Why is Round Aluminum Tubing a Go-To for So Many Projects?

Need a versatile, lightweight yet strong material? Agitation: Solid bars are heavy and often overkill. Solution: Round aluminum tubing offers an ideal blend of strength, formability, and material efficiency.

Round aluminum tubing¹ is a hollow, cylindrical product made from various aluminum alloys². It's highly valued for its excellent strength-to-weight ratio, natural corrosion resistance, and how easily it can be fabricated for diverse applications.

Here at SWA Forging, we primarily manufacture large-diameter forged aluminum rings and discs. However, aluminum, in all its forms, is a fascinating material. Many of our clients, especially traders and machining companies, deal with various aluminum products, including tubing. So, understanding its properties and uses is important across the industry. I've seen it used in so many innovative ways; it's truly a remarkable product.

How Do You Connect Round Aluminum Tubing?

Joining tubes seems complex or messy. Agitation: Welding needs special skills, and fasteners can look bulky. Solution: Several effective methods exist, from welding to specialized mechanical connectors.

Round aluminum tubing can be connected by welding (TIG or MIG is common), using mechanical fasteners like bolts or rivets, employing specialized connectors such as couplings or clamps, or even with structural adhesives, depending on the application's demands.

Exploring Connection Methods for Aluminum Tubing

Choosing the right way to connect round aluminum tubing is key for structural integrity and appearance. The best method depends on the alloy, application, required strength, and available tools.

Common Connection Techniques

• Welding:
  • TIG (Tungsten Inert Gas) Welding: This is often preferred for aluminum as it produces clean, high-quality welds. It gives the welder good control. It's great for visible joints or when strength is critical.
  • MIG (Metal Inert Gas) Welding: MIG welding is generally faster than TIG and can be easier for thicker materials. It's good for production runs.
    It's important to note that not all aluminum alloys are equally weldable. For instance, 6xxx series alloys weld well, but 7xxx series high-strength alloys can be challenging.
• Mechanical Fasteners:
  • Bolts and Screws: These are straightforward for creating demountable joints. You just drill holes and fasten. This is common in framework and temporary structures.
  • Rivets: Rivets create strong, permanent joints and are good for resisting vibration. They are often used in aerospace and automotive applications.
• Specialized Connectors: There's a huge range of off-the-shelf connectors. These include internal expanding connectors, external clamps, slip-on fittings, and modular systems. These often require minimal tools and can be very quick for assembly. Many of our machining clients might prepare tube ends (e.g., by precision cutting or adding grooves) to work with these specialized fittings.
• Adhesives: Modern structural adhesives can create very strong and durable bonds between aluminum tubes. Surface preparation is critical for good adhesion. Adhesives distribute stress evenly and can join dissimilar materials.

The choice often comes down to a balance of strength, cost, ease of assembly, and aesthetics.

What is the Difference Between Aluminum Pipe and Aluminum Tube?

Pipe or tube – they sound alike, what's the deal? Agitation: Using the wrong one can mess up your design and fit. Solution: The key differences are in how they're measured and their typical uses.

Aluminum pipe is primarily measured by its nominal inside diameter (ID) and a "schedule" number for wall thickness; it's mainly for fluid or gas transport. Aluminum tube is measured by its exact outside diameter (OD) and specific wall thickness, usually for structural or precision applications.

Distinguishing Pipe from Tube in the Aluminum World

The terms "pipe" and "tube" are often used interchangeably in casual conversation, but in engineering and material specification, they mean different things. This is especially true for aluminum products.

Key Distinctions

1. Measurement Standard:
   • Pipe: Always measured by its Nominal Pipe Size (NPS) and Schedule (SCH). The NPS refers to a nominal, not exact, inside diameter. The schedule number (e.g., SCH 40, SCH 80) dictates the wall thickness. For a given NPS, a higher schedule number means a thicker wall and a smaller actual ID.
   • Tube: Measured by its exact Outside Diameter (OD) and a specific Wall Thickness (WT). So, a 1-inch OD tube with a 0.125-inch wall thickness will always have those exact dimensions, within manufacturing tolerances.
2. Primary Application:
   • Pipe: Designed to transport fluids or gases. Its dimensions are optimized for flow capacity and pressure ratings.
   • Tube: Used for structural purposes, mechanical parts, heat exchangers, or applications where precise dimensions and a smooth surface are important. Our machining customers often work with tubing for components that require tight tolerances.
3. Tolerances: Tubing generally has much tighter manufacturing tolerances for diameter, wall thickness, and straightness compared to pipe.
4. Shapes: Pipe is almost exclusively round. Tubing can be round, square, rectangular, or other custom extruded shapes. This article focuses on round tubing.

Here’s a simple comparison:

Understanding this difference is vital for traders supplying materials and for machining companies selecting stock for their projects.

What is the Strongest Aluminium Tube?

Need the absolute maximum strength from aluminum tubing? Agitation: Not all aluminum is created equal in toughness. Solution: Alloy choice and heat treatment (temper) are crucial for peak strength.

The strongest aluminum tube is typically made from 7000-series alloys, with 7075-T6³ being a prime example. These alloys can achieve tensile strengths comparable to some mild steels, making them ideal for high-stress, demanding applications.

Understanding High-Strength Aluminum Alloys for Tubing

When an application demands the highest possible strength from aluminum tubing, engineers turn to specific alloys and tempers. While many aluminum alloys offer a good balance of properties, some are engineered specifically for strength.

The Champions of Strength: 7000 Series

• 7075 Alloy: This is one of the most common high-strength aluminum alloys. Its primary alloying element is zinc, with smaller amounts of magnesium and copper.
  • Properties: It boasts excellent mechanical strength, particularly its tensile and yield strength. It's significantly stronger than more common alloys like 6061.
  • Temper: The -T6 temper (solution heat-treated and then artificially aged) is very common for 7075 and brings out its maximum strength. Other tempers like -T651 (stress-relieved) are also used.
  • Considerations: While very strong, 7075 can be more susceptible to stress corrosion cracking in certain environments compared to some other alloys, and its weldability is generally poor. Its formability is also lower than softer alloys.
• Other 7xxx Alloys: Alloys like 7050 or 7068 can offer even higher strength or better specific properties like fracture toughness, but 7075 remains a widely used benchmark.

Comparison with 6061-T6

For perspective, 6061-T6 aluminum, a very popular structural alloy, has a typical ultimate tensile strength around 45,000 psi (310 MPa). In contrast, 7075-T6 can reach ultimate tensile strengths of around 76,000 - 83,000 psi (524 - 572 MPa). That's a substantial increase.
Applications for such high-strength tubing include aerospace components, high-performance bicycle frames, rock climbing gear, and military equipment.
At SWA Forging, we work with various high-strength aluminum alloys for our forged products. The principles of achieving strength through alloying and heat treatment are fundamental to our work, just as they are for producing strong tubing.

What is the Difference Between 6061 and 6063 Aluminum Tubing?

Choosing between 6061 and 6063 tubing can be confusing. Agitation: They sound similar, but using the wrong one impacts performance and finish. Solution: 6061 offers superior strength, while 6063 excels in finish and corrosion resistance.

6061 aluminum tubing⁴ has higher mechanical strength and good machinability, making it suitable for structural components and machined parts. 6063 tubing has slightly lower strength but offers excellent corrosion resistance and a much smoother surface finish, ideal for architectural applications and decorative trim.

Comparing 6061 and 6063 Aluminum Tubing

6061 and 6063 are two of the most popular aluminum alloys, especially for extruded forms like tubing. They both belong to the 6xxx series, meaning their primary alloying elements are magnesium and silicon. However, subtle differences in their composition lead to distinct properties and applications.

Alloy 6061

• Composition: Contains more magnesium and silicon compared to 6063, and often a bit of copper.
• Strength: Significantly stronger than 6063, especially in the T6 temper. It's a true structural alloy.
• Machinability: Good. It can be machined to tight tolerances. Many of our machining customers at SWA Forging are familiar with working with 6061 in various forms.
• Weldability: Good.
• Corrosion Resistance: Good, though not as high as 6063.
• Finish: Surface finish after extrusion is decent, but not as smooth or bright as 6063.
• Uses: Structural applications (frames, supports), machine parts, bicycle frames, automotive components, hydraulic tubing.
  

  Alloy 6063

• Composition: Lower amounts of magnesium and silicon.
• Strength: Moderate strength, lower than 6061.
• Machinability: Fair.
• Weldability: Excellent.
• Corrosion Resistance: Excellent, particularly its resistance to atmospheric corrosion.
• Finish: Known for its excellent surface finish directly after extrusion. It's ideal for anodizing, resulting in attractive and durable decorative finishes.
• Uses: Architectural applications (window frames, door frames, curtain walls), railings, trim, irrigation tubing, heat sinks due to good thermal conductivity and extrudability into complex shapes.

Here’s a comparative table:

For traders, knowing these differences helps guide their customers. For machining companies, 6061 is often the choice for parts needing strength, while 6063 might be selected if a superior as-extruded finish is paramount and strength requirements are lower.

Conclusion

Round aluminum tubing is versatile and efficient. Choosing the right alloy, connection method, and understanding its properties ensures project success and optimal performance in many industries.