| The matrix structure and the morphology of CV graphite are affected by the addition of various kinds of elements, which are contained in the CV graphite cant iron, additives, fading time and cooling rate. The effects of cooling rate on the matrix structure, the shape of CV graphite, mechanical properties and propagation of ultrasonic wave in hypereutectic CV graphite cast iron were studied. When the diameters of the specimens were reduced from 50 ㎜ down to 20 ㎜, the following results were obtained : 1) CV graphite count showed 10.4 % increase and CV graphite length showed 17.3 % decrease. 2) The content of graphite and ferrite showed 10.8 %, 3.7 % decrease and that of pearlite showed 36.2 % increase. 3) Hardness and tensile strength showed 3.1 %, 10.3 % increase and impact strength showed 1.5 % decrease. 4) Ultrasonic wave velocity showed 1.1 % increase. |
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