| 1. |
- Diószegi, Attila, 1962-, et al.
(författare)
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Modelling and simulation of heat conduction in 1-D polar spherical coordinates using control volume-based finite difference method
- 2016
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Ingår i: International journal of numerical methods for heat & fluid flow. - 0961-5539 .- 1758-6585. ; 26:1, s. 2-17
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Tidskriftsartikel (refereegranskat)abstract
- Purpose - The purpose of this paper is to obtain a finite difference method (FDM) solution using control volume for heat transport by conduction and the heat absorption by the enthalpy model in the sand mixture used in casting manufacturing processes. A mixture of sand and different chemicals (binders) is used as moulding materials in the casting processes. The presence of various compounds in the system improve the complexity of the heat transport due to the heat absorption as the binders are decomposing and transformed into gaseous products due to significant heat shock. Design/methodology/approach - The geometrical domain were defined in a 1D polar coordinate system and adapted for numerical simulation according to the control volume-based FDM. The simulation results were validated by comparison to the temperature measurements under laboratory conditions as the sand mould mixture was heated by interacting with a liquid alloy. Findings - Results of validation and simulation methods were about high correspondence, the numerical method presented in this paper is accurate and has significant potential in the simulation of casting processes. Originality/value - Both numerical solution (definition of geometrical domain in 1D polar coordinate system) and verification method presented in this paper are state-of-the-art in their kinds and present high scientific value especially regarding to the topic of numerical modelling of heat flow and foundry technology.
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| 2. |
- Diószegi, Attila, 1962-, et al.
(författare)
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Shrinkage porosity formation in cast iron components
- 2018
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Ingår i: 73rd World Foundry Congress "Creative Foundry", WFC 2018 - Proceedings. - : Stowarzyszenie Techniczne Odlewnikow Polskich/Polish Foundrymen's Association. - 9788390430638 ; , s. 207-208
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Konferensbidrag (refereegranskat)abstract
- Shrinkage porosity formation mechanisms at production of cast iron components is particularly complex and became more and more difficult to understand since the shape casting complexity have been increased more and more in advanced component applications. The present work intends to summarize the state of the art in understanding the shrinkage porosity formation mechanism of cast iron based on a series of key publications, MSc and PhD theses performed in collaboration between cast iron component users, producers and researchers.
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| 3. |
- Diószegi, Attila, et al.
(författare)
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Solubility of Hydrogen and Nitrogen in liquid cast iron during melting and mold filling
- 2016
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Ingår i: 72nd World Foundry Congress, WFC 2016. - : The World Foundry Organization (WFO). - 9781510833128 ; , s. 52-53
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Konferensbidrag (refereegranskat)abstract
- Defect formation like gas- and shrinkage porosity at cast iron component production is related to the content of gaseous elements in the liquid metal. The present work investigate the solubility of hydrogen and nitrogen in liquid iron aimed for production of lamellar and compacted graphite cast iron. The used methods and instruments are a combination of commercial measuring devices and novel experimental assemblies for measuring solubility of hydrogen and nitrogen during melting and mold filling of a complex shaped cast component. The obtained results reveal the role of the charge material and the mold filling on the solubility of the investigated elements.
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| 4. |
- Diószegi, Attila, et al.
(författare)
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Surface Turbulence at Flow of Gray Cast Iron
- 2011
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Ingår i: Key Engineering Materials. - Switzerland : Trans Tech Publications. - 1013-9826 .- 1662-9795. ; 457, s. 422-427
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Tidskriftsartikel (refereegranskat)abstract
- Gray cast iron has been investigated with respect to surface turbulence during mould filling. Different levels of flow velocities have been provoked in a vertically parted sand mould. The thermal resistant transparent front side of the mould permitted the observation of the flow pattern due to high speed camera registration. The registered frames including the liquid surface were investigated using image analyses. The results show good correlation between the average flow velocity and the liquid iron surface extension. Consequently it has been demonstrated that an increased absorption of hydrogen and nitrogen during mould filling is dependent on the level of liquid surface turbulence.
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| 10. |
- Belov, Ilja, et al.
(författare)
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A thermal conductivity model for grey iron
- 2024
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Ingår i: International Journal of metalcasting. - : Springer. - 1939-5981 .- 2163-3193. ; 18:3, s. 2107-2117
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Tidskriftsartikel (refereegranskat)abstract
- Thermal conductivity is an important property for many iron cast components, and the lack of widely accepted thermal conductivity model for cast iron, especially grey cast iron, motivates the efforts in this research area. The present study contributes to understanding the effects alloy microstructure has on thermal conductivity. A thermal conductivity model for a pearlitic cast iron has been proposed, based on the as-cast alloy composition and microstructural parameters obtained at different solidification rates. According to the model, available parallel heat transfer paths formed by connected graphite flakes across eutectic cells are determined by the space between dendrite arms. The uncertainties both for model inputs and for validation measurements have been estimated. Sensitivity analysis has been conducted to result in better understanding of the model behaviour. The agreement between modelled and measured thermal conductivities has been achieved within 5% on the average for the investigated samples.
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