| Summary: | 碩士 === 國立臺北科技大學 === 材料科學與工程研究所 === 97 === The main propose of this thesis is to investigate the influence of metallographic on cast iron which have trace element. It could offer producer a feasible way and recognize the trace element to use it. The variable in the experiment include trace element type, quantity, reaction time and spheroidizing methods. And quantity of inoculation, size of inoculation and inoculate methods. In the experiment to make Nodular Cast Iron is use rare earth element (Ce) which pure rate above 99% to be nodularizer add into molten iron (FCD-450). Then inoculate with FeSi. Experiment temperature are within 1400 to 1500℃ in every furnace lot, and test pour out at different time. We use sand box to be cast mold which thin wall type in every factory, in order to know Thin Wall Nodular Cast Iron spheroidizing rate influence by nodularizer decay.
We know produce procedure of Nodular Cast Iron, melting → spheroidizing → inoculation → casting → sampling. Spheroidizing and inoculation reaction are perform in ladel. Due to this experiment principal issue is nodularizer decay time in molten iron, molten iron pour out at different time, so we need to adjust procedure to match experiment demand.
Experiment result shows that use cerium 3% to replace magnesium to be nodularizer, and add inoculate FeSi 1.5%. When spheroidizing 15~20 min., we can obtain Thin Casting Nodular Cast Iron nodularity 90%. when spheroidizing at a long time later, nodularity below 50%, to replace vermicular and flat piece graphite.
In addition, this article is directed to manufacturing process about use cerium to replace magnesium to manufacture Thin Casting Nodular Cast Iron.
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