关键词: 水玻璃砂；粉末硬化；常温强度；残留强度；抗湿性

Abstract:

The performance characteristics of sodium silicate sand hardened by superfines were studied, and it was compared with the performance of sodium silicate sand hardened by ester, which was adopted widely in the foundry enterprises at present. The microstructure of sand samples hardened by ultrafines or ester, including the sand samples at room temperature and roasted at 800℃,was observed by SEM.The results show that the room temperature strength of the sand samples hardened by ultrafines is increased about 23% and the residual strength is reduced about 76% to the sand samples hardened by ester.In the ultrafines hardening process, the added quantity of sodium silicate is 3% and the added quantity of ultrafines is 25% of the added quantity of sodium silicate. The sodium silicate sand hardened by ultrafines is not sensitive to the module of the sodium silicate. In the hardening process, using high module sodium silicate can
improve significantly the collapsibility and reclamation performance of the sand. The moisture resistance of the sodium silicate sand hardened by ultrafines is better than that of the sodium silicate sand hardened by ester.

Key words: sodium silicate sand, hardened by superfines, room temperature strength, residual strength, moisture resistance