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Deformation of tool steels after quenching in vacuum furnaces
Abu Khait, Yosef ; Němec, Karel (referee) ; Pacal, Bohumil (advisor)
In this thesis, the deformation stages, which take place in tool steels after quenching in vacuum furnaces, were studied. This study was focused on the heating and cooling conditions during this type of quenching. In the experimental part, the deformation changes in particular samples made of tool steel after vacuum quenching were analyzed. Minor changes in the volume of samples at higher quenching temperatures compared to lower temperatures were observed.
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The Influence of Structure and Heat Treatment on Properties of Steels for Bearings
Pytlíčková, Kateřina ; Dočkal, Ing, Michael (referee) ; Věchet, Stanislav (advisor)
Heat treatment influences structure and characteristics of treatmented material. Good heat treatment of steels for bearings ensures hardness of matrix 60 - 65 HRC, whereas structure has be formed by tempered fine needle-shaped martensite with definite part of residual austenite. Carbides should be evenly dispersed, they mustn´t create carbide network and carbide lines. Quality of steels for bearings is also influenced by volume and morphology of inclusions in the matrix. In this diploma thesis various conditions of heat treatment were to be set up with the aim of choose the optimal ones. These ensures perfect martensite transformation and full hardening of all component. Quenching from 760 °C – 770 °C was quite unsatisfactory. At this temperature resulting structure was ferritic-perlitic, because martensite transformation did not pass. Too long hold on hardening temperature also had unfavourable influence on resulting structure and characteristics. In this case, structure was created by very coarse needle-shaped martensite. Coarsening of martensite needle locally exceeded maximum allowed level. In the structure there was also possible to watch partly soluted globular carbides. Optimal heat treatment is quenching from 850 °C – 870 °C followed by tempering at 220 °C. Resulting structure quite agree with above-mentioned needs. This heat treatment can be recommended for technical practise.
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Heat processing principle of operation thermal resistance annealing.
Špičková, Petra ; Humár, Anton (referee) ; Kalivoda, Milan (advisor)
The project assigned for the bachelors study program B 2307 analyses the theory of heat processing in general and furthermore resistance annealing with the focus on the technology developed by the company Heatmasters. Examples of processing methods used at other technology providers are presented, inclu-ding documentation and datasheets. Resistance annealing is based on the heat transfer from a resistive wire, which heats up by electrical current. The thermal energy is then transferred to the target material through heat radiation or con-ductance. The resistance heat processing is used both for welding and for an-nealing. Nowadays is the documentation and recording of the heat processing of significant importance. Possibilities exist that allow recording of temperature during the entire cycle of the heat processing and subsequently providing the result evidence in a form of a certificate.
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Design of material for drawing tools
Petrecký, Adam ; Juliš, Martin (referee) ; Klakurková, Lenka (advisor)
Bachelor thesis deals with optimalization of material choice and its heat treatment for cold work forming tools. The thesis deals with specific failure of seizure during the cold forming of high strenght steel for automotive. First part deals with theory of cold forming and tool steels made for this purpose. The main goal of the thesis was to discover cause of the failure and deduce solution as choice of alternative material with its proper heat treatment and surface coating. Solution has to show higher lifespan and also has to deliver economical benefit.
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Vliv uhlíku na tepelné zpracování ocelových součástí
Šťastný, Vojtěch
Bachelor´s thesis deals with problematic of heat treatment and influence of carbon on properties of iron alloys. The beginning of the work describes the production process, input materials and equipment for the production of pig iron, cast iron and steel. There are also described elements influencing properties of steels, definition and distribution of cast iron and steel. The thesis deals with heat treatment and its types. In the thesis thereis also described diagram iron-iron carbide (Fe-Fe3C) and its individual structural phases. The next part of the thesis deals with problematic of transformaci on diagrams. The last part of the thesis deals with the transformations of cooled austenit and its individual species.
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Performace rychlosti martenzitické transformace při snímání silových akustických pulsů
Mazal, Aleš
Thesis topic: Performance speeds martensitic transformation when shooting power acoustic pulses deals with the thermal processing of steel when recording acoustic emission. The theoretical part deals with the hot gas transition, martensitic transformation, refining steel, and basic information about the acoustic emission. The practical part consisted of sensing acoustic emission during hardening steels in water and in oil, followed by detecting the hardness in different locations of the sample. Evaluation was carried out using a hardness test, metallographic images and records acoustic emission obtained during hardening.
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Deformation of tool steels after quenching in vacuum furnaces
Abu Khait, Yosef ; Němec, Karel (referee) ; Pacal, Bohumil (advisor)
In this thesis, the deformation stages, which take place in tool steels after quenching in vacuum furnaces, were studied. This study was focused on the heating and cooling conditions during this type of quenching. In the experimental part, the deformation changes in particular samples made of tool steel after vacuum quenching were analyzed. Minor changes in the volume of samples at higher quenching temperatures compared to lower temperatures were observed.
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Vliv tepelného zpracování na mechanické vlastnosti oceli
Čupa, Jan
Bachelor thesis deals with the heat treatment of steel and its influence on the mechanical properties of steel. In the introduction is the procedure to production of raw iron and steel. Thesis shows the distribution of steel, depending on their chemical composition, method of production and labeling according to Czech National Standards. Thesis also describes structural phases and some transformations of iron alloys. The next chapter provides an overview of the heat treatment methods and part of the description of each species is usually their influence on the properties of steel. The final part of thesis deals with the lattice defects, that may arise during the process.
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