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  1. Tube Sizing Overview

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    In any project that requires tubing, having the right tube size is crucial. Tube dimensions need to be very precise because they hold together important structural elements. At the same time, tubes are different from pipes and hoses, so knowing the differences between these products will help you make good buying decisions. 

    Here we’ll explain the differences between tubes and pipes, common tubing applications, and the importance of selecting the right tubing dimensions.

    Tubes vs. Pipes

    The terms “tubes” and “pipes” might be used interchangeably because of how similar they look, but they have different functions. Pipes usually transport fluid, such as municipal water, so it’s important to keep track of flow volume and pressure using the inside diameter. Tubes also convey substances, but their structural applications—such as medical devices—require precise outside diameter measurements.

    Also note that, while both tubes and pipes are hollow cylinders made of rigid, uniform material, hoses are flexible and layered with different materials. What all these products have in common, however, is a wide variety of applications. 

    In this blog, we’ll focus on the most popular applications for tubes.

    Hydraulic Applications

    Some tubing systems can handle hydraulic applications. They transfer chemicals, solvents, and water. The tubes must be matched with hydraulic fittings that can create a strong enough seal to eliminate the risk of leaks and resist rust or chemical degradation.

    Pneumatic Applications

    Tubes can also belong in pneumatic systems, which transfer gases. Like hydraulic systems, the tubes must be matched with precise, noncorrodible fittings. However, these fittings need to have even more reliable seals to prevent gas leaks.

    Structural Applications

    Tubes can also be used for railings, decorative architectural elements, and structural reinforcements. While these assemblies also have fittings to cap the tubes or secure them in place, they don’t need to be sealed to prevent leaks.

    differences between pipes and tube infographic

    Understanding Tubing Dimensions

    When you’re handling tubing orders, it’s essential to understand how to measure and identify tubes of different dimensions. Tubes are measured by outside diameter—that is, how wide across the tube is, including the thickness of the walls. For example, if a tube is classified as one inch, then its outside diameter is exactly one inch. 

    On the other hand, pipes are measured by nominal pipe size, which correlates to the inside diameter. (For pipes larger than 12 inches, the nominal pipe size corresponds to the outside diameter.) For instance, a one-inch pipe can have an outside diameter of 1.25 inches, whereas a 13-inch pipe is truly 13 inches, counting wall thickness. 

    To effectively measure tube sizes, you need to determine four different dimensions:

    1. The outside diameter of the tube (from the outside edge of the tube wall to the outside edge of the opposing side)
    2. The inside diameter of the tube (the diameter of the hollow portion within the tube walls)
    3. The roundness of the tube. Tubes can flatten or slightly deform during storage or installation, so assessing the tube’s roundness is critical.
    4. The wall thickness, also called the tube gauge. Common gauge sizes range from 7 and 22, with each number referring to a specific measurement. The higher the gauge number, the thinner the wall. For example, a 1.5-inch 10 gauge steel tube refers to a tube with an outside diameter of 1.5 inches and wall thickness of 0.134 inch. A 3-inch 18 gauge tube has a wall thickness of 0.049 inch.

    Tubes and More From E Tube & Wire

    Now that you know the distinctions between tubes and pipes, different tubing applications, and how to measure tubes properly, you can make a more informed decision about your next tubing or piping purchase.

    At E Tube & Wire, we produce precision tubing products. Since 1978, we’ve been providing our clients with high-quality parts and excellent customer service. Contact us today to learn more about our capabilities or request a quote for pricing details.

  2. Aluminum Tube Bending Basics

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    Aluminum tube bending is a precision process for forming aluminum tubes without damaging the material or compromising the internal dimensions of the tube. Experienced tube benders can manage complex bending projects without allowing the metal to develop cracks, kinks, or misshapen interior dimensions that may restrict the flow of fluid. As a strong, lightweight, and highly workable metal, aluminum provides a top choice for producing parts that need to undergo precision metal forming techniques.

    Considerations When Bending Aluminum

    Aluminum Tube Bending Basics

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    When you’re determining which tube stock material to use for different manufacturing projects that require tube bending processes, consider the following:


    Different metals and alloys offer varying degrees of formability. Some are hard and brittle, while others are soft and pliable. Aluminum alloys, in particular, offer a good balance between strength and formability—characteristics that are often at odds with each other in other materials. For projects that require bending with tight radii and multiple bends, you may need to prioritize formability over strength and other characteristics. But for projects with mild bends, stronger and less workable alloys will often work just as well.

    Thickness and Bend Radius

    Like many other metals, aluminum alloys will experience work hardening as they undergo fabrication processes. That’s important to keep in mind for projects with extreme bends. Small-radius (sharp) bends put the metal at risk of cracking, especially if the metal is thick and beginning to harden.

    Percentage of Elongation

    A metal with low tensile strength has restrictions on the degree to which it can be bent. The higher a metal’s tensile strength, the more resilient it is under stress and the better it can handle tube bending processes.

    Best Aluminum Alloys for Bending

    Knowing the characteristics of your chosen alloy is just as important as knowing how many bends and what degrees of bend are required for a project. Some of the best aluminum alloys for tube bending include:

    • Series 3003. Series 3003 aluminums have a 25% elongation rate, making them extremely workable and resilient. These metals respond well to cold working and feature excellent strength characteristics.
    • Series 5052. Series 5052 metals provide an ideal material for cold forming processes. While not as bendable as Series 3003 metals, this series offers higher strength and resistance to corrosion.
    • Series 6061. These metals can be heat-treated or cold-formed and offer excellent elongation and tensile strength properties.

    Aluminum Tube Bending Methods

    Metal fabricators may use multiple processes for aluminum tube bending, such as: 

    Rotary Bending

    This tube bending process uses fixed die sets to shape the outside of the metal tubes. Operators employ mandrels in conjunction with the dies to preserve the interior dimension of the tubes. Mandrels get inserted into the length of the tube adjacent to the bend so the tube can’t crimp shut. Rotary bending is a popular choice because it gives fabricators significant freedom while designing the die set. It can also be used on hard or thick metals with minimal risk of failure.

    Compression Bending

    Compression bending is a fast, cost-effective method of tube bending. The tubes are moved around a stationary die to bend it into shape. While this process is fast and doesn’t require much initial investment for tooling, it can be labor-intensive. It also can’t be used to create complex designs or designs that require a mandrel to preserve the interior shape.

    Induction Bending

    In this process, the metal is heated and softened so it can be forced into a bend. This removes the need for high-cost tooling, and works well for production orders of any volume. However, it can only be used with metals compatible with heat forming methods.

    E Tube & Wire Custom Tube Bending Capabilities

    At E Tube & Wire, we offer complete bending, finishing, welding, and assembly services for metal tube projects. We work with a wide variety of metal alloys and can accommodate complex custom orders. For complex projects, tubes must be in T4 or T0 condition, as T6 tubes such as 6061 T6 can’t always be bent. Contact us today to learn more about our capabilities or request a quote to start your next bending project.

  3. Stainless Steel Tube Bending Methods

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    Tube bending is a metal forming process that permanently bends or changes the shape of tubes and pipes. There are multiple different types of tube bending processes, such as cold forming, heated metal bending, free-form bending, and form-bound procedures. Precision tube bending is a slow, carefully managed process that requires specific tools and honed skills to properly bend the tube without damaging it.

    Stainless steel tubing, whether welded or seamless, can be curved and bent into precise shapes; however, seamless tubes respond best to tight radius bends. Here, we will discuss the various considerations when bending stainless steel tubing as well as the different tube bending methods.

    Stainless Steel Tube Bending Methods

    Considerations When Bending Stainless Steel Tubing

    Before bending stainless steel tubing, there are many variables and structural considerations that must be taken into account. These include:

    • Material Thickness. The thickness of the pipe’s walls affects the final product. Thicker walls require more force to bend, while thinner walls may be easier to crack or wrinkle.
    • Welded Tubing. Welded pipes have a seam that can interfere with the consistency of the bend. The weld itself may have also been improperly formed and cause the tube to not be perfectly round.
    • Bend Radius. Tighter bend radii require more careful application of force. Depending on the thickness and inner diameter of the pipe, a 180° bend may be possible, but it may require a wider “U” shape to preserve the interior shape and structural integrity. The radius also determines what types of equipment can be used to handle the job; three-roll benders typically handle pipes with a large bend radius, whereas mandrel tube bending processes perform tight radius operations.
    • Applications. Stainless steel tubing can be used in applications that need to meet high standards of sanitation, including food processing and pharmaceuticals manufacturing. However, the material can’t be contaminated by carbon during the metal forming or transportation process.

    Methods for Bending Stainless Steel Tubing

    One of the most common methods used for bending stainless steel tube and pipe is rotary draw bending. The radius of such bends is often described as, for example, “2D.” A 2D bend is one whose center-line radius is equal to two times the outside diameter of the pipe to be bent. Rotary draw bending involves clamping on the outside diameter of a pipe and drawing it over a bend die whose radius matches the desired bend radius. Rotary draw bending can employ an internal supporting mandrel and a wiper die to prevent wrinkling on the inside wall of a tight bend. Some rotary draw machines can perform both push bending and rotary bending with a single tooling setup.

    Another common method for forming stainless steel tube and pipe is rolling. In this process, rollers move tubing over or around a die, putting enough pressure on the material to force the tube into the shape outlined by the die. This process needs to be handled slowly and smoothly to minimize stress on the metal and reduce the risk of cracks and deformation.

    Another common method for forming stainless steel tubing is compression bending. In this process, a roller compresses the tube against a die. To protect the internal shape of the tubing, operators can insert mandrels into the pipes. These help the tubing hold its shape so it doesn’t collapse or pinch. 

    Other methods include ram bending, which uses a hydraulic ram to push the stainless steel tube against the rollers; and rotary draw bending, which uses a pressure die, a clamp die, and a round bend die to shape the tubing. Rotary draw bending can create accurate, intricate shapes, so it’s a preferred option for creating consumer and commercial goods.

    Partner With E Tube & Wire for Expert Stainless Steel Tube Bending

    Stainless steel tube bending processes can transform straight lengths of pipe into virtually any shape. However, tubing with different characteristics and intended forms or applications needs to be carefully matched with the right processes. 

    At E Tube & Wire, we specialize in high-quality stainless steel tube bending processes. We provide CNC mandrel tube bending services to meet the needs of various industries, including food processing, automotive, refrigeration, and more. For more information, or to get started on your stainless steel tube bending solution, contact us or request a quote today.