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Welding constitutes a type of permanent joint in the assembly process in the secondary manufacturing industry such as construction for the manufacture of automobiles, aircraft, bridges, tanks, ships, pipes, among others. The objective of this research was to compare the mechanical tensile strength and hardness of welded specimens. The mechanical traction was to evaluate the resistance to breakage of the weld seams by the MIG/MAG process versus the SMAW welding process, on ASTM 36 base material. The hardness was to determine the plastic deformation of the area affected by heat during the fusion process. For this purpose, the universal testing machine was used to determine the stress-strain relationship of each process; while a hardness tester was used for hardness. In this experiment, 12 welded specimens and two non-welded control specimens were used to determine the quantitative deviation of breakage and hardness, with respect to the specimens subjected to experimental tests. To determine the supremacy in mechanical properties, the t-value statistical tool was used. The results indicated that the stress-strain relationship of the specimens showed the same stages and characteristics of elastic and plastic deformation until failure. Likewise, it was found that the MIG/MAG procedure presents higher tensile strength and hardness values than SMAW, so our zero hypothesis that stated that the SMAW process had better mechanical properties had to be rejected. It is concluded that the MIG/MAG welding process has superior mechanical properties than the SMAW process. La soldadura constituye un tipo de unión permanente en el proceso de ensamble en la industria manufacturera secundaria tales como construccion para la fabricación de automóviles, aeronaves, puentes, tanques, barcos, tuberías, entre otros. El objetivo de esta investigación fue comparar la resistencia mecánica a la tracción y dureza de probetas soldadas. La tracción mecánica fue para evaluar la resistencia a la rotura de los cordones de soldadura por el proceso MIG/MAG versus el proceso de soldadura SMAW, sobre material base ASTM 36. La dureza fue para determinar la deformación plástica de la zona afectada por el calor durante el proceso de fusión. Para ello se empleó la maquina universal de pruebas para determinar la relación esfuerzo-deformación de cada proceso; mientras que para la dureza se empleó un durómetro. En este experimento se usó 12 probetas soldadas y dos probeta no-soldadas testigo, para determinar la desviación cuantitativa de la rotura y dureza, respecto a las probetas sometidas a pruebas experimentales Para determinar la supremacía en propiedades mecánicas, se utilizó la herramienta estadística valor-t. Los resultados indicaron que relación esfuerzo-deformación de las probetas presenta las mismas etapas y características de deformación elástica y plástica hasta su rotura. Asimismo, se halló que el procedimiento MIG/MAG presenta mayores valores de resistencia a la tracción y de dureza que el SMAW, por lo que se tuvo que rechazar nuestra hipótesis cero que afirmaba que el proceso SMAW tenía mejores propiedades mecánicas. Se concluye que la soldadura por procedimiento MIG/MAG presenta propiedades mecánicas superiores que el procedimiento SMAW.

The flood of information has saturated the battlespace, and it is imperative that commanders and their staffs are able to sift through the irrelevant information and pull out the actionable information required to make decisions. The objective of the proposed project was to apply Information Design (ID) principles and methods to communicate clear, effective, efficient, and relevant information to decision makers when planning operations in the information environment (OIE). The information received was prioritized according to the CARVER Methodology in order to smartly design information presented to Marine Expeditionary Force Information Group (MIG) commanders. Visual Analytics was the mechanism to present visually appealing information that was clear, engaging, and easily absorbed. The focus of the research centered on the spread of influence within communities of interest discovered through use of the Scraawl software suite. While a useful tool for discovering large amounts of social data quickly, the practical use of Scraawl to the Marine information practitioner would be limited due to classification issues. However, it was found that influence within the analyzed communities spreads rapidly and widely according to experience of the source, physical geography, meaningful and consistent engagements, and media utilized. This thesis showed how effective an open-source tool can be to reduce the cognitive load of the MIG commander, enhancing efficient decision-making. Major, United States Marine Corps Approved for public release. Distribution is unlimited.

The purpose of this work is to validate the thermal welding cycle obtained experimentally with the metal inert gas (MIG) welding process on a 6063-T5 aluminium tubular profile using the finite element method. The assembly formed by the tubular profile and the weld bead obtained experimentally is represented in an accurate way, taking care of both the geometry and the contour of the weld bead. The precision achieved in the numerical-experimental validation carried out by means of the finite element method is due to the care that has been taken in drawing the welded piece together with the weld bead made experimentally. In the validation carried out, the experimental and numerical cooling curves and the critical cooling time between 400 and 300?C (t4/3 ) in both curves are compared.

U okviru ovog diplomskog rada prikazane su osnovne karakteristike i primjena aluminijskih legura s naglaskom na legure serije 5XXX i 6XXX. Prikazane su osnovne značajke zavarljivosti aluminijskih legura kao i pogreške koje mogu nastati prilikom njihova zavarivanja. Također u sklopu teoretskog dijela rada prikazane su osnovne značajke MIG postupka s naglaskom na načine prijenosa metala prilikom zavarivanja aluminijskih legura. Dodatno je opisana primjena konvencionalnih pulsnih struja i prijenosa metala duplim pulsom, kao i dinamičke karakteristike tih dvaju metoda. U eksperimentalnom dijelu rada određena je dinamička karakteristika izvora struje pri zavarivanju aluminijske legure 5083 korištenjem pulsnog prijenosa i prijenosa duplim pulsom. Uz to izvedeni su kutni zavari aluminijskih ploča legure 5086 primjenom dvaju spomenutih načina prijenosa metala, nakon čega su provedena ispitivanja propisana normom HRN EN ISO 15614-2. Na temelju dobivenih rezultata provedena je komparativna analiza konvencionalnog pulsnog postupka i postupka duplim pulsom. Within this thesis, aluminium alloys’ basic characteristics and application emphasising alloys of series 5XXX and 6XXX are presented. The essential weldability characteristics of aluminium alloys and the errors that can occur during their welding are shown. Also, as part of the theoretical part of the paper, the basic features of the MIG process are presented, with an emphasis on the methods of metal transfer during welding of aluminium alloys. The application of conventional pulse currents and double-pulse metal transfer is additionally described with the dynamic characteristics of these two methods. In the experimental part of the paper, the current source’s dynamic characteristic during welding of aluminium alloy 5083 was determined using pulse transmission and double pulse transmission. Besides, angular welds of aluminium plates of alloy 5086 were performed using the two mentioned metal transfer methods after which the tests prescribed by the standard HRN EN ISO 15614-2 were performed. A comparative analysis of the conventional pulse procedure and the double pulse procedure was performed based on the obtained results.

Završni rad je podijeljen u dva dijela, teorijski i eksperimentalni dio. U teorijskom dijelu rada klasificirani su i opisani najčešće primjenjivani postupci zavarivanja u autoindustriji s posebnim naglaskom na elektrootporno točkasto zavarivanje. Analizirani su parametri zavarivanja karakteristični za svaki navedeni postupak, te je dan osvrt njihovog utjecaja na geometriju zavara i kvalitetu samog zavarenog spoja. Navedeni su, također, i najčešće korišteni materijali u automobilskoj industriji, sa slikovnim prikazima dijelova konstrukcije, te je obrazložena zavarljivost pojedinih metala koji su implementirani u konstrukciju automobila. U eksperimentalnom dijelu rada provedena je priprema i elektrootporno točkasto zavarivanje ispitnih uzoraka izrađenih od čelika S235. Nerazornim i razornim ispitivanjem ispitan je utjecaj jakosti struje zavarivanja i vremena predgrijavanja kao promjenjivih parametara zavarivanja na kvalitetu i oblik zavarenog spoja, te je ocijenjena adekvatnost odabranih parametara The thesis is divided into two parts, a theoretical and experimental part. In the theoretical part of the thesis, the most commonly used welding procedures in the automotive industry are classified and described, with special emphasis on resistance spot welding. The welding parameters characteristic to each of these processes are analyzed, and a review of their influence on the geometry of the welds and the quality of the welded joint is given. The most commonly used materials in the automotive industry are also listed, with pictorial representations of parts of the structure. Weldability of metals that are implemented in the car structure is explained as well. In the experimental part of the thesis, the preparation and resistance spot welding of the specimens made of S235 steel was performed. Non - destructive and destructive testing was conducted in order to examine the influence of welding current value and time of preheating as variable welding parameters on the quality and shape of the welded joint. Adequacy of selected parameters was evaluated as well.

The use of aluminum alloys to reduce weight in air, sea, and land vehicles is increasing rapidly, especially due to their low density, excellent corrosion resistance, good forming properties, and increasable mechanical properties. A common aspect of all the relevant industrial sectors is the need to join the many parts of manufactured technological products using welding methods. In these industries, using welding to join different aluminum alloys having high mechanical properties is especially important. However, despite the widespread usage areas, it is very difficult to join different aluminums and their alloys via welding. In this study, AA5754/AA6013 aluminum alloys were joined using automatic gas metal arc welding (GMAW). Welded joints were created at two different welding speeds (150 and 180 mm/min) and three different welding current values (130, 140, and 150 A). This study investigated the microstructural and mechanical properties of AA5754/AA6013 aluminum alloy sheets joined at different welding speeds and current values. The macro and microstructures of samples taken from the welded joints were examined. In addition, hardness, tensile, bending, and fatigue tests were performed on the welded samples. The findings obtained as a result of the tests were evaluated and interpreted in light of the literature. Karabuk University Scientific Research Project CommitteeKarabuk University [KBUBAP-17-DR-406] The authors would like to thank the Karabuk University Scientific Research Project Committee for providing funding for this study (Project No. KBUBAP-17-DR-406) . WOS:000691196000005 2-s2.0-85112379090

Dissertation, RWTH Aachen University, 2021; Düren : Shaker Verlag, Aachener Berichte Fügetechnik 2/2022, 1 Online-Ressource : Illustrationen, Diagramme (2022). = Dissertation, RWTH Aachen University, 2021, Welding is one of the key manufacturing processes in the metal mechanic industry, for this reason, any improvement in quality and efficiency leads to enhanced overall productivity. On the other hand, aluminum alloys are increasingly becoming a fundamental part of the task of reducing the weight of metal structures in means of transport, as a means of reducing CO2 emissions. The union or hybridization between two welding processes as a means of increasing productivity in joint applications is a widely used and studied technique. An alternative hybrid process that is being studied in recent years is the Plasma-MIG process in a tandem configuration. This process is characterized by having a torch arrangement on the same axis (paraxial) with a distance between them. With this configuration it is guaranteed that each one of its processes maintains its unique properties. However, problems and phenomena such as current transfer between the welding arcs which affects the measurement of electrical signals have been vaguely commented on in the scarce literature on the subject. In this investigation the Plasma-MIG in tandem configuration is characterized by gradually bringing their torches closer together in order to observe the behavior of their electrical signals as the arcs are coupled. In addition, the Plasma process is configured with direct and alternating current, in order to observe the need for cathodic cleaning when the hybrid process is used in aluminum alloys. Once the phenomena that occur when hybridizing the processes are known, the interaction between the welding processes is studied, from an energy point of view. The objective is to observe if there is an exchange of current between the welding processes and, if it exists, how this affects the welding processes. The results showed that it is possible to couple the Plasma and MIG processes in a paraxial (tandem) configuration to make aluminum joints, with a stable arc and greater penetration than the single processes. The establishment of a "current path” between the MIG and plasma arcs was noticed, which allows the current flow between the welding process, influencing directly the MIG arc length behavior. Moreover, it was concluded that it is not necessary to configure alternating current in the Plasma process to weld aluminum, because the MIG process does the cathodic cleaning. It was also concluded that an external magnetic field is not necessary to stabilize the behavior of the welding arcs. The joints of 10 and 15 mm thickness presented good surface appearance, although the hybrid process demonstrated superiority only for the 15 mm thick joints., Published by Shaker Verlag, Düren

U prvom (teorijskom) dijelu rada opisan je MIG/MAG postupak zavarivanja zajedno sa parametrima kao i detaljan opis načina prijenosa metala u električnom luku. Naglasak je bio na automatiziranim rješenjima za zavarivanje MIG/MAG postupkom s fokusom na automatima za pravocrtno zavarivanje. Također je dan pregled i opis nekih od postojećih automata na tržištu. Cilj drugog (eksperimentalnog) dijela bio je projektiranje vlastitog automata za pravocrtno vođenje pištolja prilikom MIG/MAG zavarivanja cijevi promjera 500 mm, duljine 1500 mm. Dani su detaljni opisi komponenti zajedno sa svom tehničkom dokumentacijom i popisom dijelova potrebnih za izradu istog. Također prikazan je prijedlog shematske strukture električnog upravljanja za projektirani automat. The first (theoretical) part of the paper describes the MIG/MAG welding process along with the parameters. A detailed description of the methods of metal transfer in an electric arc is included as well. The emphasis was on automated MIG/MAG welding solutions with the focus on straight-line welding machines. An overview and description of some of the existing automated welding machines on the market is also given. The purpose of the second (experimental) part was to design automated welding machine with a straight-line guided gun for MIG/MAG welding of pipes with a diameter of 500 mm and length of 1500 mm. Detailed descriptions of the components are given together with all technical documentation and a list of parts needed to produce it. A proposal of the schematic structure of the electrical control for the designed automated machine is also presented.

Low-voltage compact gyrotron is under development at the University of Electronic Science and Technology of China (UESTC) for industrial applications. Due to the low operating voltage, the relativistic factor is weak, and interaction efficiency could not be high. Therefore, a magnetron-injection gun (MIG) with an extremely high-velocity ratio &alpha, (around 2.5) is selected to improve the interaction efficiency. As beam voltage drops, space charge effects become more and more obvious, thus a more detailed analysis of velocity-ratio &alpha, is significant to perform low-voltage gyrotrons, including beam voltage, beam current, modulating voltage, depression voltage, cathode magnetic field, and magnetic depression ratio. Theoretical analysis and simulation optimization are adopted to demonstrate the feasibility of an ultra-high velocity ratio, which considers the space charge effects. Based on theoretical analysis, an electron gun with a transverse to longitudinal velocity ratio 2.55 and velocity spread 9.3% is designed through simulation optimization. The working voltage and current are 10 kV and 0.46 A with cathode emission density 1 A/cm2 for a 75 GHz hundreds of watts&rsquo, output power gyrotron.

En este estudio se realiza una adaptación del proceso de soldadura por arco eléctrico TIG, del inglés Tungsten Inert Gas, para acomodarlo a una instalación de fabricación aditiva con el objetivo de producir piezas metálicas tridimensionales. La máquina base de fabricación aditiva sobre la que se trabaja es una impresora 3D FDM. Se estudian los parámetros de soldeo adecuados y se diseñan y adaptan todos los componentes necesarios para este proceso de fabricación. También, se diseñan y programan las trayectorias de la máquina. La adaptación realizada sería válida, también, para procesos de soldadura MIG, del inglés Metal Inert Gas, pero deberían introducirse algunos pequeños cambios en el diseño y en la programación (a lo largo de este estudio se explica por qué se ha derivado la adaptación a un proceso TIG). En primer lugar, se muestran las tecnologías de fabricación aditiva más comunes y se definen brevemente. A continuación, se exponen las ventajas de una y otra tecnología. Seguidamente, se introducen los procesos de soldeo por arco eléctrico y se realiza una valoración del método más adecuado para adaptar a la maquinaria disponible. Una vez escogido el método de soldadura, se diseñan todas las adaptaciones necesarias y todo el proceso de fabricación y, finalmente, se procede a realizar unos planes de experimentación que permitirán ajustar la máquina y evaluar la calidad de cada una de las piezas fabricadas. Se describen todas y cada una de las modificaciones y calibraciones necesarias tanto a nivel de Hardware como de Software. Por último, los resultados obtenidos son evaluados y contrastados para inferir mejoras en el conjunto del proceso de fabricación diseñado.

En el sector de la industria, uno de los métodos de construcción y unión de materiales más extendido y consolidado es la soldadura, pero existen infinidad de variantes y procesos, en los cuales hay muchos aspectos a tener en cuenta como: material a soldar, posiciones, gases, dificultad operacional, etc. el trabajo nace de la necesidad de cerrar y clarificar el amplio abanico que hay dentro del campo de la soldadura y que tiene como objetivo analizar y comparar sus principales procesos, encontrar los puntos fuertes y las desventajas, para finalmente optimizar su uso en función de las necesidades. ya existen muchos trabajos en el ámbito de la soldadura, con el objetivo de diferenciar este trabajo de otros, se ha querido hacer una parte teórica donde encontrar los conceptos más importantes a tener en cuenta en la soldadura, como; clasificaciones, normativa, procesos y seguridad, entre otros aspectos, pero de una forma más visual, esquemática y resumida posible. la segunda parte de este trabajo es la práctica, en la que se realizarán una serie de pruebas con los principales procesos de soldeo con distintos metales, tomando una serie de datos antes de la soldadura, para tener todos los parámetros controlados. una vez realizada cada prueba se registrarán los resultados obtenidos con el fin de realizar un estudio económico del coste de cada soldadura, comparar resultados entre ellas con el objetivo de mejorar su rendimiento y reducir costes. finalmente, se extraerán una serie de valoraciones y conclusiones, sobre los datos obtenidos gracias a las pruebas realizadas y a la extrapolación de datos.

Bakgrund: Intensivvård är den högsta vårdinstansen på ett sjukhus, en av sjukvårdens mest resurskrävande behandlingsformer. När en patient blir kritiskt sjuk eller påvisar försämrade vitalparametrar kontaktar vårdpersonalen mobil intensivvårdsgrupp (MIG) som utgår ifrån intensivvårdsavdelningen (IVA). Problemformulering: De kritiskt sjuka patienterna vårdas inte längre bara på IVA men också på vårdavdelningar. I ett omvårdnads- och professionsperspektiv som intensivvårdssjuksköterska är det av betydelse och centralt att förstå orsakerna till kontakt med MIG. Syfte: Att kartlägga kontakter, orsaker och skillnader med mobil intensivvårdsgrupp på ett sjukhus i Västra Götalandsregionen. Metod: En icke-experimentell studie med ett konsekutivt urval och retrospektiv journalgranskning av 386 patientkontakter med MIG under åren 2017–2019. Resultat: Studiens resultat påvisar en hög medelålder. Ingen skillnad återfanns i patientgruppen ur ett könsperspektiv. Den framträdande gruppen är den geriatriska patienten ≥65år som är utsatt och en högriskgrupp vid kontakt med MIG. De utgör majoriteten av alla kontakter med MIG åren 2017–2019. Diskussion: Studiens kartläggning och resultat påvisar behov av kompetenshöjande utbildning och optimeringsteam. Geriatriska patientgruppen behöver vårdinsatser i rätt tid och med rätt kompetens för att minska antalet MIG kontakter och initiera insatser i förtid och motverka svikt av vitala parametrar.

The present research investigates the effects of different welding techniques, namely traditional metal inert gas (MIG), cold metal transfer (CMT), and fiber laser-MIG hybrid, on the microstructural and mechanical properties of joints between extruded EN AW 6181/6082-T6 and cast EN AC 42100-T6 aluminum alloys. These types of weld are very interesting for junctions of Al-alloys parts in the transportation field to promote the lightweight of a large scale chassis. The weld joints were characterized through various metallurgical methods including optical microscopy and hardness measurements to assess their microstructure and to individuate the nature of the intermetallics, their morphology, and distribution. The results allowed for the evaluation of the discrepancies between the welding technologies (MIG, CMT, fiber laser) on different aluminum alloys that represent an exhaustive range of possible joints of a frame. For this reason, both simple bar samples and real junctions of a prototype frame of a sports car were studied and, compared where possible. The study demonstrated the higher quality of innovative CMT and fiber laser-MIG hybrid welding than traditional MIG and the comparison between casting and extrusion techniques provide some inputs for future developments in the automotive field.

O fabrico de materiais com gradiente de funcionalidade reveste-se de algumas dificulda-des pelo que as tecnologias de Fabrico Aditivo constituem uma alternativa interessante. A tecno-logia de deposição directa de energia usando arco eléctrico e fio (WAAM - Wire and Arc Additive Manufacturing) apresenta algumas vantagens, como sejam: baixos custos de equipamento inicial, de funcionamento e de manutenção, elevada taxa de deposição elevada e capacidade de produzir peças com geometria complexa sem defeitos internos. Este trabalho teve como objectivo geral estudar a viabilidade do WAAM para a produção de peças com gradiente funcional depositando alternadamente aço inoxidável 316L e Inconel 625, dois materiais com excelente resistência à corrosão e boas propriedades mecânicas a alta tempe-ratura. Para isso adaptou-se o equipamento de WAAM existente no NTI/DEMI de modo a poder alimentar dois fios na direção do arco eléctrico. Foram feitas deposições com percentagens vari-áveis de cada um dos materiais e variando os parâmetros de processo e estudou-se o efeito destes na qualidade dos cordões depositados. Com parâmetros otimizados, fizeram-se múltiplas deposições sucessivas em altura de modo a construir uma “parede” com gradiente de composição química. Analisou-se a microes-trutura face ao diagrama de equilíbrio de fases e a dureza das amostras. Confirmou-se a viabilidade da utilização do sistema desenvolvido para a deposição de dois fios simultaneamente bem como para a criação de um gradiente de microestruturas ao longo do eixo vertical. Observou-se a existência de carbonetos dispersos confirmados pelos valores de dureza medidos. Na zona mais rica em Inconel, com cerca de 70 at. %, foi detetada uma fissura devida aos diferentes coeficientes de expansão linear do Inconel e do aço inoxidável. Este foi o primeiro estudo deste tipo realizado no NTI, e requer como trabalho futuro a avaliação das propriedades mecânicas e da resistência à corrosão a alta temperatura, entre outras propriedades relevantes para aplicações industriais.