厚壁细孔铸铁件消失模水基涂料的研究与应用

针对厚壁细孔铸铁件在消失模铸造条件下的凝固特点，选用铬铁矿粉、石灰石粉及石墨粉作为耐火骨料，钠基膨润土、羧甲基纤维素钠（CMC）和黄原胶为复合悬浮剂，聚醋酸乙烯乳液（自乳胶）和磷酸盐为复合粘结剂配制厚壁细孔铸铁件用消失模水基涂料。通过正交试验，确定了涂料的最佳配比，即耐火骨料由70％的铬铁矿粉、15％的石灰石粉和15％的石墨粉组成，钠基膨润土、CMC、黄原胶、白乳胶、磷酸盐与耐火骨料的质量比，分别为5．0％、0。5％、0．1％、0．5％和2．0％．试验和生产应用结果表明：该涂料具有优良的悬浮性、涂层强度、透气性和高温抗裂性等性能，能有效地防止铸件粘砂缺陷的产生。

Study and Application of Water-base Coating to Iron Castings with Thick Wall and Small Holes in EPC

A water-base coating for iron castings with thick wall and small holes in EPC was prepared by using chromite, limestone and graphite powders as the refractory material. Na-bentonite, CMC and xanthan gum were taken as complex suspending agent, and polyvinyl acetate emulsion and phosphate were taken as a complex bonding agent according to the characteristics of solidification process of iron castings with thick wall under EPC. The optimum ingredient ratio of the coating was determined by orthogonal experiment. Namely, the refractory material was composed of 70% chromite powders, 15% limestome and 15% graphite however, CMC and xanthan gum, polyvinylacetate emulsion and phosphate, respectivelly being 5.0%, 0.5%, 0.10%, 0.5%, and 2.0%. The experiment and application results show that this coating has good suspension property, layer strength and high temperature crack resistance, and can avoid sand adhering to casting parts effectively.