The effect of adding SBR latex to backup slurries on the properties of ceramic molds in investment casting

[1]        S. Jones, M. Jolly, and K. Lewis, "Development of techniques for predicting ceramic shell properties for investment casting," British ceramic transactions, vol. 101, no. 3, pp. 106-113, 2002. [2]        S. Pattnaik and M. K. Sutar, "Effect of saw dust content on slurry rheology and mechanical properties of the investment casting ceramic shell," International Journal of Metalcasting, vol. 15, no. 2, pp. 470-487, 2021. [3]        Y. Venkat, N. Hazari, M. Baig, S. Singh, and N. Das, "Mullite shell mould for casting of advanced CG and SX components in nickel based superalloys," International Journal of Cast Metals Research, vol. 26, no. 2, pp. 114-122, 2013. [4]        C. Mahimkar, "Thermo-physical properties measurement and steel-ceramic shell interactions in investment casting," 2011. [5]        S. Pattnaik, "An investigation on enhancing ceramic shell properties using naturally available additives," The International Journal of Advanced Manufacturing Technology, vol. 91, no. 9, pp. 3061-3078, 2017. [6]        S. Jones, "Improved sol based ceramic moulds for use in investment casting," University of Birmingham, 1993. [7]        P. Huang, G. Lu, Q. Yan, and P. Mao, "Effect of ceramic and nylon fiber content on composite silica sol slurry properties and bending strength of investment casting shell," Materials, vol. 12, no. 17, p. 2788, 2019. [8]        H. Wu, D. Li, and N. Guo, "Fabrication of integral ceramic mold for investment casting of hollow turbine blade based on stereolithography," Rapid Prototyping Journal, 2009. [9]        C. Konrad, M. Brunner, K. Kyrgyzbaev, R. Völkl, and U. Glatzel, "Determination of heat transfer coefficient and ceramic mold material parameters for alloy IN738LC investment castings," Journal of Materials Processing Technology, vol. 211, no. 2, pp. 181-186, 2011. [10]      Y. Venkat, K. Choudary, D. Das, A. Pandey, and S. Singh, "Ceramic shell moulds for investment casting of low-pressure turbine rotor blisk," Ceramics International, vol. 47, no. 4, pp. 5663-5670, 2021. [11]      A. C. Reddy and S. S. Rajan, "Analysis of hot ceramic shell behavior at casting conditions," in National Conference on Investment Casting, Hyderabad, 2006, pp. 138-142. The effect of adding SBR latex to backup slurries on the properties of ceramic molds in investment casting Elahe Ayoubi *, Amir Mahdi Shabani, Monireh Rzazan, Ali Makhdoumi, Salah Isafi , Javad Damghani                                                                pars investment casting company, Shahrood, Iran (*[email protected]) Abstract Investment casting is an effective way to produce very thin and most complex components with very high-dimensional accuracy and surface finish. One of the steps in the production of components by investment casting is the production of ceramic molds, which are often made of colloidal silica adhesive due to the strength of the molds fired molds. However, this type of adhesive has low strength in green molds, which sometimes causes the molds to fail; hence additives such as fiber or polymer are used to avoid mold failure. Turbine blades are also produced by investment casting due to their sensitivity and high dimensional accuracy. The present study aims to achieve the desired properties in ceramic molds by adding SBR latex to the slurry. For this purpose, layers of slurry with the following two compositions are applied to the wax patterns: a) refractory powder and colloidal silica, b) refractory powder, colloidal silica and latex SBR. Based on this, two ceramic molds from the blade model were layered with the two mentioned compositions and different thicknesses. According to the results, the addition of SBR latex increased Sag Resistance and flexural strength of the molds in the green state and at high temperatures. Examination of the 3D scan results showed that the dimensional accuracy of the cast blades improved at 1400 ° C.