Skip to content 
Confused about what exactly aluminum alloy tubes1 and bars are? Not understanding these common forms can make selecting the right material for your project difficult. They are fundamental building blocks in many industries.
Aluminum alloy tubes are hollow cylindrical (or other profile) products, while aluminum alloy bars are solid products, typically round, square, or rectangular in cross-section. Both are made from aluminum mixed with other elements to enhance properties.
Aluminum alloy tubes and bars are everywhere. You see them in construction, in machinery, in transportation, and so much more. Here at SWA Forging, while we specialize in large-diameter forged rings and discs, the fundamental aluminum alloys we work with are the same ones that go into making these versatile tubes and bars. Our clients, both traders and machining companies, frequently handle these forms, so understanding them is important. Let's take a closer look.
What alloy is an aluminum tube?
Wondering what specific aluminum alloy makes up a tube? Choosing a tube without knowing its alloy can lead to performance issues or incompatibility. Tubes can be made from various alloys depending on the intended use.
Aluminum tubes are commonly made from alloys like 6061 (for structural use and good machinability), 6063 (for architectural applications and good finish), 3003 (for good formability and corrosion resistance), and 5052 (for good marine corrosion resistance).
When you pick up an aluminum tube, the actual "metal" it's made from is an aluminum alloy. Pure aluminum is often too soft for many applications, so other elements are added to improve things like strength, corrosion resistance, or machinability. The specific alloy used for a tube really depends on what the tube will be used for.
For example, 6061 aluminum alloy is a very popular choice for tubes. It offers a great combination of strength, weldability, and corrosion resistance. You'll find 6061 tubes in structural applications like frames, supports, and also in many machined parts. Many of our machining customers appreciate 6061 for its good characteristics after we supply them with forged 6061 blanks that they might machine down.
Another common one is 6063 aluminum alloy. This alloy is often called an "architectural alloy" because it has a very good surface finish and is excellent for anodizing, which is a process to give aluminum a durable and decorative coating. So, you'll see 6063 tubes in window frames, door frames, railings, and trim.
Then there's 3003 aluminum alloy. This alloy is known for its good workability and corrosion resistance. It's not as strong as 6061 or 6063, but it can be easily formed, bent, and welded. You might find 3003 tubes in applications like heat exchangers or general sheet metal work that's been formed into a tube.
For environments with saltwater, 5052 aluminum alloy is often preferred for tubes due to its superior resistance to marine corrosion.
The choice of alloy directly impacts how the tube will perform, so it’s crucial to select one that matches the application's demands.
What is an aluminum tube?
It seems simple, but what exactly defines an aluminum tube for technical purposes? A basic understanding might not cover its key characteristics and how it's made. An aluminum tube is more than just a hollow pipe.
An aluminum tube is a hollow extruded or drawn product made from an aluminum alloy, available in various cross-sectional shapes (round, square, rectangular, oval) and sizes. It's valued for its light weight, strength-to-weight ratio, and corrosion resistance.
An aluminum tube, at its core, is a long, hollow piece made from an aluminum alloy. The key word here is "hollow." This hollow structure is what gives tubes many of their useful properties, especially a good strength-to-weight ratio. They can be strong without being overly heavy.
Most aluminum tubes are produced by a process called extrusion. In extrusion, a heated aluminum billet (a solid block of aluminum) is forced through a die with an opening shaped like the desired tube profile. Imagine squeezing toothpaste out of a tube – it's a similar concept but with metal and much higher forces. This process allows for a wide variety of shapes, not just round tubes. You can get square tubes, rectangular tubes, oval tubes, and even more complex custom profiles.
Sometimes, for tighter tolerances or specific mechanical properties, tubes can be further processed by drawing. Drawn tubes are pulled through a die to reduce their diameter and wall thickness, which can improve surface finish and dimensional accuracy.
The characteristics of an aluminum tube depend on the alloy used and how it's made (its temper). Generally, they are:
- Lightweight: Aluminum is about one-third the density of steel.
- Corrosion Resistant: Aluminum naturally forms a protective oxide layer.
- Good Strength-to-Weight Ratio: Especially with certain alloys and tempers.
- Easy to Fabricate: They can be cut, bent, welded, and machined.
- Recyclable: Aluminum can be recycled repeatedly without losing quality.
These properties make aluminum tubes incredibly versatile for countless applications. While SWA Forging focuses on solid forged rings and discs, the aluminum we supply often gets machined by our customers into various components, and understanding basic forms like tubes is part of the broader material knowledge in our industry.
What are aluminium bars used for?
You see aluminum bars, but what are their typical jobs? Not knowing their uses might mean overlooking them for a suitable application. Aluminum bars are versatile and found in many structural and machined components.
Aluminum bars are used for a wide range of applications, including structural components (frames, supports, braces), machining stock for creating parts, architectural elements (trim, railings), and electrical conductors (busbars due to good conductivity).
Aluminum bars, which are solid pieces of aluminum alloy (unlike hollow tubes), come in various shapes like round, square, rectangular (often called flat bars), and hexagonal. Their uses are just as varied as their shapes, thanks to aluminum's beneficial properties.
One major area is machining stock. Many of our clients who are machining companies will purchase aluminum bar – or sometimes they machine bar-like sections from the forged discs we supply – to create custom parts. The good machinability of many aluminum alloys, like 6061 or 7075, makes them ideal for CNC machining into complex components for machinery, automotive parts, or electronic enclosures. I’ve seen some incredibly intricate parts made from aluminum bar stock.
In structural applications, aluminum bars are used to build frames, supports, braces, and lattices. Their high strength-to-weight ratio is a big advantage here, especially in transportation (like truck beds or trailers) or in temporary structures where ease of handling is important.
Architectural uses are also common. You'll find aluminum flat bars used for trim, decorative elements, kick plates, and even as part of railing systems. The corrosion resistance of aluminum and its ability to be anodized for different colors make it attractive for these visible applications.
Another important, though more specialized, use is in electrical applications. Certain aluminum alloys, particularly from the 1xxx series (like 1350), have excellent electrical conductivity. These are used to make busbars, which are solid metallic strips or bars used for power distribution in switchgear, panel boards, and substations.
The specific alloy of the bar will dictate its suitability for these uses. For instance, a high-strength 7075 bar might be used for a critical stressed component, while a 6063 bar might be chosen for an architectural feature needing a good anodized finish.
What are the two types of Aluminium alloys?
Heard about different aluminum alloy types but find it confusing? This can make it hard to understand material specifications. Aluminum alloys are broadly divided into wrought and cast categories based on how they're made.
The two primary classifications of aluminum alloys are wrought alloys, which are shaped by mechanical working (like forging, rolling, extrusion), and cast alloys, which are formed by pouring molten metal into molds.
When we talk about aluminum alloys, they are generally grouped into two main families based on their initial production method. This fundamental difference affects their properties and how they are designated. At SWA Forging, we exclusively work with wrought aluminum alloys2 because the forging process itself is a form of mechanical working that enhances the material's properties.
-
Wrought Aluminum Alloys:
- How they're made: These alloys are shaped by mechanical deformation processes like rolling (to make sheet or plate), extrusion (to make profiles, tubes, and bars), drawing (to make wire), or forging (to make strong, discrete parts like our rings and discs).
- Characteristics: The mechanical working refines the grain structure, closes up internal porosity, and generally leads to higher strength, better ductility, and improved fatigue resistance compared to cast alloys.
- Designation: They are typically identified by a four-digit numbering system. The first digit indicates the principal alloying element(s):
- 1xxx series: Pure aluminum (99.00% or greater)
- 2xxx series: Copper
- 3xxx series: Manganese
- 4xxx series: Silicon
- 5xxx series: Magnesium
- 6xxx series: Magnesium and Silicon
- 7xxx series: Zinc
- Most aluminum tubes and bars you encounter are made from wrought alloys.
-
Cast Aluminum Alloys:
- How they're made: These alloys are produced by melting the aluminum and alloying elements and then pouring the molten metal into a mold to solidify into the desired shape. Common casting methods include sand casting, die casting, and permanent mold casting.
- Characteristics: Casting is excellent for producing complex and intricate shapes, often close to the final desired form (near-net shape), which can reduce machining costs. However, cast products can sometimes have internal porosity and generally have lower tensile strength and ductility than their wrought counterparts.
- Designation: Cast alloys often use a three-digit system with a decimal point (e.g., 356.0, A380.0). The first digit also indicates the main alloy group, but the series numbers don't directly correspond to the wrought series for the same alloying elements.
Understanding this distinction is key because the properties and applications of wrought alloys (used for most tubes, bars, and our forgings) differ significantly from cast alloys.
Conclusion
Aluminum alloy tubes and bars are essential industrial materials. They come from various alloys, mostly wrought, and are valued for their light weight, strength, and versatility in numerous applications.
