In the present paper the influence of different microstructure parameters o
n the tensile strength of gray iron is shown. It can be concluded that the
volume fraction of primary solidified phase and the specific phase interfac
e of free graphite have a considerable influence on the tensile strength. H
owever, it is difficult to get a unique relationship between the microstruc
ture and mechanical properties under different chemical compositions, nucle
ation and cooling conditions.
A mathematical model is presented for the simulation of cooling and solidif
ication of gray iron. This includes the heat conduction from the solidifyin
g alloy into the mould and the solidification process. Here, the fraction o
f primary dendrites is calculated by the Scheil-Equation. During the eutect
ic crystallization, nucleation and grain growth processes are considered, T
he development of graphite lamellae morphology inside eutectic grains has b
een included into the model. Microstructure parameters, which have been cal
culated for different chemical compositions, nucleation and cooling conditi
ons, are related to corresponding experimentally determined tensile strengt
hs.