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Influence of chemical composition, casting temperature and the used deoxidation on technological properties of austenitic chrome-nickel steels
Myška, Martin ; Dulava, Martin (referee) ; Záděra, Antonín (advisor)
The thesis deals with austenitic stainless steel ČSN 42 2930, ASTM A351 CF8 and evaluates its mechanical and technological properties. The first part of this work is focused on properties of austenitic steels, it describes the process of melting and casting of steel on the basis of the realized experiments. It also deals with the mechanical properties of the used steel. The second section of the thesis is dedicated to the historical development of the maximum fluidity tests and main factors affecting the maximum fluidity of alloys. Maximum fluidity values have been processed on the basis of different casting temperatures of the maximum fluidity tests of the used steel. The third part of the work examines the effect of the casting temperature on the feeding distance of the used steel as well as the influence on its shrinkage rate.
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Precipitation of Intermetallic Phases in Austenitic-Ferritic Duplex Steels
Myška, Martin ; Foret, Rudolf (referee) ; Čech, Jan (referee) ; Záděra, Antonín (advisor)
This PhD thesis addresses the issue of precipitation of intermetallic phases in cast duplex stainless steel according to the ASTM A890 Gr4A standard. The aim of the thesis was to determine the amount of precipitated intermetallic phases depending on the temperature and holding time during isothermal annealing and under anisothermal conditions during cooling of the material in the temperature range from 1000 to 600 °C. The partial aim of the work was to determine the relationship between the amount of precipitated intermetallic phases and the mechanical properties of cast steel ASTM A890 Gr4A. As part of the work, the description and prediction of the kinetics of precipitation of intermetallic phases using the Johnson-Mehl-Avrami equation were verified. The relationship between the amount of precipitated intermetallic phases and the failure character of the material was determined by fractographic evaluation. The critical cooling rate of the casting was determined to ensure the minimum toughness of the steel that is desirable to reduce the risk of cracking during cooling of duplex stainless steel castings.
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Design and manufacture of Mjölnir hammer by casting
Bubník, Šimon ; Bořil, Petr (referee) ; Myška, Martin (advisor)
The aim of this bachelor's thesis was to design suitable technologies for the production of Thor's hammer casting within the BUT school foundries. The work contains a theoretical part, which summarizes the casting technology itself, focusing on the production of non-permanent molds, cores and molding compounds. Furthermore, the work contains a practical part, which describes the process of casting production from the creation of the model and its printing, the subsequent production of the mold to the finishing of the casting.
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Production of castings using Rapid prototyping
Baránek, Martin ; Myška, Martin (referee) ; Bořil, Petr (advisor)
The work is focused on the production of a decorated stand casting using rapid prototyping and reverse engineering methods. The thesis first performs a literature search dealing with selected additive technologies usable for the production of foundry patterns or molds. Subsequently, the work describes the basics of 3D scanning technology. The experimental part of the thesis describes the production process of castings. The original was first digitized using a hand-held scanner, the obtained data were modified as needed and served as an input for 3D printing of permanent foundry patterns. Their production took place on a FDM 3D printer PRUSA MK3S and they were made of PLA material. The models were then formed into sand molds. The resulting castings were made of grey cast iron.
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Insulating materials in foundry technology
Slowiaczek, Kamil ; Krutiš, Vladimír (referee) ; Myška, Martin (advisor)
The thesis deals with materials that ensure the insulation of foundry furnaces and ladles. The first part discusses the properties that most affect the insulation capacity. The second chapter focuses on the overview and characteristics of refractory materials. In the next part of the thesis, the most used insulation materials are named and approached. Finally, the thesis deals with the composition of the lining of the electric arc furnace, ladles and the rammed lining of the induction crucible furnace.
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Micropurity of steel manufactured in vacuum induction furnaces
Hořínek, Jakub ; Myška, Martin (referee) ; Záděra, Antonín (advisor)
During the production of steel, a certain proportion of non-metallic inclusions always arises, which significantly affects its final properties. The theoretical part of this thesis focuses on the effects of these impurities on the properties of steel and on ways to reduce their total content in steel. In the experimental part, the effect of vacuum melting, with casting in air, on the final micropurity of stainless steel was investigated. The results showed that the vacuum method was very effective as there was a significant reduction of the oxide inclusions content and oxygen content in the steel. Then, a part of the material from the first melting was remelted and the effect of repeated vacuum remelting of the material with casting in vacuum was investigated. The analysis showed a significant reduction in nitrogen content but the oxygen content remained almost the same.
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Production of lever fuse casting for hose coupling
Tvrdoň, Tomáš ; Myška, Martin (referee) ; Pernica, Vítězslav (advisor)
The first part of this bachelor’s thesis is just a theory and it is focused on producing castings with method of impermanent moulds. You can find here basic classification of moulds and afterwards sand moulds and ceramic moulds are described. The second part is practical and it is focused on a production of lever fuse which defends disconnection of the fire hose when it is under the pressure of water. Lost wax casting was chosen for the production. In this part is described full process from pattern making, gluing to wax tree, covering to metal casting. The whole practical part is accompanied by authentic pictures which were made during the process.
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Lining of the induction furnaces
Kopečný, Vendelín ; Pernica, Vítězslav (referee) ; Myška, Martin (advisor)
This work deals with lining of electric induction furnaces. The first part describes the preparation of lining, its function during the running of furnace and also its tearing down at the end of work process. In the thesis is also discussed the use of rammed crucibles. The materials used for lining and rammed crucibles are described also in the sense of their chemical properties in connection with the possibilities of their use under different conditions. The practical part of the thesis describes the process of lining the electric induction furnace, which was realized by the author under the supervision of the supervisor.
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Manufacture of cylinder head casting for engine renovation Jawa 50
Pastyřík, Petr ; Myška, Martin (referee) ; Bořil, Petr (advisor)
This project elaborats the manufacture of a cylinder head casting for an engine renovation of Jawa 50. Based on the literary pursuit of suitable foundry technologies and using 3D printing in foundry a casting production technology was designed and the cylinder head was made. The part was designed in the CAD software and then printed on a 3D printer. The printed model was formed in ceramic shell form, then melted and the form was annealed. After that the cast was casted. The last operations were fettling and finishing machining.
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