The first stage graphitization time of white cast iron varies with the holding temperature. The difference of the holding temperature signifies the difference in the ratio of cementite and austenite in the white iron at the temperature before annealing. Therefore, the different ratio suggests the transformation of the rate controlling step in the graphitization reaction. This step, which may be solution of cementite or diffusion of carbon, iron or silicon, is thought to affect the formation of the temper carbon. The authors have already suggested a new classification of five types of temper carbon, which are spheroidal, compact, aggregated, snow-flaky and fine by controlled solidification and graphitization of pure white cast iron. The present investigation is conducted to find the precipitation condition of various types of temper carbon with the different annealing cycle of graphitization. The concept of “the stability of an austenite shell”, which means that austenite affects the growth of graphite nucleus, is introduced to explain the various types of temper carbon and the rate controlling step of graphitization reaction.

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  The primary moisture content of fluid self-hardening mixture is higher than that of self-hardening sand or CO₂ sand. It is said that the mold made of fluid self-hardening mixture contains a large number of bubbles by which permeability is high in spite of high humidity. Therefore, the mold is used without drying. However, our experience shows that pouring defects due to the mold moisture often appears. This report is a study on the behaviour of mold moisture and method of prevention of pouring defects for fluid self-hardening mold. The results obtained were summarized as follows;
 1) When the fluid self-harding mold was left indoors, only the moisture contained in the surface layer was eliminated.
 2) The compressive strength and permeability increased rapidly as moisture in mold was eliminated.
 3) Pouring to the frozen metal within 24 hours of molding may cause deformation of the setting core by the pressure of the molten metal or scab formation, therefore, it is desirable that pouring is conducted after leaving the mold for 24 hours.

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  Continuous casting process has been widely used for production of billets but not as much for the production of pipes. We have made a trial equipment similar to that reported by A.I. Veinik to produce pipes directly from molten metal. The main advantage of this method is the absence of the inner core used in conventional machines for continuous casting of pipes. In this paper, the details of our drawing-up experimental equipment and the results of the experiment using commercial pure aluminum are reported. The pipes were drawn upward intermittently through the water-cooled copper mold of 54mm inner diameter and 60mm length. Their thickness varied from 13mm to 4mm according to the rate of drawing of the pipe, 15-60 cm/min. Small circular protrusions at regular intervals were formed on the internal surface. Hair cracks and dirty parts were often found on the external surface. The conclusions obtained from our experiments are as follows:
 1) Pipes can be produced by the drawing-up method.
 2) Small circular protrusions can be reduced by controling the drawing length or the surface level of the molten metal.
 3) The inner surface of these pipes are better than that of the pipes produced by the conventional method.
 4) As the solidification at the junction of the mold and the runner affects the soundness of the external surface, the equipment should be designed so that rapid solidification will take place only within the mold.
 5) In this study, the apparent heat transfer coefficient between the mold and the pipe varied from 200 Kcal/m²hr°C to 2,800 Kcal/m²hr°C with the rate of drawing.

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  It is well known that some degree of difference in tension-test results is between the test pieces taken from Y-block and the actual body of Cast steel. The purpose of this study is to clear the item which shows the most remarkable difference, the degree of difference and factors causing the difference. Therefore, the following experimental method was employed for this study : Strength measured at the tension-test for Y-block and test pieces from the SC-49 Axle-Box (Fig. 1), Disk-Brake body (Fig. 3-cast in graphite mold), the 18-8 stainless steel casting Valve-Yoke (Fig. 5-6) and the 1.5Cr-0.5Mo Shaft body (Fig. 7) was compared, after which the same tension-test was made on the test pieces in Fig. 8 to confirm the above test results.
  The results show the following:
  The tension-test value on the actual body is lower than that on Y-black (see Table 2-8). The strength of the former is about 80-90% of the latter and the elongation of the former is about 60-90% of the latter. As these differences were already recognized at the as-cast condition, it is considered that caused factors for the difference may be the feeding-effect and the cooling condition during the solidification process.

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  In order to analyze the solidification process with vibration, a simplified heat transfer system was constructed : an air cooled cylinder with spherical head, called Libuid Surface Contactor (LSC), extracts the heat in molten aluminum from its surface and sets up a temerature field of approximately steady conduction in the metal. Vertical vibration of 0.7 mm at 17Hz is applied only to LSC.
  The theoretical analysis has been carried out assuming the system to be of a unidirectional and steady conductive heat transferer. A dimensionless temperature of the liquid, η, that is the ratio of superheat temperature of the liquid at infinite distance to the rate of heat extraction, has an important role in this solidification process. According to η, the process is divided into three steps; (a) (η>1), no solid in the metal, (b) (1>η>0), a grown solid on LSC and liquid in the other metal region, (c) (1>η>0), with vibration all the solids deform into particles which transfer and remelt in the liquid, namely, a step of a solid-liquid mixture region and a liquid region.
  The temperature fields of the metal region have been theoretically calculated for every step. Some theoretidal results should be emphasized : the temperature of the mixture region is almost the same as the melting point of the metal, the remelting of the solid particles occurs at the end of the mixture region, and that the radius of the mixture region increases in invers proportion to η.
  In LSC experiments, the measured factors are the rate of heat extraction, the temperature of several points in the metal, and the macrostructure of the resulting ingot. The behavior of these factors in the experiments in which the period of vibration and flow rate of cooling air are changed as variables agree well with the theoretical results. It is concluded that the vibration together with the forces transfering the solid particles makes the solid-liquid mixture region in the metal and that the fine equiaxed structure of ingot forms after the mixture region prevails over the metal region.

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