etc.

The applications of this alloy often relate to its characteristics. For example, its lightweight and high tensile strength makes it suitable for manufacturing sporting equipment like golf clubs, bicycles, etc.

What is 6063 Aluminum?

What is 6063 Aluminum

As mentioned earlier, the aluminum 6063, like the AL 6061, belongs to the aluminum 6xxx series, so they share similar characteristics.

For example, they contain identical alloying metals – silicon and magnesium. Indeed, the alloy possesses enhanced mechanical properties compared to  natural aluminum; 6063 aluminum is not as common as 6061.

Aluminum 6063 is suitable for manufacturing processes that require high temperatures, making it the go-to candidate for aluminum extrusion. It also has good weldability, corrosion resistance and formability.

It is suitable for manufacturing complex shapes and structures with smooth, fine surfaces, especially after applying quality finishes such as anodizing.

The alloy is mainly adopted for exterior and interior architectural designs, including door and window frames, roofs, pipings, and tubings. The alloy is available in temper sub-variants, such as Aluminum 6063-O, 6063-T6, 6063-T5, etc.

Characteristics of 6063 Aluminum

The aluminum 6063 has good physical and mechanical properties, which accounts for its improved overall features.

Some include:

  • Machinability: This aluminum alloy is easy to cut, drill, form, reshape, mold etc. Generally, it’s an excellent choice for CNC machining and other manufacturing processes.
  • Conductivity: Like all aluminum forms, the 6063 is a good conductor of heat and electricity, making it suitable for creating electronics and electrical appliances.
  • Heat Treatment: AL 6063 responds incredibly to heat treatment. The alloy is often heat treated to improve its strength and overall durability.
  • Lightweight: Typical to aluminum, the 6063 aluminum alloy is a low density metal. This makes it a popular choice in light fabrications.

Other characteristics of this alloy include good surface appearance and response to post-processing operations, corrosion resistance, etc.

Advantages of 6063 Aluminum

All aluminum forms share similar benefits.

That said, the advantages of aluminum 6063 include the following:

  • Good aesthetic appeal
  • Easy workability
  • Excellent heat dissipation
  • High strength-to-weight ratio
  • Recyclable

Applications of 6063 Aluminum

Window and door frames

As suggested earlier, aluminum 6063 is mostly used in architectural designs.

This accounts for most of its applications, which includes its use in creating:

  • Furniture
  • Window and door frames
  • Lighting fixtures
  • Curtain walls
  • Solar panels
  • Architectural extrusions

Beyond the following, it is suitable for manufacturing car frames and other parts of automobiles, etc.

6061 vs 6063 Aluminum: Detailed Comparison

This section will take a more robust approach to the differences between 6061 and 6063 aluminum alloys. Let’s get right into it.

Material Properties Differences Between 6061 and 6063 Aluminum

Both alloys contain other elements – metals and non-metals – that help improve the physical, mechanical, and entire material properties. However, some variation in these characteristics still exists – we will examine them under the headings below.

1. Element Composition

Since alloys belong to the same series of aluminum alloys, they share similar constituting elements. However, there is a variation in the percentage of the individual components.

Either alloy contains specific amounts of magnesium and silicon, but other elements like copper and zinc may be in varying amounts.

The table below expresses the constituting elements for the two aluminum alloys, showing their quantities.

ElementAluminum 6061Aluminum 6063
Aluminum97.9 %98.5 %
Magnesium1.0 %0.45 %
Silicon0.6 %0.2 %
Copper0.15 to 0.4 %0 to 0.10 %
Zinc0 to 0.25 %0 to 0.10 %
Manganese0 to 0.15 %0 to 0.10 %
Iron0 to 0.7 %0 to 0.35 %
Titanium0 to 0.15 %0 to 0.10 %
Chromium0.04 to 0.35 %0 to 0.10 %

Observing this table, it is clear that the allies contain similar elements, though the amounts may vary. In fact, the trace elements don’t have a distinct quantity, so some may not even be present.

However, this slight variation plays a significant role in the properties of the metals. For example, aluminum 6061 contain more magnesium and silicon, which makes the alloy more difficult to extrude, requiring higher temperatures.

2. Corrosion Resistance

Aluminum forms a thin oxide layer upon exposure to oxygen or other oxidative conditions, protecting the metal from corrosion. The alloys retain this property – aluminum 6061 and aluminum 6063 have good corrosion resistance.

However, the 6061 variant has a slightly increased silicon and magnesium content, increasing its chances of corrosion. Therefore, aluminum 6063 has more excellent corrosion resistance than the 6061 alloys.

In addition, the variation in their resistance to corrosion is almost minimal. Therefore, the metals are suitable for similar applications. The corrosion resistance may also depend on the environment the aluminum product is exposed to.

3. Durability

Durability

Generally, both metals are highly durable, showing suitable strength that makes them ideal for vast applications. However, remember that aluminum 6061 is slightly less corrosion-resistant than the 6063 variant; we can infer that the latter is more durable.

Also, aluminum 6061 has a slightly higher tensile strength, fatigue strength, and yield strength. It may be difficult to compare their durability. As we said earlier, the environment where the metals are used may also play a crucial role in their durability.

4. Weight

Aluminum is a lightweight metal. This feature remains consistent in all its alloys. Standard aluminum has a density of 2.70 g/cm³ (0.0975 lb/in³). Aluminum 6061 maintains this density, while aluminum 6063 is slightly less dense at 2.69 g/cm³ (0.0972 lb/in³).

The difference in density may seem non-significant. However, the values show that AL 6061 is slightly heavier than 6063 and may prove more critical in large-sized products.

5. Machinability

Observing the machining properties of aluminum 6061 vs 6063, both alloys have excellent machining properties. The strength and hardness of either alloy are comparable, which accounts for their machinability.

Also, their good surface finish, smooth silvery appearance, and good chip formation make them good candidates for CNC machining operations, including drilling, turning, and milling.

However, machinists prefer to use the 6061 aluminum grade in machining and reserve the 6063 grade for extrusion purposes.

6. Weldability

Generally, aluminum has good weldability, including its various alloys. However, comparing aluminum 6061 to aluminum 6063, the latter has better weldability.

The slightly higher magnesium content in Al 6061 increases its porosity and tendency to crack. Also, 6063 aluminum is more responsive to heat. All these features give 6063 better weldabilities than their counterparts.

Strength Differences Between 6061 and 6063 Aluminum

Strength Differences Between 6061 and 6063 Aluminum

We cannot overemphasize the excellent strength-to-weight ratio of aluminum, making its strength comparable to generally stronger metals like steel. Below, we will compare 6061 vs 6063 strength.

1. Tensile Strength

The tensile strength of aluminum is about 13,000 psi (90 MPa) to 21,800 psi (150 MPa). However, the process of alloy formation involves heat treatment which increases the strength.

Since each alloy undergoes a different process, they tend to have varying tensile strength. Though 6061 vs 6063 strength is comparable.

The tensile strength of Al 6061 ranges from 40,000 psi (276 MPa) to 80,000 (552 MPa), with the T6 temper grade alloy having the highest strength.

On the other hand, aluminum 6063, which has a lesser toughness and strength than 6061, has a tensile strength ranging from 26,000 psi (180 MPa), with the more resilient variant being up to 46,000 psi (315MPa).

2. Yield Strength

The yield strength is usually lesser than the tensile strength, with pure aluminum having values ranging from 4,000 psi (27 MPa) to as high as 20,000 psi (138 MPa) when in complete cold-worked condition.

The yield strength of aluminum 6061 ranges from 8,700 psi (60 MPa) to 36,000psi (250 MPa). Those of Al 6063 range from 9,400 psi to (65 MPa) to 29,000 psi to (200 MPa) with the hardened aluminum variants of each alloy grade having higher values.

Ability to Form

Ability to Form

We have established that aluminum 6061 is slightly more rigid than the 6063 variant. Therefore, you may think 6063 has a better ability to form. Let’s take a more detailed approach to the alloy’s forming ability.

1. Formability

Aluminum has excellent formability, which is predominant in either alloy. After all, they contain high amounts of metal. However, aluminum 6063 has better formability than 6061.

It is easier to mold and create complex structures and shapes. Also, it has a lesser melting point. These features make aluminum 6063 the more ideal alloy for extrusions.

2. Melting Point

Compared to other metals, like iron, copper, steel, etc., pure aluminum has a low melting point of – 1220 degrees Fahrenheit. The alloys also follow suit having similar melting points, with Al 6061 – 1080 to 1202 degrees and Al 6063 – Al 606s melts at 1139 degrees.

Appearance and Touch

Appearance and Touch

Aluminum has a fine appearance – silver colored, and smooth touch. Let’s observe for any variation in the appearance and feel of aluminum 6061vs 6063.

1. Color

Either aluminum alloy presents the silver-gray color, with a mantle finish with very smooth surfaces that make them suitable for finishes such as anodizing. However, since Al 6061 contains more silicon, it may have a smoother and more appealing surface.

2. Hardness

Aluminum is a relatively soft metal; the same applies to its alloys. However, the alloying elements and the processing may determine the hardness of a particular alloy.

While aluminum 6061 has a hardness of about Brinell 60 to 95, Al 6063 measures around 55 to 75. Therefore, the former appears relatively more complex than the latter.

Conductivity Differences Between 6061 and 6063 Aluminum

Electrical Conductivity

Typical for metals, aluminum is an excellent conductor of heat and electricity. It is lightweight, making it a popular choice in transmission lines over more conductive metals like copper.

1. Electrical Conductivity

At room temperature, the electrical conductivity of aluminum is about (35 to 37) x 107 S/m. However, this value may vary for the two alloys, but we suspect they are closely related, having little effect on their conductivity.

In fact, silver, copper and gold are the notable metals with more excellent conductivity than silver. However, aluminum remains a popular choice in electronics and electrical applications because of its cost and increased density.

2. Thermal Conductivity

Like other properties we have discussed, aluminum alloys 6061 and 6063 shares similar thermal conductivity. However, the 6063 slightly has better conductivity. This suggests the reason for its relatively lower melting point. It also responds to heat which affords it better weldability and formability.

Pricing and Options

Aluminum is generally a cost-effective metal. The low-cost accounts for one of the reasons for its everyday use in various manufacturing and industrial uses.

However, the aluminum 6061 is slightly more expensive due to its relatively superior mechanical properties and applications. The cost may vary depending on location, market conditions, the alloy’s quality, supplier, etc.

Generally, aluminum 6061 sheets sell at 2 to 4 dollars per pound, while the less expensive alloy (6063) costs about 1.2 to 3.5 dollars per pound. Note that this is just a rough estimate to give you an insight into the cost, depending on your intended fabrication.

Moreover, remember that each alloy exists in different variants. Therefore, there may be some cost variations among the temper grade of the alloys.

6061 vs 6063 Aluminum: Which One to Choose?

6061 vs 6063 Aluminum- Which One to Choose

Having read this article, you’ll understand that either of these alloys is an excellent fit for your project. Being members of the same aluminum class – 6xxx series, they share close similarities, though they still have some distinctions between them.

However, you need to consider your intended application before choosing either alloy for your fabrication.

You juxtapose the characteristics of the alloy with what your product will be used for. That way, you reduce the difficulty in choosing the ideal alloy for your fabrication.

Generally, Al 6061 is preferred for manufacturing and machining parts for the aerospace and  automotive industries, shipbuilding, and manufacturing of other structural components.

On the other hand, Al 6063 is known as the go-to aluminum alloy for architectural designs, including  window and door fittings, lighting fixtures, etc.

Moreover, the 6063 alloy is more appropriate for manufacturing processes requiring high temperatures because of its better thermal conductivity.

Kemal: Manufacturing Metal Parts and Prototypes for You

Kemal- Manufacturing Metal Parts and Prototypes for You

Beyond understanding the characteristics and the one most suitable for your fabrication, you must partner with an expert manufacturer to ensure a successful project.

Kemal is an expert in CNC machining, aluminum extrusion, sheet metal fabrication, die casting, injection molding and other manufacturing processes.

Whether you need custom fabrication or intend to reengineer a rare and overly complicated structure, we are your best bet.

Our industry-standard facility comprises highly experienced and skilled professionals with the latest technologies. So you can be assured that your project will even surpass your expectations. We offer instant quotation and on-demand manufacturing services at competitive pricing. Contact us – Kemal!

Conclusion

Whether the pure metal or its alloy, aluminum remains one of the most used metals in manufacturing and construction because of its favorable properties. Alloys, such as the 606 6063 aluminum alloy, contain other elements like magnesium, silicon and copper in trace amounts to improve the already excellent features of the metal.

Compared to pure aluminum, the alloys have enhanced mechanical properties. Therefore, you can use either of these alloys for your manufacturing needs. However, when you doubt which alloy or material to use for your fabrication, contact us.

FAQs

The choice of a better alloy depends on the application. Remember that the alloys are closely related, with just a few distinctions in their properties.

However, they have some differences, making selecting either for your fabrication easier.

For example, 6063 is the better alloy for aluminium extrusion, while 6061 is better for CNC machining.

As we mentioned earlier, there are just a few distinctions in the overall properties of these two alloys.

However, aluminum 6061 is slightly stronger. It has a higher melting point, hardness and yield strength. However, the 6063 alloy has better corrosion resistance.

Indeed, either alloy possesses excellent machining properties, but aluminum 6061 is superior because of its relatively improved mechanical characteristics.

Moreover, engineers tend to restrict Al 6063 for extrusion purposes.

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