What is aluminum alloy tubing?

Choosing the right tubing for your project feels complicated, doesn't it? Using the wrong material can lead to failures, extra costs, and delays. Understanding aluminum alloy tubing helps you select wisely.

Aluminum alloy tubing is simply a hollow tube made from aluminum mixed with other elements. These added elements, like magnesium, silicon, or zinc, make the tubing stronger, more resistant to rust, or easier to work with compared to tubing made from pure aluminum.

Here at SWA Forging, we specialize in forged aluminum rings and discs, but we work extensively with different aluminum alloys¹ like 6061². We know how important it is for our customers – both traders and machining companies – to understand the materials they use. Even if you're using tubing instead of forgings, knowing the alloys is key. Let's explore aluminum alloy tubing further.

What is the difference between aluminum and alloy?

You probably hear the words "aluminum" and "aluminum alloy" used a lot. Do they mean the same thing? It can be confusing, and assuming they are identical might lead you to choose a material that isn't strong enough for your needs.

The difference is simple: pure aluminum is just the chemical element, Aluminum (Al). An aluminum alloy is a mixture. It starts with aluminum as the main ingredient, but small amounts of other elements like copper, magnesium, silicon, or zinc are deliberately added to improve its properties.
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Dive Deeper Paragraph: Why Mix Things Up?

Pure aluminum itself is a useful metal. It's very lightweight, naturally resistant to corrosion (rust) because it forms a protective oxide layer, and it conducts heat and electricity well. However, pure aluminum is also quite soft and not very strong. For many jobs, especially those needing structural integrity or durability, pure aluminum just isn't tough enough.

This is where alloying comes in. By mixing in other metals or elements, we can change aluminum's properties dramatically. Think of it like baking – adding different ingredients changes the final cake. Here are some common alloying elements and their effects:

• Magnesium (Mg): Increases strength, improves corrosion resistance (especially in saltwater), makes it easier to weld. Alloys like 5xxx series use Mg.
• Silicon (Si): Lowers the melting point, improves casting ability. When combined with Magnesium (like in our familiar 6061 alloy), it allows the alloy to be heat-treated for significant strength increases.
• Copper (Cu): Greatly increases strength and hardness, especially after heat treatment. However, it can reduce corrosion resistance. Alloys like the 2xxx series use Cu (often found in aerospace).
• Zinc (Zn): Creates the highest strength aluminum alloys when combined with Mg (like the 7xxx series, e.g., 7075). Often used in aerospace and high-stress parts.
• Manganese (Mn): Provides a moderate increase in strength and improves strain hardening. The 3xxx series uses Mn.

At SWA Forging, we work primarily with alloys like 6061 because our clients need the strength and reliability that comes from alloying and, often, specific heat treatments like T6. Pure aluminum wouldn't work for the large forged rings and discs used in demanding industrial applications.

What are the different types of aluminum tubing?

So you need aluminum tubing, but see options like extruded, drawn, round, square... feeling lost? Choosing the wrong type can mean poor performance, higher costs, or a part that doesn't fit right. It helps to know the main categories.

Aluminum tubing varies based on how it's made (like extruded or drawn), its shape (round, square, rectangular), and the specific aluminum alloy used (like 6061 or 6063). Each combination is suited for different tasks, from structural support to decorative trim.

Dive Deeper Paragraph: Manufacturing, Shapes, and Alloys

Let's break down the common types of aluminum tubing:

1. Manufacturing Method:

• Extruded Tubing³: This is the most common and generally most cost-effective type. Hot aluminum billet is forced through a die shaped like the desired tube profile (including the hollow center). It's great for standard shapes and applications where ultra-high precision isn't the top priority. Think window frames or architectural trim.
• Drawn Over Mandrel (DOM) Tubing: This process often starts with an extruded tube 'shell'. The shell is then pulled (drawn) through a die while a mandrel controls the inside diameter. This results in much tighter dimensional tolerances (wall thickness, diameter), a smoother surface finish, and often increased strength due to 'cold working'. Our machining clients often prefer DOM tubing when precision is critical for their parts.
• Seamless vs. Welded: Extruded and DOM tubing are typically seamless (no weld seam). Structural tubing might sometimes be formed from a flat sheet and welded, which can be cheaper but the seam might be a point of weakness or concern for some applications.
  2. Shape:
• Round: The classic tube shape, good for fluid transfer and structural efficiency.
• Square/Rectangular: Often used for structural framing, racks, machine guards, and architectural designs. Easier to join than round tubes sometimes.
• Custom Profiles: Aluminum's extrudability allows for complex, custom shapes tailored to specific functions, like heat sinks or specialized tracks.
  3. Alloy Grade: Different alloys (like 6061, 6063, 7075, 3003) are used depending on the required strength, corrosion resistance, finish, and cost. We'll look at 6061 vs 6063 next. Traders we work with often need to stock various types to meet diverse customer demands.

What is the difference between 6061 and 6063 aluminum tubing?

Trying to decide between 6061 and 6063 aluminum tubing for your project? They sound similar, but using the wrong one could mean your part isn't strong enough, or the finish isn't as nice as you expected. Understanding their key differences is crucial.

Basically, 6061 aluminum tubing⁴ is stronger and better for structural or machining uses. 6063 aluminum tubing⁵ is not as strong but has a much better surface finish and is easier to form into complex shapes, making it ideal for windows, doors, and architectural applications.

Dive Deeper Paragraph: Comparing Two Popular Choices

Both 6061 and 6063 are popular alloys from the 6xxx series, meaning their main alloying elements are Magnesium (Mg) and Silicon (Si). This combination allows them to be heat-treated (like to the common T6 temper) to increase strength. However, the slight differences in their composition lead to different characteristics:

As manufacturers of 6061 forged products, we know its reliable strength well. Our machining clients often use 6061 tubing for parts needing durability and good machining behavior. Traders supplying the construction or architectural markets might handle more 6063 due to its excellent finish and extrudability. If you need strength above all, 6061-T6 is usually the better choice between these two. If appearance and complex shape are key, 6063 is often preferred.

What is 7075 Aluminium alloy grade?

Need aluminum tubing that can handle really high stress? Standard alloys like 6061 might not be strong enough for demanding applications. Using an under-spec alloy could lead to failure when the part is put under load.

7075 aluminum⁶ is a very high-strength aluminum alloy. It gets its strength mainly from zinc added to the mix. It's one of the strongest aluminum alloys available, comparable to some steels in strength but much lighter, commonly used in aircraft and performance equipment.

Dive Deeper Paragraph: The High-Strength Option

7075 belongs to the 7xxx series of aluminum alloys, which use Zinc (Zn) as the primary alloying element, often combined with Magnesium (Mg) and Copper (Cu). This specific recipe allows 7075, especially in the T6 temper (solution heat-treated and artificially aged), to achieve very high mechanical properties:

• Strength: Its yield and tensile strengths are significantly higher than 6061-T6, often nearly double. This makes it suitable for applications experiencing high stress or requiring maximum strength with minimum weight.
• Strength-to-Weight Ratio: This is where 7075 truly shines. It offers strength levels approaching some steels but at only about one-third the weight. This is critical for aerospace and performance applications.
• Hardness: It's also considerably harder than 6061, providing better resistance to wear and deformation.

However, these benefits come with trade-offs:

• Corrosion Resistance: Generally lower than 6xxx series alloys like 6061 or 6063. 7075 parts often need protective coatings like anodizing or paint, or they might use 'alclad' versions (a thin layer of pure aluminum bonded to the surface).
• Weldability: Considered poor. Welding 7075 is difficult and often results in significant loss of strength in the heat-affected zone. Mechanical fasteners (bolts, rivets) are usually preferred.
• Formability: Less formable than 6xxx alloys. Bending or shaping can be more challenging.
• Cost: Generally more expensive than 6061 or 6063 due to the alloying elements and processing.

Typical applications include aircraft structural components (like wing spars), high-end bicycle frames and components, molds for the plastics industry, rock climbing gear, and military applications. While SWA Forging focuses on alloys like 6061, understanding high-performance options like 7075 helps us appreciate the spectrum of materials our clients might encounter or require for specialized projects.

Conclusion
Aluminum alloy tubing uses added elements for better properties than pure aluminum. Types vary by production, shape, and alloy like strong 6061, finish-focused 6063, or high-strength 7075.