With a view of investigating the details of the hardenability of low sulphur pearlitic malleable iron desulphurized with calcium carbide, the hardenability of two series and eighteen levels of pearlitic malleable irons were studied by the end-quench test cooled with both oil and forced air blasting. The first series was a low sulphur pearlitic malleable iron containing various amount of manganese in excess of that required to balance the sulphur and the second was pearlitic malleable iron having various manganese to sulphur ratio but with the amount of manganese always in excess of the content enough to balance with sulphur. The amount of excess manganese selected for these materials were between 0.02 to 0.94%. However, the range of the manganese to sulphur ratio was distributed from 1.6 to 68.6.
  The hardness at 3mm depth from the quenched end of specimen increased with the amount of excess manganese. The oil quenched iron showed greater increase in hardness than that of the air quenched material. The distance from quenched end showing H_RC40 in oil quenched and H_RC34 in air quenched specimen also increased with the excess manganese content. The amount of excess manganese had the effect of both improving the hardenability of the iron as well as retarding the spheroidization of cementite during tempering. Low sulphur pearlitic malleable iron having 0.010 to 0.020% sulphur fad same hardenability as that of the alloy peariitic malleable iron having 0.6 to 0.7% manganese in excess of that required to balance the sulphur.
  The amount of manganese sulphide inclusion decreased with sulphur content. The relationship between these two factors could be shown by the formula; y=4.05x+0.01, where y is number of MnS and x is S%.
  No distinct correlation was observed between graphite nodule number and the amount of excess manganese in the specimen which were added with manganese and/or sulphur. However, graphite nodule number increased proportionally with the increase in the manganese to sulphur ratio. On the other hand, the desulphurized specimen showed no distinct correlation between graphite nodule number and the manganese to sulphur ratio. Also, this specimen had greater graphite nodule number than the specimen which were added with manganese and/or sulphur.

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  While there are crucible furnace, rotary furnace and induction furnace for melting pure copper, gas content in molten pure copper depend upon the atmosphere in the furnace. In the present work, hydrogen and oxygen content in pure copper molten in various type of melting furnace as well as the influence of the furnace atmosphere on the soundness of pure copper castings were investigated.
  Oxygen content of pure copper melted in butane-fired crucible furnace remained stable, but it was variable in the butane-fired rotary furnace. Both oxygen and hydrogen content in molten copper was extremely low in vacuum compared to in ordinary low frequency induction furnace. The density of the pbosphorus-deoxized copper castings made by the melt from butane-fired crucible furnace was very low. For the induction furnace, the density of phosphorus-deoxidized copper castings proved to be sound with a range of 8.88 to 8.90 g/cm³.

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  The remarkable growth of cast iron observed in air and in carbon monoxide has been attributed to oxidizing and to carburizing, respectively. However, their precise mechanisms have not been elucidated to date. In the present work the growth of flaky and nodular graphite iron were examined in carbon monoxide atmosphere and the results were analyzed theoretically based on the growth mechanism of irreversible graphite migration proposed by the author.
  Growth of flaky graphite iron in carbon monoxide was much greater than that in vacuum. There were more growth with temperature difference of cyclic heating in the austenite region. The maximum growth was observed by a heating cycle of 950-800°C. Irreversible dimentional increase of the iron was also observed while heating at 950°C. Flaky iron which grew in CO atmosphere showed structural change due to carburization and formed black network with pearlitic matrix. Influence of CO atmosphere on the growth of spheroidal graphite cast iron was minor, but some increase in growth and structural change due to carburization were observed when the heating cycle was 950°C-800°C.
  Carburization in CO accelerated the growth of cast iron during cyclic heating in the austenite region. The mechanism can be interpreted as a repetition of two processes of dissolving of carbon by carburization and the separation of graphite in the matrix, ultimately resulting in the volume increase. Because cyclic heating and cooling in the austenite region can assist the process of carburization, the growth of iron was promoted remarkably in CO atmosphere. The black network around graphite flake was analyzed as carbon and silicon oxide by X-ray microanalysis. The result formed showed that there is a penetration of ambient gases via the graphite flakes and also the presence of an apparent oxidizing effect inside the cast iron that has marked growth.

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  A trial device for measuring gas pressure in molds and cores at casting was designed and its feasibility was studied in shell mold casting. The device mainly consisted of a thin gauge steel tube, one end for embedding in motds for the introduction of pressured gas and the other end mounted with a gas pressure gauge made of a silicon diaphragm. Gas pressure in cores were measured by the use of semiconductor pressure transducers, while iron was cast at 1,400°C. The cores used were shell mold cores 100 mm wide, each with a core print for degassing on its open side, and were varied in the following factores : length and thickness of core, resin content and grain size of sand.
  Hydrostatic pressure measurement conducted for the purpose of calibration, showed that the output electrical signal and the pressure were in linear relationship in the range of 0-0.3 kg/cm². The maximum gas pressure in an unvented shell mold core wholly surrounded with molten cast iron was found to be equal to hydrostatic pressure of the molten cast iron at the top of the core. When gas pressure at the core surface exceeded the hydrostatic pressure of the molten metal, gas blew out into the molten metal and formed gas bubbles.
  The gas pressure distribution was not uniform in the core. The pressure increased with the distance from the core print. For cores with the same thickness, the gas pressure increased with the core length. The gas pressure at the tip of the 200 mm core did not agree with but was higher than the estimation obtained by extrapolation of the gas pressure curve plotted with the 100 mm and 150 mm cores. Even at the same distance from the core print, the gas pressure in the longer core was found to be higher. For the cores with the same length, the gas pressure increased with the decrease in the core thickness. For the core made ot sand with AFS grain size number 29.2, the gas pressure increased with resin content, while for the core made of sand with AFS number 52.7, the gas pressure showed only a slight increase irrespective of the increase in resin content. When the structural configuration and the resin content were kept constant, the gas pressure increased with the decrease in the grain size of the sand used, and the gas pressure increase was inversely proportionai to the permeability of the core.
  This device has thus been proved to facilitate measurement of gas pressure at various parts of the core, even those with a complicated configuration, and the resulting gas pressure-time curve is greatly effective in preventing the casting defects attributed to gas bubbling.

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  Dry wear tests were carried out for flaky and spheroidal graphite cast irons which were designed to have ferrite matrix in order to attain grain refinement as well as to cancel the matrix effect. The wear mechanism was studied through measurements of effective strain and particle size in the sliding surfaces of the cast irons by means of X-ray diffraction.
  It was shown that the effective strain and particle size in the sliding surface depend on the shapes of graphite in the cast irons and that the strain in spheroidal graphite cast iron was larger than that in flaky graphite cast iron and was anisotropic. It was suggested that superior wear resistance of spheroidal graphite cast iron may be explained in terms of the graphite shape effect on stress concentration characteristics.

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  Drawing-up continpous casting was applied for the Al-Si alloys containing 9, 11.7 and 13%Si. The molten metal was introduced into water-cooled copper mold of 54mm diameter and 60mm length through a syphon gate. The solidified shell in the mold was drawn-up continuously and/or intermittently. Surface appearances and microstructures of the drawn-up pipes were examined. The pipe thickness were measured as a function of the drawing rate and compared with those calculated by the finite difference mehtod.
  It was difficult to draw up Al-9%Si and 13%Si alloy pipes. Al-11.7%Si alloy pipes could be drawn-up continuously as well as intermittently. The maximum drawing rate was about 110cm/min. The thickness of Al-11.7%Si anoy pipes were about 1.5-4mm. It was considerably thinner than those of pure Al and Al-Cu alloy at the same drawing rate. That may be caused by the larger latent heat of fusion and the larger air gap between the pipe and the mold that result from the greater strength of shell at high temperature.
  Defects observed on the outer surface of pipes were transverse wrinkles and dimples. That may be influenced by the conditions of the joint between the mold and the runner. On the inner surface, there were small protuberances like sand particles and relatively large swells that corresponded to the outer defects. These small protuberances were part of the α-dendrites.

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  When calculating the solidification rate or solidification time, which is the most important factor in controlling the quality of castings and ingots, it is necessary to know the metal-mold heat transfer coefficient. The heat transfer coefficient was determined in relation to the kinds of metals and mold materials, the difference of the contact clearance between metal and mold, and the relative volume of mold and casting.
  The heat transfer coefficient was nearly constant for the kinds of melts (pure Al, pure Cu and pure Fe) and mold materials (pure Cu and cast iron) without dressings. The values obtained in this work were 0.18cal/cm²·sec·deg for pure Al melt, 0.19cal/cm²·sec·deg for pure Cu melt and 0.14cal/cm²·sec·deg for pure Fe melt. For the electrode graphite mold, however, the values of the heat transfer coefficient fluctuated very much depending on the sample. The heat transfer coefficients varied with the difference in the contact clearance. The heat transfer coefficient in the direction perpendicular to the gravity was 61% of that in the direction parallel to the gravity. The increase in the heat capacity of the mold increased the heat transfer coefficicient and decreased the solidification time.

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