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High-temperature embrittlement of 14%Cr ODS ferritic steel in liquid lead environment
Dohnalová, Eva ; Čelko, Ladislav (referee) ; Hadraba, Hynek (advisor)
The thesis deals with the high-temperature embrittlement of 14%Cr ODS ferritic steel in liquid lead environment. The 14%Cr ferritic ODS steel ODM401 manufactured by powder metallurgy technology was used as an experimental material. The effect of the long-term annealing, surface corrosion attack in the melt Pb and Pb-Bi on the microstructure and mechanical properties was described. The subsequent microstructural changes were evaluated by means of scanning electron microscopy and transmission electron microscopy The mechanical behaviour of the experimental material was proven by means of microhardness test, impact test and static tensile test. The fractographical evaluation of fracture surfaces were performed on all samples. The surface attack and outstanding microstructural ganges were found after the long-time exposition of the steel in Pb/Pb-Bi melts at temperature 550°C/1000h and 500°C/1000h respectively. The embrittlement of the steel after exposition in Pb/Pb-Bi melts was comparable to the embrittlement after high-temperature annealing of the steel at temperature 650°C/1000h.
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Analysis of Iron-Phosphorus Reaction Products Formation During Heat Treatment Processes
Skoumalová, Zuzana ; Jan, Vít (referee) ; Doležal, Pavel (advisor)
During high pressure pulsation tests repeated cracks of CP3. housings occur. High pressure pump CP3 is part of injection system Common Rail. Cracks can be caused by segregation of phosphorous from a washing medium on grain boundaries during subsequent heat treatment process. The present master´s thesis focuses on analysis of phosphorous compounds on specimen surface made from steel 20MnCr5, which were soaked in solutions with different concentration of phosphorous. Master’s thesis is also focused on potencial influence of phosphorous on structure and properties of this material. The first part of the thesis provides a summary of current knowledge in the studied field, experimental results can be found in the second part. The surface analysis XPS, the light microscopy, the scanning electron microscopy equipped by energy dispersive chemical analysis, the glow discharge optical emission spectroscopy, the methods of the phase analysis by means of the X-ray diffraction and impact test were used.
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High temperature service embrittlement of EUROFER´97 steel
Stratil, Luděk ; Jan, Vít (referee) ; Hadraba, Hynek (advisor)
The thesis describes effect of long-time ageing on the microstructure and properties of the Eurofer´97 steel. The ferritic-martensitic reduced activation steel Eurofer´97 is candidate structural material for in-core components of proposed fusion reactors. Thesis is focused on examination and description of brittle-fracture behaviour of the steel. Properties of the steel were investigated in as-received state and state after long-time ageing. Detailed microstructure studies were carried out by means of optical and electron microscopy and also by means of quantitative electron microscopy. Mechanical properties were evaluated also in both states by means of hardness tetsing, tensile testing and Charpy impact testing. Fractography analysis of fracture surfaces was carried out on samples after Charpy impact testing.
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High-temperature embrittlement of 14%Cr ODS ferritic steel in liquid lead environment
Dohnalová, Eva ; Čelko, Ladislav (referee) ; Hadraba, Hynek (advisor)
The thesis deals with the high-temperature embrittlement of 14%Cr ODS ferritic steel in liquid lead environment. The 14%Cr ferritic ODS steel ODM401 manufactured by powder metallurgy technology was used as an experimental material. The effect of the long-term annealing, surface corrosion attack in the melt Pb and Pb-Bi on the microstructure and mechanical properties was described. The subsequent microstructural changes were evaluated by means of scanning electron microscopy and transmission electron microscopy The mechanical behaviour of the experimental material was proven by means of microhardness test, impact test and static tensile test. The fractographical evaluation of fracture surfaces were performed on all samples. The surface attack and outstanding microstructural ganges were found after the long-time exposition of the steel in Pb/Pb-Bi melts at temperature 550°C/1000h and 500°C/1000h respectively. The embrittlement of the steel after exposition in Pb/Pb-Bi melts was comparable to the embrittlement after high-temperature annealing of the steel at temperature 650°C/1000h.
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Analysis of Iron-Phosphorus Reaction Products Formation During Heat Treatment Processes
Skoumalová, Zuzana ; Jan, Vít (referee) ; Doležal, Pavel (advisor)
During high pressure pulsation tests repeated cracks of CP3. housings occur. High pressure pump CP3 is part of injection system Common Rail. Cracks can be caused by segregation of phosphorous from a washing medium on grain boundaries during subsequent heat treatment process. The present master´s thesis focuses on analysis of phosphorous compounds on specimen surface made from steel 20MnCr5, which were soaked in solutions with different concentration of phosphorous. Master’s thesis is also focused on potencial influence of phosphorous on structure and properties of this material. The first part of the thesis provides a summary of current knowledge in the studied field, experimental results can be found in the second part. The surface analysis XPS, the light microscopy, the scanning electron microscopy equipped by energy dispersive chemical analysis, the glow discharge optical emission spectroscopy, the methods of the phase analysis by means of the X-ray diffraction and impact test were used.
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High temperature service embrittlement of EUROFER´97 steel
Stratil, Luděk ; Jan, Vít (referee) ; Hadraba, Hynek (advisor)
The thesis describes effect of long-time ageing on the microstructure and properties of the Eurofer´97 steel. The ferritic-martensitic reduced activation steel Eurofer´97 is candidate structural material for in-core components of proposed fusion reactors. Thesis is focused on examination and description of brittle-fracture behaviour of the steel. Properties of the steel were investigated in as-received state and state after long-time ageing. Detailed microstructure studies were carried out by means of optical and electron microscopy and also by means of quantitative electron microscopy. Mechanical properties were evaluated also in both states by means of hardness tetsing, tensile testing and Charpy impact testing. Fractography analysis of fracture surfaces was carried out on samples after Charpy impact testing.
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