The metal flow in fire-grate castings was investigated by the same means as stated in previous reports. The grate was cast horizontally or vertically through one, two or three gates respectively and the flow patterns for them were obtained. It is to be noted that the corner effect is rather remarkable for each casting.

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  This report concerns the theoretical and experimental researches on the distribution of the fluid metal by gate and runner.
  Metal can not flow in channel at fill up condition, therefore in this regards, there are some differences between theory and experiment, but the equation mentioned in this report shows approximate ratio of the distribution.

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  The original researches on the refining method of cast iron by the electrolysis of slag shall be stated hereinafter. Cast iron is not so easily reduced as steel, therefore strong deoxidizing reagents ; i.e. alkali, alkali earth metals and Mg are necessary to reduce cast iron melts satisfactorily.
  Charging positive voltage to slag and negative voltage to melt, the electrolysis was made on slag which covers the surface of cast iron melt, then the melt can be reduced and it resulted the nodular graphite structure.
  The condition of the electrolysis was 10∼30 min. at 1250°C∼1350°C.
  The slag which seems to be applicable to the refining method is such that the fluorides, chlorides, carbonates, oxides of alkali, alkali earth metals or Mg.

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    To clarify the effect of graphite-form and its distribution on grid irons, containing 3.5% C and 5.0∼6.5% Si, specimens were made by casting the Mg-treated iron in sand mould after it was held at 1400°C for several time intervals and then by the subsequent annealing.
    The results are as follows :
  (1) The spheroidizing effect is maintained longer time than in the case of common S. G. iron, probably due to the fact that some of the Mg atoms in the molten iron may not only be bound by C atom, but also be bound by Si atoms.
  (2) The specific resistance is raised irrespective of Si content, till 1.7 times of the value of the iron cast immediately after the Mg-treatment, by holding the melt up to 32 minutes.
    The degree of the decrease of the temperature coefficient due to the holding time becomes larger with the increasing of Si content. When both the specific resistance and the temperature coefficient are demanded to be small, the melt must be cast just before the formation of fine supercooled graphite occurs.
  (3) Grid properties can be estimated conventionally by the value ρσ₁/α, where ρ is specific resistance in μΩcm, σ₁ is statical bending stress in kg/mm² for 1 mm deflection and α is temperature coefficient of the electric resistance. The value ρσ₁/α becomes maximum at the holding time of 16 min. of the melt and it becomes larger when Si content becomes higher.
  (4) The burned structure formed by the annealing appears in irons having flaky graphite in the as-cast state, the area of the structure being enlarged by higher Si content.

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  The author has studied the properties of expansion and contraction of moulding sands at the elevated temperature and the result shall be announced in this report.
    In order to decrease the degrees of expansion of moulding sands at the elevated temperature, the following two methods are considered.
  1) Decrease moisture content in sands and increase the number of rams.
  2) Increase moisture content and the number of rams. (H. M.)

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