Grain refinements were studied on Cu-10%Al alloys by using various alkali metal salts and it was found that these salts could reduce the grain sizes. The most effective were sodium and potssium fluolides which reduced the grain size about one third of cast without them.
  The author confirmed the following facts in the case NaF was used as a refiner.
  1. By an addition of over 0.8% by weight of NaF, grain sizes were more refined.
  2. No undercoolings occurred in the cooling curves either NaF and Na₂CO₃ was added respectively or not.
  3. The refining effect of NaF decreases as time elapsed after its addition.
  4. Addition of NaF is also effective to Armsbronze alloys as a grain refiner and improved the tensile strengths and elongations.
  5. When the Cu-10%Al alloys were treated with K₂CO₃ and Na₂CO₃, the tensile Strengths and hardness were increased but elongation were decreased and got rugged fractures along the grain boundaries.
  6. Na was not detected even by the spectrographic analysis in the specimens of NaF addition.

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  Concurrently with the increased demand of ductile cast iron, its machining has swollen yearly. Recently, the basic research and investigation of the machinability on various metals have been carried out actively. Nevertheless, the data on ductile cast iron are few as it is a new material.
  In this report, the result of test of cutting force, chip formation and tool life on ductile cast iron are presented in comparison with the other materials including a trade competitor, namely, cast iron.
  The results obtained are as follows;
  (1) On cutting force ductile iron as cast nearly equals to cast steel, and full annealled ductile ironequals to blackheart malleable iron.
  (2) On chip formation, ductile iron is somewhat like black heart malleable iron and don't coil around the tool.
  (3) In cutting tool life test of full annealled ductile cast iron, adhesion takes place. Tool life become short in the ordering of cast steel, cast iron and ductile iron as cast.
  (4) On drilling tool life, black heart malleable iron is the best but both and tempered ductile cast iron and pearlitic malleable cast iron are inferion. In this a case the use of sintered carbide tools would be recommended.
  (5) The optimum cutting tools for pearlitic ductile cast iron were found out. They comprise three grades of sintered carbide; M 10, M 20 and P 20.

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  Cereal binders which have been used for foundry sands consist of three states, that is β-starch, α-starch and dextrin, but their properties were less investigated.
  In this report, firstly the testing method of classifying the kinds of cereal binders into three groups was investigate, subsequently the relation was ascertained between the properties of foundry sands were prepared by addition of the cereal binders respectively and each group of cereal binder which was classified.

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  When the amount of zirconium in white cast irons was less than 0.1%, zirconium accelerated the rate of graphitization in the annealing practice. This phenomenon was confirmed in three series of white cast irons made from commercial white irons of different origins, and ferro-zirconium or spongy zirconium. The irons without addition of zirconium, prepared by melting under nitrogen atmosphere have slower rate of graphitization than those under argon atmosphere. However, when the irons contained zirconium more than 0.03-0.04%, the change of the melting atmospheres, such as nitrogen and argon, made no difference in the rate of graphitization.
  From the result of thermodynamic calculation, zirconium in the irons seems to combine preferably with nitrogen than carbon, similar to the behavior of titanium found in the previous work. Therefore, since the amount of nitrogen which retards the graphitization decreases with adding zirconium, zirconium becomes a graphitizer.

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