|
|
Influence of chemical composition of steel on structure and properties of stainless steels
Valenta, Pavel ; Čech, Jan (referee) ; Záděra, Antonín (advisor)
The thesis is focused on high-alloy austenitic and austenitic-ferritic (duplex) steel. The theoretical part includes research about high-alloy steels and basic introduction to this issue. In the practical part of the test there were casted refractory austenitic steel 30CH3N17G2L, duplex stainless steel 1.4462, low carbon steel and high carbon steel. On the castings of austenitic steel were made mechanical and technological tests. There were evaluated the effects of different casting temperature and casting wall thickness to the microstructures and macrostructures of steel, tensile strength and charpy impact tests. The technological tests compared technological properties of these steels.
|
|
|
Quality-evaluation tools for Al-alloy die-castings
Rozman, Jiří ; Vašíček, Richard (referee) ; Čech, Jaroslav (advisor)
The goal of this diploma thesis is to on a practical example, with use of the quality system, describe the current state of input casting inspection in Tribotec Ltd. and output casting inspection of casting suppliers in this company and to suggest a new way of output casting inspection on Tribotec Ltd. with higher quality of spoilage rate survey of supplying casting already at the input inspection stage.
|
|
|
Evaluation of porosity in Al-alloy die-castings
Havel, Jiří ; Nová, Iva (referee) ; Čech, Jaroslav (advisor)
The aim of this diploma thesis is to analyse the porosity of die - cast cast that were made of the alloy AISi9u3 in iron-foundry Skoda Car Mlada Boleslav. The analysis and the sample comparisons are based on my own measurements and are also connected with previous diploma thesis which deals with that issue and was drawn up at Technical University in Brno. All measurements were statistically tested.
|
|
|
Optimization of heavy steel castings manufacture
Procházka, Zdeněk ; Čech, Jan (referee) ; Šenberger, Jaroslav (advisor)
The Master’s thesis was conducted under the project FR-TI1/070 “Optimalization of heavy steel casting manufacture” in cooperation with ŽĎAS a. s. foundry. It evaluates rate of conchoidal fracture in samples extracted from experimental castings. The testing bar for the static tensile test were extracted from thermal axis of casting. The research part describes ways of deoxidating the liquid metal and usage of separate deoxidating chemical parts, followed by summary of research knowledge on conchoidal fractures. In the practical part, the process of sample evaluation is described. The conchoidal fracture, the surface of which was evaluated on the fracture surfaces, influences mechanical qualities of cast steel. Simultaneously, impacts of metallurgical factors on rate of conchoidal fracture were examined
|
|
|
Evaluation of porosity in Al-alloy die-castings
Straka, Jakub ; Nová, Iva (referee) ; Čech, Jaroslav (advisor)
The purpose of this diploma thesis is an evaluation of die-castings porosity, eventually the evaluation of seats with local squeeze in connection with their mechanical and structural properties. The swatches of alloy AISi9Cu3 were taken from the engine block made by Škoda Auto Company, Mladá Boleslav. To the evaluation and the comparison of the results there were used value of porosity with own measure and other student´s thesis of Brno University of technology. Sets of mechanical and structural properties were selected, evaluated and tested by statistical programs.
|
|
|
Using simulation to predict defects in and evaluate properties of die-cast Al-alloy castings
Morávková, Jitka ; Nová, Iva (referee) ; Čech, Jaroslav (advisor)
The purpose of this diploma thesis is comparing the quantity of porosity in die-cast aluminium casting with using simulation. The cast engine blocks were made by high pressure die-casting and a local squeeze casting (LSC) technology. There was also examined the relationship between porosity and mechanical properties of castings. There were evaluated and compared the results of my own measurements with data from previous students theses at the Faculty of Mechanical Engineering BUT. All data were tested by statistical tests. The comparison of simulation results and experimentally measured values was found a good programme-ability to simulate and estimate porosity.
|
|
|
Manufacture and defects of heavy castings
Vymazal, Aleš ; Čech, Jan (referee) ; Záděra, Antonín (advisor)
Objective of diploma thesis is to proceed analysis of actual technology in operational terms for concrete casting of bearing . Constructed by foundry of steel ŽĎAS a.s., Žďár nad Sázavou. After designing changes in technological process accomplish detail evaluation of mechanical properties and chemical homogenity of metal at selected parts of sample casting.
|
|
|
Evaluation of mechanical and structural properties of new block
Lefner, Jiří ; Nová, Iva (referee) ; Čech, Jaroslav (advisor)
The purpose of this dilploma thesis is to evaluate mechanical and structural properties of two types casts of Al-alloy (components of the engine block) which were made by different technologies. Die casting with local squeeze casting and without local squeeze casting. First of them is used in lot manufacture of the current engine block. The aim of the foundry is to change the technology and start to produce new block by the die casting without local squeeze casting. The samples were taken from the both parts (lower and upper part) of the current and the new engine block which are made in foundry of Skoda Auto a.c. in Mladá Boleslav. Sets of mechanical and structural properties were selected, evaluated and tested by statistical programs. It was used fifty casts of the engine blocks for the experiment.
|
|
|
Non-destructive testing of gear-wheels
Krejčí, Martin ; Juliš, Martin (referee) ; Čech, Jaroslav (advisor)
This diploma thesis resolves aplication of particular non-destructive testing methods while producing castings of steel wheels and quality control of this process. There are described fundamentals of flaw detection, determination of flaw-generation cause and suggestions for optimalization of casting process and increasing of its quality.
|
|
|
Using simulation to predict defects in and cast Al-alloy castings
Šolc, Petr ; Bařinová, Dagmar (referee) ; Čech, Jaroslav (advisor)
The aim of this work is comparing three casting process simulation programs for porosity and microstructure prediction capabilities for die-casting. After confronting these results with experimentally measured data taken from real castings it could be said that simulation is pretty accurate for DAS microstructure prediction and hot-spot areas. Amount of measured porosity could not be compared with predicted values because specimens were not taken from the exact hot-spot areas.
|
guest ::
