The purpose of this thesis is to provide an overview of the methods used in the appended papers, in order to consider heterogeneous material properties in finite element simulations by using process simulations as input. The work deals with both injection moulded and cast components, and focuses on process-induced local material variations and their effect on component performance. The influence of heterogeneous properties originating from the casting process as well as some other common simplifications, which are made in finite element analyses, are evaluated for a cast iron component. It is found that commonly neglected properties such as compressive strength, residual stresses, temperature dependency and heterogeneous properties have a non-trivial and potentially large influence on the simulation results. Lastly, a computational method for fibre reinforced plastics is presented. The methodology enables designers to consider the non-linear anisotropic properties of fibre-reinforced polymers, due to the flow-induced fibre orientation predicted by injection moulding simulations. The method allows material data assignment in each integration-point of the structural mesh. The method is demonstrated to capture the behaviour of the full range of fibre orientations simultaneously with good accuracy. / Syftet med denna avhandling är att översiktligt beskriva de metoder som används i de bifogade artiklarna. Dessa metoder möjliggör beaktandet av heterogena materialegenskaper vid hållfasthetsberäkningar med hjälp av finita element metoden (FEM), genom att först simulera tillverkningsprocessen. Arbetet behandlar både formsprutade och gjutna komponenter, och fokuserar på process-inducerade lokala materialvariationer, samt hur dessa påverkar komponenters prestanda. En gjutjärnskomponent har studerats med syftet att undersöka inverkan av heterogena materialegenskaper från gjutprocessen, samt några andra vanligt förekommande förenklingar som görs i industriella hållfasthetsanalyser. Genom att försumma materialets kompressionsbeteende, eventuella restspänningar ifrån gjutprocessen, temperaturberoende, samt den heterogena fördelningen av materialegenskaper ifrån tillverkningsprocessen introduceras icke-triviala och potentiellt stora fel i simuleringsresultaten. Slutligen presenteras en beräkningsmetod för fiberförstärkta formsprutade plaster. Initiala simuleringar av formsprutningsprocessen används för att prediktera den lokala fiberorienteringen, vilken används för att möjliggöra hållfasthetsberäkningar som tar hänsyn till det olinjära och anisotropa materialbeteendet hos formsprutade fiberförstärkta komponenter. Metoden möjliggör att materialdata kan appliceras i varje integrationspunkt i beräkningsnätet, och har utvärderats genom att demonstrera ett korrekt materialbeteende för flera fiberorienteringar samtidigt, med god noggrannhet.

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An investigation has been carried out to determine the factors controlling the wear characteristics of disc poppet valves in reciprocating slurry pumps used in the transportation of quartzite slurries. A laboratory test rig has been designed and built which closely simulates the operating conditions experienced by slurry pump valves. Experiments have been conducted to determine the effect of the design parameters, namely - slurry constitution, valve closure velocity and valve angle, on the wear resistance of a low alloy steel, as a function of its mechanical properties. It has been shown that the wear of the valves is a sensitive function of the operating parameters. Significant improvements in the life of the valves can be achieved through increasing material hardness, reducing valve closure velocity, slurry density and valve angle. A detailed study has been made of the mechanisms contributing to valve wear. It has been established that both percussive impact and three body abrasion wear mechanisms predominate. The influence of each mechanism has been shown to be a function of the slurry constitution and the material hardness.

The zeolite ZSM-5 is well-known for its unique intersecting channel system. This channel system has a great bearing on the shape-selective properties and the long life-times of ZSM-5. In this study, ZSM-5 was modified in various ways to eliminate the external acidity of the catalyst to further improve these properties, and the success and effects of these modifications were investigated primarily using temperature programmed desorption techniques. The internal surface of ZSM-5, a medium pore zeolite, plays a major role in the shape selective properties of this catalyst, due to the diffusional restrictions imposed by the channel system on bulky molecules. Even though the number of acid sites on the external surface is small compared to the total number of acid sites, these easily accessible and non-shape selective acid sites may provide a high turnover rate for non-shape selective reactions. Furthermore, the main cause of deactivation of ZSM-5 is thought to be the formation of polyaromatic molecules on the external surface, which block access to the channels of the catalyst.

Bibliography: pages 96-102. / During the annealing treatment in the production of dual phase steels, partitfoning of alloying elements can occur depending on competitive solubility in the ferrite and austenite for the specific partitioning species. An investigation of the partitioning of substitutional elements was considered paramount in understanding certain anomalies that had been identified by previous researchers in various studies of a dualphase 12% Chromium steel, designated 3CR12. These anomalies concerned observed increases in bulk hardness that could not be attributed to changes in the volume fraction of martensite produced after exposure to a range of temperatures within the dual phase field. Subsequent experiments revealed an unexpected increase in the microhardness of the martensite phase prOduced by heat treatment in the temperature range of interest. In this thesis conventional analytical measurements using Energy dispersive X-ray analysis facilities attached to a Scanning Electron microscope have been utilised to determine the compositions of the two phases in the alloy. A range of temperatures in the dual phase region have been investigated at holding durations of 1, 4 and 20 hours. It was found that partitioning of substitutional elements was occurring, however no changes were observed as a function of holding time. Further empirical data was obtained using dilatometric methods. This strongly suggested that interstitial concentrations were increasing as a function of annealing time and clarified the anomalies observed during previous studies on 3CR12. Further study includes that of substitutional element partitioning in the prior states of the commercially produced hot-rolled and annealed 3CR12 alloy. These include the as cast slab and the hot-rolled slab, as well as the final hot-rolled and annealed slab. Segregation was found to occur in the as cast slab. Subsequent investigation showed the presence of δ-ferrite in the final processing stages of the hot-rolled and annealed product.

In order to determine storage life for aluminum alloys it is essential to have a good knowledge on the accelerated aging behavior and the mechanical properties that are affected. The selected aluminum alloys are AA2017, AA6082, AA7075 and the study has been focused on their impact toughness and hardness relation to aging beyond peak conditions. To be able to plot the mechanical properties versus aging time and temperature, Differential Scanning Calorimetric runs have been the key to obtain supporting activation energies for a specific transformation. The activation energies have been calculated according to the Kissinger method, plotted in Matlab. Arrhenius correlation has also been applied to predict the natural aging time for long time storage in 30 degrees Celsius. It could be concluded that the results from the mechanical test series show that the constructed Arrhenius 3D method did not meet the expectations to extrapolate constant activation energies down to storage life condition. Scanning electron microscopy together with light optical microscopy analyses show how important it is to apply notches in proper test specimen directions and how precipitates are grown, as it will affect impact toughness and hardness. An ending discussion is held to explain how mechanical testing progressed and how other external issues affected the master thesis operations.

The use of ceramic material as refractories in the manufacturing industry is a common practice worldwide. During usage, for example in the production of steel, these materials do experience severe working conditions including high temperatures, low pressures and corrosive environments. This results in lowered service lives and high consumptions of these materials. This, in turn, affects the productivity of the whole steel plant and thereby the cost. In order to investigate how the service life can be improved, studies have been carried out for refractories used in the inner lining of the steel ladles. More specifically, from the slag zone, where the corrosion is most severe. By combining thermodynamic simulations, plant trails and post-mortem studies of the refractories after service, vital information about the behaviour of the slagline refractories during steel refining and the causes of the accelerated wear in this ladle area has been achieved. The results from these studies show that the wear of the slagline refractories of the ladle is initiated at the preheating station, through reduction-oxidation reactions. The degree of the decarburization process is mostly dependent on the preheating fuel or the environment. For refractories without antioxidants, refractory decarburization is slower when coal gas is used in ladle preheating than when a mixture of oil and air is used. In addition, ladle preheating of the refractories without antioxidants leads to direct wear of the slagline refractories. This is due to the total loss of the matrix strength, which results in a sand-like product. Thermal chemical changes that take place in the slagline refractories are due to the MgO-C reaction as well as the formation of liquid phases from impurity oxides. In addition, the decrease in the system pressure during steel refining makes the MgO-C reaction take place at the steel refining temperatures. This reduces the refractory’s resistance to corrosion. This is a serious problem for both the magnesia-carbon and dolomite-carbon refractories. The studies of the reactions between the slagline refractories and the different slag compositions showed that slags rich in iron oxide lead mostly to the oxidation of carbon/graphite in the carbon-containing refractories. This leads to an increased porosity and wettability and therefore an enhanced penetration of slag into the refractory structure. If the slag contains high contents of alumina and or silica (such as the steel refining slag), reactions between the slag components and the dolomite-carbon refractory are promoted. This leads to the formation of low-temperature melting phases such as calcium-aluminates and silicates. The state of these reaction products during steel refining leads to an accelerated wear of the dolomite-carbon refractory. The main products of the reactions between the magnesia-carbon refractory and the steel refining slag are MgAl2O4 spinels, and calcium-aluminates, and silicates. Due to the good refractory properties of MgAl2O4 spinels, the slag corrosion resistance of the magnesiacarbon refractory is promoted. / QC 20101013

<p>QC 20150219</p>

<p>QC 20150305</p>

The increasing demand of light constructed vehicles as well as soaring price of copper metal owing to limited nature resources have been promoting the use of aluminium metal as an alternative conductor of automotive cables. This thesis work is to lay theoretical foundations for further research and development regarding the introduction of new automotive cables i.e. aluminium cables. Current application of automotive aluminium cables in automotive industry as well as failure analysis and evaluation approaches with respect to aluminium cables in automotive settings can serve as a baseline for further research regarding the implementation of aluminium cables in Scania products. Before investigating probable substitutions in terms of automotive cable uses in Scania products as well as the following consequences, historic overview concerning aluminium cables in automotive applications is stated while major challenges and current technical progresses are established, indicating that large-sized aluminium cables such as battery cables have been implemented in some vehicles and the uses of aluminium cables in lower power segments are expected in near future. Due to inferior strength of aluminium conductor as well as its poor contact behaviors while deteriorations by galvanic corrosion, oxidization or tension relaxes, etc, might occur in contact interface, interruptions in aluminium conductor and its termination are challenging the adoption of aluminium cables in present automotive cable harness system. In order to assess performances of aluminium cables in automotive vehicles, necessary evaluations shall be conducted from mechanical, electrical, thermal and chemical aspects.  Attempts have already been made to examine behaviors of aluminium conductor in this thesis work, with results showing that aluminium conductor would behave poorly which is also in agreement with previous studies about failure analysis.