熔解雰囲気のことなる白銑の黒鉛化

抄録

The principal emphasis in this research has been placed on determining what the effects of the melting-furnace atmospheres on graphitization are. Two kinds of white iron were employed as raw material for melting. One was commercial white iron, the other was synthetic white iron made from electrolytic iron, electrode graphite and metallic silicon. The melt of white iron was held at 1320∼1330°C for 30 min in vacuum or an atmosphere of gas such as argon, nitrogen, after holding in vacuum for 60 min, and was cast in an iron mold. Melting in vacuum tends to decrease the amounts of gaseous elements. From the results obtained, it is concluded that the effect of the melting-furnace atmosphere on the graphitization is related to the change in the acid-soluble nitrogen content. In this experiment, however, the difference of melting-furnace atmosphere caused no appreciable change in the chemical components but nitrogen. If the amount of the elements except nitrogen was varied by differing furnace atmospheres, the graphitization would not be affected by the amount of acid-soluble nitrogen alone.