The article presents the process of creating a computer model for predicting the distribution of particles during centrifugal casting using the ANSYS FLUENT 16.0 software module. To predict the distribution of particles by volume in the world at the moment there are several mathematical models. Most of them are based on the steady state assumption: models describing the criteria for dropping particles by a growing crystallization front and models calculating critical particle absorption rates by growing dendritic crystals. Some models attempt to describe the dynamic state of the system or to determine the criterion for capturing non-metallic inclusions by the solidification front during centrifugal casting of metal. The process of creating the new model, its scheme and geometry are described. Its preprocessor takes into account such phenomena as two-phase flow, energy equation, lamellar flow, introduction of discrete phases (strengthening particles), melting/crystallization. The model considers account of interaction of two liquid phases: air and steel melt; interfacial interaction is described by the equation of surface tension. As the materials used, the authors used steel grade 12Kh18N10T as the base metal, carbides of tungsten, boron and yttrium oxide as input particles. During simulation, the physicochemical parameters of these substances were taken into account. The process of modeling the distribution of particles during centrifugal casting using the Skif-Ural computing cluster, included in the TOP-500 of the world’s most powerful computers, is presented. As a result of the simulation, in addition to graphical display, data arrays were obtained that describe the coordinates of each particle at each moment in time in increments of 0.00001 seconds, which allows us to predict the exact location of each particle at each moment of casting. The results of the work indicate that centrifugal casting technology with the introduction of dispersed particles during the casting process allows obtaining dispersion-strengthened metal materials with predicting the distribution of refractory particles.

No abstract

Creating a gradient of properties in a single material is challenging for scientists and engineers. For this purpose, such methods are used as: welding of steels of different chemical compositions, joint rolling of steel sheets, sealing and surfacing of various kinds. All of these methods have a big disadvantage: under load, the material is destroyed in the weakest place - the place where the layers join. In this article, the authors proposed to obtain a gradient of properties in steel castings due to the introduction of dispersed particles of tungsten carbide into the crystallizing melt during centrifugal casting. The particles introduced serve as crystallization centers, accelerate the crystallization process and increase certain types of mechanical properties (hardness, microhardness, tensile strength). In addition, the particles of tungsten carbide have high hardness; therefore, in the structure of the workpieces they serve as reinforcing elements that strengthen the structure. The uneven distribution of particles in the preform being formed is possible for two reasons: tungsten carbide has a density greater than the melt, and besides, centrifugal force acts on them. The article describes the experiment and its results on the production of metal preforms with a gradient of properties. The introduced particles significantly influenced the macro-structure of the prepared castings. The article also presents the results of a study of the effect of particles on the hardness and micro-hardness of the resulting blanks.

No abstract

No abstract