M3 U7 Pipe Bending - ECollege
TRADE OFPipefittingPHASE 2Module 3Pipe ProcessesUNIT: 7Pipe Bending
Produced byIn cooperation with subject matter expert:Finbar Smith SOLAS 2014
Module 3– Unit 7Pipe BendingTable of ContentsUnit Objective . 1Learning Outcome . 21.0Bending Processes for Pipe Fitting . 31.1 Pipe and Tube Bending . 31.2 Types of Bending Processes and Equipment Used . 41.3 Press Bending . 41.4 Rotary Draw Bending . 41.5 Mandrel Bending . 51.6 3 Roll Bending . 51.7 Bending Springs . 61.8 Heat Induction Bending. 61.9 Sand Packing Hot-Slab Bending . 62.0Bending Pipe and Tube . 72.1 Parts of a Circle Relevant to Pipe Bending . 72.2 Formula for Determining the Length of Material to Form a 90 Bend. 83.0Effects on Pipe and Tube from the Bending Process . 103.1 Physical Effects on Pipe and Tube from Bending . 103.2 Mechanical Effects on Pipe and Tube from Bending . 103.3 Annealing and Tempering . 104.0Bending Plastic Pipes. 124.1 Heat Bending Plastic Pipes . 124.2 Safety Considerations for Bending Plastic Pipes . 134.3 Guidelines and Safety Precautions for Bending Plastic Pipes . 135.0Hazards and Safety Precautions Associated with Pipe Bending . 155.1 General Safety Precautions for Pipe and Tube Bending Equipment . 155.2 Safety Precautions for Hydraulic Pipe and Tube Bending Equipment. 16Exercises . 18Additional Resources . 19Pipefitting Phase 2Revision 2.0 September 2014
Module 3– Unit 7Pipe BendingUnit ObjectiveThere are seven Units in Module 3 for Pipe Processes. Unit 1 focuses onPiping Materials, Unit 2; Piping components and fittings, Unit 3; Bill ofMaterials, Unit 4; Pipe Preparation, Unit 5; Pipe Joining, Unit 6; Pipe threadingand testing and Unit 7 Pipe bending.Module 3PipeProcessesUnit 1Unit 2Unit 3Unit 4Unit 5Unit 6Unit 7Pipe MaterialsPipingComponentand FittingsBill ofMaterialsPipePreparationPipe JoiningPipeThreadingand TestingPipe BendingIn this unit you will be introduced to the methods of bending pipe, thedifferent bending equipment used and relevant health and safety behaviourguidelines for the bending processes.Pipefitting Phase 2Revision 2.0 September 20141
Module 3– Unit 7Pipe BendingLearning OutcomeBy the end of this unit each apprentice will be able to: Describe the bending process and what methods are used for thedifferent types of pipe. List the types of bending equipment in common use in the pipefittingtrade and their application. Complete practical bending exercise in copper pipe as per ExerciseNos. 2.3.7a and 2.3.7b. Complete mild steel pipe bending exercise using hydraulic bendingequipment as per Exercise Nos. 2.3.7c and 2.3.7d. Complete exercise using heat bending process as per Exercise Nos.2.3.7e and 2.3.7f.Pipefitting Phase 2Revision 2.0 September 20142
Module 3– Unit 7Pipe Bending1.0 Bending Processes for Pipe FittingKey Learning Points Describe the process of Pipe Bending1.1 Identify the different bending processes used in pipe fitting Brief description of each processPipe and Tube BendingPipe bending machines are typically human powered, pneumatic powered,hydraulic assisted, or electric servo motor. In the pipe bending operation thetube may be supported internally or externally to preserve the cross section ofthe pipe. In operations where there is flexibility in the shape of the pipe, thepipe does not need to be supported, however there will be some deformationin the both the cross section of the overall pipe and the wall thickness indifferent areas of the bend.Tube bending as a process starts with loading a tube into a pipe bender andclamping it into place between two dies, the clamping block and the formingdie. The tube is also loosely held by two other dies, the wiper die and thepressure die. After that has been completed the fitter will start the bender,while the tube is pulled around the forming die creating an elbow, U-bend, 2-Dor 3-D bent tubes. A three dimensional tube is a tube with each opening ondifferent planes. A two dimensional tube is a tube with each opening on thesame plane. The picture below shows a typical manual pipe benders with themain parts named.Manual pipe benders for bending thin wall tubePipefitting Phase 2Revision 2.0 September 20143
Module 3– Unit 71.2Pipe BendingTypes of Bending Processes andEquipment UsedPipe bending techniques are varied and offer different advantages anddisadvantages depending on the function of the bend and the type of materialbeing bent. Some use mechanical force and some use heat treatment, the mostcommon are as follows: Press Bending Rotary Draw Bending Mandrel bending 3 Roll Bending Bending springs Heat induction bending Sand packing/hot-slab bending1.3Press BendingPress bending is the simplest and cheapest method of bending cold pipe andtube. The pipe or tube is restrained at two eternal points and a ram in theshape of the bend advances on the central axis and deforms the pipe.The bent pipe or tube is prone to deformation on both the inside and outsidecurvature. The pipe or tube is often deformed into an oval shape depending onthe wall thickness of the material. This process is used where a consistentcross section of the pipe is not required.This type of bending is suitable for bending electrical conduit and similar lightgauge product.Press or Ram bending1.4Rotary Draw BendingThis is the most commonly used style of bender for bending pipe and tubewhere maintaining a good finish and constant diameter is important.Rotary draw benders (RDB) are precise in that they bend using tooling or "diesets" which have a constant center line radius (CLR). The die set consists oftwo parts: The bend die creates the shape to which the material will be bent.The pressure die does the work of pushing the straight material into the benddie while traveling the length of the bend. Often a positioning index table(IDX) is attached to the bender allowing the operator to reproduce complexbends which can have multiple bends and differing planes.Pipefitting Phase 2Revision 2.0 September 20144
Module 3– Unit 7Pipe BendingRotary draw benders are the most popular machines for use in bending tube,pipe and solids for applications like: handrails, frames, instrument tubing andmuch more. Rotary draw benders create aesthetically pleasing bends when theright tooling is matched to the application.Rotary draw bending1.5Mandrel BendingMandrel benders are similar to the rotary draw bender but use an additionalwiper die on the outside of the tube and a mandrel which is inserted into thetube which remains inside the tube during the bend process. This internalmandrel helps to support the shape of the wall when bending. Typically amandrel bender is needed when bending thin wall tubing to a radius muchtighter than the material can bend without collapsing or distorting.1.6 3 Roll Bending3-roll bending is also used for producing work pieces with large bending radii.The method is similar to the ram bending method, but the working cylinderand the two stationary counter-rollers rotate, thus forming the bend. Normallythere are 2 fixed rollers and one moving roller and the work piece is passedforward and backward through the rollers while gradually moving the workingroller closer to the counter rollers which changes the bend radius in the pipe.This method of bending causes very little deformation in the cross section ofthe pipe and is suited to producing coils of pipe as well as long sweeping bendslike those used in powder transfer systems where large radii bends are required.3 Roll BendingPipefitting Phase 2Revision 2.0 September 20145
Module 3– Unit 71.7Pipe BendingBending SpringsThese are strong but flexible springs inserted into a pipe to support the pipewalls during manual bending. They have diameters only slightly less than theinternal diameter of the pipe to be bent. They are typically only used forbending 15-to-25 mm soft copper pipe (used in household plumbing). Thespring is pushed into the pipe until its center is roughly where the bend is tobe. A length of flexible wire can be attached to the end of the spring tofacilitate its positioning and removal. The pipe is generally held against theflexed knee, and the ends of the pipe are pulled up to create the bend. To makeit easier to retrieve the spring from the pipe, it is a good idea to bend the pipeslightly more than required, and then slacken it off a little. They are lesscumbersome than rotary benders, but are not suitable for bending shortlengths of piping when it is difficult to get the requires leverage on the pipeends. Bending springs for smaller diameter pipes (10 mm copper pipe) slideover the pipe instead of inside.1.8Heat Induction BendingIn the case of heat induction, a coil is placed around the pipe. The coil heats asection of the pipe to a temperature between 430 and 1,200 C. Thetemperature depends on the material. The pipe passes through the coil at agradual rate while a bending force is mechanically applied to the pipe. The pipeis then quenched with either air or water spray. The products thus obtainedare generally of high quality, but cost significantly more to produce.1.9Sand Packing Hot-Slab BendingIn the sand packing process the pipe is filled with fine sand and the ends arecapped. The pipe is then heated in a furnace to 870 C or higher. The pipe isthen placed on a slab with pins set in it. The pipe is then bent around the pinsusing a winch, crane, or some other mechanical force. The sand in the pipeminimizes distortion in the pipe cross section. It is an old process but one thathasn’t really been improved on for its flexibility when it comes to uniqueapplications, and so is still in common use.Pipefitting Phase 2Revision 2.0 September 20146
Module 3– Unit 7Pipe Bending2.0 Bending Pipe and TubeKey Learning Points Identify the parts of a circle relevant to pipe bending 2.1Identify how to calculate the length of pipe required to form a 90ºbend.Parts of a Circle Relevant to Pipe BendingWhen bending a pipe to any radius it should be remembered that you areconstructing part of a circle.The parts of a circle relevant to a pipe bending are: The circumference - the outer rim of the circle. The radius - a straight line from the centre of the circle to thecircumference. The diameter - a straight line going from one side of thecircumference to the other passing through the centre. The diameter istwice the length of the radius Every circle has 360 , as shown below.Parts of a Circle360 in a CircleTherefore, there are four 90 segments in every circle.Four 90 Segments in a CircleA 90 bend involves bending a pipe through ¼ of a circle.Pipefitting Phase 2Revision 2.0 September 20147
Module 3– Unit 72.2Pipe BendingFormula for Determining the Length ofMaterial to Form a 90 BendIn the following examples the following abbreviations will be used:C CircumferenceR RadiusD Diameterπ 3.142Example 1Calculate the total length of pipe to be heated to bend a pipe through 90 to aradius of 75mm.To carry out this calculation we must find the length of the circumference anddivide it by 4:IfR 75mmThenD 150mmC πDC 3.142 X 150mmC 471mmTherefore:Length of pipe to be heated 471 4 117.75Which can be written as 118mm.Example 2Calculate the total length of pipe to be heated to bend a pipe through 180 to aradius of 150mm.To carry out this calculation we must find the length of the circumference anddivide it by 2:IfR 150ThenD 300mmC πDC 3.142 X 300mmC 943mmTherefore:Length of pipe to be heated 943 2 471.5Which can be written as 472mm.Pipefitting Phase 2Revision 2.0 September 20148
Module 3– Unit 7Pipe BendingExample 3Calculate the total length of pipe required to bend a pipe through 90 to aradius of 50mm.To carry out this calculation we must find the length of the circumference anddivide it by 4:IfR 50ThenD 100mmC πDC 3.142 X 100mmC 314.2mmTherefore:Length of pipe required 314 4 78.5Which can be written as 79mm.Pipefitting Phase 2Revision 2.0 September 20149
Module 3– Unit 7Pipe Bending3.0 Effects on Pipe and Tube from theBending ProcessKey Learning Points Identify changes in the physical characteristics of pipe and tubefrom bending3.1 Identify changes in the mechanical characteristics of pipe and tubefrom bending Identify the benefits of heat treatment for pipe and tube bending.Physical Effects on Pipe and Tube fromBendingDepending on the bending method used and the material qualities of the pipeor tube being bent some of the following physical effects can be seen afterbending: Wrinkles on the inner side of the bend Stretching of the wall on the outer side of the bend Thinning of the wall thickness on the outer side of the bend Deformation of the cross section of the pipe or tube causing it toreduce and form an oval shape.3.2Mechanical Effects on Pipe and Tube fromBendingThe mechanical properties of the materials are also altered during the bendingprocess. Cold forming causes yield and tensile strengths to rise by 10% Elongation may decrease by as much as15% Bending of the pipe will also tend to result in distortions of the crosssection. The distortions are greater the tighter the radius of the pipe.3.3Annealing and TemperingAnnealing is the treatment of a metal or alloy to reduce its brittleness andimprove its ductility. Annealing is often referred to as the softening of a metal.If a metal becomes work hardened (by bending) it may require softening beforework is continued, otherwise it might fracture. Annealing is achieved by theapplication of heat.Copper pipes are annealed before spring bending. The pipe is heated to a dullred colour and then allowed to cool or quenched in cold water.Pipefitting Phase 2Revision 2.0 September 201410
Module 3– Unit 7Pipe BendingTempering or hardening, is a process of improving the characteristics of ametal, especially steel. Tempering is carried out by heating the metal to a hightemperature and then cooling it, usually by quenching it in oil or water.Cold chisels, screwdrivers, bending springs and the jaws of stilsons areexamples of tools which are tempered.Pipefitting Phase 2Revision 2.0 September 201411
Module 3– Unit 7Pipe Bending4.0 Bending Plastic PipesKey Learning Points Identify specific hazards pertinent to pipe and tube bending4.1 Identify how these hazards are eliminated or minimised Identify how hazards towards others are minimisedHeat Bending Plastic PipesBending of plastic pipes may be desirable under certain conditions where longradius bends and unusual configurations are required. It is possible to bendvarious sizes and wall thicknesses of rigid PVC-U, PVC-C and ABS pipe usingheat bending techniques for long-radius sweeps for conduit and flowconditions. Irregular angles and U-bends for thermal compensation, andoffsets in congested areas can be successfully achieved.Guidelines for heat bending of plastic pipesSuccessful bending requires that the appropriate amount of heat be applieduniformly to the required length of pipe to be bent. This presents the greatestchallenge for field bending, as the heating method used must provide thenecessary amount of heat over the required length of pipe in a reasonableamount of time. Several common pipe heating methods used in the fieldinvolve the use of hot air ovens, electric box heaters, electric pipe heatingblankets, internal electric coiled heating springs and flameless hot gas torches.Temperatures necessary to heat the pipe are dependent on pipe size and theseverity of the desired bend radius. In general, PVC pipe should be heatedfrom 100 C to 135 C for the minimum amount of time necessary to achieveuniform softening. Care should be taken to avoid exposing the pipe to bendingtemperatures for an excessive length of time, as irreparable distortion anddeformation will occur. Localized overheating must be avoided. Successfulminor bends ( 30 ) can be achieved with minimum distortion in the lowertemperature range (100 C) without internal support.Pipefitting Phase 2Revision 2.0 September 201412
Module 3– Unit 7Pipe BendingSharp bends ( 30 ) require higher temperatures (120 -135 C) as well asinternal support. Filling the pipe with fine grain sand or perlite prior to heatingprovides the internal support necessary to prevent wall distortion/collapsewhile at the same time provides an excellent medium for uniform heatdistribution during the heating process.4.2Safety Considerations for Bending PlasticPipesIt should be noted that most bending procedures will induce stress into thepipe wall which can be retained in the material after the bend radius is formed.The amount of stress induced is dependent on the severity of the bend, thediameter and wall thickness of the pipe bent, and the bending method used.This residual stress will be added to the normal stresses created by internalpressure, installation procedures, and the effects of temperature. Therefore,pipe bending should be limited to applications for use at ambient temperaturesor lower where maximum operating pressures are not utilized. The use of afilling medium during the bending process may also cause slight pitting andother interior surface blemishes depending on the method used.Attempting to form bends in rigid thermoplastic piping at temperatures toolow can induce excessive stress into the pipe, thereby jeopardizing its physicalperformance.4.3Guidelines and Safety Precautions forBending Plastic PipesPlease follow these safety precautions prior to conducting any heat bendingprocedures on plastic pipes. Bending procedures must be conducted in a well ventilated area, usingprotective clothing (safety glasses, gloves, apron etc.) to preventdamage or injury. Do not expose pipe to open flames or excessive temperatures. Bends greater than 30 require internal pipe support to preventdistortion. Common methods used to provide internal support to the pipe duringthe bending process include using a filling medium such as fine sand orperlite (cat litter), or inserting a coiled spring into the pipe, or in somecases providing internal pressure. Compact filling medium prior to bending as much as possible toremove any air pockets prior to heating. The pipe ends should be capped or plugged. Minimum radius at bend should not be less than
Pipe Bending Revision 2.0 September 2014 1.0 Bending Processes for Pipe Fitting 1.1 Pipe and Tube Bending Pipe bending machines are typically human powered, pneumatic powered, hydraulic assisted, or electric servo motor. In the pipe bending operation the tube may be supported internally or externally to preserve the cross section of the pipe.
pipe bending springs no. 2450 pipe bending pliers no. 241-242 manual pipe bender - draw bending operation manual bending tool sets no. 243 manual bending tool sets no. 244 manual bending tool sets no. 278 manual bending tool sets no. 240 universal manual pipe bender no. 276 manual pipe bender - pushing bending operation no. 2454-2456 pipe .
Pipe Bending Systems Useful information How do I find the right bending tool Pipe bending pliers no. 242 Manual pipe bender - Draw bending operation Manual bending tool sets no. 243 Manual bending tool sets no. 244 Manual bending tool sets no. 278 Universal manual pipe bender no. 276 Manual pipe bender - Pushing bending operation no. 2456
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There are several types of tube bending method adapted to manufacturers' purpose. In fact, press bending or rotary draw bending method is commonly used to form bend of pipe or tube. B. 3 Roll bending method Press bending is simplest and cheapest method of bending cold tube and pipe. This method is almost the first bending
PiPe benDing systeMs Pipe bending pliers 2415 PiPe bending Pliers › › › For soft copper pipes EN 1057, all non-ferrous metal pipes as well as thin-walled precision steel pipes and brake lines › Bright nickel-plated, handles PVC coated, [ y 0 Code No. 4,75-10,0 3/16-3/8 260 0.580 1442007 241500 with roller 2423 PiPe bending Pliers
tubing [7]. Freeform-bending processes, like three-roll-push bending, shape the work piece kinematically, thus the bending contour is not dependent on the tool geometry. "Fig. ure . 3 " shows the . application. of Pipe. or . Pipe. Bending. "Fig. ure . 3. Applications of Pipe Bending Machine " 2. Problem Identification. 2.1 Heat-Treatment
Abstract: This paper presents the design and fabrication of combined pipe bending and pipe rolling machine. There is no single machine made to perform both rolling and bending operations. Hence we have selected this project to design and fabricate combined bending and rolling of pipe using single power source.
IEEE TRANSACTIONS ON COMPUTER-AIDED DESIGN OF INTEGRATED CIRCUITS AND SYSTEMS, VOL. 33, NO. 9, SEPTEMBER 2014 1277 Placement for Binary-Weighted Capacitive Array in SAR ADC Using Multiple Weighting Methods Yongfu Li, Student Member, IEEE, Zhe Zhang, Student Member, IEEE, Dingjuan Chua, Student Member, IEEE, and Yong Lian, Fellow, IEEE Abstract—The overall accuracy and linearity of a matching .
