MIXTURE FOR PREPARATION OF GYPSUM MOLDS AND CORES IN PRODUCTION OF CASTINGS FROM NONFERROUS AND PRECIOUS ALLOYS AND METHOD OF MIXTURE PREPARATION

摘要

foundry. SUBSTANCE: mixture contains, wt.%: gypsum, 10-14; dinas powder, 15-26; dusty sublimate of fireclay production, 3-7; dusty quarts, 25-40; aluminochromophosphate binder, 0.05-0.12; surfactant, 0.007-0.015; water, the balance. Dusty quartz compensates expansion of dinas powder in heating. Preparation of mixture includes preliminarily preparation of gypsum-air mixture and its treatment with electrical field with intensity of 500-1000 V/m. EFFECT: increased mechanical and physical properties of molds and cores, improved quality of art castings, especially, massive and large-size ones. 3 cl, 3 tbl, 2 ex