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The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
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Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
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Prediction and Reduction of Die Soldering.Hogan, Patrick Alan 30 April 2008 (has links)
Die Soldering occurs in aluminum permanent mold casting when the cast metal bonds with the die surface and remains stuck upon ejection of the part. Eventually, this layer builds up and production must be stopped for cleaning. It was estimated in a Contech squeeze casting plant in Pierceton, IN, that 1.5% of variable overhead can be directly attributed to die soldering. Previous work at WPI has focused on developing the mechanism of how soldering occurs. This work focuses on how that knowledge can be applied in an industrial setting. The work has focused on 4 major areas: (1) Using MAGMAsoft to predict die soldering, (2) Using surface metrology to measure die soldering, (3) Documenting the total process effects of using strontium modified casting alloys. The work has resulted in: (1) Guidelines for using MAGMAsoft to predict die soldering. The results can be incorporated into the existing MAGMA die soldering module, but provide more accurate time and temperature criteria. (2) The results of the study prove that measurement of the surface of the cast part itself can be used as a method for quantifying die soldering. (3) The total process effects of Sr-modification are reported, along with suggestions for immediate use of Sr-modification at the Pierceton, IN casting plant and guidelines for using Strontium in the future.
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The Effect of Mechanical Mold Vibration On the Characteristics of Aluminum AlloysDeshpande, Jayesh U 21 September 2006 (has links)
"Aluminum-Silicon and Aluminum-Copper alloys are important non-ferrous casting alloys. Different methods have been applied to improve their casting characteristics, their microstructure and consequently, their mechanical properties. Application of mechanical vibrations to the mold during solidification of the alloy is one of these methods. In this study, the effect of controlled mechanical vibrations on the dendrite coherency point, the hot tearing tendency, and the microstructure of B206, B390, and binary Al-7%Si alloys was evaluated. The dendrite coherency point was determined using the two-thermocouple method. The hot tearing tendency was evaluated using the crack susceptibility criterion (CSCb) and by means of measurements using a specially designed ring mold. Microstructure characterization was performed using optical and scanning electron microscopy coupled with image analysis. It was found that mechanical vibrations refine the microstructure of the alloys; and, in the case of B390 alloy, it resulted in significant improvement in the distribution of the primary silicon particles. In the case of B206 and Al-7%Si alloys, where aluminum is the primary phase, mechanical vibrations caused the dendrite coherency point to shift towards lower temperature, i.e., towards higher fraction solid. This shift, together with the refinement of the grain structure, manifested itself in significant reduction in the incidence of hot tearing in B206 castings. "
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Materials cleanliness assessment in rheocasting : An investigation in the melt quality in aluminum alloy castingHellberg, Gustav January 2022 (has links)
The use of aluminum is a key factor in creating an Eco-friendlier automotive industry. The material has good properties and the ability to reuse the material. The requirement on the material in this industry is very high, due to the exposed working environments. The usage of aluminum will reduce the vehicle’s weight, which in turn will reduce emissions. Aluminum casting is not free from obstacles. The properties can be altered with different casting methods and the design of the casting to a great extent. This master will focus on how the melt quality will have an impact on the material properties and how it is changed during the process. To fully understand what happens to the melt during the casting process, samples are received at different stages for further investigation. Different data is collected to be able to analyze what happens during the process. A quality measurement called the Quality index is used to determine the change in the quality in the different stages. With data from bifilm and density index, conclusions can be made on how and where the impurities are entering the melt and their effect. A conclusion is made that the degassing harms the quality of the melt.
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Evolution im Aluminium-Guss von Fahrwerk-KomponentenBeganovic, Thomas 23 December 2016 (has links) (PDF)
Werkstoff- und Prozessgrenzen beschränken unter Beachtung ökonomischer und ökologischer Aspekte den Leichtbau gegossener Fahrwerk-Komponenten aus Al-Si-Legierungen. Zunächst werden Bauteilgewicht und Wärmebehandlungsprozess als beeinflussbare Hauptbeitragsleister für Emissionen im Herstellprozess identifiziert. Zu deren Verringerung werden abhängig von der Belastungsart mögliche Mindestwandstärken abgeleitet, die für den Kokillenguss um 35 % reduziert werden. Dies gelingt durch Einsatz neuartiger, das Formfüllverhalten verbessernder Oberflächenstrukturierungen von Gießwerkzeugen bei Einhaltung von Konstruktionsregeln. Die Gesamtprozesszeit der Wärmebehandlung kann bei gleichbleibenden mechanischen Eigenschaften um 40 % verkürzt werden. Dabei erfolgt die Charakterisierung des Werkstoff- und Bauteilverhaltens unter dynamischer Belastung bei Parametervariation, da keine Korrelation zu den statischen mechanischen Kennwerten vorliegt.
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Evolution im Aluminium-Guss von Fahrwerk-KomponentenBeganovic, Thomas 12 September 2016 (has links)
Werkstoff- und Prozessgrenzen beschränken unter Beachtung ökonomischer und ökologischer Aspekte den Leichtbau gegossener Fahrwerk-Komponenten aus Al-Si-Legierungen. Zunächst werden Bauteilgewicht und Wärmebehandlungsprozess als beeinflussbare Hauptbeitragsleister für Emissionen im Herstellprozess identifiziert. Zu deren Verringerung werden abhängig von der Belastungsart mögliche Mindestwandstärken abgeleitet, die für den Kokillenguss um 35 % reduziert werden. Dies gelingt durch Einsatz neuartiger, das Formfüllverhalten verbessernder Oberflächenstrukturierungen von Gießwerkzeugen bei Einhaltung von Konstruktionsregeln. Die Gesamtprozesszeit der Wärmebehandlung kann bei gleichbleibenden mechanischen Eigenschaften um 40 % verkürzt werden. Dabei erfolgt die Charakterisierung des Werkstoff- und Bauteilverhaltens unter dynamischer Belastung bei Parametervariation, da keine Korrelation zu den statischen mechanischen Kennwerten vorliegt.
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