COMPUTER SIMULATION OF CASTING AND SOLIDIFICATION PROCESSES OF STANDARD CAST SAMPLES OF GREY CAST IRON

For standard tension samples of gray cast iron, the possibility of using computer modeling to study factors affecting the morphology of dendritic crystals and the volumetric arrangement of defects of shrinkage origin is shown.

Casting and Solidification of Light Alloys

At present, light alloys based on aluminum, magnesium, titanium, etc [...]

DETERMINATION OF THE NATURE AND SPEED OF CONVECTIVE FLOWS IN THE PHYSICAL SIMULATION OF THE PROCESS OF SOLIDIFICATION OF INGOTS

The paper describes in detail the application of the shadow method for physical modeling of the solidification process of large ingots, for visualizing and quantifying convective flows. As a result of the experiment, the proposed method allowed to visualize convective flows during casting and solidification of the model ingot. At the end of casting, the flows are represented as a vortex movement, as the further solidification of the flow changes to a more uniform appearance, they have a laminar appearance, while their visualization deteriorates. In the initial moments of time, the rate of descending flows is higher than the rate of ascending ones. Further, as the solidification continues, the rate of descending flows decreases, and the rate of ascending flows increases. The results obtained are in good agreement with the literature data, as well as with industrial experiments, which makes it possible to consider this method of studying the convective movement of a liquid in an ingot appropriate.

The stability of the internal cavities of steel casting

The mechanism and causes of the formation of casting defects, manifested in the deviation of the geometry of the internal cavities from the «cylindrical», are investigated. It is shown that the causes of distortion of the geometric shape are associated with deformation of the casting rod during thermal and mechanical interaction with the melt. Using the possibilities of computer simulation in the MAGMASOFT package, the temperature distributions of the metal in the casting body during the casting and solidification were analyzed. Areas of distortion of the geometric shape of the inner part of the casting correspond to the area of the rod subjected to the highest and longest thermal loads. The characteristics of the temperature fields in the respective zones indicate overheating of individual areas of the rod to temperatures causing phase stresses in the structure of the core mixture, sufficient for the occurrence of deformations in it. To eliminate the defect under consideration, two approaches were used to reduce the magnitude of phase stresses in the casting rod and to adjust the design of the rod tooling.

Computer simulation of railway wagon brake disc casting

CAD systems serving as the model for real industrial processes are almost an inseparable part of manufacturing in many industry branches. The use of simulation programs in the foundry industry is perceived as a tool for the visualization of the processes involved in the production of castings. They are also used to resolve possible issues and imperfections before the production begins. Consequently, it enhances the quality and reduces product-manufacturing-related financial costs. The paper tackles the issue of how to resolve the occurrence of defects – shrinkages in the railway wagon disc casting while using a simulation program. The 3D model of the casting and of the system of gates was constructed in the CATIA CAD system. The mere simulation of the casting and solidification process was done in the NovaFlow&Solid program. After evaluating the results of the simulation, the correction of the casting and gates was made in order at once to enhance the quality of the casting and reduce the production costs in the manufacturing of this casting. In the production of the brake disk casting, the main issues are little usage of molten metal during casting and the considerable occurrence of shrinkages, which causes the increased economic costs of its production.

Research and Development of the Solidification of Slab Ingots from Special Tool Steels

The paper describes the research and development of casting and solidification of slab ingots from special tool steels by means of numerical modelling using the finite element method. The pre-processing, processing and post-processing phases of numerical modelling are outlined. Also, problems with determining the thermophysical properties of materials and heat transfer between the individual parts of the casting system are discussed. Based on the type of grade of tool steel, the risk of final porosity is predicted. The results allowed to improve the production technology of slab ingots, and also to verify the ratio, the chamfer and the external/ internal shape of the wall of the new designed slab ingots.

Influence of Cooling Conditions on a Slab’s Chill Zone Formation During Continuous Casting of Steel

The cooling conditions of a slab during continuous casting of steel have an impact on the crystalline structure formation. Numerical methods allow real processes to be modelled. Professional computer programs are available on the market, so the results of their simulations allow us to understand the processes that occur during the casting and solidification of the slab. The study attempts to evaluate the impact of the intensity of the secondary cooling on the chilled zone size. The calculations show the differences in the structure of a slab cast with various speeds while maintaining industrial cooling parameters during operation of a continuous casting machine.

The Dependence of Effective Thermal Conductivity (ETC) of Soil Particulate Beds, on Pressure and Temperature

Effective Thermal Conductivity (ETC) of particulate beds is an important property to many processes in industries such as pharmaceutical, food, nuclear and casting and solidification technologies. This paper presents an experimental research that examines the dependence of the ETC of soil due to changes in the average temperature of the particulate beds, and the stresses on the particles (as derived from the pressure on the top face of the beds).A uni-axial cylindrical experimental system was composed. The ETC was measured by the experimental system while either the pressure on the particulate beds or the average temperature of the beds was changed.