Numerical model of heterogeneity of the ductile cast-iron

• Autorzy: Stransky K. , Kavicka F. , Dobrovska J. , Stetina J. , Sekanina B.
• Języki publikacji: EN

Abstrakty

EN

An original three-dimensional (3D) model of solidification is used to describe the process of solidification and cooling of massive 500×1000×500 mm cast-iron castings. The castings are cast in sand moulds. The calculated mode of the kinetics of the temperature field of the casting is verified during casting with temperature measurements in selected points. The sizes and positions (xi, yi, zi, where i = 1,2,3 is the number of samples taken) of the experimental samples are exactly defined and corresponding with the decreasing rate of solidification. The experimental samples – 15 mm in diameter and 12 mm high – are metallographically analysed and also in terms of heterogeneity of the chemical composition. The coordinates xi, yi, zi characterise approximately – within an accuracy of +/- 5 mm – the centres of the samples. Successively, the local solidification time (i.e. the time the specified position of the casting, defined by the coordinates xi, yi, zi, remains within the temperature range between the liquidus and solidus) is also calculated using the 3D model. The following dependences are later determined according to the experimental and calculated data: the average size of the graphite spheroids rg, graphite cells Rb and the average distances among the particles of graphite Lg – always as a function of the local solidification time [xi, yi, zi]. Furthermore, it has been found out that the given basic characteristics of the structure of the cast iron rg, Rb and Lg are directly proportional to the logarithm of the local solidification time. The original spatial model of solidification can therefore be used in its first approximation for the assessment of the pouring structure of massive cast-iron castings.

Słowa kluczowe

EN

ductile cast iron; solidification time; segregation; structural characteristic; modelling

PL

odlew; krzepnięcie; modelowanie; charakterystyka strukturalna

• Wydawca: Instytut Metalurgii Żelaza im. Stanisława Staszica
• Czasopismo: Prace Instytutu Metalurgii Żelaza
• Rocznik: 2009
• Tom: T. 61, nr 5
• Strony: 137--141
• Opis fizyczny: Bibliogr. 8 poz.

Twórcy

autor

Stransky K.

autor

Kavicka F.

autor

Dobrovska J.

autor

Stetina J.

autor

Sekanina B.

• Brno University of Technology

Bibliografia

• 1. Kavicka F. and others: Optimisation of the properties and the technology of the production of massive cast-iron castings. Final Research Report for the GAČR Project No. 106/01/1164. VUT, FSI, Institute of Power Engineering, Brno 2003, 68 pages.
• 2. Stetina J., Ramik P., Heger J., Dobrovska J., Sekanina B.: The Numerical and Experimental Investigation of a Concasting Process, The Book of Abstracts of the ASME/JSME Thermal Engineering Joint Conference, Kohala Coast, Hawaii USA, March 2003, p. 103.
• 3. Chvorinov N.: Crystallisation and heterogeneity of Steels. NČSAV, Prague 1954, 381 pages.
• 4. Smrha L.: Solidifi cation and Crystallisation of Steel Ingots. SNTL, Prague 1983, 305 pages.
• 5. Kavicka F., Sekanina B., Stetina J., Stransky K., Gontarev V. and Dobrovska J.: Numerical optimization of the method of cooling of a massive casting of ductile cast-iron. Materials and technology 43 )2009) 2, 73-78.
• 6. Belko J., Stransky K.: Analysing Graphite in Cast-iron. Research Report (611-57, 811-28) VTUO Brno, Brno, November 2002.
• 7. Winkler Z., Stransky K.: Heterogeneiy of the Compositions of Elements in Ductile Cast-iron Castings. Research Report (811-11-02) VTÚO Brno, Brno, December 2002.
• 8. Murdoch J., Barnes J.A.: Statistical Tables for Science, Engineering, Management and Business Studies. Macmillan, Cranfield 1970, 40 pages.