Experiments have been performed on the effects of moisture in blast on the condition of cupola operation and the quality of the molten iron.
  As for the experimental procedure a dehumidifier which absorbs moisture in the blast is set between the cupola (int. dia. at tuyèrezone: 500mm, standard melting rate : 1t/h) and the blower. The dehumidifier is consisted of silicagel (4#) packed into a cylinder of 1350mm dia. and 500mm length. The wet air is brought from the upper side of the dehumidifier and the air is dehumidified while it passes through the silicagel. Wet air of 14g/m³ moisture can be made to lower than 5g/m³ moisture by this apparatus. Experimental blast containing more than 25g/m³ moisture is made by blowing steam into the blast. The effects of moisture in the range from 4.5g/m³ to 36g/m³ can be examined by this procedure.
  The experimental results are as follows :
  (1) Tapping temperature decreases with increasing humidity in the blast, and this tendency becomes remarkable when the humidity is more than 15-20g/m³. This may be due to the fact that the moisture, entering the furnace, contacts with coke of high temperature and a part of it is decomposed with the endothermic reaction.
  (2) A consideration on the tapping temperature, mechanical properties and other casting conditions suggests that the dehumidified blast is effective to stabilize the operating condition of cupola.
  (3) With increasing humidity in the blast, T. C in the molten iron decreases slightly and the losses of Si and Mn increase. This may be because of the fact that the compositions of the molten iron are oxidized by the moisture directly. P and S are observed to increase.
  (4) With increasing humidity in the blast, tensile strength and hardness increase a little but deflection decreases slightly. Mass effect becomes considerably large, thus, the material is deteriorated.
  (5) A consideration on the tapping temperature, mechanical properties and other casting conditions suggests that the dehumidified blast is effective to stabilize the operating condition of cupola when the original humidity in the blast is not more than 15g/m³.

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  As the first problem of the casting design, we made the experiment and observation practically on the relation of the material quality of cast irons to the fluidity, and of the pouring time to the castings.
  We melted irons by 5t balanced hot blast cupola, and made the study of the above mentioned with the eutectic degree between 0.7 and 1.1.
  We made this investigation for the purpose of the quantitative study of the fluidity of the iron after making the practical fundamental study, which was considered the primary element of the casting design.
  The following results are obtaind :
  (1) We made a spiral narrow cavity, and carried the practical daily control test of quality. The result was thought to give an important factor for the determination of the casting design.
  (2) We studied on the ordinary hypo-eutectic iron (inoculated iron) of Sc=0.7～1.0 and obtained the valuable results as the help for the workers in the foundry shop.
  (3) We established the following empirical formula about the pouring temperature, the chemical composition and the spiral lengths :
                L=83CEF+0.425T－826.5
  (4) When the iron composition was Sc=1, the spiral length became 100cm at the temperature of about 200°C above the beginning of solidification. Taking the above condition as standard, we named the ratio of the spiral lengths the coefficient of fluidity.
                   That is : K=0.01 L

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  The investigation was performed to find the movement of the molten aluminum in a vertical column before solidification as well as the feeding and the solidifying of it.
  The pure aluminium was cast at 750° or 700° to the green sand mold described in Fig. 1 with gates and risers shown in Fig. 2～Fig. 8 respectively.
  The location and the dimension of the gate had an influence upon the movement of the molten aluminum such as mixing and vertical circulations, which was measured by an oscillograph.
  The riser was also discussed by measuring the temperature of the metal besides the macroscopical observation of the casting.
  The results are summarized as follows ;
  1) With top gate, the running metal from gate at higher temperature dives into the cooled bottom part of casting, while with bottom gate, the running metal of high temperature pushes up to the top of the casting partly by convection ; the directional solidification would not be anticipated in the column by these gating systems.
  2) Comparing the casting obtained with top, bottom and step gate systems, the shrinkage cavity in it is minimized when the metal is poured with lower temperature in the top gate system.
  3) When the riser happens to be filled up with the cooled metal, the effect of it will be diminished, so it is desirable that the riser is filled with hotter metal and the mold walls of it is preheated by the flowing metal.
  It is found that the O'Conner riser is very effective and still effective even it is smaller than the calculated size by Caine's formula.

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  The present paper involves the contribution of end and middle chills to the sound areas in the castings of tin bronze, high strength yellow brass and aluminium bronze. Application of the end chill to cast plates leads to appreciably extended sound area at the end. Such sound area is so extended with enlarged size of chill that the depth of sound area is represented by 2.7 √x mm. in 88-8-4 bronze and 6.5 √x mm. in high strength brass (x is thickness of chill). The high strength brass has usually more extended sound area than the tin bronzes, since the former is rarely feeded during freezing than the latter.
  The sound area is also formed at the both sides of the middle chill. This area is appreciably extended toward the gate than in the opposite direction. Particular chill material has its own chilling power, and a cast iron block has more stressed power than a carbon block by 20%.

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  Plaster moulds produced some cracks or destruction on the surface of mould when molten metals were casted. We studied these phenomena by measuring hot strengths, hot deformations and shock heating cracks of moulds. The results are follows :
  1) Cracks of plaster mould were taken place by shrinkage of gypsum on heating. These cracks are different from scabs caused by thermal expansion of sand moulds.
  2) This defect was decreased by addition of some cushion agents which increase thermal expansion of moulds, for example, asbestos caused good effective results. Permeable plaster mould has large thermal deformation, and so good result is produced by no use of any cushion agents.
  3) By the addition of two or more cushion agents, plaster mould has better properties.

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  Recently synthetic sand is much used in the foundry industry. Synthetic sand has both high green and dry strength. On the other hand, it has the defect that it dries easily and the mould surface becomes rough and brittle, especially the corner. The stability of sand mould surface is measured by means of a scratch-tester, which was specially made by the investigators for this purpose.
  In this experiments, following results were obtained ;
  (1) β-starch which is insoluble in water and non-swelling, is not effective to the stability of mould surface.
  (2) α-starch which is insoluble in water, and swells remarkably, has good effects on the stability of mould surface. When mixed with water, it shows high viscosity. Owing to the high viscosity it is not easy to mix with the sand.
  (3) Dextrin is soluble in water. It has very good effect on the stability of mould surface. When mixed with water, the viscosity is low, and it is easy to mix with sand.

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