Ovakos induktionslinje i Hällefors består av induktionshärdning följt av induktionsanlöpning.  Släckningen vid härdningen sker med hjälp av duschar. Tidigare har Ovako använt sig av polymermedlet Aqua Tensid som släckningskoncentrat. I samband med användning av Aqua Tensid har kund upplevt förbättring i skärande bearbetning.  Användningen av Aqua Tensid har dock upphört p.g.a. arbetsmiljöproblem. Ovako har istället införskaffat Thermisol, ett annat polymermedel till släckningsprocessen. Detta arbete innehåller en utvärdering av Thermisol i Ovakos produktion då det tidigare inte gjorts. Test har utförts i induktionslinjen med släckning från rent vatten upp till en koncentrationshalt på 8,4% Thermisol. Testerna är utförda på stålsorten Ovako 356D. Från testerna har prov tagits ut och analyserats efter härdning samt efter anlöpning. Stängerna från testen har även följts upp i Ovakos svarvavdelning för att utvärdera om det uppstår skillnad i skärbarhet. De enbart härdade proverna visar på att prover släckta i Thermisol har större benägenhet till självanlöpning vid ytan. De resterande proverna visar inte på någon märkbar skillnad. Uppföljningen i svarv visar inte på någon skillnad i skärbarhet för stålsorten Ovako 356D.

En undersökning av inneslutningsbeteende under tillverkningsprocessen av götgjutet verktygsstål har utförts på Uddeholm i Hagfors. Med hjälp av OES med PDA och SEM med INCA feature undersöktes sammansättningen, antalet, storleken, fördelningen, koncentrationen och formen av inneslutningar före och efter vakuumbehandlingen samt i kokill.   Fyra typer av inneslutningar kunde identifieras i olika skeden i processen. Al2O3-MgO spineller i flytande CaO- Al2O3 lösning, CaO-Al2O3 flytande inneslutning, Al2O3-MgO Spineller och Al2O3-SiO2 i fastform.  Vakuumbehandlingen påverkar typen, formen, storleken och antalet inneslutningar. Den induktiva omrörningen påverkar antalet och storleken av inneslutningarna. Vid avgjutningen utskiljs Al2O3-SiO2 som med stor sannolikhet beror på provtagningen.

O trabalho apresentado aqui visou estudar a implantação de elementos em superfícies metálicas (particularmente cobre) de maneira controlada, investigando-se as alterações que tal implante causou na estrutura da superfície, objetivando uma possível melhoria no comportamento desses metais a serem utilizados como catodos em tochas de plasma ou para várias outras aplicações, tais como em catálise, micro eletrônica, oxidação e corrosão de metais e outros. Filmes finos de cobre policristalino foram implantados com íond (energia de 20KeV até 50KeV; doses da ordem de 10 15íons/cm2) de metais alcalinos (Li, Na, K, Rb e Cs) bem como de O e Cl. Foram realizadas diversas análises de superfície visando determinar as alterações ocorridas no cobre quando da implantação dos íons, tais como: composição de superfície (Auger Electron Spectroscopy, X-ray Photoelectron Spectroscopy), estrutura de superfícies em termos de topografia e do potencial de superfície (Kelvin Probe Force Microscopy), composição volumétrica X-ray Fluorescence, Rutherford Backscattering Spectroscopy e Energy Dispersive X-ray Spectroscopy), concentração de oxigênio (Elastic non-Rutherford Backscattering Spectroscopy) e estrutura cristalina (X-ray Diffraction). Modelos teóricos foram utilizados para se obter uma compreensão melhor das alterações estruturais que ocorrem durante a implantação iônica em uma superfície metálica (Stopping and Range of Ions in Matter e Tight-Binding Linear Muffin-Tin Orbital Atomic Sphere Approximation (Coherent Potential Approximation)). As análises de composição superficial mostraram que as concentrações dos elementos C, N, Cl e S dos substratos de cobre não implantados e implantados foram similares e que a única alteração na composição superficial, causada pelo processo da implantação iônica, foi a introdução dos íons desejados nos filmes de cobre. Observou-se que mesmo as pequenas doses de íons podem causar uma grande diminuição da função de trabalho (2-30%) em relação ao cubro puro; já a implantação de O e Cl gerou um aumento na função de trabalho de 300mV e 900MV, respectivamente. As concentrações detectadas de íons implantados de metais alcalinos podem ser consideradas altas (tendo em vista as doses de implantação relativamente pequenas, da ordem de 10.15ions/cm2) diminuindo rápido na direção do bulk das amostras; esta distribuição se deve provavelmente a um processo de migração de íons na direção da superfície. Os resultados de EBS e KPFM indicam que uma maior dose não necessariamente gera uma concentração maior de íons implantados na primeira camada superficial. Observou-se também que somente uma parte da dose total dos íons é efetivamente implantada, devido ao processo de sputtering, que ocorre durante a implantação iônica. A implantação iônica de diferentes íons alcalinos influencia diferentemente os processos de oxidação das amostras. A principal influência no aumento da oxidação é a estrutura topográfica das amostras; porém, a presença de íons implantados nas superfícies das amostras parece influenciar as etapas iniciais de oxidação, aumentando ou diminuindo a absorção de oxigênio. Para o caso da implantação dos íons de O e Cl, a concentração desses íons parece aumentar com a profundidade até um certo nível, o que, por sua vez, indica que não houve um processo de migração durante a implantação. Isto se deve provavelmente ao fato de que estes íons criam ligações com os elementos de substrato. As alterações da função de trabalho de dois casos distintos de deposição de metais (Ag e Cs) sobre Cu (111), foi estudada com o programa TB-LMTO-ASA (CPA), utilizando-se, nas simulações, valores diferentes para o raio de Wigner-Seitz para esferas vazias (WSES); os resultados das alterações da função de trabalho durante a deposição foram aproximadamente 20% menores em comparação com os valores experimentais da literatura. O efeito de WSES, que é, em princípio, um artefato computacional, sobre o valor da função de trabalho do sistema é normalmente interpretado como uma não confiabilidade dos modelos baseados nos conceitos de ASA. Porém, os resultados obtidos durante este trabalho indicam a existência de uma relação entre WSES e a rigorosidade da superfície; portanto, o sentido físico de esferas vazias pode ser visto como uma medida da rugosidade superficial. / In this work, the controlled implantation of the different elements in the metallic surfaces (particularly copper) was performed, in order to study the changes that the implantation causes on the surface structure, aiming to improve the behaviour of those metals for their use as cathodes in plasma torches or other applications, such as: catalysis, microelectronics, oxidation and corrosion of metals and others. Thin polycrystalline copper films were implanted with ions (energy 20-50keV; doses of order of \'10 POT. 15\' ions/\'cm POT. 2\') of alkaline metals (\'LI\', \'NA\', \'K\', \'RB\', and \'CS\') as well as of \'O\' and \'CL\'. Different surface analyses were performed in order to determine the changes on copper due to the ion implantation, in terms of: surface composition (Auger Electron Spectroscopy, X-ray Photoelectron Spectroscopy), topographic and surface potential structure (Kelvin Probe Force Microscopy), bulk composition (X-ray Fluorescence, Rutherford Backscattering Spectroscopy e Energy Dispersive X-ray Spectroscopy), oxygen concentration (Elastic non-Rutherford Backscattering Spectroscopy) and crystalline structure (X-ray Diffraction). Theoretical models were used to understand better the structural changes which occur on the metallic surface during the ion implantation process (Stopping and Range of Ions in Matter e Tight-Binding Linear Muffin-Tin Orbital Atomic Sphere Approximation (Coherent Potential Approximation)). The surface composition analyses of implanted and non-implanted copper substrates showed similar concentration of \'C\', \'N\', \'CL\' and \'S\' and that the only change in surface concentration, due to the ion implantation process, was the introduction of the desired ions in the surface of copper films. It was observed that even small ion doses can cause relatively large decrease of work function (2-30%) in relation to the pure copper value; the implantation of O and CL caused an increase in work function of 300m V and 900mV, respectively. The detected concentration of implanted alkali metal ions was relatively high (taking into consideration relatively small implantation doses, of the order of \'10 POT. 15\' ions/\'cm POT. 2\'), decreasing fast towards bulk of the samples; this distribution were probably caused by a migration process of implanted ions towards the surface. The EBS and KPFM results indicate that not always the largest dose produces the largest implanted ion concentration in the surface layer. It was also observed that only a part of the total ion dose is effectively implanted, due to the sputtering during the ion implantation process. Implantation of different alkali ions influences the sample oxidation process in a different way. The principal influence in the increase of oxidation is the topographic structure of the samples; however, the presence of the implanted ions on the samples surface seems to influence the initial stages of the oxidation, increasing or decreasing the oxygen adsorption. Of the cases of the O and CL implantation, the concentration of these ions seems to increase with depth, which indicates that there were no migration process involved. This is probably due to the fact that these ions create bonds with the substrate elements. The changes in the work function for two distinct cases of metal (AG and CS) deposition on CU (111) was studied with the computational programme TB-LMTO-ASA (CPA), using, in the simulations, different values for the Wigner-Seitz radius for Empty Spheres (\'WS IND. ES\'); the results on the work function changes during the deposition were approximately 20% lower in comparison with the experimental data from the literature. The effect of \'WS IND. ES\', which is, in principle, a computation artefact, on the work function value of the studied systems is normally interpreted as the non-reliability of the models based on the ASA concepts. However, the results obtained during this work indicate that there is a relation between the \'WS IND. ES\' and the surface roughness; therefore, physical meaning of the empty spheres can be understood as a \"measure\" of surface roughness.

Due to the trend of increasing environmental demands put on civil aviation, manufacturersof commercial aircraft engines meet increased pressure to reduce weight. Modernturbofan engines represent up to almost one tenth of an aircraft's total weight, meaning areduction of engine component weight of just 30 kg is estimated to reduce CO2 emissionsby 400 tonnes over the lifetime of a medium sized commercial aircraft. At the sametime turbine casings are required to fully prevent debris to escape in the event of bladefailure, to prevent further damage to critical systems. For new designs to be approvedthe Federal Aviation Regulations (FAR) states that the containment capability of a suggesteddesign solution must be experimentally established, a process associated with highcosts and long lead times. The industry therefore more frequently relies on numericalsimulations as part of all stages in the design process. For simulations to replace theexpensive experiments in nding the nal optimum design regarding weight and safety,the accuracy of the used models have to be improved.This thesis aims to provide increased accuracy in the numerical predictions by developingexperimental procedures to test material close to the operational conditions of thecontainment structure. This is realised by performing experiments at high-strain ratesand elevated temperatures in a high-velocity tensile testing machine combined with aninduction heater. Sheet specimens of varying geometries are loaded in tension to achievedierent stress states for covering dierent failure modes. Furthermore, high-speed photographyand Digital Image Correlation are utilised to track in-plane deformations. Theresulting local deformations are then used to derive the stress-strain hardening relationand the evolution of the stress state from initial loading up to fracture. The obtaineddata are nally used to calibrate strain rate and thermal dependent plasticity and fracturemodels. To validate the calibrated models so-called reverse impact testing was used,where the resulting force of a material sample impacting an instrumented target wasquantied. The experiment was straightforward to model numerically since the specimenies freely without constraints, thereby avoiding complex boundary conditions.The characterisation method was developed and performed on nickel based Alloy 718.This material is known for its high strength and good corrosion resistance at high temperaturesand is therefore commonly used in hot parts of aircraft engines, such as thecontainment structures of the low-pressure part of the engine turbine. All material fortesting and validation was supplied from one single heat and batch, aged using the sameheat treatment conditions, to ensure consistent mechanical properties. The results fromthe characterisation procedure showed that the plastic ow of Alloy 718 is moderatelystrain rate and temperature dependent while the fracture is clearly stress state dependent.

La motivation principale de cette thèse est d’être capable de prédire précisément la rupture d’une tôle d’aluminium anisotrope avec un chemin de déformation linéaire et non-linéaire. Dans le cas présent, le matériau utilisé est l’AA6016 et le chemin de déformation considéré est traction uniaxiale suivie de pliage jusqu’à rupture. Deux approches sont appliquées et comparées, l’une utilise la plasticité associée (AFR) et l’autre la plasticité non-associée (NAFR). Dans le but d’obtenir une bonne représentation de l’anisotropie en AFR, un critère de plasticité très flexible est utilisé : Yld2004-18p. L’identification des paramètres est faite avec une approche inverse qui consiste à minimiser itérativement l’écart entre les résultats numériques et expérimentaux. Une fois que l’écart arrête d’évoluer (minimum local) ou atteint une valeur prédéterminé e assez faible, l’optimisation s’arrête et les derniers paramètres mis à jour sont enregistrés. En corrélation avec des travaux de recherche plus récents, un modèle NAFR est utilisé pour modéliser l’anisotropie du matériau. Il combine deux critères de plasticité qui sont utilisés pour la surface d’écrouissage et le potentiel plastique. Leurs paramètres sont identifiés grâce aux ratios de contraintes et aux valeurs r obtenues expérimentalement. Concernant la rupture, des modèles découplés macroscopiques sont étudiés : un critère Hosford-Coulomb modifié et un critère basé sur DF2014. Ces deux critères prennent en compte les trois invariants du tenseur des contraintes pour prédire la déformation équivalente à rupture mais sont identifiés avec différentes méthodes pour prendre en compte l’anisotropie de la rupture. Enfin, des résultats sur des instabilités plastiques obtenus avec un modèle NAFR sont présentés dans le but de prouver les possibilités de cette approche comparée à une approche AFR. / The main motivation of this thesis is to be able to predict accurately the fracture of an anisotropic aluminium alloy thin sheet under linear and non-linear strain paths. In the studied case, the material used is the AA6016 and the non-linear strain path considered is uniaxial tension followed by free bending until fracture. Two approaches are considered and compared which respectively use the associated flow rule (AFR) and the non-associated flow rule (NAFR). In order to obtain a good representation of the high anisotropy of the material in AFR, a very flexible yield criterion is used: Yld2004-18p. The identification of its parameters is done with an inverse approach consisting of iteratively minimizing the gap between numerical and experimental results. Once this gap stops evolving (local minimum) or reaches a low enough pre-determined value, the optimization stops and the last updated parameters are saved. In correlation with more recent research work, a NAFR model is used to model the anisotropy of the material. It combines two different yield functions that are used for the yield surface and the plastic potential. Their parameters are identified by using stress ratios and rvalues measured experimentally. Concerning the fracture, uncoupled macroscopic models are studied: a modified Hosford-Coulomb and a DF2014 based criteria. Both these criteria take into account the three invariants of the stress tensor to predict the equivalent strain to fracture but their parameters are identified with different methods to take into account the anisotropy of the fracture. Finally, results on plastic instabilities obtained with a NAFR model are presented in order to prove the possibilities of this approach compared to AFR.

Stångmaterialet 593Y och Q samt trådmaterialet 593B hos Ovako i Hällefors värmebehandlas för att stålet ska få de speciella egenskaper som gynnar efterföljande bearbetningar hos kund. Den värmebehandlingsprocess som stålet genomgår heter mjukglödgning eller sfäroidiseringsglödgning, vilket är en tidskrävande process där strukturella förändringar sker i materialet. Syftet med detta arbete har varit att hitta en värmebehandlingscykel för ovanstående material där produkten möter kundens krav på perlitandel samt hårdhet. För att få en grundläggande förståelse för materialets grundstruktur undersöktes ingångsstrukturen hos vardera material direkt efter valsning samt efter den värmebehandlingscykel som används idag av Ovako i Hällefors. Ingångsstrukturen hos 593Y och B är en finlamellär perlitisk struktur medan 593Q har en fin bainitisk struktur. Den värmebehandlingscykeln som används idag av Ovako i Hällefors värmer upp materialet till 720 ˚C för att sedan svalna ner till 630 ˚C för stångmaterialen samt uppvärmning till 750 ˚C för att svalna ner till 670 ˚C för trådmaterialen. Under mjukglödgningen så bryts cementiten mellan ferritskivorna i grundmassan upp i mindre fragment och antar en sfärisk form tillsammans med att hårdheten i materialet minskas. Mängd kvarvarande perlitisk struktur i grundmassan efter mjukglödgningen bestämmer perlitandelen (PA) i materialet. Analysen utav olika värmebehandlingscykler och undersökning av provbitar genom ljusoptiskt mikroskop tillsammans med Vickers hårdhetsprovning har gett god förståelse och kunskap om hur materialen uppför sig under värmebehandlingen. Med denna kunskap så har en godkänd värmebehandlingscykel tagits fram till stångmaterialen 593Y och Q. Det kommer behövas ytterligare undersökningar och testet för att kunna komma fram med en cykel som passar kundens krav för trådmaterialet.

AOD-slag at Sandvik Materials Technology in Sandviken is disintegrating to a fine powder during cooling as a consequence of a volume increase caused by a phase transformation. The slag becomes a powder that's hard to handle because of dusting, the environment that is closeby take a beating. On top of that the slag must be landfilled and cannot be used as secondary material. In general most slags have a great potential to be used in as construction material in different applications around the society after used by the steel industry. In Sandviks case the disintegration stops that from being possible. To prevent disintegration of AOD-slag serveral things can be done, such as new additives or change of slag composition. In this project a new composition of the slag has been obtained from a decrease of lime addition. Then the slag composition can be moved outside of the area of disintegration by the volume increase. The change had to be done without jeopardize the quality of the steel or the lining material in the AOD. Potential steels were choosen for trials with lowered addition of lime after a present value analysis were established. The early analysis was conducted by slag samples from different steels in the AOD, these samples created the foundation of method further on. The full scale tries were conducted in three campaigns with different follow-ups. The results shows that there is possible to reduce the lime addtive to the AOD and by that receive a solid slag and at the same time produce high quality steel. With reduced lime addition the basicity is lowered. With lowered basicity the results shows that the sulphur removal gets worse as well as the reduction of chromium. The method established in this thesis does no go well with all steels except some pinpointed steel types with less demands on high sulphur removal. / AOD-slaggen vid Sandvik Materials Technology i Sandviken sönderfaller till ett fint pulver under svalning som en konsekvens av en fasomvandling av dikalciumsilikat där en volymexpansion sker. Slaggen som blir pulver blir svårhanterlig på grund av att den dammar, närmiljön försämras till följd. Dessutom måste slaggen deponeras och kan inte användas som ett sekundärt material. Generellt anses slagg har stor potential att användas till andra applikationer i samhället efter användning i stålindustrin. I Sandviks fall sätter sönderfallet stopp för det. För att undvika sönderfall av AOD-slaggen kan en rad olika saker göras som tillsatser eller ändring av sammansättning. I det här projektet har en ny slaggsammansättning uppnåtts genom minskning av kalktillsatsen till slaggen. Då kunde slaggens sammansättning flyttas från området för sönderfall genom volymexpansion. Förändringen var tvungen att ske utan att äventyra stålets kvalité eller infodringen i AOD:n. Potentiella stålsorter valdes ut för försök med mindre kalktillsats efter att en nuvärdesbild hade etablerats. Nuvärdesbilden bestod av provtagning av slagg från charger i AOD:n och den bidrog till metoden för försöken. Fullskaleförsöken utfördes i tre kampanjer med olika typer av uppföljning. Resultaten visar att det är möjligt att minska kalkmängden till AOD:n och därmed få en stabil slagg och samtidigt producera ett fullgott stål. Genom minskad kalktillsats sänks basiciteten och det gör slaggen mindre basisk. Resultaten visar att svavelraffineringen blev sämre. Kromreduceringen blev också något sämre. Metoden framtagen i det här projektet fungerade inte för alla stålsorter utan det är framförallt några utvalda stål med lägre krav på svavelrening.

O trabalho apresentado aqui visou estudar a implantação de elementos em superfícies metálicas (particularmente cobre) de maneira controlada, investigando-se as alterações que tal implante causou na estrutura da superfície, objetivando uma possível melhoria no comportamento desses metais a serem utilizados como catodos em tochas de plasma ou para várias outras aplicações, tais como em catálise, micro eletrônica, oxidação e corrosão de metais e outros. Filmes finos de cobre policristalino foram implantados com íond (energia de 20KeV até 50KeV; doses da ordem de 10 15íons/cm2) de metais alcalinos (Li, Na, K, Rb e Cs) bem como de O e Cl. Foram realizadas diversas análises de superfície visando determinar as alterações ocorridas no cobre quando da implantação dos íons, tais como: composição de superfície (Auger Electron Spectroscopy, X-ray Photoelectron Spectroscopy), estrutura de superfícies em termos de topografia e do potencial de superfície (Kelvin Probe Force Microscopy), composição volumétrica X-ray Fluorescence, Rutherford Backscattering Spectroscopy e Energy Dispersive X-ray Spectroscopy), concentração de oxigênio (Elastic non-Rutherford Backscattering Spectroscopy) e estrutura cristalina (X-ray Diffraction). Modelos teóricos foram utilizados para se obter uma compreensão melhor das alterações estruturais que ocorrem durante a implantação iônica em uma superfície metálica (Stopping and Range of Ions in Matter e Tight-Binding Linear Muffin-Tin Orbital Atomic Sphere Approximation (Coherent Potential Approximation)). As análises de composição superficial mostraram que as concentrações dos elementos C, N, Cl e S dos substratos de cobre não implantados e implantados foram similares e que a única alteração na composição superficial, causada pelo processo da implantação iônica, foi a introdução dos íons desejados nos filmes de cobre. Observou-se que mesmo as pequenas doses de íons podem causar uma grande diminuição da função de trabalho (2-30%) em relação ao cubro puro; já a implantação de O e Cl gerou um aumento na função de trabalho de 300mV e 900MV, respectivamente. As concentrações detectadas de íons implantados de metais alcalinos podem ser consideradas altas (tendo em vista as doses de implantação relativamente pequenas, da ordem de 10.15ions/cm2) diminuindo rápido na direção do bulk das amostras; esta distribuição se deve provavelmente a um processo de migração de íons na direção da superfície. Os resultados de EBS e KPFM indicam que uma maior dose não necessariamente gera uma concentração maior de íons implantados na primeira camada superficial. Observou-se também que somente uma parte da dose total dos íons é efetivamente implantada, devido ao processo de sputtering, que ocorre durante a implantação iônica. A implantação iônica de diferentes íons alcalinos influencia diferentemente os processos de oxidação das amostras. A principal influência no aumento da oxidação é a estrutura topográfica das amostras; porém, a presença de íons implantados nas superfícies das amostras parece influenciar as etapas iniciais de oxidação, aumentando ou diminuindo a absorção de oxigênio. Para o caso da implantação dos íons de O e Cl, a concentração desses íons parece aumentar com a profundidade até um certo nível, o que, por sua vez, indica que não houve um processo de migração durante a implantação. Isto se deve provavelmente ao fato de que estes íons criam ligações com os elementos de substrato. As alterações da função de trabalho de dois casos distintos de deposição de metais (Ag e Cs) sobre Cu (111), foi estudada com o programa TB-LMTO-ASA (CPA), utilizando-se, nas simulações, valores diferentes para o raio de Wigner-Seitz para esferas vazias (WSES); os resultados das alterações da função de trabalho durante a deposição foram aproximadamente 20% menores em comparação com os valores experimentais da literatura. O efeito de WSES, que é, em princípio, um artefato computacional, sobre o valor da função de trabalho do sistema é normalmente interpretado como uma não confiabilidade dos modelos baseados nos conceitos de ASA. Porém, os resultados obtidos durante este trabalho indicam a existência de uma relação entre WSES e a rigorosidade da superfície; portanto, o sentido físico de esferas vazias pode ser visto como uma medida da rugosidade superficial. / In this work, the controlled implantation of the different elements in the metallic surfaces (particularly copper) was performed, in order to study the changes that the implantation causes on the surface structure, aiming to improve the behaviour of those metals for their use as cathodes in plasma torches or other applications, such as: catalysis, microelectronics, oxidation and corrosion of metals and others. Thin polycrystalline copper films were implanted with ions (energy 20-50keV; doses of order of \'10 POT. 15\' ions/\'cm POT. 2\') of alkaline metals (\'LI\', \'NA\', \'K\', \'RB\', and \'CS\') as well as of \'O\' and \'CL\'. Different surface analyses were performed in order to determine the changes on copper due to the ion implantation, in terms of: surface composition (Auger Electron Spectroscopy, X-ray Photoelectron Spectroscopy), topographic and surface potential structure (Kelvin Probe Force Microscopy), bulk composition (X-ray Fluorescence, Rutherford Backscattering Spectroscopy e Energy Dispersive X-ray Spectroscopy), oxygen concentration (Elastic non-Rutherford Backscattering Spectroscopy) and crystalline structure (X-ray Diffraction). Theoretical models were used to understand better the structural changes which occur on the metallic surface during the ion implantation process (Stopping and Range of Ions in Matter e Tight-Binding Linear Muffin-Tin Orbital Atomic Sphere Approximation (Coherent Potential Approximation)). The surface composition analyses of implanted and non-implanted copper substrates showed similar concentration of \'C\', \'N\', \'CL\' and \'S\' and that the only change in surface concentration, due to the ion implantation process, was the introduction of the desired ions in the surface of copper films. It was observed that even small ion doses can cause relatively large decrease of work function (2-30%) in relation to the pure copper value; the implantation of O and CL caused an increase in work function of 300m V and 900mV, respectively. The detected concentration of implanted alkali metal ions was relatively high (taking into consideration relatively small implantation doses, of the order of \'10 POT. 15\' ions/\'cm POT. 2\'), decreasing fast towards bulk of the samples; this distribution were probably caused by a migration process of implanted ions towards the surface. The EBS and KPFM results indicate that not always the largest dose produces the largest implanted ion concentration in the surface layer. It was also observed that only a part of the total ion dose is effectively implanted, due to the sputtering during the ion implantation process. Implantation of different alkali ions influences the sample oxidation process in a different way. The principal influence in the increase of oxidation is the topographic structure of the samples; however, the presence of the implanted ions on the samples surface seems to influence the initial stages of the oxidation, increasing or decreasing the oxygen adsorption. Of the cases of the O and CL implantation, the concentration of these ions seems to increase with depth, which indicates that there were no migration process involved. This is probably due to the fact that these ions create bonds with the substrate elements. The changes in the work function for two distinct cases of metal (AG and CS) deposition on CU (111) was studied with the computational programme TB-LMTO-ASA (CPA), using, in the simulations, different values for the Wigner-Seitz radius for Empty Spheres (\'WS IND. ES\'); the results on the work function changes during the deposition were approximately 20% lower in comparison with the experimental data from the literature. The effect of \'WS IND. ES\', which is, in principle, a computation artefact, on the work function value of the studied systems is normally interpreted as the non-reliability of the models based on the ASA concepts. However, the results obtained during this work indicate that there is a relation between the \'WS IND. ES\' and the surface roughness; therefore, physical meaning of the empty spheres can be understood as a \"measure\" of surface roughness.

Denna rapport är ett examensarbete utfört på Ovako Bar AB i Smedjebacken, vilket är det avslutade momentet i utbildningen ”Materialteknik med inriktning metallurgi” på Bergsskolan i Filipstad.   Grunden till detta arbete ligger hos ”frysningar” (att stålet slutar rinna från gjutlådan) som företrädesvis sker på yttersträngarna. Igensättning av denna typ orsakas generellt av två faktorer, för låg övertemperatur i förhållande till likvidustemperatur eller otillräcklig förvärmning av gjutlåda samt gjutrör.   Syftet med detta arbete har varit att fokusera på förvärmningen, där målet var att utvärdera hur förvärmningstider ser ut i förhållande till de föreskrivna. Samt utvärdera prestandan hos värmningsutrustningen. Och utvärdera hur temperaturfördelningen ser ut i gjutlådan under gjutning.   Arbetet utfördes med hjälp av termoelement som monterades in i gjutlådan vid 1: a sträng och 3:e sträng för att kunna se hur temperaturfördelning är i gjutlådan. Mätningarna visade tydligt att temperaturen skiljde sig mellan yttersträng (1: a) och centrumsträng (3:e) vilket kan var en orsak till att frysningar sker företrädesvis på yttersträng där temperaturen visat sig vara lägre än centrumsträng.   Vid utvärdering av prestandan på värmningsutrustningen så användes en handpyrometer som möjliggjorde mätning av gjutrören för att ta fram en trendkurva, som visar när temperaturökningen avtar och upphör. Vilket visade brister i tid och prestanda i nuläget.   Med en fullt fungerande förvärmning skulle igensättningsgraden kunna minskas.

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