What is Aluminum Tubing Used For, and Why is it So Popular?

You see aluminum tubing¹ everywhere, from simple household items to complex industrial structures. But what makes this material so versatile and widely adopted across so many different applications? Choosing the wrong material can lead to inefficiencies or even failures.

Aluminum tubing is used for a vast array of applications due to its excellent strength-to-weight ratio, corrosion resistance, and ease of fabrication. Common uses include structural frames, fluid conveyance, heat exchangers, and architectural elements.

As a company, SWA Forging, specializing in aluminum alloy forged rings and discs since 2012, we work extensively with various aluminum alloys. While our primary products are forged components for traders and machining companies, we deeply understand the inherent qualities of aluminum that make it suitable for diverse forms, including tubing. The principles of material strength, corrosion resistance, and customization we apply to our forgings are equally relevant to understanding the widespread use of aluminum tubing. Let's explore its applications and characteristics.

How to connect aluminum tubing together?

You have your aluminum tubes, but now you need to join them to create your structure or system. What are the best ways to connect aluminum tubing effectively and securely? The wrong connection can compromise the entire assembly.

Aluminum tubing can be connected using various methods including welding (TIG or MIG), mechanical fasteners (bolts, rivets, screws), specialized connectors and fittings (couplings, clamps), or structural adhesives. The best method depends on the application, strength requirements, and alloy.

Connecting aluminum tubing properly is crucial for the integrity of any assembly. The choice of method often depends on the specific aluminum alloy, the required strength of the joint, whether the joint needs to be permanent or removable, and the tools available.
Here are common methods:

• Welding: TIG (Tungsten Inert Gas) welding is very common for aluminum, providing clean, strong welds. MIG (Metal Inert Gas) welding can also be used, especially for thicker sections, and is generally faster. Heat-treatable alloys (like 6061-T6) will lose some strength in the heat-affected zone (HAZ) of the weld, which might require post-weld heat treatment or designing for the reduced strength.
• Mechanical Fasteners: This is a straightforward method using bolts, screws, or rivets. It often requires drilling holes. This method is great for creating demountable joints or when welding isn't feasible or desired. It's important to choose fasteners compatible with aluminum to avoid galvanic corrosion, especially in moist environments.
• Specialized Connectors and Fittings: Many systems use proprietary or standard connectors, like push-to-connect fittings for pneumatic lines, clamps, or structural pipe fittings (often slip-on types secured with set screws). These can make assembly quick and easy without specialized tools like welders.
• Structural Adhesives: Modern adhesives can create very strong and durable bonds between aluminum tubes, distributing stress evenly and often providing good environmental sealing. Surface preparation is critical for a good adhesive bond.
  I recall a machining client who was building a lightweight frame for some automated equipment. They opted for specialized mechanical connectors for their 6061 aluminum tubing because it allowed for easy assembly, disassembly, and adjustments on-site without needing welding expertise.

What is aluminum square tubing used for?

You've seen square aluminum tubes and wonder about their specific uses. Why choose a square profile over a round one, and where does it excel? Understanding its advantages helps in material selection.

Aluminum square tubing is widely used for structural frames, supports, machine guarding, furniture, architectural trim, and display stands. Its flat surfaces make connections and mounting easier, providing good structural integrity and a clean aesthetic.

Aluminum square tubing is incredibly versatile due to its shape and the inherent properties of aluminum. Its flat surfaces offer several advantages over round tubing in certain applications:

• Ease of Connection: It's generally easier to make straight cuts and join square tubes using simple butt joints, miter joints, or by using flat brackets and fasteners. Welding square tubes can also be more straightforward in terms of alignment.
• Mounting Surfaces: The flat sides provide convenient surfaces for mounting panels, components, or other fixtures directly.
• Structural Efficiency: For bending loads applied perpendicular to a flat side, square tubing can offer good resistance due to its shape. It's often used in applications where loads are predictable.
• Aesthetics: Square tubing can provide a modern, clean look for architectural elements, furniture, and display fixtures.

Common applications include:

• Framework: Building frames for machinery, workbenches, shelving units, and enclosures.
• Architectural Uses: Window and door frames, railings, decorative trim, and support structures for canopies or facades.
• Furniture: Legs and frames for tables, chairs, and other lightweight furniture.
• Display Systems: Booths for trade shows, retail displays, and signage.
• DIY Projects: Its ease of use makes it popular for various home and workshop projects.
  We often see machining companies we supply with our forged aluminum discs using square aluminum extrusions (tubing is a type of extrusion) for building the support structures and enclosures for the machines they build or modify. The ease of fabrication with square profiles saves them time and effort.

What is the strongest aluminum tubing?

You need maximum strength from your aluminum tubing. Which alloy and type should you look for to ensure it can handle the highest loads? Making the wrong choice could lead to structural failure.

The "strongest" aluminum tubing typically comes from the 7xxx series alloys (like 7075) in a T6 temper. Strength also depends on wall thickness and profile. However, "strongest" must be balanced with other needs like corrosion resistance or cost.

When we talk about the strongest aluminum tubing², we usually refer to its tensile strength and yield strength. Several factors contribute to this:

1. Alloy Choice:
   • 7xxx Series (e.g., 7075, 7050): These alloys, primarily alloyed with zinc, are the highest-strength aluminum alloys available. In a T6 temper (solution heat-treated and artificially aged), 7075 can achieve tensile strengths comparable to some mild steels, but at about a third of the weight. These are often used in aerospace and high-performance sporting equipment where strength-to-weight ratio is paramount.
   • 2xxx Series (e.g., 2024): Alloyed with copper, these also offer very high strength, especially at elevated temperatures compared to 7xxx series. They are also common in aerospace.
   • 6xxx Series (e.g., 6061-T6): While not as strong as the 7xxx or 2xxx series, 6061-T6 offers excellent strength for its versatility, good corrosion resistance, and lower cost. It's often strong enough for many structural applications.
2. Temper: The heat treatment condition (temper) is crucial. For heat-treatable alloys, the T6 temper (solution heat-treated and artificially aged) generally provides the highest strength.
3. Wall Thickness and Profile: For a given alloy and temper, a tube with a thicker wall will naturally be stronger and more resistant to bending and buckling. The shape of the tube (round, square, rectangular) also influences its structural efficiency under different types of loads.
   It's important to note that the "strongest" isn't always the "best." High-strength alloys like 7075 can be more susceptible to stress corrosion cracking in certain environments and are generally more expensive and harder to weld than 6061. The selection always involves trade-offs based on the specific application's requirements.

Is 6061 aluminum stronger than stainless steel?

You're comparing materials and need to know how 6061 aluminum³ stacks up against stainless steel in terms of strength. This is a common point of confusion, as both are seen as robust materials.

No, generally, common grades of stainless steel (like 304 or 316) have higher tensile and yield strength than 6061-T6 aluminum. However, 6061-T6 has a significantly better strength-to-weight ratio, meaning it's stronger for its weight.

This question requires a nuanced answer because "stronger" can be interpreted in different ways, and there are many grades of both aluminum and stainless steel. Let's compare typical 6061-T6 aluminum with a common stainless steel like 304:

• Tensile Strength:
  • 6061-T6 Aluminum: Typically around 45,000 psi (310 MPa).
  • 304 Stainless Steel: Typically around 75,000 - 90,000 psi (515 - 620 MPa).
    In absolute terms of tensile strength, 304 stainless steel is significantly stronger.
• Yield Strength (the point at which material begins to deform permanently):
  • 6061-T6 Aluminum: Typically around 40,000 psi (276 MPa).
  • 304 Stainless Steel: Typically around 30,000 - 40,000 psi (205 - 275 MPa) in its annealed state, but can be much higher when cold-worked. Some grades are significantly higher.
    Yield strength can be closer, but stainless steel often maintains an edge or can be processed to have higher yield strength.
• Density (Weight):
  • Aluminum (6061): Approx. 2.70 g/cm³.
  • Stainless Steel (304): Approx. 8.00 g/cm³.
    Stainless steel is nearly three times denser than aluminum.
• Strength-to-Weight Ratio: This is where aluminum shines. Because it's so much lighter, 6061-T6 offers more strength per unit of weight compared to 304 stainless steel. This is why aluminum is favored in applications where weight saving is critical, like aerospace, automotive, and portable structures.
  So, if you need the highest absolute strength and weight is not a primary concern, stainless steel might be better. If weight is a critical factor and you need good strength, aluminum is often the superior choice. Other factors like corrosion resistance in specific environments, cost, and machinability also play a big role in material selection.

What is the most common aluminum tubing?

You're looking for a general-purpose aluminum tube and want to know what's most readily available and widely used. Knowing the common types helps in sourcing and design for many standard applications.

The most common aluminum tubing alloys are 6061 and 6063. 6061-T6 is popular for structural applications needing good strength, while 6063 is favored for architectural applications due to its excellent surface finish and corrosion resistance.

When it comes to general availability and widespread use, two aluminum alloys stand out for tubing:

1. 6061 Aluminum:
   • Properties: This is a precipitation-hardening alloy known for its good strength (especially in the T6 temper), good weldability, good machinability, and good corrosion resistance.
   • Common Tempers: Often found in T6 (solution heat-treated and artificially aged) for maximum strength, but also available in T4 (solution heat-treated and naturally aged) or annealed (O) states.
   • Applications: Widely used in structural applications, frames, machine parts, automotive components, marine fittings, and bicycle frames. It's a true workhorse alloy. Many of our clients who order forged aluminum rings and discs from us at SWA Forging for industrial machinery often also use 6061 tubing for associated frameworks due to its reliable properties and availability.
2. 6063 Aluminum:
   • Properties: This alloy has slightly lower strength than 6061 but offers excellent extrudability (meaning it can be easily formed into complex shapes), a superior surface finish, and very good corrosion resistance, especially to atmospheric conditions.
   • Common Tempers: Often found in T5 (cooled from an elevated temperature shaping process and then artificially aged) or T6 tempers.
   • Applications: Predominantly used for architectural applications like window and door frames, curtain walls, railings, trim, and irrigation tubing. Its smoother surface also makes it ideal for applications requiring anodizing for color or enhanced protection.
     While other alloys are used for specialized tubing (e.g., 7075 for high-strength aerospace tubes, or 3003 for good formability and corrosion resistance in heat exchangers), 6061 and 6063 cover the vast majority of common tubing needs due to their balanced properties, cost-effectiveness, and wide availabili