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Coating properties of cutting tools carbide
Doležalová, Petra ; Bumbálek, Bohumil (referee) ; Osička, Karel (advisor)
Diploma thesis is divided into two parts. The first part is focused on theoretical description of coating methods, on currently used coatings, their properties and it is also focused on description of methods, which are used for analyzing each property. The second part focuses on testing of coatings and analyzing of the values obtained from experiments. The aim of this thesis is then to compare the properties of the tested coatings.
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Optimization of Manufacturing and Assembling Technology of the Valve Bolt
Hrouzková, Andrea ; Zapletal, Josef (referee) ; Doležal, Pavel (advisor)
The thesis aimed to study the impact of manufacturing and assembly technology, the valve bolt fitted to diesel high pressure pump CP3 in the Bosch, which has been found to leak. As experimental material was chosen heat treated bolts M16x1,5 made of material 12 050th. Groups of samples were produced in two ranges hardness. Experimental determination of the optimum range of hardness was assessed on the basis of the results of the process of the screw and set the value of plastic deformation of the sealing surfaces of the parts. Experimental section also deals with the analysis of bearing surfaces on the pump and the components, after the screw process. To some extent, is observed as surface treatment
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The study of the spot size influence on the depth of hardening of the material 42CrMo4 during laser hardening
Kříž, Daniel ; Daněk, Ladislav (referee) ; Mrňa, Libor (advisor)
This master thesis is focused on surface hardening by using disk laser. Ten samples made of 42CrMo4 steel were hardened at varying speeds of quenching and diameter of the laser beam. The theoretical part initially describes the types of lasers. Further it describes methods of surface hardness processing such as kinds of hardening and chemical-thermal treatment, followed by description of the used material. Images of macrostructure, microstructure and compared values of hardness of single samples are evaluated in the experimental part. The thesis subsequently contains a technical-economic evaluation. Appropriate parameters for surface laser hardening are evaluated in the conclusion.
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Heat treatment of iron alloys with carbon
Kubíček, Antonín ; Štěpánek, Roman (referee) ; Čupera, Jan (advisor)
This thesis deals with the processes of heat treatment, their impacts on microstructure of iron alloys with carbon and their influence on hardness of these alloys. In the research part of this thesis are discussed the alloys, which are found within the Fe-Fe3C metastable system, principles and technologies of heat treatment processing with focus on the annealing, methods of microstructure examination and hardness measurement. In the experimental part is documented and evaluated the influence of various types of annealing on hypoeutectoid and hypereutectoid steels and the influence of graphitization on the hypoeutectic cast iron. The evaluation involves comparison of microstructures obtained by light and scanning electron microscopy and comparing the hardness in the green state and after annealing.
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Use of laser scanning head for surface hardening
Jedličková, Veronika ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
The diploma thesis addressed the issue of laser surface hardening using dynamic oscillation of the laser beam. The theoretical part presents the hardening technology and suitable using of laser equipments. The fiber laser YLS 2000 was used in the experiment and the hardened material was steel 12 050, which is suitable for laser hardening. The influence of two selected parameters of the scan head on the resulting structure and hardness of hardening layers was examined. Based on the results, the choice of optimal parameters for identical conditions with the experiment was recommended.
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The Influence of Heat Treatment on the Structure and Mechanical Properties of Tool Steels
Tobolík, Stanislav ; Němec, Karel (referee) ; Molliková, Eva (advisor)
This bachelor thesis deals with the properties of tool steels after heat treatment. The theoretical part describes the properties of iron and its alloys with carbon, and an overview of the use of steel. It is also discussed in detail the heat treatment of tool steels and manufacturing process analysis and metallographic sample. In the last part of the bachelor thesis there are described the mechanical testing of metals. In the practical part it is tested structure and mechanical properties of the selected tool steels for two types of heat treatment and the results are compared with the requirements imposed on it.
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Effect of modification of HVOF sprayed alloy NiCrBSi by electron beam on its structure
Pongrácz, Jakub ; Havlík, Petr (referee) ; Foret, Rudolf (advisor)
This thesis deals with surface re-melting by electron beam of thermal sprayed material NiCrBSi by method HVOF. The microstructure, chemical and phase composition, hardness and abrasive wear resistance were evaluated in depending on the electron beam parameters and modes of the electron beam 6-poinst and line. Observed microstructure was better after both methods of re-melting. The splats were not observed, coating porosity decreased and structure was more homogenous. Structure and phase analysis was acquired by light microscopy, scanning electron microscopy, energy dispersive spectroscopy and x-ray diffraction. A small change in hardness between modes of re-melting was observed, but measured hardness was higher than in sample without re-melting. Similar results were observed for abrasion resistance.
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The influence of alloying elements n the hardenability of carburization steels
Komoráš, Miroslav ; Helán, Jiří (referee) ; Jan, Vít (advisor)
This bachelor thesis is dealing with material analysis of cams used in radial hydraulic motors. The goal of this bachelor thesis is to identify root causes for not proper quenching of some parts made of material 34Cr4 by using microstructure analysis and hardness measurement. Theoretical part of thesis looks into influence of alloying particles on quenchability of carburizing steels, methods of heat treatment and carburizing. Experimental part follows up microstructure analysis and case depth hardness of analysed samples.
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Weldability of steels for steam turbine parts
Jech, David ; Hutařová, Simona (referee) ; Juliš, Martin (advisor)
The aim of contemporary standard welding technologies is to create compact welds with high value of solidity and toughness in laboratorial and operational conditions. This welding technology is asserted in new creep - resisting steels on basis of steel CrMoV and CrMoNiV, which have high value of solidity and creep - resistance. The thesis deals with problems connected with the weldability of steels for steam turbine rotors and it´s aim is to interpret the structural and mechanical features of the weld joint for material combinations under consideration. For the assessment of weld joint features has been used measuring of micro hardness and hardness according to Vickers, microstructure was observed by methods of light microscopy.
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