In this paper, the hydraulically expanded tubetotube sheet joints for shellandtube heat exchangers made of three sets of commonly used tube and tunesheet materials i. Pdf investigation of the expansion requirement of tube to. Tubetotubesheet joints asme mechanical code issues. Pdf failure analysis of tubetotubesheet welded joints. The joining technique must lend itself to mass production and to. This coefficient can be values smaller than 1, and it can be said that the joint efficiency is a way of reducing the allowable stress of the material. The strength of a rolled joint is influenced by several design parameters, including the type of tube and tubesheet materials, initial tube projection, and the initial radial clearance between the. The option of using partial or full penetration welds or even seal welds for tube to tubesheet joints is up to you, the designer. Jan 04, 2012 tube to tube sheet joint testing kit jtk6500 for simple, quick and reliable testing of tube to tube sheet bore joints. Each tubetotubesheet weld joint is divided into 4 areas a, b, c and d for the investigation of thelocation of indications see fig. Before the fabrication step is begun, a mockup tube to tubesheet joint should be assembled using the same materials and design that is proposed for the full size heat exchanger. Effects of friction on roller expanded tubetubesheet joint strength. Failure analysis was carried out on a tube to tubesheet welded joint of a shell tube heat exchanger to confirm its failure mechanism.
Apr 25, 2016 what is a tube sheet tubesheet for heat exchanger. The calculation of fixed tubesheet exchangers according to. Expanded, and weldedandexpanded tubetotubesheet joints. The collected evidence suggests that the failure of the tube to tubesheet welded joint was induced by fatigue. Less frequently, tubes are expanded by hydraulic processes to affect a mechanical bond. During the examination, a constant water column was maintained between the probe and the tube inside surface. Abstract in this paper, the hydraulically expanded tubetotube sheet joints for shelland tube heat exchangers made of three sets of commonly used tube and tunesheet materials i. Tm6 basic principles of tube expanding elliott tool. Failure analysis was carried out on a tubetotubesheet welded joint of a shelltube heat exchanger to confirm its failure mechanism. Pdf strength analysis of tube to tube sheet joint in shell and. Majumdar november 19, 2008 work sponsored by the us nuclear regulatory commission. See figures 7 and 8 for examples of a mockup tube totubesheet joint. This paper describes preparing mockup tubesheet specimens for visual examination using a digital microscope to determine that tube joint welds are of the specified size and that expanded joints are satisfactory for the intended purpose.
Failure analysis of tube totubesheet welded joints in a shell tube heat exchanger article pdf available in case studies in engineering failure analysis 7 june 2016 with 1,454 reads. Two models of tube and tubesheet, one using tubes as beams and. Roller expansion of tubes in these overenlarged holes may result in tube thinning and weakening of the joint due to a. The collected evidence suggests that the failure of the tubetotubesheet welded joint was induced by fatigue. Tube to tube sheet joint testing kit jtk6500 youtube. As i understand this note is to prevent the leakage from shell side to tube or tube to shell side. For example, if you decide to roll tubes or explosively bond the tubes to the tubesheet, one can take credit for strength and simply use. The ultrasonic examination of the tubetotubesheet weld joint is carried out from inside surface of the tube. Effects of friction on roller expanded tube tubesheet joint strength. Axial deformation of shell and induced stresses at. Strengthweld tubes to tubesheet process heat transfer. Under the morphology analysis, the fracture surface exhibit obvious fatigue crack propagation traces. Pdf on oct 12, 2012, venkata ramesh mamilla and others published strength analysis of tube to tube sheet joint in shell and tube heat.
Experimental study of hydraulically expanded tubeto. Jul 07, 2019 tube to tubesheet joints of some types of shelland tube heat exchangers, such as fixed tubesheet hyydrotest and closed feedwater heaters in which the channel is welded to the shell, are visible only from the channel side with the shell side under pressure and the channel side at atmospheric pressure. The experiment and numerical analysis of different materials zirconium tubes, titanium tubes and 16mnr tubesheets, 316l tubesheet joints were performed in this paper. Hydraulic expansion is the direct application of high internal pressure within a tube or sleeve in order to form a tight joint between the tube and tube sheet or a tight seal between the sleeve and tube. Abstract in this paper, the hydraulically expanded tubetotube sheet joints for shellandtube heat exchangers made of three sets of commonly used tube and tunesheet materials i. A tube sheet is usually made from a round flat piece of plate,sheet with holes drilled to accept the tubes or pipes in a accurate. Thus, the leaking tubetotubesheet or tubesheettotubesheet joint can be localized to the particular set of tubes whose cavities 48 are fluidly connected to the hole network 56 where the leak is detected. This paper advocates correlating rolling torque or hydraulic expanding pressure with shear load strength instead of percent wall reduction as the criterion of expanding adequacy for thinwalled tubes. For example, if you decide to roll tubes or explosively bond the tubes to the tubesheet, one can take credit for strength and simply use a seal weld to assure leak tightness. Tubetotubesheet joints of some types of shellandtube heat exchangers, such as fixed tubesheet hyydrotest and closed feedwater heaters in which the channel is welded to the shell, are visible only from the channel side with the shell side under pressure. This is achieved by a shell and tubes configuration which employ expanded tubetotubesheet joints. A tubetotubesheet joint for steam condensers having a plurality of holes drilled in condenser tubesheets, a plurality of 8 mil triangular cut serrations in the wall surface of each hole, locating the serrations in a set positioned centrally of the wall surface, inserting a tube end into each hole, and forming a mechanical interference fit between tube wall and hole wall surface. Tube to tube sheet joint testing kit jtk6500 for simple, quick and reliable testing of tube to tube sheet bore joints.
Residual stresses in friction stir welded tubetubesheet joint. Before the fabrication step is begun, a mockup tubetotubesheet joint should be assembled using the same materials and design that is proposed for the full size heat exchanger. The ultrasonic examination of the tube to tubesheet weld joint is carried out from inside surface of the tube. Tubesheet repair national board of boiler and pressure. To assure a proper tube joint, the tube wall must be reduced by a predetermined percentage. A rolled joint is the common term for a tubetotube sheet joint resulting from a mechanical expansion of the tube against the tubesheet. Tube to tubesheet joint, creeprelaxation, analytical model, fe model, hydraulic expansion, residual contact stress 1. To ensure leak tightness, the author suggests using seal or strengthwelding followed by expanding tubetotubesheet joints. Introduction the hydraulic expansion of tubetotubesheet joints is a common practice in the assembly of shell and tube heat exchangers. The various analyses for relating and optimizing interfacial pressure to. Strengthweld tubes to tubesheet posted in process heat transfer.
Mar 01, 2007 this article outlines the expanding processes and criteria for expanded joint production. Before the fabrication step is begun, a mockup tube totubesheet joint should be assembled using the same materials and design that is proposed for the full size heat exchanger. By expanding the tube inside the tubesheet, swaging ensures that the space between the two components is always forced closed. This joint is most often achieved using roller expanders. Tube totubesheet joint, creeprelaxation, analytical model, fe model, hydraulic expansion, residual contact stress 1. Us10357816b1 condenser tubetotubesheet joint improvement. Procedure for tube to tubesheet joint expansion letsfab. Were used two shapes joints with two types of fittings surfaces, one with smooth hole of tube sheet and other in which on boring surface we made a groove. A tube to tubesheet joint for steam condensers having a plurality of holes drilled in condenser tubesheets, a plurality of 8 mil triangular cut serrations in the wall surface of each hole, locating the serrations in a set positioned centrally of the wall surface, inserting a tube end into each hole, and forming a mechanical interference fit between tube wall and hole wall surface.
Pdf heat exchanger tube to tube sheet joints corrosion behavior. The proposed tube end expansion method and welding. See figures 7 and 8 for examples of a mockup tubetotubesheet joint. Reliability study of the hydraulically expanded tubetotubesheet. A tube totubesheet joint for steam condensers having a plurality of holes drilled in condenser tubesheets, a plurality of 8 mil triangular cut serrations in the wall surface of each hole, locating the serrations in a set positioned centrally of the wall surface, inserting a tube end into each hole, and forming a mechanical interference fit between tube wall and hole wall surface. An expansion joint is a speciallydesigned component of compact dimensions that allows differential movement between two adjacent components and maintains the pressure envelope. What is the type of joint between tube and tube sheet in a. Pdf investigation of the expansion requirement of tube. Tube to tubesheet joint details and tube bundle of dhx. The radiation source is placed on one sidke while the. Supplementary specification to api standard 660 shell and. Additional leak detection systems include monitoring the content of a third fluid which normally fills cavities 48 and is in the pure state. The joining technique must lend itself to mass production and to uniformity of quality.
Introduction steam generators and heat exchanger are used to transfer heat from one fluid to the other. Jun 17, 2015 strengthweld tubes to tubesheet posted in process heat transfer. We refer to the residual stress at the interface as interfacial pressure. Hi, i have been going through one of the shell and tube exchange data sheet and at the end one note was mentioned saying strengthweld tubes to tubesheet. Shell and tube heat exchangers construction details. Port inside diameter for kettle type hefor other type tubesheets 1 c 1 0. Pdf stress calculation at tubetotubesheet joint using. Curran repairs and restores condenser tubesheets using epoxy cladding. The joint integrity is affected by several design parameters, including the type of tube and tubesheet materials, level of expansion and the initial radial clearance between the tube and tubesheet.
In order to create a tubetotubesheet joint, stress at the tubehole interface in the residual stress continuum must be greater than zero after relaxation. To ensure leak tightness, the author suggests using seal or strengthwelding followed by expanding tube to tubesheet joints. The connection joint of tubetubesheet is the weakest parts in a heat exchanger. Analytical modeling of tubetotubesheet joints subjected to. The expansion joints specimens were prepared at the pressure ranging from 28mpa to 38mpa. Measure and record the tube hole inside diameter id.
Nov 25, 2016 there are four types of tube to tubesheet joints. An expansion joint in the shell of fixed tubesheet styles can be provided for broad temperature differences between shell and tube side flows. Tubesheet epoxy cladding steam condenser performance is impacted when tube and tubesheet sealing joint is leaking. Experimental study of hydraulically expanded tubetotubesheet. Qexp1 tube expanding procedure specification teps company name. Such limitations apply only to exchangers with removable tube bundles, namely utube and. Tight, durable seating of tubes in tubesheets is one of the critical functions in manufacturing. Joint efficiency can be defined as the reliability that you can obtain from welded joint. Experimental study of hydraulically expanded tube to.
Seperation of condenser tube to tubesheet joints youtube. A variety of methods are used for making the joint between the tubesheet and the tubes. Basic principles of tube expanding tube expanding is the art of reducing a tube wall by compressing the o. The importance of a sound tubetotubesheet joint cannot be overem. Pressure vessel technol november, 2008 related proceedings papers.
Failure analysis of tubetotubesheet welded joints in a. Sometimes a packed joint is used, see mechanical design of heat exchangers, figure 1, for a packed floating head but these are limited to low pressure and low. Roll or expand only without grooves strength is poor leak resistance is poor tube replacement is very easy application is limited i. Modeling the effects of initial tube tubesheet clearance, wall reduction and material strain hardening on rolled joint strength j. See figures 7 and 8 for examples of a mockup tube to tubesheet joint. The residual contact traction and the joint structural strength are examined against the expansion pressure and the initial radial clearance. This paper discuss about evaluation of stresses of tubesheet joint and axial deformation of shell and tubes of heat exchanger for dewaxing application under transient thermal loading. This article outlines the expanding processes and criteria for expandedjoint production.
Therefore, the joint efficiency depends on the level of non. Basically, the tubesheet is in contact more with the tube side fluid than with the shell side fluid. For weldedandexpanded joints, the author further recommends welding and expanding criteria and nondestructive examinations. Modeling the effects of initial tubetubesheet clearance, wall reduction and material strain hardening on rolled joint strength j.
Repeated destubbing and retubing of heat exchangers in petrochemical plants during their useful lifetime may result in overenlarged tubesheet holes with overtolerances that exceed those prescribed by tubular exchanger manufacturing association tema standards 1988. Calculation of hydraulically expanded tubetotubesheet. Tube type plain material carbonsteel 900ansi in tubepattern 30 96 in pitch 1. The result of its investigation is shown in table 2 and fig. Root cause analysis of indications of tubetotubesheet welds. Although pullout testing does not provide a direct measure of leak. The joint integrity is affected by several design parameters, including the type of tube andtubesheet materials, level of expansion and the initial radial clearance between the tube and tubesheet. In order to create a tube to tubesheet joint, stress at the tube hole interface in the residual stress continuum must be greater than zero after relaxation. Baffles are stamped to close tolerances, minimizing the slippage of liquids or vapors between the baffles and shell wall. Supplementary specification to api standard 660 shellandtube heat exchangers page 1 of 63 s614 december 2018 foreword. Experimental investigation and elasticplastic analysis on. Pdf effects of friction on roller expanded tubetubesheet. Two models of tube and tubesheet, one using tubes as beams and other using tubes as springs has been used to calculate stresses at tube and tubesheet junction.
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