It is well-known that the aluminium-silicon system alloys have excellent cast ability and that the aluminium-zinc system alloys present high strength. Being given attention to these facts, the studies on the aluminium-silicon-zinc system have been carried out. In the present work, mechanical properties of the aluminium alloys containing 4∼25% zinc and 0∼20% silicon have been determined. The specimens are as-cast permanent mould castings.
  Increasing amounts of zinc and silicon develop hardness and tensile strength of the alloys, particularly when Zn + Si % is more than 20. But, increasing of tensile strength is limited by range of the composition. The alloys containing 13∼28% zinc and 6∼15% silicon above 100 Brinnel hardness and above 25 kg ⁄ mm² tensile strength.
  Addition of chromium enlarges the spheres of epui-hardness and equi-strength. Additions of manganese and magnesium are effective on strength of the alloys.

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  Drying method which is being thought to be most difficult in applying the stream line operation, can be remarkably rationalized and be highly efficient by adopting the high frequency heating method.
  Having a success in a fundamental experiment on the high frequency heating of molds and cores using synthetic resin binders, the author is now applying the mass-production of them.
  The following terms are summarized as its characteristics.
 1) This is suitable to a stregm line operation owing to its continuous heating.
 2) This cuts, to a great extent, the installation and the area, and is simply handled.
 3) Drying time is very much shortened, that is, 15 to 20 minutes in general.
 4) In the case of using resin binders, the characteristics of the high frequency drying method is remarkably emphasized.
 5) An uniform heating in spite of a size of mold, and non overbaking can be expected in this case.
 6) Cost of electric power used to heat is considerably lowered than the usual heating method.
 7) It is the weak point of this process that the initial cost of installation is high and there are delicate electric parts and dangers owing to trouble and defect. (Okakura)

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  The author with a new conception, advances his own theory on foundry which was continously studied from materials and coke to cupola operation, and further describes the development of a new manufacturing process for briquette coke and an ideal construction and operation of cupola.
  The author recommends :
  1) Foundry coke should have high elemental reactivity and most balanced characteristics of shape and hardness. Briquette coke generally meets these requirements.
  The author developed its new manufacturing process and succeeded in putting it on a mass production basis. A large amount produced by this method is now used in industry under the name "Tekken" or R. T. L. ( = Railway Technical Laboratory) coke.
  2) A cupola should be so designed as to produce high-temperature, non-oxidized molten metal and this with a constant rate from the start to the end of melting operation.
  To fulfill this requisite, the following specifications for the equipment are recommendable —
 a) Tuyère : single-row ; neither double-nor multiple-row is adequate.
   ⅰ) Ratio : a little smaller than generally aecepted value is taken.
   ⅱ) type : rectangular, nozzle type with breadth-length ratio, 2 to 1.
   ⅲ) Direction : to be arranged dow wards at 10-15°; slightly tangentially to the circumference in order to induce spiral draft.
   ⅳ) Inner diameter : to be widened toward the upper end so that the melting zone comes into a funnelled part.
 b) Height from tuyère to charging door : to be more than 4 times the inner diameter at tuyère level.
 c) Forehearth : no forehearth is preferable.
 d) Blower capacity : too large a capacity must be avoided for it entails difficulty of air adjustment.
  3) Coke ratio : coke ratio should be made as low as it is consistent with proper maintenance of molten metal temperature. For a 1 ⁄ 2 t cupola with low thermal efficiency because of small size, it should be raised to 15∼7% ; with increase of dimensions it can be lowered and 10∼12% is appropriate for a 3 t unite.
    4) Blast volume : Enough volume is to be blasted to secure full combustion of charged coke but even a little excess air shall not be allowed.
  Blast volume may be computed at the rate of 7 m³ ⁄ min per 1 kg of carbon content of the coke.
  5) Ignition : Bed coke should be so laid that every part of it can be uniformly red-heated.
    For this purpose, only when sufficient heat is generated by firewood stacked and ignited at the hearth bottom, coke should be charged in small portions to make sure that every charge is fully red-heated.
  6) Start of charging and blasting : After bed coke layer is built and the whole of it reaches a red-heat state, materials and coke are charged and blast is begun in 20∼30 min.
    For the first 10 min, 20∼30% more than scheduled volume is sent. When 200∼150 mm of bed coke is consumed, the volume is reverted to normal ; thus the temperature of the first top of molten metal can be elevated and operation goes on afterward with bed coke maintained at a cons ant level.

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  Metal solidification processes a key to solve the problems of gating & feeding, to avoid the shrinkage cavities of casting and to give the proper chill application.
  Solidification curves and times for metals were obtained at various pouring temperatures for many different size, conductivity, thickness and temperature of moulds.
  To establish be eperimental formula and to adjust the result, the dimentional analysis was used in this investigation.

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  This is prepared to report the series of the study on the recollecting method of molding sand published by the author several years ago.
  The previous study was of the dust exclusion method by the wind control which was best suitable to dry sand molding practice. But this method was not adaptable to green sand molding.
  This report is the result of the study on the dust exclusion method of green sand by the flutriation method.
  As to this method, being suggested by the mineral separator in mines, several step's gates were made on the way of stream, sand grains were deposited at each gate and only ultra-fines were removed with overflowed water.
  The apparatus in this report has a capacity of about four tons of sand a day. It requires about 8 cubic metres of water an hour.
  The results of the described treatment are as follows.
 1. A grain distribution of recollected sand deposited at each step of the gate has each high peak point.
 2. Compressive strength, permeability of sand and resistance for burning-on are remarkably improved.
 3. This method saves naturally bonded sand. It is shown by the author's performance of half a year that seventy percent of sand consumption lessened.
 4. Pieces of wood, stones and etc, in naturally bonded sand can be easily removed. This small device is suitable to a small and medium scale foundry, but the larger one ( 8 ton capacity a day) is being prepared as the mechanized. (T. Okakura)

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