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PROGRESSIVE PRODUCTION PROCESSES AND SIMULATION OF STRUCTURES AND PROPERTIES OF SPHEROIDAL GRAPHITE CAST IRON
Musilová, Iveta ; Mores, Antonín (referee) ; Pacal, Bohumil (referee) ; Šenberger, Jaroslav (advisor)
The thesis is concerned with relationships between progressive technological processes of spheroidal graphite cast iron’s production and their structural properties. The aim of the work is to explain causal relationship between parameters of the proposed manufacturing technology of the iron type given (involving selected variants of modification and inoculation of melt and the parameters of melt crystallization, solidification and cooling down in a mould), their structure and even chemical heterogeneity of elements in this structure. For close specification of presented relationships three-dimensional model of spheroidal graphite growth was used, which was developed at the Brno University of Technology, Faculty of Mechanical Engineering. Its usability in praxis has been verified on the basisis of the application of this model on experimentally acquired data. The U GRAFIT 20 model of the authors Stránský and Million counting segregation in the frame of eutectic cell has not still been used for prediction of segregation in real condition in greater extent. On the basis of the above mentioned model microsegregation within “on average” of the cell has been discovered during experimental melts. Microsegregation has been described by segregation and heterogeneity indexes. Calculated values of segregation and heterogeneity indexes have been compared with experimentally verified values. On the basis of comparison of calculated and measured values the possibility of further usage of the mentioned model in praxis has been explored.
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Assembling the Technological Process for a Part of the Gearbox
Hoffmann, Jiří ; Osička, Karel (referee) ; Kalivoda, Milan (advisor)
The aim of my bachelor´s thesis is to create a technological process for manufacturing a gear housing component.. The chief output of my work is developing a technological process with the selection of appropriate tools for machining the casting. The thesis also deals with generating NC program, techno - economic comparisons, the design of worholding devices and recommends solutions of other identified issues.
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Manufacturing, structure and properties of cast iron with globular graphite produced on electric furnaces
Tvrdoň, Tomáš ; Pernica, Vítězslav (referee) ; Záděra, Antonín (advisor)
The diploma thesis deals with the technology of production of ductile iron with lower production costs. The thesis takes into account quality in terms of internal structure and mechanical properties. The thesis consists of two parts. The first part is about theoretical analysis of the topic of graphite cast irons with a more detailed discussion of the chemical composition, structure and properties of ductile iron. The experimental part deals with the production of ductile iron on electric arc and induction furnaces with different metall charging. Subsequently, the structures and mechanical properties of the ductile iron produced on these two melting aggregates are compared. An important part of this work is also an economic evaluation, where the proposed variants are compared in terms of metall charging and used melting aggregates.
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Influence of cement moulds on the structure of nodular iron castings
Stachovec, Ivo ; Šenberger, Jaroslav (referee) ; Rusín, Karel (advisor)
The object of the diploma thesis was to solve and to describe the influence of cement sands moulds on the structure of castings with cast iron LKG. The work was intent on watching the tendency of cement sands to the metal penetration of castings, rising of the compounds on the metal mould interface and liquid metal and accompanies elements on the shape of the graphite in the surface of casting. The study of this processes has a big theoretical and a practical meaning, for prevent and prediction of rising of the defects that are attached with unsuitable choice of sand.
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Structure and mechanical properties of thin wall nodular iron castings
Chýlková, Adéla ; Mores, Antonín (referee) ; Roučka, Jaromír (advisor)
The purpose of this final thesis is experimental verification of the influence of graphitic inoculants containing different amounts of trace elements on the structure, mechanical properties and internal homogeneity of thin-walled ductile iron casting. This thesis describes the issue with casting of thin-walled ductile iron. Two melts of thin-walled test plates with thickenesses of 3-, 5- and 8 mm were done in experimental part. A total of six types of inoculations with different content of trace elements were tested. Subsequently, an X-ray irradiation analysis was performed on the samples and hardness, tensile strength and ductility were evaluated. Futhermore, the amount of graphite in structure, graphite shape, graphite size, nodularity, graphite nodule count and volume phases of ferrite and perlite in matrix were analysed in thin-walled ductile cast iron by computer-based image analyzer. Finally, the measurement data were processed into tables and charts and conclusions were formulated. An X-ray analysis proved, that all thin-walled test plates containned shrinkage porosity. Furthemore it was confirmed, that content of manganese in inoculant increases tensile strength and hardness. Also content of zirconium in inoculant increases graphite nodule count.
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Structure and mechanical properties of thin wall nodular iron castings
Chýlková, Adéla ; Mores, Antonín (referee) ; Roučka, Jaromír (advisor)
The purpose of this final thesis is experimental verification of the influence of graphitic inoculants containing different amounts of trace elements on the structure, mechanical properties and internal homogeneity of thin-walled ductile iron casting. This thesis describes the issue with casting of thin-walled ductile iron. Two melts of thin-walled test plates with thickenesses of 3-, 5- and 8 mm were done in experimental part. A total of six types of inoculations with different content of trace elements were tested. Subsequently, an X-ray irradiation analysis was performed on the samples and hardness, tensile strength and ductility were evaluated. Futhermore, the amount of graphite in structure, graphite shape, graphite size, nodularity, graphite nodule count and volume phases of ferrite and perlite in matrix were analysed in thin-walled ductile cast iron by computer-based image analyzer. Finally, the measurement data were processed into tables and charts and conclusions were formulated. An X-ray analysis proved, that all thin-walled test plates containned shrinkage porosity. Furthemore it was confirmed, that content of manganese in inoculant increases tensile strength and hardness. Also content of zirconium in inoculant increases graphite nodule count.
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Manufacturing, structure and properties of cast iron with globular graphite produced on electric furnaces
Tvrdoň, Tomáš ; Pernica, Vítězslav (referee) ; Záděra, Antonín (advisor)
The diploma thesis deals with the technology of production of ductile iron with lower production costs. The thesis takes into account quality in terms of internal structure and mechanical properties. The thesis consists of two parts. The first part is about theoretical analysis of the topic of graphite cast irons with a more detailed discussion of the chemical composition, structure and properties of ductile iron. The experimental part deals with the production of ductile iron on electric arc and induction furnaces with different metall charging. Subsequently, the structures and mechanical properties of the ductile iron produced on these two melting aggregates are compared. An important part of this work is also an economic evaluation, where the proposed variants are compared in terms of metall charging and used melting aggregates.
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Production of LKG castings and cost comparison depending on the melting furnace
Exner, Zbyněk ; Šenberger, Jaroslav (referee) ; Záděra, Antonín (advisor)
This thesis is focused on technology of manufacturing ductile cast iron by using metal melted in cold blast cupola. The temperatue of cast iron melted in cupola furnace is often insufficient for subsequent metalurgicall processing of the cast iron, i.e. modification. Chemical heating could be used as an alternative for the needed increasement in temperatue of the melted metal before a modification. For the purposes of the experiment, a ladle for chemical heating was designed and manufactured within the diploma thesis. Furthermore, the work presents the results of two test melts, in which cast iron corresponding to EN-GJS-500-7 was produced after heat treatment. The thesis includes images of the structure of cast samples and samples even after heat treatment. Furthermore, the work presents an optimization solution for the charge comosition to the cupola furnace in order to reduce the phosphorus content. For the overall economic evaluation, the composition the charge comosition for the production of sferoidical graphite (SG) iron on the electric induction furnace was proposed and its costs were compared with the possibilities of SG iron production at the cupola furnace. Based on the determined costs of individual variants, the return on the transition from a cupola furnace to an electric induction furnace was calculated.
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Influence of sand size of core mixtures on surface quality of cast iron castings
Brůža, František ; Krutiš, Vladimír (referee) ; Záděra, Antonín (advisor)
The diploma project deals with the mechanisms of burn-on casting defects on castings made of spheroidal graphite cast iron. It discusses the elimination of their occurrence in the conditions of the German foundry MAT Ueckermünde by changing the granulometry of the core sand. Subsequently, the thesis deals with the influence of this change on the greensand. Furthermore, the thesis compares three refractory coatings supplied by the foundry. The coatings are compared both by laboratory measurements and by experimental tests during casting in conditions simulating the operation of this foundry. Finally, the individual tests are evaluated, including the effect of the individual measures in the case of their use in MAT Ueckermünde.
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