PRODUCTION OF AS CAST FERRITE TYPE SPHEROIDAL GRAPHITE CAST IRON

摘要

PURPOSE:To obtain the titled cast iron from inexpensive main molten raw materials by adding iron oxide or iron ore and removing Si and Mn efficiently at the specific timing of producing base melt by using the molten raw materials of high Si and high Mn. CONSTITUTION:In the temp. range from right after melting down of main molten raw materials of high contents of Si and/or Mn up to 1,400 deg.C, iron oxide and/or iron ore are added to said molten metal to oxide and remove Si and/or Mn. Here, the timing of addition is extremely important in removal efficiency; if it is before melting down, the hanging of the molten materials occurs and this makes the continuation of melting work difficult. In addition, the molten metal under the bridge overheats and damages the furnace. On the other hand, above 1,400 deg.C, the reaction of C+O CO in the molten metal goes active and the removal of the Si and Mn by the iron oxide is insufficient. In this way, the base melt of low Si and/or low Mn is obtained and ferrite type spheroidal graphite cast iron is obtained in an as-cast state by using this.