In the proposed scavenging casting method, air or argon, which is an innert gas, is let in on the contact part of the surface of the molten metal to mould surface which successively rises at the time of casting to cause an air current with a definite direction.
  Then the gas infiltrated into the molten metal by low gravity pressure is brought out from the mould, instautly and successively, by means of the gas carrier.
  The present method is found to have such advantages and disadvantages mentioned below.
  1) It will not be applicable to such a mould having an extremely unsatisfactory ventilating property.
  2) It is practically useless against blow holes caused by the gas contained in the molten metal.
  3) Green sand mould may be utilized efficiently as sufstitute for dried mould which has been used to avoid blow holes.
  4) The flow of the molten metal can be inproved.
  5) Better casting surface, with fewer blow holes or pin holes, may be obtained in 13 Cr stainless steel or in low carbon steel, which is conventionally considered to be inappropriate for shell mould.

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  The object of this study is to achieve the economy in power consumption and the reduction of the operation in the practice of 2t basic electric furnace. The main improvements of this research are as follows.
  (1) Improvements were done on the method of repairing the furnace.
  (2) A new oxygen-injection process and a method of preheating the metal by crude petroleum mere performed.
  (3) Determinations were made on the proper size and quantity of the charging metal and the slag materials for one charge.
  And in this way the rational operation of the electric furnace was proposed.

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  In the studies of its heat-resistance of S-H cast iron, it is already reported on the advantages of its growth-resistance. This time, the authors carried out some investigations on the properties of oxidation-resistance. The oxidation degrees were measured by weight increase, employing a sort of thermal balance formerly designed by Dr. Honda.
  Speciments employed were as follows: coarse flake graphite cast iron, common grade gray cast iron, special pearlitic cast iron, nodular graphite cast iron and S-H cast iron.
  The speciments were repeated heating and cooling continuously between 600° and 920°C at 10°C/min in some cases and kept at 900°C for 5 hours in other cases.
  The results obtained are as follows;
  (1) The weight increase of S-H iron seems to differ according to the compositions. In general, weight increase is most in cast flake graphite cast iron and more in common grade gray cast iron and in special pearlitic cast iron than in nodular graphite cast iron.
  (2) Microscopically the thickness of the decarburized layer of ferrtieis, proportional to the tendency of weight increase.
  (3) Provided that carbon and silicon are kept at the same percentages and mangan increased, or that carbon and mangan are kept and silicon increased, the oxidation-resistance of S-H cast iron is also proportionally increased as similar tendency.
  (4) S-H cast iron holds almost the same heat-resistance as special pearlitic cast iion and nodular graphite cast iron, and the more heatresistance of it will be gotten by controlling the chemical compositions such as silicon and mangan.

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  An attempt is made to deduce a solution to the problem of gas absorption in the aluminum bronze. The molten metal absorbs hydrogen in the alternative way. The cast surfaces have characteristic appearances both microscopically and electron-microscopically depending on the treatments for gas pick-up. The metals free from any impurities or contaminated with such an element as beryllium that has a stronger affinity to oxygen than aluminum and forms the protective oxide film absorb hydrogen during direct exposing to hydrogen. “Steam reaction” results in little gas pick-up in these metals. The protective films of γ-Al₂O₃ and BeO formed over the metal surfaces are identified. On the other hand, aluminum bronzes contaminated with such an impurity as calcium that has a stronger affinity to oxygen than aluminum and forms no protective film absorb hydrogen during the steam reaction. The contamination of calcium as little as 0.5% results in the formation of the particular crystalline substance pCaO·qAl₂O₃ or pCaO·qAl₂O₃·γHO restraining the formation of alumina.

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  Mechanical properties of steel cast centrifugally had been reported under the rotating conditions of G≦152, and in this paper the author has investigated the changes of them at G>152.
  The results obtained should that the mechnical properties got worse in the range at G>171 of this investigation of G=152∼192.
  The mechanical properties were improved on annealing by increasing the annealing time but they got down as well at G>171.
  Moreover, by microscopical observation of the cross section of the test piece, it was found that the carbon segregated more by increasing the rotating speed of the mould.
  It seems to be true that the inferior mechanical properties at G>171 (N>1700r.p.m.) might be due to the severe segregation of carbon and other elements mentioned above as well as in the last report¹⁾.

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