| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 101 === Ductile iron, with superior mechanical properties, has been applied in various industrial fields; high silicon ductile iron has a good resistance to high temperature oxidation, but with the adding of molybdenum elements will result in the increasing of high temperature strength.
In this paper, using a water-cooled copper mold to achieve unidirectional solidification of high silicon molybdenum ductile iron castings, quality of spheroidal graphite and microstructure of eutectic carbides are presented. Thermal analysis of the casting by using Differential Scanning Calorimetry (DSC) analysis was conducted to calculate value of latent heat of this grade of ductile iron. Electrolytic deep etching technique was used to study the stereo structure of fish-bone M6C structure in the eutectic carbide.
The Results shows regardless of the cooling rate is high or low, fish bone-like eutectic carbides appears between grain boundaries, at that vicinity which precipitates with tiny granular carbide; several stereo morphologies of this eutectic carbides were studied and based on that a growth model is proposed in this thesis; DSC analysis of high silicon molybdenum ductile iron in the heating and cooling process latent heat average value with the literature is equivalent.
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