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Anish, Thottathil Viswanathan. "Age strengthening of gray cast iron: alloying effects and kinetics study." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/Anish_09007dcc805b9ca9.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed October 25, 2007) Includes bibliographical references (p. 82-83).
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Chen, Zhen-da. "Laser surface melting and alloying of cast irons." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/38260.
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Walker, Andrew Meredith. "Laser surface alloying of metallic substrates with carbon and silicon." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38178.
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Kasap, Yücel. "Optimization of the Chemical Analysis SS-EN-GJL-250 Using Casting Simulation Software." Thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Maskinteknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-15904.
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The main purpose of the thesis work is based on achieving same mechanical properties on the three different sized bearing housings. The key mechanical property that had to be focused on was the hardness of the parts. In order to achieve this goal, chemical compositions of the parts have studied. However there were some limitations on the composition variants. Allowed variables of the compositions are silicon, nickel and copper. Due to necessity another element, Molybdenum (Mo), was also introduced. After many simulations three different compositions are proposed. Then the feasibility of results of casting simulation software investigated. And finally an optimization guideline has proposed. Chemical composition researches have carried on casting simulation software, which is called Magma5. Following the completion of the simulations phase, proposed compositions trial casted at the company. Subsequent to trial castings cast parts had tested for their hardness values. In order to bring the thesis to completion simulation outputs and trial test results had compared. With the help of a casting simulation software composition optimisation of different sized parts could be easily optimised in order to achieve same results. Many simulations are executed with different composition for the silicon, nickel, copper and molybdenum variants. It was seen that Mo additions significantly increase the mechanical properties of the parts. Nickel and copperacts similarly on the hardness values, however nickel addition reduce undercooling tendency at a greater rate. Good inoculation is vital for the parts with thin sections. Decent inoculation helps to improve the microstructure and helps to get closer results tothe simulated values. However software represents key information aboutundercooled zones on the part. Software ensures 95% to 97% correct values on hardness results.
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Procházka, Jan. "Vliv opravného zavařování za tepla na změnu struktury a tvrdost odlitků z litiny s lupínkovým grafitem." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400486.
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The master‘s thesis deals with the influence of the thermal cycle of welding with preheat on castings made of grey cast iron to change the hardness. The thesis deals with the classification of graphitic cast irons, their structure, properties and influences they have on the formation and transformation of the structure. Emphasis is placed on chemical composition and structure stability at elevated temperatures. The practical part deals with the investigation of the effects of casting repair on the decrease of hardness measured in the foundry Heunisch Brno.
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Rosario, Adriano Murilo. "ESTUDO DOS EFEITOS DE ELEMENTOS DE LIGA NA SOLIDIFICAÇÃO DE UM FERRO FUNDIDO CINZENTO VIA ANÁLISE TÉRMICA." UNIVERSIDADE ESTADUAL DE PONTA GROSSA, 2012. http://tede2.uepg.br/jspui/handle/prefix/1448.
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Previous issue date: 2012-10-22The present study aimed at analyzing the effects of alloying elements on the solidification curves of a gray cast iron using the thermal analysis technique. Inoculation was performed by adding of only 0.02% (in wt. %) of IM22 inoculant, in order to minimize undercooling and provide a minimal quantity of nucleation sites for graphite during solidification. A constant inoculation condition allows highlighting the influence of alloying elements in the cooling curves, as well as in the solidification parameters. The following elements have been added to the base metal (in wt. %): selenium (0.2% to 0.5%), nickel (0.2% to 0.5%), iron-phosphorus (0.2% to 1.0%), silicon (0.05% to 0.4%), lead (0.2% to 1.0%) and tin (0.2% to 0.8%). The elementary powders were characterized by scanning electron microscopy (SEM) with energy-dispersive X-ray microanalysis (EDX). The base metal was produced in a medium frequency induction furnace and its chemical composition corresponded to a FC-25 class. The samples obtained after the addition of alloying elements were characterized by optical microscopy, optical emission spectrometry, tensile and hardness tests. The results showed that selenium has a strong effect on undercooling, favoring the formation of eutectic carbides. Nickel tends to favor the formation of type "A” graphite. The phosphorus has the effect of reducing the tensile strength of gray iron and promotes the formation of steadite, consisting of the eutectic of ferrite and iron phosphide (Fe3P). The silicon favors the formation of type "A" graphite. Lead has deleterious effect on the morphology of graphite. Tin has the effect of increasing the mechanical properties. The use of thermal analysis technique allowed the finding of good correlations between the different solidification parameters studied. The stable and metastable eutectic temperatures are strongly affected by the alloying elements. Finally, new equations for the temperatures of stable and metastable eutectics are proposed. The equations are based on experimental results and data extracted from ATAS program.
O presente trabalho teve por objetivo principal analisar os efeitos dos elementos de liga nas curvas de solidificação de um ferro fundido cinzento, utilizando a técnica de análise térmica. A inoculação foi adicionada em um teor muito abaixo do utilizado na indústria metalúrgica, ou seja, de apenas 0,02% do inoculante IM22. O suficiente para haver número mínimo de substratos para a grafita nuclear durante a solidificação. A condição de inoculação constante teve por objetivo destacar a influência dos elementos de liga estudados nas curvas de resfriamento, bem como nos parâmetros de solidificação. Os seguintes elementos foram adicionados ao metal base: selênio (0,2 a 0,5% em peso), níquel (0,2 a 0,5% em peso), ferro-fósforo (0,2 a 1,0% em peso), silício (0,05 a 0,4% em peso), chumbo (0,2 a 1,0% em peso) e estanho (0,2 a 0,8% em peso). Os pós destes elementos foram caracterizados por microscopia eletrônica de varredura (MEV) com microanálise química por dispersão de raios x (EDS). O metal base foi fundido em um forno de indução de média frequência, sendo sua composição característica de um ferro fundido cinzento de classe FC-25, corrigindo-se apenas o carbono e o silício. As amostras obtidas após a adição dos elementos de liga foram caracterizadas por microscopia óptica, espectrometria de emissão óptica e ensaios mecânicos de tração e dureza. Os resultados mostram que o selênio possui um forte efeito no super-resfriamento, favorecendo a formação de carbetos eutéticos. O níquel tende ao favorecimento da formação da grafita do tipo “A”. O fósforo tem o efeito de diminuir a resistência à tração do ferro fundido cinzento e promove a formação de “esteadita”. O silício favorece a formação da grafita do tipo “A”. O chumbo tem efeito deletério na morfologia da grafita. O estanho tem o efeito de aumentar as propriedades mecânicas. A utilização da técnica de análise térmica permitiu encontrar uma boa correlação entre os diversos parâmetros de solidificação estudados. Os resultados mostram que os elementos de liga atuam fortemente nas temperaturas do eutético estável e do eutético metaestável. Por fim, são propostas novas equações para o cálculo das temperaturas dos eutéticos estável e metaestável. As equações são baseadas nos resultados experimentais e nos dados do programa ATAS.
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Tesařová, Hana. "Strukturní a mechanické charakteristiky niklových litin s kuličkovým grafitem." Doctoral thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2010. http://www.nusl.cz/ntk/nusl-233891.
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The aim of this dissertation work is the evaluation of the influence of nickel alloying on the structure and mechanical properties, both monotonic and dynamic, of nodular cast iron with ferritic and bainitic matrix. Two chock melts with 0.5 and 2.7 % Ni were used to study the nickel influence. The quantitative evaluation of structure of these melts using image analysis was done and basic tensile mechanical properties were determined. Subsequently, the time optimization of two-stage ferritic annealing and isothermal austempered heat treatment at 375 °C was performed with the aim to obtain optimal ferritic and bainitic structures with best static and dynamic mechanical properties. After ferritic annealing the nickel alloying contributes to substitution hardening of ferritic matrix which positively affects its strength and other mechanical properties. The higher nickel content in the bainitic structure causes the shift of phase transformation times to longer times which results in restricted production of small carbides and in bigger volume of retained austenite. These features were confirmed by observation in transmission electron microscope. Precise tensile and low cycle fatigue tests at temperatures 23 and – 45 °C were performed on the optimized structures of both nodular cast irons. As a result of the notch effect of graphite nodules, microplastic deformation of both nodular cast irons was observed at stresses which were lower than the yield stress. The Hollomon's equation very well describes the individual parts of tensile curves for both nodular cast irons including their mutual comparison. From the low cycle fatigue tests, the cyclic hardening/softening curves, the evolution of elastic modulus and hysteresis loop shape parameters, cyclic stress-strain curves and fatigue life curves were obtained for both temperatures and materials. Moreover, the decrease of retained austenite volume was measured by neutron diffraction and the evolution of surface relief was characterized during cyclic straining for both austempered nodular cast irons at both temperatures. On the basis of these results both cyclic plasticity and fatigue degradation mechanisms in relation to the cyclic strain localization were described for both nodular cast irons.
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Li, Jing. "Alloying effect on boride formation behaviour in cast TiAl alloys." Thesis, University of Birmingham, 2017. http://etheses.bham.ac.uk//id/eprint/7170/.
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Boron addition has been used to refine the microstructures in TiAl castings, such as LPT blades, to improve ductility. However, boride precipitates with undesired morphologies could reduce ductility and even wipe out the entire benefit from grain refinement. Boride morphology in Ti45Al2Mn2Nb1B was found to be closely related to solidification conditions and proper processing windows have been established. In order to improve temperature capability of cast TiAl alloys to cater for the demand in new engines TiAl alloys have to be alloyed with more refractory elements, such as Nb and Ta, which will inevitably affect the boride morphologies. In this study variant alloys based on Ti45Al2Mn2Nb1B have been investigated with emphasis on the relationship between boride morphology, alloying element species and cooling conditions and distinctly different boride formation behaviour in different alloys was observed. In addition, curvy borides were found both on the fracture surface and within the microstructure in tensile test pieces, especially in Hf-containing test pieces, which indicate that curvy borides have the strongest effect in reducing ductility regardless of alloy composition.
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Boeri, Roberto Enrique. "The solidification of ductile cast iron." Thesis, University of British Columbia, 1989. http://hdl.handle.net/2429/30598.
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The microsegregation of Mn, Cu, Cr, Mo, Ni and Si has been measured in cast ductile iron and in ductile iron which has been quenched when partially solidified. Effective segregation coefficients have been determined for each of the elements, and used to calculate the segregation on the basis of the Scheil equation. The calculated values agree reasonably well with the values of the solute concentration as a function of the solid fraction measured in quenched samples.
The microstructure of the solid phases during the solidification of ductile iron has been observed. Solidification of eutectic ductile iron begins with the independent nucleation of austenite and graphite in the melt. Later the graphite nodules are enveloped by austenite, and further solidification takes place by the thickening of the austenite layers enveloping the graphite. Isolated pockets of interdendritic melt are the last material to solidify.
On the basis of the measured segregation of the different alloying elements, the mechanisms by which the segregation affects the microstructure are considered, and an explanation for the effect of segregation on the hardenability of ductile iron is proposed.
A mathematical model of the solidification of eutectic ductile iron is formulated which includes heat flow, nucleation and growth of graphite nodules, and the segregation of Si. The model uses equilibrium temperatures given by the ternary Fe-C-Si equilibrium diagram. Using the mathematical model, cooling curves, nodule
count and nodular size distribution are determined as a function of position in the casting sample. The results are compared to measured temperatures, nodule count and nodule size in rod castings of 12.5, 20 and 43mm radius. There is good agreement between the calculated and measured values for the 43mm radius rod, and not quite good agreement for the rods of smaller radii. The changes in solidification predicted by the model when some solidification parameters are varied are consistent with experimental observations with the same variation in the parameters.Applied Science, Faculty of
Materials Engineering, Department of
Graduate
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Westphal, Mark Emil. "Fracture toughness of coral graphite cast iron." Thesis, Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/16892.
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Shah, Nishant Mayur. "Watson's Hotel: Celebrating the cast iron frame." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/31360.
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It is in human nature to preserve things and objects from the past, study, enjoy and cherish our history. This need to learn from and cherish the objects from the past has resulted in the development and evolution of spaces such as museums where people can come and see these objects, either to know or learn something or out of personal interest and curiosity.
Somewhere in all this, is architecture from the past taken for granted? A lot of the prominent historic buildings have been well preserved and are known to people. But at the same time there are numerous historic structures, story tellers from the past, being ignored and even trampled upon. Should we not look at these also as valuable objects that have to say so much about our social, cultural and technological past? Do they need a museum space as well? Can architecture be housed and preserved in a museum? Or maybe become a museum, displaying itself, allowing people to experience it from outside and within.
Watsonâ s Hotel is one such historical building that lies today unnoticed, uncared for, decaying and falling apart.
My thesis is an intervention into this urban situation. The goal of the design has not been just preservation but rather an elevation or celebration of the structure, bringing forth its true nature that lies in its structural framework, a cast iron grid of columns and beams. It aims to highlight this essential core of the building by revealing the grid in different spatial conditions. There is also a constant wish to tie the structure back to its surroundings, to bring back the dialogue that the building shared with its surroundings in the past. The structural framework is revealed and experienced in different spatial conditions achieved with the help of geometry, light and material, surfaces added in and around it, and the grid runs through all these elements bold, undisturbed and uninterrupted.Master of Architecture
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Sarnet, Jan. "Interaction between the alloying content, cast structure and forging process for large ingots /." Stockholm : Industrial Engineering and Management, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4072.
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Björkblad, Anders. "Fatigue Assessment of Cast Components : Influence of Cast Defects." Doctoral thesis, KTH, Lättkonstruktioner, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9133.
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This thesis is on the fatigue assessment of cast components with special attention to defects. The primary material in view is nodular cast iron, but also cast steel is considered. However, the fatigue behaviour is in principle valid for general use on other cast metals.The first two papers is about general cast material behaviour in fatigue loading. The materials considered are a high strength alloyed cast steel and a medium strength nodular cast iron. It is concluded that cast defects is the main fatigue initiation cause and it is only in exception that the fatigue life is not ruled by fracture mechanics. The third paper is a fracture mechanics evaluation of a nodular iron cast sleeve. The analysis of the component is based on crack initiation from cast defects and low-cycle fatigue. Fracture mechanics material parameters for Paris law, c and m, are extracted for the materials considered. In paper D design quality rules for nodular cast iron based on the Swedish standard SS 11 40 60 is presented. The quality rules regard cast defects in fatigue assessments and facilitate defect-based component design. In paper E, a finite element tool that is capable to predict and calculate 3D crack propagation for embedded cracks and defects is presented. The tool is an add-on for ANSYS finite element program. In paper F, closure equations for nodular cast iron are proposed in parallel to refined fracture mechanics material data. The paper includes crack propagation at different load ratios and in different microstructures.Summarized, the thesis composes a further development of the fatigue assessment of cast components. The central role of defects in fatigue is clarified and tools are provided for fracture mechanics evaluations of defects as well as for defect based design. The quality rules are also fit for application in manufacturing and for acceptance tests, hence covering the span from design to complete product.QC 20100712
Gjutdesign
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Vazehrad, Sadaf. "Shrinkage Porosity Characterization in Compacted Cast Iron Components." Thesis, KTH, Materialvetenskap, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-127261.
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Crepeau, Paul Noles. "Crack propagation in high chromium white cast iron." Thesis, Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/11182.
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Wetter, Pernilla, and Martin Kulig. "Hållfasthetsegenskaper i gjutjärn : tensile properties of cast iron." Thesis, Jönköping University, JTH, Mechanical Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-931.
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In the last few years people have become more and more aware of how humanity is affecting the climate. In the direction of reducing the greenhouse gases is to design engines with higher tensile properties and reduced weight, in order to achieve lower fuel consumption and cleaner fuel incineration in today's truck engines.
In order to achieve these requirements it’s necessary to increase the combustion pressure in the engine. This requires higher tensile properties and high thermal conductivity of the engine material. The department of Component Technology at the University of Jönköping in collaboration with Volvo Powertrain AB, Scania CV AB and DAROS Piston Rings AB has been commissioned to develop this material and to find knowledge of material properties used in truck engines and piston rings used for marine applications.
The purpose with this work is to analyze the tensile properties of a series of cast iron, cast under different metallurgical conditions.
Four different series of cast irons have been analyzed from four points of view, carbon concentration, nodularity, amount inoculation and cooling rate.
After the tensile test all specimen data was analyzed in a mathematic calculation program called Matlab 2006a. These results were plotted in different diagrams to show the relations between the variables.
A low carbon contents and high cooling rate result in high tensile properties and vice versa. Also, a high nodularity gives the same result, i.e. high ultimate tensile strength, yield strength and young’s modulus. The experiment which cover different amount of inoculation, shows that Superseed is the most efficient element to increased tensile properties followed by Fe-powder and Fe-C-powder.
Lamellar graphite iron has the highest thermal conductivity and vibration damping properties compared to compact graphite iron followed by nodular graphite iron. Researches show that the thermal conductivity increases with slow cooling rate, irrespective of graphite structure. When designing new diesel engines, high tensile properties as well as high thermal conductivity are wanted. Compact cast iron has a compromised quality of these requirements. Higher tensile properties are a higher priority than thermal conductivity when the casting cooling rate is chosen.
Mänskligheten har idag blivit allt mer medveten om vilken påverkan människan har på klimatet. Ett steg i att reducera växthusgaserna är att konstruera motorer med högre hållfasthet och reducerad vikt, detta för att uppnå lägre bränsleförbrukning och renare förbränning i dagens lastbilsmotorer.
För att uppnå dessa krav är en lösning att öka kompressionen i motorn. Detta medför högre hållfasthetskrav samt hög värmeledningsförmåga hos materialet i motorerna. Avdelningen för komponentteknologi på Tekniska högskolan i Jönköping har i samarbete med Volvo Powertrain AB, Scania CV AB och DAROS Piston Rings AB fått uppdraget att utveckla ett material med rätt mekaniska egenskaper för att passa i lastbilsmotorer och kolvringar i marina applikationer.
Målet med detta examensarbete är att analysera de mekaniska egenskaperna i en serie där gjutjärn gjutets under olika metallurgiska förhållanden.
Fyra olika serier av gjutjärn har analyserats med utgångspunkt av variation av kolhalt, nodularitet, mängd ympningsmedel samt svalningshastighet.
Efter dragning av samtliga prover analyserades mätdata i Matlab 2006a och resulterade i olika sambandsdiagram.
Låg kolhalt samt snabb avsvalning av gjutgodset ger höga hållfasthetsegenskaper och vice versa. En hög nodularitet ger höga hållfasthetsegenskaper gällande brottgrans, sträckgräns och elasticitetsmodulmodul. Från experimenten där olika ympningsmedels påverkan av hållfastheten, har kunnat konstateras att ympningsmedlet Superseed ger de högsta hållfasthetsegenskaperna följt av Fe-pulver och Fe-C-pulver.
Värmeledningsförmågan och dämpningsförmågan för vibrationer är bäst i lamellartad grafit följt av kompakt och nodulär grafit. Studier visar att värmeledningsförmågan ökar med långsam svalning, oavsett grafitstruktur. I dagens dieselmotorer eftersträvas både god hållfasthet och god värmeledningsförmåga. En kompromiss av dessa krav är gjutjärn med en kompakt grafitstruktur. Högre hållfasthet bör prioriteras före bättre värmeledningsförmåga när val av svalningshastighet för gjutgodset görs.
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Solem, Benjamin. "Dilatometry Study of a High-Chromium Cast Iron." Thesis, KTH, Hållfasthetslära (Avd.), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232528.
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High-chromium cast irons are used in certain applications where the demand on abrasion resistance is high. Such applications can be found in the milling industry and in pumps for transport of abrasive particles in liquid suspension. Soft annealed high-chromium cast iron containing 2.6 % C and 24.7 % Cr was supplied by Xylem Water Solutions, Sundbyberg, and investigated by dilatometry. The heat treatments were inspired by induction hardening procedures. The purpose of the investigation was to evaluate the effect of maximum temperature reached during heat treatment on the final length of the test specimen. The aim with this was to find the treatment yielding the maximum possible length which should be profitable to create desirable compressive stresses in the surface hardened area. The experimental results were used to create a finite element model in COMSOL Multiphysics accommodating for the maximum temperature, simulating the phase changes occurring in a geometry based on the experimental test specimen. The experimental results did not reveal any clear correlation between the maximum temperature and the final length change. The hardness, however, increased with the increasing temperature in the treatment interval 900-1150 °C. The, by light optical microscopy, observed amount of secondary precipitated carbides decreased with increasing temperature. Martensite transformation was also affected; the transformation temperature decreased for increased treatment temperatures. From dilatometry it was also seen that the thermal strains were greatly affected by the direction of which the material was cut from the original cast material. Samples taken perpendicular to the mainly investigated direction showed lower coefficients of thermal expansion and the final strain was clearly positive compared to the slightly negative values found for the main direction. This phenomenon could possibly be explained by different macrostructures created during solidification of the melt causing anisotropy in the eutectic. The implementation in COMSOL by describing the phase transformation as ordinary differential equations did show partially good results in the simulation of thermal expansion. The difference in original material is noticeable in the dilatometry and the simulated martensite transformation deviates from the experimental results. The model needs to be validated against new intermediate test temperatures and the martensite transformation kinetics must be investigated further to yield better results to be able to combine the phase transformations with mechanical calculations.
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Lukhi, Mehul. "Micromechanical Simulation of Fatigue in Nodular Cast Iron." Technische Universität Bergakademie Freiberg, 2020. https://tubaf.qucosa.de/id/qucosa%3A72791.
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In the present thesis, fatigue behavior of nodular cast iron (NCI) is investigated using micromechanical simulations. An elastic-plastic porous material experiences an increase in a void volume fraction with each cycle of loading. This is called void ratchetting. The hypothesis of this thesis is to explain the fatigue failure of NCI using void ratchetting mechanism. The strain-life, stress-life, notch support effect, and fatigue crack growth are studied using the micromechanical simulations. In all these studies, matrix material is defined as an elastic-plastic with isotropic/kinematic hardening. No damage law is used to define material degradation. The axisymmetric cell model is developed to study strain-life and stress-life approaches for fatigue. The cell model is subjected to cyclic loading and cycle by cycle simulations are carried out until failure. The failure of the cell model is defined based on the drop in the macroscopic response of the cell model. The notch support effect is investigated using a 2D plane strain model within stress-life concept. From the simulation results, strain-life and stress-life curves are extracted, and they are in qualitative and quantitative agreement with experimental data collected from literature. The fatigue crack growth is studied using a micromechanical cell model under small scale yielding conditions. The graphite particles are considered as voids, and they are resolved discretely in fracture process zone. The region outside of the fracture process zone is considered as a homogenized medium. When positive alternating loads are applied, ligaments in the fracture process zone show ratchetting behavior, which is responsible for an effective fatigue crack growth. This mechanism is relevant for the fatigue crack growth in NCI. The 2D plane strain boundary layer model is able to predict the effect of load ratio on threshold for the fatigue crack growth and the fatigue crack growth rate. The fatigue crack growth rate curves obtained from the simulations are compared with experimental data. It is essential to note that the void ratchetting (plastic collapse of the intervoid ligaments) is a crucial mechanism in NCI and more focus should be given to this mechanism as it is simple to implement and gives satisfying simulation results.
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Hernando, Juan Carlos. "Morphological characterization of primary austenite in cast iron." Licentiate thesis, Tekniska Högskolan, Högskolan i Jönköping, JTH, Material och tillverkning, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-35585.
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Automotive industry products portfolio includes a wide variety of complex‐shaped cast iron products, such as truck engine components, that need to withstand a constant trend of higher demands, especially urged by stricter environmental regulations on emissions. Combined with this continued demand on properties improvement, cast iron industry faces a process problem related to the lack of understanding of solidification and mechanisms behind defect formation. Casting products are highly affected by the product design and the manufacturing method itself, which governs the final microstructure and hence the final mechanical properties. Wall thickness of the moulding material strongly influences the solidification time, varying the microstructural coarseness, resulting in a component with different properties depending on the local shape of the casting. The main objective of this work is the characterization of the primary austenite microstructure and its coarsening process, which has been poorly documented in cast iron literature, to allow the prediction and control of these microstructural features present in the casting. The microstructural evolution of the primary austenite in hypoeutectic lamellar graphite iron (LGI) is studied under isothermal coarsening conditions. The dendritic microstructure suffered major morphological changes that included dendrite fragmentation, globularization, and coalescence. Empirical relations based on morphological parameters are introduced to predict the microstructural evolution of primary austenite. A novel technique for colour‐etching and semi‐automatic image analysis for the characterization of quenched dendritic microstructures in cast iron is presented. A new experimental technique for production of graphitic iron with varying nodularity is presented as a solution to control the production of compacted (CGI) and spheroidal graphite iron (SGI) under laboratory conditions. The nodularity evolution is controlled as a function of the holding time and the residual Mg, allowing the study of the primary solidification and primary microstructures of hypoeutectic CGI and SGI in future investigations.
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Armitage, Kelly, and n/a. "Laser assisted machining of high chromium white cast-iron." Swinburne University of Technology, 2006. http://adt.lib.swin.edu.au./public/adt-VSWT20070214.155302.
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Laser-assisted machining has been considered as an alternative for difficult-to-machine
materials such as metallic alloys and ceramics. Machining of some materials such as
high chromium alloys and high strength steels is still a delicate and challenging task.
Conventional machines or computer numerical control (CNC) machines and cutting
tools cannot adapt easily to such materials and induce very high costs for operations of
rough machining or finishing. If laser-assisted machining can be implemented
successfully for such materials, it will offer several advantages over the traditional
methods including longer tool life, shorter machining time and reduced overall costs.
This thesis presents the results of the research conducted on laser assisted machining of
hard to wear materials used in making heavy duty mineral processing equipment for the
mining industry. Experimental set up using a high power Nd:YAG laser beam attached
to a lathe has been developed to machine these materials using cubic boron nitride
(CBN) based cutting tools. The laser beam was positioned so that it was heating a point
on the surface of the workpiece directly before it passed under the cutting tool. Cutting
forces were measured during laser assisted machining and were compared to those
measured during conventional machining.
Results from the experiments show that with the right cutting parameters and laser beam
position, laser assisted machining results in a reduction in cutting forces compared to
conventional machining.
A mathematical thermal model was used to predict temperatures within the workpiece at
depths under the laser beam spot. The model was used to determine the effect of
various cutting and laser parameters on the temperature profile within the workpiece.
This study shows that laser assisted machining of hard to wear materials such as high
chromium white cast iron shows potential as a possible economical alternative to
conventional machining methods. Further research is needed before it can be
introduced in industry as an alternative to conventional machining.
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Armitage, Kelly. "Laser assisted machining of high chromium white cast-iron." Australasian Digital Thesis Program, 2006. http://adt.lib.swin.edu.au/public/adt-VSWT20070214.155302/index.html.
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Thesis (MEng) - Swinburne University of Technology, Industrial Research Institute Swinburne - 2006.A thesis submitted in fulfillment of the requirement for the degree of Master of Engineering by Research, Industrial Research Institute Swinburne, Faculty of Engineering and Industrial Sciences, Swinburne University of Technology - 2006. Typescript. Includes bibliographical references (p. 113-116).
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Sidhu, Mandeep Singh. "Liquid Aluminium Corrosion Characteristics of Cast Iron and Steel." Thesis, University of Canterbury. Mechanical Engineering, 2012. http://hdl.handle.net/10092/7013.
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Cast iron and steel alloys are commonly used for tooling and structural components in Al production, Al die-casting and the aluminizing industry due to their favourable properties including high strength, good formability and low cost. However, the iquid Al corrosion of these materials is one of the crucial concerns in maintaining the efficient production. Al is produced by the electrolytic smelting of alumina. Cast iron and/or cast steel pipes - commonly known as „tapping pipes‟ - are used to extract the liquid Al produced by smelting. Tapping pipes mainly degrade by material loss because liquid Al reacts with nearly all metals. Failure of tapping pipes is a significant contributor to the maintenance expenses; therefore, the primary aim of this research is to develop a material to enhance the life time of tapping pipes. Various test methods were developed in order to examine the effect of molten Al
environment on cast iron and steel alloys. The corrosion resistance of these alloys was determined under different conditions of Al flow and temperature. The intermetallic compounds formed by exposing the ferrous to liquid Al were characterized using the Energy Dispersive X-ray Spectroscopy (EDS) and Electron Back Scatter Diffraction (EBSD) techniques. The formation, growth and nature of reaction products were revealed to establish a link to the liquid Al corrosion resistance. A relationship between the chemical composition and liquid Al corrosion resistance of cast irons could not established in the past. In the present work, the corrosion rate was found to depend upon the graphite morphology and fraction of each Fe-C phase of cast
iron matrix, which can be controlled by selecting the chemical composition. Moreover, present research suggested the guidelines for producing a cast iron with enhanced liquid
Al corrosion resistance. The presence of C-rich phases, graphite flakes and cementite was found to be effective in enhancing the liquid Al corrosion resistance of gray cast
irons. Conversely, a higher Si content was found to enhance the susceptibility of cast irons to liquid Al corrosion.
The corrosion mechanisms for ferrous alloys in liquid Al are not fully understood. Thus the subsequent analysis of the dissolution data was supported by investigating the
reaction products formed between Al and substrate materials. In addition to commonly existent ε-Fe2Al5 and ζ-FeAl3 phases, the formation of Al4C3 and κ-Fe3AlC compounds was confirmed for the first time in the intermetallic layers of ferrous alloys. The Fe3Si phase in the intermetallic layers of high Si cast irons was found, which was believed to facilitate the high corrosion rates of high Si cast irons. Moreover, the mechanism by which C in Fe-substrates affects the liquid Al corrosion resistance can be better understood given the present work.
Furthermore, the analysis presented here gives an understanding of the nature, growth and dissolution of intermetallic compounds in several cast iron alloys. Higher Si
additions to cast irons played an important role in molten metal corrosion by accelerating the material loss and changing the nature of intermetallic layers. The results of this study
clearly indicated that the dissolution and the growth of intermetallic compounds are interrelated and the dissolution and/or spallation of the intermetallic layers may be the
primary mode of liquid Al corrosion of ferrous alloys.
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Andersson, Sofia. "Study of Dross in Ductile Cast Iron Main Shafts." Thesis, Karlstads universitet, Fakulteten för hälsa, natur- och teknikvetenskap (from 2013), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kau:diva-37148.
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The study of dross in ductile cast iron main shafts was performed at Global Castings Guldsmedshyttan AB and presented in this master thesis. The purpose of the study was to obtain answers to why dross defects were present in some of the foundry's casted main shafts, with the main problem located at the flange of the shaft. The chemical composition of the dross formations and which steps in the casting process that increased the dross formation were of interest. The study only included dross in main shafts manufactured at Global Castings Guldsmedshyttan AB. Dross particles form when elements such as Mg, Ca, Si and Mn react with O. These elements, which are highly reactive to O, are used in ductile cast irons to achieve the spheroidal graphite nodules that regulate the cast materials ductile properties. If a higher amount of dross particles has formed, the particles will start to cluster, resulting in a growing dross formation. Dross formations works as surface crack initiation points and reduces the castings fatigue strength and ductility. During the study it was seen that the cause of dross formations is a combination of many parameters increasing the melts exposure to O resulting in dross defects. The dross formations could be connected to worn out ladles, low melt temperatures, incorrect additions of Mg treatment, lack of an extra slag removal station and finally turbulence as the melt were poured into the mould. At Global Castings Guldsmedshyttan AB a greater part of the main shafts containing dross defects were a result of worn out ladles and low melt temperatures. The types of dross found in the main shaft material were mainly Mg, Ca, Si and Al which had reacted with O. S bonded with Mg and Ca was also detected in the dross formations. It was shown that the dross particles could be derived from charge material, Mg treatment and inoculation. To avoid dross defects the first step would be to set up an extra slag station, shorten the interval of maintenance of the ladles and to better adjust the melt temperature to the condition of the specific ladle. To minimize dross due to excess Mg a better controlled process would be recommended with an increased number of monitored manufacturing parameters.Studien av dross i axlar tillverkade av segjärn gjordes hos Global Castings Guldsmedshyttan AB och presenteras i denna examensrapport. Syftet med studien var att hitta anledningar till varför drossdefekter bildas i flänsen på vissa av gjuteriets tillverkade axlar. Drossens kemiska komposition likväl de steg i tillverkningsprocessen som inverkade på drossbildning var av intresse. Studien inkluderade endast drossdefekter i axlar tillverkade av Global Castings Guldsmedshyttan AB. Drosspartiklas bildas när till exempel Mg, Ca, Si och Mg reagerar med O. Dessa ämnen, vilka är väldigt reaktiva med syre, används vid framställning av segjärn för att de sfäriska grafitnodulerna som starkt reglerar materialets duktila egenskaper ska bildas. Ett större antal drosspartiklar i en smälta leder till kluster av dross vilka växer i takt med att nya partiklar bildas. Dross fungerar som sprickinitieringspunkter i gjutgodsytor och reducerar godsets utmattningshållfasthet och duktilitet. Under studien kunde det ses att dross bildas på grund av en kombination av parametrar som ökar smältans exponering av syre vilket resulterar i drossdefekter. Drossdefekter kunde kopplas till slitna skänkar, låga smälttemperaturer, felaktig mängd magnesiumbehandling, brist på en extra slaggstation och slutligen turbulens när smätan hälls i formen. Hos Global Castings Guldsmedshyttan AB är en stor del av axlarna med drossdefekter ett resultat av framför allt slitna skänkar och låga smälttemperaturer. Vid analys sågs det att ett antal olika typer av drosspartiklar kan bildas i det duktila gjutjärn som används till axlarna; främst Mg, Ca, Si och Al som reagerat med O. Mg och Ca som bundit med S kunde också hittas i vissa av de studerade drossformationerna. Det kunde visas att den kemiska kompositionen i drosspartiklarna var härrörande från grundmaterialet, magnesiumbehandlingen och ympmedlet. Ett första steg Global Castings Guldsmedshyttan AB skulle kunna ta för att undvika drossdefekter är att ha en extra slaggstation, införa tätare underhåll av skänkarna och bättre anpassa smälttemperaturen till skicket på den specifika skänken. För att minimera dross som bildats på grund av ett överskott av Mg skulle en mer kontrollerad process rekommenderas med ett ökat antal bevakade tillverkningsparametrar.
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O'Shea, Phillipa Jane. "Failure mechanisms for small diameter cast iron water pipes." Thesis, University of Southampton, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326519.
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Franklin, Steven E. "A study of graphite morphology control in cast iron." Thesis, Loughborough University, 1986. https://dspace.lboro.ac.uk/2134/32998.
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The objectives of the research project were to gain a deeper understanding of the factors influencing the graphite morphology in cast iron; particularly the role of different solute elements in relation to the industrial manufacture of compacted graphite iron. A number of melt treatment processes were assessed for their abilities to produce low nodularity compacted graphite microstructures over a range of casting section thicknesses. In this respect, the magnesium-titanium method was found to be superior to treatment using cerium Mischmetall and calcium additives; and very promising results were obtained with methods using zirconium as a major constituent of the treatment alloy. Scanning electron microscopy, secondary ion mass spectrometry and X-ray microanalysis were used to study the structural characteristics of different cast iron microstructures and the elemental distributions of important solutes between the phases. This information was used to clarify the role of the main solute elements in graphite morphology control and to assess current graphite growth theories.
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Lundberg, Mattias. "Residual Stresses and Fatigue of Shot Peened Cast Iron." Licentiate thesis, Linköpings universitet, Konstruktionsmaterial, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-99842.
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The complex geometry of cylinder head in heavy-duty diesel engine makes grey cast iron or compact graphite iron a perfect material choice due to its castability, thermal conductivity and damping capacity. To increase the efficiency of the engine, the fatigue property of the material needs to be improved. Shot peening is often used to increase the fatigue strength of components. The benefits are associated with the compressive stresses induced and with surface hardening. In this research project, these effects on grey and compact iron have been analyzed for different shot peening parameters using XRD, SEM and fatigue testing methods. The ultimate aim of the project is to increase the fatigue strength of cast irons by optimization of residual stresses. The XRD measurements and SEM examinations revealed that the shot peening parameters including shot size and peening intensity had significant influences on the resulted residual stresses and strain hardening while changing the coverage made little difference. Also differences in the peening results between the two materials were observed, which were ascribed to an effect of the different graphite morphology. Nevertheless, a residual stress profile similar to the one general considered to improve the fatigue strength in steels could be obtained in both grey and compact iron after shot peening. The axial fatigue testing with R=-1 on the grey iron showed that peening using large shot size and high peening intensity (heavy shot peening) resulted in a fatigue strength reduction of 15-20% in comparison with the mechanically polished surface. The negative effects are likely related to surface damage and relatively high tensile residual stresses in subsurface induced by the heavy peening. Grey cast iron has low ductility in tension and therefore tensile residual stresses may promote multiple cracking and crack networking during cyclic loading. Shot peening using much smaller shots and lower intensity (gentle shot peening) which resulted in a much smaller residual stress field gave no significant changes in fatigue strength. However, a short time annealing at 285°C of specimens being gently shot peened increased the fatigue strength roughly by 10%. The improvement could be an effect of precipitates formed due to the heat treatment, which lock the dislocation movement under cyclic loading.
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Elwell, David W. J. "Toughness and abrasion resistance of high alloy cast iron." Thesis, Aston University, 1986. http://publications.aston.ac.uk/11866/.
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Castillo-Bozzo, Ricardo N. "A fracture mechanics study of flake graphite cast iron." Thesis, Imperial College London, 1985. http://hdl.handle.net/10044/1/37651.
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Argo, Donald. "Microstructural transitions in directionally solidified graphitic cast irons." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=65926.
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Turrell, Michael Bernard. "A study of corrosion and iron pick-up in cast iron water supply pipes." Thesis, University of Hertfordshire, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303423.
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Kaviani, Saeid. "Processing, structure and properties of ordered iron-transition metal aluminides." Thesis, University of Sheffield, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286875.
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Zambrano, Habib. "Fatigue Assessment of Notches and Cracks in Ductile Cast Iron." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for produktutvikling og materialer, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-14632.
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The steadily increasing use of ductile cast iron and the necessity for building larger cast components present new challenges to the designers. In despite of large cast components are designed adhered to standards, unexpected failure sometime occurs. One reason is the inevitable manufacturing defects containing within the cast components that behave like cracks under cyclic loading. In addition the probability of a large defect to be situated at a critical region of the component increases with the size. Another reason is the effect of geometric discontinuities such as holes, threads and fillets, which are part unavoidable of the designs. These discontinuities that are usually called notches disturb the stress field and cause high local stress concentration. Thus dealing with these severe stress risers (defects and notches) is not an easy task. Therefore most designers resort to use very high and unnecessary safety factors.
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Rolley, Anne-Maree. "Cast iron and making fiction : a novel and critical essay /." [St. Lucia, Qld.], 2004. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe19339.pdf.
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Diószegi, Attila. "On microstructure formation and mechanical properties in grey cast iron /." Jönköping, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/tek871s.pdf.
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Laplante, Michael H. "Cast iron versus creativity: fostering balanced thinking in military professionals." Thesis, Monterey, California: Naval Postgraduate School, 2015. http://hdl.handle.net/10945/45885.
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Approved for public release; distribution is unlimitedThis research explores how the framing of tasks affects an individual’s psychological employment of thinking-style balance in performing those tasks. The methodology utilizes multivariant experimentation with military officers. The research analyzes the impact of how a commander frames a problem to a subordinate. More specifically, the work seeks to parse the effect of linear (analytical) framing, nonlinear (balanced) framing, or no additional frame (control). There were six key findings: military decision makers have a baseline linear thinking bias; a majority of the participants fell below the threshold for being moderately versatile thinkers; American participants had a stronger baseline linear bias than international participants; the impact of problem framing on overall thinking style was minimal; the linear treatment group experienced significantly lower emotional thinking scores; and the linear treatment group took significantly longer to complete the experiment. It was concluded that military decision makers have a strong linear bias that is not easily influenced by problem framing. It was also concluded that linear framing has a significant impact on decision-making time and emotional thinking. In an effort to reduce the military decision maker linear bias, it is recommended that professional military education include a significant increase in nonlinear thought processes, such as design thinking. It is also recommended that incentive structures be updated to create and promote an organizational culture that supports a linear/nonlinear balanced thinking approach to problem solving.
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Green, Fahami Annan, and Felix Göttfert. "Aspects of gating system improvement in a cast iron foundry." Thesis, KTH, Materialvetenskap, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298424.
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The gating system transfers the iron melt from the ladle to the void in the casting mould. The gating systems dimensions and designs are crucial for the success of a casting and a poor gating system is a leading cause of scraps. The main goal of this thesis is to improve the pouring basins and sprues at Norrlandsgjuteriet, an iron foundry located in northern Sweden. The step in the offset step basin and other variables that affect the gating system is explained, investigated and simulated in MAGMASOFT. Furthermore, put to practice at Norrlandsgjuteriet. Adding a step in the offset basin fills a very important function in the system, fending off air bubbles that might enter the mould and reduce the horizontal velocity of the melt. The basin’s height and the sprue’s cross-section control the casting time and simulations conducted in this thesis show that a step can create a beneficial rounding to the flow over the step, creating a laminar flow of the melt, down the sprue contributing to a lower casting time. A narrower sprue is better, in which the melt’s surface tension is maintained, creating an oxide pipe-layer that protects the flowing melt entering the mould and from entrainment defects. The results show that replacing the offset basins used today with offset step basins, which are 30% smaller in volume, together with a tighter sprue will not only reduce the annual material consumption by 1% or 13 000 kg but more importantly increase the quality of the casting. This due to lower melt velocity, a more homogenous temperature, better flow in the basin with less air entering the mould.Ingjutsystemet transporterar det smälta järnet från skänken till gjutformens hålrum. Ingjutsystemets dimensioner och utformning är avgörande för en lyckad gjutning och ett dåligt utformat ingjutsystem är den främsta orsaken till kassationer. Syftet med denna rapport är att förbättra gjutskålarna samt nedlopp som Norrlandsgjuteriet, ett järngjuteri i norra Sverige, använder. Steget i den förskjutna gjutskålen och andra variabler som påverkar ingjutsystemet förklaras, undersöks och simuleras i MAGMASOFT. Utöver detta testas det även praktiskt hos Norrlandsgjuteriet. Att lägga till ett steg i gjutskålen fyller en väldigt viktig funktion i ingjutssystemet i och med att luftbubblor avvärjs från att följa med in i formen samt minskar även smältans horisontella hastighet. Gjutskålens höjd och nedloppets tvärsnittsarea avgör gjuttiden och simulationer som genomfördes visade också att stegets rundning i gjutskålen skapar ett fördelaktigt flöde över steget vilket skapar ett laminärt flöde ner i nedloppet vilket samtidigt bidrar till en minskad gjuttid. Ju smalare nedlopp desto bättre upprätthålls smältans ytspänning vilket skapar ett oxidskikt som skyddar den flytande smältan, som ska fylla formen, från inblandning av luft och oxider. Resultaten visar att genom att byta ut de förskjutna gjutskålarna som används idag med förskjutna steggjutskålar, som är 30% mindre i volym, tillsammans med en smalare nedlopp så kommer inte bara den årliga materialförbrukningen att minska med 1% eller 13 000 kg men ännu viktigare att höja kvaliteten på de gjutna detaljerna. Detta på grund av lägre smälthastighet, en mer homogen temperatur, bättre flöde i gjutskålen samt mindre luft som tränger in i formen.
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Conlin, Roger Michael. "The application of fracture mechanics to grey cast iron pipework." Thesis, Imperial College London, 1991. http://hdl.handle.net/10044/1/8279.
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Tang, Jiaming. "Impact of Gray Cast Iron Microstructure on Brake Pad Stiction." OpenSIUC, 2021. https://opensiuc.lib.siu.edu/theses/2886.
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This research study talks about the possible influence of gray cast iron microstructure on the corrosion properties of the brake rotor and the effect of stiction. Three Gray cast iron rotors with fully pearlitic microstructure and below 5% volume content of ferrite were studied in this research to understand their microstructural influence over corrosion. The selected gray cast iron rotors were friction tested against a 2009 Original Equipment Manufacturer (OEM) Ford F150 brake pad using scaled-down SAE J2522 standard test. Tested samples were later subjected to GMW16696 standard test, to identify the breakaway forces indirectly defining the corrosion resistance of the friction material used. The results show that the degree of corrosion and breakaway forces observed are greatly influenced by the graphite content quantified from quantitative analysis techniques adopted. Rotor with higher graphite content observed higher breakaway force and higher oxygen content compared to the other two studied rotors. Higher graphite content is considered to provide more cathodes, it accelerates the corrosion of the iron element in the rotor. There is no reliable correlation between the pearlite and ferrite of the gray cast iron rotor stiction force. The poor correlation between stiction force and microstructure also shows that the size of stiction force is not determined by a single factor.
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Gieseke, Brian G. "Observations on the fracture of hypoeutectic, high chromium white cast irons." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/19967.
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Orrock, Clive Martin. "The microstructure and properties of equiatomic iron-cobalt magnetic alloys with alloying additions." Thesis, Imperial College London, 1986. http://hdl.handle.net/10044/1/38127.
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Ferranti, Louis Jr. "Mechanochemical Reactions and Strengthening in Epoxy-Cast Aluminum Iron-Oxide Mixtures." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/19722.
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This investigation is focused on the understanding of mechanical and chemical reaction behaviors of stoichiometric mixtures of nano- and micro-scale aluminum and hematite (Fe2O3) powders dispersed in epoxy. Epoxy-cast Al+Fe2O3 thermite composites are an example of a structural energetic material that can simultaneously release energy while providing structural strength. The structural and energetic response of this material system is investigated by characterizing the mechanical behavior under high-strain rate and shock loading conditions. The mechanical response and reaction behavior are closely interlinked through deformation characteristics. It is, therefore, desirable to understand the deformation behavior up to and beyond failure and establish the necessary stress and strain states required for initiating chemical reactions.
The composite s behavior has been altered by changing two main processing parameters; the reactants particle size and the relative volume fraction of the epoxy matrix. This study also establishes processing techniques necessary for incorporating nanometric-scale reactants into energetic material systems. The mechanochemical behavior of epoxy-cast Al+Fe2O3 composites and the influence of epoxy volume fraction have been evaluated for a variety of loading conditions over a broad range of strain rates, which include low-strain rate or quasistatic loading experiments (10-4 to 10-2 1/s), medium-strain rate Charpy and Taylor impacts (103 to 104 1/s), and high-strain rate parallel-plate impacts (105 to 106 1/s). In general, structural strength and toughness have been observed to improve as the volume fraction of epoxy decreases, regardless of the loading strain rate regime explored. Hugoniot experiments show damage occurring at approximately the same critical impact stress for compositions prepared with significantly different volume fractions of the epoxy binder phase. Additionally, Taylor impact experiments have indicated evidence for strain-induced chemical reactions, which subject the composite to large shear accompanied by temperature increase and associated softening, preceding these reactions.
Overall, the work aims to establish an understanding of the microstructural influence on mechanical behavior and chemical reactivity exhibited by epoxy-cast Al+Fe2O3 materials when exposed to high stress and high-strain loading conditions. The understanding of fundamental aspects and the results of impact experiment measurements provide information needed for the design of structural energetic materials.
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Pustal, Björn [Verfasser]. "Solidification modeling of austenitic cast iron : a holistic approach / Björn Pustal." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1016392257/34.
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Taivalkoski, Olivia. "Evaluation of material properties after laser welding on ductile cast iron." Thesis, KTH, Materialvetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-254653.
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Scania wants to lower the weight of their trucks, including the goal to reduce the carbon dioxide emissions, and one way to do that is to use laser welding instead of fastenings.This bachelor thesis work is about laser welding of ductile cast iron, or spheroidal graphite cast iron or nodular cast iron, to QT-steels and case hardening steel and evaluation of the mechanical properties of the weld. Also laser welding of cast steel to the same two materials are being evaluated in this work. Tests are done to evaluate the effect on the material from laser welding. The tests are tensile tests and Vickers hardness test; both across and along the weld and in some areas of interest. EDS (Energy Dispersive X-Ray Spectroscopy) is used to analyze the composition in the weld and light optical microscope is used to look at the fusion zone (FZ) and the heat affected zone (HAZ). The results shows that the hardness is high in the heat affected zone due to the formation of martensite and that the materials mix more towards the root of the weld. The materials also mix more if the weld depth is deeper. The width of the heat affected zone seems to be longer if the heat input is higher. It is also clear that welding of cast steel is less complicated than the welding of ductile cast iron. That is because ductile cast iron gets a hard and brittle heat affected zone (HAZ) while the cast steel does not. The cast steel can also be welded without filler wire without getting to hard or to brittle. If laser welding is to be used in the future the component should be constructed in such a way that the fusion zone is not carrying the main load. Tests on fatigue strength should also first be done on a finished component as it cannot be tested on the samples in this work. This work was conducted at Scania AB and the royal institute of technology, KTH, in Sweden.Scania vill sänka vikten på sina lastbilar, bland annat för att minska utsläppen av koldioxid, och ett sätt att göra det är att lasersvetsa istället för att använda bultar. Detta kandidatexamensarbete handlar om lasersvetsning av segjärn, eller nodulärt gjutjärn som det också kallas, till seghärdningsstål och sätthärdningsstål samt utvärdering av svetsens mekaniska egenskaper. Även lasersvetsning av gjutstål till samma stålsorter som ovan utvärderas i detta arbete.Tester görs för att utvärdera effekten på materialet från lasersvetsningen. Testerna är dragprov och Vickers hårdhetstestning; både tvärs över och längs med svetsen samt även i vissa områden av särskilt intresse. EDS (Energy Dispersive X-Ray Spectroscopy) används för att analysera sammansättningen i svetsen och ljusoptiskt mikroskop används för att se svetsgodset och den värmepåverkade zonen. Resultaten visar att hårdheten går upp i den värmepåverkade zonen på grund av martensit bildning och att materialen blandar sig mer närmare svetsroten. Materialen blandar sig också mer om svetsdjupet är djupare. Den värmepåverkade zonens bredd verkar vara större om sträckenergin är hög. Det står också klart att svetsning av gjutstål är mindre komplicerat än svetsning av segjärn eftersom segjärnet får en hög hårdhet i den värmepåverkade zonen medan det inte alls blir så för gjutstålet. Gjutstålet kunde också svetsas utan tillsatsmaterial utan att få ett för hårt eller sprött svetsgods. Om man vill använda lasersvetsning i framtiden ska komponenter konstrueras så att svetsen inte bär huvudvikten eftersom resultatet visar att svetsgodset får lägre brottgräns. Utmattningstester borde också göras på en färdig komponent eftersom det inte kan testas på proven från det här arbetet. Detta arbete utfördes på Scania AB och Kungliga Tekniska Högskolan, KTH, i Sverige.
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MELLO, CARLOS ALBERTO TORRES DE. "FATIGUE LIFE OF A FERRITIC NODULAR CAST IRON OF DIFFERENT MICROSTRUCTURES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3721@1.
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Esta pesquisa teve como objetivos promover variações
microestruturais em um ferro fundido nodular ferrítico tipo
ASTM A536 60-40-18, pelo do uso de resfriadores durante a
solidificação do material e pela adoção de tratamentos
térmicos pós-fundição, bem como avaliar a influência de
tais variações microestruturais sobre as propriedades
mecânicas e vida em fadiga do material.
Inicialmente, amostras do material foram fundidas em areia
com e sem o uso de resfriadores. Após a fundição, algumas
amostras de ambas as condições de resfriamento sofreram
normalização, enquanto outras foram recozidas, perfazendo
seis diferentes condições microestruturais: sem resfriador
bruta de fundição (SRB); sem resfriador normalizada (SRN);
sem resfriador recozida (SRR); com resfriador bruta de
fundição (CRB); com resfriador normalizada (CRN) e com
resfriador recozida (CRR).
Em seqüência, corpos de prova de todas as condições
mencionadas acima foram ensaiados em tração e,
posteriormente, sofreram análises metalográficas
qualitativas e quantitativas. Dando continuação a etapa
experimental, levantaramse as curvas tensão versus número
de ciclos para a falha das condições microestruturais SRB,
SRR, CRB e CRR, por meio de ensaios de fadiga em flexão
rotativa. A vida em fadiga do material também foi
relacionada com às características metalúrgicas de cada
condição.The objectives of the present work were to promote microstructural variations in an ASTM A 536 60-40-18 ferritic nodular cast iron, making use of cast coolers during and adopting heat treatments after casting, as well as to evaluate the influence of the microstructural variations on the mechanical properties and fatigue life of the material. Initially, samples of the material were cast in sand moulds with and without internal coolers. After casting, a number of samples in both cooling conditions were subjected to normalizing and annealing heat treatments and, therefore, six different microstructural conditions were obtained: as- cast without cooler (SRB), normalized without cooler (SRN), annealed without cooler (SRR), as-cast with cooler (CRB), normalized with cooler (CRN) and annealed with cooler (CRR). Tensile test were carried out on specimens representing the above mentioned conditions and their microstructures were analysed by qualitative and quantitative metallography. In the sequence of the experimental procedure, rotating bend fadigue test were performed in order to establish the stress-life curves for the SRB, SRR, CRB and CRR microstructural conditions. The fadigue life of the material was also related to the metallurgical characteristics of each condition. The metallographic analysis has indicated that the use of coolers increases the number of graphite nodules, reduces the graphite nodule size and otimizes the spherical morphology. However, these microstructural modifications seam to have no significant influence on the mechanical properties of the material. As to the effect of normalizing annealing, boht treatments not imply in significant changes in the mechanical properties of the as-cast conditions. Regarding the fadigue resistance of the material in the as-cast conditions, the CRB sample showed a longer fatigue life than the SRB samples and this performance under cyclic loading was attributed to the fact that the CRB condition is characterized by a higher number of graphite nodules of class VI. A comparison between the as-cast and annealed conditions indicated that the microstructural conditions SRR and CRR presented a lower fatigue resistance than the conditions SRB and CRB, respectively. This behaviour was associated with the microstructural features of the as-cast conditions, namely the smaller graphite nodule size, the higher microhardness of the matrix and the presence of the bull`s-eye structure. Finally, the experimental stress-life curves were modelled by means of Coffin-Manson law, which was considered efficient in the fadigue life data of ferritic nodular cast iron.
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Kambakas, Kyriakos. "Development of white cast iron matrix composites by sedimentation sand casting." Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/843688/.
Full textAbstract:
In the work that is described in this thesis we studied a new cast iron based composite material that was produced by a double casting technique using sedimentation sand casting. The material is based on the high Cr white cast irons (WCI) 15, 20 % Cr-Mo- LC and 25 % Cr matrixes, according to ASTM A532-75a and was designed to exceed the wear life of wear resistant materials that are used in cement, mining, coal extraction and chemical and process industries currently. The working region of the material extends to a depth of 5-8 mm below the surface and is an in situ and ex situ particle reinforced composite. WC particles of different sizes (1-3 and 3-5 mm) were selected as the ex situ reinforcements. Thus, the composite consisted of a WCI matrix, which was reinforced with WC and other transition metal carbide particles. A sand casting method was developed during which the WC particles were directed to a specific location in the ingot and were distributed uniformly in the near surface area of the composite (the working region of the material) during casting/solidification of the ingot. This ensured chemical bonding between the high Cr WCI and the particle reinforced composite (the working region) at a well defined interface parallel to the working surface. Solidification of the melt started from the WC particles around which three reaction zones were formed. Owing to partial dissolution of the WC particles and the resulting interdiffusion of elements such as W, Co, Fe, C and Cr, carbides containing Fe, Cr, W and Co were formed in the reaction zones. It is shown that current models for the interaction between a reinforcing particle and an advancing S/L interface in liquid route MMCs cannot describe the present case successfully because the solidification of the melt starts around the WC particles after the latter have settled in the near surface region of the casting. Two new approaches have been studied; in the first the WC particles travel through the iron melt and settle at the bottom of the mould and in the second WC particles settled at the bottom of the mould experience the forces of the liquid flow. The solidification paths of the three WCI matrixes and MMCs have been simulated with the Scheil-Gulliver model using the Thermo-Calc software for different iron based alloy systems, by changing the W, Cr and C concentrations. In the WCI, carbides solidify after the austenite. The increase in Cr from 14 to 25 wt. %, for fixed C (at 2, 2.5 or 3 wt. %), causes the stabilization of phases according to cementite M7C3 FCC (stable). Only for Cr up to 30 wt. % and C up to 2.5 wt. % the cementite is replaced by the BCC phase. The increase in C content from 2 to 3 wt. % for fixed Cr (at 14, 20 or 25 wt. %) has the same effect. In the MMC, the increase in W from 15 to 25 wt. % causes the stabilization of M6C. As the C increases from 2.5 to 6 wt. %, first the M7C3 is stabilised and for C > 4 wt. % the MC phase is favoured. The increase in Cr leads in the formation of the M23C6 while simultaneous increase in Cr and C promotes the M7C3 phase and restrains the formation of the M6C that resulted from the increase of W. Finally the simultaneous increase of C, W and Cr stabilize the MC phase for > 4 wt. % C. The wear of the new materials was evaluated both in an industrial scale and in the laboratory (pin-on-disc). Segments of an industrial pulverising ash mill used in the cement industry were manufactured using the casting method and materials developed in this thesis. The results showed an improvement in the wear life of the component of several times compared to the standard high Cr WCI material used by the same industry to date.
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Cornedi, Drew Jason. "The Densification of Historic Districts: Applying Metabolism to the Cast Iron." University of Cincinnati / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1353087757.
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Cornedi, Drew. "The Densification of Historic Districts: Applying Metabolism to the Cast Iron." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1393235792.
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Buchli, Marcelo. "Análise de manufatura e de produto para a utilização do ferro fundido austemperado ADI grau 3 em eixo comando de válvulas de motores Diesel." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/264964.
Full textAbstract:
Orientador: Jefferson de Oliveira GomesDissertação (mestrado profissional) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecânica
Made available in DSpace on 2018-08-17T00:45:15Z (GMT). No. of bitstreams: 1 Buchli_Marcelo_M.pdf: 3752727 bytes, checksum: 40d7b010cd2e281baaa3faf8554cb691 (MD5) Previous issue date: 2010
Resumo: Neste trabalho foi estudado o ferro fundido austemperado (ADI) grau 3 para substituir o aço forjado SAE 1045 temperado e revenido na aplicação do eixo comando de válvulas para motores Diesel. Na comparação dos materiais foram verificadas as propriedades mecânicas através de ensaios de laboratório e na literatura. A resistência ao desgaste foi a principal propriedade mecânica avaliada. Com o objetivo de se eliminar a operação de acabamento em retífica, especificada para os eixos comando de válvulas em aço forjado, o acabamento na usinagem de torneamento do ADI grau 3, no estado beneficiado, também foi analisado. O ADI grau3 atendeu à solicitação de desgaste quando comparado ao aço forjado e obteve um acabamento na operação de usinagem em torno, muito próximo ao acabamento do aço forjado na operação de retífica. Os resultados deste trabalho servem como base de estudo para o desenvolvimento e a fabricação de eixo comando de válvulas em ferro fundido austemperado grau 3 para motores Diesel
Abstract: The austempered ductile iron grade 3 was investigated as a substitute to SAE 1045 forged steel quenched & tempered in Diesel engines camshaft application. The mechanical properties for both materials were compared in laboratory tests and in the literature. The main mechanical property studied was the wear resistance. The microstructure, chemical composition was analyzed and correlated to camshaft requirements. The finishing turning machining characteristic of heated treated ADI grade 3 also was tested to verify the possibility of eliminating the grinding operation to SAE 1045 forged steel. As a conclusion of this study the ADI grade 3 complied with wear requirements when compared to forged steel and reached a finishing turning machining very close to grinding operation on forged steel. The results of this study can be used as basis to new development and production of diesel engines camshaft with austempered ductile iron
Mestrado
Materiais e Processos de Fabricação
Mestre em Engenharia Automobilistica
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Bobyliov, Konstantin. "Casting voids influence on spheroid graphite cast iron high-cycle fatigue strength." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2008. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2008~D_20081128_120950-42235.
Full textAbstract:
The influence of casting voids on spheroid cast iron cracking threshold is investigated. The experimental results and their analytical and numerical analysis basing on linear fracture mechanics is presented.Nagrinėjamas liejimo tuštumų poveikis stipriojo ketaus pleišėjimo slenksčiui. Pateikiami eksperimentiniai rezultatai ir jų analitinė bei skaitinė analizė, remiantis tiesine irimo mechanika.
Исследуется влияние литейных пустот на порог трещиностойкости чугуна с шаровидным графитом. Представлены результаты экспериментального исследования и их аналитический и численный анализ, опираясь на линейную механику разрушения.
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Adolfi, Sofia. "Slag inclusion formation during solidification of steel alloys and in cast iron." Licentiate thesis, Stockholm : Materialvetenskap, Kungliga Tekniska högskolan, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4371.
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