Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-07T00:01:05Z No. of bitstreams: 1 PedroHenriqueSalesDaCosta_DISSERT.pdf: 3167327 bytes, checksum: e3758236165e8d3906f6f8f92e8a236b (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-09T20:11:14Z (GMT) No. of bitstreams: 1 PedroHenriqueSalesDaCosta_DISSERT.pdf: 3167327 bytes, checksum: e3758236165e8d3906f6f8f92e8a236b (MD5) / Made available in DSpace on 2016-05-09T20:11:14Z (GMT). No. of bitstreams: 1 PedroHenriqueSalesDaCosta_DISSERT.pdf: 3167327 bytes, checksum: e3758236165e8d3906f6f8f92e8a236b (MD5) Previous issue date: 2015-08-28 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Em muitos casos o passe de raiz ? uma etapa cr?tica da soldagem, uma vez que sua execu??o ? afetada por diversos fatores, tais como varia??o da abertura da junta, ?ngulo do chanfro, dimens?es da face (nariz) da raiz, inclina??o da tocha, velocidade de soldagem e velocidade de alimenta??o. Al?m disso, a escolha do processo de soldagem ? um fator primordial para garantir a execu??o de um passe de raiz com adequadas propriedades mec?nicas e metal?rgicas. Nesse contexto, este trabalho teve como objetivo estudar a viabilidade dos processos de soldagem MIG-P CC+ e TIG-A aplicado ao passe de raiz em chapas de 200 x 200 x 12,75 mm da liga de alum?nio AA 5052. Para tal, foram analisadas configura??es diferentes de soldagem: o tipo de chanfro (em V e em gola com L=2,00 e 3,00 mm) e dois tipos de metais de adi??o (ER 4043 e 5356). Como metodologia de compara??o, foi determinada a mesma corrente de 150 A e taxa de deposi??o do metal de adi??o Va/Vs = 14, foram realizadas 8 combina??es de par?metros, cada uma com 3 repeti??es, totalizando 24 testes, salientando que foi usada apenas a configura??o de chanfro mais adequada para o TIG-A. S?o apresentados resultados da micrografia e microdureza das zonas fundida e termicamente afetada e n?veis de dilui??o para as juntas soldadas com os distintos metais de adi??o, al?m da radiografia. Nas condi??es estabelecidas neste trabalho, pode-se afirmar que o processo TIG-A apresentou melhores resultados em rela??o ao MIG-P CC+. Em rela??o ? configura??o do chanfro, o que se mostrou mais adequado foi o chanfro em V, para ambos os metais de adi??o e processos. N?o ocorreram defeitos como falta de fus?o, mordeduras e rugosidades. Em rela??o aos n?veis de dilui??o, foram constatados maiores valores quando utilizado o processo MIG-P CC+ para o ER 4043, assim como o processo TIG-A na configura??o de chanfro em V. O metal de adi??o ER 4043 apresentou uma quantidade de poros maior em rela??o ao ER 5356, em ambos os processos. Foi observada ? presen?a de um refino de gr?o, al?m de maiores n?veis de dureza em todas as soldas realizadas com o metal de adi??o ER 5356. / In many cases the root pass is a critical step of welding, since its execution is affected by several factors, such as variation of joint opening, chamfer angle, dimensions of the face (nose) root, torch inclination, welding speed and feed speed. Moreover, the choice of the welding process is a key factor to ensure the execution of a root pass with adequate mechanical and metallurgical properties. In this context, this work aimed to study the feasibility of MIG-P CC+ and TIG-A welding processes applied to the root pass in plates of 200 x 200 x 12,75 mm of the AA 5052 aluminum alloy. For this, different configurations of welding were analyzed: chamfer type(V and collar with L=1,0 and 3,00 mm) and two types of addition metals (ER 4043 and 5356). As compared methodology, It was determined the same current 150 A and the deposition rate of addition metal Va/Vs = 14, they were proposed 12combinations of parameters, each with 3repetitions, totaling 36 tests, stressing that It was used only the most appropriate chamfer setting for TIG-A. Results of micrograph and microhardness of fusion and heat affected zones and dilution levels for welded joints with diferente addition metals, beyond radiography. At the established conditions in this work, it can be said that the TIG-A process showed better results in relation to MIG-P CC+. About the chamfer configuration, which was more appropriate was V chamfer, for both addition metals and process. There were no defects such as lack of fusion, bites and roughness. Relative to dilution levels, higher values were observed when used the MIG-P CC+ process for the ER 4043, as well as TIG-A in the V chamfer configuration. ER 4043 addition metal showed a larger amount of pores in relation to the ER 5356, in both process. It was observed the presence of a grain refining, beyond higher hardness levels in all welds made with the ER 5356 addition metal.

O objetivo deste trabalho é analisar a influência dos parâmetros de um sistema mecanizado de soldagem, composto por uma tocha TIG e outra MAG em tandem, sobre a geometria do cordão de solda resultante. Os resultados obtidos foram comparados com soldas realizadas pelos processos TIG e MAG operando isoladamente. Os testes foram executados por meio de simples deposição de cordões sobre chapas de aço ao carbono AISI 1010 com espessura de 6,3 mm. Os parâmetros analisados foram: corrente de soldagem e distância da ponta do eletrodo até a peça no processo TIG, velocidade de alimentação de arame e tensão do arco no processo MAG, além de velocidade de soldagem e distância entre as tochas. Os cordões de solda foram executados em um dispositivo de soldagem mecanizado, que permite a variação da velocidade de soldagem, distância da ponta do eletrodo TIG e a distância entre as tochas. Os ajustes de corrente e tensão de soldagem foram feitos em duas fontes de potência separadas, ambas do tipo transformador-retificador, uma para cada tocha, devido às diferentes curvas características de cada processo. Através do projeto de experimento fatorial fracionado, foram avaliados os efeitos de dois níveis, um mínimo e outro máximo, mais quatro réplicas dos seus níveis intermediários, resultando em 20 experimentos para cada processo de soldagem. Os valores dos resultados finais indicam uma diferença ao utilizar uma tocha TIG para pré-aquecer o material base, porém, estatisticamente, essa diferença não é significativa entre os processos TIG e MAG em tandem e MAG convencional para a faixa de parâmetros de soldagem adotada. / This study aims to investigate the influence of process parameters of a mechanized welding system, comprising a GTAW torch and a GMAW torch in tandem configuration, on the geometry of the resulting weld bead, performed using GTAW and GMAW welding processes in tandem. The results were compared with weld beads performed by conventional GTAW and GMAW welding processes. The tests were conducted performing bead-on-plate deposits over AISI 1010 6,3 mm thick carbon steel plates. GTAW current, GMAW wire feed speed, GTAW arc length, GMAW voltage, welding speed and the distance between GTAW and GMAW torches were the analyzed parameters. The weld beads were performed in a mechanized welding bench, which allows the variation of speed, distance between torches and arc length of the GTAW torch. Current and voltage adjustments were made in two separate transformer-rectifier power sources, one for each welding torch, due to their different characteristic curves of each process. Through the fractional factorial design of experiment, the effects of two different levels for each parameter were analyzed, plus four replicates of the average values of these levels, resulting in 20 experiments for each welding process. The results show a difference on the weld bead geometry using a GTAW torch to preheat the base metal, however, this difference is not statistically significant between GTAW and GMAW welding process in tandem and GMAW welding process for the adopted range of welding parameters.

Os processos de soldagem Metal Inert Gas (MIG) e Tungsten Inert Gas (TIG) são utilizados na soldagem de estruturas de alumínio. Este estudo tem como objetivo geral desenvolver um processo otimizado para soldagem em estruturas de alumínio, com qualidade e produtividade. Especificamente busca determinar os parâmetros de soldagem e obter, assim, o melhor desempenho possível no que se refere à produtividade, a qualidade na soldagem e propriedades mecânicas. Foram feitos corpos de prova de estruturas de alumínio 6351 T6 NBR ISO 209-2010 pelos processos de soldagem TIG e MIG, sendo caracterizadas por macrografia e resistência à tração. Com base na análise do software minitab foram obtidos os melhores parâmetros para o processo TIG sendo 180 A, vazão de 12 l/min e para o processo MIG, foram 170A e 23 Volts. Com esses novos parâmetros conseguiu-se aumentar a produtividade em 30%. Para o critério de resistência, tanto o processo MIG como o processo TIG, atenderam a especificação da norma AWS D1.2. / The welding processes Metal Inert Gas (MIG) and Tungsten Inert Gas (TIG) are used in the welding of aluminum structures. This study aims to develop an overall optimized process for welding aluminum structures, with quality and productivity. Specifically, attempts to determine the welding parameters and thus obtain the best possible performance in terms of productivity, quality welding and mechanical properties. Specimens were made of aluminum structures 6351 T6 NBR ISO 209-2010 by the welding processes TIG and MIG, being characterized by Macrography and tensile strength. Based on the analysis of the minitab software best parameters were obtained for the process being TIG 180 A and flow rate 12 l / min and the MIG were 170A and 23 Volts. Through these new parameters we were able to increase productivity by 30%. For the criterion of resistance, both process the MIG and TIG, attended the specification of AWS D1.2 norm.

This thesis deals with the study of influence of preheating/reheating by TIG arc method in the laser welding process of Domex 700 MC fine-grained steel through the evaluation of laser-welds properties, respectively properties of welds made by laser-TIG hybrid technology. The main part of this thesis is experiment, in which Domex 700 MC plates 3 mm thick were welded – first using laser itself, then using laser with arc preheating and finally using laser with arc reheating. The variable parameter during the processes preheating or reheating was distance of TIG tungsten electrode and laser beam (DLA = 1 mm, 2 mm and 4 mm). The criterion for the assessment of welds properties thus produced was tensile strength verified by the tensile test. For a more detailed study of the laser-welds properties, a macrostructure / weld microstructure analysis and a Vickers hardness test were performed.

In this thesis is studied the influence of arc TIG preheating during laser welding of 2 mm Hardox 450 material sheets. This material achieves its good mechanical properties by processes of heat treatment. That causes problems during welding because of heat degradation. Experimental sheets were welded within various configurations of welding parameters and positions of TIG nozzle. Testing specimens were cut out by laser and were used for tension testing, Vickers hardness testing and metallographical testing (macro and microstructure). The results of using the second heat source are: wider heat affected zone, smoother transitions among its zones, reduction of toughness and hardness, finer grain structure and occurring ferritic microstructure. This hybrid technology, combination of laser welding and TIG preheating, is very productive creating joints with greatly good quality. The thesis also contains a comparison with common MAG welding method.

The diploma thesis deals with the qualification of welding process of aluminum alloy EN AW-5083 H111. This aluminum alloy was used to make a Venturi tube. Therefore, a literature review has been developed dealing with the properties and use of aluminum and its alloys. The next chapter deals with the weldability of aluminum, aluminum alloys and the weldability of EN AW-5083 alloy. Part of the work is devoted to the used TIG method and its specifics when welding aluminum materials. The practical part of the thesis deals with the actual qualification of welding procedures according to the relevant standard and evaluation of production conditions according to the product standard. The last chapter deals with the overall manufacturing process of the Venturi tube.

This Diploma thesis presents possible proposals of welds number reduction frame doors for rail vehicles welded from profiles from aluminium alloy EN AW 6060, which is heat treated by temper T66. Profiles are welded by TIG process with additional material S Al 5087 (AlMg4,5MnZr). The heat treatment by the welding cycle causes a change in structure of basic material and decrease of mechanical properties due to dissolution of precipitates. To measure the necessary mechanical properties of the material after welding a tensile test was performed on the delivered samples. The resulting values from tensile test were subsequently used as cut – off values in the new door frame design by FEM simulation in Virtual Performance Solution software with PAM – Crash extension. The newly designed frame was welded according to the necessary welding procedure specifications, which are also part of the thesis. The conclusion is devoted to the economic evaluation of the current and new design of the door frame.

Different problems arise from choice of setting technological parameters during welding of alluminium alloys. Choice of welding method, welding speed and material influence mechanical properties of welds. During welding of alluminium alloys come difficulties due to oxidation of thin surface layer of material. One of ways how to overcome this obtacle is to use hybrid laser-TIG welding method. In this diploma thesis is described influence of welding processes on mechanical properties of two alluminium alloys(EN AW-5754 H22, EN AW-6082 T6) and change in their microstructure during welding.

This thesis deals with the usage of arc preheating for welding high strength boron enhanced steel 22MnB5 using hybrid technology known as laserTIG and also its impact on the final weld compared to welds welded by only the laser or the arc method. During the experiment I welded five sheets of the above mentioned steel 1,3 or 1,9 milimeters wide. Except for the welds fabricated by the laser and the TIG method was the only variable the electric current of the arc (I = 20, 40, or 60 A). Welds welded this way were compared based on strength limits measured by the tensile tests. Additionally were they compared according to the metalographic survey and the progress of weld hardness, calculated using the Vickers hardness test.

The diploma thesis deals with the issue of surface treatment by pickling. In the research part the pickling technology is described in detail. The next chapters are focused on the TIG welding method and the weldability of austenitic stainless steels. In the experimental part an experiment is carried out focusing on the comparison of weight loss and surface quality depending on the pickling time. Part of the conclusion is the implementation of pWPS documentation for the specified component and a brief manual for customers of pickling plant.