Following the results of previous experiments, made by others interested in this field, on the deoxidation effect of high-temperature melting of cast iron, we carried out some fundamental experiments on the effects of Ca-Si inoculation using normal laboratory apparatus and processes.
    Using low P pig-iron in market or synthetic pig-p iron prepared from electrolytic iron and charcoal, we studied how the conditions of inoculation ; the constituents of raw materials, metal temperature for inoculation, quantity of the inoculant and time interval from inoculation to pouring, affect on the microstructures and the mechanical properties of so-treated pig iron.
  Some results obtained are as follows :
 (1) Ca-Si inoculation at least 0.3% is necessary for the improvement of microstructure, while 0.1% inoculant is satisfactory for decreasing chill depth. The effects of inoculation disappear in about 10 to 15 minutes after inoculation and this may be considered rather rapid.
 (2) The influence of Ti and Mn in raw materials on the effects of inoculation can not be neglected.
 (3) Superheating of melt and increasing of Mn content are effecteve for obtaining small-sized and uniformly distributed graphite features.
 (4) An Si increase and a slight S decrease were noted : however, a considerable increase in N₂ and a decrease in O₂ were observed.
 (5) The improvement of mechanical strength of pig iron by inoculation is obvious especially when Sc and P are low ; on this ground, the greater part of the charge metals should be steel scrap in actual melting operations.

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  The metal flow in handle castings was investigated by the lamp method same as before. Gate was attached tangentially or normally to a handle ring at the root of a spoke or between the spokes.
  The flow patterns of these are shown in figures. Generally speaking, metal fills up the casting rather quickly when the gate is attached normally to the ring or to the root of a spoke.

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  This is the report succeeding to two previously announced. And this time, the effect of the size of cast-in mild steel insert on the structure of the reinforced cast iron was investigated and the effects of the eccentricity or the position of the inserts on the possibility of soldering and structure and etc. were also studied.

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  The various properties of the so-called grid irons can be improved by the graphitization-treatment followed by quenching at 820°, wherein the iron contains 5∼6% of Si and 1∼2% of Cu. The electric resistance becomes higher, while its temperature coefficient becomes smaller, and also the corrosion resistivity against dilute HCl becomes better. It was found that even when ferrite dissolves silicon, it can dissolve as much as 1.5% or more copper simultaneously. Both the attitude that the solid solution of copper into silico-ferrite and that the decomposition of cementite into graphite contribute to the above improvement.

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  By the similar method with A. F. S. or Gakushin, the author has measured the main properties ; such as permeability, mouldability, refractoriness and strength, of molding sands produced in Niigata-Ken.
  Then, the properties of the sands were compared with that of the sands which are actually used in our foundries.
  The main purpose of this investigation is to make up synthetic sands from these sands.

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