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Dissertations / Theses on the topic 'Pressure Welding'
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Van, Zyl Carlo Angelo Antonio. "Analysis and modelling of the temperature distribution during the friction taper stud welding of 10CrMo910." Thesis, Nelson Mandela Metropolitan University, 2008. http://hdl.handle.net/10948/720.
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Heat generation during the FTSW process plays and important role in determining the characteristics of the weld. In order to obtain temperature fields, a transient temperature heat analysis is required. An area is the maximum temperatures reached within the base material during the FTSW process. These temperatures will be measured during experimentation, and compared to the welding simulation done using FEA. From the literature search it appeared that no heat transfer analysis had been done using finite element methods.
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Agers, Bryan Michael. "An investigation into the mechanism of pressure welding." Thesis, Swansea University, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.570649.
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Göktuğ, Gökhan. "On the effect of environmental pressure on gas tungsten arc welding process." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/39620.
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King, Benjamin. "Welding and post weld heat treatment of 2.25%Cr-1%Mo steel." Access electronically, 2005. http://www.library.uow.edu.au/adt-NWU/public/adt-NWU20060404.095844/index.html.
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Prymak, David John. "A New Method of Measuring Flow Stress for Improved Modeling of Friction Stir Welding." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9081.
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Deficiencies in friction stir welding (FSW) numerical modelling are identified. Applicability of flow stress data derived from hot compression, hot torsion, and split Hopkinson bar testing methods is assessed. A new method of measuring flow stresses in the stir zone of a friction stir welding tool is developed. This test utilizes a non-consumable flat-faced cylindrical tool of different geometries that induces a vertical and rotational load on the material of interest. A constant vertical load and rpm value is used for each test yielding the resulting motor torque and temperature generation to define the material response. Experimental samples are cross-sectioned, polished, and etched to reveal the material flow behavior below the tool. A viscosity-based model is used to quantify the shear stress and rim shear rate present in the shear layer below the tool. This test is referred to as the high-pressure shear (HPS) experiment. A parameter window is developed for two alloys of interest, AA6061-T6 and AA2219-T87 and results are reported. The HPS experiments yields flow stress estimates that are pressure and strain rate dependent. Different tool geometries are explored to understand the impact of the "dead zone"at the center axis of the tool. When compared to hot compression and hot torsion the HPS flow stress datasets trend 20-86 % lower across the two materials tested.
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Viehrig, Hans-Werner, Eberhard Altstadt, Mario Houska, Gudrun Mueller, Andreas Ulbricht, Joerg Konheiser, and Matti Valo. "Investigation of decommissioned reactor pressure vessels of the nuclear power plant Greifswald." Helmholtz-Zentrum Dresden - Rossendorf, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:d120-qucosa-235681.
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The investigation of reactor pressure vessel (RPV) material from the decommissioned Greifswald nuclear power plant representing the first generation of Russian-type WWER-440/V-230 reactors offers the opportunity to evaluate the real toughness response. The Greifswald RPVs of 4 units represent different material conditions as follows:
• Irradiated (Unit 4),
• irradiated and recovery annealed (Units 2 and 3), and
• irradiated, recovery annealed and re-irradiated (Unit1).
The recovery annealing of the RPV was performed at a temperature of 475° for about 152 hours and included a region covering ±0.70 m above and below the core beltline welding seam.
Material samples of a diameter of 119 mm called trepans were extracted from the RPV walls. The research program is focused on the characterisation of the RPV steels (base and weld metal) across the thickness of the RPV wall. This report presents test results measured on the trepans from the beltline welding seam No. SN0.1.4. and forged base metal ring No. 0.3.1. of the Units 1 2 and 4 RPVs. The key part of the testing is focussed on the determination of the reference temperature T0 of the Master Curve (MC) approach following the ASTM standard E1921 to determine the facture toughness, and how it degrades under neutron irradiation and is recovered by thermal annealing. Other than that the mentioned test results include Charpy-V and tensile test results. Following results have been determined:
• The mitigation of the neutron embrittlement of the weld and base metal by recovery annealing could be confirmed.
• KJc values of the weld metals generally followed the course of the MC though with a large scatter.
• There was a large variation in the T0 values evaluated across the thickness of the multilayered welding seams.
• The T0 measured on T-S oriented SE(B) specimens from different thickness locations of the welding seams strongly depended on the intrinsic structure along the crack front.
• The reference temperature RT0 determined according to the “Unified Procedure for Lifetime Assessment of Components and Piping in WWER NPPs - VERLIFE” and the fracture toughness lower bound curve based thereon are applicable on the investigated weld metals.
• A strong scatter of the fracture toughness KJc values of the recovery annealed and re-irradiated and the irradiated base metal of Unit 1 and 4, respectively is observed with clearly more than 2% of the values below the MC for 2% fracture probability. The application of the multimodal MC-based approach was more suitable and described the temperature dependence of the KJc values in a satisfactory manner.
• It was demonstrated that T0 evaluated according to the SINTAP MC extension represented the brittle fraction of the data sets and is therefore suitable for the nonhomogeneous base metal.
• The efficiency of the large-scale thermal annealing of the Greifswald WWER 440/V230 Unit 1 and 2 RPVs could be confirmed.
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Bergstedt, Edwin. "A Study in How Welding Parameters Affect the Porosity in Laser Welded High Pressure Die Cast AM50 Magnesium Alloy." Thesis, KTH, Materialvetenskap, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-291119.
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There are a need for reducing the weight of vehicles, one solution is to implement cast lightweight materials such as the high pressure die cast AM50 magnesium alloy. The weldability of this cast alloy is poor and to implement the use of the alloy commercially a welding process is needed that limits the porosity of the weld. The aim of this thesis is to study the effect of the welding parameters on the porosity in the weld, for three laser welding methods. The welding methods examined are single spot and twin spot laser using either a beam splitter or separate optics. The microstructure of the base material are also examined in order to evaluate relations between the components of the microstructure and the porosity in the weld. It was concluded that the hydrogen in the base material was the main reason for the observed porosity in the weld and that the material contains high pressure gas. The welding parameters did not influence the porosity for the single beam laser process, however, for the dual beam processes the welding parameters could affect the amount of pores. It was found that a double weld reduced the amount of pores and that the size and distribution of the secondary phase particles would benefit from the treatment. The cleaning of the samples prior to welding increased the porosity, however, non-cleaned samples contained more oxide inclusions. The results indicate that a twin beam process could reduce the porosity in the weld of the AM50 alloy.Det finns ett behov av att reducera vikten på fordon, en lösning är att implementera gjutna lätta material såsom formsprutad AM50-magnesiumlegering. Svetsbarheten hos denna gjutna legering är dålig och för att kommersiellt kunna använda legeringen krävs en svetsprocess som begränsar svetsens porositet. Syftet med detta examensarbete är att studera svetsparametrarnas effekt på svetsens porositet för tre lasersvetsmetoder. De svetsmetoder som undersöks är enkelpunkts och dubbelpunktslaser där antingen en stråldelare eller separat optik använts. Basmaterialets mikrostruktur undersöks också för att utvärdera sambandet mellan mikrostrukturen och porositeten i svetsen. Man drog slutsatsen att väte i basmaterialet var huvudorsaken till den observerade porositeten i svetsen och att materialet innehåller gas under högt tryck. De undersökta svetsparametrarna påverkade inte porositeten för processen med en laserstråle, men för dubbelstråleprocesserna kan svetsparametrarna påverka mängden porer. Det visade sig att en svets utförd med två strålar minskade mängden porer och att storleken och fördelningen av sekundärfaspartiklarna gynnas av behandlingen. Prover som rengjordes före svetsning hade ökad porositet, men icke-rengjorda prover innehöll mer oxidinneslutningar. Resultaten indikerar att en dubbelstråleprocess kan minska porositeten då AM50-legeringen lasersvetsas.
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Kocák, Tibor. "Predpříprava a svařování tlakových hliníkových potrubí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318704.
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The project is an analysis of technology production of pressure pipes made of aluminum alloys. The basis is a literary study of TIG technology, aluminum heat-tretable and non-heat-treatable materials. The flange-material is EN AW 5083 and the pipe is made of EN AW 6005A. The design of the welding is compromise between the preparation, the cleaning of the welding edges and the weld metal backing strip. Weld was made in real production. Examined impacts are evaluated on the basis of destructive and non-destructive welding test methods. After heating process of weldment material exhibits better mechanical properties. Using the economical and technological evaluation were selected sutiable proces parameters. The result is a suitable weld of the pressure vessel. Further optimization is possible through automation and robotics.
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Yi, Jihaeng. "Optical Sensors for High-Temperature Pressure Measurement and Real-Time Particle Detection." Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/77229.
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In this thesis, we report the development of two types of optical sensors, one for high temperature pressure measurements and the other for real-time particle detection. With a high melting temperature (over 2000°C), low optical loss, and excellent corrosion resistance, sapphire (α-Al₂O₃) is ideal for high temperature sensing applications. Fabry-Perot (FP) cavity with optical interrogation of pressure response. The prototype is based on an extrinsic FP interferometer design and is constructed by combining reactive ion etching (RIE) with direct wafer bonding. Long-term testing proves that the adhesive-free wafer bond is sufficient to create a sealed Fabry-Perot cavity as a pressure transducer. Pressure measurement over a range of 6 to 200 psi has been demonstrated at room temperature using white-light interferometry.
For the other sensor, the goal is to detect the presence of micro- and nanoparticles in real time. The sensor is based on a silica fiber taper, and we aim to detect particle presence by measuring optical scattering and absorption induced by particles attached to the taper surface. To establish the relationship between particle density and optical transmission loss, we first consider a model where Au nanospheres are self-assembled on taper surface through electrostatic interaction. An analytical model is established to describe the adsorption of gold nanospheres onto cylindrical and spherical silica surfaces from quiescent aqueous particle suspensions. The curved surfaces of the fiber taper and microspheres are coated with nm-thick layer of a polycation, enabling irreversible adsorption of the negatively charged spheres. Our results fit well with theory, which predicts that the rates of particle adsorption will depend strongly on the surface geometry. In particular, adsorption is significantly faster on curved than on planar surfaces at times long enough that the particle diffusion length is large compared to the surface curvature. This is of particular importance for plasmonic sensors and other devices where particles are deposited from a suspension onto surfaces which may have non-trivial geometries.
We have established a theoretical model that can describe optical loss generated by particles on taper surface. This theory is validated by measuring, in real time, optical loss during the self-assembly of gold nanoparticles. We find that the measured optical loss can be quantitatively explained by the presence of multiple guided modes within the fiber taper region. Based on this work, we incorporate a fiber taper into a cascade impactor and show that welding aerosols attached to the fiber taper surface can induce measurable transmission loss during the welding process.Ph. D.
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森, 敏彦, Toshihiko MORI, 健治 広田, Kenji HIROTA, 進幸 千田, Shinkoh SENDA, 貴司 足立, and Takashi ADACHI. "PCR加工による異種材質円管の重ね圧接." 日本機械学会, 2000. http://hdl.handle.net/2237/9034.
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Kontšek, Marián. "FMECA analýza svařovacího procesu jednoduché tlakové nádoby." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2018. http://www.nusl.cz/ntk/nusl-378409.
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This diploma thesis is dealing with researching the EU legislative and mapping the welding process of simple pressure vessel, elaborating the FMECA analysis of this process with subsequent proposal of precautional measures in critical points of this process, arising from this analysis.
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Vareskic, Srdjan. "Utmattningsanalys av tryckkärl i enlighet med SS-EN 13445-3." Thesis, Högskolan i Halmstad, Akademin för ekonomi, teknik och naturvetenskap, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:hh:diva-28737.
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Detta examensarbete har utförts i samarbete med Fagerström Industrikonsult AB i Helsingborg. Fagerström Industrikonsult AB är ett ingenjörsföretag som har specialiserat sig på mekaniska och mekatroniska produkter inom flera branchområden. Ett av företagets tidigare projekt, som bland annat bygger på tryckbärande kärl och som kommer återanvändas för ett nytt projekt, är i behov av en uppdaterad analys mot utmattningsbrott.För att en tryckbärande utrustning skall kunna säljas och användas inom Europa, måste tillverkarna följa det Europeiska direktivet 97/23/EG, även kallat PED-direktiv. Detta direktiv sätter regler för konstruktion, tillverkning, märkning och kontroll. I Sverige finns denna beskrivning i Arbetsmiljöverkets författnings-samling (AFS 1999:4 2011). För att uppfylla alla de konstruktionsmässiga och tillverkningsmässiga krav på tryckkärlet som ställs i PED direktivet, så måste harmoniserade standarder användas. I detta arbete används tryckkärlsstandarden (SS-EN 13445-3: 2014) som sätter regler för design och verifiering av tryckbärande anordningar.Ett av projekten som finansierats av den Europeiska kommissionen, visade att 25% av alla tryckbärande anordningars haverier beror på utmattning. Tryckkärl är den typ av tryckbärande anordning, som är mest utsatt för skador orsakade av utmattning. Utmattningsbrott har varit känt sedan början på 1800-talet och man har länge studerat detta fenomen. Man har efter lång tids arbete hittat metodik för att ta fram analytiska modeller och prediktionstekniker samt säkra och noggranna livslängdsberäkningar för stålkonstruktioner. Fagerström Industrikonsult AB söker idag en metod för att utföra utmattningsanalys på tryckkärl i enlighet med tryckkärlsstandarden där linjärstatisk analys utförs med finita elementmetoden. Företaget eftersträvar också mer kunskap inom ämnet för att ge konstruktörerna bättre kännedom om utmattningsproblematiken samt ge möjlighet att redan i konstruktionsstadiet kunna sätta rimliga krav på tillverkning ur mekaniskt utmattningsperspektiv.This master thesis has been carried out in collaboration with Fagerström Industrikonsult AB in Helsingborg. Fagerström Industrikonsult AB is an engineering company, specialized in mechanical and mechatronic products across a wide range of industry segments. One of the company's previous project, which is among other sub-products based on pressurized vessels, and that will be reused for a new project, needs an updated analysis against fatigue failure.In order to sell or use a pressurized equipment in Europe, the manufacturers must comply with the European Directive 97/23/EC, also called PED-directive. This directive sets the rules for design, production, marking and inspections. In Sweden, this directive is described in “Arbetsmiljöverkets Författningssamling” (AFS 1999:4 2011). In order to meet all the design and manufacturing requirements for pressure vessels that are required by the PED Directive, it is required to use harmonized standards. In this thesis, pressure vessel standard (SS-EN 13445-3: 2014) is used, which sets the rules for design and verification of pressure vessel.One of the projects funded by the European Commission, showed that 25 % of all pressure equipment failure are caused by fatigue. Pressure vessel is one type of these pressure equipment, which is most vulnerable to damage caused by fatigue. Fatigue failure has been known since the beginning of 19th century and this phenomenon has been studied for a long time. Under this extensive period of time, methods have been succefully developed for analytical models and prediction techniques as well as safe and accurate life calculations for steel structures. Fagerström Industrikonsult AB is today seeking a method to perform fatigue analysis of pressure vessels in accordance with European pressure vessel standard, where the linear static analysis is performed using the finite element method. The company is also pursuing more knowledge of the subject so its designers have more understanding of fatigue phenomena in order to be able to set reasonable requirements during design stage for production and in order to prevent this phenomena.
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Schmidt, Hein. "The design of a pressure vessel and testing procedures for the determination of the effect of high temperature pressurised helim on valve contact welding / Hein Schmidt." Thesis, North-West University, 2004. http://hdl.handle.net/10394/500.
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The PBMR (Pebble Bed Modular Reactor) is one of the current developments in the field of
nuclear power generators. The control philosophy of the PBMR system relies heavily on the
controlling of valves. The current control valves are subjected to a maximum temperature of
350°C with a pressure difference of 90 bar. Control optimisation can be obtained by including
'hot valves" into the system. The biggest improvement is possible with a bypass-valve after
the low-pressure turbine outlet. This valve will be subjected to a temperature of 720°C with a
pressure difference of 52 bar. PBMR personnel raised the concern that the components of
these valves (valve seat and sealing surfaces) in contact with the hot helium gas could tend to
weld to each other when they are in contact. An investigation was done to establish whether
these surfaces tend to weld together.
As no literature was found on testing for prevention of welding of materials under high
temperature pressurised helium conditions (Chapter 2), a testing facility was designed to test
the hot bypass-valve material (AISI H10) under operating conditions. This included the
design of a pressure vessel according to ASME Vlll Division 1 (Chapter 3) to be able to
simulate the helium operating conditions and a bolted connection (Chapter 4) to simulate the
valve contact conditions.
A finite element analysis was done, using ALGOR FEMPRO software (Chapter 5), to verify
the internal stresses of the pressure vessel based on the maximum allowable stresses for
material UNS NO6230 (Haynes® 230© Alloy), from Appendix 4 of ASME Vlll Division 2.
Firstly, a steady state heat transfer analysis was done to calculate the pressure vessel
temperature distribution. During a static stress analysis, these results were used to assign
the temperature dependent material properties to the various finite element elements. The
helium pressure and external pressure were simulated as uniform surface pressures. Based
on the Tresca effective stress results the maximum allowable 0.2% yield strength of Haynes
230 was exceeded. According to this analysis, the pressure vessel will yield when subjected
to the specified operating conditions. The calculated stresses also exceeded the ASME Vlll
Division 2 - Appendix 4 maximum allowable material stresses.
It is recommended that the same analysis be done with another FEM analysis software
package, to verify the calculated material stresses. This analysis should be incorporated into
the follow-up study, where the water-cooling system must also be designed. Before the
manufacturing of the pressure vessel can commence, a third party inspector must approve
the design. Any design updates necessary from the inspector's report should also be
included in the follow-up study.Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.
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Moselli, Andrea. "Sviluppo e validazione sistema di controllo di processo di saldatura meccanica a freddo applicato alla produzione di accumulatori di energia." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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La saldatura meccanica a freddo (CPW: cold pressure welding) risulta essere un argomento non molto studiato e dotato di una bibliografia piuttosto scarna in merito all’applicazione che questa tesi vuole sviluppare, ovvero la giunzione per sovrapposizione di connettori elettici di accumulatori di energia.
Lo studio qui riportato, prosegue lavori già svolti in precedenza mirati al raggiungimento del medesimo obiettivo.
Tuttavia, partendo da questi dati, il mio elaborato si propone di espandere le conoscenze in
merito a questa tecnologia e sondare la possibilità di poterla applicare realisticamente in ambito industriale dove finora non ha ancora avuto la possibilità di essere sfruttata a dovere, in favore della ben più studiata e applicata saldatura ad ultrasuoni (UMW: ultrasonic metal welding).
In particolare questo lavoro si può suddividere in due fasi ben distinte:
Nella prima parte si è ricercata la correlazione tra i parametri necessari all’applicazione in macchine automatiche, ovvero la resistenza di giunti saldati con tecnologia CPW e la riduzione di spessore degli stessi, con la prospettiva futura di poter correlare direttamente quest’ultima con la pressione che l’ha generata.
Nella seconda, dopo aver riscontrato una forte dipendenza tra i parametri oggetto di studio, si è potuto procedere a porre le basi per l’industrializzazione del processo, andando quindi a studiare la durata dei componenti e l’affidabilità degli stessi all’interno di una macchina progettata ad hoc per questa applicazione.
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Nell, Ryno Willem. "Development of a novel nitriding plant for the pressure vessel of the PBMR core unloading device / Ryno Willem Nell." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4227.
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The Pebble Bed Modular Reactor (PBMR) is one of the most technologically advanced developments in South Africa. In order to build a commercially viable demonstration power plant, all the specifically and uniquely designed equipment must first be qualified. All the prototype equipment is tested at the Helium Test Facility (HTF) at Pelindaba. One of the largest components that are tested is the Core Unloading Device (CUD).
The main function of the CUD is to unload fuel from the bottom of the reactor core to enable circulation of the fuel core. The CUD housing vessel forms part of the reactor pressure boundary. Pebble-directing valves and other moving machinery are installed inside its machined inner surface. It is essential that the interior surfaces of the CUD are case hardened to provide a corrosion- and wear-resistant layer. Cold welding between the moving metal parts and the machined surface must also be prevented. Nitriding is a case hardening process that adds a hardened wear- and corrosion-resistant layer that will also prevent cold welding of the moving parts in the helium atmosphere.
Only a few nitriding furnaces exist that can house a forging as large as the CUD of the PBMR. Commercial nitriding furnaces in South Africa are all too small and have limited flexibility in terms of the nitriding process. The nitriding of a vessel as large as the CUD has not yet been carried out commercially. The aim of this work was to design and develop a custom-made nitriding plant to perform the nitriding of the first PBMR/HTF CUD.
Proper process control is essential to ensure that the required nitrided case has been obtained. A new concept for a gas nitriding plant was developed using the nitrided vessel interior as the nitriding process chamber. Before the commencement of detail design, a laboratory test was performed on a scale model vessel to confirm concept feasibility. The design of the plant included the mechanical design of various components essential to the nitriding process. A special stirring fan with an extended length shaft was designed, taking whirling speed into account. Considerable research was performed on the high temperature use of the various components to ensure the safe operation of the plant at temperatures of up to 600°C. Nitriding requires the use of hazardous gases such as ammonia, oxygen and nitrogen. Hydrogen is produced as a by-product and therefore safety was the most important design parameter. Thermohydraulic analyses, i.e. heat transfer and pressure drop calculations in pipes, were also performed to ensure the successful process design of the nitriding plant.
The nitriding plant was subsequently constructed and operated to verify the correct design. A large amount of experimental and operating data was captured during the actual operation of the plant. This data was analysed and the thermohydraulic analyses were verified. Nitrided specimens were subjected to hardness and layer thickness tests.
The measured temperature of the protruding fan shaft was within the limits predicted by Finite Element Analysis (FEA) models. Graphs of gas flow rates and other operation data confirmed the inverse proportionality between ammonia supply flow rate and measured dissociation rate. The design and operation of the nitriding plant were successful as a nitride layer thickness of 400 μm and hardness of 1 200 Vickers hardness (VHN) was achieved.
This research proves that a large pressure vessel can successfully be nitrided using the vessel interior as a process chamber.Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2010.
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Попов, Станіслав Володимирович. "Модель інструменту для зварювання легень." Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/43672.
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Обсяг дипломної роботи складає 72 сторінки, містить 64 ілюстрації, 17 таблиць. Загалом було опрацьовано 23 літературних джерела.
Актуальність: на сьогоднішній день не існує повноцінного інструменту для зварювання легень, який зміг би гарантовано впоратись з особливо твердими її частинами, такими як бронхи, замість цього використовують загальні інструменти для зварювання м’яких тканин.
Структура легень неоднорідна, окрім паренхіми, бронхів, альвеол, трахеї, кровоносних судин легені, під час зварювання, легені заповнені повітрям, що привносить складнощі в процес зварювання. Це вимагає від інструменту підвищених параметрів надійності та міцності.
Мета: модель та дослідження на статичне навантаження інструменту для зварювання легень.
Завдання:
– огляд літератури по темі зварювання легень;
– оглянути інструменти для зварювання легень та результати проведених операцій по зварюванню легень та інших живих тканин;
– обрати середовище моделювання інструменту для зварювання легень та визначити умови проведення даної процедури;
– створити модель інструменту для зварювання легень та провести дослідження інструменту на статичне навантаження на стиск;
– проаналізувати отримані результати.Scope of the diploma is 72 pages, contains 63 illustrations, 17 tables. 23 sources were totally processed. Relevance: nowadays there is no full-fledged tool for welding the lungs, which could be guaranteed to cope with particularly hard parts of lungs, such as the bronchi, common tools for welding soft tissues are used instead. The structure of the lungs is heterogeneous. Except the parenchyma, bronchi, alveoli, trachea, blood vessels, the lungs are filled with air, which causes difficulties during welding process. Everything mentioned above requires from the tool improved parameters of reliability and durability. Objective: to model and study the static load of a lung welding tool. Task: – review of literature on lung welding; – inspect lung welding tools and the results of operations performed to weld lungs and other living tissues; – select the modeling environment of the lung welding tool and determine the conditions for this procedure; – create a model of a lung welding tool and conduct a study of the tool for static compressive load; – analyze the results obtained.
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Sláma, David. "Návrh nového designu a výroby komponenty nízkotlakého vývodu." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-318789.
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The aim of this work is make a new design and technology of the low-pressure output part of rail which is made in BOSCH DIESEL s.r.o. company. In the thesis is analyzed in detail the bending test, which is part of the quality control of the low-pressure welding joint. In the next part of the thesis is proposed the process of machining of this component, followed by experimental finding of welding parameters for resistance welding. Then several pieces are welded, which are measured and tested. The results of this tests are compared with customer requirements. Finally, a technical and economic evaluation of the change is made, which will save a considerable amount of money for the company.
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Cave, W. R. "Investigation of the constricted plasma arc process for hyperbaric welding at pressures 1 to 100bar." Thesis, Cranfield University, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360220.
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Гараненко, Тетяна Романівна. "Розробка процесу формоутворення порожнистої лопатки з титанових сплавів для газотурбінних двигунів." Doctoral thesis, Київ, 2021. https://ela.kpi.ua/handle/123456789/40560.
Full textAbstract:
Запропоновано конструкцію фрагменту порожнистої металевої лопатки
вентилятора гофрового типу, враховуючи фактор зниження маси пера лопатки за
рахунок конструктивно - технологічних рішень при збереженні експлуатаційних
параметрів (властивостей статичної та динамічної міцності). Проведено порівняльний
статичний та динамічний аналіз експлуатаційних навантажень лопатки вентилятора
суцільної та порожнистої конструкції. На основі виконаного аналізу доведено
доцільність вибраної конструкцію поперечного перерізу фрагменту порожнистої
лопатки.
Запропонована структура технологічного процесу виготовлення порожнистих
лопаток, яка ґрунтується на поєднанні двох процесів - зварювання під тиском і
формоутворення пера лопатки в ізотермічних умовах.
Розроблено метод експериментально - аналітичної побудови кривих
деформування на підставі випробувань на згин. Результати дослідження показали, що
криві в’язкопластичного деформування матеріалів, можна використовувати для
розрахунку технологічних процесів.
За результатами відпрацювання комплексної технології виготовлення фрагменту
порожнистої лопатки розроблено технічні рекомендації щодо реалізації процесів
виготовлення порожнистих лопаток.
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Richardson, I. M. "Properties of the constricted gas tungsten (plasma) welding arc at elevated pressures." Thesis, Cranfield University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280909.
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Nosal, P. E. "Metallurgical investigation of hyperbaric welding at pressures to 250-bar for repairs to deep sea pipelines." Thesis, Cranfield University, 2001. http://dspace.lib.cranfield.ac.uk/handle/1826/11029.
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Friedrich, Sven. "Lineares Vibrationsschweißen von Kunststoffen im industriellen Umfeld." Doctoral thesis, Universitätsbibliothek Chemnitz, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-148986.
Full textAbstract:
Aufgrund der stetig wachsenden Anforderungen hinsichtlich Gewichtsreduzierung und Funktionsintegration, besonders im Bereich des Automobilbaus, werden traditionell aus metallischen Werkstoffen gefertigte Komponenten immer häufiger durch Kunststoffbauteile substituiert. Dem entgegen steht derzeit die Tatsache, dass, trotz hohen Prozessverständnisses und des Wissens um die Prozess-Struktur-Eigenschafts-Beziehungen beim Vibrationsschweißen, die theoretisch erzielbaren Schweißnahtfestigkeiten, von 90 % bis 100 % des unverstärkten Grundmaterials, in der industriellen Serienfertigung bei weitem nicht erreicht werden. Die Komplexität eines industriell gefertigten Bauteils wird an Plattenprüfkörpern simuliert. Die Ergebnisse der Schweißversuche zeigen, dass unterschiedliche Wandstärken im Schweißnahtbereich, Bauteilverzug und unterschiedliche Schwingrichungen innerhalb einer Schweißnaht zu ungleichmäßigen lokalen Prozessbedingungen währenden des linearen Vibrationsschweißprozesses führen. Diese hinterlassen lokale Schwachstellen, welche das Gesamtbauteilversagen bestimmen. Durch alternative Prozessführungsstrategien, wie das Hochdruckanfahren und die IR-Vorwärmung, können diese Schwachstellen reduziert und die Gesamtbauteilfestigkeit angehoben werden. Dies wird am Beispiel des Bauteilverzugs veranschaulichtDue to the increasing demands for weight reduction and integration of function, especially in the field of automotive, components made of metallic materials are increasingly being substituted by components made of thermoplastic materials. In contrast to this there is currently the fact that, despite the high process understanding of the vibration welding and the knowledge of the process-structure-property relationships, the theoretically achievable weld strengths of 90 % to 100 % of the unreinforced base material strength are far to be achieved in industrial series production. The complexity of an industrially manufactured component is simulated by using plate test specimens. The results of the welding experiments show that different wall thicknesses in the weld area, component warpage and different friction angle within the weld leads to nonuniform local process conditions during linear vibration welding process. This results in local weak spots, which reduce the total component strength. These local weak spots can be reduced by using alternative process strategies, such as in-process pressure variation and IR preheating. So not only the local strengths but also the total component strength will be increased. This is shown on the example of component warpage
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Lin, Wen-Chung, and 林文忠. "Optimization of Welding Process Parameters for Pressure Vessel." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/54456664768251465447.
Full textAbstract:
碩士東南科技大學
防災科技研究所
98
Pressure vessel is considered as one of the dangerous equipment by Taiwan's Labor Safety and Health Law. The dangerous equipment will cause explosion to endangering workers and the public safety if manufactured or used inappropriately. Submerged Arc Welding (SAW) is commonly used in pressure vessel manufacturing. The welding quality will affect greatly to the make use safety of pressure vessel. Taguchi method is one of the most useful tools in experimental design. The method that has been widely used in occasions like less numbers of experiments can handle only single performance characteristic problems. The objective of this paper is to search the optimal welding parameters of SAW that is the most commonly used in the manufacture of pressure vessel by the Taguchi method with Grey relational analysis. The welding parameters (Stick-out, Welding current, Welding voltage, Travel speed) are optimized with considerations of the multiple response performance characteristics (the fusion of root, the face width of weld pool, and the undercut of weld pool).First, the Taguchi’s orthogonal array method which adapts to design an efficient experiment is used to plan the SAW process experiment and welding parameters in layout to reduce the experiment times in this study. In the meantime, the Grey relational grade is also used to find the optimal SAW parameters with the multiple response performance characteristics. The result of the experiment discovered that grey relational grade with the multiple performance characteristics increased from 0.6247 to 0.8042.The improvement percentage of the Grey relational grade is 28.7% that also increased the quality and the safety of pressure vessel. In the future, the dangerous equipment ensures the security of use from the manufacture source. Keywords：Optimization, Taguchi method, Gray relational analysis, submerged arc welding, SAW, Multiple performance characteristics, Dangerous equipment, Pressure vessel
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Lin, Yu-Fu, and 林昱甫. "The Study of Laser Welding to Low Pressure Turbine Blades Material." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/90785005166644953498.
Full textAbstract:
碩士國立臺灣大學
材料科學與工程學研究所
89
Replacement of damaged steam turbine blades is quite often and costly in the operation of power plants. With the improved welding techniques, laser repairing of damaged blades appears to be cost effective together with good quality. AISI 403 stainless steel is a special quality grade used particularly for turbine blades. It has excellent corrosion resistance with the ability to develop hardness and mechanical properties similar to 4130 alloy steel. However, 403 S.S. is subject to hydrogen-induced cracking in the same manner as low alloy steels. Consequently, appropriate precautions must be taken in welding procedures to avoid hydrogen pickup during welding and associated cracking problems. Apparently, weld repairing of 403 S.S. by lasers has advantages such as low heat input and less distortion over conventional repairing methods. In this research, a 5KW CO2 laser was employed in the repairing process. The weld repairing procedure and the selection of alloy powders (filler metals) on the repaired quality of 403 S.S. were performed. Mechanical tests such as fatigue crack growth propagation, impact toughness, and tensile tests along with microstructural analyses of repaired welds were included in the evaluation process. The results indicated that the use of 410 S.S. powder with the adjustment of carbon content by mixing of alloy powders to the level of base material seemed to be very promising in the laser repairing process. It is suggested that the application of laser welding technique to restorate damage 403 turbine steam blades is not only feasible but also practical.
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Peng, Jinning. "Study on Distortion Control in Nozzle Welding of Stainless Steel Pressure Vessels." Thesis, 2011. http://hdl.handle.net/10012/6267.
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The welding of austenite stainless steel often results in large amount of welding distortion due to its high thermal expansion coefficient and low thermal conductivity. This has created great difficulty in the dimensional control of the welded stainless steel structure, ending up with high manufacturing cost. Researches on the welding distortion of stainless steels were very limited, especially for large weld structures with complex component shapes. The studies of this thesis were initiated with focus on the stainless steel nozzle-to-shell-can weld structures, a very typical structural configuration for pressure vessels used in petrochemical and nuclear power generation industries.
Both the experimental and the FEA (finite element analysis), i.e. computational simulation, approaches were taken in the studies which addressed the influences of the welding fixture, the welding sequence, and the welding process on the distortion caused by stainless steel nozzle-to-shell welding. The investigations employed single and multi-nozzle weld test models (called mockups in the thesis) or FEA models. Manual GTAW (gas tungsten arc welding) and SMAW (shielded metal arc welding) processes were selected to represent the most common practice for stainless steel nozzle welding. The FEA simulations were conducted with ABAQUS program using sequentially coupled transient analysis method with lumped weld passes to achieve high computing efficiency.
The investigations on the effect of the welding fixture concluded that the contour fixtures introduced in the thesis be effective for reducing the welding distortion for both the single and the multi-nozzle welding. The contour fixtures tend to localize the welding distortion, hence yield less impact on the global distortion of the whole weld structure. The rib-bar fixture, a more common fixture type for multi-nozzle welding, was found resulting in a big jump in the shell plate distortion when the fixture was removed.
The studies on the influence of the welding sequence revealed that a progressive approach was more favorable for distortion control under the given nozzle-to-shell weld structure configurations. The best sequence suggested is to start welding at one nozzle, firstly on shell OD (outside diameter) side then on ID (inside diameter) side, then proceed to next neighboring nozzle. The effect of the welding direction of each weld pass was found affecting only the nozzle angular distortion.
The experimental data showed that the manual GTAW process developed much higher shell plate distortion than the SMAW process. The reason would be that a higher percentage of the welding heat had been consumed on the base metal. The influence of the weld bead size didn???t appear to be significant. In the FEA study on the effect of the size of the lumped weld pass, the increase in weld bead size even resulted in a decrease in weld distortion. From the FEA simulation point of view, using large lumped pass would be a highly efficient choice without compromising too much in the precision of the distortion prediction. The FEA study confirmed that a decrease in cooling time after welding would result in more welding distortion.
The large scale multi-nozzle mockup with rib-bar fixture demonstrated a maximum out-of-plane shell distortion of 16.4mm after the welding of 10 nozzles with GTAW+SMAW process, which suggests that additional measures should be developed to further control the welding distortion.
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Wu, Lie Jen, and 吳立仁. "Study of Thermoplastic Polymeric Materials Pressure- Displacement and Weldability With Ultransonic Welding." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/14606150602555344157.
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Lin, Ci-Kuan, and 林其寬. "A PC-based Control System for High Pressure Micro-cylinder Welding Processes." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/45245133549494527857.
Full textAbstract:
碩士逢甲大學
自動控制工程所
99
The thesis develops PC-based control programs and the human-machine interface programs for the welding station of a high pressure micro-cylinder filling equipment. The main architecture of the control system is divided into three parts. First, the software is developed by using LabWindows/CVI development tools. LabWindows / CVI is an ANSI C integrated development environment that provides graphical user interface development tools and uses Call Back to trigger events to perform user interface functions generated by the call. The second part is data acquisition. This study uses the NI DAQ X Series NI PCIe-6341 acquisition card to achieve control of welding and to read welding data. Finally, We transmit of the welding parameters with the Miyachi ISA-2000CR inverter power supply, the transmission mode is based on RS-485.We can also be transmitted through the RS-485 to achieve the purpose of adjusting the welding parameters in the man-machine interface. The resistance spot welding technology is used to weld the high pressure micro-cylinder. Positive and negative electrodes exposure to pressure and power, the position makes slightly softening and melting between cover and cylinder at the contact point because instantaneous high current and high temperature, this time exerted by the pressure sufficient to weld together. The positive electrode moves in a straight line by the hydraulic cylinder to contact the negative electrode and exerts pressure. The hydraulic cylinder is controlled by the PC through the NI PCIe-6341 DAQ card via a proportional valve. The HMI is designed to meet the needs of users.
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Zondi, Mthobisi. "Analysis of residual stresses and distortions resulting from multi-pass welding of nozzles to cylindrical pressure vessels." Thesis, 2012. http://hdl.handle.net/10413/8470.
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The purpose of the present study is to obtain insight into the formation, behaviour and magnitude of welding-induced residual stresses and distortions resulting from welding nozzles onto cylindrical pressure vessels. A hybrid methodology that comprises numerical analysis, experimental measurements and empirical calculations is used in the present study. The welding process induces a high thermal gradient on the material due to non-uniform temperature distribution; thereby causing the portion of the material that is exposed to high temperatures to expand. However, the relatively cooler material portion that is away from the weld pool resists such expansion, thereby subjecting the structure to stresses and distortions around the fusion zone (FZ) and the heat-affected zone (HAZ).
Over the last two decades a number of studies have been done in an effort to predict the effect of welding-induced residual stresses on the integrity of welded structures. However, to this end, such studies have focussed on analysing residual stresses on bead-on-plate, plate-to-plate and [to a less extent] on pipe-to-pipe weld joints. Fewer studies have looked at nozzle-cylinder joints of pressure vessels as is the case in this study. The second chapter gives a detailed review of applicable literature. The constitutive model described in the third chapter includes a two-phase sequentially-coupled thermo-mechanical analysis, which incorporates metallurgical effects. The non-linear transient problem is solved using an axisymmetric 2D model with ‘element birth’ technique, developed on ABAQUS. The first phase comprises the thermal analysis based on Goldak’s moving heat source model that is used to determine temperature histories. The second phase is a sequel stress/strain analysis wherein the temperature fields are used as input loads.
The results discussed in chapters three and four show that there is a high concentration of residual stresses close to the weld centre-line, and these die down as distance away from centre-line increases. It is also shown that the inside surface is under tensile stresses, while the outer surface is under compressive stress, whose magnitude approaches yield strength of the material. Axial deflections of up to 0.384mm and radial shrinkage of 0.0237mm are observed. Distortion decreases as distance away from weld centre-line increases. Minimum axial shrinkage, which is close to zero, is observed at the restrained end. The analytical results show adequate corroboration and agreement with the experimental measurements. A number of mitigation techniques are suggested in order to alleviate the impact of residual stress and distortions on fatigue performance of welded structures.Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2012.
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Chang, Wen-Hsuan, and 張文瑄. "Modeling and analysis of welding-induced distortion and residual stress in pressure vessel and Its effect on buckling strength." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5vuuwh.
Full textAbstract:
碩士國立臺灣海洋大學
系統工程暨造船學系
107
The welding technique, such as gas metal arc welding (GMAW) and shield metal arc welding (SMAW), are commonly used to connect the components of ship in shipyard. During the welding process, the large input of heat causes the distortion and the generation of residual stress of the weldment. Also, it affects the geometry and strength of the component after welding. In this thesis, we simulate the process of plate welding by commercial finite element software, ABAQUS, and we analyze the post-weld residual stress distribution and distortion. We further study the buckling strength of the cylindrical shell after welding. We first perform the welding analysis of flat plate and compare the numerical results with experimental results to verify our simulation process. Then, we performed the analysis of buckling strength of cylindrical shell from the previous experience. There are two steps in the cylindrical shell welding analysis: First, we use coupled temperature-displacement elements to simulate the heating process. The change of the material properties at different temperature, such as Young’s modulus, yield strength, Poisson’s ratio, etc., are considered. And we study the distortion of cylindrical shell after welding, and find out the distribution pattern of distortion and residual stress near the weld bead. Second, we apply the welding-induced distortion and residual stress on the cylindrical shell to perform the buckling analysis, and discuss the influence of the welding-induced distortion and residual stress on the buckling strength of the cylindrical shell. According to the buckling strength analysis of cylindrical shell by solid-element model and plate element model, we know that the plate-element model tends to overestimate the post-welding buckling strength of cylindrical shell. The results of welding simulation in different temperature show that magnitude of deformation and the distribution range of residual stress of the weldment increase as the welding temperature increase. And the buckling strength of cylindrical shell decreases when the welding temperature is increased. By analyzing the different kinds of simplified model of cylindrical shell, we found that the buckling strength of the cylindrical shell which only considers post-welding deformation is underestimated when the buckling wavenumber is low, and the buckling strength is overestimated when the buckling wavenumber is high.
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Amegadzie, Mark Yao. "Effect of forging pressure on the microstructure of linear friction welded Inconel 738 superalloy." 2012. http://hdl.handle.net/1993/8125.
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Inconel 738, which is a nickel base superalloy used for hot section components of aircraft and industrial turbines is difficult to fabricate and repair by fusion welding due to its susceptibility to heat affected zone (HAZ) intergranular cracking. Crack-free joining of the difficult-to-weld alloy is currently achieved by using linear friction welding (LFW). Nevertheless, oxidation along the joint during LFW is a major problem. Information about the effect of process parameters on the microstructural evolution of linear friction welded nickel base alloys is very limited. In this work, the effect of forging pressure on the microstructure of linear friction welded Inconel 738 was studied. The results as elucidated in this work showed that increased forging pressure caused strain-induced rapid solidification of metastable liquid, which resulted in complete elimination of deleterious liquid phase oxides in bonded material contrasting the generally accepted view that assumes extrusion of solid state oxides during LFW.
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BRŮHA, Stanislav. "Optimalizace svařovacích parametrů pro bezkontaktní svařovací technologie vybraných termoplastů." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-153013.
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This diploma thesis deals with the technology of noncontact hot plate welding and hot gas welding and with the optimizing of welding parameters of the chosen thermoplastics, especially of POM and PPA. The individual chapters in the theoretical part focus on following topics: technology of noncontact hot plate welding, technology of noncontact hot gas welding, description of the test welding machines and tools, main process parameters and evaluation of the advantages and disadvantages of each technology. In the practical part the welding parameters are optimized by the Design of Experiment systematic, the short-term capability machine and the microtome analysis are evaluated. In the end there are the results of the welding parameters optimization and comparison of noncontact welding technologies.