Academic literature on the topic 'Hollow forging'

The diploma thesis deals with the technology of production of the body of an artillery shell caliber 155 mm from C60 steel. The part is manufactured in series of 100,000 pieces. Based on a literature study and materials, a technological procedure of drop forging was designed, taking into account the specific shape of the forging. The volume of the starting blank and the forming force were determined. A suitable forming machine was selected based on the magnitude of the forming force. The design of tools for punching operations and reduction diameters of sets of rollers for forging stretching was also performed. In the technical and economic evaluation, the material costs for the production of the entire series were quantified.

Neste trabalho é realizado um estudo teórico-experimental do processo de forjamento a quente em matriz fechada de peças tubulares, denominadas comercialmente por flanges. O material utilizado para fabricação das peças é a liga de alumínio AA 6351. Normalmente, tais peças são forjadas a partir de billets maciços e os furos centrais são, posteriormente, usinados. Desta forma, este trabalho visa o estudo do uso de billets vazados em substituição aos maciços minimizando a perda de material e força necessária para o forjamento que podem ser relativamente significativos dependendo do peso, geometria da peça, e tamanho do lote produzido. O processo de forjamento foi planejado e executado com auxilio de softwares, onde o projeto do ferramental foi realizado em programa de CAD 3D da empresa SolidWorks, e a simulação numérica computacional, aplicada para predizer o comportamento do material no final do forjamento, no programa Simufact. Forming 11.0. Foram analisados, por simulação numérica computacional, dados como a estimativa da força necessária para forjar a peça em estudo, preenchimento da matriz, escoamento do material e as deformações finais. Utilizam-se cálculos analíticos, baseados na Teoria Elementar da Plasticidade (TEP), para estimar a força necessária para o forjamento. Os resultados obtidos experimentalmente validam a utilização de métodos numéricos e analíticos para desenvolvimento de processos de forjamento. Os resultados de força obtidos utilizando o modelo matemático da Teoria Elementar da Plasticidade (TEP) foram os que mais se distanciaram da força real necessária para o forjamento, no caso do billet maciço foi de 2706 kN, enquanto que a força utilizada no experimento foi de 3432 kN e com a utilização do billet vazado a força calculada pela TEP foi de 2579 kN e a real foi de 2451 kN. Já a simulação indica valores necessários de 2432 kN para o billet vazado e 2814 kN para o billet maciço. Conclui-se, então, que com a utilização de billets vazados a força para o forjamento e o material utilizado são inferiores, assim, comprovando sua vantagem em relação ao processo de fabricação convencional.<br>In this paper is done a theoretical-experimental study of the hot forging process in closed die of tubular components, commercially known as flanges. The material used for the manufacture process of the pieces is AA6351. These pieces are usually forged from massive billets and the central holes are subsequently machined. In this way, this paper aims the use of hollow billets instead of the massive ones, minimizing the loss of material and strength used in forging that can be relatively significant depending on the weight, geometry of the piece and size of the batch produced. The forging process was planned and done with the help of software where the tooling project is performed in CAD 3D from Solidworks, and the computer numerical simulation applied to predict the material behavior at the final of the forging process in Simufact Forming 11.0. Data as strength, die filling, material draining and final deformation are analyzed by computer numerical simulation. Analytical calculation, based on the Plasticity Elementary Theory (TEP), are performed in order to estimate the necessary strength for the forging process. The results, experimentally obtained, validate the use of numerical and analytical methods in forging process development. The strength results obtained using the mathematical model of Plasticity Elementary Theory, were the farthest from the real required strength used in forging. As with the massive billet, the strength was 2706 kN while the strength used in the experiment was 3432 kN and using de hollow billet the estimated strength calculated by the TEP was 2579 kN while the real one was 2451 kN. Yet, the simulation indicates required values of 2432 kN for the hollow billet and 2814 kN for the massive billet. We can therefore conclude that when using hollow billets the strength required in forging and the used material are inferior, thus proving its advantage in relation to the conventional manufacture process.

Este trabalho foi desenvolvido como parte das atividades relacionadas ao projeto de cooperação internacional Brasil-Alemanha intitulado "Bulk metal formed parts for power plants" pertencente ao BRAGECRIM (Iniciativa Brasil-Alemanha para Pesquisa Colaborativa em Tecnologia de Manufatura), realizado em parceria entre o Laboratório de Transformação Mecânica (LdTM) da Universidade Federal do Rio Grande do Sul e o Instituto de Conformação Mecânica (IBF) da Universidade Técnica de Aachen (RWTH), Alemanha. Este projeto visa o desenvolvimento do processo de forjamento a quente em matriz aberta para a produção de um eixo vazado para aplicação em aerogeradores de energia, em substituição à eixos maciços usualmente obtidos por fundição, visando aumento de desempenho mecânico e redução de peso da estrutura. Neste trabalho buscou-se analisar, por meio de simulação numérica computacional empregando o método de elementos finitos, diferentes parâmetros de forjamento, de modo a indicar a configuração operacional que se mostra mais adequada para a produção de um eixo vazado para a aplicação pretendida. Para isto, foram realizados cinco experimentos numéricos, avaliando a influência de parâmetros de forjamento na qualidade do produto forjado. Alguns parâmetros analisados foram: a sequência operacional de forjamento, geometrias e combinações de matrizes utilizadas industrialmente, razão de mordida, etc. Para as simulações termomecânicas foi utilizado o software de Elementos Finitos PEP/Larstran acoplado ao módulo de simulação de microestrutura Strucsim. O material utilizado nas simulações foi o aço DIN 42CrMo4 (AISI 4140). Os resultados mostraram que, dentre as diferentes combinações e geometrias de matrizes analisadas, o emprego de um par de matrizes côncavas, aplicando a sequência operacional-A analisada, tende a propiciar um produto de mais alta qualidade, promovendo maior uniformidade de deformação e microestrutura mais homogênea. Também, a razão de mordida influencia diretamente na qualidade do produto, sendo que uma razão de mordida na ordem de 0,6 induz graus de deformação maiores e mais profundos na peça forjada, ao mesmo tempo em que exige maiores cargas de conformação. Comparativos entre resultados da simulação e resultados experimentais de ensaios de compressão a quente de corpos de prova cilíndricos foram realizados para validação do software de simulação numérica. Os resultados experimentais mostraram que o software de simulação numérica pode prever com boa aproximação o fluxo de material e a evolução microestrutural durante o forjamento a quente do aço DIN 42CrMo4.<br>This work was developed as a part of the activities related to the international cooperation project between Brazil and Germany titled "Bulk formed metal parts for power plants" belonging to BRAGECRIM (Brazil-Germany Initiative for Collaborative Research in Manufacturing Technology). This project is in partnership between the Metal Forming Laboratory (LdTM) from the Federal University of Rio Grande do Sul (UFRGS) and the Institute of Metal Forming (IBF), from Technical University of Aachen (RWTH), Germany. The project aims the development of an open die forging process to produce a hollow shaft for application in wind turbines, replacing the solid shafts usually obtained by casting, in order to increase the mechanical performance and providing weight reduction to wind turbines. The present work aimed to analyze different forging parameters, using Finite Element Method, in order to indicate most suitable forging configuration to the production of a hollow shaft. Five numerical experiments were performed, evaluating the influence of various forging parameters on the quality of the forged product, such as the forging sequence, tool geometries and tool combinations and bite ratio. For thermomechanical simulations the Finite Element software PEP/Larstran was used, coupled to the microstructure simulation module Strucsim. The material used for the numerical simulations was the DIN 42CrMo4 steel (AISI 4140). The results showed that, among the different parameters analyzed, the use of concave dies, applying the operational sequence-A, tends to provide a forged with higher quality, promoting uniform strain distribution and homogeneous microstructure. Also, results showed that a bite ratio around 0,6 provides higher and deeper strain degrees, but requires higher forming loads. Hot compression tests using cylindrical specimens were performed to validate the numerical simulation software, including microstructure evolution. Comparison between simulation and experimental results showed that the numerical simulation software can predict with good approximation the material flow and microstructure evolution during hot forging for DIN 42CrMo4 steel.

碩士<br>國立高雄第一科技大學<br>機械與自動化工程研究所<br>100<br>Due to the fact of the global competition and the ECFA impact, Taiwan&apos;&apos;s manufacturing industry is very rival in the efficiency and cost benefit for the new product development. It is the most important to improve the efficiency in the production management and shorten the cycle in the R&D stage for the purpose of the advantage in the pre-market competition. In recent years, the industry generally applied the simulation analysis of finite element method for the forging process to obtain the information between the mold and the forging. As many of the parameters and simulation cycles, the simulations prolong the R&D stage and the products lag behind in the market rival. In this study, we discussed the leading process parameters with the professional engineers by the application of Taguchi method and then selected the orthogonal array and the levels for the minimal simulation times and the best of the combination of parameters. Applying the result into the DEFORM-3D simulation to explore the feasibility to cut down the times and duration for the simulation period. Simulation results show that upper punch dies, location of the main areas of high stress break location consistent with the experimental die. Corrects upper punch break position Radius and the angle, the maximum stress value was revised by the 1720MPa to 1480Mpa, to solve the break of the upper punch position. The experiment results are available for the precision cold forging R&D and production management in the forging industry.

碩士<br>建國科技大學<br>機械工程系暨製造科技研究所<br>101<br>The forging process is a very complex issue. With the advances in computer simulation technology, many researches have been using computer simulation software to improve the forging process. This article applies Simufact software to simulate multistage forging processes of hollow flange. We propose appropriate mold design to improve the quality of the finished product. There are seven stages in the forging process of this paper. After the computer simulation, defects were found in the fourth stage. Because the shortage situation is found in the last stage, we must add enough volume to the workpiece. After re-simulation, it has a good improvement. In this case, a flat-shaped defect with 25mm in length and 1.2mm in thickness exists near the leading edge of the the punch of the third stage. To reduce this defect, we design a chamfer (of 0.5mm or 1mm) at the leading edge of the punch. And 0.5mm chamfered punch is found effective in reducing the thickness and length of defects. Then, we design a draft angle (of 0.5°,1° or 1.5°) on the punch. And the draft angle of 1° is found effective in reducing the length of defects. According to the discussion in this paper, the forging defects of flat shape can be reduced by appropriate chamfer and draft angle of the punch. But we have to study more real cases on the forging process in order to predict the the optimum value of the chamfer and the draft angle.

碩士<br>國立高雄科技大學<br>機械與自動化工程系<br>107<br>The lightweight and precision of locomotive parts has been the development direction of the manufacture of locomotive parts in recent years. The former can reduce energy consumption and meet current environmental claims, while the latter can reduce production costs. Under this demand, in recent years, the manufacture of locomotive drive shafts has been innovated by the hollow cold forging precision forging process. In the past, such shaft-shaped products were forged by the traditional hot burr forging, the material was transversely forged, and the burrs were removed, and then mechanically processed. Due to the lightweight consideration, the middle hole was processed by deep hole drilling. Therefore, the traditional hot forging process, due to the burr design, the material utilization rate is low, about 65%; the forging is rough, the machining volume is large; in addition, the medium hole processing cost is high, and the deeper the hole depth, the processing cost increases. In this study, SCM420H low-alloy steel was selected as the material, and the material was spheroidally annealed to below 78HRB. The feasibility of the five-station mold design was analyzed using DEFORM simulation software, and the mold design of the shaping process and the extrusion hole punch was discussed. And the overall mold design. According to the simulation results, the mold parts are designed and the forging experiment is carried out. The discussion focuses on whether the quality of the mesoporous section and the depth of the mesopores and the fifth pass shaping process can be achieved. When the medium hole forgings are extruded through experiments, materials can be found. The difference in the influence of the annealing process on the mesoporous cross section. When the fourth and fifth processes are to be carried out later, the depth of the punch is deeper due to the deeper the length of the punch. Therefore, from the integrated punch to the vertical inner punch and the outer punch base, the size of the forged piece can be entered into the tolerance and stabilized, and the mold operates smoothly, which proves that the forging process is feasible. This study successfully established The Study on Development of the Application Cold Hollow Forging Process, with the first pass 1.67, the second pass 3.4, the third pass 5.17, the fourth pass 6.9 aspect ratio punch, and the use of materials. The rate saves 16% of the material, and successfully squeezes the hole and material length at the same time, so that each workpiece has less processing cost of deep hole drilling of more than 100 yuan and processing time can save 100 seconds, for production efficiency and cost.

碩士<br>國立臺灣科技大學<br>機械工程系<br>91<br>Abstract During the processing of forging formation, the friction of the contact face arising between forging tool and molding has always been a topic for discussion. This study puts focus on how to decide the change of friction coefficient during the processing of forging formation. It mainly applies the Project Report of National Science Council [31]: “the inverse model of the study by using matrix to indicate the inverse metallic heat elastic deformed finite element model of the linear square root difference.” The loading history acquired from forging experiment is used as a base, so as to inverse calculate the change of the friction coefficient on the contact face between material and molding, and by means of this inverse calculative structure, investigation is further proceeded towards the hollow material of various geometrical sizes and solid protruding forging. The simulative shapes obtained by two friction coefficient values, that is, one by means of fixed friction coefficient, and the other by fluctuating friction coefficient value obtained from inverse calculation, are taken to compare with the shape acquired by the experiment, revealing that the shape corresponding to the fluctuating friction coefficient acquired by inverse calculative model looks comparatively similar to the shape obtained by experiment. This result verifies the accuracy of the study proposed herein. During the research processing, through the simulative calculation of the hollow materials of various geometrical sizes, it is known that the change of friction coefficient is closely related to the geometrical sizes of the materials. Experiments are conducted towards two hollow materials having the same external diameter. By inverse calculating the hollow round tube having an internal diameter of 30mm, when the downward pressing volume is 29.36%, then its friction coefficient value is . Under the same forging experiment condition, and again using the same inverse calculation procedure and downward pressing volume of 29.36%, the friction coefficient of hollow round tube having an internal diameter of 45mm is . This indicates that when the hollow tools having the same external diameter but different thickness, their corresponding friction coefficient values would change accordingly. The thicker the ring, the larger the friction coefficient would be. Besides, from the equation obtained herein by inverse calculating the relationship between friction coefficient and downward pressing volume of the solid protruding forging, a friction coefficient value having a higher downward pressing volume can be predicted, which is then substituted into the elastic deformed forging model of this study and subsequently acquires the prediction of a protruding shape having a higher downward pressing volume. The result of this study is referential to control the accuracy of the sizes of the shapes during the intensive forging formation processing.