Andrzej Gazda

Thermophysical properties of CuNiMoMn Austempered Ductile Iron


The aim of the study was to determine the thermophysical characteristics of CuNiMoMn austempered ductile iron (ADI) obtained as a result of standard, one-step heat treatment performed at various temperatures.
Temperature-dependent physical properties of structurally differentiated CuNiMoMn ADI were measured using thermal analysis techniques. Coefficient of thermal expansion, specific heat capacity, density, thermal diffusivity and thermal conductivity can be utilized in designing technological applications, developing databases and computer modeling of austempering heat treatment of ductile cast iron.
Austempering heat treatment causes a significant decrease in thermal diffusivity of ADI as compared to the initial as-cast ductile iron, in the temperature range of stability of ausferritic structure. It was found that as the temperature of isothermal transformation increases, the thermal diffusivity and thermal conductivity decreases despite an increase in the amount of carbon-enriched austenite. This can be explained by the predominant influence of fine acicular ferritic structure on the properties of heat transport in the ADI under study.

Keywords: ADI, ausferrite, thermal analysis, thermophysical properties, thermal conductivity,
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