Copper or iron base alloys containg aluminium were difficult to cast as they were covered with oxide film on the surface; their fluidities were rather poor.
  The experiments were attempted to improve the fluidity of these alloys containg aluminium by coating the mould surface with chrolides, fluorides, carbonates, or sulfides of K or Na.
  These fluxes were spattered 0.2, 0.5 or 1 g on the mould surface, or water solutions saturated with the fluxes were used.
  The results showed that some improvements seemed to be gotten by these treatment.

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  The shrinkage of cast iron is affected by many factors such as raw materials, melting and molding conditions, and each effect of these factors has already been studied by previous investigators. However, the best preventive for shrinkage cavity has not yet been established in practice referring to all these factors.
  In order to clear the effects of all these factors and to establish the standard casting practice in iron foundry, the shrinkage characteristics of cast iron was examined on the specimens prepared in Tamman furnace, by means of orthogonal array design, H_3.81.
  The results obtained were summarized as follows.
  (1) The volumetric solidification shrinkage is proportional to the melting (and casting) temperature.
  (2) Shrinkage cavity is much decreased when the additional amount of the foundry pig is increased to 40 percent.
  (3) Carbon and silicon give no effect on the shrinkage characteristics when chemical analysis is kept in the range of FC 20.
  (4) The effect of phosphorous is not so clear, in the experiment considering all factors in the experiments.
  (5) Oxydizing property of slag increases the shrikage cavity vemarkably.
  (6) In the experiments where the additional amount of foundry pig as well as the melting temperature are considered, shrinkage cavity is reduced by increasing the additional amount of foundry pig to 40 percent, even if the melting temperature is as high as 1500°C.

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  “Z” point, the intersecting point of the extension of the liquidus curve DC and that of the solidas curve IE in the equilibrium diagram of Fe-C system, is of significance on the spherodizing of graphite in hypoeutectic cast iron. Let the extension of the other liquidus curve BC be CR. Melt supercooled to the area between CZ and CR must be supersaturated with both carbon and iron. On the other hand, as are well known, separation of carbon from supercooled melt is rapid, While separation of iron from it is not so rapid, and the melt should be readily supercooled. Then it follows that;
  1) In the cast of hypereurectic cast iron granular graphite precipitates before the repulsive force rises.
  2) In hypoeutectic cast iron with composition between C and Z the repulsive force rises soon, when the melt is supercooled. Then carbon and iron must precipitate at the same time, that is the eutectic reaction takes place. So spherodizing of graphite is difficult in this case.
  3) In hypoeutectic cast iron with composition between Z and E, melt may be supercooled readily, because the repulsive force does not rise, even if the melt is supercooled. Thus supersaturated solid solution “γ_m” with the same carbon content as the melt may be formed, and “γ_max” with the maximum carbon content is obtained at the “Z” point. The carbon content being too high in “γ_m” especially in “γ_max” carbon precipitates very rapidly, and results in the formation of granular graphite.
  The situation of the “Z” point in the diagram assumed to be at about 3.2% carbon equivalent and 110°C lower than the eutectic point.

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  This work was an attempt to explain the relations between the factors on the growth of cast iron, and to obtain the fundamental theories on the growth characteristics. Referring the changes of graphite structures in cast iron during cyclic heating, it was found that the growth is a metallurgical phenomenon concerning to the re-distribution of graphite by the repetition of diffusion and precipitation. The results obtained were summarized as follows:
  (1) The growth of grey cast iron is due to a irreversible expantion occured through the solution and separation of graphite during cyclic heating.
  (2) Diffusion of carbon from graphite through the matrix contributes to growth, and the volume changeis nominal remaining porosity after graphite solution and contributes to re-distribution with separation.
  (3) As no transformation appears in the heating cycle, the phenomena of growth in austenite region could not be explained by the previous theories, but the present conceptions on graphite re-distribution makes it possible.
  (4) Growth in cyclic heating over the critical range is a sum of growths in the austenite region and the transformation, which were not examined separately.
  (5) Some factors give different effects to the growth in austenite region and in critical range, because the mechanisms are different in deposition and solution of graphite. Influence of heating atmosphere in air effects indirectly in the early stage of heating by gas absorption and then becomes directly by internal oxidation.

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  In basic cupola, it is supposed that there are following advantages which are favorable to obtain nodular graphite cast iron:
  1. High absorption carbon.
  2. Charge of more steel scrap.
  3. Low sulphur content of molten iron.
  4. Low melting loss of Mn-content.
  5. High tapping temperature.
  Then, the effect of Ca-Si to the molten iron was investigated in a experimental basic cupola. The results obtained are as follows:
  1. By adding 2.5% of Ca-Si with 1.5% of CaF₂ nodular graphite cast iron was not be obtained.
  2. By adding 2.5% of Ca-Si with 1.5% MgF₂ to the molten iron of low phosphorus pig iron, a perfect nodular graphite cast iron was obtained even in the early operation stage.
  3. Even in case of the melt of a synthetic pig iron (a low grade iron), a perfect nodular graphite cast iron was obtained by adding 2.5% of Ca-Si with 1.5% of MgF₂ except in the early stage.
  4. By adding 2.5% of Ca-Si with 1.5% MgF₂, a molten iron was desulphurized more than 80%.
  5. It was certified practice that the sulphur content of a molten iron should be less than 0.02% to obtain a nodular graphite cast iron.

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