The purpose of this diploma paper is the nodule count of cast iron by means of two different methods: sandwich method and cored wire method. Besides using both methods, a comparison was made between the sandwich methods done in Ivančna Gorica and Črnomelj respectively. The cored wire method was only used in Črnomelj as it is not being used in Ivančna Gorica. Test castings were analyzed and then analyses were compared visually, with thermal analysis, chemical analysis, and metallographic analysis. The experimental part was done in the foundry of Livar company.
Generally speaking, the process of nodule count done on both locations and with both methods is satisfactory, which can be confirmed by the proof that samples were not visibly porous. Differences and imperfections were detected in small panels with rollers. The best example of nodule count was made with the cored wire method in Črnomelj. The study showed that the graphite size was the largest in the case of nodule count done with the sandwich method in Črnomelj, and the smallest in the case of nodule count done with the sandwich method in Ivančna Gorica, meaning that the nodule count done with the sandwich method in Ivančna Gorica was done better than the nodule count with the sandwich method in Črnomelj. The study revealed that the percentage of perlite in all cases differs somewhat, which is the result of perlite-forming elements. All cases revealed an imperfection, namely that graphite is not evenly distributed across the entire matrix. There are places where graphite cannot be spotted at all, which is the result of poor melt grafting. Besides a non-homogenous distribution of graphite, I also found that in microstructure there appeared graphite size grades 6, 7 and 8. In the microstructure of the nodule count done with the cored wire method in Črnomelj, I detected degenerated graphite.
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