高純度鋳鉄の真空溶解の研究

抄録

  In order to investigate the solidification process of cast iron, the solidification of high purity iron-carbon and iron-carbon-silicon alloys must be studied.
  A specially designed high frequency high vacuum melting furnace was developed to perform a series of experiments under a condition in which there will be a smallest possible influence from impurities and gases, and simplifying the factors influencing the solidification process and structure.
  To ensure nniformity of the samples in each series, about 500g of each raw alloy was prepared in a vacuum melting and casting furnace from pure graphite, pure silicon (with less than 0.1% of impurities) and electrolytic iron (with less than 0.1% of impurities). Approximately 50g of each alloy was remelted in an alumina crucible placed in the specially designed high vacuum furnace. The specimens were kept at various temperatures for a given period and then cooled at various speed.
  From the results of a few experiments with this apparatus, it is concluded that the experimental conditions such as temperatures, period and cooling rates can be strictly controlled. This apparatus was found to be satisfactory for experiments of the solidification of cast iron from observation of the solidification bahavior and the thermal analysis curves. In hyper-eutectic alloys, the primary graphite crystalization was observed directly on the surface of the samples.