Abstract
In special steel castings using sand mold, the occurence of penetration largely depends upon the kinds of adding metals and simultaneously their contents.
In this report, studies were directed towards to chromium steel and manganese steel especially. In chromium steel, in general, thin film of Cr2O3 is apt to produce on casting surface in mold during metal pouring. These film of Cr2O3 should prevent the penetration at the surface of castings.
Therefore, it can be concluded that the higher the chromium content the less penetration occurs in chromium steel castings. While in manganese steel casting a glass composing MnO-FeO-SiO2 is produced easily, and the penetration occurs in no relation to manganese content.
