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Segregation during solidification in austenitic-ferritic stainless steels
Kejha, Richard ; Čech, Jan (referee) ; Pernica, Vítězslav (advisor)
The master thesis deals with processes of segregation in austenitic-ferritic stainless steels. The introductory part consists of characteristics features of austenitic-ferritic steels and theoretical analysis of segregation processes. The second part shows practical measurements of segregation in experimental casting. Macrosegregation was measured on a spectrometric analyzer and simultaneously solved in the simulation program MAGMA. The aim of this thesis is to verify the effect of solidification time and dwell time between liquidus and solidus temperature on the chemical heterogeneity of duplex stainless steel casting of about 500 [mm]. Chemical heterogeneity was solved for selected alloying and accompanying elements such as C, Mo, Ni, Mn, Cr. The microsegregation was not addressed. Comparison of the mechanical properties of cast and heat treated duplex steel was done by tensile testing of samples cut from the center of the casting.
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Manufacturing, use and properties of nickel alloys
Kejha, Richard ; Blažík, Petr (referee) ; Záděra, Antonín (advisor)
This thesis presents a literary recherche of matters concerning on industrial use of nickel aluminates, especially on refractory and incandescent alloys. In this dissertation are witten basic market brands of constructional, refractory and incandescent alloys, and then their selected representatives. There are listed the basic properties of given materials and their approximate comparison. The basic constructional materials are monel alloys based on Ni-Cu, which achieves very good mechanicl properties and excellent corrosion resistence. Refractory and incandescent materials are mostly based on Ni-Cr or Ni-Cr-Fe. Their mechanical features are very different in normal conditions and even in high operating temperatures because there are used different kinds of addition elements and their concentration. These alloys are usually additioned by elements like W, Cu, V, Al, Nb, Ti, Ta, Mo, Co, Zr, B.
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Segregation during solidification in austenitic-ferritic stainless steels
Kejha, Richard ; Čech, Jan (referee) ; Pernica, Vítězslav (advisor)
The master thesis deals with processes of segregation in austenitic-ferritic stainless steels. The introductory part consists of characteristics features of austenitic-ferritic steels and theoretical analysis of segregation processes. The second part shows practical measurements of segregation in experimental casting. Macrosegregation was measured on a spectrometric analyzer and simultaneously solved in the simulation program MAGMA. The aim of this thesis is to verify the effect of solidification time and dwell time between liquidus and solidus temperature on the chemical heterogeneity of duplex stainless steel casting of about 500 [mm]. Chemical heterogeneity was solved for selected alloying and accompanying elements such as C, Mo, Ni, Mn, Cr. The microsegregation was not addressed. Comparison of the mechanical properties of cast and heat treated duplex steel was done by tensile testing of samples cut from the center of the casting.
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Manufacturing, use and properties of nickel alloys
Kejha, Richard ; Blažík, Petr (referee) ; Záděra, Antonín (advisor)
This thesis presents a literary recherche of matters concerning on industrial use of nickel aluminates, especially on refractory and incandescent alloys. In this dissertation are witten basic market brands of constructional, refractory and incandescent alloys, and then their selected representatives. There are listed the basic properties of given materials and their approximate comparison. The basic constructional materials are monel alloys based on Ni-Cu, which achieves very good mechanicl properties and excellent corrosion resistence. Refractory and incandescent materials are mostly based on Ni-Cr or Ni-Cr-Fe. Their mechanical features are very different in normal conditions and even in high operating temperatures because there are used different kinds of addition elements and their concentration. These alloys are usually additioned by elements like W, Cu, V, Al, Nb, Ti, Ta, Mo, Co, Zr, B.
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