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Aluminium alloys AA5XXX and AA6XXX have low density and high yield strength and are frequently used to make air, sea, and land vehicles/technology lighter. Different types of aluminium alloys need to be adaptively assembled together. Therefore, it is important but difficult to weld aluminium alloys. This study investigated the microstructural and mechanical properties of two dissimilar aluminium alloys, AA5754 and AA6013, which were welded using gas metal arc welding (GMAW) and friction stir welding (FSW). Hardness, tensile, bending, and fatigue tests were done on the welded samples. The test results were evaluated and interpreted according to the literature. The weld zone (weld metal, HAZ) of AA5754 and AA6013 aluminium alloys joined by GMAW and FSW showed significant differences. The highest tensile strength and fatigue life were obtained from the FSWed sample after the base metals. The welded samples joined using both welding methods were successfully deformed by 180 degrees without damaging their upper or lower surfaces. 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 funding KBUBAP-17-DR-406. WOS:000703518600005 2-s2.0-85115799400

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.

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.

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.

Bachelor thesis covered with unbreakable connection of metals using fussion arc welding and laser welding of iron alloys and other alloys. Here is made an analysis of welding methods MIG, MAG, TIG, coated electrode, laser welding and plasma wel-ding. The substances of these best known methods are described with their deployments in mechanical industries. In the last part of thesis is paid attention to addition products and their actions on the microstructure of weld. Illustrative pictures and metallographic cut complete this thesis.

Bu tez çalışması Batman Üniversitesi Bilimsel Araştırma Projeleri Birimi (BTÜBAP) tarafından 2017-DOKTORA-2 nolu proje ile desteklenmiştir., Doç. Dr. Yahya Hışman ÇELİK bu tez çalışmasının eş danışmanıdır., Alüminyum ve alaşımları; düşük yoğunluk, yüksek mukavemet, iyi korozyon direnci ve iyi kaynak kabiliyeti gibi özeliklere sahip olduğundan dolayı günümüzde en yaygın kullanılan yapı malzemeleridir. Alüminyum ve alaşımları, ergitme esaslı ve basınç esaslı (katı faz) kaynak yöntemleri ile birleştirilebilmektedirler. TIG ve MIG kaynak yöntemleri en çok tercih edilen ergitme esaslı kaynak yöntemleridir. Ancak ergitme esaslı kaynak yöntemlerinde yüksek ısıdan dolayı kaynak metalinde bazı metalurjik problemler oluşmakta ve bu durum kaynaklı bağlantılarda mekanik özeliklerin zayıflamasına sebebiyet vermektedir. Bu amaçla, alüminyum ve alaşımlarının kaynağı için ergitme oluşturmaksızın gerçekleştirilebilecek bir yöntem arayışı sonucu İngiliz Kaynak Enstitüsü tarafında Sürtünme Karıştırma Kaynağı (FSW) bulunmuş ve geliştirilmiştir. Böylece alüminyum plakaların alın alına birleştirilmesi için FSW yöntemi de kullanılmaya başlanmıştır. Bu yöntem ergitme esaslı kaynak yöntemlerine göre birçok avantaj sunmaktadır ve başarılı uygulamaları sayesinde havacılık, uzay, denizcilik, otomotiv, raylı ve zırhlı taşıt endüstrilerinde kullanım alanı bulmaktadırlar. Bu çalışmada, farklı özelliklerdeki AA7075 ve AA5182 alüminyum alaşım plakaları TIG, MIG ve FSW yöntemleriyle birleştirilmiştir. TIG ve MIG ile yapılan birleştirme işlemlerinde farklı amper (130, 140 ve 150 A) değerleri ve iki farlı kaynak ağzı (V ve X) kullanılmıştır. FSW kaynağında ise farklı dönme devirleri (980, 1325 ve 1800 dev/dk), kaynak ilerleme hızları (108 ve 233 mm/dk) ve iki farklı geometriye sahip karıştırıcı uç (konik helisel ve üçgen) kombinasyonları kullanılarak kaynaklar yapılmıştır. Kaynaklı bağlantıların mikroyapıları optik mikroskop ve taramalı elektron mikroskobu (SEM) ile incelenmiştir. Her kaynaklı plakadan çıkarılan numunelerin kaynak bölgesindeki Vickers sertlik ölçümleri yapılmıştır. Ayrıca kaynaklı plakalardan alınan deney numunelerine çekme ve yorulma testleri uygulanmıştır. Çekme testi sonrası oluşan kırılma yüzeyleri ve olası kaynak hataları SEM ile analiz edilmiştir. FSW yöntemi ile birleştirilen kaynaklı bağlantılarda, kaynak esnasında birleşmenin alüminyum alaşımlarının ergime sıcaklığı altındaki bir sıcaklıkta gerçekleşmesi ve birleşme bölgelerinde daha az boşluklu mikroyapı oluşumu bu kaynaklı bağlantılara ait mekanik özeliklerinin TIG ve MIG kaynaklı bağlantıların mekanik özeliklerinden daha iyi olmasına katkı sağladığı görülmüştür. En iyi mekanik özellikler FSW yönteminde 980 dev/dk dönme devrinde, 108 mm/dk kaynak ilerleme hızı ve konik helisel kanala sahip karıştırıcı ucun kullanıldığı deneylerde elde edilmiştir. Bu değerler çekme testi için 264,7 MPa, yorulma testi için ise 158,8 MPa'dır. Sertlik değeri ise bir birine oldukça yakın olup dönme devrine bağlı olarak değişiklik göstermiştir. En yüksek sertlik 1325 dev/dk dönme devrindeki bağlantıda 87 HV olarak elde edilmiştir., Aluminum and its alloys are the most commonly used building materials today because of their properties such as low densities, high strengths, good corrosion resistance and good weldability. Aluminium and its alloys can be joined with melting-based and pressure-based (solid phase) welding methods. TIG and MIG methods are the most preferred welding methods based on melting. However, due to the high temperature in melting-based welding methods, some metallurgical problems occur in the weld metal, which causes the mechanical properties to weaken in the welded joints. For this purpose, friction stir welding (FSW) has been found and developed by the British Welding Institute in the result of method research, which can be carried out without melting, for the weld of aluminium and its alloys. Thus, FSW method is also started to use for joining to the forehead of aluminium plates. This method offers many advantages over melting-based welding methods, and thanks to its successful applications, it finds usage area in the aerospace, space, marine, automotive, railway and armoured vehicles industries. In this study, AA7075 and AA5182 aluminium alloy plates in different specifications were joined by TIG, MIG and FSW methods. Different amperes (130, 140 and 150 A) values and two different weld groove (V and X) were used in joining with TIG and MIG. At the FSW, welds were made using different rotation speeds (980, 1325 and 1800 rpm), welding feed rate (108 and 233 mm/min) and stirred tips having two different geometries (conical helical and triangular). Microstructures of welded joints were investigated by an optical microscope and scanning electron microscope (SEM). Vickers hardness measurements were made in the weld zone of samples removed from each welded plate. Tensile and fatigue tests were also applied to the test specimens from welded plates. After the tensile test, the fracture surfaces and possible welding defects were analysed by SEM. In welded connections joined with the FSW method, it has been seen to contribute that the mechanical properties belonging to these welded joints better than the mechanical properties belonging to the TIG and MIG welded joints. Because the weld carried out at a temperature below the melting temperature of the aluminium alloys, and the microstructure had less porosity. The best mechanical properties were obtained from FSW method in a rotational speed of 980 rpm, a feed rate of 108 mm/min, and a stirrer tip having conical helical. These values are 264.7 MPa for tensile test and 158.8 MPa for fatigue test. The hardness value was very close to each other and varied depending on the rotation speed. The highest hardness was obtained as 87 HV at the connection at 1325-rpm rotation speed.

In this master thesis different overlay welding methods suitable for boiler application has been investigated. The purpose of this project is to define advantages and disadvantages for each overlay welding methods and suggest some evaluation criteria on some commercial and experimental alloys aimed for overlay welding material. Many components in a boiler are made of low alloy steel and the atmosphere in the furnace region can be very complex; therefore many different types of corrosion can occur. Weld overlay is a process where one or multiple layers of corrosion resistant material are applied to a base material. The two overlay welding methods investigated in this study were Tungsten Inert Gas welding and Metal Inert/Active Gas welding. Tests were performed with FeCrAl alloys (Kanthal A, Kanthal D and some experimental alloys). FeCrAl alloys in general are ferritic iron-based steels with a typical concentration of 20-23 wt. % chromium and ~5 wt.% aluminum. Different overlay welding evaluation was made; visual examination, dye penetrant inspection, macro/micro examination, side bend test and short term corrosion test (~50hours). Conclusion of this thesis is that MIG welding is a more productive method than TIG, but more defects such cracks and lack of fusion can be produced for MIG welding. These defects can be “fixed” if welding parameters is optimized. If repairing a certain place TIG welding is a better option. A conclusion about number of layers; one layer with MIG welding is almost as thick as three layers with TIG welding with welding wire Ø 1mm. Three welding evaluation that is really important is visual examination, dye penetrant testing and corrosion test in order to choose which overlay welding method is suitable in boiler application. I detta examensarbete har olika påsvetsningsmetoder som är lämpliga för en pannapplikation undersökts. Syftet med denna studie var att undersöka både för- och nackdelar med påsvetsningsmetoderna och föreslå några utvärderingskriterier på vissa kommersiella och experimentella legeringar som lämpar sig för påsvetsningsmaterial. Många komponenter i en panna är tillverkade av låg legerat stål och miljön där förbränningen sker kan vara väldigt komplex, därför kan det ske korrosion. Påsvetsning är en process där ett eller flera skikt av ett mer korrosionsbeständigt material appliceras på ett basmaterial. De två olika svetsmetoderna som undersöktes i denna studie var TIG-svetsning och MIG-svetsning. Testerna utfördes med FeCrAl legeringar (Kanthal A, Kanthal D och vissa experimentella legeringar). FeCrAl legeringar är i allmänhet ferritiska järnbaserade stål med 20-23% krom och ~5% aluminium. De utvärderingsmetoderna som undersöktes var: visuell undersökning, penetrantprovning, makro/ mikroundersökning, sidobockprovning och korttidskorrosionstest (~50 timmar). Slutsatsen av detta examensarbete är att MIG-svetsning är en mer produktiv metod än TIG, men fler defekter såsom bindfel och sprickor uppkom för MIG-svetsning. Dessa defekter kan ”fixas” genom optimering av svetsparametrar. Om man bara ska reparera ett specifikt område är TIG-svetsning ett bättre alternativ. En slutsats om antal lager är att ett lager med MIG-svetsning är nästan lika tjockt som tre lager med TIG-svetsning med Ø 1mm svetstråd. Tre svetsutvärderingar som är viktiga är visuell undersökning, penetrantprovning och korrosionstest för att välja vilken påsvetsmetod som är lämpligast i pannapplikation.

Hybrid welding of stainless steels or aluminium alloys was performed with the heat sources of YAG laser and TIG, or YAG laser and MIG, respectively. The effects of welding conditions and melt flows on penetration depth, geometry and porosity formation were investigated with the X-ray transmission real-time observation method. Melt flows on penetration depth and geometry were consequently confirmed. Concerning porosity suppression, in TIG-YAG hybrid welding of stainless steel, no formation of bubbles was attributed to the absence of pores. On the other hand, disappearance of bubbles from the concave molten pool surface due to the arc pressure played an important role in reducing porosity in YAG-MIG hybrid welding of aluminium alloys at high arc currents.

U teorijskom dijelu rada navedeno je označavanje aluminijskih legura s obzirom na legirne elemente i stanja u kojima se nalaze, te glavna podjela sa svojstvima aluminijskih legura prema toplinskoj obradivosti. Opisani su postupci zavarivanja aluminijskih legura s naglaskom na TIG i MIG postupak koji se najviše primjenjuju, navedeni su zaštitni plinovi, te izbor dodatnih materijala koji bitno utječe na svojstva zavarenih spojeva. Analizirana je zavarljivost toplinski obradivih aluminijskih legura, te su opisane osnovne karakteristike zavarenih spojeva i glavni mehanizmi koji narušavaju mehanička svojstva i integritet spojeva. Navedena je primjena aluminijskih legura s primjerima iz proizvodnje. U eksperimentalnom dijelu odabrana je prikladna tehnologija zavarivanja aluminijske legure AW 6082 i dodatni materijali kojima bi se reduciralo smanjenje čvrstoće i pojava pukotina u zavarenim spojevima. Provedeno je sučeono zavarivanje radnih komada impulsnim MIG postupkom zavarivanja s ciljem usporedbe dva različita dodatna materijala, ER4043 i ER5356. Na zavarenim uzorcima provedena su mehanička ispitivanja, na savijanje i statički vlačni pokus, te su obavljene makroanaliza i mikroskopska analiza uzoraka s ciljem uvida u strukturu i svojstva zavarenih spojeva. U konačnici su donijeti zaključci o mogućim alternativama tehnologije i dodatnim materijalima kojima bi se poboljšala mehanička svojstva zavarenog spoja. The theoretical part of this thesis covers the designation of aluminum alloys according to their conditions, alloying elements and in respect to their heat treatability. The thesis also covers the procedures of welding aluminum alloys with emphasis on TIG and MIG processes, shielding gases and a selection of filler materials which have a significant impact on welded joints properties. Weldability of heat treatable aluminum alloys has been analyzed and even basic characteristics of welded joints and mechanisms that may impair mechanical properties and integrity of some alloys have been covered along with the usage of aluminum alloys supported by practical examples. A suitable welding technology has been chosen for welding aluminum alloy AW 6082 together with filler materials which would reduce strength and the occurrence of cracks in the welded joints. Using the pulse MIG procedure, workpieces have been butt welded in order to compare filler materials ER4043 and ER5356. A variety of tests were carried out on the welded specimens like mechanical tests, bending and tension tests together with macro and micro analysis with the purpose of gaining insight into the structure and properties of welded joints. At the end, conclusions about possible alternative technologies and filler materials which could enhance the mechanical properties of welded joints have been brought to light.

This study responds to an industrial demand of repair using an arc welding process. It concerns an aeronautical piece made in 6061 aluminium alloy. The first part of the study is devoted to the comparison of processes Metal Inert Gas (MIG), pulsed MIG, Tungsten Inert Gas and MIG Cold Metal Transfer (CMT). It is the latter process that was selected for its special abilities, such as its good control of parameters and the low damaging produced in the base metal. Then, two filler alloys were tested – 5356 and 6061 aluminium alloys– with two repairing strategies : welding and building up. The results of mechanical tests showed that building up with aluminum 5356 is most suitable option for this application. The trials on the real piece showed the relevance of this approach.The heat affected zone generated by the arc welding process in the 6061 base metal was also characterized. It was shown a varaition of microstructure associated with the change of mechanical properties in this zone. Finally, exploratory trials of homogeneous arc welding, i.e., with the 6061 filler alloy showed that it was possible, with certain conditions, to weld without generating weld cracking, although, this aluminium is deemed unweldable by this way.; Cette étude répond à une demande industrielle de réparation d’une pièce aéronautique en alliage d’aluminium 6061 à l’aide d’un procédé de soudage à l’arc. La première partie est consacrée à la comparaison des procédés Metal Inert Gas (MIG), MIG pulsé, Tungsten Inert Gas et MIG Cold Metal transfer (CMT). C’est ce dernier procédé qui a été sélectionné pour ses aptitudes particulières, comme son bon contrôle des paramètres et le faible endommagement produit dans le métal de base. Puis, deux métaux d’apport ont été testés – les alliages 5356 et 6061 – avec deux stratégies de réparation : le soudage et le rechargement. Les résultats d’essais mécaniques ont démontré que le rechargement avec l’aluminium 5356 est l’option la plus adaptée pour cette application. Les essais sur pièce réelle ont prouvé la pertinence de cette approche.La zone affectée thermiquement générée, dans l’alliage 6061, par les procédés de soudage à l’arc a également été caractérisée. Il a été mis en évidence une variation de la microstructure associée aux changements de propriétés mécaniques de cette zone. Enfin, les essais exploratoires de soudage homogène à l’arc, c’est-à-dire, avec le métal d’apport en 6061, ont prouvé qu’il était possible, dans certaines conditions, de souder sans générer de fissuration, bien que, cet aluminium soit réputé comme étant insoudable de cette manière.

SAŽETAK Rad je podijeljen na četiri osnovna područja. Kroz prvo područje dan je pregled aluminija i aluminijskih legura kao konstrukcijskog materijala. Opisuje se proizvodni proces prerade aluminija iz boksita te je prikazana osnovna podjela i klasifikacija aluminijskih legura prema ASTM-u. Navedeni su čimbenici koji utječu na zavarljivost te je dan prikaz najčešćih nepravilnosti kod zavarivanja aluminija i aluminijskih legura. Kako izbor dodatnog materijala bitno utječe na svojstva zavarenog spoja, prikazan je praktičan primjer izbora dodatnog materijala. Drugo područje daje pregled glavnih postupaka koji se danas primjenjuju pri zavarivanju aluminija i aluminijskih legura. Detaljnije su opisani MIG i TIG postupak jer se primjenjuju u eksperimentalnom radu. Kao postupci opisani su još i plazma postupak, zavarivanje laserom te elektrootporno zavarivanje. Treće područje predstavlja eksperimentalni dio rada u kojem je opisana procedura zavarivanja aluminijske legure EN AW 5083 ( AlMg4, 5Mn ) dobivene lijevanjem. Primijenjeni postupci su MIG i TIP-TIG. Nakon zavarivanja provedena su metalografska ispitivanja te je izveden statički vlačni pokus i ispitivanje na savijanje. U četvrtom djelu obrađeni su rezultati provedenih ispitivanja ; načinjena je analiza i usporedba mehaničkih i mikrostrukturnih ispitivanja te su na osnovu toga doneseni odgovarajući zaključci.

U uvodnom dijelu diplomskog rada, na temelju dostupnih literaturnih podataka, navedene su najčešće upotrebljavane alumijske legure pri izgradnji zrakoplova, te su za svaku leguru navedena osnovna mehanička i fizikalna svojstva, kao i kratak opis upotrebe i zavarljivost legure. U nastavku su analizirani postupci zavarivanja (TIG i MIG), te su navedene najčešće pogreške koje se javljaju pri zavarivanju aluminijskih legura navedenim postupcima. U eksperimentalnom dijelu rada kao osnovni materijal odabrana je precipitacijski očvrstljiva legura 6802. Izvršeno je zavarivanje odabrane legure TIG i MIG postupkom s 2 mješavine zaštitnih plinova. Nakon završene toplinske obrade, pripremljene su ispitne epruvete i obavljena su mehanička ispitivanja. Na kraju su obavljena mikrostrukturna ispitivanja radi analize mogućih grešaka mikrostrukture u osnovnom materijalu, zoni utjecaja topline i samom zavarenom spoju.