National Repository of Grey Literature 32 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Shrinkage prediction of graphitic cast iron
Blažek, Petr ; Kaňa, Václav (referee) ; Krutiš, Vladimír (advisor)
The thesis deals with the shrinakage prediction of graphitic cast iron. In the theoretical part, volume changes and influences on graphene expansion are described in detail. Furthermore, pouring methods and simulation parameters related to schrinkage and pouring are broken down in the work. In the practical part, thermophysical data and metallurgical quality of the metal are optimized in the simulation. For the specified casting, the risers were designed according to theoretical methods and the simulation optimization module. Using optimized risers, it was possible to save the volume of metal per raw casting by about 25 %. For castings from the soft bentonite mold and from the mold from the GEOPOL® (a self hardening mixture), the volume was measured using a 3D scan. When they were compared, an uneven increase in the volume of the bentonite mould casting was 1.2 %. The increase was due to the strain of the mold in the graphite expansion.
Influence of the metallurgical quality of the aluminum alloy melt on the properties of investment castings
Urban, Antonín ; Krutiš, Vladimír (referee) ; Kaňa, Václav (advisor)
The thesis focuses on the influence of shell temperature, wall thickness, and metallurgical treatment of the melt on the mechanical properties and structure of the AlSi10Mg aluminum alloy processed using the investment casting technique. The experimental part was conducted in the school foundry. Prior to the experiment, a series of simulations were performed to verify the feasibility of the experiment. The thesis describes the experimental design and conditions under which the experiment was conducted. Furthermore, it presents the evaluation of mechanical properties based on wall thickness, shell temperature, and modification. In the conclusion of the thesis, the effect of strontium modification is assessed with respect to wall thickness and shell temperature during casting, using micrographs from metallographic samples.
Improving the internal quality of aluminum alloy castings by the optimization of foundry technology
Mátl, Vojtěch ; Krutiš, Vladimír (referee) ; Kaňa, Václav (advisor)
This master’s thesis deals with the topic of improving the internal quality of aluminium alloy castings using foundry technology optimization. Theoretical part of this thesis consists of five chapters. These chapters deal with topics of internal defects in castings, solidification of aluminium alloys, numerical simulations in foundry, feeding and use of chills. The second part of this thesis is experimental. It focuses on defect analysis of investigated castings, casting technology simulation and suggestions for its improvement, with consideration for liquid metal utilization.
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.
Introduction of special die lubricant - micro spraying into the conditions of high pressure die foundry
Šromota, Michal ; Roučka, Jaromír (referee) ; Krutiš, Vladimír (advisor)
The master thesis, consisting of a theoretical and practical part, focuses on the issue of high pressure die casting, specifically the treatment of the die using micro spray technology. The goal of the thesis was to map the processes that need to be changed in the high pressure die casting foundry in order to successfully implement the use of micro-spraying. The practical part describes the introduction of micro spray technology in the foundry KOVOLIT Modřice a.s. In this case a transition from the conventional spraying method to the micro-spraying is made. After testing, both stable production and the expected savings associated with the operation of micro-spraying were achieved on the selected casting, and therefore it was decided to convert the production of the selected casting to this technology.
Optimization of simulation parameters in the process of spraying a metal die
Vlček, Ondřej ; Šotka, Pavel (referee) ; Krutiš, Vladimír (advisor)
This thesis, prepared for Škoda Auto, deals with the optimization of die casting simulation parameters in software ProCast. The aim was to develop and validate a methodology for inputting die spray parameters. The optimization itself was performed on a high pressure die casting simulation for an engine block casting. The temperature field was taken from the real die using a thermographic camera and then compared with the simulation. The parameters of the simulation were adjusted according to the experimentally obtained data and literature, and the course of optimization required changing not only the parameters related to the external treatment, but also the material models, or changing the heat transfer coefficient between the die and the casting. By the procedure, the temperature field of the original simulation, which differed from reality by more than 100 °C, was optimised so that the results at the measured locations did not reach a difference of more than ± 20 °C. Therefore, the procedure used can be applied as the required methodology for optimising further simulations.
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.
Optimization of properties of 3D printed patterns for the technology of casting into ceramic shells
Štěpán, Radim ; Horáček, Milan (referee) ; Krutiš, Vladimír (advisor)
This thesis is focused on optimizing the 3D printed patterns used for investment casting into ceramic shells technology. The technology of hybrid investment casting and complete process of ceramic shells manufacturing is described in this thesis. During the burnout of the 3D printed pattern a problem with shell cracking arises. This problem was solved by optimizing the 3D printed pattern – the amount of pattern infill and venting the pattern cavity. The optimizations were successfully verified on the sword guard pattern.
Production of aluminum castings using metal inserts in the technology of casting into ceramic shells
Straka, Pavel ; Zemčík, Ladislav (referee) ; Krutiš, Vladimír (advisor)
The thesis is focused on manufacturing of aluminium castings with inserts by the hybrid investment casting technology. Three measures were proposed to avoid shell cracking caused by thermal expansion of insert. It seems that the covering of insert with a wax is the most efective solution, becasue after dewaxing a gap is formed, which allows insert to dilate. The other solution was based on change of molochite sand to quartz, which has a higher thermal expansion. The last mean to prevent the shell from cracking was adjustment of dewaxing cycle from shock to gradual. Ceramic shell was heated from room temperature to 650 °C. This solution did not avoid shell cracking. Then the simulation of shell heating, pouring of metal and the solidification was made. The information obtained by the manufacturing of experimental casting was used to prototype casting of impeller.
Modification of ceramic shells to increase its break up after casting process
Škriečková, Natália ; Horáček, Milan (referee) ; Krutiš, Vladimír (advisor)
This master´s thesis deals with the problem of the disintegration of shell moulds after casting. Too high residual strength increases the cost of operations associated with the final cleaning of castings. The aim was to analyze the current state of the art and to optimize the production of moulds in MoraviaTech a.s. so that the removal of the ceramic shell after casting is easier. In the first part, a literature analysis of the influences that could have a positive effect on the speed of shell removal is made. In the practical part, experiments are conducted comparing the amount of shell removed as a function of time between modified ceramic shells and shells produced by the company. In the last part, the results of the individual measurements are evaluated and conclusions and recommendations for MoraviaTech a.s. are drawn from them.

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