| In the spheroidal graphite cast iron, the effects of graphite size were studied on the mechanical properties such as tensile strength, yield strength, elongation, reduction of area and hardness. The important results obtained are as follows. 1. As the graphite size increased, the tensile strength decreased lineally little by little in case of less than 3.0% of Si and varied little in case of 3.0% and 3.3% of Si. For example, with 0.1㎜ increase of the graphite size in case of 1.8% of Si, the tensile strength decreased as much as 0.4 kg/㎟. 2. The elongation incresed in proportion the increase of graphite size. For example, with 0.1㎜ increase of the graphite size, the elongation increased as much as 0.5% in case of 1.8% of Si. 3. The graphite size did not influence the hardness of the spheroidal graphite cast iron which had the same matrix structure and composition and the Brinell hardness was about 148 in case of 1.8% of Si. |
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