| 摘要 |
PURPOSE:To easily dispose an alloy element into a casting mold in a short period and to obtain a good casting by preliminarily attaching a metal to the special casting mold and fitting the same to the casting mold in the case of producing the casting part only for the part of which special properties are required. CONSTITUTION:The ball joint part of a steering knuckle which is the casting part for a front drive passenger car is required to have wear resistance and resistance to permanent set in fatigue and the other parts are required to have impact resistance. A CO2 mold preliminarily attached with Sn is fitted to a cope in the same manner as for housing a core by which the Sn is disposed to the ball joint part. The soft ferrite base in the whole part and the hard pearlite base in the local part are thereby obtd.
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