Estudo da influência da aplicação do fluido de corte no torneamento da liga de alumínio AA7075

One of the ways to minimize the effects of unproductive time caused by tool wear can be achieved by introducing an efficient system of lubrication and cooling in the process. However, in the last decade the research had the goal to restrict the maximum use of refrigerants and / or lubricants in metal-mechanical production. The important factors that justify this procedure include the operational costs of production, ecological issues, and the legal requirements of environmental conservation and preservation of human health. The purpose of the proposed work is the study of machining by turning with the focus on the influence caused by the application of cutting fluid in several ways of application (abundant and MQF) and also by comparing the results obtained by machining without the presence of fluid . For this purpose, the turning tests are conducted using an aluminum alloy (AA 7075). The response variables to be analyzed were obtained from the roughness (Ra and Ry), the stresses presented (VB) and their progression in relation to the cutting length achieved, the type of chip formed, in addition to changes in the degree of finish (roughness) presented by the turned parts. The results of this study should provide more detailed information about the actual influence of cutting fluids in turning this alloy, which are characterized by high rates of deformation when the formation of damaging your chip machining and also the quality of surface generated. Therefore, it is expected to provide subsidies to promote the optimization of machining this alloy making the most of the role of cutting fluid

Estudo das propriedades mecânicas do aço SAE 1312 modificado ao nióbio

The study of mechanical properties of high-alloy special steels is of great interest of the steel industry due to the great demand by companies that manufacture automotive components of high criticality, and also because of its high commercial value. However, the development of this type of alloy metals demand highly technical knowledge. Among these extremely important kinds of steel, the subject which is the interest of this study is the special steel modified by niobium. The manganese and niobium are the main alloying elements in the composition of these steels, both of them increase the stability of the austenite region, however, manganese increases the hardenability and tensile yield strength, and niobium increases the mechanical strength and promotes refining the grain. The mechanical characterization of steel SAE 1312 modified the niobium was made in order to gain a better understanding of the influence on the mechanical properties caused by aging at different temperatures and for different reductions in the drawing of gauge material. This characterization was made by means of tensile test and hardness. This material showed an increase in yield strength and hardness when gauge with large reductions during the wiredrawing, but when subjected to aging temperatures higher than 300 ° C had a slight loss of these properties

Avaliação da influência da taxa de resfriamento posterior ao tratamento térmico nas propriedades mecânicas do aço API 5L X70

In this work a study about the mechanical properties of the API 5L X70 steel, with or without heat treating, has been made, with the intetion of assess the influence of cooling after the austenitization heat treating by air cooling (normalizing) and a rapid cooling with oil (tempering). This steel is known by high strength and ductility values and it is commonly used in the manufacture of oil pipes. The growing energy demand encouraged the study and manufacture of this material. Although this microalloyed dispense subsequent heat treatings, it was proven that its implementation is very advantageous for this type of application, improving hardness and plastic stability. It was also assessed that the faster the cooling rate is, the better will be these properties

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

Usinagem da liga de níquel inconel 718 com pastilhas de cerâmica

The machining of super alloys resistant to high temperatures such as nickel alloys, inconel 718 specifically, is a very difficult job to obtain improvements in the process, due to the difficulty of machining at high cutting speeds, the use of these alloys in industries showed great developments in recent years, its application in aeronautical industry spread being used in vane turbo, compressor parts, props and set elements. The automotive, chemical, medical and others also took advantage of the great features of inconel 718 and has used the material. The high temperature resistant alloys have high machining difficulty, a fact that is associated with high cutting forces generated during machining which result in high temperatures. High levels of temperatures can cause deterioration of the cutting edge, with subsequent deformation or breakage, wear most common obtained in machining such materials are flank wear the formation of built-up edge for cutting and notch wear. The experimental part of the work consists in machining of nickel-based alloy Inconel 718 heat treated for hardness, using a tool based ceramic silicon nitride Sandvik (Si3N4) in order to compare the best results obtained in the master's thesis of SANTOS (2010) who used a tool ceramics also the basis of silicon nitride which was developed in the doctoral thesis of SOUZA (2005). Assays were performed on a CNC lathe and was noted for each cutting edge results obtained. Tests were made starting from an initial condition of the tool with cutting speed of 200 m/min, feed 0.5 mm and 0.5 mm depth of cut was reduced cutting speed for the subsequent tests with the same conditions of feed and depth of cut. The tool presented wear instant under two 200 m/min and 100 m/min, premature rupture of 50 m/min and finally cut provided with difficulty... (Complete abstract click electronic access below)

Caracterização estrutural da Liga Al-1% Si

The aim of this study is to characterize the macrostructure and microstructure of Al - 1%Si alloy obtained in sand and metallic molds. Aluminium has good mechanical properties, but adding silicon, even in small quantities, can change the microstructure and improves mechanical behavior. Workpieces were castings in metallic and sand molds and one can see a difference in their cooling curve, macroscopic and microscopic structures. The sand mold casting has lower cooling rate and so its grains are larger. Due to the lower concentration of grain boundary, the hardness is lower compared to that found in metallic molds, which has smaller grains and a higher hardness. Therefore, it can be concluded that the cooling rate and alloying elements affect the final microstructure of the workpiece

Análise da curva de resfriamento da liga de alumínio AA 356

It is very important to study the macrostructure of a material in the crude state of solidification due to influence the mechanical properties, as well as the study of their cooling curve. In the present work was to study the alloy AA 356, its macrostructure and its cooling curve. The material was cast in two different molds, a sand and other metallic. In this paper we study the differences in its macrostructure and its cooling curves. In macrostructure can observe the absence of the three zones of solidification and the presence of large pores because of moisture in the sand. In the sample taken from the metal mold can observe the three zones of solidification: a coquilhada, columnar and equiaxed

Estudo da influência do agente nucleante )ALTi5%B1%) na microestrutura de chapas AA8011 obtidas por lingotamento contínuo

The aluminum includes several properties with excellent relation between weight and mechanical resistance. With technological advances, increasingly demand the development of new alloys and other production processes in order to reduce the cost of production and insert these new alloys in broader applications. The process of continuous caster (TRC promoted the unite of the aluminum smelting process with the first stage of rolling, making it most economical through the merger these two phases besides transform the continuous casting process. The AA8xxx series is one of the most versatile aluminum alloys and the most often used in continuous caster process provided a great potential application in the market. In order to further, optimize the process it is necessary to increase awareness of the aluminum solidification phenomena associated with the addition of grain refiner, and control of some aluminum production parameters in the process (production rate, metal temperature, etc.). In this study, AA8011 alloy samples were taken in the raw state obtained by the continuous casting process. The samples were laminated to a thickness of 7mm during the process itself and analyzed at three points along its width by microstructural analysis throughout its thickness, the variation rate of addition of the grain refiner in order to assess the influence of this addition with crystallographic formation and some formation of intermetallic precipitates during the solidification. Through this work, it was possible to improve the knowledge related to the addition of refiner with the monitoring of these production processes

Analise comparativa do desempenho de ferramentas no torneamento do aluminio 2024

The aluminium alloys are used in many fields because of their versatility combined with the excellent aluminium’s properties, mentioned in the study. This study aims to compare the performance of polished Hard Metal, Hard Metal covered with TiB2 and High Speed Steel (HSS) tools, at the aluminium 2024 alloy’s turning, as a function of variation of some turning parameters such as: feed, depth of cut and cutting speed; and study the surface finish and the required power during turning by processing the output data, like analyze the chip’s features for each used tool. The results provide information of the tool’s material effects, when submitted to different turning conditions, about the output variable in question. In this way, it was possible to notice that although the Hard Metal covered with TiB2 tool has provided the better surface finish, the chip’s features were better when the turning was accomplished by the Polished Hard Metal tool. In relation to the required turning’s power, the lowest consumption occurred with the High Speed Steel tool

Estudo do efeito do processo de shot peening na taxa de propagação de trinca por fadiga na liga aeronáutica 2024 - T3

Pós-graduação em Engenharia Mecânica - FEG

Análise da pulsação térmica do processo TIG na soldagem da liga AA6063T6

Pós-graduação em Engenharia Mecânica - FEB

Análise da reversão do fundo de latas de alumínio para bebidas - Buckle

This work approaches the main methods of plastic deformation of metals, with a focus on the deep drawing process. The mechanical properties were evaluated with the tension tests. It is presented the aluminum alloys designation, followed by applying heat treatments and the designation of tempers. The manufacture of aluminum beverage cans is described step by step, in general terms. The main objective is to analyze how different cans background geometries have great influence on the dome reversal. To be able to achieve the goal it was necessary to use cans of different manufacturers, which were used in buckle tests to obtain the reversal pressures, tensile tests and geometric analysis. Finally empirical equations were obtained correlating these variables, and it was observed that the conformation of reforming change significantly it's behavior

Caracterização do fator de intensidade de tensão em corpos trincados através do método dos elementos finitos

The industry generally has sought materials with high mechanical resistance, low density, thermal stability and corrosion resistance. In the aerospace industry, for example, the use of aluminum alloys, such as Al 2024-T351 and Al 7075-T7351, have become essential. However, the use of these materials often do not resulted in a satisfactory performance of the component, since the presence of cracks can cause total rupture of the component, even with a tension below the yield stress of the material, unexpectedly. In this work, these aluminum alloys were analyzed and samples were modeled by the finite element method. Moreover, in the models were applied two different types of cracks, central and edge crack, a vertical force was applied to result in a tension 70% of the yield stress of the material analyzed. Through stress asymptotic distribution in the region near the crack tip were calculated the values of the stress intensity factors for each crack length, after the stress intensity factors characterized were compared graphically with the values of fracture toughness found in the available literature

Estudo da fadiga em liga de alumínio aeronáutico 7475-T761

This work will address the study of fatigue conditions with constant load in an alloy of aluminum analysis 7475 - T761, so we can better understand the conditions of the aircrafts which contain this alloy in their structures. A literature review, which was discussed the concepts of fracture mechanics, fatigue, aeronautical components, chemical analysis of aluminum alloys, fatigue problems that appears in the aircrafts, metallographic analysis, and testing of optical microscopy tensile, fatigue and microhardness, surface analysis (MEV) study of the chemical composition of the alloy in question, the main causes of crashes, was performed, completing the work, analysis of data from tensile test, hardness and fatigue together with the interpretation of images of optical microscopy and scanning electron was taken. The data indicated the high mechanical strength of the alloy, along with its microstructure indicating elongated grains and high surface contour, which shows such resistance by hindering the movement of dislocations. The grooves are clearly shown in the MEV images as well as the classic with increased fatigue loading and subsequent reduction of the number of cycles to rupture behavior shown in the graphs. Therefore we observed the optimal behavior is supported by the league when subjected to fatigue loadings

Recuperação de turbinas hidráulicas danificadas por erosão cavitacional por soldagem com aço inoxidável/cobalto

Pós-graduação em Engenharia Mecânica - FEIS