Abstract
We investigated the Mg treated nodular cast iron (D. C. I.) by the reducing refining in the acid or basic electric arc furnace. The results obtained can be summarized as follows:
1) By the reducing refining, it is able to get a strong desulphurizing and deoxidizing action for molten iron. Necessary Mg amount for D. C. I. in cupola is about 0.4%, but in this case Mg amount is reduced, for example Mg amount in the case of basic furnace is 0.11 to 0.17%, and it is 0.18 to 0.23% in the case of acid furnace. By the reducing refining in electric furnace, the drosses get into casting and depth of skrinkage hole are reduced.
2) The test piece is made by JIS No. 4 type in a green sand mould and annealed to ferrite matrix. The results are as follows:
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3) By the reducing refining, it can get an excellent desulphurizing action for molten iron. The sulphur content of raw material is the range between 0.024 to 0.031%, but in the basic furnace smelting desulphurizing action is 65 to 96%, the range of sulphur content is between 0.001 to 0.010%, while in acid furnace desulpharizing action is 63 to 89%, the range of sulphur content is 0.003 to 0.011%.
