R. Przyłucki

3D modeling of induction hardening of gear wheels

Induction hardening of gear wheels is modeled. The model consists of two nonlinear partial differential equations describing the distributions of magnetic and temperature fields in the system. All material parameters are supposed to be functions of temperature. The model is then solved numerically in the 3D hard-coupled formulation using the professional code FLUX3D supplemented with a number of own scripts and procedures. The methodology is illustrated with a typical example whose results are discussed.

Homogenization of Electromagnetic Force Field During Casting of Functionally Graded Composites

The paper presents the analysis of the process of casting functionally graded composites under alternating electromagnetic field. The process utilizes the effect of electromagnetic buoyancy on nonconductive particles of the reinforcement in the conducting liquid (melted metal). The authors analyzed the possibilities of homogenizing the distribution of electromagnetic field in such a way as to obtain the desired direction of electromagnetic buoyancy and at the same time minimize the stirring of the molten metal, which makes it difficult to receive the optimal distribution of reinforcement in the casting. The suggested solution was to use the conductive elements of the mold to move the nonuniformity of the electromagnetic field outside the casting and a parabolic inductor to smooth the field distribution in the casting.

IMPURITIES REMOVAL PROCESS FROM THE VACUUM INDUCTION FURNACE CHARGE: A NUMERICAL STUDY

The technology of mental melting in a vacuum induction furnace enables the efficient removal of impurities and provides an opportunity to melt refractory metals, such as titanium. These materials can be applied in cutting edge technologies, such as aviation (turbine blades) and biotechnology (prosthesis and implants). To control metallurgical heat and mass processes within an induction furnace, measurements and a numerical analysis can be conducted. In this paper, numerical approaches are discussed. Simulation requires the development of vacuum induction furnace coupling between fluid dynamics and electromagnetic fields. The proposed numerical domain was modelled as a threedimensional slice with a properly defined periodic boundary condition. To define the analysed electromagnetic problem, a set of Maxwell differential equations was specified. A fluid dynamics sub-model was composed of the mass and momentum conservation equations using the volume of fluid multiphase formulation, two-equation k- turbulence model and species transport to track the inclusion position within the melt. The main purpose of this study was an examination of the impurities removal process via the free surface of the melt within an induction furnace. The coupled computations were performed for five operating conditions, including different power inputs of the inductor. The results indicated a strong influence of the inductor power on the free surface area and therefore on the purification process intensity.

Modeling Acoustic Effects During Casting Nanocomposites Under Electromagnetic Field

Casting is one of the most cost-effective methods of producing metal matrix nanocomposites. However, it is extremely difficult to disperse nanoparticles uniformly in a metal matrix due to their large surface-to-volume ratio and their low wettability in liquid metal, which cause their agglomeration and clustering. This paper presents a model of the process of nanocomposite casting where an alternating electromagnetic field is used to induce a standing acoustic wave in the molten metal. The model requires a coupling of electromagnetic field, metal flow field, and acoustic field. It allows optimization of the parameters of the coil supply so as to produce a cavitation phenomenon in the metal, which breaks up the agglomerations of nanoparticles.

Modelling Methods of Magnetohydrodynamic Phenomena Occurring in a Channel of the Device Used to Wash out Spent Automotive Catalyst on Metallic Substrate by a Liquid Metal

The recovery of precious metals is necessary for environmental and economic reasons. Spent catalysts from automotive industry containing precious metals are very attractive recyclable material because as the devices. they have to be periodically renovated and eventually replaced. Among automotive catalysts withdrawn from use, these with metallic carrier constitute quite a big group. Metallic carriers are usually obtained from steel FeCrAl , which is covered by a layer of PGM acting as a catalyst. World literature describes a number of pyro-or hydrometallurgical methods used for recovery of platinum from used automobile catalytic converters. However, all methods, available in the literature, are used to recover platinum from ceramic carrier. This paper presents the new method of removing platinum from the spent catalytic converters applying lead as a collector metal in a device used to wash out platinum by using mangetohydrodynamic pump. The article includes the description of the methods used in modelling magnetohydrodynamic phenomena (coupled analysis of the electromagnetic, temperature and flow fields) occurring in this particular device for this kind of waste. The general phenomena and ways of coupling the various physical fields for this type of calculation have also been described. The basic computational techniques with a discussion of their advantages and disadvantages have been presented.

The Stress Effects Occurring During Induction Heating of Titanium

In this paper multivariant calculations of induction heating of titanium charge are presented. Calculation model consists of: hard coupled electromagnetic and thermal field analysis and weak coupled stress field analysis. A characteristic feature of titanium is low thermal conductivity. This causes problems with the heating of titanium charges, prolonging the heat treatment time. For this reason, it is preferred to use induction heating techniques, which allow to dissipate the power direct inside the heated charge volume. The side effect of intensified heating can be the appearance of harmful thermal stresses due to the large temperature gradients. Two series of simulations, in order to analyze the influence of the frequency and the supply power on the thermal stress and of the sample, was conducted.