About Tube Fabrication and Tubing Including: Mandrel Bending, Tube
Bending,
Tube
Cutting, Pipe
Bending, Pipe Fabrication, Thin Wall Tubing, Tube Fabricating, Tube Flaring, Tube Rolling & Tube
Swaging.
Tube fabrication uses a variety of techniques to shape, bend, enlarge and cut tubes of all sizes and metals into parts, components and consumer products. While tube fabricators are not generally involved in forming raw metal materials into tubes, the tube fabrication services are far from secondary.
Tube cutting,
tube bending, tube flaring and
tube swaging are highly specialized processes which require specific equipment, such as hydraulic tube benders, CNC mandrel benders and swagging machines, as well as skilled engineers, operators and a range of other facility capabilities. Many consumer items as well as automotive, aerospace and industrial parts are fabricated by precision tube fabrication, including consumer items such as steel handrails, bathroom grab bars, bicycle frames, tent frames, point of purchase displays (POP), plant hangers and outdoor patio furniture. Industrial and manufacturing industries use fabricated tubing and mandrel bent tubing extensively in hydraulic pipe applications such as automotive fuel lines, exhaust pipes, hydraulic cylinders, shell and tube heat exchangers and finned tube heat exchangers. Tube fabricators often fabricate pipe fittings such as floor flanges and pipe elbows as well.
Tube fabrication processes require specialized equipment and skill to form metal tubes in a number of ways. Tube cutting may involve notching, punching or drilling; for precision applications, these processes are often done by CNC, as are many tube fabrication processes. Tube flaring and swaging are both typically cold forging processes which expand the diameter of a certain length of tube or pipe; flaring is applied only to the end of a tube, usually to make the end of the tube capable of connecting with another tube for hydraulic applications. Swaging is a more involved process which expands the diameter of an indefinite length of tube, creating sections of thin-walled tubing without compromising the integrity of the material. Precision swaging can be critical for certain applications, particularly in telescoping tube applications when one tube must slide within another tube. The swage, or the diameter by which a tube is expanded, must be precise in order for one tube to slide snugly inside another tube or tube end. Telescoping tubes are common in consumer and business applications such as stands, tripods and adjustable furniture, while automotive manufacturers and specialty body shops use swaging to control vehicle exhaust.
Tube and
pipe bending can be performed manually with or without a hand-held mandrel, but most tube fabrication facilities have semi-automated and automated equipment which is far faster and more precise. CNC tube bending machines, which are often powered hydraulically for extreme torque power, are capable of forming complex tubing shapes such as coils and zig-zags with extreme precision and short processing times, although all these processes may still be performed manually on traditional tube benders with longer process times. Tube bending which is performed without a mandrel forms wrinkles in the inside of the tube's curve, where the inside diameter of the tube has also been made smaller than it is throughout the tube.
Although wrinkled tube bends are acceptable for some low-performance and non-aesthetic applications, high performance mufflers, hydraulic piping and decorative handrails require smooth, unobstructed tube bends. For these types of applications, mandrels are placed inside the tube in the area being bent. Mandrels are typically a rounded-tip steel rod, linked ball bearings or unlinked steel balls; the straight mandrel, called a plug mandrel, is used on normal bends, while ball mandrels with linked or unlinked ball bearings are used to form critical precision bends. Mandrels are an essential part of the tube fabrication process, as precision winkle-free tube bends would not be possible without their use. Pipe elbows, commonly used in flow and hydraulic applications such as plumbing, require both mandrel bending and flaring or swagging.
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Tube Fabrication and Tubing
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Tube Fabrication Types
-
bends tubes and pipes using computer-controlled
machines that ensure the quality and efficiency of a product. Today's
modern CNC technology has made it possible to produce high volume, close
tolerance, tubular metal parts quickly and economically.
-
is a metal fabrication method of forming tubular metal parts within
a die cavity. This high-pressure method forces fluids inside the die
so that the part expands into its final shape.
- is a process that uses computerized machines to bend pipes.
-
is the tube fabrication process that is most common, although it is
not used for thicker metal tubing. It involves rolling a strip of sheet
metal and curing it.
-
employs mandrels and various dies to manage and control metal flow during
the bending process. In this process, a precision mandrel is positioned
inside the tube, while a pressure die, wiper die, bend die and clamp
dies surround the outside of the tube.
- uses computerized machines to bend tubes.
- is a process that uses computerized machines to cut pipes and tubes.
- uses high pressure to shape tubes.
Tube Fabrication Terms
-
Steel that is alloyed with moderate amounts of chromium and other elements,
such as molybdenum. Alloy steel is distinguished from stainless steel
by good hardening characteristics and from tool steel by possessing better
"toughness" after hardening.
- The heating and
cooling of steel to remove stresses, alter physical, mechanical and metallurgical
properties, increase corrosion resistance and thermally treat steel prior
to age hardening.
- The curved section of
bent tubing.
- Tubing that is not
given heat treatment after the initial welding.
- A family of chromium
nickel stainless steels that have good corrosion resistance and good formability,
but can only be hardened by cold working.
- Less commonly known
as the "bend form" or the "radius die," it is the
primary tool on a rotary-draw tube-bending machine. The bend die is the
form against which the tube is clamped and then drawn around to produce
a bend.
- The process
of annealing in a controlled atmosphere so that dark, adherent oxides
do not form on the metal.
- The amount
of pressure that will make tubing fail or burst by exceeding the tensile
strength of the material from which the tubing is made.
- A measure of warp in
tubing material or the deviation from straightness.
- The normal method
of rotary-draw tube-bending, which is done without heating the tubing
material.
- A measure of a tube's
ability to deform without fracturing.
- The amount of permanent
extension of the material before it fractures.
- A term that
refers to the state of the tube after the weld has been processed to produce
uniform strength and dimensions and the tube has been annealed for corrosion
resistance.
- Tests used
to evaluate the quality of finished products, such as crush, flare, bend,
flange, flatten, reverse flatten, reverse bend and expanding.
- The deformation of
round tubing into an elliptical shape or a symmetrical flattening of a
round tube. Ovality is the measure of the difference between the maximum
and minimum outside diameters of a round tube.
- A protective layer
made of oxides, which is on the outside of tubing, that resists corrosion.
- The chemical removal
of oxides on the surface of metals.
- Tubing specified
for the containment of liquids and gasses, as opposed to structural or
mechanical purposes.
- The unbent section
of a bent tube.