The clay substance which is added to the molding sand in the mold as the binder turns into plastic state when steel or cast iron is cast. When a substance is deformed in plastic state, the compressive stress varies with the compression rate.
  In this paper, the relations between compressive stress and compression rate are investigated using the specimen of foundry sand bonded with bentonite.
  As the result, it is found that the compressive stress of the sand specimen is remarkably improved with the increase of the compression rate. The effects of the second binder is also investigated.

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  When observing a natural flow, falling down from a nozzle, it can be seen that the stream falls continuously for a certain length. Then it deforms gradually and at last it is broken into pieces. It is necessary to consider this phenomenon when designing shower gate.
  If the broken stream strikes against the surface of the lower liquid, there takes place a violent collision, therefore, it is desired that the stream reaches the lower liquid surface as a continuous flow. Thus a plan to extend the continuous flow should be taken, and the shape of shower gate may have a great concern with such the plan.
  The length of continuous flow was determined by shower gate with 170mm head. The outlet diameter of the shower gate was 10mm and its length was 30mm. The corner radius (r) of the inlet and the taper of the gate wall were varied. Gray cast iron and Wood's metal were used for the melt. Casting temperature of the former was 1350∼1400°C and that of the latter was 110∼120°C.
  Experimental results suggest that the increase of the corner radius of the inlet is most effective in order to increase the length of continuous flow. When the radius is small the flow is checked at the inlet and the length of the continuous flow is shortened. For instance, in the pouring of molten cast iron, the following results were obtained:
        At r = 0mm, length of continuous flow = 530mm
        At r = 25mm, length of continuous flow = 1070mm
  The taper of the side wall of gate produces good results to some extent but not surpass the effect of the corner radius. This is because the stream after running out is checked by the taper, so that there should be some parallel portion at the outlet.
  Many foundrymen set shower gate at such a position that the melt may flow down in contact with the vertical mould wall, for the purpose of letting the stream run down quietly. However, it is supposed that the falling stream is impossible to touch with the wall as it gradually becomes thin. To make sure of this condition, electric terminals were set at points of 40, 100 and 170mm distance from the outlet of the gate, and the degree of the falling stream contacts with the wall was examined. The taper of the gate was varied in order to obtain good contact. The results show that most streams contact with the wall at the upper point but do not contact at the lower point. And only at the middle point a little influence of the taper appears. When one side taper is ¹⁄₃ or ¹⁄₂ the most favorable state is obtained. But such an effect is not sufficient and after all it is concluded that the falling stream is difficult to contact with vertical wall. Moreover, the gate of this type may cause the wash of mould surface. So that it is recommended that the shower gate should be set at the position apart from the wall.
  Comparing the flow conditions of gray cast iron and Wood's metal, the length of the continuous flow of the gray cast iron is larger than that of Wood's metal, and the former is more difficult to contact with wall than the latter. This may be due to the fact that the surface tension of cast iron is stronger than that of Wood's metal.

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  The kinds of titanium compound and graphite shape, etc., were studied in normal cast iron containing titanium and nitrogen. The results obtained are as follows:
  (1) Titanium in cast iron combines with nitrogen in iron at first, and, after all nitrogen contained converts to TiN, excess titanium forms TiC.
  If atomic ratio Ti/N is over than 4, TiN disappears and TiC exists alone. TiC may solid-solute nitrogen,
  (2) In the chemical composition range of TiN alone, the shape of graphite is flaky, and, when TiC appears, eutectic graphite exists partially. All eutectic structure is gained when all titanium compound is TiC.
  (3) Tensile strength and hardness of iron are somewhat low in the area of two compounds, and they are pretty high in the area of flaky graphite alone or eutectic graphite alone.

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  It is not easy to make sound castings of spheroidal graphite cast iron, because of their large shrinkage during solidification. For the remedy of these shrinkage defects, large risers, shrinkers or exothermic materials should be applied to the castings forming shrinkage voids at the upper part of the casting. In recent years, spheroidal graphite iron castings treated with calcium or calcium-silicide are said to have less contraction than magnesium treated iron castings on the standpoint of iron founders.
  In this report we compared many cast specimens treated with various sphroidizing reagents, such as pure magnesium metal, calcium-silicide, OZ spheroidizer and mixture of calcium-silicide and rare earth oxide. The shape of cast specimens was riser and weight type. On these specimens we examined the volume and the height of shrinkage voids and the damping property tested by a ultra-sonic inspector.
  The following results were obtained.
  1) Spheroidal graphite iron castings treated with the reagent of calcium-silicide mixture have less shrinkage than magnesium treated iron castings.
  2) The reason may be because of the fact that the magnesium treated iron has less graphitizing property than the iron treated with calcium silicide mixture.
  3) Use of exothermic materials or rice straw ashes on risers of castings has good effect on making sound castings.

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  This paper presents a study of the influence of normal elements on the S-curves for cast irons containing 0.4 to 0.6% molybdenum and 1.2 to 1.5% copper. The behaviores of isothermal austenite transformation after austenization at 900°C for 30 minutes, were investigated by microscopic examination in pearlite transformation range and by dilatometric measurement in bainite range.
  The influence of carbon or silicon content on the rate of transformation in the pearlite range was comparatively small, except the acceleration of lower pearlite formation in high carbon iron with coarse flaky graphite. In bainite range, on the other hand, the time required for the beginning and ending of the transformation was markedly shortend with increasing corbon or silicon content. Phosphorus moved the position of the S-curve in pearlite range to the left, and in upper bainite range to the right slightly. In both ranges of pearlite and bainite, the transformation was restrained by manganese, but remarkably accelerated by sulphur.

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  This paper is a record of the work on our cupola plant to consider the technical advantages from the use of water cooled cupola. In general, the economic efficiency of the plant is very dependent upon the method of melting. Therefore, more attention is given to the problem of water cooling of the cupola. We obtain the details from experimental work and with this result the cupola is designed and installed. The results from the operation are summarised as follows:
  Greater uniformity melting is given when the operation is performed under reasonable and theoretical control, and high grade castings are obtained with a high degree of certainty. It is possible to continue the melting operation without repairs and patching. Thus low cost and more efficient operation verified the economic advantages of water cooled cupola.

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