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Machining of hardened parts
Havlík, Daniel ; Osička, Karel (referee) ; Polzer, Aleš (advisor)
This bachelor thesis is focused on the machining of hardened parts. The beginning of the work is devoted to the analysis of specific materials, 42CrMo4, 42CrMoS4 and 50CrMo4. Next described thing is heat treatment. The main part of this work consists of theoretical analysis turning of hardened parts and theoretical analysis of the thread whirling of ball screw, where the principle of ball screws is also described.
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Influence of Homogenizing on Mechanical Properties of AZ91 Alloy
Provazníková, Andrea ; Liškutín, Petr (referee) ; Věchet, Stanislav (advisor)
This bachelor thesis includes photos and graphic representations of the influence of heat treatment on the mechanical properties of magnesium alloy AZ91. The structures of the alloy are recorded on the light microscopy pictures as well as photographs taken using a scanning microscope of fracture areas in the material. Results of a Tensile Test determining the strength and plastic properties and measuring of hardness and microhardness of the material are also included.
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Evaluation of upsetting test
Vávra, Roman ; Císařová, Michaela (referee) ; Řiháček, Jan (advisor)
This work is focused on theoretical and practical processing upsetting test. There is an explanation of their significance in engineering. Also, there are described various kinds of tests and their evaluation. Furthermore, the work deals with the experiment for a specified material MS 68. This material was compacted using two test machines equipped with measuring software. First machine is a hydraulic press CZR 600 with software DEWESoft and the second is a universal testing machine ZD 40 using software M-Test. An evaluation based on the collected data is included in the form of deformation resistance curves of tested material.
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Analysis of Circular Bars Shearing Process
Dohnalová, Eva ; Hůlka, Jiří (referee) ; Foret, Rudolf (advisor)
In these days customers require a high quality as well as precision of products together with a cost that is as low possible. The cost of products can be reduced in a way of batch production. Implementation of the batch production requires a detailed plan of a technological process to avoid making depreciated products or series of products. A software package can be used to simulate the technological process of shearing to avoid difficulties of particular technological process. This bachelor paper contains analysis of technological process of shearing of circular section rods. The results of the analysis are going to be included in FEM simulations. The effect of the technological process of shearing on material was determined by optical and scanning electron microscopy method. The microhardness measurement was used to analyse the deformation hardening of the examinated material.
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Tube Flaring Technology under Dynamic Conditions
Macháček, David ; Forejt, Milan (referee) ; Peterková, Eva (advisor)
This master thesis is divided into three main parts. In first part is more closely described the method of tube flaring. Tube flaring was chosen for analysis of biaxial stress, in this thesis particularly in the presence of high strain rate. In the second part is more closely described influence of high strain rate on the forming process. There is described influence of high strain rate on behavior of the material, hardening, change of quasi-static yield strength to the dynamic yield strength, influence of high strain rate on the microstructure and more. During the description of these processes there is effort to describe the cause of these changes as well. For this task was used domestic and foreign literature, as well as peer review papers whose authors study intensively this problematic. Besides all of the above there is also derived the velocity of elastic and plastic wave. In the end is evaluated experiment, in which was done tube flaring, which is part of this master thesis. Results from the 3D optical system ARAMIS are interpreted with the help of Microsoft Excel, where the chosen results were used as the input to the equations modified for the dynamic loading.
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Analysis of cracking of aluminium profiles during bending process
Kalivoda, Ondřej ; Šebek, František (referee) ; Vosynek, Petr (advisor)
The presented thesis was created in cooperation with Siemens, s.r.o. and deals with the analysis of the bending of aluminium sheets. These products are used as conductors of electrical energy. The problem happened when the bending angle was 90 ° when there was a violation outside of the bend. The aim of the thesis is to verify whether the bend is correctly designed using analytical and empirical relations and the finite element method. Because of the requirement for running numerical simulation on one of the freely available software the Salome Meca program environment was used. The results of numerical simulation did not confirm that the violation should occur. In deeper analysis appeared doubts whether it is possible to correctly evaluated result only by data from tensile test. In the final part, there are recommended some experiments which would be necessary for the correct calibration of the ductil fracture criteria.
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Methods of secondary influencing steel and steel ingot structures
Šprta, Pavel ; Pernica, Vítězslav (referee) ; Blažík, Petr (advisor)
This bachelor’s thesis deals with heat treatment of steels. Iron-carbon diagram and basics of heat treatment are described in the beginning of the literature search. Further the thesis focuses on austenitization and changes during decomposition of austenite. Introduction to transformation diagrams and their use is also included in this thesis. At the end the thesis focuses on description of individual heat treating methods. The experimental section contains metallographic analysis of 4 samples made of low carbon steel.
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Heat treatment of aluminum castings
Mátl, Vojtěch ; Pernica, Vítězslav (referee) ; Kaňa, Václav (advisor)
This bachelor thesis deals with the topic of heat treatment of aluminium castings. The first part of this thesis comprises of casting alloys and casting technology summary, followed by description of aluminium heat treatment. The second part descibes an experimet, that examins the effect of conditions during aging upon final aluminium alloy properties.
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Low Temperature and Cryogenic Treatment of Casehardened Parts
Bílková, Lenka ; Juliš, Martin (referee) ; Kouřil, Miloslav (advisor)
This work deals with the assessment of the influence of low-temperature treatment on the structure and properties of casehardened surface layer of parts. The objective was to assess whether low-temperature treatment is sufficient, insufficient, or unnecessary for the given purpose. Gears which form a part of Zetor tractors gear boxes were used as samples. Thirteen pairs of frozen and non-frozen samples were used; they were taken from production batches throughout 2007, their hardness was assessed and furthermore, the experiment itself, freezing casehardened and hardened samples to different temperatures reaching as low as -196°C, was carried out. A moderate increase in hardness was registered with the majority of the frozen samples, which proved the effectiveness of the low-temperature treatment.
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