Graduation theses consist of two parts. The first one, theoretical is focused on piece of knowledge regarding nodular iron history, its mechanical properties, chemistry, production and heat treatment. Theoretical part also includes information relating to graphite and white irons that relate closely with nodular iron. Important chapter is description of isothermal refining which is the subject of these theses. The second, experimental part is focused on isothermal refining of nodular iron casting. Description of the casting introduces this section, material specification, production and application. Following chapters describe preliminary conditions for isothermal refining that is applied on every single specimen made of the casting. These specimens have been tested mechanically. Optimal procedure of isothermal refining is applied on whole the casting and characterized final mechanicals. Final mechanical properties after casting isothermal refining has been analyzed and confronted with literature.

Diploma thesis is specialized in an engineering design of mobile equipment for the surface hardening. At first, overview of methods and instruments for surface hardening is introduced. Solution to the thesis is a proposial for any eventual options of contruction, appreciation and choice of a suitable option. Subsequently, particular parts of the equipment with design and check calculations are explicated. Constructional tasks were done in the SolidWorks program. Finally, an economical analysis is described.

This diploma thesis continues to the Ing. Damborský work and deals with strain-stress and dynamic analysis of the steam turbine blade. This blade is part of the last row of low pressure level of steam turbine. Computational analysis has been performed in first part using FEM. After that follows a modal analysis for the blade without residual stress as well as for the blade affected by heat treatment. Main goal is to obtain whether the state of stress is in the crack initiation area is influenced by thermal treatment. This problem was solved by computational simulation in commercial software Ansys 11.0.

Diploma thesis is focused on laser hardening by Yb:YAG fiber laser. Experiment is based on hardening of testing pieces made of steel 12 050 with different parameters of distance and movement speed of laser head. In theoretical part are described principle of laser, types of lasers, laser technology in industry, types of lasers, types of hardening and types of hardness measuring. In practical part are firstly evaluated macrostructure and microstructure photos and Vickers hardness. In conclusion are analyzed the results of laser hardening and after that the best laser hardening parameters were selected.

The goal of the thesis was research in the field of structure and properties of low alloyed steels used in low temperature environment. Work was focused on heat treatment and chemical composition of the steel and their impact to hardness and impact energy values. Chemical composition and heat treatment of steel was proposed on the basis of achieved results.

ZELNÍČKOVÁ Marta: Optimizing of heat treatment of casting produced by SEED method. This work deals with designing optimum heat treatment method for casting alloy AlSi7Mg0,3, cast by SEED. Different temperature and times are tested in regimes of heat treatment, mechanical properties are determined with dependence of on the heat treatment method and optimal temperature regime is determined from the detected values.

CoCr-Legierungen wurden und werden für orthopädische Implantate verwendet, da sie eine Kombination aus hoher Festigkeit, Korrosionsbeständigkeit und Biokompatibilität ermöglichen. Seit 1985 wurden metallische Implantate umfassend untersucht, die mit Calciumphosphaten beschichtet sind, um die Biokompatibilität und die Anindung an das angrenzende Knochengewebe zu verbessern. Trotz des Fortschritts und der Entwicklung vieler Technologien ist die Ausfallrate solcher Implantate immer noch ein Problem. In der vorliegenden Arbeit wurde ein neuer und einfacher Weg entwickelt, um eine Hydroxylapatit (HAp) -Beschichtung auf einer CoCr-Legierung vermittels einer Suspension aus umweltfreundlichem Kiefernöl (PO), das mit HAp-Partikeln gemischt ist, zu erhalten. Die HAp-Beschichtung wurde unter Verwendung eines Pinsels auf den CoCr-Substraten aufgebracht, gefolgt von einer Wärmebehandlung bei 800°C für 1 Stunde, um die Haftung zwischen dem Substrat und der Schicht zu verbessern. Verschiedene durch Polieren, Passivieren und einer Wärmebehandlung hergestellte Oberflächenmorphologien sowie ein unbehandeltes Substrat wurden getestet und dann beschichtet, um den Einfluss der Rauheit auf die Wechselwirkung zwischen Substrat und Beschichtung zu bewerten. Die Benetzbarkeit wurden wurde durch Kontaktwinkelmessungen bestimmt. Der Kontaktwinkel von Wasser auf den Metallimplantatoberflächen war viel höher (68°) als der von PO (23°), was einen homogeneren Beschichtungsprozess ermöglichte, wenn PO für die HAp-Suspension verwendet wurde. Rasterelektronenmikroskopie- (REM), Röntgenbeugungs- (XRD) und Fourier-Transform-Infrarotspektroskopie (FTIR) -Analysen ergaben, dass die Substrate vollständig mit reinem HAp bedeckt waren. Die Wechselwirkung zwischen Substrat und Beschichtung wurde mittels REM, optischem Profilometer und Bleistift-Kratztest analysiert. Es wurde eine gute Partikelverteilung und für alle getesteten Oberflächenmorphologien eine stabile Bindung zum Substrat nachgewiesen. Die in vitro in simulierter Körperflüssigkeit (SBF) durchgeführten Bioaktivitätstests zeigten eine hohe Beständigkeit gegen Abbau und es wurde eine verringerte Bildung von Rissen auf den Oberflächen nach 21 Tagen Auslagerung beobachtet. Potentiodynamische Polarizations- und Cyclovoltammetrieanalysen bestätigten, dass die beschichteten und unbeschichteten Proben eine gute Korrosionsbeständigkeit zeigten. Die HAp-Beschichtung auf dem passivierten Substrat zeigte im Vergleich zu unbeschichteten Proben eine überlegene Korrosionsbeständigkeit, und es kann angenommen werden, dass hierbei die HAp-Beschichtung den Oberflächenschutz gegen Korrosion verbessert. Die Hochtemperaturbehandlung förderte jedoch die Abnahme der Korrosionsbeständigkeit im Falle des beschichteten, polierten Substrats, was auch das Wachstum von menschlichen primären Zellen aus Knochengewebe beeinflusste, die für in vitro-Zytokompatibilitätstests der verschiedenen Oberflächenmodifikationen verwendet wurden. Um die hohen Kosten und die Komplexität der konventionellen Abscheidungsmethoden und das damit verbundene Risiko einer Phasenumwandlung von HAp zu überwinden, bietet diese Arbeit eine einfache und effiziente Möglichkeit, HAp als mögliche Alternative zur Verbesserung von Knochenimplantaten auf metallische Substrate aufzutragen.:List of Figures vi List of Tables ix List of Abbreviations x Summary xi 1. Introduction 1 1.1 Objective 3 2. Literature review 4 2.1 Metallic biomaterials 4 2.1.1 Co-based alloys 5 2.1.2 Corrosion of CoCr alloys 7 2.2 Surface of metallic implants 11 2.3 Interface between substrate and coating 12 2.4 Cell-surface interaction 13 2.5 Calcium phosphates (CaP) 15 2.5.1 Hydroxyapatite 15 2.6 HAp coating 16 2.6.1 HAp coating methods 16 3. Materials & methods 27 3.1 Synthesis and characterization of HAp powder 27 3.2 Preparation of metallic substrate 27 3.3 Thermal behavior of the Pine Oil 28 3.4 HAp/pine oil slurry preparation and coating process 28 3.5 Characterization of the coating 29 3.6 Surface topography and wettability 29 3.7 Scratch resistance of the coating 29 3.8 Corrosion tests 30 3.8.1 Cyclic voltammetry 31 3.8.2 Potentiodynamic polarization 31 3.9 In vitro bioactivity analyses 33 3.10 Cell culture 34 4. Results & Discussion 36 4.1 Characterization of HAp powder 36 4.2 Thermal characterization of the pine oil 38 4.3 Characterization of the coating surface 40 4.3.1 X-ray diffraction and FTIR analyses 43 4.4 Surface properties 45 4.4.1 Topography, roughness and wettability 45 4.5 Scratch resistance of the coating 50 4.6 In vitro bioactivity and morphology 53 4.7 Metallography of the Co-15Cr-15W-10Ni alloy 62 4.8 Corrosive behavior 63 4.8.1 Effect of heat treatment on corrosion resistance 66 4.9 Cell Proliferation and osteogenic differentiation 68 5. Conclusions 73 5.1 Future perspectives 74 6. References 75 Acknowledgements 90 / CoCr alloys have been used for orthopedic implants as they allow combining high strength, corrosion resistance and biocompatibility. Since 1985 metallic implants coated with calcium phosphates have been widely studied to improve the biocompatibility and adequate bonding to the adjacent bones, but despites of advances and development of many technologies, rate of failure of such implants still are a problem. In the present work, a novel and simple route was developed to obtain hydroxyapatite (HAp) coating on CoCr alloy from a slurry of eco-friendly pine oil (PO) mixed with HAp particles. The HAp coating was deposited onto CoCr substrates using a paint brushing followed by heat treatment at 800°C for 1 h in order to improve the adhesion between the substrate and coating. Several substrate surface morphologies made by polishing, passivation, heat treatment and remaining the substrate untreated were tested, and then coated to evaluate the influence of the roughness on the interaction between substrate and coating. Wettability tests were carried out by sessile drop method; the contact angle of water on the metal implant surfaces was much higher (68°) than that of PO (23°), allowing a more homogeneous coating process when PO was used for HAp suspension. Scanning Electron Microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) analyses indicated a substrate fully covered by pure HAp. The interaction between substrate and coating was analyzed by SEM, optical profilometer and pencil scratch tests. Good particle distribution and tight bonding to the substrate were found for all surfaces morphologies tested. The bioactivity tests in vitro performed in simulated body fluid (SBF) showed high resistance to degradation and a decreased formation of cracks was observed on the surfaces after 21 days of soaking. Potentiodynamic polarization and cyclic voltammetry analyses corroborated that the coated and uncoated samples showed good corrosion resistance. The HAp coating on the passivated substrate presented a superior corrosion resistance compared to uncoated ones and it can be assumed that the HAp coating improve the surface protection against corrosion. However, the high temperature treatment promoted decrease of corrosion resistance in case of the coated polished substrate, which also affected the growth of human primary bone-derived cells which were used for in vitro cytocompatibility tests of the different surface modifications. In order to overcome the high costs and complexity of the conventional deposition methods and the risk of phase transformation of HAp, related to those, this thesis presents a straightforward and efficient route to coat HAp onto metallic substrates as a potential alternative for improvement of bone implants.:List of Figures vi List of Tables ix List of Abbreviations x Summary xi 1. Introduction 1 1.1 Objective 3 2. Literature review 4 2.1 Metallic biomaterials 4 2.1.1 Co-based alloys 5 2.1.2 Corrosion of CoCr alloys 7 2.2 Surface of metallic implants 11 2.3 Interface between substrate and coating 12 2.4 Cell-surface interaction 13 2.5 Calcium phosphates (CaP) 15 2.5.1 Hydroxyapatite 15 2.6 HAp coating 16 2.6.1 HAp coating methods 16 3. Materials & methods 27 3.1 Synthesis and characterization of HAp powder 27 3.2 Preparation of metallic substrate 27 3.3 Thermal behavior of the Pine Oil 28 3.4 HAp/pine oil slurry preparation and coating process 28 3.5 Characterization of the coating 29 3.6 Surface topography and wettability 29 3.7 Scratch resistance of the coating 29 3.8 Corrosion tests 30 3.8.1 Cyclic voltammetry 31 3.8.2 Potentiodynamic polarization 31 3.9 In vitro bioactivity analyses 33 3.10 Cell culture 34 4. Results & Discussion 36 4.1 Characterization of HAp powder 36 4.2 Thermal characterization of the pine oil 38 4.3 Characterization of the coating surface 40 4.3.1 X-ray diffraction and FTIR analyses 43 4.4 Surface properties 45 4.4.1 Topography, roughness and wettability 45 4.5 Scratch resistance of the coating 50 4.6 In vitro bioactivity and morphology 53 4.7 Metallography of the Co-15Cr-15W-10Ni alloy 62 4.8 Corrosive behavior 63 4.8.1 Effect of heat treatment on corrosion resistance 66 4.9 Cell Proliferation and osteogenic differentiation 68 5. Conclusions 73 5.1 Future perspectives 74 6. References 75 Acknowledgements 90 / Ligas de CoCr têm sido empregadas em implantes ortopédicos por permitirem a combinação de alta resistência mecânica, resistência a corrosão e biocompatibilidade. Implantes metálicos revestidos com fosfatos de cálcio têm sido estudados desde 1985 devido a sua capacidade de aumentar a biocompatibilidade e promover a ligação adequada com os ossos adjacentes. No entanto, apesar de todos os avanços e o desenvolvimento de muitas tecnologias, a taxa de falha destes implantes ainda é um problema. No presente trabalho, uma nova e simples rota foi desenvolvida para revestir a liga de CoCr com hidroxiapatita (HAp) a partir de uma mistura óleo de pinho (PO) ecológica com partículas de HAp. O revestimento de HAP foi depositado sobre o substrato de CoCr usando uma pincel de pintura seguido de tratamento térmico a 800 °C por 1 h a fim de aumentar a adesão entre o substrato e o revestimento. Foram testadas diversas morfologias de superfície do substrato, sendo estas polidas, passivadas, tratadas termicamente, além de um substrato não tratado, e em seguida foram revestidas para avaliar a influencia da rugosidade na interação entre substrato e revestimento. Testes de molhabilidade foram realizados pelo método de gota séssil; o ângulo de contato da água na superfície metálica do implante foi muito maior (68°) que os com PO (23°), permitindo uma maior homogeneidade no processo de revestimento quando utilizado PO na suspensão de HAp. Análises por Microscopia Eletrônica de Varredura (MEV), difração de raio-x (DRX) e espectroscopia infravermelha por transforma de Fourier (FTIR) indicaram que o substrato foi completamente coberto com a HAp pura. A interação entre o substrato e o revestimento foi analisada por MEV, perfilômetro óptico e teste de arrancamento, os quais demonstraram uma boa distribuição de partículas e uma próxima ligação para todas as morfologias de superfície testadas. Testes in vitro de bioatividade foram realizados com fluido corpóreo simulado (SBF) e apresentaram alta resistência a degradação e uma redução da formação de trincas na superfície foi observada após 21 dias de imersão. Análises de polarização potenciodinâmica e voltametria cíclica comprovaram uma boa resistência à corrosão nas amostras revestidas e não revestidas. O revestimento de HAp no substrato passivado apresentou uma resistência à corrosão superior aos não revestido e pode ser assumido que o revestimento de HAp melhorou a proteção da superfície contra corrosão. No entanto, o tratamento térmico com alta temperatura promoveu uma diminuição da resistência à corrosão no caso do substrato polido revestido, no qual afetou o crescimento de células primárias derivadas de osso humano que foram usadas nos testes de citocompatibilidade in vitro nas diferentes superfícies modificadas. A fim de solucionar o alto custo e a complexidade no método convencional de deposição, além dos riscos da transformação de fase da HAp, esta tese apresenta uma direta e eficiente rota de revestimento de HAp em substratos metálicos como uma potencial alternativa para o melhoramento de implantes ósseos.:List of Figures vi List of Tables ix List of Abbreviations x Summary xi 1. Introduction 1 1.1 Objective 3 2. Literature review 4 2.1 Metallic biomaterials 4 2.1.1 Co-based alloys 5 2.1.2 Corrosion of CoCr alloys 7 2.2 Surface of metallic implants 11 2.3 Interface between substrate and coating 12 2.4 Cell-surface interaction 13 2.5 Calcium phosphates (CaP) 15 2.5.1 Hydroxyapatite 15 2.6 HAp coating 16 2.6.1 HAp coating methods 16 3. Materials & methods 27 3.1 Synthesis and characterization of HAp powder 27 3.2 Preparation of metallic substrate 27 3.3 Thermal behavior of the Pine Oil 28 3.4 HAp/pine oil slurry preparation and coating process 28 3.5 Characterization of the coating 29 3.6 Surface topography and wettability 29 3.7 Scratch resistance of the coating 29 3.8 Corrosion tests 30 3.8.1 Cyclic voltammetry 31 3.8.2 Potentiodynamic polarization 31 3.9 In vitro bioactivity analyses 33 3.10 Cell culture 34 4. Results & Discussion 36 4.1 Characterization of HAp powder 36 4.2 Thermal characterization of the pine oil 38 4.3 Characterization of the coating surface 40 4.3.1 X-ray diffraction and FTIR analyses 43 4.4 Surface properties 45 4.4.1 Topography, roughness and wettability 45 4.5 Scratch resistance of the coating 50 4.6 In vitro bioactivity and morphology 53 4.7 Metallography of the Co-15Cr-15W-10Ni alloy 62 4.8 Corrosive behavior 63 4.8.1 Effect of heat treatment on corrosion resistance 66 4.9 Cell Proliferation and osteogenic differentiation 68 5. Conclusions 73 5.1 Future perspectives 74 6. References 75 Acknowledgements 90

Invasiva växtarter är ett globalt problem som hotar inhemska ekosystem. Blomsterlupinen (Lupinus polyphyllis) är en invasiv flerårig växt som erhåller flera egenskaper som bidrar till dess framgångsrika etablering och spridning. Vägkanter agerar som landskapskorridorer för exotiska arter samtidigt som det är en viktig habitatrefug för många ängsväxter. För att effektivisera bevarandeåtgärder behövs en gedigen kunskap om målarten och dess egenskaper. Syftet med den här studien var att utvärdera två potentiella hanteringsmetoder av blomsterlupin i vägkanter. Slåtter är en redan etablerad strategi, men för att ta reda på om olika skördintensiteter påverkar återväxten av biomassa på olika sätt jämfördes en kontrollgrupp (ej skörd) och tre skördgrupper (1–3 skördar) med avseende på bladbiomassa, stambiomassa, blomställningsbiomassa och plantans totala biomassa. En annan potentiell hanteringsmetod utvärderades med fokus på fröbanken. Frön från blomsterlupin värmebehandlades i 40°C, 50°C och 70°C, och jämfördes mot frön utsatta för kontrolltemperatur (20°C). Varaktigheten för värmebehandlingar var 1, 5 och 15 minuter. Några frön utsattes för vattenbehandling innan värmebehandlingen för att bryta den fysiska vilan. Blomsterlupinfrön jämfördes mot tre andra arter i familjen ärtväxter (Fabaceae); blodklöver (Trifolium incarnatum), blålusern (Medicago sativa) och (Louts corniculatus). Det fanns en signifikant effekt beroende av skördintensitet på återväxt av stambiomassa, blomställningsbiomassa och plantans totala biomassa. Gällande bladbiomassa fanns ingen skillnad mellan grupperna. Faktumet att blomsterlupinen primärt investerar mer resurser på produktion av bladbiomassa kan anses positivt ur ett åtgärdsperspektiv. Återväxten av biomassa var emellertid beroende av plantans ursprungliga storlek, således skulle effekten av slåtter kunna skilja sig mellan individer i en population. Vattenbehandlingen bröt inte den fysiska vilan hos blomsterlupinfrön. Men en ökad temperatur under värmebehandlingen verkade ha en hämmande effekt för antalet grodda frön och MGT. Trots det återfanns ett relativt stort antal levande blomsterlupinfrön efter den sista observationsdagen. Det kan indikera att många frön skulle överleva en värmebehandling av fröbanken om behandlingen skulle implementeras som åtgärdsmetod. Metoden skulle förmodligen vara tidskrävande och dyr i förhållande till den önskade reducerande effekten på levande blomsterlupinfrön. För att utveckla resurseffektiva åtgärder för artens fröbank krävs mer kunskap. Slåtter verkar vara en bättre åtgärdsmetod om det genomförs vid rätt tidpunkt två gånger om året. / Invasive plant species are a global problem that threaten native ecosystems. The garden lupin (Lupinus polyphyllus) is an invasive perennial herb and possesses several traits, which enables successful establishment and dispersal. Road verges serve as landscape corridors for exotic species, as well as being an important refuge habitat for many grassland species. To make conservation managements more efficient, an extensive knowledge of the target species and it’s traits is required. The aim of this study was to evaluate two potential management strategies for garden lupin in road verges. Mowing is an established strategy already, but to find out if different cutting intensities will affect biomass regrowth differently, one control group (no cut) and three harvest groups (1-3 cuts) were compared regarding leaf biomass, stem biomass, inflorescence biomass and total plant biomass. Another potential management strategy was evaluated focusing on the seed bank. Seeds of garden lupin were heat treated at 40 °C, 50 °C, and 70 °C and compared to control seeds (20 °C). Duration of treatments was 1, 5, and 15 minutes. Some seeds were watered before the heat treatment to break physical dormancy. Seeds of garden lupin were compared to three other species in the Fabaceae family: Trifolium incarnatum, Medicago sativa, and Lotus corniculatus. I found a significant effect of cutting frequency on regrowth of stem biomass, inflorescence biomass, and total plant biomass. Regarding leaf biomass, there was no difference between harvest groups. The fact that garden lupin plants primarily invest more resources in leaf biomass regrowth can be regarded as positive from a management point of view. However, biomass regrowth was depended on initial plant size, and the mowing response might differ between individual plants in populations. The water treatment did not break the physical dormancy of garden lupin seeds. Increased temperatures during heat treatments seemed to have an inhibiting effect on both seed germination and mean germination time. However, a high number of vital garden lupin seeds were remaining after the last observation. This might indicate that many seeds would remain vital if seed bank heat treatments were implemented as a management strategy. The strategy would probably be time consuming and expensive in relation to the desired reducing effect on vital garden lupin seeds. To develop resource efficient management actions on the species’ seed bank, more knowledge is needed. Mowing seems like a better management option if it is implemented at the right time twice a year.

The average size of hot-work tools has gradually increased over the past years.This affects the effective temperature cycle tools experience during hardening,as large dimensions prevent uniform and rapid cooling, and thereby the resulting microstructures and properties. In order to avoid the formation of coarse structures or cracking during heat treatment it has become common practise to lower the austenitising temperature below that recommended by the steel manufacturer.In this work, therefore, the effects of austenitising at temperatures lower thancommonly recommended are investigated. Three 5% Cr hot-work tool steelsalloyed with Mo and V were heat treated, resulting microstructures andtempering carbides were studied and transformation characteristics determined for different austenitising temperatures and different cooling rates. The temperatures and cooling rates have been chosen to be representative for heat treatments of different sizes of tools. Bainite rather than martensite formed during slow cooling regardless of austenitising temperature. A lowered austenitising temperature produced largeramounts of both bainite and retained austenite while a higher caused graingrowth. Carbon partitioning during the bainitic transformation resulted in anincrease of the carbon content in the retained austenite of at least 0.3 wt.%. The austenitising temperature influences also the type and amount of tempering carbides that precipitate, which affects the properties of the steel. Higher austenitising temperatures favour the precipitation of MC carbides during tempering. The Mo rich M2C type carbides were proven to be more prone to coarsening during service at 560°C-600°C, while V rich MC carbides preserve their fine distribution. A best practice heat treatment needs to balance the increase of grain size with increasing austenitising temperatures, with the possibility to form more tempering carbides. Higher austenitising temperatures also give less retained austenite, which can affect dimensional stability and toughness negatively after tempering

Export of heat treated steel goods has an important impact on the Swedish economy which brings performance demands and expectations on production to keep a competitive market position. Sustainability and efficiency are two important aspects in meeting these demands. This thesis studies how a data driven approach can be used to increase efficiency in manufacturing of rods produced for the mining industry.  The purpose of this thesis is to use a machine learning model suitable for classifying quality results for heat treated steel rods. This is done by comparing nine algorithms with the objective to tune and deploy the model best fitted while gaining insights in variables that have an impact on the quality output.  This thesis outset is a heat treatment process at Epirocs facility in Fagersta. Interviews are conducted to gain domain knowledge about important features and an AI pipeline is implemented to demonstrate its suitability for predicting quality given production and weather data in the form of time series and product-unique data points.  The result of the study shows that the machine learning algorithm random forest is indicated as most suitable among the analyzed. The study also shows that an AI pipeline with streaming data can be designed and efficiently implemented for quality improvement. Through this work, the authors have proved that machine learning can be used to improve the heat treatment process of rods, but the model still has room for improvement in feature selection and availability of larger and more detailed data at the facility.