Abstract
The focus of the authors is on the production of high-quality thin-walled steel castings obtained by special methods of precision casting. One of the main reasons for the poor quality of steel thin-walled castings and, as a result, the formation of such defects as burn-in, rough surface, roughness, finesse and underfilling, is the imperfection of the casting mold. In addition, the specific problems of thin-walled steel casting are associated with an insufficient level of fluidity of the alloy in the range of working temperatures of casting, as well as the emerging back pressure of the alloy filling narrow sections of the mold corresponding to the thin walls of the future casting, due to the limited gas permeability of the casting mold. A liquid self-hardening mixture is quite suitable for the role of a mold material due to its high gas permeability, flexibility, low moisture content and fluidity. Based on the results of the analysis of open sources of information, the mixture flow curve was constructed and analyzed in detail. The curve shows five characteristic stages, each of which is assigned the types of non-Newtonian fluids according to the well-known classification. The presented version of the model representation not only contributes to a deeper understanding of the physical and physicochemical interaction of the components of the mixture, but also provides a theoretical basis for the development of mixtures of new compositions with increased manufacturability, which, in turn, creates the prerequisites for ensuring a consistently high quality of thin-walled steel casting obtained with their use.
Keywords
Hin-walled steel casting, liquid self-hardening mixture, non-Newtonian liquid, flow curve, manufac-turability, gas permeability, fluidity, pliability.