The sand erosion resistance and corrosion resistance of 15%Cr-1%Si-1%Ni-3%Mo-2%Cu-1%W-1%V white cast irons were studied by measuring the weight loss in a stiring flow system and measurement of anodic polarization curves.
  The addition of B up to 2% to the base alloys improve the sand erosion resistance and corrosion resistance in the as cast and heat treated alloys (930°C×3hr, followed by air cooling). The corrosion resistance of as cast alloys are better than that of heat treated alloys.
  Through these experiment it was concluded sand erosion resistance were controlled by corrosion resistance.

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  The effect of the forging ratio on the static strength and impact properties was investigated in a ferritized spheroidal graphite cast iron. Graphite spheres are changed into disk shapes by forging. The tension and impact tests were performed on two kinds of specimens, graphite disks are parallel and vertical to the direction of applied tensile stress. These are termed here as parallel and vertical specimens, respectively. The tensile strength of the parallel specimens hardly changes up to 60% of the forging ratio, while that of the vertical specimens decreases monotonously with increasing the forging ratio. The elongation decreases with increasing the forging ratio in both parallel and vertical specimens. The upper shelf energy, though depending on the kind of specimens, decreases with increasing the forging ratio. The energy transition temperature of the vertical specimens is not changed by forging, while that of the parallel specimens shifts to the lower temperature with increasing the forging ratio.

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  The influence of chemical composition with Cr/C ratio of 2∼10 and destabilization heat treatment on transformation characteristics of high chromium cast irons was investigated with dilatometer. Two series of compositions are used : a) in variation of Cr/C ratio from 2 to 10 with keeping constant of another alloying elements, b) 3%C-20%Cr and 3%C-7%Cr alloys with 1.5∼5%Ni, 1∼5%Mo and 0.5∼2.5%Si.
  Transformation behaviors of high chromium cast irons are affected by the chemical composition, destabilization temperature and cooling rate. Martensite transformation temperature (M_S) rises both with lowering cooling rate and with increasing destabilization temperature for any composition. M_S remains almost unchanged and does not depend on the destabilization temperature, however, when cooling rate is slower than 1°C/min.
  M_S rises with increase of Cr/C ratio for a given destabilzation temperature and cooling rate. Banitic transformation occurs for Cr/C ratio smaller than 5 when cooling rate is lower than 4°C/min. Conversely, there are only martensitic transformations for Cr/C ratio larger than 5. Microscopic examination can hardly distinguish martensite from bainitic structure, however, the hardness decrease largely with presence of banitic structure.
  In additon to be affected by Cr/C ratio, M_S temperature increases with increase of Si content and decreases with increase of Ni content. The effect of Mo content is little on M_S temperature.

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  The primary morphology and mechanical properties of hypoeutectic gray cast irons with low carbon content and carbon equivalent (CE) stirred mechanically on the primary solidification process by rotating a propellor inserted in the melt were investigated, and considerations were made on the effects of the primary morphology on the strength of gray cast irons based on the observations of the fractured process of specimens. The primary austenite morphology is refined and distributed uniform by stirring at this experimental condition. The refined primary grains contact and connect each other with their growth on the solidification process after the stirring, and finally becomes the continuous and complex morphology. With increasing the stirring speed, the tensile strength of gray cast irons increases and the degree of increase in tensile strength is higher in the lower CE cast irons. When the specimen with the primary morphology refined and continued by stirring is fractured, it is more frequent that the cracks propagate through the primary parts. The tensile strength increases in proportion to the ratio of the primary parts occupied in the fractured path of cracks.

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  Effect of magnesium contents alloyed in the spheroidizing additives on chilling tendency of spheroidal graphite cast iron were studied with the metal molds of 20, 25 and 30mm in diameter. Chilling tendency was moderated when magnesium contents alloyed in additives was reduced with reducing the treatment temperature from 1500°C to 1400°C. However, in the case of the additives of less than 5% Mg, chilling tendency treated at 1350°C was greater than treated at 1400°C.
  The chilling tendency increased with increasing magnesium vapour pressure calculated with equation of P. K. Trojan, and remarkable chill formation occurred in case of 1500°C treatment with Mg vapour pressure of more than 2 atm. The least chilling tendency was, on the other hand, observed at 1400°C treatment with Mg vapour pressure of 0.3-0.5 atm.

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  This paper is concerned with the production condition to obtain the 10mm diameter Al-4.5%Cu alloy rods by the conventional continuous casting machine whose graphite mold length is kept constant in the range from 100mm to 140mm.
  The secondary dendrite arm spacing in rods decreases with increase of casting speed. The position of liquid-solid interface in mold depends on casting speed. The larger G/R-value (G : temperature gradient, R : casting speed) leads to the unidirectional solidification of thus produced rod.

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  The flow and temperature change behaviors of molten aluminum flowing through a thin cavity, as in intake manifold castings, were investigated.
  Molten metal flows through a thin cavity at a constant rate in the liquid state. However molten metal is cooled to the solidifying temperature, the flow rate rapidly decreases till the flow stops. The molten metal temperature decreases at a constant cooling rate in proportion to the flowing time, regardless of the casting temperature and the flow rate. The cooling rate of molten metal is determind by the thickness of the mold cavity. For a shell mold with the cavity thickness of 8 to 3mm, the cooling rate varied from 40 to 160°C/s. For a intake manifold castings made with a die and a shell mold core, it was 40 to 50°C/s. However, the molten metal temperature hardly decreases after solidification is started due to the radiation of latent heat.

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