  The known data on the heat capacity of magnetite (Fe3O4), hematite (Fe2O3)
and iron (Fe) at different temperatures are approximated by formulas containing
phase transition temperatures as varying parameters. This allows to take into
account the effect of phase transition shifts, for example, due to impurities,
lattice defects, grain sizes or high cooling rates. For this purpose, the
entire target temperature range from 0 C to 1300 C is divided by phase
transition temperatures into separate intervals. The conjugation of the
approximating functions between the intervals at the magnetic transition point
is performed without a gap, and at the point of polymorphic transformation
(alpha Fe - gamma Fe) with a finite gap of heat capacity values. For wustite
Fe1-xO which does not experience phase transformations, the temperature
dependence of the heat capacity is approximated by a single smooth function. In
combination with previously obtained formulas for the density of iron oxides
and iron the proposed approximations allow us to estimate the specific mass
heat capacity of oxide scale depending of its structural composition and
temperature. By model calculations it is shown that at temperatures of 200 C
and 900 C specific mass heat capacity of oxide scale practically does not
depend on the percentage of its individual components and is approximately 750
and 850 J/(kg K) respectively. At a temperature of about 575 C, on contrary,
actually possible variations in the composition of oxide scale can lead to a
change in its specific heat capacity from 850 to 1150 J/(kg K). The obtained
dependencies are recommended for use in mathematical modeling of production and
processing of steel products in the presence of oxide scale on their surface
