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A Comprehensive Guide to Metal Tubing and Pipes Bending
Metal tubes and pipes are commonly used to convey materials like gas and water. Can tubes and pipes be bent? How to bend? This article will provide detailed information.
Types of Tube and Pipe
There are generally two types of tubing: seamless and Seams(welded). Choosing between welded and seamless tubing depends on the product’s application requirements.
Seamless
Seamless tubes are created by extruding and drawing from a billet, resulting in a smooth interior that reduces the chance of particle buildup. Seamless tubing can withstand higher working pressure, has better corrosion resistance, and can be flared without splitting along the seam.”
Seams
Tubes with seams are created from a roll-formed and welded strip to produce tubing with a seam on the outside and a weld bead on the inside. They are used when a smooth interior is not required. Some tubing has a smoothed weld bead, reducing particle buildup and making it a cost-effective alternative to seamless tubing. Welded tubes are more affordable than seamless tubes and are available in long, continuous lengths.
Comparing of Metal Tubing and Piping
Metal pipe and tubing can be bent, but the two have significant differences when considering seamless and seamed needs. Tubes are gauged by the outside diameter (OD) and wall thickness, while a pipe is gauged by its inside diameter (ID). Regarding functionality, tubing is typically used in aesthetic and structural applications, whereas piping is used for transporting liquids, fluids, and gases. Metal tubes are lighter, easily bent into shape without requiring additional fittings, and are instrumental in connecting tubing to pumps, valves, and other parts.
Pipes & Tubes Bending
Although generally straightforward, pipe and tube bending can lead to issues such as collapsing, dimpling, crimping, and wrinkling . Thin walls, improper material choice, bend radius, and misalignment often cause these issues. Understanding the material, bend radius, and various bending processes is crucial to prevent material damage and loss of production time.
When starting a pipe or tube bending project, consider the product’s intended purpose, thermal conductivity, rust resistance,material weight, and the outside and inside diameters. These measurements determine the wall thickness and bend radius capabilities.
The outside radius stretches when a tube or pipe is bent, causing the material to thin. If the wall becomes too thin, the tube or pipe may collapse into an oval shape, affecting its functionality, especially in precision applications. It is important to ensure that the wall thickness is sufficient for the bent radius. Another key consideration is the Center Line Radius (CLR), which is the distance between the center of the curve and the centerline (axis) of the piping or tubing. The desired CLR will influence the choice of tube bending process used.
Types of Tube and Pipes Bending Processes
Tube and Pipes bending is crucial in various industries, including manufacturing, automobile, and aerospace. It involves using different techniques to achieve specific shapes and angles, each with advantages and ideal applications. Different types of tube bending methods are as follows:
Roll Bending
Roll Bending is a bending method that uses a three or four-roll machine, also known as an Angle Roll or Section Roller. The machine pulls the tube or pipe through the rolls while pressing it into an increasing bend. This method is similar to press bending, using a triangular pattern of support rollers and pressing rollers. However, unlike Press Bending, Roll Bending can bend various angles using the same rollers. The tube or pipe moves through the bending sequence by the powered and turning rollers. This method is an easy and precise way to bend various radii without needing specific tooling for the desired bend radius.
Roll bending creates tube radii and forms pipes, bars, and angles. However, it is a slow process that can result in accurate and consistent results, especially with thin-walled tubing.
Rotary Draw Bending
Rotary Draw Bending faces the challenge of maintaining a pipe’s diameter through bends. Compression bending machines may not produce complex bends and can cause irreversible deformities. Rotary draw bending provides greater accuracy with tubing bending parts, allowing pipes to feature sharp bends while meeting high levels of precision and consistency. It is often used when fabricating tubing parts for machines or structural frameworks.
Rotary Draw Bending is precise, repeatable, and fast, making it ideal for high-volume production. However, the machinery is less flexible and requires costly tooling for each tube/pipe diameter and radius formed.
Compression Bending
Compression bending is a technique that involves applying force against a pipe material to achieve deformation, making it one of the easiest forms of pipe bending. It is commonly used to manufacture electrical conduit pipes with simple bend formations. The compression bending process typically consists of five components: bend die, clamp die, pressure die, wiper die, and mandrel. The bend dies, or mold component, apply pressure on pipe specimens to shape them into their desired form. Other tools, such as clamp die and wiper die, support fabrication in place and prevent defects in the material as the process continues. Although mandrels can be seen on compression bending machines, their usage in the mandrel tube bending process will become apparent later.
Simple tooling can adapt to existing machinery for cheap processing. It’s versatile for bending tubing and pipes.
However, the tubing is prone to crushing easily, which affects its durability. The product’s accuracy and repeatability are poor, leading to inconsistencies in its performance. The production process is very slow, which can result in delays and increased costs.
Mandrel Tube Bending
Mandrel tube bending involves inserting a flexible mandrel rod into the tube while it’s being formed. This allows the tube to conform to its contours comfortably as it changes shape. The use of mandrels helps rotary bending machines bend the material consistently without damaging or warping it over time.
Mandrel bending offers accuracy, repeatability, and shape retention. A mandrel is inserted into the tube during bending to support it and prevent deformation. This method is relatively fast but costly due to the need for specialized equipment and setup time.
Common Materials Used for Tube and Pipes Bending
Many materials are suitable for tube and pipe bending. Below are examples:
- Aluminum alloy: The lightweight, corrosion-resistant material is easy to process and bend.
- Steel: Steel has high strength and rigidity and is suitable for producing heavy-duty structural components.
- Copper: These soft, corrosion-resistant materials are suitable for manufacturing electrical accessories and instruments.
Different materials require different tools and methods for bending, such as manual bending, press bending, pliers, and bending machines. When performing bending operations, consider material thickness, length, angle, and the selection of bending methods.
Equipment Used for Tube and Pips Bending
Tube&pipes bending is a specialized production process that requires specific machinery and systems to reshape tubes effectively. We outline the following equipment used in tube bending and explain why selecting the right equipment is crucial for specific programs.
Benders
Three types of tube benders are hand-operated, semi-automatic, and CNC. Hand-operated tube benders are ideal for small-scale tasks and easy bends, making them perfect for workshops or DIY enthusiasts. Semi-automatic tube benders use both manual and hydraulic operation for greater precision and efficiency in tube bending. They are commonly found in mid-sized production settings. CNC tube benders are highly automated devices that can bend tubes to precise specifications, making them ideal for high-volume production lines and precision-oriented software.
Dies and Tooling
Dies and tooling are essential in achieving preferred bend angles and shapes without deforming or imperfections in the tubing. Mandrels are vital tools that preserve the internal diameter of tubes during bending to avoid wrinkles or collapsing of the tube’s inner diameter within this operation. Wiper dies can be used to remove wrinkles on the surface of bent tubes, making them appear modern. Bend dies are available in many sizes and styles to produce diverse bend angles and radii; therefore, finding one for the preferred result results in manufacturing the required bend in a tube.
Hydraulic Structures
Hydraulic tube benders depend upon hydraulic power units to generate the force necessary to bend tubing accurately and consistently. Therefore, this hydraulic device’s ability and control are vital to produce steady bends.
Clamps and Supports
Clamps and supports keep the tube in place during bending operations, preventing slippage or undesirable deformation. Numerous clamp designs, such as adjustable clamps or vice grips, are available for this purpose.
Measuring and Staining Tools
Specific measurements and markings are essential for developing accurate bends. Calipers and protractors allow us to measure and mark tubing at its exact points where bending occurs, giving us more precise angles.
Choosing the proper tube bender dies and tooling, hydraulic structures, clamps and supports, and measuring and staining tools is crucial for effectively meeting task requirements. This option system guarantees precision, repeatability, and speed by selecting the right equipment.
Quality Control Tips for Bending
Quality tube and Pipe bending components are crucial in various fields, and their consistency and quality are essential. The following procedure ensures that the tube-bending components are of the highest quality.
Material Selection and Inspection
It is crucial to check the quality and specifications of any tubing or pipes you want to use. During fabric inspection testing, cracks or irregularities in the material can trigger an alarm. Finished goods’ structural integrity and quality depend on careful material selection and thorough examination.
Precision Bending Equipment
Properly maintained bending equipment, including tube benders powered by computer Numeric Controlled Management (CNC), is key to maintaining precision and accuracy throughout the bending process. CNC tube benders offer enhanced management and automation features to minimize errors while increasing repeatability and productivity. Quality equipment ensures the bending system is regular and the final components meet the desired specifications.
Tooling and Dies
The selection and protection of tooling and dies play a widespread role in excellent manipulation. Right tooling ensures that bends are made precisely, without deformations or surface imperfections. Normal renovation of dies and tooling is vital to avoid wear and tear that may cause versions to bend exceptionally.
Mandrel and Wiper Dies
The usage of mandrel and wiper dies is not unusual in tube bending. Mandrels preserve the internal diameter of the tube, preventing deformations or wrinkles. Wiper dies reduce surface imperfections and improve the aesthetics of the completed element. Employing the right mandrel and wiper die and ensuring the right maintenance is essential for generating bends.
Tube and Pipe Bending Inspection
Tube and pipe bending is an essential process, and specific standards must be followed to ensure the quality of the final product. The most commonly used tube bending standards in practical engineering are ASTM and JIS, which regulate tube bending performance, size, manufacturing process, and other aspects.
1. Appearance inspection: Inspect the elbow’s appearance, including issues such as bending angle, tube wall cracks, and wrinkles. If defects are found, production should be stopped immediately, and repairs should be made.
2. Ultrasonic testing: Ultrasonic testing can detect defects and changes in thickness inside the elbow. It is more important for high-pressure and large-diameter elbows.
3. Radioactive testing: Radioactive testing is mainly used to inspect large-diameter, medium-thick wall elbows and high-strength steel elbows to detect welding quality and defects in tube walls.
When selecting tube materials, factors such as the purpose of the tube, conveying medium, working environment, pressure, temperature, etc., must be considered. Choosing materials produced by reputable manufacturers to ensure engineering quality is also crucial.
Conclusion
Tube bending has undergone significant changes over the years, and there is a lot to learn about the different types of tubes and the bending process. This article covers every aspect of tube bending, including the common materials, applications, and equipment. If you have questions, please contact us for a prompt reply.
