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- Dugic, Izudin, 1962-
(författare)
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Metal Expansion Penetration on Concave Casting Surfaces of Cylinder Heads Cast in Grey Cast Iron
- 2009
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Konferensbidrag (refereegranskat)abstract
- Cylinder heads have an extremely complex shape with large areas of concave casting surfaces. The concave casting surfaces are often associated with metal expansion penetration problems or other surface defects, e. g. surface shrinkage. The defects cause high production costs due to component rejection and increased fettling time. This report presents an investigation of the microstructure in grey cast iron close to the sand-metal interface affected by metal penetration in a complex shaped casting. The dominant penetration defect observed in the cylinder heads was expansion penetration. Even pre-solidification penetration and sand crack defects were observed. The microstructure found in the non penetrated areas is typical for solidification of grey iron cast in sand moulds.
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- Dugic, Izudin, 1962-, et al.
(författare)
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Metal Expansion Penetration on Concave Casting Surfaces of Grey Cast Iron Cylinder Heads
- 2006
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Cylinder heads have an extremely complex shape with large areas of concave casting surfaces. The concave casting surfaces are often associated with metal expansion penetration problems or other surface defects, e. g. surface shrinkage. The defects cause high production costs due to component rejection and increased fettling time. This report presents an investigation of the microstructure in grey cast iron close to the sand-metal interface affected by metal penetration in a complex shaped casting. The dominant penetration defect observed in the cylinder heads was expansion penetration. Even pre-solidification penetration and sand crack defects were observed. The microstructure found in the non penetrated areas is typical for solidification of grey iron cast in sand moulds.
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- Dugic, Izudin, 1962-, et al.
(författare)
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The Influence of Inoculation on the Metal Expansion Penetration With Respect to the Primary and Eutectic Solidification
- 2005
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The mechanism of metal expansion penetration of grey cast iron components is dependent on both solidification anomalies at the metal – mould interface and the inclination of the sand mould to permit the metal liquid to penetrate between the sand grains. The present work utilizes the latest development of primary austenite inoculation in combination with classic eutectic inoculation to limit the metallurgical contribution to metal expansion penetration. A solid shell containing the primary austenite dendrite network constitutes the barrier between the liquid metal and mould interface. Inoculants of both the primaryand eutectic phase control the permeability of the dendrite network.
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- Dugic, Izudin, 1962-
(författare)
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The mechanisms of metal expansion penetration during solidification of grey cast iron
- 2006
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The production of high quality castings requires the casting surface to be clean and free from defects. One type of defect often found is caused by metal penetration into the sand mould. Metal penetration is a casting surface condition resulting from either physical, mechanical and/or thermochemical reactions or a combination of these at the mould–metal interface. The metal penetrates into the voids between the sand grains to various depths without displacing the grains, thus yielding a phase of sand grains surrounded by metal and frequently by mould-metal reaction products. The present work is devoted to investigating the mechanisms of metal expansion penetration during solidification of grey cast iron.The phenomenon of metal expansion penetration has been examined experimentally. A series of test castings were produced at two foundries, to study the influence of chemical composition, the casting temperature and the addition of inoculants with respect to both primary and eutectic phases.The experiments show that the type and amount of inoculant, the casting temperature and the chemical composition influence the metal expansion penetration.Two major types of metal expansion penetration mechanisms are suggested with respect to the nucleation and growth of the primary and eutectic phases. The expansion penetration mechanisms found in the experimental work were also identified on complex shaped industrial castings such as clutch components and cylinder heads.The entire casting process was simulated using commercial software, and in which nucleation and growth of all relevant phases was considered in order to investigate the solidification characteristics and porosity formation in the casting. A good correlation between the simulation and experiments on real castings was found.Density and volume change in grey cast iron seem to play a decisive roll in the occurrence of metal expansion penetration. Laboratory measurements of density variations are difficult. A novel method of modeling the density variation in cast iron has been introduced.
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