The authors investigated the invading depth of steel poured into the melt in a mold by a model experiment to find some physical and hydrodynamical properties of molten steel.
  The results obtained were as follows.
  1) The invading depth of pouring steel into the melt was presumed to be so deep as to give an influence to rather an extensive range; it caused more possibility of inclusions, sand marks and blowholes.
  2) The invading depth was increased with increasing the head and the diameter of a nozzle, and especially it was influenced by the former. Therefore it was important to decrease a head as possible for producing sound ingots and castings.

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  An analysis on the influence of pouring rate upon the solidification mode in bottom gated castings was carried out by using experimental results obtained in conventional cast irons and ductile cast irons.
  The influence of pouring rate on the solidification mode was semi-quantitatively explained by the proposed equations introduced from a point of view in which the main factor in the change of pouring rate did not act on the temperature distribution of the melt but on the locational difference of heat extraction rate by mould.
  In the present paper, the law of similarity on the relationship between the dimension of castings and the pouring rate was also investigated by using the proposed equations and the experimental results.

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  Grey cast iron for the construction materials of machines often suffers to be exposed to high temperature. In this case, it is considered that the graphite in grey cast iron is affected by a certain state of heat in a thermal zone, therefore the firing temperature of graphite in iron was estimated by a thermo-balance and the combustion process was examined.
  The extraction of graphite in cast iron has commonly performed by some methods of chemical, electrolysis treatments and others. Adopting the chemical treatment, authors studied the combustion process of the graphite extracted from several cast irons in air and in oxygen atmospheres, the behaviour of impurities accompanied with the extracted graphite was investigated by the method of JACO X-ray spectral analysis.
  Then the following results were obtained :
  1) The firing temperature in the combustion process becomes low as follows; Flaky graphite system→Nodular graphite system→Fine eutectic graphite system.
  2) The amount of the residue after combustion shows the same tendency to the firing temperature given above.
  These are caused by the kinds and the quantities of the impurities accompanied with the extracted graphite.

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  Many publications have described on the embrittlement of black heart malleable iron. It has been clarified that the increase of phosphorus content in the iron raise the transition temperature of ferritic malleable iron. Besides the addition of copper or molybdenum showed a useful effect to prevent the tendency to happen the embrittlement which occurs especially when cooled rapidly from the temperature of critical range, e.g. 450 to 500°C depending upon its chemical composition.
  With a view of investigating the effect of addition of copper and molybdenum to two kinds of irons having both low and high phosphorus content, the charpy impact test of these series of iron has been carried out at low temperatures as 0, −15, −30, −45, −60, −75, −100 and −196°C. Seven test specimen finished from shell mold castings were used at same condition. Results obtained in this study are as followings :
  1) The increase of phosphorus lowers the impact value. Also the lower the impact test temperature, the lower the impact resistance. The transition temperature of the iron is raised gradually by the increase of phosphorus addition.
  2) No remarkable effect of copper addition on impact resistance at low temperatures was obtained. Whilst the addition of copper as 0.5 to 1.5% lowers the impact resistance to some extent, the iron having higher copper content as 2.0 to 2.5% shows no such deleterious influence.
  3) The addition of molybdenum under 0.5% improved markedly the impact resistance, especially at low temperatures.
  4) On the iron having higher phosphorus content as 0.127%, no better influence was observed by the addition of higher copper as 2.5%, or molybdenum as 0.3%. In these iron series copper addition showed rather deleterious influence.

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  In view of the fact that casting method of thin grey iron is one ot the important subjects at present, the investigation was done on “Charcoal box-irons for export” and “rings for setting cauldrons on ovens” out of many thin section grey iron castings produced in Kuwana District, where they have had so much experiences in this field of casting for more than 50 years.
  By studying the foundry methods of them the datas and the production methods on the thin section grey iron casting were obtained. Reasons for selecting these two products are as follows: Both of Them are moulded with natural green sand, but each has the following antithetic features, i.e., a charcoal box-iron is of case-type, (about 3mm thickness, its three dimentions about 200mm×100mm×80mm) is gilded after polish. While a cauldron-ring is of very slender flat ring type (thickness: breadth: circular length=1 : 13 : 290∼1 : 20 : 1,100), and the producers have been making the utmost efforts to make them as thin and light as possible.
  The results were as follows :
  1) Permeability of sand mold should be kept particularly as high as possible in such thin castings.
  2) Moisture in raw sand was found to be 10∼13%.
  The percentage seemed to be too high at first, but from the results of laboratory experiments this amount was proved to be effective for good permeability, high strength of mold and better efficiency of molding processes.
  3) As natural green sand is insensible to moisture variations and low in price, it is a reasonable management to renew the sand which strives to diminish defects of casting and to cut down the production cost.
  4) Charges for cupola are restricted to pig irons and return scrap of these own products.
  Pouring temperature is kept at more than 1,450°C and 1,480°C for box-irons and cauldron-rings respectively.
  The charge compositions and the high pouring temperature improve the flow of molten iron.
  5) Gating and pouring systems can tolerably be addapted to several well-known experimental formulas on casting design.

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