| Abstract |
| In this study, the 121 samples from buried DCIPs were collected, and the levels and interrelationships of spherical graphite morphology, chemical composition, and tensile strength were analyzed. The results are as follows. First, the graphite structure of DCIP samples contained some spherical graphite structure, spherical graphite structure included some flake graphite structure or flake graphite structure without spherical graphite. In addition, it seems to be the more flake graphite structure, the more the tensile strength tended to decrease. Second, the content variation of the chemical composition of the DCIP was very large. Magnesium (Mg) content, which directly affects spheroidal graphite structure, was mostly lower than the recommended standard (> 0.03%). Therefore, there could be various other causes,the normal spheroidal graphite structure was 66.1% due to lack of magnesium content at 121 DCIP samples. Third, the tensile strength of 121 DCIP samples ranged from 1,333 to 5,177 kgf/cm2 (mean 3,783 kgf / cm2), with very large deviations. The variation in tensile strength seems to be due to chemical composition, spheroidal graphite structure, and various environmental factors during the manufacturing process. |
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| Key Words |
| Chemical composition, Ductile cast iron pipe, Physical property, Spheroidal graphite |
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