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Measurement of oxygen activity in ferro-alloys
Žák, Štěpán ; Čamek, Libor (referee) ; Záděra, Antonín (advisor)
The thesis deals with determination of the oxygen content in ferro-alloys with emphasis on direct oxygen activity measurement in the meltage. The practical part of the thesis contains statistical analysis of oxygen activity values measured in austenitic and duplex stainless steel meltages. The measurements were done in vacuum furnace before vacuuming and afterwards. Statistically significant dependency of oxygen activity on the temperature of meltage was discovered among the values measured after the vacuuming. Therefore, its value can be predicted based just on the temperature of the meltage. No statistically significant dependency was found among the values measured before vacuuming (except for the low Chromium austenitic stainless steel meltages). Hence, other factors need to be considered when predicting oxygen activity before vacuuming.
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Use of regenerated sand in molding mixtures
Henzlová, Michaela ; Žák, Štěpán (referee) ; Bořil, Petr (advisor)
The aim of the work is to verify the use of regenerated sand in molding mixtures within the school foundry at the Faculty of Mechanical Engineering of BUT in Brno. At the beginning of this thesis, a literature search is carried out on the given topic. As part of the experiment, suitable models and materials were first chosen for the production of samples. The models were molded with a molding mixture with new sand and a mixture with regenerated sand, some of them were also painted. After casting, the surface quality of individual samples was examined depending on the used molding mixture, material and coating. First, the surface was evaluated by a comparative method using standards, and then the tendency of the mixtures to bake was evaluated. At the end, all measurement results are compared.
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Measurement of oxygen activity in ferro-alloys
Žák, Štěpán ; Čamek, Libor (referee) ; Záděra, Antonín (advisor)
The thesis deals with determination of the oxygen content in ferro-alloys with emphasis on direct oxygen activity measurement in the meltage. The practical part of the thesis contains statistical analysis of oxygen activity values measured in austenitic and duplex stainless steel meltages. The measurements were done in vacuum furnace before vacuuming and afterwards. Statistically significant dependency of oxygen activity on the temperature of meltage was discovered among the values measured after the vacuuming. Therefore, its value can be predicted based just on the temperature of the meltage. No statistically significant dependency was found among the values measured before vacuuming (except for the low Chromium austenitic stainless steel meltages). Hence, other factors need to be considered when predicting oxygen activity before vacuuming.
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