PURPOSE: To easily remove a sintered slag layer to be formed on the head of a steel ingot by spraying a mixture composed of ≥2 kinds of compds. of alkaline (earth) metals having low m.p. on the surface of a molten steel in the stage of ingot making thereby coating the surface of the molten steel.
CONSTITUTION: A surface coating material is added to the surface of the molten steel to prevent the oxidation thereof in the initial period of pouring of the molten steel or during the pouring. The mixture composed of ≥2 kinds of the alkali metal compds. or alkaline earth metal compds. having 800W1,400°C m.p. is used as the surface coating material and is sprayed onto the surface of the molten steel. BaCl2, NaCl, BaCO3, Na2CO3, CaSi, etc. are selected as the above-mentioned compd. The sintered slag layer in the head part of the unidirectionally solidified steel ingot made by the above-mentioned manner has the weak adhesive power to the steel ingot and can be thoroughly removed by shot blasting and slight scarfing. The yield of the steel ingot body is thus improved.
NAKANISHI KYOJI
KINOSHITA KATSUO
YAMAZAKI HISAO
