| 摘要 |
A thermoplastic paste for the production of foundry mold cores comprises, per 100 parts by weight of mineral filler comprised of fused silica, zircon and cristobalite, between 0.2 and 0.5 parts by weight of a mold release agent, and an organic binder formed by at least 15 to 20 parts by weight of polyethylene glycol having an average molecular weight between 1400 and 1600. A process suitable for the production of foundry mold cores from such a past comprises a shaping stage followed by a single firing cycle in four steps, namely, (a) raising the temperature to 500 DEG C., at a rate of between 30 DEG C. and 50 DEG C. per hour. (b) raising the temperature from 500 DEG C. to a maximum temperature, at a rate of between 100 DEG C. and 200 DEG C. per hour. (c) maintaining the said maximum temperature for a period of between 4 and 5 hours, and (d) cooling rapidly using pulsed air.
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