The paper proposes a methodology useful in verification of results of dilatometric tests aimed at determination of temperatures defining
the start and the end of eutectoid transformation in the course of ductile cast iron cooling, based on quenching techniques and
metallographic examination. For an industrial melt of ductile cast iron, the effect of the rate of cooling after austenitization at temperature
900°C carried out for 30 minutes on temperatures TAr1
start and TAr1
end was determined. The heating rates applied in the study were the
same as the cooling rates and equaled 30, 60, 90, 150, and 300°C/h. It has been found that with increasing cooling rate, values of
temperatures TAr1
start and TAr1
end decrease by several dozen degrees.