Prediction of volume fraction of primary austenite at solidification of lamellar graphite cast iron using thermal analyses

• Lamellar graphite cast iron was investigated with carbon equivalents varied between CE = 3.4 and 4.26, cast at various cooling rates between 0.195 and 3.5 °C s-1 covering the limits used for technical applications in the production of complex-shaped lamellar graphite cast iron. Registered cooling curves displaced in two positions in the casting were used to predict the solidification and microstructure formation mechanisms. The predicted volume fraction of primary austenite was compared with the fraction of primary austenite measured on colour micrographs with the help of image analyses. A good correlation has been obtained for medium and slow cooling conditions, while a less good correlation at fast cooling condition was attributed to the used protective environment to preserve thermocouples. The observed fraction and the predicted fraction of primary austenite were in good correlation and followed a consequent variation dependent on the carbon equivalent. Furthermore, the quality of the prediction was dependent on the used numerical algorithm involving cooling information from either one or two thermocouples.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Materialteknik -- Metallurgi och metalliska material (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Materials Engineering -- Metallurgy and Metallic Materials (hsv//eng)

Nyckelord

Coarsening

Lamellar graphite cast iron

Primary austenite

Thermal analyses

Algorithms

Austenite

Cooling

Forecasting

Graphite

Iron

Iron compounds

Phase diagrams

Solidification

Thermoanalysis

Thermocouples

Volume fraction

Carbon equivalent

Cooling conditions

Good correlations

Microstructure formation

Numerical algorithms

Technical applications

Cast iron

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