| 摘要 |
investment casting of jewelry from alloys of precious and nonferrous metals. SUBSTANCE: powder mixture from preparation of mold mixed with water in molding contains, wt.%: cristobalite, 48-78; high-strength gypsum (alpha+beta), 20-50; potassium nitrate, 0.5-2.0; potassium dihydrophosphate, the balance. Cristobalite is used with admixture of tridymite and amorphous quartz in amount of not more 20 or 40%, and alkali metal oxides, not more 2.0%. EFFECT: higher strength characteristics of molding sand ensuring high quality of castings. 3 cl, 6 tbl |
