It is well known that Ca-Si alloy is effective for spheroidizing graphite in cast iron. However, an excellent effect could hardly be anticipated in actual practice by an addition of the alloy alone. So it was investigated in details and it was cleared that Ca-Si alloy, when added to a molten iron, formed on the surface of the alloy the shell composed of α-Ca₂SiO₄ by air and CaC₂ by molten iron. As the shell has a very high fusion temperature, it prevented the alloy from contacting with a molten iron. The addition of flux to the alloy is, therefore, very effective for keeping the alloy from forming the shell having a high fusion temperature or for sweeping away the shell formed.
  Then the effects of various salts as a flux were investigated and the following results were obtained :
  (1) The fluorides were more effective than the chlorides of the same element.
  (2) Mg salts were most effective and Na salts and Ca salts were next to it in the order.
  (3) The composed fluxes that NaF, NaCl or CaCl₂ were fused respectively into CaF₂ were more effective than CaF₂ , base salt.
  (4) The effect of MgF₂ as a flux decreased by fusing NaF, NaCl or CaCl₂ respectively into it.
  Furthermore, the mechanism of the fluxes to promote spheroidizing graphite Ca-Si alloy was investigated. The results obtained were as follows :
  (1) The salt itself has little effect to the spheroidizing graphite.
  (2) The addition of Ca-salts with Ca-Si alloy is effective only for keeping the alloy from forming the shell having high fusion temperature or for sweeping away the shell formed.
  (3) In case of addition of Mg-salts with Ca-Si alloy, besides the above effect, Mg-salts help the spheroidizing graphite by following reaction :
  The salts react with Ca, which is isolated from Ca-Si alloy by dissolving Si-component of the alloy into molten iron, and set free Mg, producing Ca-salt.
  (4) Na-salts set free Na, which spheroidizes graphite, on the same principle, but the effect of the salts is weaker than that of Mg-salts, for Na has a high vapor-pressure at the reaction temperature.

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  Total shrinkages of pure aluminium and its alloys were measured preliminary on the castings of different rates of cooling, and then the linear changes of them were measured continuously according to the temperature of the castings as it cooled in the mould. The results were summerized as follows ;
  (1) Primary expansion before the end of the solidification is closely related to the internal pressure of the melt, which is susceptible to increase by the involved gas, by vapour pressure of the included metals of low boiling points and by the statical pressure of the melt.
  (2) As primary expansion is related to the separation of the gas in the melt, the expansion may appear in a few steps according to the changes of gas solubilities.
  (3) Since the contraction begins by the coherence of the crystals, the starting time and temperature of it varies with the content of dissolved gas and the form of crystallization.
  (4) The slope of the temperature-contraction curve within 100～150° below the starting temperature of the contraction is affected by the gas separation and by the form of crystallization. The slope is gentle when the gas separation is active or in the alloys of coarse grains.

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  In order to evaluate the quality of grey cast iron, Patterson recommended to investigate tensile strength against saturated carbon and Brinell hardness against tensile strength (Giesserei, 46 (1959) Heft 11). As it seemed to be quite reasonable, the authors tried to ascertain it with the test bars of 30mm dia. as cast collected from several foundries. Application of bending strength was also discussed.
  Microscopic structures were selected as the criteria for quality evaluation. That is, specimens were classified into three groups :
  1) Structures with A type graphite.
  2) Structures with E type graphite.
  3) Unfavourable structures.
  Reliability of each method was ascertained with the frequencies which the points representing each group are arranged in the graph in the order of above criteria.
  Among the various combinations those which were considered to have a reliability were following three :
  1) Bending strength against saturated carbon.
  2) Tensile strength against saturated carbon.
  3) Brinell hardness against bending strength.
  Brinell hardness against tensile strength is inaccurate. It is desirable to think much of bending strength since it is more reliable than tensile strength. In the case of using the bending strength, a criterion indicating the border line between good quality and bad quality are suggested as follows :
      σ_b=139.2－99 Sc (kg/mm²), H_B=35.8+3.2σ_b

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  This is a report on the new type shell molding machine which makes the shell by pressing the resin sand on the flexible sheet into the pattern mold.
  After the careful fundamental researches on this method, the new type full automatic machine was designed and manufactured.
  That machine is so efficient that the shell production is about sixty an hour, and the property of the shell is very precise and strong.

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  The present author investigated the wearing properties of various cast irons which was flake, spheroidal, eutectic or other shaped graphite structures. As the the opposite specimens, wormlike flake graphite cast iron was used, and the abrasion test was practed on dry condition. The present author can't be satisfied by the heretofore reported papers which discussed the wearing phenomena by using the total sum of wearing amounts, the specific wearing amounts per certain wearing distance, or the simple relation curve between wearing amounts and distance. The author analized the wearing phenomena by least square method, and drew some instructive features.

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