Induction heating is one of the efficient and modern technique for heating raw materials for hot forging process. The induction heating furnaces use electro-magnetic field to transfer energy to the metal workpiece and heat is generated inside the material. The magnetic field can be provided by using induction coil. The power supplied to induction coil, the moving speed of the billet that is called conveyor speed and the coil box hole diameter are the factors affecting the resultant temperature of the heated billet. In this study, AISI 1045 type steel billets with a diameter of &Oslash / 30 mm and length of 100 mm have been heated in a particular induction heater. During heating, effects of different levels of power, conveyor speed and the coil boxes with different hole diameters are investigated. The 125 KW 3000 Hz induction heater which is available in METU-BILTIR Research and Application Center Forging Laboratory is used in experiments. The heating experiments are designed according to 23 Factorial Design of Experiment Method. Multiple linear regression technique is used to derive a mathematical formula to predict the temperature of the heated billet. A good correlation between the measured temperatures that are the results of different sets of induction heating parameters and the predicted temperatures that are calculated by using temperature prediction formula has been observed.

Forging operation is one of the most commonly used manufacturing techniques in defense industry. The products of forging operation have higher material strength when comparing to traditional manufacturing operations. Especially, for the mass production, it is a beneficial method considering metal and cost saving. The commonly used part named Fin Connector Rod in defense industry requires high material strength due to working conditions. In this thesis, manufacturing of this part by hot forging operation is accomplished after analyzing by using the finite element method. Two alternative forging processes are compared and the applicable alternative method is selected by using a finite element program. Dies are designed for applied processes. The stress distribution and the current temperature variation within the parts analyzed to evaluate the results. The fin connector rod is manufactured according to the results of the finite element analysis. It has been observed that, manufacturing of the fin connector rod by hot forging is succeeded and the waste material and cost is reduced when compared to the machining operation which is being used currently.

Sammandrag Detta examensarbete utförs i samarbete med företaget Componenta Wirsbo AB. Componenta smider detaljer till den tunga fordonsindustrin. Företaget använder sig av sänksmide där materialet formas genom slag från två rörliga verktyg. Smitt material har mycket goda hållfasthets egenskaper samt en mycket homogen struktur. Företaget har som miljömål att minska sin uppvärmningsenergi med 5 %. Componenta arbetar även med ett Leanprojekt som ska leda till en mer kontinuerlig produktion. Det föreslagna värmeåtervinningssystemet kommer även att avsevärt korta avkylningstiden för detaljerna och på så sätt bidra till en mer störningsfri produktion. Detta projekt går ut på att dimensionera en anläggning för värmeåtervinning av kylvattnet från de färdigsmidda detaljerna. Det uppvärmda vattnet kan sedan användas till att värma tappvarmvatten och lokaluppvärmning. För dimensionering av anläggningen genomfördes praktiska test. I dessa test nedsänktes korgar med de smidda detaljerna i vatten och temperaturändringen på detaljerna och vattnet uppmättes. Resultatet av testerna visade att det går att utvinna ca 65 kWh energi ur varje korg med detaljer. Med värmeåtervinning av detaljerna från den mekaniska pressen kan i stort sett endast företagets varmvattenbehov täckas. Om hela produktionen värmeåtervinns kan utöver tappvarmvattenbehovet, ca 50 % av lokaluppvärmningsbehovet tillgodoses. De praktiska testerna visade att korgarna behöver ca 4 - 6 minuter i vattenbadet för att uppnå önskad avkylning. Det beräknade massflödet som pump och värmeväxlare dimensionerats efter är 2 - 9 kg/s. Återbetalningstiden för den investering som behövs för att bygga systemet har beräknats. Om detaljerna från den mekaniska pressen värmeåtervinns återbetalar sig systemet på ca 20 månader. Värmeåtervinning från hela produktionen resulterar i en återbetalningstid på ca 7 månader. / Abstract This diploma work is performed in cooperation with Componenta Wirsbo AB. Componenta are a company specialized in forging parts for the vehicle industry. The company uses drop forging where the material is moulded through hammering by two separated tools. Forged material has very good tensile properties and a very homogenous structure. The environmental goal for the company is to reduce their heating energy with 5%. Componenta are also involved in a Lean project to obtain a more continuous production. The suggested heat recycling system will also shorten the cooling time for the products and thereby contribute to a more non-stop production. The goal of this diploma work is to dimension a system for heat recycling of the cooling water from the forged details. The heated water can then be used for hot water and heating. For dimensioning the system practically testing was performed. In these test's baskets with forged details was dipped in water and the temperature changes on the details and the water was measured. The results from these testes showed that it is possible to extract approximately 65 kWh of energy from each basket. With heat recycling of the details from the mechanical press it is possible to cover the total need of hot water for the company. If the Componenta decides to heat recycle the total production it is possible to cover the hot water need and about 50 % of the heating. The practical testing showed that the baskets needed about 4 – 6 minutes in the water to obtain the desired cooling effect. The pump and the heat exchanger are dimensioned for a flow of 2-9 kg/s. The payoff time for this investment has been calculated. If the company heat recycles the details from the mechanical press the payoff time will be approximately 20 months. Heat recycling of the whole productions will reduce the payoff time too approximately 7 months.

Die steigende Bedeutung des Leichtbaus in der modernen Fahrzeugtechnik stellt stetig neue technologische Herausforderungen an die Hersteller. Dabei rückt die Entwicklung neuer energetisch effizienter Herstellungsverfahren sowie geeigneter Werkstoffe immer weiter in den Vordergrund. In der vorliegenden Arbeit wird die Entwicklung eines zukunftsorientierten kombinierten Gieß-Umformverfahrens zur Herstellung hochfester Aluminiumbauteile, z.B. für die Automobilindustrie, vorangetrieben. Die Anwendung aushärtbarer Aluminiumlegierungen, insbesondere mit höheren Siliziumgehalten, wird betrachtet. Der Schwerpunkt der Arbeit liegt in der Ermittlung und Begründung günstiger Prozessbedingungen für einzelne Prozessschritte von Aluminiumbauteilen (Gießen, Umformen, Warm-, bzw. Kaltauslagern) im Zusammenhang mit dem Siliziumgehalt der Legierung. Die Übertragung der gewonnenen Erkenntnisse auf die Verhältnisse des kombinierten Gieß-Umformverfahrens in einen industrienahen Maß-stab stellte ein weiteres Ziel der Arbeit dar.

Inconel 738, which is a nickel base superalloy used for hot section components of aircraft and industrial turbines is difficult to fabricate and repair by fusion welding due to its susceptibility to heat affected zone (HAZ) intergranular cracking. Crack-free joining of the difficult-to-weld alloy is currently achieved by using linear friction welding (LFW). Nevertheless, oxidation along the joint during LFW is a major problem. Information about the effect of process parameters on the microstructural evolution of linear friction welded nickel base alloys is very limited. In this work, the effect of forging pressure on the microstructure of linear friction welded Inconel 738 was studied. The results as elucidated in this work showed that increased forging pressure caused strain-induced rapid solidification of metastable liquid, which resulted in complete elimination of deleterious liquid phase oxides in bonded material contrasting the generally accepted view that assumes extrusion of solid state oxides during LFW.

Inconel 738, which is a nickel base superalloy used for hot section components of aircraft and industrial turbines is difficult to fabricate and repair by fusion welding due to its susceptibility to heat affected zone (HAZ) intergranular cracking. Crack-free joining of the difficult-to-weld alloy is currently achieved by using linear friction welding (LFW). Nevertheless, oxidation along the joint during LFW is a major problem. Information about the effect of process parameters on the microstructural evolution of linear friction welded nickel base alloys is very limited. In this work, the effect of forging pressure on the microstructure of linear friction welded Inconel 738 was studied. The results as elucidated in this work showed that increased forging pressure caused strain-induced rapid solidification of metastable liquid, which resulted in complete elimination of deleterious liquid phase oxides in bonded material contrasting the generally accepted view that assumes extrusion of solid state oxides during LFW.

Producing axi-symmetrical parts with holes from tubular stock by tube upsetting is a frequently used technique in industry. There are basically four types of tube upsetting process / external, internal, simultaneous internal and external upsetting, and expanding of tube. In general, tubular parts require more than one upsetting stage. In industry, generally trial-error methods, which require lots of time and effort depending on experience, are used for the design of stages. Wrong design causes failures during production. On the other hand, the problems, which are likely to be encountered in manufacturing, can be observed and solved in the design stage by using finite element analysis. In this study, the finite element analyses of external, internal, simultaneous internal and external tube upsetting, and tube expanding processes have been realized. During the analyses, the part and the die geometries at the intermediate stages, which have been designed according to the proposed procedures, have been used. The stress and strain distributions and die filling actions have been observed during the process. The process design and die geometries have been evaluated according to the finite element results. It has been seen that the recommended procedures generally generate acceptable designs. In some cases, it has been noted that minor modifications may be required on the design.

São realizados estudos termodinâmicos de nitretos, carbonetos e carbonitretos dos microelementos V, Nb, Al e Ti, utilizando bancos de dados computacionais do programa FactSage, com finalidade de verificar seus potenciais como inibidores do crescimento do grão na faixa de temperatura do processo de forjamento a quente dos aços. Um procedimento para verificação da solubilidade dos compostos dos microelementos por meio do FactSage foi desenvolvido e foram estudadas situações mais complexas e menos abordadas na literatura, tais como o efeito combinado de dois microelementos no aço e o estudo do comportamento dos carbonitretos em altas temperaturas com variantes do porcentual de carbono e nitrogênio. Os estudos demonstraram que os nitretos com presença de titânio possuem elevada estabilidade em altas temperaturas e, por isso, são potencialmente muito efetivos no controle do crescimento do grão. Alguns carbonetos com presença de nióbio apresentam também uma boa estabilidade em altas temperaturas, assim como os carbonitretos desses dois elementos. Foi verificada uma boa correlação dos produtos de solubilidade obtidos tanto por métodos experimentais como por cálculos termodinâmicos apresentados pela literatura, bem como a valiosa contribuição do software para estudos de precipitação e dissolução de carbonetos, nitretos e carbonitretos na austenita, permitindo auxiliar na seleção de aços e/ou modificação da composição de aços convencionais por meio da adição de microelementos juntamente com uma escolha apropriada de porcentuais de nitrogênio e/ou carbono, quando se busca controlar o crescimento do grão em altas temperaturas. Os resultados obtidos podem auxiliar de forma indireta nos estudos de eliminação de tratamentos térmicos convencionais, seja pelo uso de aços microligados com resfriamento controlado, seja pelo uso de aços convencionais de baixa liga temperados logo após forjamento, permitindo, assim, uma redução dos custos globais das peças. Além dessas considerações, os resultados apresentados e a técnica desenvolvida podem também ser úteis em outras áreas em que seja importante o controle do crescimento do grão, tais como laminação a quente e cementação em alta temperatura. / Thermodynamics studies of nitrides, carbides and carbonitrides of the micro elements V, Nb, Al and Ti were performed using the FactSage program databases, in order to verify their potential for grain growth inhibition in a range of temperatures of hot forged steels. A procedure to verify the solubility of compounds of the micro elements was developed by means of FactSage, and it was studied complex states less discussed in literature, such as the combined effect of two micro elements in steel and the behavior of carbonitrides at high temperatures, varying carbon and nitrogen contents. The studies demonstrate that the nitrides with Titanium have high stability in austenite at elevated temperatures: therefore they are potentially highly effective in grain size control. Carbides with Niobium also present effective stability at high temperatures, as well as the carbonitrides of these two elements. A good correlation was verified between the solubility product obtained either by experimental methods, or by thermodynamics calculation presented by literature. Also, a valuable contribution is made by the software in the studies of precipitation and dissolution of nitrides, carbides and carbonitrides in austenite; thus aiding the selection of steels, and/or modification of the chemical composition of standardized steels, by means of adding micro elements; and providing a suitable choice of carbon and nitrogen content when one seeks to control the grain growth at elevated temperatures. Such results can help indirectly in the studies eliminating conventional heat treatment methods, by using micro alloyed steels with controlled cooling and low alloy steels quenched after forging, with overall reducing costs. Besides these considerations, the results presented and the developed procedure can be useful in other areas where grain growth is an important factor, such as in hot rolling and carburizing at high temperature.

São realizados estudos termodinâmicos de nitretos, carbonetos e carbonitretos dos microelementos V, Nb, Al e Ti, utilizando bancos de dados computacionais do programa FactSage, com finalidade de verificar seus potenciais como inibidores do crescimento do grão na faixa de temperatura do processo de forjamento a quente dos aços. Um procedimento para verificação da solubilidade dos compostos dos microelementos por meio do FactSage foi desenvolvido e foram estudadas situações mais complexas e menos abordadas na literatura, tais como o efeito combinado de dois microelementos no aço e o estudo do comportamento dos carbonitretos em altas temperaturas com variantes do porcentual de carbono e nitrogênio. Os estudos demonstraram que os nitretos com presença de titânio possuem elevada estabilidade em altas temperaturas e, por isso, são potencialmente muito efetivos no controle do crescimento do grão. Alguns carbonetos com presença de nióbio apresentam também uma boa estabilidade em altas temperaturas, assim como os carbonitretos desses dois elementos. Foi verificada uma boa correlação dos produtos de solubilidade obtidos tanto por métodos experimentais como por cálculos termodinâmicos apresentados pela literatura, bem como a valiosa contribuição do software para estudos de precipitação e dissolução de carbonetos, nitretos e carbonitretos na austenita, permitindo auxiliar na seleção de aços e/ou modificação da composição de aços convencionais por meio da adição de microelementos juntamente com uma escolha apropriada de porcentuais de nitrogênio e/ou carbono, quando se busca controlar o crescimento do grão em altas temperaturas. Os resultados obtidos podem auxiliar de forma indireta nos estudos de eliminação de tratamentos térmicos convencionais, seja pelo uso de aços microligados com resfriamento controlado, seja pelo uso de aços convencionais de baixa liga temperados logo após forjamento, permitindo, assim, uma redução dos custos globais das peças. Além dessas considerações, os resultados apresentados e a técnica desenvolvida podem também ser úteis em outras áreas em que seja importante o controle do crescimento do grão, tais como laminação a quente e cementação em alta temperatura. / Thermodynamics studies of nitrides, carbides and carbonitrides of the micro elements V, Nb, Al and Ti were performed using the FactSage program databases, in order to verify their potential for grain growth inhibition in a range of temperatures of hot forged steels. A procedure to verify the solubility of compounds of the micro elements was developed by means of FactSage, and it was studied complex states less discussed in literature, such as the combined effect of two micro elements in steel and the behavior of carbonitrides at high temperatures, varying carbon and nitrogen contents. The studies demonstrate that the nitrides with Titanium have high stability in austenite at elevated temperatures: therefore they are potentially highly effective in grain size control. Carbides with Niobium also present effective stability at high temperatures, as well as the carbonitrides of these two elements. A good correlation was verified between the solubility product obtained either by experimental methods, or by thermodynamics calculation presented by literature. Also, a valuable contribution is made by the software in the studies of precipitation and dissolution of nitrides, carbides and carbonitrides in austenite; thus aiding the selection of steels, and/or modification of the chemical composition of standardized steels, by means of adding micro elements; and providing a suitable choice of carbon and nitrogen content when one seeks to control the grain growth at elevated temperatures. Such results can help indirectly in the studies eliminating conventional heat treatment methods, by using micro alloyed steels with controlled cooling and low alloy steels quenched after forging, with overall reducing costs. Besides these considerations, the results presented and the developed procedure can be useful in other areas where grain growth is an important factor, such as in hot rolling and carburizing at high temperature.

São realizados estudos termodinâmicos de nitretos, carbonetos e carbonitretos dos microelementos V, Nb, Al e Ti, utilizando bancos de dados computacionais do programa FactSage, com finalidade de verificar seus potenciais como inibidores do crescimento do grão na faixa de temperatura do processo de forjamento a quente dos aços. Um procedimento para verificação da solubilidade dos compostos dos microelementos por meio do FactSage foi desenvolvido e foram estudadas situações mais complexas e menos abordadas na literatura, tais como o efeito combinado de dois microelementos no aço e o estudo do comportamento dos carbonitretos em altas temperaturas com variantes do porcentual de carbono e nitrogênio. Os estudos demonstraram que os nitretos com presença de titânio possuem elevada estabilidade em altas temperaturas e, por isso, são potencialmente muito efetivos no controle do crescimento do grão. Alguns carbonetos com presença de nióbio apresentam também uma boa estabilidade em altas temperaturas, assim como os carbonitretos desses dois elementos. Foi verificada uma boa correlação dos produtos de solubilidade obtidos tanto por métodos experimentais como por cálculos termodinâmicos apresentados pela literatura, bem como a valiosa contribuição do software para estudos de precipitação e dissolução de carbonetos, nitretos e carbonitretos na austenita, permitindo auxiliar na seleção de aços e/ou modificação da composição de aços convencionais por meio da adição de microelementos juntamente com uma escolha apropriada de porcentuais de nitrogênio e/ou carbono, quando se busca controlar o crescimento do grão em altas temperaturas. Os resultados obtidos podem auxiliar de forma indireta nos estudos de eliminação de tratamentos térmicos convencionais, seja pelo uso de aços microligados com resfriamento controlado, seja pelo uso de aços convencionais de baixa liga temperados logo após forjamento, permitindo, assim, uma redução dos custos globais das peças. Além dessas considerações, os resultados apresentados e a técnica desenvolvida podem também ser úteis em outras áreas em que seja importante o controle do crescimento do grão, tais como laminação a quente e cementação em alta temperatura. / Thermodynamics studies of nitrides, carbides and carbonitrides of the micro elements V, Nb, Al and Ti were performed using the FactSage program databases, in order to verify their potential for grain growth inhibition in a range of temperatures of hot forged steels. A procedure to verify the solubility of compounds of the micro elements was developed by means of FactSage, and it was studied complex states less discussed in literature, such as the combined effect of two micro elements in steel and the behavior of carbonitrides at high temperatures, varying carbon and nitrogen contents. The studies demonstrate that the nitrides with Titanium have high stability in austenite at elevated temperatures: therefore they are potentially highly effective in grain size control. Carbides with Niobium also present effective stability at high temperatures, as well as the carbonitrides of these two elements. A good correlation was verified between the solubility product obtained either by experimental methods, or by thermodynamics calculation presented by literature. Also, a valuable contribution is made by the software in the studies of precipitation and dissolution of nitrides, carbides and carbonitrides in austenite; thus aiding the selection of steels, and/or modification of the chemical composition of standardized steels, by means of adding micro elements; and providing a suitable choice of carbon and nitrogen content when one seeks to control the grain growth at elevated temperatures. Such results can help indirectly in the studies eliminating conventional heat treatment methods, by using micro alloyed steels with controlled cooling and low alloy steels quenched after forging, with overall reducing costs. Besides these considerations, the results presented and the developed procedure can be useful in other areas where grain growth is an important factor, such as in hot rolling and carburizing at high temperature.