| The effects of silicon and cooling velocity on the matrix structure of spheroidal graphite cast iron have been studied. In the preparation of spheroidal graphite cast iron, Fe-Si-Mg and Fe-Si alloys were used as additive and inoculant respectively. The important results obtained in this study are as follows. (1) As the silicon content is increased by 0.1% in samples with diameter of 10, 20 and 30mm, the amount of pearlite decreases by 4% in hypo-eutectic region but by 1.8% in hyper-eutectic region. (2) However, the amount of ferrite is increased by 4.3% in hypo-eutectic but 1.6% in hyper-eutectic region per 0.1%Si addition in the same samples having various diameters such as 10, 20 and 30mm. (3) The effects of silicion content are larger than those of cooling velocity on the matrix structure. |
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