我厂生产高、中压阀门铸钢件,型砂、芯砂多年来一直采用水玻璃作粘结剂的七○砂,CO_2硬化,进烘炉烘烤后再合箱浇注。用水玻璃砂毛病不少,特别是芯砂,突出的问题是溃散性差、清理困难;铸件表面质量不好,影响外观且加工时刀具磨损消耗大。我们采用聚乙稀醇(17-88)(简称P.V.A)做芯砂粘结剂,解决了上述长期存在的问题。 P.V.A(17-88)是一种高分子化合物,白色颗粒能溶于水,通常需加热水溶液促进其溶解,溶液的粘结力随浓度增加而增强。一般 I plant the production of high and medium pressure valve steel casting, sand, sand core water glass has been used for many years as a binder seven sand, CO_2 harden, into the oven and then combined with a box of baking. Many problems with water glass sand, especially the core sand, the outstanding problem is the collapse of poor, cleaning difficulties; casting surface quality is poor, affecting the appearance and processing tool wear and tear consumption. We use polyvinyl alcohol (17-88) (P.V.A) as a core sand binder to solve the long-standing problems. P.V.A (17-88) is a polymer compound, white particles can dissolve in water, usually heated aqueous solution to promote its dissolution, the solution of the adhesive force increases with increasing concentration. general