STUDY ON INGOT MAKING PRACTICE (II)

The authors have studied on the characteristics and differences of acid and basic open-hearth furnace steels in origination of sand cracks during the ingot makimg process. (cf Rep. 1, Tetsu-to-Hagane, 38, 1952, No. 5.) The subjects of study were as follows:(1) Deoxidizing products during the ingot making process.(2) Corrosion of various refractories by molten steel.(3) Oxidation of molten steel by atmosphere during the ingot making process.The results obtained were as follows:(1) It was evident from the analytical results of non-metallic inclusion (sand) in steel in furnace before tapping, in the ladle and in the runner, or from analysis of scum in the mould, that basic molten steel produced much more deoxidizing products than acid molten steel in the ingot making process.(2) According to observation of the runner surface on which the molten steel bad passed through, its analytical results, relation between[Mn] and[Si] contents in these molten steel before tapping and in the ladle and those oxidizing products, it was found that corrosion of various refractories by basic molten steel was more ε ctive than acid molten steel.(3) From the changes of[C], [Si], [Mn], [Al], [Cr], [FeO], etc., in these molten steels before tapping and after the finish of casting, it was inferred that oxidation of basic molten steel by atmosphere during the ingot making process was heavier than the acid.