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Dissertations / Theses on the topic 'Electric arc welding'
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1
Javidi, Shirvan Alireza. "Modelling of Electric Arc Welding : arc-electrode coupling." Licentiate thesis, Högskolan Väst, Avd för maskinteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:hv:diva-5826.
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Arc welding still requires deeper process understanding and more accurateprediction of the heat transferred to the base metal. This can be provided by CFD modelling.Most works done to model arc discharge using CFD consider the arc corealone. Arc core simulation requires applying extrapolated experimental data asboundary conditions on the electrodes. This limits the applicability. To become independent of experimental input the electrodes need to be included in the arcmodel. The most critical part is then the interface layer between the electrodesand the arc core. This interface is complex and non-uniform, with specific physicalphenomena.The present work reviews the concepts of plasma and arc discharges that areuseful for this problem. The main sub-regions of the model are described, andtheir dominant physical roles are discussed.The coupled arc-electrode model is developed in different steps. First couplingsolid and fluid regions for a simpler problem without complex couplinginterface. This is applied to a laser welding problem using the CFD softwareOpenFOAM. The second step is the modelling of the interface layer betweencathode and arc, or cathode layer. Different modelling approaches available inthe literature are studied to determine their advantages and drawbacks. One ofthem developed by Cayla is used and further improved so as to satisfy the basicprinciples of charge and energy conservation in the different regions of thecathode layer. A numerical procedure is presented. The model, implementedin MATLAB, is tested for different arc core and cathode conditions. The maincharacteristics calculated with the interface layer model are in good agreementwith the reference literature. The future step will be the implementation of theinterface layer model in OpenFOAM.
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Erabelli, Prasad Rao 1962. "EXPERT SYSTEM FOR DESIGN OF ARC WELDING (ARTIFICIAL INTELLIGENCE)." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/291579.
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Davies, Mark H. "Numerical modelling of weld pool convection in gas metal arc welding /." Title page, contents and abstract only, 1995. http://web4.library.adelaide.edu.au/theses/09PH/09phd2563.pdf.
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Smailes, Allan J. "Thermal modelling of gas metal arc welding using finite element analysis /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09ENS/09enss635.pdf.
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Ho, Yeu-Chuan 1960. "DESIGN OF ARC WELDING PROCESSES: A CAUSAL PERSPECTIVE." Thesis, The University of Arizona, 1987. http://hdl.handle.net/10150/291663.
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The ability to make rational decisions based on the synthesis of various pieces of information and to eventually arrive at an integrated design plays a very important role in everyday engineering practice. In this paper, a conceptual framework for manufacturing design is obtained through a causal perspective. This framework is used in developing a knowledge-based system that gains insight into the process of arc welding from a few detailed analyses and experiments on simplified models and rationally arrives at an integrated design of the actual process using a hybrid axiomatic-algorithmic approach for design synthesis. The design strategy presented here may also be applied to any manufacturing process in general.
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Farson, Dave F. "Control of arc weld thermal cycles." The Ohio State University, 1987. http://rave.ohiolink.edu/etdc/view?acc_num=osu1387446228.
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Francis, John Anthony. "Principles for open-arc weld deposition of high-chromium white iron surface layers /." Title page, contents and abstract only, 1999. http://web4.library.adelaide.edu.au/theses/09PH/09phf81845.pdf.
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Schneider, Wolfgang. "Studies on arcing phenomena at high current discharges." Thesis, University of Essex, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310044.
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Narula, Swati. "Design, modeling and implementation of improved power quality switched mode power supplies for arc welding applications." Thesis, IIT Delhi, 2015. http://eprint.iitd.ac.in:80//handle/2074/8183.
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INVERNIZZI, BRUNO P. "Soldagem circunferencial do aço inoxidável super duplex UNS S32750 pelo processo MIG com controle CMT®." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/28014.
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Submitted by Pedro Silva Filho (pfsilva@ipen.br) on 2017-11-16T17:59:00Z
No. of bitstreams: 0<br>Made available in DSpace on 2017-11-16T17:59:00Z (GMT). No. of bitstreams: 0<br>Neste trabalho foram realizados experimentos de soldagem circunferencial em tubos de aço inoxidável super duplex UNS S32750, com diâmetros de 19,05 mm e 48,20 mm. Foram executadas soldas utilizando-se diversos parâmetros de soldagem num equipamento MIG com controle CMT® Cold Metal Transfer. Os cordões de solda foram avaliados por inspeção visual e dimensional, além dos ensaios de tração e microdureza Vickers, bem como a análise microestrutural em conjunto com análise de precipitação de fases, a qual foi realizada em acordo com a prática A da norma ASTM A923, e ensaio de corrosão conforme a prática A da norma ASTM G48 em conjunto com a norma ASTM A923. Os resultados indicaram que a soldagem do tubo com diâmetro de 19,05 mm apresentou cordão de solda com dimensões inaceitáveis conforme norma, tendo sido esta condição atribuída a utilização de um elevado diâmetro do arame para as condições (parâmetros) usadas de soldagem. A soldagem do tubo com diâmetro de 48,20 mm apresentou falta de penetração nas condições empregadas, quando soldado pelo processo CMT® convencional. No caso da utilização do CMT® combinado com arco pulsado, em condições que geraram maior aporte de calor durante a soldagem, assim obteve-se penetração total da junta e acabamento superficial adequado. Os resultados indicaram que a soldagem utilizando o processo CMT® combinado com arco pulsado, nas condições (parâmetros) empregados geraram bom acabamento superficial, aliado propriedades mecânicas compatíveis, atendendo exigências de normas, bem como uma microestrutura balanceada e alta resistência à corrosão.<br>Dissertação (Mestrado em Tecnologia Nuclear)<br>IPEN/D<br>Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Bukauskas, Gytis. "Suvirinimo įtampos automatinis reguliavimas." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2004. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2004~D_20040622_143533-26252.
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Suvirinimas elektros lanku yra labai paplitęs visose pramonės šakose. Daugeliu atveju iškyla problemų skaičiuojant ir projektuojant įrenginius, kurie virina elektros lanku. Siekiant pašalinti šiuos sunkumus vis labiau nagrinėjami suvirinimo elektros lanku pereinamieji procesai. Virinant šiuo būdu įvykus trumpajam jungimui vyksta pereinamieji procesai, kurių metu gaunamas gamybinis brokas. Todėl norint pagerinti suvirinimo siūlės kokybę, siekiama, kad kuo greičiau atsistatytų visos sistemos darbinės charakteristikos. Didžiausią reikšmę suvirinant turi elektros lanko įtampa. Šiame darbe nagrinėjami suvirinimo lanko maitinimo šaltiniai, įtampos reguliavimo būdai ir suvirinimo lygintuvai. Tiriamojoje dalyje sudaryta funkcinė schema ir automatinio reguliavimo sistemos struktūrinė schema. Naudojantis programinės įrangos Matlab paketu apskaičiuoti pareinamieji procesai.<br>Electric arc welding is very popular in all branch of industry. There is a lot of problem to calculate and design equipments with boiling electric arc. On purpose eliminate this problems look into transition process for electric arc welder. Bolding in this way processing short conection we have transition process and get manufacturing spoilage. On purpose to have better welding seam we have to have more faster running system characteristic. The most biggest importance of bolding have voltage of welding seam. In this project we will research welding seam feeding sourse, voltage controlling way and bolding leveler. In the inquiring part we will build functional scheme and system flowchart of automatic control. Using Matlab program we will produse transitive process.
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Du, Plessis John. "Control of diffusible weld metal hydrogen through arc chemistry modifications." Diss., Pretoria : [s.n.], 2006. http://upetd.up.ac.za/thesis/available/etd-05152007-131110.
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Miller, Jay. "The development of a curriculum for a course in manipulative skills for shielded metal arc welding." CSUSB ScholarWorks, 1997. https://scholarworks.lib.csusb.edu/etd-project/1188.
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Rousová, Michaela. "Zvýšení efektivity při svařování pecních konstrukcí." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-229241.
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This diploma thesis is resolving all the possibilities of enhancing the efficiency of furnace structures welding. Small batch production does not offer many possibilities for implementing mechanization or automation. On the other hand, when using a big batch production, efficiency can be enhanced by means of a robotic workstation. When the production batch is big enough, we will see a costs save after a short time, mainly in labor costs. This means the return of investments will be in short time period. In the LAC company there are three types of products made. At laboratory furnaces the efficiency can be enhance by using fixtures. At other standard and atypical furnaces is very difficult to design fixtures or positioners because of their different sizes. Big complication can be also a company location on second floor. The most suitable product regarding to welding efficiency enhancement is big batch production of heaters. For this type the welding time can be shortened by means of a robotic workstation.
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Короточ, А. С., Станіслав Вікторович Марченко, Станислав Викторович Марченко та Stanislav Viktorovych Marchenko. "Використання комбінованих електродугових процесів для отримання металу з високими експлуатаційними характеристиками". Thesis, Сумський державний університет, 2018. http://essuir.sumdu.edu.ua/handle/123456789/67476.
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В роботі досліджувалась можливість створення ефективних умов для утворення карбіду титану і його переходу до металу при оптимальному співвідношенні вхідних порошкових компонентів, з використанням СВС (саморозповсюджуваний високотемпературний синетз) технологій при комбінованому електродуговому наплавленні.
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Балькан, Петро Богданович, Віталій В’ячеславович Ковальчук, Petro Balkan та Vitalii Kovalchuk. "Розробка та дослідження системи автоматизованого регулювання напруги зварювальної дуги". Master's thesis, Тернопіль, ТНТУ, 2020. http://elartu.tntu.edu.ua/handle/lib/33210.
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Роботу виконано на кафедрі ком’пютерно-інтегрованих технологій Тернопільського національного технічного університету імені Івана Пулюя Міністерства освіти і науки України Захист відбудеться 21 грудня 2020 р. о 08 .00 годині на засіданні екзаменаційної комісії № 24 у Тернопільському національному технічному університеті імені Івана Пулюя за адресою: 46001, м. Тернопіль, вул.Руська, 56, навчальний корпус №1, ауд. 403<br>У роботі було розроблено автоматизовану систему регулювання напруги зварювальної дуги для забезпечення оптимального параметру процесу зварювання та високих якісних характеристик зварного шва. Було проаналізовано основні параметри, які впливають на процес зварювання, розглянуто схеми регулювання напруги дуги та стабільності процесу зварювання.
An automated arc voltage control system was developed to ensure the optimal parameter of the welding process and high quality characteristics of the weld. The main parameters influencing the welding process were analyzed, the schemes of arc voltage regulation and stability of the welding process were considered.<br>ЗМІСТ
ВСТУП 6
1. АНАЛІТИЧНА ЧАСТИНА 8
1.1. Характеристика процесу дугового зварювання в захисних газах 8
1.2. Особливості зварювання в захисних газах 10
2 ТЕХНОЛОГІЧНА ЧАСТИНА 16
2.1. Методи регулювання напруги дуги при зварюванні 16
2.2. Регулювання напруги дуги за допомогою дроселя насичення 23
2.3. Регулювання напруги дуги за допомогою рототролу 25
2.4. Схеми з регулюючим трансформатором 27
2.5. Головка з автоматично регульованою швидкістю подачі. 29
2.6. Головка з постійною швидкістю подачі. 32
3 КОНСТРУКТОРСЬКА ЧАСТИНА 36
3.1 Фомалізація поставленої задачі. 36
3.2. Аналіз стійкості розробленої системи автоматичного керування. 39
3.3. Критерій Гурвіца. 41
3.4. Критерій Михайлова. 42
3.5. Критерій Найквіста. 43
3.6. Синтез коригувального пристрою. 44
3.6.1. Побудова бажаної ЛАЧХ системи. 44
3.7. Побудова коригуючого пристрою для системи управління. 48
3.8. Вибір електричного аналога і розрахунок його номіналів. 48
4 НАУКОВО-ДОСЛІДНА ЧАСТИНА 51
5. СПЕЦІАЛЬНА ЧАСТИНА 56
5.1. Побудова графіків перехідного процесу в скоригованій системі 56
5.2. Побудова області стійкості адаптованої системи 57
6 ОХОРОНА ПРАЦІ ТА БЕЗПЕКА В НАДЗВИЧАЙНИХ СИТУАЦІЯХ 60
6.1 Технічні рішення з гігієни праці та виробничої санітарії 60
6.1.1 Мікроклімат та склад повітря робочої зони. 60
6.1.2 Виробниче освітлення 62
6.2 Безпека в надзвичайних ситуаціях 64
6.3 Розробка заходів по підвищенню безпеки роботи радіовимірювальних перетворювачів магнітного поля в умовах надзвичайних ситуацій. 65
ОСНОВНІ ВИСНОВКИ КВАЛІФІКАЦІЙНОЇ РОБОТИ МАГІСТРА 67
БІБЛІОГРАФІЯ 68
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Jones, Lawrence Anthony. "Dynamic electrode forces in gas metal arc welding." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11287.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.<br>Includes bibliographical references (p. 306-313).<br>by Lawrence Anthony Jones.<br>Ph.D.
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Kelm, Jonathon. "Modeling and Control Strategies for Multiprocess Arc Welding Power Sources." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1574659504446931.
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Liu, Xiaopei. "Dual Bypass Gas Metal Arc Welding Process and Control." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_diss/664.
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GMAW (Gas Metal Arc Welding) is one of the most important arc welding processes being adopted in modern manufacturing industry due to its advantages in productivity, energy efficiency and automation. By monitoring and improving some of the important properties of GMAW such as production rate, metal transfer and base metal heat input, researchers could bring the process efficiency and stability to a new level. In recent years, some innovative modifications of GMAW such as Twins, Tandem and laser-MIG hybrid welding have been adopted into many industrial applications for better productivity.
In this dissertation, a novel GMAW called DB-GMAW (Dual Bypass Gas Metal Arc Welding) using two GTAW torches and one GMAW torch to construct a welding system, is proposed and developed. In DB-GMAW, two GTAW torches perform the bypass system which decouples the total welding current into base metal current and bypass current after the melt down of filler wire. Compared to conventional GMAW, DB-GMAW has many advantages in droplet formation, base metal heat input and penetration achievement due to its unique characteristics in welding arc and current flow. In the first place of the research, experimental system of DB-GMAW is constructed. Then, sufficient experiments under different parameters are performed to provide us a good understanding of the behaviors and characteristics of this novel GMAW process. Observation about metal transfer formation and base metal heat input is studied to verify its theoretical analysis. Full penetration of work piece via DB-GMAW is achieved based on a series of parameter testing experiments. Moreover, image processing techniques are applied to DB-GMAW to monitor the welding process and construct a feedback system for control.
Considering the importance of maintaining stable full penetration during many welding applications, a nonlinear model of DB-GMAW full penetration is developed in this dissertation. To do that, we use machine vision techniques to monitor the welding profile of the work piece. A control algorithm based on the nonlinear model using adaptive control technique is also designed. The achievement of this dissertation provides a fundamental knowledge of a novel welding process: DB-GMAW, and a good guidance for further studies about DBGMAW.
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Tan, Benjamin H. "A Novel Arc Welding Power Supply with Improved Power Factor Correction." DigitalCommons@CalPoly, 2020. https://digitalcommons.calpoly.edu/theses/2199.
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This paper presents the design and development of a novel Arc Welding Power Supply utilizing a modified two-switch forward converter topology. The proposed design improves the power quality by improving power factor to near unity and reducing total harmonic distortion. State space analysis of the proposed circuit showed that the circuit followed a boost-buck input output relationship. Simulation of the circuit was first implemented in LTspice to verify the functionality of the new topology. Hardware implementation of the proposed design was built on a scaled-down prototype for a proof-of-concept of the new topology. The prototype specifications were created for a 5A, 20V output with a 20-24V, 60Hz input. This project demonstrated that the proposed new topology was successful in obtaining a near unity power factor and a total harmonic distortion of less than 2%. Additionally, the prototype followed the simulation and calculations of a boost-buck function while varying duty cycle, and the final measurements aligned well with waveforms from the simulation.
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Pollock, Helen Geraldine Phyllis. "A series-parallel load-resonant converter for a controlled-current arc-welding power supply." Thesis, University of Warwick, 1996. http://wrap.warwick.ac.uk/4191/.
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A power supply incorporating a series-parallel load-resonant converter, capable of very efficient operation over a wide range of output power is presented. The series-parallel load-resonant converter is shown to have three pairs of resonant frequencies. Operation of the circuit at each of these resonant frequencies maintains zero current switching and high frequency operation. Design mathematics is developed which allow series-parallel load-resonant converters to be designed with specific resonant frequencies and circuit resistances. A new method of power control for series-parallel load-resonant converters is presented; the power delivered to the circuit and hence the load is shown to var substantially depending on which resonant frequency the circuit is excited at. Two series-parallel load-resonant converters are designed simulated, constructed and tested. There is good agreement between the simulation and experimental results. One of the circuits produces an output current of 200 A while the second demonstrates the new power control technique pulsing between 55 A and 145 A while running at frequencies of 63 kHz and 100 kHz. The new power supply is particularly suited to arc-welding. It contains an active rectifier and draws near unity power factor.
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Lu, Yi. "MODEL ANALYSIS AND PREDICTIVE CONTROL OF DOUBLE ELECTRODE SUBMERGED ARC WELDING PROCESS FOR FILLET JOINTS WITH ROOT OPENING." UKnowledge, 2014. http://uknowledge.uky.edu/ece_etds/44.
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Submerged Arc Welding (SAW) for fillet joints is one of the major applications in the shipbuilding industry. Due to the requirement for the weld size, a sufficient amount of metal must be deposited. In conventional SAW process, the heat input is proportional to the amount of metal melted and is thus determined by the required weld size. To meet this requirement, an excessive amount of heat is applied causing large distortions on the welded structures whose follow-up straightening is highly costly. In order to reduce the needed heat input, Double-Electrode (DE) technology has been practiced creating the Double-Electrode SAW (DE-SAW) method for fillet joints. The reduction in the heat input, however, also reduces the penetration capability of the process, and the ability to produce required weld beads has to be compromised. To eliminate the unwanted side effect after using DE-SAW, a root opening between the panel and the tee has been proposed in this dissertation to form a modified fillet joint design. Experimental results verified that the use of root opening improves the ability of DE-SAW to produce the required weld beads at reduced heat input and penetration capability. Unfortunately, the use of root opening decreases the stability of the process significantly. To control the heat input at a minimally necessary level that guarantees the weld size and meanwhile the process stability, a feedback is needed to control the currents at their desired levels. To this end, the fillet DE-SAW process is modeled and a multivariable predictive control algorithm is developed based on the process model. Major parameters including the root opening size, travel speed and heat input level have been selected/optimized/minimized to produce required fillet weld beads with a minimized heat input based on qualitative and quantitative analyses. At the end of this dissertation, a series of experiments validated the feasibility and repeatability of the predictive control based DE-SAW process for fillet joints with root opening.
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Uslu, Mutlu. "Analysis, Design, And Implementation Of A 5 Kw Zero Voltage Switching Phase-shifted Full-bridge Dc/dc Converter Based Power Supply For Arc Welding Machines." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607873/index.pdf.
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Modern arc welding machines utilize controllable high frequency DC/DC power supply with high dynamic and steady state current regulation performance. In the design robustness, small size and low weight, low complexity, and high efficiency are the defining criteria. The most suitable approach for a 5 kW arc welding machine power supply application is the high frequency Full-Bridge Phase-Shifted Zero Voltage Switching (FB-PS-ZVS) DC/DC converter with an isolation transformer. This converter not only gives the advantage of zero voltage switching for a wide load current range, it also provides reduced Electromagnetic Interference (EMI) and reduced component stress compared to standard PWM converters. In this thesis a FB-PS-ZVS DC/DC converter with 5 kW power rating is designed for modern arc welding machine applications. IGBTs are utilized at 50 kHz switching frequency for high efficiency and control bandwidth. The output current of the DC/DC converter is controlled via a Digital Signal Processor (DSP) control platform. The performance of the designed DC/DC converter is evaluated via the computer simulations and the experimental study of the constructed prototype.
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Li, Chao. "WELD PENETRATION IDENTIFICATION BASED ON CONVOLUTIONAL NEURAL NETWORK." UKnowledge, 2019. https://uknowledge.uky.edu/ece_etds/133.
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Weld joint penetration determination is the key factor in welding process control area. Not only has it directly affected the weld joint mechanical properties, like fatigue for example. It also requires much of human intelligence, which either complex modeling or rich of welding experience. Therefore, weld penetration status identification has become the obstacle for intelligent welding system. In this dissertation, an innovative method has been proposed to detect the weld joint penetration status using machine-learning algorithms.
A GTAW welding system is firstly built. Project a dot-structured laser pattern onto the weld pool surface during welding process, the reflected laser pattern is captured which contains all the information about the penetration status. An experienced welder is able to determine weld penetration status just based on the reflected laser pattern. However, it is difficult to characterize the images to extract key information that used to determine penetration status. To overcome the challenges in finding right features and accurately processing images to extract key features using conventional machine vision algorithms, we propose using convolutional neural network (CNN) to automatically extract key features and determine penetration status.
Data-label pairs are needed to train a CNN. Therefore, an image acquiring system is designed to collect reflected laser pattern and the image of work-piece backside. Data augmentation is performed to enlarge the training data size, which resulting in 270,000 training data, 45,000 validation data and 45,000 test data. A six-layer convolutional neural network (CNN) has been designed and trained using a revised mini-batch gradient descent optimizer. Final test accuracy is 90.7% and using a voting mechanism based on three consequent images further improve the prediction accuracy.
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FERRARI, MARCELLO. "Soldagem de chapas grossas em aço baixa liga temperado e revenido ASTM A514 com aço carbono ASTM A36 pelo processo arame tubular." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/27505.
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Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2017-05-25T13:57:54Z
No. of bitstreams: 0<br>Made available in DSpace on 2017-05-25T13:57:54Z (GMT). No. of bitstreams: 0<br>Neste trabalho foram determinadas as condições para a soldagem de chapas grossas de aço carbono ASTM A36 com aço baixo-liga temperado e revenido ASTM A514 Grau Q empregando-se o processo arame tubular. Para tanto foram soldadas diversas peças de testes com o intuito de se avaliar as condições mais adequadas de preparação e soldagem de juntas dissimilares destes materiais. A preparação foi realizada por meio de corte térmico. A temperatura de preaquecimento foi determinada através de modelos matemáticos, pelas recomendações das normas AWS D1.1 e DIN EN 1011-2 sendo posteriormente avaliada por intermédio do teste de soldabilidade tipo CTS Controlled Thermal Severity. Os parâmetros de soldagem foram determinados a partir da qualificação de um procedimento de soldagem, conforme a norma AWS D1.1. Foram avaliadas as consequências do emprego do tratamento térmico de alívio de tensões após soldagem (TTAT), pelos testes de dureza Vickers e impacto Charpy. A caracterização microestrutural foi realizada por meio de microscopia óptica e microscopia eletrônica de varredura. A caracterização das superfícies oxicortadas evidenciou os efeitos da descarbonetação e também da carbonetação. A temperatura de pré-aquecimento de 160°C determinada por meio da metodologia recomendada pelas normas AWS D1.1 e DIN EN 1011-2 mostrou-se satisfatória nos testes de soldabilidade. Foi possível a qualificação do procedimento de soldagem (EPS) com requisitos de impacto na condição \"como soldado\", porém na condição \"após TTAT\", os baixos valores de tenacidade obtidos no metal de solda, inferiores a 27J, não permitiram a qualificação de uma EPS com requisitos de impacto. Foi observada a ausência de trincas intergranulares tanto na zona afetada pelo calor quanto no metal de base ASTM A514, porém foi revelada a presença de microfases frágeis no metal de solda na condição \"como soldado\", especificamente na região da raiz, intensificadas pelo efeito da diluição. O aumento do teor de carbono na raiz, a presença de microfases frágeis, a grande fração de grãos colunares e de ferrita proeutetóide combinados com a baixa fração de ferrita acicular no metal de solda contribuíram para os baixos valores de tenacidade encontrados na condição \"como soldado\". Após o TTAT observou-se uma queda acentuada da tenacidade, inferior a 27J, do metal de solda devido à fragilização provocada pela precipitação e coalescimento de carbonetos de ferro.<br>Dissertação (Mestrado em Tecnologia Nuclear)<br>IPEN/D<br>Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Kottman, Michael Andrew. "Additive Manufacturing of Maraging 250 Steels for the Rejuvenation and Repurposing of Die Casting Tooling." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1416854466.
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Seraphim, Rafael Molena. "Dessorção de gases de juntas soldadas em camaras de ultra-alto vacuo de aneis de armazanamento de eletrons." [s.n.], 2007. http://repositorio.unicamp.br/jspui/handle/REPOSIP/263371.
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Orientadores: Antonio J. Ramirez, Maria Clara F. Ierardi<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica<br>Made available in DSpace on 2018-08-09T21:56:05Z (GMT). No. of bitstreams: 1
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Previous issue date: 2007<br>Resumo: O avanço cientifico no estudo de átomos, moléculas e proteínas tem recebido uma contribuição significativa dos aceleradores de partículas, que em sua grande maioria são utilizados para a geração de radiação síncrotron. Por isso, o aprimoramento destas máquinas mostra-se de extrema importância para manter a ciência em seu contínuo avanço. O sistema de vácuo destas máquinas apresenta-se como um importante parâmetro para o seu bom funcionamento e melhorias neste promovem diretamente melhorias na qualidade da radiação síncrotron gerada. Logo, o desenvolvimento deste trabalho teve como principal objetivo o estudo das juntas soldadas das câmaras de vácuo que compõem o acelerador do Laboratório Nacional de Luz Síncrotron (LNLS). As juntas foram preparadas com o processo de soldagem GTAW (Gás Tungsten Arc Welding) mediante a utilização de diferentes gases de proteção, como Argônio, Hélio e Nitrogênio, e misturas entre estes. Os estudos concentraram-se na análise da influência dos gases de proteção na dessorção de gases das juntas soldadas. Para a caracterização destas utilizaram-se as técnicas de análise de superfícies Dessorção Estimulada por Elétrons (DEE) e Dessorção Estimulada por Fótons (DEF). Adicionalmente, realizou-se um estudo comparativo entre as duas técnicas buscando-se estabelecer relações entre os resultados fornecidos pelas mesmas. Os resultados mostraram que a dessorção de gases independe do gás de proteção de soldagem, mas depende sim do nível de oxidação das juntas soldadas, as quais podem apresentar altas taxas de dessorção caso estejam muito oxidadas e os óxidos não sejam camadas contínuas. Em conclusão pode-se dizer que as juntas soldadas para câmaras de vácuo de aceleradores de partículas devem apresentar baixos níveis de oxidação, e apesar das semelhanças encontradas entre a DEE e a DEF é aconselhável utilizar a DEF para a caracterização de superfícies para trabalharem com radiação síncrotron<br>Abstract: The scientific advance of atoms, molecules and proteins studies has received an important contribution from particle accelerators, which are mainly used to generate synchrotron radiation. Hence, the improvement of these machines is necessary to maintain the continuous advance of science. One of the key components for the adequate operation of these accelerators is the vacuum system. Thus, its improvement directly impacts on the quality of the generated synchrotron radiation. Therefore, the principal purpose of this work is to study the gas desorption from the welding joints on the particle accelerators vacuum chambers. The welds were prepared using the GTAW (Gas Tungsten Arc Welding) process with different shielding gases, as argon, helium and nitrogen, and some mixtures of them. The study concentrated on the analysis of the shielding gas influence on the gas desorption from the welded joints. The gas desorption of the joints was evaluated using Electron Stimulated Desorption (ESD) and Photon Stimulated Desorption (PSD). In addition, it was carried out a comparative study between both desorption techniques to establish relationships between the results provided by them. The results showed that the gas desorption from the welding joints does not depend on the welding shielding gas, but on the oxidation level of the joint, which can present high desorption yield if it is highly oxidized and these oxides are not a continuous film. Therefore, it is advisable to minimize the oxidation during welding of vacuum chambers for particle accelerators. Regarding the comparison between ESD and PSD they were found some similarities. However, PSD will have better performance characterizing surfaces that will be exposed to synchrotron radiation<br>Mestrado<br>Materiais e Processos de Fabricação<br>Mestre em Engenharia Mecânica
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Antonysamy, Alphons Anandaraj. "Microstructure, texture and mechanical property evolution during additive manufacturing of Ti6Al4V alloy for aerospace applications." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/microstructure-texture-and-mechanical-property-evolution-during-additive-manufacturing-of-ti6al4v-alloy-for-aerospace-applications(03c4d403-822a-4bfd-a0f8-ef49eb65e7a0).html.
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Additive Manufacturing (AM) is an innovative manufacturing process which offers near-net shape fabrication of complex components, directly from CAD models, without dies or substantial machining, resulting in a reduction in lead-time, waste, and cost. For example, the buy-to-fly ratio for a titanium component machined from forged billet is typically 10-20:1 compared to 5-7:1 when manufactured by AM. However, the production rates for most AM processes are relatively slow and AM is consequently largely of interest to the aerospace, automotive and biomedical industries. In addition, the solidification conditions in AM with the Ti alloy commonly lead to undesirable coarse columnar primary β grain structures in components. The present research is focused on developing a fundamental understanding of the influence of the processing conditions on microstructure and texture evolution and their resulting effect on the mechanical properties during additive manufacturing with a Ti6Al4V alloy, using three different techniques, namely; 1) Selective laser melting (SLM) process, 2) Electron beam selective melting (EBSM) process and, 3) Wire arc additive manufacturing (WAAM) process. The most important finding in this work was that all the AM processes produced columnar β-grain structures which grow by epitaxial re-growth up through each melted layer. By thermal modelling using TS4D (Thermal Simulation in 4 Dimensions), it has been shown that the melt pool size increased and the cooling rate decreased from SLM to EBSM and to the WAAM process. The prior β grain size also increased with melt pool size from a finer size in the SLM to a moderate size in EBSM and to huge grains in WAAM that can be seen by eye. However, despite the large difference in power density between the processes, they all had similar G/R (thermal gradient/growth rate) ratios, which were predicted to lie in the columnar growth region in the solidification diagram. The EBSM process showed a pronounced local heterogeneity in the microstructure in local transition areas, when there was a change in geometry; for e.g. change in wall thickness, thin to thick capping section, cross-over’s, V-transitions, etc. By reconstruction of the high temperature β microstructure, it has been shown that all the AM platforms showed primary columnar β grains with a <001>β.
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Gideon, Abdullah Mohammed Abdul Fatah, and barrygideon@hotmail com. "Structural Characterisation, Residual Stress Determination and Degree of Sensitisation of Duplex Stainless Steel Welds." RMIT University. Civil, Environmental and Chemical Engineering, 2009. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20091110.101453.
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Welding of duplex stainless steel pipeline material for the oil and gas industry is now common practice. To date, research has been conducted primarily on the parent material and heat affected zones in terms of its susceptibility to various forms of corrosion. However, there has been little research conducted on the degree of sensitisation of the various successive weld layers, namely the root, fill and cap layers. The focus of this research study was to: (i) provide an in-depth microstructural analysis of the various weld passes, (ii) study the mechanical properties of the weld regions; (iii) determine degree of sensitisation of the various weld passes; and (iv) investigate the residual stress levels within the various regions/ phases of the welds. Four test conditions were prepared using manual Gas Tungsten Arc Welding with 'V' and 'U' bevel configuration. Structural analysis consisted of (i) optical microscopy, scanning electron microscopy and magnetic force microscopy; (ii) ferrite determination using Magna-Gauge, Fischer Ferrite-scope and Point Count method. Mechanical testing consisted of Vickers hardness measurements, Charpy impact studies and transverse tensile testing. The degree of sensitisation was determined by three test methods: a modified ASTM A262, ASTM A923 and a modified Double Loop Electrochemical Potentiodynamic Reactivation (DL-EPR) test. Residual stress levels were determined using two neutron diffraction techniques: a reactor source and a time of flight spallation source. Microstructure observed by optical microscopy and magnetic force microscopy shows the formation of both fine and coarse structures within the weld metal. There was no evidence of secondary austenite, being present in any of the weld metal conditions examined. In addition, no detrimental intermetallic phases or carbides were present. The DL-EPR test results revealed that the fill layer regions for all four conditions and the base material showed the highest values for Ir/Ia and Qr/Qa. All four test conditions passed the ASTM A262 and A923 qualitative type tests, even under restricted and modified conditions. Residual stress measurements by neutron diffraction conducted at Lucas Heights Hi-Flux Reactor revealed that the ferrite phase stress was tensile in the heat affected zones and weld, and appeared to be balanced by a local compressive austenite phase stresses in the normal and transverse directions. Residual stress measurements by neutron diffraction conducted at Los Alamos Nuclear Science Centre revealed that in the hoop direction, ferrite (211) and austenite (311) exhibit tensile strains in the weld. In the axial and radial direction, the strains for both phases were more compressive. Correlations between the degree of sensitization and microstructural changes / ferrite content were observed. Higher degrees of sensitization (Ir/Ia and Qr/Qa) were associated with reduced ferrite (increased austenite) content. Correlations between the stresses generated, the evolved microstructures and degree of sensitization were evident. Stresses within the cap region were generally shown to be of a tensile nature in the transverse and longitudinal direction. In summary, the study has shown that correlations exist between the weld microstructure, susceptibility to sensitisation and levels / distribution of internal stresses within the weld regions.
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Case, Robert Jeffrey. "Aspects to commercialize arc welders into new international markets." Thesis, 2011. http://hdl.handle.net/10210/4045.
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Francis, John A. "Principles for open-arc weld deposition of high-chromium white iron surface layers / John Anthony Francis." 1999. http://hdl.handle.net/2440/19484.
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Bibliography: leaves 191-198.<br>xxi, 201 leaves : ill. ; 30 cm.<br>Title page, contents and abstract only. The complete thesis in print form is available from the University Library.<br>Examines the mechanisms controlling the dilution, geometry and wear performance of weld- deposited high-chromium white iron surface layers. Focuses on layers deposited by mechanised flux-cored-arc welding, as this process achieves higher deposition rates than manual-metal-arc welding and affords a greater degree of control over individual welding variables.<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1999
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Davies, Mark H. (Mark Howard). "Numerical modelling of weld pool convection in gas metal arc welding / Marc H. Davis." Thesis, 1995. http://hdl.handle.net/2440/18589.
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Bibliography: leaves 260-302.<br>viii, 302 leaves : ill. (some col.) ; 30 cm.<br>An investigation into the development of numerical models of the Gas Metal Arc Welding (GMAW) process. Models that solve the full equations of motion within the pool are very computationally expensive and their accuracy is limited by the available turbulence and free surface models. An approximate heat-conduction only model has therefore been developed which uses enhanced thermal conductivity to simulate convection within the pool. This model requires several orders of magnitude less computational resources than full cnvection solutions and much less empirical tuning than the modified conduction solutions. As such it appears to be a valuable method for accurate practical prediction of new weld thermal behaviour.<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1996?
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Davies, Mark H. (Mark Howard). "Numerical modelling of weld pool convection in gas metal arc welding / Marc H. Davis." 1995. http://hdl.handle.net/2440/18589.
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Bibliography: leaves 260-302.<br>viii, 302 leaves : ill. (some col.) ; 30 cm.<br>Title page, contents and abstract only. The complete thesis in print form is available from the University Library.<br>An investigation into the development of numerical models of the Gas Metal Arc Welding (GMAW) process. Models that solve the full equations of motion within the pool are very computationally expensive and their accuracy is limited by the available turbulence and free surface models. An approximate heat-conduction only model has therefore been developed which uses enhanced thermal conductivity to simulate convection within the pool. This model requires several orders of magnitude less computational resources than full cnvection solutions and much less empirical tuning than the modified conduction solutions. As such it appears to be a valuable method for accurate practical prediction of new weld thermal behaviour.<br>Thesis (Ph.D.)--University of Adelaide, Dept. of Mechanical Engineering, 1996?
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Dinham, Mitchell. "Autonomous weld joint detection and localisation using computer vision in robotic arc welding." Thesis, 2013. http://handle.uws.edu.au:8081/1959.7/544970.
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At present, robotic welding is a rigid process which requires the robot to be taught by a human operator using teach and playback methods. A significant challenge for robotic welding to be widely adopted is the time taken to program the robot path for new parts. For example, in low to medium volume manufacturing and repair work, robotic welding is not always a viable option, as it can often be quicker and cheaper to weld the parts manually. Some flexibility has been achieved in industry through offline programming software and vision systems that can be used to recognise a pre-taught part and shift the program to accommodate for any positional offsets. However these systems still require a human operator to program the robot path. To achieve true flexibility and make robotic welding a viable option across the wider manufacturing industry, systems should be able to automatically identify the weld joints and then locate its position in the robot’s workspace. Computer vision can be used to achieve this kind of autonomy. However the welding environment presents unique challenges for computer vision. These challenges include poor contrast, reflections from metallic surfaces, and imperfections on the work piece such as rust, mill scale and scratches which are not consistent from part to part. The system should also be adaptable to a variety of surface finishes and base material such as paint, steel and aluminium. This thesis develops an autonomous robotic arc welding system that is capable of detecting realistic weld joints and calculating their position in the robot workspace with minimal human interaction. This is accomplished using a pair of calibrated robot mounted stereo cameras combined with image processing algorithms. An automated calibration method for the robot and stereo vision system and image processing algorithms are developed in this thesis. To obtain accurate positional information from the vision system, an automatic camera calibration method is integrated with simultaneous calibration of the welding robot and robot mounted stereo vision system. This provides accurate geometrical transformations between the robot, cameras and the robot workspace which form the foundation of the computer vision algorithms for both the weld joint detection and localisation. The calibration algorithm is designed for economical and practical implementation. The automatic calibration not only allows for a faster initial calibration, but also reduces the machine down-time for any subsequent calibrations after an accidental collision or if the camera fixture is relocated. Unlike existing methods which require expensive 3D co-ordinate measuring devices or laser scanners, the optimised calibration method developed in this thesis is capable of achieving the sub-millimetre accuracy required for robotic arc welding using only the robot mounted stereo cameras, a mechanical pointer and a calibration board. This makes the proposed calibration method very practical, economical and easy to implement, hence making it highly desirable for industrial applications. This thesis introduces new methods for autonomous identification for both butt and fillet weld joints regardless of the base material, surface finish and surface imperfections. The detection methods analyse the image from a global perspective and are able to identify the weld joint without prior knowledge of the shape of location of the weld joint in the image. The method to detect both butt and fillet joints introduces an approach for the detection of weld joints in realistic work pieces using a novel adaptive line growing technique developed in this thesis. Image matching and triangulation of the weld joint is introduced using 2D homography for planar butt welds and an epipolar geometry based method for fillet welds. In the welding environment, traditional image matching is not reliable, as the images of weld joints typically contain similar shades of grey and are featureless and textureless. New image matching methods for weld joint matching are developed to provide reliable and accurate matching which is invariant to the environmental conditions of the welding environment. The proposed algorithms are validated through experiments using an industrial welding robot in a realistic workshop environment. The results show that the methods introduced in this thesis can provide robust and accurate identification and localisation of weld joints which can be implemented in industry.
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Zhen, Ye. "Seam tracking control of robotic pulsed mag welding by extraction of visual and arc features." Thesis, 2013. http://handle.uws.edu.au:8081/1959.7/565601.
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Currently, most of the robots used in arc welding applications are of the “teach and playback” type, that is they do the welding production by repeating predefined actions. So in order to meet the high quality requirement of the welding process, the demonstrated trajectory of the robot should be close to the weld seam as much as possible. However, this condition is difficult to realize because the seam position is often disturbed by machining error, misalignment error, welding distortion and so on. In this paper, the seam tracking technology for Pulsed MAG welding is studied. The vision sensor is used to collect the welding image, which can get the 2D seam-tracking information. Meanwhile, the arc sensor is used to get the information of the welding torch height, which is also important for the welding quality and difficult to acquire through the vision sensor. The composite sensors technology based on these two sensors can be used in the weld of 3D seam, which provides a possible solution for real-time tracking of 3D weld seam during robotic Pulsed MAG welding process. With the development of welding robots, the increase of the labor cost and the shortage of skilled welders, the seam tracking technology studied in this paper supply important theoretical significance and practical value for promoting the application of the welding robots. To realize the seam tracking function, this paper rebuilt the traditional “teach-playback” robot. On the base of analyzing the characteristics of Pulsed MAG welding and its arc spectrum, a set of visal system was designed to obtain clear welding images. Hall arc sensors were applied to detect the arc information during the welding process, and the program based on DSP was developed to collect and process the signals. The control software based on multithreading program was developed to realize the functions of collecting visual and arc information, information processing and the control of DSP and the robot. For the CCD camera system with one-reflex-ray-path, the relationship mapping was established between the image coordinates and the robotic coordinates. Then the required conditions were analyzed when such relationship mapping was effective, and the original transform formula was modified according the Cartesian coordinates and the joint coordinates. The modified transform formula could be used directly when the robot pose changed. Then in this paper, image features of the Pulsed MAG welding were researched. An adaptive window segmentation method was designed to acquire the arc and weld seam region from the background. An algorithm to extract the wire projection using threshold segmentation was developed by analyzing the gray scale distribution of the arc region. Since the single criterion was difficult to recognize the seam edge from the noise accurately, multi-criterion was proposed in this paper, and some prior knowledge was also introduced to assist the location of the seam edge. The designed algorithm can detect the weld seam edge fast, accurately and stably. After that, possible arc features relating to the welding torch height were proposed according to the characteristics of the pulse power supply and experiments. By analyzing arc information, a filter method based on characteristics of the noise signal was designed to reduce the interference of the noise and improve the accuracy and stability of the arc feature representing the welding torch height. The feature selection algorithm was applied to find the best arc feature and ideal processing parameters. Then the relational model between the arc feature and the torch height was established. To control the trajectory of the robot by the computer, this paper studied the algorithms of line interpolation and circle interpolation in robot working space, based on which a position adjustment method was designed to adjust the robot path in real time. A composite control strategy using adaptive fuzzy PID and fuzzy algorithms was designed to correct robot path. For the lag error introduced by image processing, this paper developed an error compensation algorithm based on modification of the wire projection on the workpiece, which can improve the accuracy and stability of the tracking process. Finally, on the base of above research, a robotic arc welding system with 3D seam tracking function was established and some seam tracking control experiments were conducted. According to the experiments, the system can track different type of seams and get good weld formation. The tracking accuracy can meet the practical requirements of the welding production.
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Суда, Олександр Петрович, та Olexandr Suda. "Вдосконалення технологічного процесу виготовлення трійника для водопровідних труб". Bachelor's thesis, 2021. http://elartu.tntu.edu.ua/handle/lib/35710.
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У кваліфікаційній роботі розроблено технологію виготовлення трійника для водопровідних труб, обґрунтовано обладнання для зварювання патрубків трійника та розраховано параметри та режими ручного дугового зварювання.
У роботі наведено обгрунтування вибору способу виготовлення трійника для водопровідних труб шляхом застосовування удосконаленого способу ручного електродугового зварювання складових деталей трійника, або патрубків круглого діаметру. Прийняті в кваліфікаційній роботі інженерні рішення дозволили підвищити якість зварної конструкції шляхом застосування ручного дугового зварювання методом спирання кутового зварного шва.<br>In the qualification work the technology of making a tee for water pipes is developed, the equipment for welding of tee branch pipes is substantiated and parameters and modes of manual arc welding are calculated.
The paper substantiates the choice of the method of manufacturing a tee for water pipes by applying an improved method of manual electric arc welding of the components of the tee, or round diameter pipes. The engineering decisions accepted in qualification work allowed to increase quality of a welded design by application of manual arc welding by a method of support of an angular weld.<br>Вступ
1. Загально-технічна частина
1.1. Основні етапи розвитку процесу зварювання
1.2. Опис конструкції зварного виробу та технічні вимоги до нього
1.3. Висновки та постановка задач для виробництва трійника для водопровідних труб
2. Технологічна частина
2.1. Характеристика процесу та матеріалу для зварювання патрубків трійника для водопровідних труб
2.2. Опис підготовчих операцій для виготовлення трійника для водопровідних труб
2.3. Характеристика типу та організаційної форми поста зварювання
3. Конструкторська частина
3.1. Вибір пристосування для проведення зварювання трійника для водопровідних труб
3.2. Розрахунок параметрів зварювання патрубків трійника для водопровідних труб
3.3. Розрахунок технологічних показників зварювання деталей трійника для водопровідних труб
3.4. Вибір методів і схеми контролю параметрів зварного виробу
4. Безпека життєдіяльності та охорони праці
4.1. Основні положення безпеки життєдіяльності та охорони праці
4.2. Заходи безпеки від дії електричного струму
4.3. Охорона праці при виконанні зварювальних робіт
Загальні висновки
Список використаних джерел
Додатки
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Yang, Hui-Pin, and 楊譓斌. "A Series Resonant Converter with Variable Frequency and Phase- Shift Control Applied to Electronic Arc Welding Mechines." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/64623821383127967948.
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碩士<br>國立中正大學<br>電機工程學系<br>84<br>This thesis presents the analysis and design for a series-
resonant converter with variable frequency and phase-shift
control applied to electric arc welding machines. With the
proposed control scheme, the main switches of this converter
always hold zero-voltage switching (ZVS) from very light to full
load. The conventional output filter inductor is removed from
the load so as the assumption of a constant current sink is no
longer valid, thus complicating the analyses dramatically. The
operating principles of the converter applied to a welding
machine are described in detail from which the boundary
condition between continuous conduction mode (CCM) and
discontinuous conduction mode (DCM) are therefore derived, and
the design procedure is outlined as well. Computer simulated and
experimental results obtained from a prototype are presented to
confirm the analytical derivation.
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CHAO, CHIH-LUNG, and 趙芝龍. "Ti-15V-3Cr-3Sn-3Al Alloy in Electron Beam and Tungsten Inert Gas Arc Welding Produce Microtexture and Mechanical Property Analysis." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/86168697449053485408.
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碩士<br>國防大學中正理工學院<br>兵器系統工程研究所<br>94<br>Considering that the Ti-6A1-4V alloy widely used by the industrial field is insufficient for molding work, a series of mechanical properties and microstructure analysis was conducted in this research for the Ti-15V-3Cr-3Sn-3Al, which presents satisfactory molding performance. Firstly, the effect of heat treatment under varied cooling rates on the relevant mechanical properties and microstructure are studied. Secondly, the material butt-welding are performed by EBW and the TIG welding method respectively to further study the effect of heat-treatment process before and after the welding together with the microstructure and mechanical property investigation of the welded sample. Therefore, the optimal heat treatment parameters can be obtained by the above test results.
The result of the heat-treatment conducted under varied cooling rates shows that, when putting under S.T.+F.C.+A.A. heat treatment conditions, enhanced tensile strength could be obtained while still having good elongation. The result of the Butt-welding also indicated that the pre-welding heat treatment would not bring a visible effect to the mechanical properties. However, the needle-type -phase precipitate from grain interior through the post-welding heat treatment can enhance the hardness and strength of the welding subject at the expense of elongation reduction.