This article will take an in-depth look at aluminum tubing and piping.
The article will bring more detail on topics such as:
This chapter will cover the definition of aluminum tubing and piping, their manufacturing processes, and key factors to consider when selecting them.
Aluminum piping and tubing are characterized by their silvery-white color, softness, and ductility. As a member of the boron group, aluminum is the third most abundant element on Earth. It has a low density and, when exposed to corrosive environments, forms a protective passivating layer on its surface to prevent further corrosion of its internal structure. Typically, aluminum is alloyed with elements such as copper, manganese, zinc, magnesium, and silicon to enhance its properties.
Aluminum pipes and tubing have only about 30% of the density of copper, while still offering good electrical and thermal conductivity. Aluminum is considered a superconductor in certain conditions, as it can conduct electricity effectively at low temperatures.
Piping refers to cylindrical tubes used for transporting gases and fluids, typically with a size that only vaguely indicates the capacity of the piping system. Tubing, on the other hand, can be circular, oval, rectangular, or square, and is defined by its outer diameter and wall thickness, which are measured in millimeters or inches.
Selecting the right type of tube can be daunting, as both aluminum and stainless steel come in various alloys and tempers, each with distinct mechanical and physical properties.
The strength of materials can be quantified using Young’s modulus of elasticity, measured in force per unit area. This metric helps assess the strength of aluminum and steel tubing.
Young’s Modulus – At 70°F, the Young’s modulus of elasticity for aluminum is approximately 10 million psi, while for steel, it is around 30 million psi. This indicates that steel tubing is about three times stronger than aluminum tubing of the same dimensions.
Material Weight – Steel is roughly three times heavier than aluminum for the same size. Consequently, aluminum tubing needs to have walls that are three times thicker than those of steel tubing to match its strength, making the weight advantage of aluminum relatively minor.
Diameter – The strength of aluminum or steel tubing also varies with the diameter of the tube. A larger nominal diameter generally increases the strength of the tubing, while a smaller diameter decreases it.
Aluminum tubing and piping can be manufactured through several methods, including:
Aluminum extrusion is a procedure where the aluminum alloy metal is forced through a die of a specific cross-sectional area.
Aluminum extrusion is somewhat analogous to squeezing toothpaste from a tube. In this process, a powerful ram pushes the aluminum through a die, shaping it as it exits the die's opening. The resulting aluminum profile mirrors the shape of the die and is then drawn along a run-out table. At a basic level, the concept of aluminum extrusion is relatively straightforward.
The process is similar to the force used to squeeze toothpaste from a tube with your fingers. As you squeeze, the toothpaste emerges, taking on the shape of the tube’s opening. Here, the tube's opening functions much like an extrusion die. Just as the toothpaste takes the form of the tube's opening, aluminum takes the shape of the die. Commonly extruded shapes include round and square profiles, among others.
Displayed above are the diagrams used to create the dies. The extrusion process allows for the production of intricate shapes and profiles.
A circular die is typically crafted from H13 steel. If an appropriate die is available, it is retrieved from storage. Prior to extrusion, the die must be preheated to temperatures between 450 and 500 degrees Celsius. This preheating helps extend the die's lifespan and ensures a consistent metal flow. Once preheated, the die is ready to be installed in the extrusion press.
Next, a cylindrical block of aluminum alloy, known as a billet, is cut from a larger batch of alloy material. This billet is then placed in an oven and heated to temperatures between 400 and 500 degrees Celsius. The heating process makes the billet malleable enough for extrusion, but it does not reach a molten state.
As soon as the billet is done preheating, it is mechanically moved to the extrusion press. Before loading it onto the press, a lubrication or release agent is applied on it. The release agent is also applied on the extrusion ram, to avoid the ram and billet from sticking together.
The malleable billet is then loaded into the extrusion press, where a hydraulic ram applies 15,000 tons of pressure. This immense force pushes the billet into the extrusion press’s chamber, causing the metal to expand and conform to the shape of the container walls.
As the metal alloy fills the chamber, it is forced against the extrusion die. The sustained pressure confines the aluminum, allowing it to pass only through the openings of the die. The result is a completed pipe or tube that emerges from the die.
Once the extrusion exits the die, a puller takes hold of it and guides it along the run-out table, synchronizing with its exit speed from the press. During this process, the pipe or tube is "quenched" by cooling it consistently, either with a fan positioned above the table or through a water bath.
After the extrusion reaches its full length on the table, it is cut using a heated saw to detach it from the extrusion process. Temperature is crucial throughout the entire procedure. Even though the extrusion is rapidly cooled after exiting the press, it remains warm and hasn't fully cooled down yet.
Once cut, the extrusions are mechanically transferred from the run-out table to a cooling table. They remain there until they reach ambient temperature. After cooling, the next step involves stretching the pipes or tubes.
Natural twisting in the pipes or tubes must be corrected. This is done by moving them to a stretcher, where each piece is clamped at both ends and stretched until it is straightened and meets the required specifications.
Once the extrusion has been straightened and work-hardened, it is transferred to the saw table. Here, it is cut into predetermined lengths, typically ranging from 8 to 21 feet (2.4 to 6.4 meters). At this stage, the extrusion exhibits the T4 temper. Following the cutting process, the extrusions may be placed in an oven for aging to achieve the T6 or T5 temper.
After the extrusion process is complete, the pipes or tubes may undergo heat treatment to enhance their properties. Following this, various surface finishes are applied to boost their aesthetic appeal and provide better corrosion resistance.
Additionally, the tubing or piping might be subjected to fabrication processes to achieve their final dimensions.
Alloys from the 7000, 6000, and 2000 series can be heat treated to enhance their yield stress and tensile strength.
This enhancement is achieved by placing the piping in aging ovens, where the aging process is accelerated, resulting in T6 or T5 tempers.
How do these treatments affect their properties? Untreated 6061 aluminum (T4) has a tensile strength of 241 MPa (35,000 psi), whereas heat-treated 6061 aluminum (T6) reaches a tensile strength of 310 MPa (45,000 psi).
After heat treatment, piping is finished.
Aluminum pipes often receive various finishing treatments. The primary purposes for selecting a finishing method are to enhance the aluminum's appearance and boost its corrosion resistance.
For example, anodizing increases the thickness of the aluminum's natural oxide layer. This process not only improves corrosion resistance but also enhances wear resistance, increases surface emissivity, and provides a porous surface that can absorb dyes for different color effects.
Additional finishing techniques such as powder coating, sandblasting, painting, and sublimation (for wood-like appearances) are also available. A variety of fabrication options can be applied to extrusions to achieve desired results.
Fabrication options enable the customization of extrusions to meet specific dimensional requirements. Tubing or piping can be drilled, punched, cut, machined, and more to meet precise specifications. With a variety of techniques available, aluminum tubing can be tailored to suit any project’s needs.
The primary aluminum alloys used in pipe and tubing include 2024, 3003, 6061, 5052, and 7075. Each alloy features unique mechanical and physical properties due to their distinct alloying elements such as magnesium, manganese, copper, zinc, and silicon.
Aluminum tubes come in various sizes and are often chosen for their lightweight nature, excellent thermal and electrical conductivity, and corrosion resistance. For instance, alloys like 7075, 6061, and 2024 are preferred in aerospace applications due to their high strength-to-weight ratio and good fatigue resistance. While 7075 and 2024 offer greater strength, they are more prone to corrosion compared to the naturally corrosion-resistant and more weldable 6061. 7075 provides superior strength at a higher cost.
Alloy 3003 is suitable for applications that prioritize corrosion resistance and moderate strength over ductility. For projects that require extensive welding, Alloy 5052, known for its excellent weldability, is a preferred choice.
The properties of aluminum alloys are significantly influenced by their heat treatment or temper. Temper O indicates the alloy is in its softened state, offering maximum ductility but minimal strength. Tempers beginning with "T," such as T6, T4, and T3, involve heat treatment processes. These may include aging or cold working to enhance the alloy’s strength at a molecular level.
Once the appropriate alloy and temper are selected, the next steps involve specifying dimensions and additional fabrication processes. Aluminum tubing typically has outer diameters ranging from 0.062 inches to 3.00 inches and wall thicknesses from 0.010 inches to 0.250 inches. Suppliers can shear, flare, bend, and fabricate tubing according to customer specifications. Additionally, aluminum tubing can be recycled at the end of its service life due to its composition of 99.8% pure aluminum alloy.
When selecting aluminum tubing and piping, consider the following factors:
Metal tubing is known for its rigidity, which helps it maintain its shape. While most tubing designed for smooth fluid flow has a round cross-section, there are also options available in various shapes, such as rectangular, oval, square, and circular. Some manufacturers can provide custom shapes, although these tend to be more expensive than standard options. Among these shapes, circular tubing is the most commonly used due to its ability to provide consistent distribution throughout the length of the tube.
Each metal tubing selected should meet the following performance specifications:
Features of the piping should also be evaluated before making a purchase. Here are important features that every metal piping should possess:
Both the inner and outer surfaces of metal tubing require finishing and coating. The tubing must be treated with a particular finish, such as:
This section will explore the different varieties of aluminum tubing and piping.
The 5052 aluminum pipe is a specialized alloy designed for enhanced performance. It is an aluminum-magnesium alloy known for its improved resistance to corrosion. This alloy, while being of moderate strength, incorporates small amounts of iron, silicon, manganese, and copper among other elements.
The seamless 5052 aluminum pipe is manufactured from solid metal, ensuring that the pipe is free from welds and maintains precise dimensions.
The 5052 aluminum box pipe is ideal for applications requiring substantial strength and durability. Known for its long service life, this aluminum alloy maintains its shape and integrity over time. The strength of the piping can vary based on the specific application and the form or shape of the pipe used.
Welded from aluminum sheets, the 5052-0 aluminum welded pipe offers enhanced strength compared to standard piping. However, the 5052-0 ERW pipe can only be cold worked for further strengthening, as heat treatment is not suitable for this alloy.
5052 aluminum alloy hollow pipes are widely used, with various forms including round, square, box, hexagonal, rectangular, and hydraulic types. Among these, the round pipe is the most commonly used, while the 5052-0 aluminum alloy square pipes are often employed in structural applications.
5083 aluminum pipes are among the many aluminum alloys used across different industries. ASTM B241 aluminum seamless pipes are characterized by their smooth, drawn finish and fine granular structure, which facilitates precise and easy anodization. The addition of magnesium and other elements in this alloy significantly enhances its resistance to corrosion, making it particularly suitable for marine environments.
The 5083 aluminum alloy is particularly valued for its resistance to marine environments. It is extensively used in high-strength applications where durability is critical. While aluminum alone is less robust compared to steel, alloying it with elements such as magnesium enhances its strength, although it still falls short of steel’s performance. EN AW-5083 aluminum welded pipes are among the toughest non-heat-treatable aluminum alloys, with cold working used to improve their strength after the drawing process, as they cannot be heat treated.
AA 5083 aluminum ERW (Electric Resistance Welded) pipes are known for their excellent welding properties, which allows them to be easily integrated with other metal piping systems. The 5083 aluminum alloy is versatile, with round pipes from ASTM B210 being especially common. However, there are also various other shapes like square and rectangular tubes, such as those from the EN AW-5083 series.
For specific uses, 5083 marine-grade aluminum pipes are available in different forms, including rectangular shapes. The choice of pipe shape affects its durability and application suitability. Pipes used underwater focus on corrosion resistance rather than strength, whereas above-ground pipes require both strength and resistance to corrosion. The dimensions and wall thickness of these pipes are crucial, with 5083 grade aluminum schedule 40 pipes being a popular choice for marine applications due to their robustness and durability.
The 5086 aluminum pipe is a specialized form of aluminum alloy designed to enhance the material's properties. Aluminum is naturally lightweight and resistant to corrosion but is more reactive with water compared to steel. To address some of these limitations, 5086 H32 aluminum pipes are produced with alloying elements to improve their mechanical performance.
The inclusion of manganese in 5086 aluminum pipes enhances their strength and significantly boosts their resistance to corrosion, particularly in aquatic environments. While pure aluminum may react with water, the alloyed version is more stable, making it suitable for marine and seawater applications.
One of the standout features of aluminum alloys is their light weight, which is particularly advantageous in industries where reducing the weight of components can lead to energy savings and efficiency improvements, such as in transportation.
Aluminum 5086 piping comes in various forms, including the box type, which is often used for structural purposes due to its strength. The 5086-H32 aluminum welded pipes are particularly robust and are commonly employed in the oil, natural gas, and petroleum sectors. The choice of material often depends on specific application requirements and cost considerations.
The 5086-H32 aluminum ERW pipes are weldable and can be integrated with other metal pipelines. Among the 5086 aluminum alloy pipes, the hollow type is widely used, with options available in box, rectangular, square, and round shapes. Of these, the round pipes are the most commonly used.
Following steel, aluminum is extensively utilized, and the 5086-H32 aluminum alloy square pipes represent just one of many variations designed for different industrial applications. Numerous alternatives exist to provide the necessary mechanical properties for specific uses.
The 6061 aluminum pipe represents a specific grade of aluminum tubing. Both pure and alloyed aluminum are used in its production. This type of pipe is made from an alloy combining silicon and manganese. Various schedules define the pressure ratings and wall thicknesses of these pipes. For instance, the 6061 T6 schedule 80 aluminum pipe is considered a moderate pressure grade, capable of withstanding significant pressure in residential applications.
The 6061 aluminum pipe exhibits good resistance to corrosion. The incorporation of manganese and silicon in the alloy enhances its strength. The 6061 Schedule 40 aluminum piping provides moderate strength and resists collapsing during bending, unlike pure aluminum grades.
The 6061-T6 aluminum piping offers a range of strength from moderate to high, making it quite durable compared to other aluminum grades. It is frequently used in structural applications where substantial strength is required. Although aluminum itself is relatively weak, the alloying elements and heat treatment processes improve its strength to meet various application needs.
The 6061 aluminum thin walled pipe is utilized in applications in which the finish must be good-looking. Almost all aluminum alloy piping metals have a good finish and look better. Aluminum piping is also utilized in aesthetic applications. However, aluminum reacts with water. So it isn’t ideal as a plumbing metal under normal conditions.
The 6061-T6 aluminum seamless piping is engineered to enhance strength while preserving many of aluminum's beneficial properties, such as its resistance to corrosion. This type of piping is widely used in aerospace and aircraft industries where reducing weight is crucial. Additionally, the 6061 T651 aluminum welded piping is well-suited for applications that require welding due to its ease of weldability. Similarly, the aluminum alloy 6061 ERW piping is favored for projects that involve welding operations.
6063-T6 aluminum pipes are alloys of aluminum containing silicon and magnesium, designed to enhance both strength and resistance to corrosion. These pipes can undergo heat treatment following extrusion to further improve their durability and toughness. For instance, 6063-T5 aluminum pipes exhibit a notable elongation of 8% and possess good tensile strength. Various classes and schedules are available to define the different mechanical properties of these pipes.
The 6063 schedule 40 aluminum pipes specify the wall thickness, with sizes ranging from 1.25 inches (3.18 cm) to 6 inches (15.24 cm). The 6063 T4 aluminum grade is favored in architectural applications due to its suitability for the field.
6063 aluminum seamless pipes, which are drawn directly from raw metal, offer a high-quality finish. The fine grain structure allows for effective anodizing. Additionally, 6063 welded pipes are robust and can be welded using techniques like tungsten inert gas (TIG) welding. Various forms of 6063, including T6, T5, and T4, find applications across different industries.
6063 aluminum is popular in visible architectural applications for its aesthetic qualities. Among its variants, the 6063-T6 aluminum hollow pipe is extensively used, although other forms are also available.
The round shape is the most common for 6063-T6 pipes, but other forms such as rectangular, hexagonal, and square are also used. This grade is employed in constructing window and door frames, roofs, and signage, providing medium strength for these applications.
For applications requiring greater structural strength, alloys such as 6061 or 6062 are recommended. The 6063-T5 schedule 40 pipes are examples of how wall thickness and diameter specifications are defined.
7075 Aluminum Piping, often referred to as aircraft-grade aluminum, is a high-strength alloy primarily composed of zinc. This alloy is known for its exceptional strength and is widely used across various industries and applications due to its superior mechanical properties.
7075 aluminum seamless pipes are crafted from raw metal, ensuring precise dimensional accuracy, which is crucial for applications in the aerospace industry. The 7075 aluminum box pipes are particularly valued for their strength and are commonly employed in hydraulic systems and lifting operations where durability and performance are essential.
The 7075 aluminum alloy hollow pipe is one of the commonly utilized types. Due to strength needs, the 7075 alloy square tubes are also commonly utilized in the aerospace industry.
Aluminum pipe is a type of metal pipe manufactured from aluminum, widely used across various industries. While it is more cost-effective than copper, it is generally not used in plumbing applications due to its susceptibility to corrosion when exposed to water. Aluminum reacts with water, forming oxides that can contaminate the water supply.
Seamless Aluminum Pipe is produced directly from solid aluminum, avoiding any welded seams or marks. Available in various sizes and shapes, this type of piping is designed to address the inherent weaknesses of aluminum by optimizing its strength and durability.
Aluminum Square Pipes are suitable for applications requiring increased strength and resistance to collapse. Unlike round pipes, which may be weaker at bends, square pipes offer enhanced durability at the corners due to their geometric design.
Aluminum Section Pipes are used in larger-scale applications such as aircraft fuselages and fuel pipelines. The lightweight nature of aluminum makes it ideal for systems where reducing weight is crucial. Aluminum seamless pipes are particularly useful in high-precision, lightweight applications. Connection between pipes can be achieved using threaded joints.
Threaded Aluminum Pipes allow for connections without the need for welding. These pipes come in various diameters, with larger pipes needing additional support from structures like lattice frameworks to ensure stability.
Spiral-Welded Aluminum Pipes are made by spirally cutting and welding aluminum plates, offering a unique manufacturing approach.
Anodized Aluminum Pipes undergo an electrical treatment to form a protective or decorative oxide layer on their surface, enhancing their durability and appearance.
Jindal Black Anodized Aluminum Pipes feature a black anodized finish that provides both a decorative appearance and improved corrosion resistance. Various types of aluminum piping are employed in applications where corrosion resistance and lightweight properties are essential, particularly in water line systems.
This section will explore the various uses and advantages of aluminum tubing and piping.
Aluminum's excellent heat absorption makes it an ideal choice for temperature regulation applications, such as in solar power systems, refrigerators, and air conditioning units.
The lightweight yet durable nature of aluminum tubing makes it valuable in hydraulic systems, structural braces, fuel lines, and frameworks.
Both aluminum pipes and tubes are widely utilized across various industries and construction projects. Additionally, they are increasingly popular among automotive manufacturers and homeowners, reflecting their versatile applications. The previous sections have highlighted many of these uses.
The advantages of using aluminum tubing and piping include:
Aluminum tubing may not offer the best strength-to-weight ratio compared to other materials. Some aluminum alloys also lack the corrosion resistance found in stainless steel, which makes them less suitable for applications like electrical cables.
Welding aluminum tubes requires specific techniques due to the oxide layer that forms on their surface. This oxide can wear out welding tools more quickly, making the process more expensive compared to welding steel.
The first factor to consider when buying aluminum tubing is what industry it is to be used and what qualities are required in this industry. Light weight, durability, strong plasticity, low maintenance cost, high toughness, and corrosion resistance are features of aluminum tubing.
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