PURPOSE: To prevent the generation of material defects, cracks, etc. and to reduce the cost of production by adding a flux which does not contain B or B compd. to a cast steel contg. C at a specific value or below during or right after pouring of said steel.
CONSTITUTION: A molten steel 5 contg. ≤1.4% C is poured through a pouring pipe 7 into a casting mold 1. The flux which does not contain B or compd. is added to the molten steel during or right after pouring. The material defects and cracks do not arise even if the flux contg. B or B compd. is used in the case of ≥1.4% C. For example, a flux contg. SiO2+Na2CO3 as an essential component is used as the flux which does not contain B or B compd. The intrusion of B into the cast steel and the generation of the material defects, cracks, etc. are prevented by the above-mentioned method, by which the cost of production is reduced.
KOGA AKIO
KAWAI TETSUAKI
YASUDA KAZUMI
HAYASHIDA MICHIYA
