消失模壳型铸造的高强型壳研究

Study on High-Strength Ceramic Shell of Expendable Pattern Casting

型壳制备是消失模壳型铸造的关键技术之一。针对硅溶胶型壳干燥慢、湿强度低的问题,试验研究了添加有机低温粘结剂后的型壳性能。试验结果表明:撒砂材料添加有机粘结剂粉末能够提高型壳的湿强度,其中聚乙烯醇(PVA)的提高幅度最大,达到20%,然后依次为糊精、羧甲基纤维素钠(CMC)、α淀粉,提高幅度分别达到11.3%、9.4%、5.0%。

Production of ceramic shells is a crucial part of the ceramic shell expendable pattern casting（EPC）process.Considering the long drying time and low wet-strength of ceramic shells produced with silica sol,the commonly used organic binders were added into silica sol,slurries or refractory stucco and the properties of the shell were investigated.The results show that adding of organic binder into refractory stucco can increase the wet-strength of shells.Among the investigated binders,PVA has the biggest influence on wet-strength,which is rised by 20%,and for dextrin,CMC and α-starch are rised by 11.3%,9.4% and 5.0%,respectively.