Influência do aporte de calor e da velocidade de soldagem na tenacidade da solda HF-ERW

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização microestrutural do metal de solda depositado por arco submerso em chapas de aço-carbono estrutural

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do pré-aquecimento e parâmetros de pulso sobre a microestrutura e propriedades mecânicas de solda em aço ARBL

Pós-graduação em Engenharia Mecânica - FEB

Desenvolvimento de uma EPS especificação de procedimento de soldagem para união de chapas de aço ASTM A131 com processo FCAW

In any welding process is of utmost importance by welders and responsible qualities of the area understand the process and the variables involved in it, in order to have maximum efficiency in welding both in terms of quality as the final cost , never forgetting, of course, the process conditions which the welder or welding operator shall be submitted. Therefore, we sought to understand the variables relevant to the welding process and develop an EPS (Welding Procedure Specification) as ASME IX for cored wire welding process (FCAW Specification AWS) with shielding gas and automated process for base material ASTM a 131, with 5/16 thick, using a single pass weld, for conditions with pre-and post-heating and the destructive testing for verification and analysis of the resulting weld bead

Identificação de causas especiais no processo que aumentam a ocorrência de poro na solda de tubos de aço: aplicação etapas definir, medir e analisar do DMAIC

This work covers the methodology Six Sigma with the application of the steps Define, Measure and Analyze a company of steel tubes, with the objective of identify special causes in the process that drives the creation of the pore defect in the solder. It is highlighted the fact that this work is the base of an continuous upgrade project that aims in eliminating the occurrence of this defect. The motivation is given to the necessity of improving the productivity of the factory, considering that the defect occurs at random and your causes are unknown. This way, it was defined that the problem to analyze, measured the capability of the process in DPMO and analyzed with the aid of graph by attribute P. The results show the process that present special cases, as well as the process considered ideal, This way it was stated that in this work, the processes destabilized and the controlled, allowing a comparison of the characteristics for the elaboration of concise action plans to eliminate the defect. The project must follow the steps Upgrade and control the methodology Six Sigma, in order to ensure success in his execution, aiming to amplify the competitive edge of the business

Caracterização microestrutural de uma estrutura tubular aeronáutica submetida a sucessivos reparos de solda TIG

This work examines the possible effects of successive repair procedures on the microstructure of welded steel SAE 4130 by TIG welding process. Discussions and results were made about the metallographic analysis , non-metallic inclusions and microhardness tests , which were conducted on samples taken from the cradle engine component after the end of its life , a model airplane T-27 Tucano , made by EMBRAER and belonging were performed FAB . The choice of such component is due to the fact that this is critical to flight safety since it provides support for the aircraft engine . Thus regions of the weld metal , base metal and heat affected , with samples of the original weld bead , free of weld bead and also with four rework procedures for TIG welding zone were analyzed . It was found that after the fourth rework there is an increase in the amount of martensite , which may weaken the material with respect to resistance to fatigue. It was also found that the regions of the heat affected zone and weld metal have higher microhardness values when compared to those found in the base metal due to favoring the formation of ferritic and tempered martensite microstructures . Moreover, a welding process promotes a region with less non-metallic inclusions than metal base , which also explains the difference in the results obtained

Alterações microestruturais decorrentes dos sucessivos reparos de solda TIG aplicados ao longo da vida útil de uma estrutura aeronáutica crítica à segurança de vôo

The steel type AISI 4130 (ultra-high strength steel) is an alloy of low carbon and its main alloying elements are chromium and molybdenum, which improves the toughness of the weld metal. It has numerous applications, especially where the need for high mechanical strength. It is widely used in equipment used by the aviation industry, such as cradle-tomotor, and this is the motivation for this study. Cots are of fundamental importance, because the engine supports and maintains balance in the fixed landing gear. This equipment is subjected to intense loading cycles, whose fractures caused by fatigue are constantly observed. Will be determined the effects caused by re-welding the structure of aeronautical equipment, and will also study the microstructure of the metal without welding. The studies will be done on materials used in aircraft, which was given to study. The results provide knowledge of microstructure to evaluate any type of fracture that maybe caused by fatigue. Fatigue is a major cause of aircraft accidents and incidents occurred, which makes the study of the microstructure of the metal, weld and re-solder the knowledge essential to the life of the material. The prevention and control of the process of fatigue in aircraft are critical, since the components are subjected to greater responsibility cyclic loading

Estudo da ocorrência de trinca por fadiga em tubos de aços soldados, devido ao transporte

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Determinação da qualidade da radiografia digital aplicada às soldas de gasodutos e oleodutos terrestres e marítimos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Fabricação de rodas: uma análise comparativa

In our country, the majority of freight and people by road happens municipal, state and federal. Thus, the heavy vehicles like buses and trucks are the main means of transporting people and cargo. This graduate work aims to study the process of manufacturing wheels for trucks, because we can see the lack of literature on the manufacturing process of wheels and also the importance of the processes used to manufacture wheels, such as lamination, stamping, puckering, machining, welding and painting

Estudo do comportamento em fadiga de um tubo de aço API 5CT soldado por resistência elétrica

The oil extraction in deep waters sparked new areas of knowledge, the creation of engineering courses dedicated just to these processes and a wide field of analysisvoiding multiple impacts in case of faults, mainly the economic and environmental. This paper aims to show on the effects and causes of fatigue failure in steel tubes used for oil and gastransportation (linepipe), mainly caused by vortex induced vibrations, or VIV. To make this, through laboratory tests, it found trough the curve Stress versus Number of Cycles, and thus estimating that with a stress value of 350 MPa or less, the fatigue life cycle of the API 5CT T95 (1% Cr) pipe is estimated infinite. It could conclude that the analyzed material has good fatigue failure resistance for offshore use, taking into account only the influence of VIV's, since there are no stress concentrators

Estudo em fadiga no aço API 5L X80 soldado pelo processo HF/ERW

The technological advancement in order to improve the methods of obtaining energy sources such as oil and natural gas is mainly motivated by the recent discovery of oil reserves. So, increasingly , there is a need for a thorough knowledge of the materials used in the manufacture of pipelines for transportation and exploration of oil and natural gas. The steels which follow the API standard (American Petroleum Institute), also known as high strenght low alloy (hsla), are used in the manufacture of these pipes, as they have, with their welded joints, mechanical properties to withstand the working conditions to which these ducts will be submitted . The objective of this study is to evaluate the fatigue behavior in microalloyed steel grade API 5L X80 welded by process HF / ERW . For this, axial fatigue tests to obtain S-N curve (stress vs. number of cycles ) were conducted. To complement the study, it was performed metallographic , fractographic , Vickers hardness tests and tensile tests to characterize the mechanical properties of the steel and check whether the values satisfy the specifications of the API 5L standard . From the fatigue tests , it was concluded that the surface finish influences directly on the fatigue life of the material

Análise macro e micrográfica da liga AA-356 conforme a taxa de resfriamento

The present work aims to study the characteristics of the alloy Al - 7 % Si - 0 , 3Mg ( AA356 ) , more specifically characterize the macrostructure and microstructure and mechanical properties of the alloy ingots AA356 obtained in metal molds and sand molds for power studying the structures through the difference of cooling rates . This alloy is explained by the fact of referring league has excellent combination of properties such as low solidification shrinkage and good fluidity, good weldability , high wear resistance , high strength to weight ratio, has wide application in general engineering , and particularly in the automotive and aerospace engineering . In this work we will verify this difference in properties through two different cooling rates . We monitor the solid solidification temperatures by thermocouples building with them the cooling curve as a tool that will aid us to evaluate the effectiveness of the grain refining because it achieved with some important properties of the alloy as the latent heat of solidification fraction the liquid and solid temperatures, the total solidification time, and identify the presence of inoculants for grain refinement. Thermal analysis will be supported by the study of graphic software “Origin “will be achieved where the cooling curve and its first derivative that is the cooling rate. Made thermal analysis, analysis will be made in macrographs ingots obtained for observation of macrostructures obtained in both types of ingots and also analysis of micrographs where sampling will occur in strategic positions ingots to correlate with the microstructure. Finally will be collecting data from Brinell hardness of ingots and so then correlating the properties of their respective ingots with cooling rate. We found that obtained with cast metal ingots showed superior properties to the ingots obtained with sand mold

Estudo das alterações das propriedades mecânicas em aço A-516 grau 70 soldado e submetido a tratamento térmico de alívio de tensões

Pressure vessels are equipments that require a great care because of their high cost and human life risk in case of fail, and its fabrication methods are different for each manufacturer. Normally, pressure vessels and its parts are fabricated by welding, which may change local properties of metals. The head of a pressure vessel is a very important structural component and it is fabricated by welding and mechanical conformation. Because its excellent mechanical properties, de steel A-516 Grade 70 is often used in manufacturing of large pressure vessels that are subjected to high pressure and temperature, but was verified that its mechanical resistance is decreased when submitted to a tension relief heat treatment. By experience it was defined that before mechanical conformation of the head of a large pressure vessel, the steel should be submitted to a stress relief heat treatment in order to facilitate the mechanical conformation, but there is no quantitative analysis to prove this method and study its possible risks. In the present work the steel A-516 Grade 70 demonstrated a decrease of its mechanical resistance when submitted to a stress relief heat treatment, but keeping above the minimum limit defined in the literature. By other side its ductility was substantially increased, being possible to deduce that the stress relief heat treatment before mechanical conformation is a viable e recommended technique, but with reservations. With the data acquired during the fabrication e preparation of the specimen and the result of the tests, it was possible to elaborate a welding procedure that provides the same results obtained in this present work

Relacao entre o angulo da ponta do eletrodo e a geometria do cordao de solda no processo de soldagem tig

No processo de soldagem TIG (Tungstênio Inerte Gás), um dos fatores que influenciam o formato do cordão de solda é o ângulo da extremidade do eletrodo. Para estudar o comportamento do arco elétrico em função da geometria de ponta do eletrodo e suas conseqüências nos cordões de solda, efetuaram-se soldagens sobre corpos de prova sem deposição de material (bead-on-plate) através de parâmetros controlados e a mecanização do processo. Parâmetros tais como vazão do gás, velocidade de avanço da tocha e comprimento do arco foram testados para verificar a atuação em conjunto com o ângulo do eletrodo. Pela análise metalográfica (macrografia) estudaram-se os perfis dos cordões de solda, verificando-se que o ângulo exerce uma influência significativa na característica do arco tensão-corrente, na largura e profundidade de penetração da solda. Para maiores ângulos de extremidade do eletrodo obteve-se aumento na penetração, diminuição da tensão e largura do cordão de solda para uma mesma intensidade de corrente.