Dergiler / Metalurji / 1997 / Cilt: 21 - Sayı: 111-özel sayı
Dökme demir işparçalarının bilgisayar benzetimi yardımıyla tasarımlarının ve işlem koşullarının optimizasyonu
- Dergi
- Metalurji
- Sayfa
- 5–17
- DOI
- —
Özet
During recent years the application of computer simulation tools has become widely accepted within the foundry industry. The application of casting simulation has been most beneficial for avoiding shrinkage scrap, improving cast metal yield of steel castings, and in tooling design for permanent mould applications. Due to the unique metallurgical and solidification phenomenon which occur in cast and ductile irons, the use of simulation tools has been up to now restricted. A new development, which became available two years ago, has solved this problem by the use of micro modelling. The micro modelling tool is based on a kinetic model and microstructural consideration of the melt inoculation, phase formation, and solidification characteristics and therefore accurately predicts the graphite expansion and porosity formation. This allows the quantitative prediction of microstructures, shrinkage, and porosity formation as a function of the nominal composition, casting conditions, and the metallurgical treatment of the melt. Based on this information the solid, state phase transformations can also be predicted, which results in the final room temperature microstructure and the resulting mechanical properties. This information provides an ideai interface between the casting designer and foundry engineers to optimise both, the casting design and the methoding of a component at the earliest stage in development. This paper introduces the concept of micromodelling of cast and ductile irons and explains current capabilities and future developments. Several case studies demonstrate the benefit of using these tools under industrial conditions.
Abstract
During recent years the application of computer simulation tools has become widely accepted within the foundry industry. The application of casting simulation has been most beneficial for avoiding shrinkage scrap, improving cast metal yield of steel castings, and in tooling design for permanent mould applications. Due to the unique metallurgical and solidification phenomenon which occur in cast and ductile irons, the use of simulation tools has been up to now restricted. A new development, which became available two years ago, has solved this problem by the use of micro modelling. The micro modelling tool is based on a kinetic model and microstructural consideration of the melt inoculation, phase formation, and solidification characteristics and therefore accurately predicts the graphite expansion and porosity formation. This allows the quantitative prediction of microstructures, shrinkage, and porosity formation as a function of the nominal composition, casting conditions, and the metallurgical treatment of the melt. Based on this information the solid, state phase transformations can also be predicted, which results in the final room temperature microstructure and the resulting mechanical properties. This information provides an ideai interface between the casting designer and foundry engineers to optimise both, the casting design and the methoding of a component at the earliest stage in development. This paper introduces the concept of micromodelling of cast and ductile irons and explains current capabilities and future developments. Several case studies demonstrate the benefit of using these tools under industrial conditions.