|
|
Properties and micropurity of steels produced using vacuum metallurgy
Krontorád, Jakub ; Pernica, Vítězslav (referee) ; Záděra, Antonín (advisor)
This master thesis contains analysis of metallurgical quality of medium alloyed steel from the perspective of microcleanliness and content of dissolved gases. Apart from thorough research there are result of three melts from vacuum induction furnace (VCAP-Consarc), from which, conclusions are made. Each of the scrap material types (steel scrap, VD scrap and ESR scrap) had different metallurgical quality and initial microcleanliness, which influenced the final quality of the ingot. Lastly both degassing process and the thermodynamical probability of the reaction of silicon-oxide based sampling pipe with melt has been examined and calculated.
|
|
|
Design of a technology and checking the production of small steel ingots
Jakubčíková, Lucie ; Čamek, Libor (referee) ; Záděra, Antonín (advisor)
The thesis deals with the design of ingots from duplex (austenitic-ferritic) stainless steels in terms of minimal occurrence of axial porosity. The optimal shape and dimension of the ingot and the casting conditions are determined based on numerical simulations. The resulting internal quality of the realized ingot is evaluated. The presence of shrinkage porosity is determined by penetrant testing. The degree of chemical heterogeneity, the extent of macrosegregation, of selected elements in given ingot locations is measured by an optical emission spectrometer. Segregation values are compared with simulation results. The micro-purity of the ingot is assessed on the basis of metallographic samples.
|
|
|
Micropurity of steel manufactured in vacuum induction furnaces
Hořínek, Jakub ; Myška, Martin (referee) ; Záděra, Antonín (advisor)
During the production of steel, a certain proportion of non-metallic inclusions always arises, which significantly affects its final properties. The theoretical part of this thesis focuses on the effects of these impurities on the properties of steel and on ways to reduce their total content in steel. In the experimental part, the effect of vacuum melting, with casting in air, on the final micropurity of stainless steel was investigated. The results showed that the vacuum method was very effective as there was a significant reduction of the oxide inclusions content and oxygen content in the steel. Then, a part of the material from the first melting was remelted and the effect of repeated vacuum remelting of the material with casting in vacuum was investigated. The analysis showed a significant reduction in nitrogen content but the oxygen content remained almost the same.
|
|
|
Cleanliness of steels manufactured in vacuum induction furnaces
Pastyřík, Petr ; Záděra, Antonín (referee) ; Pernica, Vítězslav (advisor)
The topic of this thesis is the micropurity of steels manufactured in vacuum induction furnaces. The thesis describes 3 processes of steel melting using the same type of steel with different production parameters. Subsequently, samples were prepared and based on those samples the micropurities of the melting processes were evaluated. To obtain the results image analysis and electron microscope were used. Furthermore, elemental analyzer was used to measure the content of oxygen, nitrogen, sulphur and carbon. Afterwards, a discussion on micropurity and comparison of the melting processes is presented. In the conclusion section there are some possible suggestions concerning operation of the university foundry.
|
|
|
Cleanliness of steels manufactured in vacuum induction furnaces
Pastyřík, Petr ; Záděra, Antonín (referee) ; Pernica, Vítězslav (advisor)
The topic of this thesis is the micropurity of steels manufactured in vacuum induction furnaces. The thesis describes 3 processes of steel melting using the same type of steel with different production parameters. Subsequently, samples were prepared and based on those samples the micropurities of the melting processes were evaluated. To obtain the results image analysis and electron microscope were used. Furthermore, elemental analyzer was used to measure the content of oxygen, nitrogen, sulphur and carbon. Afterwards, a discussion on micropurity and comparison of the melting processes is presented. In the conclusion section there are some possible suggestions concerning operation of the university foundry.
|
|
|
Micropurity of steel manufactured in vacuum induction furnaces
Hořínek, Jakub ; Myška, Martin (referee) ; Záděra, Antonín (advisor)
During the production of steel, a certain proportion of non-metallic inclusions always arises, which significantly affects its final properties. The theoretical part of this thesis focuses on the effects of these impurities on the properties of steel and on ways to reduce their total content in steel. In the experimental part, the effect of vacuum melting, with casting in air, on the final micropurity of stainless steel was investigated. The results showed that the vacuum method was very effective as there was a significant reduction of the oxide inclusions content and oxygen content in the steel. Then, a part of the material from the first melting was remelted and the effect of repeated vacuum remelting of the material with casting in vacuum was investigated. The analysis showed a significant reduction in nitrogen content but the oxygen content remained almost the same.
|
|
|
Design of a technology and checking the production of small steel ingots
Jakubčíková, Lucie ; Čamek, Libor (referee) ; Záděra, Antonín (advisor)
The thesis deals with the design of ingots from duplex (austenitic-ferritic) stainless steels in terms of minimal occurrence of axial porosity. The optimal shape and dimension of the ingot and the casting conditions are determined based on numerical simulations. The resulting internal quality of the realized ingot is evaluated. The presence of shrinkage porosity is determined by penetrant testing. The degree of chemical heterogeneity, the extent of macrosegregation, of selected elements in given ingot locations is measured by an optical emission spectrometer. Segregation values are compared with simulation results. The micro-purity of the ingot is assessed on the basis of metallographic samples.
|
guest ::
