Effect of graphite morphology on tensile properties of flake graphite castiron

The mechanical properties of flake graphite cast iron were studied using no rmal cast and unidirectionally solidified (UDS) test pieces. Their chemical composition was eutectic, namely CE = 4.3%, differing only in sulfur conte nt. To eliminate the influence of the discontinuity of graphite at the eute ctic cell boundary we used UDS samples. Fully annealed tensile test pieces were used to exclude the influence of the matrix. The experimental results are as follows: The tensile strength and elongation of normal and unidirect ionally solidified cast iron are increased by the sulfur addition as the gr aphite morphology is modified. The tensile strength is improved by UDS. One of the reasons must be based on the continuity of the matrix. Nevertheless , the tensile strength of the UDS samples is not as strong as that of spher oidal graphite cast iron because the fracture occurs at the graphite-termin ated area in the aligned graphite samples.