The authors investigated the influence of solute contents (Cu or Si content in Al binary alloys) on the heat transfer coefficients on the interface of casting-mold, which is evaluated from the heat flux through the casting-mold interface on solidification.
  After the heat transfer coefficient reached a maximum value, the heat flow through the casting-mold interface for the mushy zone type alloy fell largely with time after pouring. But for the skin formation type alloy, the maximum value and the reduction of the heat transfer coefficient were smaller than those of the mushy zone type alloy. After the heat transfer coefficient reached a maximum value, the temperature at the casting-mold interface in the mold decreased temporarily in the mushy zone type alloy. In the initial stage after pouring, the heat resistance in casting-mold of the mushy zone type alloy was smaller compared with the skin formation type alloy. After this stage, the air gap thickness was larger. The average heat transfer coefficient in the casting-mold interface increased with the increase in solute content of Al-Cu and Al-Si alloys up to the solubility limit.

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  The instrumented Charpy impact test and microfractography were carried out on an annealed nodular cast iron with ferritlc structure and fracture characteristics of Charpy specimens with various types of notches were examined.
  The maximum plastic stress concentration factor K?? was calculated by applying the slipline field theory and linear elastic fracture mechanics. From this, K?? was appreciated to be 1.47 for the specimen with U notch and 2.06 for the specimen with V notch. When total energy required to fracture the specimens are divided into two parts, i.e. crack initiation energy and crack growth energy (propagation energy) at the maximum load, it is estimated that unnotched specimens show mainly a transitional behaviour of crack-initiation energy, the specimens with U notch both initiation and propagation energies, and the specimens with V notch mainly propagation energy.

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  The displacement of the punch used for application of load on castings in squeeze casting is as much as the change in the amount of volume with the progress of solidification. This displacement causes reduction of effective pressure of liquid phase, friction at casting-mold interface and so on. The measurement of the displacement was carried out with cylindrical and rectangular pure aluminum castings. The correlation between the displacement of the punch and reduction of effective pressure was also discussed.

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  The paper describes the mechanism of formation and method of prevention of cold shut in high strength steel castings and its influence on the fatigue strength.
  The microscopic observation showed that there was an oxide film layer under the concavity of cold shut which was formed by collision of molten metal. On the other hand, according to casting experiments the effective factors on the prevention of cold shut were 1) less amount of addition of oxidizing elements such as manganese and titanium; 2) less gates or inclination of the mold in order to reduce collision of molten metal; and 3) the device to run molten metal with minimum temperature drop-inclining and washing the mold.
  Judging from the above, the concavity of cold shut was formed after the capacity to recover was lost by the large apparent surface tension at the site where molten metal covered with oxide film or solidification film collided. Authors also found silica mold wash the most practical for cold shut prevention and economical because partial mold wash can be done at the needed region. The torsion fatigue test of hollow thin section castings showed that other casting defects such as blow holes and scabs were dominant factors of fracture, and the pure influence of cold shut on the fatigue could not be found in this experiment.

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  Despite the many investigations on the effects of various elements on the formation of spheroidal graphite in cast iron there are only a few studies that report on how these elements harmfuly influence the formation of spheroidal graphite. In order to clarify this problem, experiments were conducted to study the inhibitory effects of tellurium and selenium on the formation of spheroidal graphite.
  The base metal composed of electrolytic iron and electrode graphite was melted in a high frequency induction furnace and cast into an iron mold. In a fused silica crucible 50 grams of this alloy with a carbon content of 4.35% was placed and melted in a resistance furnace, and then tellurium and selenium up to 1.0% were added to the melt. At 1,350°C the melt was treated with Fe-Si-Mg(21.4%) alloy and cooled while the cooling curve was plotted. On these furnace-cooled specimens, the graphite structure was observed and the spheroidization degree of graphite was measured. Also, X-ray diffraction analysis was carried out on the powder which was produced by the magnesium-treatment in a fused silica crucible.
  By increasing the addition of tellurium or selenium, residual magnesium content decreased and the shape of graphite changed successively from spheroidal to vermicular, undercooled and flaky. MgO, MgS and MgSe were determined in the reaction product of the magnesium-treated iron melt containing O, S and Se, respectively. However, MgTe could not determined in the Tecontaining iron because of lack of standard diffraction data. Tellurium and selenium consumed the residual magnesium which was necessary to form the spheroidal graphite just as the inhibitory manner of sulfur and oxygen. According to the previously reported classification of the inhibitory behaviour of the elements in the spheroidization of graphite, i.e. the classification into sulfur type, titanium type and lead type, these two elements were classified into the sulfur type (Mg-consuming type).

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  In vacuum molding process, the plastic film covering the surface of the mold peels sometime during pouring. This causes defects in the casting. It was thought that factors affecting stripping off the film were the force of heat contraction of the film, the elastic force of contraction retained in the film after formation and the vacuum force on the mold.
  The main factor causing stripping of the film was the elastic force of contraction that arised on forming and retained in the film. The force of heat contraction of the film little affected the stripping of the film, and just after the film strip, caused it to rapidly contract. When pressure in the mold was higher, the film stripping tendency became greater. The pressure in the mold increased during pouring, however, the pressure difference between the mold and the mold cavity was maintained when the film was not stripped, and it was not kept when the film was stripped.

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  Matrix grain refinement of spheroidal graphite cast iron by means of two thermal techniques was studied. The specimens used for the investigation were normalized at 880°C for 1hr., so that they had structures consisting of lamellar pearlite. The first technique involved repetitive austenitizing at relatively low temperatures in the austenite range and air cooling. This technique allowed spheroidization of pearlite. In the second technique, after rapid heating to the upper region of eutectoid transformation temperature range, specimens were air-cooled. In this case, a fine grained matrix structure was obtained which was 5-6μ in size and consisted of grains of ferrite and pearlite.
  The region of eutectic cell boundaries had a tendency to remain a coarse pearlite structure because of concentration of manganese and depletion of silicon. Accordingly, grain refinement throughout the matrix in cast iron required that the transformation temperature was much the same throughout the matrix. In order to do this, iron with very low manganese content and almost no trace elements had to be annealed for a long time at high temperatures for homogenization.

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