| 摘要 |
PURPOSE:To improve precipitation of abnormal graphite structure near the black skin surface of a spheroidal graphite cast iron by adding and incorporating preliminarily a prescribed amt. of Mg, Ca, Si and rare earth metal to a mold coating material. CONSTITUTION:A mold coating material is preliminarily added and incorporated therein, by weight, with 0.3-4.0% Mg, 0.1-1.0% Ca, 0.4-16.0% Si and 0.1- 1.0% rare earth metal. A spheroidal graphite cast iron is thus prevented from being precipitated with abnormal flake graphite structure near the black skin surface thereof. Such mold coating material is applied for production of a casting in the state of having a surface black skin part with which service strength is important. |
