The relation of blast quantity and combustion ratio on cupola operation has been studied. The experiments have revealed the following:
  (1) From the blast quantity, cupola operation is divided in two groups which are: (1) the operation with air input below and (2) above the critical blast quantity.
  (2) Under constant operating conditions except blast volume in the former case the iron temperature increases with an increasing blast input but the combustion ratio is held constant. In the latter case, however, with an increasing blast input there occurs the increase of combustion ratio and the drop in iron temperature.
  (3) In the former case, blast volume has to be controlled at constant value, but must not be adjusted with the change of combustion ratio. In the latter case, blast volume may be adjusted with the change of combustion ratio.

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  With the view of elminating the various defects in white iron casting containing high manganese as 0.85 to 1.10%, the compelled oxidation and reduction refining of molten iron from cupola were carried out in Heroult electric arc furnace with acid lining. As the results of using this type of melting operation, the as-cast fracture of white iron castings showed neither mottling tendency nor pinholing defects which were often found in the castings melted by ordinary duplex melting process. In this case, however, post aluminum deoxidising treatment has no effect on the mottling occurence in white iron castings.
  Trial production melting and annealing have shown that high manganese content in white iron made it possible to obtain pearlitic malleable iron having laminar pearlitic matrix along with standard black heart malleable iron by continuous furnace annealing.
  On the other hand, granular pearlitic malleable iron were also manufactured with ease by heat treatment consisting of first stage graphitisation followed by rapid cooling and short time tempering.
  It is also clarified that pinholing defects occurring when the molten iron treated with manganese in ladle was poured into green sand mold, were reduced comparatively by adding special reagent as borasic acid into facing sand of the mold.

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  The sliding wear phenomenon on the lubricating state of the titanium cast iron with eutectic graphite structure was studied. The effect of the wear caused by the contact pressure and the frictional velocity were made clear, and its wearing tendency was studied the under mechanical stable condition. The mechanism of the wear was investigated by means of the electron microscope and some other methods.
  It was found that the titanium cast iron with eutectic graphite structure is extremely good at the wear resistance under the lubricating state, which may be explained by assuming that minute grains of graphite are distributed uniformly in the perlite matrix.

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  The present paper describes experimental results on contribution of the padding and the characteristic mode of freezing to form the sound area in the casting of several metals, such as commercially pure aluminum, high strength yellow brass, tin bronze and steel. The bar and plate castings which were of 220mm length and variously tapered linearly from end to riser were tested, and from those results discussions were given on the critical padding about each alloy and casting shape.
  Considerable increase in sound area was obtained with relatively small padding in the skin formation type alloys, such as pure aluminum and high strength yellow brass. On the other hand, the increase of sound ares could not be expected in the castings of mushy type alloy such as tin bronze.
  In the case of tin bronze, it is rather desirable to avoid padding because the mechanical properties were made worse with the increase in thickness of castings.
  Estimating the effect of degree of padding in each casting shape, less degree of padding was sufficient to obtain enlarged sound area in plate than in bar. Linear relationship was found between the critical padding and the critical temperature gradient, therefore the former may be decided by obtaining the latter experimentally.

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  Oxidation of the molten 85-5-5-5 red brass which is a correlative problem with the dissolution of reducing gases has been studied by means of the fracture test of chill-blocks, centrifuging, electron-microscopy and X-ray diffraction.
  The process of oxidation of the melt includes following three steps; i) oxidation of the reducing gases in the metal, at this step the cast-block has the extended columnar and blue-grey patterns on its fracture: ii) preference oxidation of an alloying constituent such as zinc, where, further shortened columnar and blue-grey patterns are formed on the fracture of cast-block: and finally, iii) formation of Cu₂O simultaneously with oxidation of zinc, at this step the cast-block has markedly reduced size of the equiaxial grains. The nucleating cuprous oxide is also identified.

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  Results of the study conducted on vacuum sampling method are given. The method is almost perfect and comparatively simple in operation.
  The sampler for vacuum sampling method is as shown in Fig. 1 and photo. 1.
  In case of determining hydrogen content in molten pig iron in the ladle, vacuum sampling method which is different from casting method and has generally shown lower values, because of gas released during solidification of molten pig iron in the sample case.
  The gas evolved during solidification of molten pig iron in the sampler of vacuum sampling method is caught at the upper part of the sampler and found in analysis.
  In addetion casting method is affected by atmosphere, but vacuum method is not affected.
  The vacuum sampling method is very good theoretically and easy for daily operation as compared with previous other methods.

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