Usenko R. Scientific and technological principles of ceramic shell making with the use of import substituting and industrial raw materials for investment casting

In the present work modern manufacturing procedures for production of general engineering grade castings have been reviewed. Main features of the used manufacturing processes; refractory and binding materials were highlighted. Influence of the ceramic shell properties and the production process on the shell thermal shock resistance indicator. Kinetics of the ceramic shell linear dimensions change has been studied, both during dewaxing and firing steps. Gas emissivity, ultimate static bending strength and linear expansion factor for the ceramic shell have been defined as a function of the slurry and stucco material properties, as well as shell drying time and tem-perature. Principles of defect formation in the shell originating from gas and foreign particle entrapment have been described. The pattern-making die cavity design equation has been specified with more degree of accuracy with the die cavity design coefficients defined. Based on the results of studying the physical and chemical properties as well as processing characteristics of the materials used in making the multilayer ceramic shells a production process has been developed for making investment casting ash-and-quartz ceramic shells.