The possibility of controlling the solidification and cooling time of
castings creates prospects of improving their structure and by the same
their properties. Thermal properties of the mould constitute therefore
an important factor which is necessary to consider while seeking for the
mentioned improvement. The presented work illustrates the method of
determining some basic thermal coefficients of moulding material, i.e.
the coefficient of temperature equalisation a2, known also as the
temperature diffusivity, and the heat accumulation coefficient b2, which
characterises the ability of moulding material to draw away the heat
from a casting. The method consists in experimental determining the
temperature field within the mould during the processes of pouring,
solidification and cooling of the casting. The performed measurements
allow for convenient and exact calculations of the sought-after
coefficients. Examinations were performed for the oil bonded moulding
sand of trade name OBB SAND ‘E’. The experiment showed that the obtained
value of b2 coefficient differs from the value calculated on the basis
of theoretical considerations available in publications. Therefore it
can be stated that theoretical calculations of the heat accumulation
coefficient are thus far not sufficient and not quite reliable, so that
these calculations should be verified experimentally.

IS - No 2
KW - Theoretical basis of casting processes
KW - Moulding materials
KW - Oil binder
KW - Heat accumulation coefficient for moulding sands
KW - Temperature equalization coefficient
T1 - Determination of Heat Accumulation Coefficient for Oil Bonded Moulding Sands