Les alliages Al-Si sont largement utilisés dans l’industrie automobile en fonderie sous pression, en particulier pour la fabrication des blocs moteurs, en raison de leurs bon rapport résistance/ poids et leurs excellentes propriétés mécaniques. Du fait de l’internationalisation de la production, la composition chimique de ces alliages et les paramètres du procédé HPDC peuvent varier d’un pays à l’autre, ils peuvent même varier d’un site de fabrication à l’autre dans le même pays. Or, les conceptions des pièces automobiles sont aujourd’hui de type déterministe et elles sont réalisées sur la base des matériaux et procédés européens, ce qui peut affecter les propriétés de ces pièces dans le cas d’une localisation hors Europe. Ainsi, il est important de pouvoir adapter les conceptions rapidement et à moindre coût en prenant en compte les contraintes matériau/ process locales. Dans cette thèse, nous avons proposé une approche méthodologique permettant de prédire les caractéristiques mécaniques en fonction de la variabilité matériaux/ process en s'appuyant sur une étude expérimentale/ statistique de l’effet de la variabilité des principaux éléments d’alliage (Si, Cu, Mg) et des paramètres procédé (température de la coulée et pression d’injection) sur les propriétés mécaniques des alliages d’Al-Si moulés sous pression. La microstructure et le taux de porosités ont également été évalués. Cette méthodologie a abouti à la construction d’un outil de conception produit permettant de prédire les caractéristiques mécaniques dans le cas du changement de l’un (ou des) paramètres Matériau/ Process. / Secondary Al-Si alloys are widely used in automotive industry for engine blocks because they offer a considerable weight reduction whilst maintaining good mechanical properties. The ever-expanding internationalisation of production, with same stages of production processes spread across a number of countries to produce locally, causes however high variability in the casting products. The chemical composition of the same alloys and the working variables of the unchanged high-pressure die casting process (HPDC) may change for the same casting parts from one country to another, they can even sometimes vary from one manufacturing site to another within the same country. Designing for aluminium automotive components does call today for new deterministic design methods that are often achieved from European material and casting process databases, which can affect the properties of these parts in the case of a location outside Europe. Thus, it is important to adapt the design of die casting parts quickly and inexpensively by taking into account the material and process local constraints. In this work, a methodological approach which permits to predict mechanical properties as a function of material and process variability based on an experimental/ statistical study on the effect of the variability of the primary factors of alloying elements contents (Si, Cu and Mg) and HPDC process parameters (casting temperature and injection pressure) on mechanical properties of die cast aluminium alloys has been proposed. The microstructural features and the porosity level were also investigated and assessed. This approach has resulted in statistical design tool that will allow designers to make changes to the design of their casting and to industrialize them outside Europe.

The aim of this thesis is to determine influence of porosity and shape-factor over mechanical properties, performed on cast samples from Aalen foundry (Germany), that were high pressure die casted from AZ91 D Alloy. Evaluation of these quantities was done using computer software Olympus Five. Measured values were subjected to statistical analysis in order to eliminate gross errors and determine linear dependence between mechanical properties and porosity eventually voids shape factor.

The purpose of this diploma thesis is an evaluation of die-castings porosity, eventually the evaluation of seats with local squeeze in connection with their mechanical and structural properties. The swatches of alloy AISi9Cu3 were taken from the engine block made by Škoda Auto Company, Mladá Boleslav. To the evaluation and the comparison of the results there were used value of porosity with own measure and other student´s thesis of Brno University of technology. Sets of mechanical and structural properties were selected, evaluated and tested by statistical programs.

The aim of this diploma thesis is to analyse the porosity of die - cast cast that were made of the alloy AISi9u3 in iron-foundry Skoda Car Mlada Boleslav. The analysis and the sample comparisons are based on my own measurements and are also connected with previous diploma thesis which deals with that issue and was drawn up at Technical University in Brno. All measurements were statistically tested.

This master thesis will cover the possibility of using directed gassing of Al-Si alloys in a high pressure die casting foundry. As a control gas, rotary degasser with gaseous 20 % H2 in N2 as a medium was used. Castings were casted via high pressure die casting machine. The aim of this research is to compare internal defect such as porosity or shrinkage of a casts made from degassed and control gassed melt.

<p>High pressure die casting is an industrial metal casting process used to manufacture goods for use in many aspects of society. Within this manufacturing process, the tooling is subjected to chemical attack from molten aluminum while also being responsible for heat removal during solidification. The purpose of this study is to develop and test materials that allow the tools to better withstand the chemical attack, and to develop design rules to guide the use of additive manufacturing for improving the heat exchange function of by way of conformal cooling.</p> <p> </p> <p>Within the material studies, a gooseneck with a niobium lining was developed to allow the successful implementation of hot chamber aluminum die casting. In addition, a manufacturing plan is described that will allow the niobium gooseneck design to be easily sourced by die casting companies. The material studies also included dunk testing of several coatings, including a plasma assisted chemical vapor deposition silicon doped diamond like carbon (PACVD Si-DLC). The Si-DLC coating performed the best in the dunk testing as compared to bare and nitrocarburized tool steel, and a number of other coating architectures.</p> <p> </p> Within the study of additively manufactured conformal cooling design, a finite difference model is developed that allows a simulated experiment that produced a number of useful equations that guide the design of die casting tooling. During the development of the models, it was discovered that little is known regarding the friction factors of additively manufactured steel pipes, so a factorial experiment was employed to empirically determine said friction factors. Charts allowing design engineers to quickly determine pressure drops and heat transfer coefficients of conformal cooling designs was produced as well.<br>

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Thesis (M. Tech. (Engineering: Mechanical)) -- Central University of Technology, Free State, 2013 / This research examines the suitability of Additive Manufacturing (AM) for manufacturing dies used in aluminium high pressure die casting. The study was guided by the following objectives: • The reviews of applicable literature sources that outline technical and application aspects of AM in plastic injection moulds and the possibilities of applying it to high pressure casting die. • To introduce AM grown die components in die manufacture. Further, to develop a methodology that will allow industry to apply AM technology to die manufacture. • Revolutionise the way die manufacture is done. The potential for AM technologies is to deliver faster die manufacture turnaround time by requiring a drastically reduced amount of high level machining accuracy. It also reduces the number of complex mechanical material removal operations. Fewer critical steps required by suitable AM technology platforms able to grow fully dense metal components on die casting tools able to produce production runs. • Furthermore, promising competitive advantages are anticipated on savings to be attained on the casting processing side. AM technology allows incorporation of features in a die cavity not possible to machine with current machining approaches and technology. One such example is conformal cooling or heating of die cavities. This approach was successfully used in plastic injection mould cavities resulting in savings on both the part quality as well as the reduction on cycle time required to produce it (LaserCUSING®, 2007). AM technology has evolved to a point where as a medium for fast creation of an object, it has surpassed traditional manufacturing processes allowing for rapidly bridging the gap between ideas to part in hand. The suitability of the AM approach in accelerating the die manufacturing process sometime in the near future cannot be dismissed or ignored. The research showed that there is promise for application of the technology in the not too distant future. In the South African context, the current number and affordability of suitable AM platforms is one of the main stumbling blocks in effecting more widespread applied research aimed at introduction of the technology to die manufacture.

<p>Quality of the castings is affected by several factors which the designer should take into consideration during the product development process. Although residual stress is one of those, it is often not considered in practical computations. Hence residual stresses are one of the forgotten areas in designing of machine parts. This master thesis is focused on the investigation of residual stresses in a high pressure die casted component, with the aim of extending its service life, by taking results from the study as a feedback.</p><p>The investigation of residual stresses was done on a variety of specimens, cast aluminum flywheel, provided by Husqvarna AB. This flywheel is a component in a product of the same company.In evaluating the residual stresses in the part, two tools-simulation and physical measurement were used. Moreover, comparison with these two methods is also done at an area of interest on the flywheel. The simulation was carried out by using MAGMAhpdc-a module for high pressure die casting process, from the commercial software package MAGMAsoft; while for the physical measurements, the hole drilling method was used, a method believed to be less accurate at low stresses areas.</p><p>The findings obtained from this study show that the results from both procedures are close, with small deviations observed, which reveals the reliability of the hole drilling method even when the stress levels are low. It is also found that the compressive residual stresses dominate in the component-a preferred phenomenon with regards to residual stress.</p>