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Electric induction furnaces in foundries
Bruštík, Josef ; Kaňa, Václav (referee) ; Šenberger, Jaroslav (advisor)
The main aim of this Bachelor thesis is to create a technical summary on the topic of “The electric induction furnaces in foundries” and be more closely familiar with this issue. A division of furnaces and ways of melting by particular types of furnaces are briefly described. On the basis of gained knowledge, an evaluation of economic and technical advantages of these melting devices was performed and subsequently it is recommended for further usage in the foundries.
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Use of exothermic sleeves for aluminium alloy castings
Jakubec, Petr ; Martinák, Rostislav (referee) ; Kaňa, Václav (advisor)
This master's thesis deals with the influence of the exothermic riser sleeves on the solidification time of aluminum alloys. The thesis is divided into five parts. The first chapter describes solidification of cast alloys. The second chapter deals with the designing of risers. The third chapter is focused on the types of risers. The fourth chapter describes ways of intensification of risers and chemical composition of exothermic and insulating mixtures for production of riser sleeves. The main fifth chapter focuses on experimental measurements of temperatures and solidification time of aluminum alloy in castings, risers and exothermic and insulating riser sleeves.
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Effect of lead and antimony on the degradation of graphite shape in cast iron
Hlobil, Albert ; Kaňa, Václav (referee) ; Záděra, Antonín (advisor)
The bachelor thesis focuses on the effect of lead and antimony on the degradation of graphite in cast iron in relation to the lowered mechanical characteristics. This leads to the subsequent summary of the formation of degraded structures and unfavourable elements – the elements that are the cause of the formation. In the practical segment of the thesis, I will prove the effects of lead (or the combination of lead and antimony) on the degradation of graphite in cast iron with the focus lying at flake graphite. Furthermore, the thesis examines the mechanical characteristics and the attenuation of cast iron in relation to the formation of degraded graphite structures.
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Defects in steel castings
Jakubec, Petr ; Kaňa, Václav (referee) ; Pernica, Vítězslav (advisor)
This bachelor’s thesis deals with the problems of defects that occur in steel castings. First, the use of steel in the foundry industry and the development of classification of casting defects are described. Furthermore, it defines the term ‘casting defect’ and its division. The main part of the thesis focuses on the most frequent defects in steel castings. The aim of this literature search is to describe the casting defects and their causes and to present possible precautions against their rise. Possible ways of removing the casting defects are discussed as well as their repairs.
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Production of castings from Cu-Ni based alloys
Kelbl, Michal ; Kaňa, Václav (referee) ; Záděra, Antonín (advisor)
This master thesis is focused on melting of Cu-Ni based alloys and production of castings from these alloys. The theoretical part includes introduction of Cu-Ni based alloys and their properties and application. At the end of this part is production foundry technology of Cu-Ni alloys described. In the practical part two proposed melt controls for cupronickel (Cu-Ni) and for monel (Ni-Cu) have been performed. From these melts trial castings, castings of blades and bearings have been produced. The trial casting and the casting of bearing have been produced by using sand moulds and the casting of blade by using ceramic shell. According to internall quality of produced castings the performed melt controls have been evaluated. In addition to the internal quality of the castings, the chemical composition, microstructure and mechanical properties were evaluated.
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Research, Optimization and Starting the Production of Heavy High-Alloy Cast Irons
Kaňa, Václav ; Elbel, Tomáš (referee) ; Martínek, Ludvík (referee) ; Šenberger, Jaroslav (advisor)
The work is particularly aimed at metallurgical problems connected with manufacture of castings of weight about 1 up to 40 tons from high-alloy austenitic nickel cast irons also known under the trade name Ni-resist. The main aim is to check and complement the knowledge about manufacture of heavy castings from austenitic nickel cast irons in a field of control of tapping and casting temperature, carbon content control with regard to the prediction of eutectic composition and in a field of setting a suitable chemical composition of cast iron with regard to the formation of chunky graphite and stability of the austenitic matrix and further on also possibilities of cast iron filtration during pouring the castings. Based on done experiments the formulae were determined that enable to calculate eutectic and liquidus temperatures on the basis of chemical composition of the cast iron. The use of several formulae given in the literature for calculating the carbon equivalent of austenitic nickel cast irons was compared and evaluated. For utilization of determined results in practice a calculating programme has been compiled making possible to be used in operational practice. This programme is named Calculation of casting temperature of Ni-resist cast irons. After the entry of the melt chemical composition the programme calculates the all important parameters necessary to know and to be controlled for manufacture of high quality castings from austenitic nickel cast irons. Eutectic temperature, liquidus temperature and then based on it the tapping and casting temperatures are included among those parameters. Further on there are eutectic concentration of carbon, carbon equivalent, nickel equivalent, and a criterion evaluating a danger of chunky graphite formation.
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Properties of moulding mixtures of mixed bentonites after repeated use
Virgl, Vítězslav ; Neudert, Alois (referee) ; Kaňa, Václav (advisor)
High class mold is required for high quality castings. At present, the demands on molding materials are being extended by adding the strict requirement of environmentalists. A suitable variant that meets both demands are green sand molds. The goal of the thesis is to repeatedly cast experimental castings into molds made of 4 types of green sand mixtures. The technological properties of the molds will be compared, the degree of bentonite degradation will be assessed and the surface quality of castings will be assessed according to the amount of adherent molding mixture.
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History of ferrous alloy manufacture at Czech-Moravian Highlands
Kolníková, Eliška ; Kaňa, Václav (referee) ; Šenberger, Jaroslav (advisor)
This thesis deals with the history of steel production focused on the Czech-Moravian Highlands in the 14th – 19th century. The introduction provides a survey of chemical and physical reactions taking place in the steel production. The next chapter focuses on technology of production of raw iron and steel, there are also mentioned raw materials and equipment for their production. The last part deals with the various localities in the Czech-Moravian Highlands in the 14th - 19 century.
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